Title:
Retainer ring for polishing head
Kind Code:
A1


Abstract:
In order to achieve the above object, the invention provides a retainer ring for polishing head includes: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad. Flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base unit.



Inventors:
Kuwabara, Takayoshi (Tokyo, JP)
Yamada, Soshi (Tokyo, JP)
Application Number:
11/985104
Publication Date:
07/17/2008
Filing Date:
11/14/2007
Assignee:
TOKYO SEIMITSU CO., LTD
Primary Class:
Other Classes:
257/E21.304
International Classes:
B24B37/04; B24B37/30; H01L21/304
View Patent Images:
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Primary Examiner:
MORGAN, EILEEN P
Attorney, Agent or Firm:
PAUL A. FATTIBENE (SOUTHPORT, CT, US)
Claims:
What is claimed is:

1. A retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad and polished while supplying slurry, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, comprising: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad, wherein flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base unit.

2. The retainer ring for polishing head according to claim 1, wherein a plurality of recessed portions are formed in the lower surface of the base unit, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base unit.

3. The retainer ring for polishing head according to claim 1, wherein a plurality of tubular recessed portions are formed in the lower surface of the base unit, columnar projecting portions corresponding to the plurality of recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base unit.

4. The retainer ring for polishing head according to claim 1, wherein a plurality of dovetail-like trenches are formed at desired positions on the lower surface of the base unit, and the plurality of resin blocks are molded on the lower surface of the base unit in which the plurality of trenches are formed by resin casting using a mold to fix the plurality of resin blocks to the lower surface of the base unit.

5. The retainer ring for polishing head according to claim 1, wherein intake holes communicating with the lower surface of the base unit are formed at desired positions in the base unit, respectively, and the plurality of resin blocks temporarily fixed to the lower surface of the base unit by arbitrary temporarily fixing means are fixed to the lower surface of the base unit by suction through the intake holes to fix the plurality of resin blocks to the lower surface of the base unit.

6. A retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad and polished while supplying slurry, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, comprising: a base-unit-equivalent portion made of a highly rigid material, formed to have a ring-like shape, and integrally formed with a retainer ring holder arranged on the polishing head; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base-unit-equivalent portion at almost the same intervals and which serves as a contact side to the polishing pad, wherein flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base-unit-equivalent portion.

7. The retainer ring for polishing head according to claim 6, wherein a plurality of recessed portions are formed in the lower surface of the base-unit-equivalent portion, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base-unit-equivalent portion.

8. The retainer ring for polishing head according to claim 6, wherein a plurality of tubular recessed portions are formed in the lower surface of the base-unit-equivalent portion, columnar projecting portions corresponding to the plurality of recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base-unit-equivalent portion.

9. The retainer ring for polishing head according to claim 6, 7, or 8, wherein an elastic sheet stretched on an upper surface side of the wafer inside the retainer ring has a peripheral portion held between the base-unit-equivalent portion and the resin unit.

10. A retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad to polish the wafer, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, comprising: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad, wherein the resin unit is designed to be replaceable by canceling a fixing state of the resin unit to the lower surface of the base unit.

11. The retainer ring for polishing head according to claim 10, wherein a push-out hole which pushes the resin unit out to remove the resin unit from the lower surface of the base unit is formed in the base unit in advance, and when a fixing state of the resin unit to the lower surface of the base unit is to be canceled, the resin unit is designed to be removed by a rod-like member from the lower surface of the base unit through the push-out hole.

12. The retainer ring for polishing head according to claim 10, wherein force in a direction opposing the direction of the force acting on the resin blocks in a normal operation in which the polishing head rotates is applied to the resin blocks to slide the resin blocks to make it possible to remove the resin unit from the lower surface of the base unit, and when the fixing state of the resin unit to the lower surface of the base unit is to be canceled, the force in the opposite direction is applied to the resin blocks to remove the resin blocks from the lower surface of the base unit.

13. The retainer ring for polishing head according to claim 10, wherein a lock member which locks fixing states of the resin blocks to the lower surface of the base unit extends from the base unit to the resin unit side, and when a fixing state of the resin unit to the lower surface of the base unit is to be canceled, the lock states of the resin blocks set by the lock member are canceled to remove the resin blocks from the lower surface of the base unit.

14. The retainer ring for polishing head according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13, wherein the highly rigid material is a metal, a ceramic, or a highly rigid engineering plastic, and the resin material is an engineering plastic containing polyphenylenesulfide (PPS) and polyetheretherketone (PEEK).

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a retainer ring for polishing head and, in particular, a retainer ring for polishing head which can uniformly polish an entire wafer in chemical mechanical polishing (CMP) and be recycled.

2. Description of Related Art

The following process is known. That is, lithography and etching is performed to an oxide film formed on a semiconductor wafer to form a trench pattern corresponding to a wiring pattern, a conductive film made of Cu or the like to fill the trench pattern is formed on the trench pattern, and an unnecessary portion of the conductive film is polished and removed by CMP to form a wiring pattern or the like. In the process of forming a wiring pattern or the like on a wafer, it is important to uniformly polish the entire wafer up to a portion near an edge.

As a related conventional technique, for example, the following wafer polishing apparatus is known. In the conventional technique, a wafer polishing apparatus which presses and polishes the wafer on a rotating polishing pad while surrounding the wafer with a retainer ring attached to the main body of the polishing head includes: a retainer ring attaching unit having a lower portion to which the retainer ring is detachably attached; a snap ring fixed to the circumference of a contact portion between the retainer ring attaching unit and the retainer ring to attach and fix the retainer ring to the retainer ring attaching unit; and a snap ring cover which surround the circumference of the snap ring and which is slidably arranged upward from a position where the snap ring cover surrounds the circumference of the snap ring.

Since the retainer ring is pressed against the polishing pad together with the wafer, the retainer ring should be worn. At this time, the snap ring cover is slid upward to expand the snap ring and to remove the snap ring from contact portion, whereby the retainer ring is removed from the retainer ring attaching unit. In this manner, the retainer ring is attached or detached to/from the retainer ring attaching unit by a single operation, so that the retainer ring worn by use can be periodically replaced (for example, see Japanese Patent No. 3627143 (pp. 2 to 5, FIGS. 2 and 4))

A conventional retainer ring is generally made of only a resin. For this reason, the retainer ring is poor in rigidity to influence a polishing shaped of the wafer. The entire wafer, especially, a portion near the edge of the wafer may not be uniformly polished depending on polishing conditions. Furthermore, the retainer ring made of the resin is worn by use.

