Title:
Substrate processing apparatus and substrate processing method
Kind Code:
A1


Abstract:
A substrate processing apparatus and a substrate processing method can appropriately control the charge of a substrate depending on the type of wet processing, thereby reducing defective processing due to static electricity on the surface of the substrate. The substrate processing apparatus includes: a static electricity adjustment section for adjusting static electricity on a substrate; and a wet processing apparatus for carrying out wet processing of the static electricity-adjusted substrate. The static electricity adjustment section removes static electricity from the substrate or charges the substrate into a desired charged state, for example.



Inventors:
Mishima, Koji (Tokyo, JP)
Suzuki, Hidenao (Tokyo, JP)
Nomura, Kazufumi (Tokyo, JP)
Kaneko, Hisashi (Fujisawa-shi, JP)
Toyoda, Hiroshi (Kamakura-shi, JP)
Application Number:
11/111774
Publication Date:
11/03/2005
Filing Date:
04/22/2005
Primary Class:
Other Classes:
204/198, 204/224M, 205/660
International Classes:
C23C18/16; C23F1/00; C23F1/08; C23C18/18; C23G3/02; C25D5/34; C25D7/12; C25D17/00; C25D21/12; C25F3/12; C25F3/30; C25F7/00; H01L21/00; H01L21/02; H01L21/304; H01L21/306; H01L21/3063; (IPC1-7): C25D5/34; C25D17/00; C25F7/00
View Patent Images:



Primary Examiner:
ANGADI, MAKI A
Attorney, Agent or Firm:
WENDEROTH, LIND & PONACK, L.L.P. (Washington, DC, US)
Claims:
1. A substrate processing apparatus comprising: a static electricity adjustment section for adjusting static electricity on a substrate; and a wet processing apparatus for carrying out wet processing of the static electricity-adjusted substrate.

2. The substrate processing apparatus according to claim 1, wherein the wet processing apparatus is comprised of at least one of an electroplating apparatus, an electroless plating apparatus, a CMP apparatus, an electrolytic etching apparatus, an electrolytic polishing apparatus, a chemical etching apparatus and a cleaning apparatus.

3. The substrate processing apparatus according to claim 1, wherein the static electricity adjustment section is adapted to remove static electricity from the substrate.

4. The substrate processing apparatus according to claim 3, wherein the removal of static electricity is effected by grounding the substrate.

5. The substrate processing apparatus according to claim 1, wherein the static electricity adjustment section is adapted to charge the substrate into a desired charged state.

6. The substrate processing apparatus according to claim 5, wherein the static electricity adjustment section includes a static electricity sensor for detecting the charge of the substrate, a charging unit for charging the substrate, and a control section for controlling the charging unit.

7. The substrate processing apparatus according to claim 1, wherein the static electricity adjustment section is provided in a substrate transport robot for transporting the substrate to the wet processing apparatus.

8. The substrate processing apparatus according to claim 1, wherein the static electricity adjustment section is provided in a substrate transport route for transport of the substrate to the wet processing apparatus.

9. The substrate processing apparatus according to claim 1, wherein the static electricity adjustment section is provided in the wet processing apparatus.

10. A substrate processing method comprising: adjusting static electricity on a substrate; and carrying out wet processing of the static electricity-adjusted substrate.

11. The substrate processing method according to claim 10, wherein the wet processing comprises at least one of electroplating, electroless plating, CMP, electrolytic etching, electrolytic polishing, chemical etching and cleaning.

12. The substrate processing method according to claim 10, wherein adjusting static electricity on a substrate is performed by removing static electricity from the substrate.

13. The substrate processing method according to claim 12, wherein the removal of static electricity from the substrate is effected by grounding the substrate.

14. The substrate processing method according to claim 10, wherein adjusting static electricity on a substrate is performed by charging the substrate into a desired charged state.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate processing apparatus and a substrate processing method, and more particularly to a substrate processing apparatus and a substrate processing method which are useful for carrying out wet processing of a surface of the substrate by bringing the surface of the substrate into contact with a processing liquid, such as a liquid chemical or pure water.

2. Description of the Related Art

In place of dry processes which have been principally employed for the formation of LSI interconnects or the like on a semiconductor substrate, wet processes, such as plating, chemical-mechanical polishing (CMP), electrolytic etching, electrolytic polishing and cleaning, are increasing being employed these days. For example, a so-called damascene process, which comprises embedding a metal (conductive material), such as aluminum, and more recently silver or copper, by plating into interconnect trenches and contact holes formed in the surface of a substrate, followed by removal of an extra metal by CMP, is becoming to be used.

FIGS. 1A through 1C illustrate, in a sequence of process steps, an example of forming copper interconnects on a substrate. First, as shown in FIG. 1A, an insulating film 2 of SiO2 or a low-k material is deposited on a conductive layer 1a on a semiconductor base 1 having formed semiconductor devices. Contact holes 3 and interconnect trenches 4 are formed in the insulating film 2 by performing a lithography/etching technique. Thereafter, a barrier layer 5 of TaN or the like is formed on an entire surface, and a seed layer 7, serving as an electric supply layer in electroplating, is formed on the barrier layer 5 by sputtering, CVD, or the like.

Next, as shown in FIG. 1B, copper plating of the surface of the substrate W is carried out to fill the contact holes 3 and the interconnect trenches 4 with copper and, at the same time, deposit a copper film 6 on the insulating film 2. Thereafter, the copper film 6, the seed layer 7 and the barrier layer 5 on the insulating film 2 are removed by chemical-mechanical polishing (CMP) so as to make the surface of the copper film 6, filled in the contact holes 3 and the interconnect trenches 4, substantially flush with the surface of the insulating film 2. Interconnects composed of the copper film 6 are thus formed in the insulating film 2, as shown in FIG. 1C.

It is common practice in dry processes to control the static electricity of a substrate. In contrast, no great importance has hitherto been attached to the control of the static electricity of a substrate in wet processes.

FIG. 2 shows a layout plan of a conventional common substrate processing apparatus for carrying out electroplating. The substrate processing apparatus includes an apparatus frame 12. A substrate in a dry state is carried into the apparatus frame 12 from a substrate cassette 10; the substrate is processed inside the apparatus frame 12; and the substrate after processing, in a dry state, is taken out of the apparatus frame 12. Inside the apparatus frame 12 are disposed a stage 14, two post-cleaning apparatuses 16, and four electroplating apparatuses 20 connected via piping to a plating solution supply/