At this time, in the conventional technique described in Patent Document 1, the worn retainer ring is removed from the retainer ring attaching unit and periodically replaced. However, the worn retainer ring cannot be recycled, and the removed retainer ring cannot be held but being discarded. For this reason, an amount of resin of the retainer ring to be discarded is wasted.

SUMMARY OF THE INVENTION

Therefore, a technical problem to be solved to uniformly polish an entire wafer, to make it possible to recycle, and to minimize an amount of resin to be discarded is posed. It is an object of the present invention to solve the problem.

The present invention has been proposed to achieve the above object, and according to a first aspect of the present invention, there is provided a retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad and polished while supplying slurry, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, including: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad, wherein flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base unit.

With this configuration, the base unit is made of the high-rigid material to increase the total rigidity, and a capability of properly holding the circumference of the wafer. In addition to this, a large number of flow paths for slurry are formed at appropriate intervals in the resin unit to easily circulate the supplied slurry around the entire wafer is rose. As a result, the entire wafer can be uniformly polished. In addition, since a contact side to the polishing pad is constituted by the resin unit, fine metal particles which cause a problem in process for the wafer are prevented from being generated. Furthermore, the wafer is suppressed from being damaged by contact.

According to a second aspect of the invention, there is provided the retainer ring for polishing head, wherein a plurality of recessed portions are formed in the lower surface of the base unit, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base unit.

With this configuration, the resin blocks are fitted in and fixed to the recessed portions, respectively, to set fixing positions of the resin blocks at predetermined positions, the flow paths for slurry are formed on the circumference of the ring-like base unit with a predetermined interval. In an operation in which the polishing head rotates, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions to the recessed portions to keep fixing strengths of the resin blocks to the base unit high.

According to a third aspect of the invention, there is provided the retainer ring for polishing head, wherein a plurality of tubular recessed portions are formed in the lower surface of the base unit, columnar projecting portions corresponding to the plurality of recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base unit.

With this configuration, the columnar projecting portions on the resin blocks are pressed into and fitted in tubular recessed portions of the base unit to set the fixing positions of the resin blocks at predetermined positions. In an operation in which the polishing head rotates, circumferential force acting on the resin blocks and generated between the resin blocks and the polishing pad are received by fitting portions between the columnar projecting portions and the tubular recessed portions to keep fixing strengths of the resin blocks to the base unit high.

According to a fourth aspect of the invention, there is provided the retainer ring for polishing head, wherein a plurality of dovetail-like trenches are formed at desired positions on the lower surface of the base unit, and the plurality of resin blocks are molded on the lower surface of the base unit in which the plurality of trenches are formed by resin casting using a mold to fix the plurality of resin blocks to the lower surface of the base unit.

With this configuration, formation of the plurality of resin blocks on the lower surface of the base unit is performed by casting of a resin using a mold, so that the manufacturing cost is reduced. In an operation in which the polishing head rotates, circumferential force acting on the resin blocks and generated between the resin blocks and the polishing pad are mainly received by a resin casting portion to a dovetail-like trench portion formed on the lower surface of the base unit to keep fixing strengths of the resin blocks to the base unit high.

According to a fifth aspect of the invention, there is provided the retainer ring for polishing head, wherein intake holes communicating with the lower surface of the base unit are formed at desired positions in the base unit, and the plurality of resin blocks temporarily fixed to the lower surface of the base unit by arbitrary temporarily fixing means are fixed to the lower surface of the base unit by suction through the intake holes to fix the plurality of resin blocks to the lower surface of the base unit.

With this configuration, when the resin blocks are temporarily fixed to the lower surface of the base unit by using the temporarily fixing means such as screws or the like, the resin blocks are sucked by using vacuum or the like used when the wafer is held on the polishing head by adsorption, so that the resin blocks are fixed to the lower surface of the base unit. At this time, contact surfaces of the resin blocks to the polishing pad are flattened on almost the same plane and fixed by adsorption in a predetermined attaching mode.

According to a sixth aspect of the invention, there is provided a retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad and polished while supplying slurry, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, including: a base-unit-equivalent portion made of a highly rigid material, formed to have a ring-like shape, and integrally formed with a retainer ring holder arranged on the polishing head; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base-unit-equivalent portion at almost the same intervals and which serves as a contact side to the polishing pad, wherein flow paths for the slurry are constituted by spaces between adjacent resin blocks and the lower surface of the base-unit-equivalent portion.

With this configuration, a base-unit-equivalent portion is integrally formed with the retainer ring holder and is made of a highly rigid material, the entire rigidity is improved, and the capability of properly holding the circumference of the wafer is rose. In addition, a large number of flow paths for slurry are formed in the resin unit at arbitrary intervals, so that the supplied slurry is easily circulated around the entire wafer. As a result, the entire wafer can be uniformly polished. Further, since the contact side to the polishing pad is constituted by the resin unit, fine metal particles which cause a problem in process for the wafer are prevented from being generated. Furthermore, the wafer is suppressed from being damaged by contact.

According to a seventh aspect of the invention, there is provided the retainer ring for polishing head, wherein a plurality of recessed portions are formed in the lower surface of the base-unit-equivalent portion, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base-unit-equivalent portion.

With this configuration, the resin blocks are fitted in and fixed to the recessed portions, respectively, so that fixing positions of the resin blocks are set at predetermined positions, respectively. In an operation in which the polishing head rotates, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions to the recessed portions to keep fixing strengths of the resin blocks to the base-unit-equivalent portion high.

According to an eighth aspect of the present invention, there is provided the retainer ring for polishing head, wherein a plurality of tubular recessed portions are formed in the lower surface of the base-unit-equivalent portion, columnar projecting portions corresponding to the plurality of recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base-unit-equivalent portion.

With this configuration, the columnar projecting portions on the resin blocks are pressed into and fitted in tubular recessed portions of the base-unit-equivalent portion to set the fixing positions of the resin blocks at predetermined positions. In an operation in which the polishing head rotates, circumferential force acting on the resin blocks and generated between the resin blocks and the polishing pad are received by fitting portions between the columnar projecting portions and the tubular recessed portions to keep fixing strengths of the resin blocks to the base-unit-equivalent portion high.

According to a ninth aspect of the present invention, there is provided the retainer ring for polishing head, wherein an elastic sheet stretched on an upper surface side of the wafer inside the retainer ring has a peripheral portion held between the base-unit-equivalent portion and the resin unit.

With this configuration, since the base-unit-equivalent portion is integrally formed with the retainer ring holder, an elastic sheet is held at its peripheral portion between the base-unit-equivalent portion and the resin unit and stretched inside the retainer ring.

According to a tenth aspect of the invention, there is provided a retainer ring for polishing head which, when a wafer held by a polishing head is pressed against a rotating polishing pad to polish the wafer, is supported by the polishing head and surrounds a circumference of the wafer while being in contact with the polishing pad, including: a base unit made of a highly rigid material, formed to have a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to the lower surface of the base unit at almost the same intervals and which serves as a contact side to the polishing pad, wherein the resin unit is designed to be replaceable by canceling a fixed state of the resin unit to the lower surface of the base unit.

With this configuration, when the resin unit is worn by use, only the resin unit is replaced to make it possible to recycle the base unit, and an amount of resin to be wasted is minimized to an amount of resin corresponding to the lower half of the retainer ring.

According to an eleventh aspect of the invention, there is provided the retainer ring for polishing head, wherein a push-out hole which pushes the resin unit out to remove the resin unit from the lower surface of the base unit is formed in the base unit in advance, and when a fixing state of the resin unit to the lower surface of the base unit is to be canceled, the resin unit is designed to be removed by a rod-like member from the lower surface of the base unit through the push-out hole.

With this configuration, when the resin unit is worn by use, the rod-like member is inserted into the push-out hole to push each of the resin blocks out, so that the resin unit can be easily and efficiently removed from the lower surface of the base unit. The removing method is particularly effective when the resin blocks are fixed on the lower surface of the base unit by means of press fitting, adhesion, or the like.

According to a twelfth aspect of the present invention, there is provided the retainer ring for polishing head, wherein force in a direction opposing the direction of the force acting on the resin blocks in a normal operation in which the polishing head rotates is applied to the resin blocks to slide the resin blocks to make it possible to remove the resin unit from the lower surface of the base unit, and when the fixing state of the resin unit to the lower surface of the base unit is to be canceled, the force in the opposite direction is applied to the resin blocks to remove the resin blocks from the lower surface of the base unit.

With this configuration, in a general operation, force acting from the internal side of the ring-like retainer ring to the external side thereof acts on the resin blocks in a normal operation. The resin blocks are designed not to be removed from the lower surface of the base unit by the force acting from the internal side to the external side. In contrast to this, the resin blocks are designed to be able to be removed from the lower surface of the base unit by sliding the resin blocks when the force acting from the external side to the internal side is applied. When the resin unit is worn by use, the resin blocks are efficiently removed from the lower surface of the base unit by applying the force acting from the external side to the internal side. The removing method is particularly effective when the resin unit is fixed to the lower surface of the base unit by resin casting.

According to a thirteenth aspect of the invention, there is provided the retainer ring for polishing head, wherein a lock member which locks fixing states of the resin blocks to the lower surface of the base unit extends from the base unit to the resin unit side, and when a fixing state of the resin unit to the lower surface of the base unit is to be canceled, the lock states of the resin blocks set by the lock member are canceled to remove the resin blocks from the lower surface of the base unit.

With this configuration, fixing states of the resin blocks to the lower surface of the base unit in a normal state are locked by the lock member. When the resin unit is worn by use, the lock states of the resin blocks are canceled by the lock member, so that the resin block can be easily and efficiently removed from the lower surface of the base unit.

According to a fourteenth aspect of the invention, there is provided the retainer ring for polishing head, wherein the highly rigid material is a metal, a ceramic, or a highly rigid engineering plastic, and the resin material is an engineering plastic containing polyphenylenesulfide (PPS) and Polyetheretherketone (PEEK).

With this configuration, the base unit and the base-unit-equivalent portion are made of a highly rigid material made of a metal, a ceramic, or a highly rigid engineering plastic, and the entire rigidity is sufficiently high. Since the resin blocks being in contact with the polishing pad are made of the engineering plastic, abrasion is suppressed to a low level, and reliability is improved.

In the invention according to the first aspect, the retainer ring includes: a base unit made of a highly rigid material, formed in a ring-like shape, and supported on a polishing head side; and a resin unit in which a plurality of resin blocks are fixed to a lower surface of the base unit at almost the same intervals and which serves a contact side to the polishing pad, and flow paths for slurry are formed by spaces between adjacent resin blocks and the lower surface of the base unit. For this reason, the capability of properly holding a circumference of the wafer is improved, and the supplied slurry is easily circulated around the entire wafer to make it possible to uniformly polish the entire wafer. Metal particles which cause a problem in process for the wafer can be prevented from being generated. Furthermore, the wafer can be advantageously suppressed from being damaged by contact.

In the invention according to the second aspect, a plurality of recessed portions are formed in the lower surface of the base unit, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base unit. For this reason, the fixing positions of the resin blocks can be set at predetermined positions, respectively. In an operation, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions to the recessed portions to make it possible to advantageously keep fixing strengths of the resin blocks to the base unit high.

In the invention according to the third aspect, a plurality of tubular recessed portions are formed in the lower surface of the base unit, columnar projecting portions corresponding to the tubular recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base unit. For this reason, the fixing positions of the resin blocks can be set at predetermined positions, respectively. In an operation, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions between the columnar projecting portions and the tubular recessed portions to make it possible to advantageously keep fixing strengths of the resin blocks to the base unit high.

In the invention according to the fourth aspect, a plurality of dovetail-like trenches are formed at desired positions on the lower surface of the base unit, and the plurality of resin blocks are molded on the lower surface of the base unit in which the plurality of trenches are formed by resin casting using a mold. For this reason, the formation and fixing of the plurality of resin blocks are performed by resin casting to make it possible to reduce the manufacturing cost.

In an operation, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is mainly received by the resin molding portions to the dovetail-like trenches to make it possible to advantageously keep fixing strengths of the resin blocks to the base unit high.

In the invention according to the fifth aspect, intake holes communicating with the lower surface of the base unit are formed at desired positions in the base unit, respectively, and the plurality of resin blocks temporarily fixed to the lower surface of the base unit by an arbitrary temporarily fixing means are fixed to the lower surface of the base unit by suction through the intake holes to fix the plurality of resin blocks to the lower surface of the basic unit. For this reason, the resin blocks can be fixed to the lower surface of the base unit by adsorption in a predetermined attaching mode by using vacuum or the like used when the wafer is held on the polishing head by adsorption. Therefore, easy fixing of the resin blocks to the base unit can be advantageously achieved.

The invention according to the sixth aspect, the retainer ring includes: a base-unit-equivalent portion integrally formed with a retainer ring holder arranged on a polishing head, made of a highly rigid material, and formed in a ring-like shape; and a resin unit in which a plurality of resin blocks are fixed to a lower surface of the base-unit-equivalent portion at almost the same intervals and which serves a contact side to the polishing pad, wherein flow paths for slurry are formed by spaces between adjacent resin blocks and the lower surface of a base-unit-equivalent portion. For this reason, since the base-unit-equivalent portion is integrally formed with the retainer ring holder and is made of the highly rigid material, easy constitutivity of the base-unit-equivalent portion can be achieved, and an incorporating operation of the retainer ring to the retainer ring holder can be omitted. Furthermore, the capability of properly holding a circumference of the wafer is improved, and the supplied slurry is easily circulated around the entire wafer to make it possible to uniformly polish the entire wafer. In addition, metal particles which cause a problem in process for the wafer can be prevented from being generated, and the wafer can be advantageously suppressed from being damaged by contact.

In the invention according to the seventh aspect, a plurality of recessed portions are formed in the lower surface of the base-unit-equivalent portion, and the resin blocks are fitted in and bonded to, welded to, or screwed in the plurality of recessed portions, respectively, to fix the resin blocks to the lower surface of the base-unit-equivalent portion. For this reason, the fixing positions of the resin blocks can be set at predetermined positions, respectively. In an operation, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions to the recessed portions to make it possible to advantageously keep fixing strengths of the resin blocks to the base-unit-equivalent portion high.

In the invention according to the eighth aspect, a plurality of tubular recessed portions are formed in the lower surface of the base-unit-equivalent portion, columnar projecting portions corresponding to the tubular recessed portions are formed on the resin blocks, respectively, and the columnar projecting portions are pressed into and fitted in the tubular recessed portions, respectively, to fix the plurality of resin blocks to the lower surface of the base-unit-equivalent portion. For this reason, the fixing positions of the resin blocks can be set at predetermined positions, respectively. In an operation, circumferential force acting on the resin blocks and generated by friction between the resin blocks and the polishing pad is received by the fitting portions between the columnar projecting portions and the tubular recessed portions to make it possible to advantageously keep fixing strengths of the resin blocks to the base-unit-equivalent portion high.

In the invention according to the ninth aspect, the elastic sheet stretched inside the retainer ring on the upper surface side of the wafer is held at its peripheral portion between the base-unit-equivalent portion and the resin unit.

For this reason, even though the base-unit-equivalent portion is formed integrally with the retainer ring holder, the elastic sheet required for the function of the polishing head can be advantageously stretched inside the retainer ring.

In the invention according to the tenth aspect, the retainer ring includes: a base unit made of a highly rigid material, formed in a ring-like shape, and supported on a polishing head side; and a resin unit in which a plurality of resin blocks are fixed to a lower surface of the base unit at almost the same intervals and which serves a contact side to the polishing pad, and the resin unit is designed to be replaceable by canceling a fixing state of the resin unit to the lower surface of the base unit. For this reason, the base unit can be recycled, and an amount of resin to be wasted can be advantageously minimized.

In the invention according to the eleventh aspect, a push-out hole which pushes the resin unit out to remove the resin unit from the lower surface of the base unit is formed in the base unit in advance. When a fixing state of the resin unit to the lower surface of the base unit is to be canceled, the resin unit is designed to be removed by a rod-like member from the lower surface of the base unit through the push-out hole.

For this reason, when only the resin unit is to be replaced, the rod-like member is inserted into the push-out hole to push the resin blocks out, so that the resin unit can be easily and efficiently removed from the lower surface of the base unit advantageously.

In the invention according to the twelfth aspect, force in a direction opposing the direction of the force acting on the resin blocks in a normal operation in which the polishing head rotates is applied to the resin blocks to slide the resin blocks to make it possible to remove the resin unit from the lower surface of the base unit. When the fixing state of the resin unit to the lower surface of the base unit is to be canceled, the force in the opposite direction is applied to the resin blocks to remove the resin blocks from the lower surface of the base unit. For this reason, when only the resin block is to be replaced, the resin blocks can be efficiently removed from the lower surface of the base unit advantageously by applying the force acting from the external side to the internal side to the resin blocks.

In the invention according to the thirteenth aspect, a lock member which locks fixing states of the resin blocks to the lower surface of the base unit extends from the base unit to the resin unit side. When the fixing state of the resin unit to the lower surface of the base unit is to be canceled, the lock states of the resin blocks set by the lock member are canceled to remove the resin blocks from the lower surface of the base unit. For this reason, when only the resin unit is to be replaced, the lock states of the resin blocks by the lock member are canceled, so that the resin unit can be easily and efficiently removed from the lower surface of the base unit advantageously.

In the invention according to the fourteenth aspect, the highly rigid material is a metal, a ceramic, or an engineering plastic. Since the resin material is an engineering plastic containing polyphenylenesulfide (PPS) and polyetheretherketone (PEEK), entire rigidity becomes sufficiently high, and the capability of holding the circumference of the wafer can be made sufficiently high. Furthermore, abrasion of the resin unit caused by use can be suppressed to a low level, and the reliability of the retainer ring can be advantageously improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings show retainer rings for polishing head according to embodiments of the present invention, where

FIG. 1 is a perspective view of a chemical mechanical polishing apparatus to which a retainer ring for polishing head is attached;

FIG. 2 is an enlarged longitudinal sectional view of a polishing head in the chemical mechanical polishing apparatus in FIG. 1;

FIGS. 3A to 3C are diagrams showing the retainer ring according to a first embodiment, in which FIG. 3A is a bottom view, FIG. 3b is a partially enlarged side view, and FIG. 3C is an enlarged sectional view along an X-X line in FIG. 3A;

FIGS. 4A and 4B are diagrams showing a first example of a fixing mode in the first embodiment, in which FIG. 4A is a partially enlarged side view similar to that in FIG. 3B and FIG. 4B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 5A and 5B are diagrams showing a second example of a fixing mode in the first embodiment, in which FIG. 5A is a partially enlarged side view similar to that in FIG. 3B and FIG. 5B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 6A and 6B are diagrams showing a third example of a fixing mode in the first embodiment, in which FIG. 6A is a partially enlarged side view similar to that in FIG. 3B and FIG. 6B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 7A and 7B are diagrams showing a fourth example of a fixing mode in the first embodiment, in which FIG. 7A is a partially enlarged side view similar to that in FIG. 3B and FIG. 7B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 8A and 8B are diagrams showing a retainer ring according to a second embodiment, in which FIG. 8A is a partially enlarged side view similar to that in FIG. 3B and FIG. 8B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 9A and 9B are diagrams showing a first example of a fixing mode in the second embodiment, in which FIG. 9A is a partially enlarged side view similar to that in FIG. 3B and FIG. 9B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 10A and 10B are diagrams showing a second example of a fixing mode in the second embodiment, in which FIG. 10A is a partially enlarged side view similar to that in FIG. 3B and FIG. 10B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 11A and 11B are diagrams showing a first example of a removing mode in the third embodiment, in which FIG. 11A is a partially enlarged side view similar to that in FIG. 3B and FIG. 11B is an enlarged sectional view similar to that in FIG. 3C;

FIGS. 12A and 12B are diagrams showing a second example of a removing mode in the third embodiment, in which FIG. 12A is a partially enlarged side view similar to that in FIG. 3B and FIG. 12B is an enlarged sectional view similar to that in FIG. 3C; and

FIGS. 13A and 13B are diagrams showing a third example of a removing mode in the third embodiment, in which FIG. 13A is a partially enlarged side view similar to that in FIG. 3B, FIG. 13B is an enlarged sectional view similar to that in FIG. 3C, and FIG. 13C is a diagram for explaining a removing operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to achieve an object that uniformly polishes an entire wafer, makes it possible to perform recycling, and minimizes an amount of resin to be wasted, when a wafer held by a polishing head is pressed against a rotating polishing pad and polished while being supplied with a slurry, a retainer ring for polishing head which is supported by the polishing head and surrounds the wafer while being in contact with the polishing pad includes: a base unit made of a highly rigid material, formed in a ring-like shape, and supported on the polishing head side; and a resin unit in which a plurality of resin blocks are fixed to a lower surface of the base unit at almost the same intervals and serve as a contact side to the polishing pad. Flow paths for the slurry are formed by spaces between adjacent resin blocks and the lower surface of the base unit, and the resin unit which can be replaced by canceling a fixing state of the resin unit to the lower surface is realized.

A first embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a chemical mechanical polishing apparatus to which a retainer ring for polishing head is attached, and FIG. 2 is an enlarged longitudinal sectional view of the polishing head.

The retainer ring for polishing head according to the embodiment will be described first by using a chemical mechanical polishing apparatus to which the retainer ring for polishing head is attached.

In FIG. 1, a chemical mechanical polishing apparatus 1 is mainly constituted by a platen 2 and a polishing head 3. The platen 2 is formed to have a disk-like shape and connected to a rotating shaft 4 at the center of the lower surface of the platen 2, and rotates by driving of a motor 5 in a direction of an arrow A. A polishing pad 6 is stuck on the upper surface of the platen 2, and a slurry which is a mixture of a polishing agent and a chemical agent is supplied from a nozzle (not shown) onto the polishing pad 6.

The polishing head 3, as shown in FIG. 2, is mainly constituted by a head main body 7, a carrier 8, a retainer ring 9, a retainer ring pressing unit 10, an elastic sheet 11, a carrier pressing unit 16, and control means such as air.

The head main body 7 is formed to have a disk-like shape and connected to a rotating shaft 12 (see FIG. 1) at the center of the upper surface of the head main body 7. The head main body 7 is axially fixed to the rotating shaft 12 and driven by a motor (not shown) to rotate in a direction of an arrow B in FIG. 1.

The carrier 8 is formed to have a disk-like shape and arranged at the center of the head main body 7. A dry plate 13 is arranged between a center portion of the upper surface of the carrier 8 and a lower central portion of the head main body 7, and receives rotation transmitted from the head main body 7 through pins 14.

An operational transformer main body 15a is fixed between a lower central portion of the dry plate 13 and an upper central portion of the carrier 8, a core 15b of an operational transformer 15 is fixed to an upper central portion of the carrier 8, and a polishing state signal of a conductive film (not shown) made of Cu or the like, connected to a control unit (not shown), and formed on a wafer W (lower side in FIG. 2) is output to the control unit.

A carrier pressing member 16a is arranged on a peripheral portion of the upper surface of the carrier 8. The carrier 8 receives pressing force transmitted from a carrier pressing unit 16 through the carrier pressing member 16a.

An air-blowing port 19 to blow air from an air float line 17 onto the elastic sheet 11 is formed in the lower surface of the carrier 8. The air float line 17 is connected to an air charging pump 21 serving as an air supply source through an air filter 20 and an automatic opening/closing valve V1. Air blowing from the air-blowing port 19 is executed by switching the automatic opening/closing valve V1.

A hole 22 to obtain a vacuum state or to blow deionized water (DIW: pure water) or air out if necessary is formed in the lower surface of the carrier 8. The suction of air is executed by driving a vacuum pump 23. An automatic opening/closing valve V2 is formed on a vacuum line 24, and a vacuum operation and supply of the DIW are executed through the vacuum line 24 by switching the automatic opening/closing valve V2.

The air supply from the air float line 17, the vacuum operation from the vacuum line 24, and supply of the DIW are executed by a command signal from the control unit.

The carrier pressing unit 16 is arranged on an edge of the central portion of the lower surface of the head main body 7. The carrier pressing unit 16 gives pressing force to the carrier pressing member 16a to transmit the pressing force to the carrier 8 connected to the carrier pressing member 16a. The carrier pressing unit 16 is preferably constituted by a rubber-sheet airbag 25 which expands or constricts by sucking or exhaust air. An air supply mechanism (not shown) to supply air is connected to the airbag 25.

The retainer ring 9 is formed to have a ring-like shape and arranged on the circumference of the carrier 8. The retainer ring 9 is attached to a retainer ring holder 27 arranged on the polishing head 3, and the elastic sheet 11 is stretched on the inner peripheral portion of the retainer ring 9.

The elastic sheet 11 is formed to have a circular shape, and has a plurality of holes 22 formed therein. The elastic sheet 11 is held between the retainer ring 9 and the retainer ring holder 27 at the peripheral portion to be stretched inside the retainer ring 9.

An air chamber 29 is formed between the carrier 8 and the elastic sheet 11 under the carrier 8 in which the elastic sheet 11 is stretched. The wafer W on which a conductive film is formed is pressed against the carrier 8 through the air chamber 29. The retainer ring holder 27 is attached through a snap ring 31 to an attaching member 30 formed in the shape of a ring. A retainer ring pressing member 10a is connected to the attaching member 30. The retainer ring 9 receives pressing force transmitted from the retainer ring pressing unit 10 through the retainer ring pressing member 10a.

The retainer ring pressing unit 10 is arranged on a circumferential portion of the lower surface of the head main body 7 and gives pressing force to the retainer ring pressing member 10a to press the retainer ring 9 connected to the retainer ring pressing member 10a against the polishing pad 6.

In the chemical mechanical polishing apparatus 1, the polishing head 3 is placed on the wafer W the conductive film of which has not been polished and which is in a standby state by a moving mechanism (not shown). The vacuum line 24 of the polishing head 3 is operated to vacuum the air chamber 29 on the lower surface of the elastic sheet 11 through a vacuum port 19a and the hole 22 (vacuum hole). In this manner, the wafer W is held by adsorption, and the polishing head 3 which holds the wafer W by adsorption is carried onto the platen 2 by the moving mechanism. The wafer W is placed on the platen 2 such that the conductive film is in contact with the polishing pad 6.

The operation of the vacuum line 24 is then canceled, and air is supplied from a pump (not shown) into the airbag 25 to expand the airbag 25. At the same time, air is supplied from the air-blowing port 19 formed in the carrier 8 into the air chamber 29. In this manner, the internal pressure of the air chamber 29 increases.

By the expansion of the airbag 25, the conductive film on the upper portion of the wafer W and the retainer ring 9 are pressed against the polishing pad 6 at a predetermined pressure. In this state, the platen 2 is rotated in the direction of the arrow A in FIG. 1, and the polishing head 3 is rotated in the direction of the arrow B in FIG. 1. Slurry is supplied from a nozzle (not shown) onto the rotating polishing pad 6, and the conductive film on the upper portion of the wafer W is polished while surrounding the circumference of the wafer W with the retainer ring 9.

The details of a configuration, an operation, and an effect of the retainer ring for polishing head according to the embodiment will be described below with reference to FIGS. 3A to 7B. FIGS. 3A to 3C are diagrams showing the retainer ring, in which FIG. 3A is a bottom view, FIG. 3B is a partially enlarged side view, and FIG. 3C is an enlarged sectional view along an X-X line in FIG. 3A.

The retainer ring 9 of the embodiment has a two-layered structure constituted by a ring-like base unit 9A supported on the polishing head 3 side through the retainer ring holder 27 and a resin unit 9B serving as a contact side to the polishing pad 6. The resin unit 9B is constructed such that a plurality of resin blocks 9b are fixed on the lower surface of the base unit 9A at almost the same intervals.

A plurality of slurry flow paths 18 each are constituted by a trench formed by spaces between adjacent resin blocks 9b and the lower surface of the base unit 9A.

The base unit 9A is made of a highly rigid material. As the highly rigid material, a metal such as stainless steel or aluminum, a ceramic, or an engineering plastic having high rigidity is used. As a resin material for constituting the resin block 9b, an engineering plastic containing polyphenylenesulfide (PPS) and polyetheretherketone (PEEK) is used.

The retainer ring 9 has sufficiently high total rigidity since the base unit 9A is made of a highly rigid material, and the capability of properly holding the circumference of the wafer W can be made sufficiently high. In addition to this, the large number of slurry flow paths 18 are formed in the resin unit 9B at arbitrary intervals. For this reason, the slurry supplied onto the polishing pad 6 is easily circulated around the entire wafer W in the operation. As a result, the entire wafer W even including a portion close to the edge can be uniformly polished.

Since each of the resin blocks 9b is made of a resin material of an engineering plastic, fine metal particles or the like which cause a problem in process for the wafer W can be prevented from being generated. Furthermore, wearing of the resin blocks 9b caused by use can be suppressed to a low level, and reliability of the retainer ring 9 can be improved.

A first example to a fourth example of the fixing mode of the resin blocks 9b to the lower surface of the base unit 9A will be sequentially described.

A. The resin blocks are fitted and bonded to, welded to, or screwed in the recessed portions of the base unit, respectively. FIGS. 4A and 4B are diagrams showing the first example of the fixing mode in the embodiment. FIG. 4A is a partially enlarged side view similar to that in FIG. 3B, and FIG. 4B is an enlarged sectional view similar to that in FIG. 3C.

In FIG. 4A, recessed portions 32 are formed at a position where each of the resin blocks 9b is fixed on the lower surface of the base unit 9A. The resin blocks 9b are fitted and bonded to, welded to, or screwed in the recessed portions 32, respectively, and the plurality of resin blocks 9b are fixed to the lower surface of the base unit 9A to constitute the resin unit 9B.

In the first example, the resin blocks 9b are fitted in and fixed to the recessed portions 32, respectively, so that fixing positions of the resin blocks 9b can be set at predetermined positions, respectively. As a result, the slurry flow path 18 can be formed on the whole circumference of the lower surface of the base unit 9A having the ring-like shape at a predetermined interval. In an operation in which the polishing head 3 rotates, circumferential force acting on the resin blocks 9b and generated by friction between the resin blocks 9b and the polishing pad 6 is received by the fitting portions to the recessed portions 32 to keep fixing strengths of the resin blocks 9b to the base unit 9A high.

B. The columnar projecting portions on the resin blocks are pressed into the tubular recessed portions of the base unit, respectively. FIGS. 5A and 5B are diagrams showing a second example of a fixing mode in the embodiment, in which FIG. 5A is a partially enlarged side view similar to that in FIG. 3B, and FIG. 5B is an enlarged sectional view similar to that in FIG. 3C.

In FIGS. 5A and 5B, a plurality of cylindrical or rectangular tubular recessed portions 33a are formed in the lower surface of the base unit 9A. On the other hand, cylindrical columnar or rectangular columnar projecting portions 33b corresponding to the tubular recessed portions 33a are formed in the resin blocks 9b, respectively. The columnar projecting portions 33b are pressed into and fitted in the tubular recessed portions 33a, respectively, to fix the plurality of resin blocks 9b to the lower surface of the base unit 9A, so that the resin blocks 9b are constituted.

In the second example, the columnar projecting portions 33b on the resin block 9b side are pressed into and fitted in the tubular recessed portions 33a in the base unit 9A, respectively, so that the fixing positions of the resin blocks 9b can be set at predetermined positions, respectively. In an operation in which the polishing head 3 rotates, circumferential force acting on the resin blocks 9b and generated by friction between the resin blocks 9b and the polishing pad 6 is received by the fitting portions between the columnar projecting portions 33b and the tubular recessed portions 33a to keep fixing strengths of the resin blocks 9b to the base unit 9A high.

C. The plurality of resin blocks are integrally formed on the lower surface of the base unit. FIGS. 6A and 6B are diagrams showing a third example of a fixing mode in the first embodiment, in which FIG. 6A is a partially enlarged side view similar to that in FIG. 3B and FIG. 6B is an enlarged sectional view similar to that in FIG. 3C.

In FIG. 6A, a plurality of dovetail-like trenches 34 are formed at positioned where the resin blocks 9b are fixed on the lower surface of the base unit 9A, respectively. The plurality of resin blocks 9b are casted on the lower surface of the base unit 9A on which trenches 34 are formed by resin casting using a mold 35 to fix the plurality of resin blocks 9b to the lower surface of the base unit 9A, so that the resin unit 9B is constituted.

In the third example, since the formation and fixing of the plurality of resin blocks 9b to the lower surface of the base unit 9A are performed by resin casting, the manufacturing cost can be reduced. In an operation in which the polishing head 3 rotates, circumferential force acting on the resin blocks 9b and generated by friction between the resin blocks 9b and the polishing pad 6 is mainly received by the resin molding portions to the dovetail-like trenches 34 to make it possible to advantageously keep fixing strengths of the resin blocks 9b to the base unit 9A high.

D. The resin blocks are fixed to the lower surface of the base unit by adsorption. FIGS. 7A and 7B are diagrams showing a fourth example of a fixing mode in the first embodiment, in which FIG. 7A is a partially enlarged side view similar to that in FIG. 3B and FIG. 7B is an enlarged sectional view similar to that in FIG. 3C.

In FIGS. 7A and 7B, intake holes 36 communicating with the lower surface of the base unit 9A are formed at positions where the resin blocks 9b are fixed on the base unit 9A, respectively. The resin blocks 9b are temporarily fixed to the lower surface of the base unit by using a temporarily fixing means such as temporary adhesion or screw cramp. In this state, the resin blocks 9b are sucked through the intake holes to fix the plurality of resin blocks 9b to the lower surface of the base unit 9A, so that the resin unit 9B is constituted.

At this time, contact surfaces of the resin blocks 9b to the polishing pad 6 are flattened on almost the same plane, and the resin blocks 9b are fixed by adsorption in a predetermined attaching mode. As the adsorption means, vacuum or the like used when the wafer W is held on the polishing head 3 by adsorption is used.

In the fourth embodiment, the resin blocks 9b are fixed to the lower surface of the base unit 9A by adsorption in the predetermined attaching mode using the vacuum or the like used when the wafer W is held to the polishing head 3 by adsorption. Therefore, the resin blocks 9b can be easily fixed to the base unit 9A.

Second Embodiment

The details of a configuration, an operation, and an effect of a retainer ring for polishing head according to a second embodiment of the present invention will be described below with reference to FIGS. 8A to 10B. FIGS. 8A and 8B are diagrams showing a retainer ring according to the embodiment, in which FIG. 8A is a partially enlarged side view similar to that in FIG. 3B and FIG. 8B is an enlarged sectional view similar to that in FIG. 3C.

A retainer ring 9 according to the embodiment is constituted by a base-unit-equivalent portion 9C which is integrally formed with the retainer ring holder 27 and formed in the shape of a ring and a resin unit 9B serving as a contact side to the polishing pad 6. The resin unit 9B is constructed such that a plurality of resin blocks 9b are fixed on the lower surface of the base-unit-equivalent portion 9C at almost the same intervals.

A plurality of slurry flow paths 18 each are constituted by a trench formed by spaces between adjacent resin blocks 9b and the lower surface of the base-unit-equivalent portion 9C.

The base-unit-equivalent portion 9C is made of the same highly rigid material as in the first embodiment. As a resin material for constituting the resin block 9b, an engineering plastic containing PPS and PEEK is used.

In this manner, in the retainer ring 9 according to the embodiment, the base-unit-equivalent portion 9C is integrally formed with the retainer ring holder 27, and the peripheral portion of the elastic sheet 11 is held between the lower surface of the base-unit-equivalent portion 9C and the resin unit 9B.

In the retainer ring 9, the base-unit-equivalent portion 9C and the retainer ring holder 27 are made of the highly rigid material and are integrated with each other to make it possible to achieve easy constitutivity of the base-unit-equivalent portion 9C and to omit an incorporating operation of the retainer ring 9 to the retainer ring holder 27.

The capability of appropriately holding the circumference of the wafer W is improved, and the slurry supplied is circulated around the entire wafer W, so that the entire wafer W even including a portion close to the edge can be uniformly polished. Furthermore, fine metal particles or the like which cause a problem in process for the wafer W can be prevented from being generated, and the wafer W can be prevented from being damaged by contact.

Furthermore, even though the base-unit-equivalent portion 9C is integrally formed with the retainer ring holder 27, the elastic sheet 11 required for the function of the polishing head 3 can be stretched inside the retainer ring 9.

First and second examples of the fixing mode of the resin blocks 9b to the lower surface of the base-unit-equivalent portion 9C will be sequentially described below.

A. The resin blocks are fitted in recessed portions of the base-unit-equivalent portion and bonded to, welded to, or screwed in the recessed portions, respectively. FIGS. 9A and 9B are diagrams showing the first example of the fixing mode in the embodiment, in which FIG. 9A is a partially enlarged side view similar to that in FIG. 3B and FIG. 9B is an enlarged sectional view similar to that in FIG. 3C.

In FIG. 9A, recessed portions 37 are formed at positions where the resin blocks 9b are fixed on the lower surface of the base-unit-equivalent portion 9C, respectively. The resin blocks 9b are fitted in and bonded to, welded to, or screwed in the recessed portions 37, respectively, to fix the plurality of resin blocks 9b to the lower surface of the base-unit-equivalent portion 9C, so that the resin unit 9B is constituted. The peripheral portion of the elastic sheet 11 is held between the lower surface of the base-unit-equivalent portion 9C and the resin unit 9B.

In the first example, the resin blocks 9b are fitted in and fixed to the recessed portions 37, respectively, so that fixing positions of the resin blocks 9b can be set at predetermined positions, respectively. As a result, the slurry flow path 18 can be formed on the whole circumference of the lower surface of the base-unit-equivalent portion 9C at a predetermined interval. In an operation in which the polishing head 3 rotates, circumferential force acting on the resin blocks 9b and generated by friction between the resin blocks 9b and the polishing pad 6 is received by the fitting portions to the recessed portions 37 to keep fixing strengths of the resin blocks 9b to the base unit 9C high.

B. The columnar projecting portions on the resin blocks are pressed into the tubular recessed portions of the base unit, respectively. FIGS. 10A and 10B are diagram showing a second example of the fixing mode in the embodiment, in which FIG. 10A is a partially enlarged side view similar to that in FIG. 3B, and FIG. 10B is an enlarged sectional view similar to that in FIG. 3C.

In FIGS. 10A and 10B, a plurality of cylindrical or rectangular tubular recessed portions 33a are formed in the lower surface of the base-unit-equivalent portion 9C. On the other hand, cylindrical columnar or rectangular columnar projecting portions 33b corresponding to the tubular recessed portions 33a are formed in the resin blocks 9b, respectively. The columnar projecting portions 33b are pressed into and fitted in the tubular recessed portions 33a, respectively, to fix the plurality of resin blocks 9b to the lower surface of the base-unit-equivalent portion 9C, so that the resin unit 9B is 9B is constituted. The peripheral portion of the elastic sheet 11 is held between the lower surface of the base-unit-equivalent portion 9C and the resin unit 9B.

In the second example, the columnar projecting portions 33b on the resin block 9b side are pressed into and fitted in the tubular recessed portions 33a in the base-unit-equivalent portion 9C, respectively, so that the fixing positions of the resin blocks 9b can be set at predetermined positions, respectively. In an operation in which the polishing head 3 rotates, circumferential force acting on the resin blocks 9b and generated by friction between the resin blocks 9b and the polishing pad 6 is received by the fitting portions between the columnar projecting portions 33b and the tubular recessed portions 33a to keep fixing strengths of the resin blocks 9b to the base-unit-equivalent portion 9C high.

Third Embodiment

The details of a configuration, an operation, and an effect of a retainer ring for polishing head according to a third embodiment of the present invention will be described below with reference to FIGS. 11A to 13B. In this embodiment, in the retainer ring 9 having the base unit 9A and the resin unit 9B described in the first embodiment, the fixing state of the resin unit 9B to the lower surface of the base unit 9A is canceled to make it possible to replace the resin unit 9B.

When the resin unit 9B is worn by use, only the resin unit 9B is replaced to make it possible to recycle the base unit 9A and to minimize an amount of resin to be wasted to an amount of resin corresponding to the lower half of the retainer ring 9.

First to third examples of the fixing canceling mode of the resin unit 9B to the lower surface of the base unit 9A will be sequentially described below.

A. Push-out holes to push and remove a resin unit are formed on a base unit. FIGS. 11A and 11B are diagrams showing a first example of a removing mode in the embodiment, in which FIG. 11A is a partially enlarged side view similar to that in FIG. 3B, and FIG. 11B is an enlarged sectional view similar to that in FIG. 3C.

In FIG. 11B, a predetermined number of the push-out holes 38 to push the resin unit 9B to remove the resin unit 9B from the lower surface of the base unit 9A are formed in the base unit 9A in advance. When the fixing state of the resin unit 9B to the lower surface of the base unit 9A is to be canceled, rod-like members (not shown) are inserted into the push-out holes 38 to push the resin blocks 9b, respectively, so that the resin unit 9B is removed from the lower surface of the base unit 9A.

This extracting method is particularly effective when the resin blocks 9b are fixed to the lower surface of the base unit 9A by means of press fit or bonding in the first embodiment. When the resin blocks 9b are fixed by means of bonding or the like, the extraction is more effective by appropriately heating the resin blocks 9b before the resin blocks 9b are pushed out.

In the first example, when the resin unit 9B is worn by use, the rod-like members are inserted into the push-out holes 38 to push the resin blocks 9b out, respectively, so that the resin unit 9B can be easily and efficiently removed from the lower surface of the base unit 9A. As a result, the base unit 9A can be recycled, and an amount of resin to be wasted can be minimized to an amount of resin corresponding to the lower half of the retainer ring 9.

B. Force in a direction in which the force does not act in a normal state is applied to the resin blocks to remove the resin unit. FIGS. 12A and 12B are diagrams showing a second example of a removing mode in the embodiment, in which FIG. 12A is a partially enlarged side view similar to that in FIG. 3B and FIG. 12B is an enlarged sectional view similar to that in FIG. 3C.

In FIG. 12B, force acting from the internal side of the ring-like retainer ring 9 to the external side thereof in a normal operation is applied to the resin blocks 9b. The resin blocks 9b are hooked on external hooking portions 39 not to remove the resin blocks 9b from the lower surface of the base unit 9A by the force acting from the internal side to the external side. In contrast to this, the resin blocks 9b are designed such that the resin blocks 9b can be slidably removed when force acting from the external side to the internal side as shown in FIG. 12B.

When the fixing state of the resin unit 9B to the lower surface of the base unit 9A is canceled, the force acting from the external side to the internal side is applied to the resin blocks 9b to remove the resin blocks 9b from the lower surface of the base unit 9A.

This removing method is particularly effective when the resin unit 9B is fixed to the lower surface of the base unit 9A by resin casting in the first embodiment.

In the second example, when the resin unit 9B is worn by use, the force acting from the external side to the internal side is applied to the resin blocks 9b, so that the resin unit 9B can be efficiently removed from the lower surface of the base unit 9A. As a result, as in the configuration described above, the base unit 9A can be recycled, and an amount of resin to be wasted can be minimized to an amount of resin corresponding to the lower half of the retainer ring 9.

C. A locking state set by locking members is canceled to remove the resin unit. FIGS. 13A and 13B are diagrams showing a third example of a removing mode in the embodiment, in which FIG. 13A is a partially enlarged side view similar to that in FIG. 3B, FIG. 13B is an enlarged sectional view similar to that in FIG. 3C, and FIG. 13C is a diagram for explaining a removing operation.

In FIGS. 13A and 13B, the dovetail-like trenches 34 are formed at positions where the resin blocks 9b are fixed on the lower surface of the base unit 9A, respectively. Lock members 40 are arranged at positions on the circumference surface of the base unit 9A corresponding to the positions where the resin blocks 9b are fixed such that the lock members 40 are attachable or detachable by screwing screws 41 in or off.

When each of the upper portions of the resin blocks 9b is fitted in each of the dovetail-like trench 34, the front and the rear of the resin block 9b (left and right in FIG. 13B) are hooked by an internal hook portions 42 and the lock member 40 attached to the position of the circumference surface of the base unit 9A and fixed to the lower surface of the base unit 9A by screwing the screw 41 in.

When the fixing state of the resin unit 9B to the lower surface of the base unit 9A is to be canceled, as shown in FIG. 13C, the screws 41 are screwed off to remove the lock members 40 (cancel of lock), and force acting from the internal side of the retainer ring 9 to the external side thereof is applied to the resin blocks 9b to slide the resin blocks 9b. In this manner, the resin blocks 9b are removed from the lower surface of the base unit 9A.

In the third example, when the resin unit 9B is worn by use, the lock members 40 are removed to cancel the lock states of the resin blocks 9b set by the lock members 40, so that the resin blocks 9b can be easily and efficiently removed from the lower surface of the base unit 9A. As a result, as in the configuration described above, the base unit 9A can be recycled, and an amount of resin to be wasted can be minimized to an amount of resin corresponding to the lower half of the retainer ring 9.

Various modifications of the invention can be effected without departing from the spirit and scope of the invention, and the present invention covers the modifications as a matter of course.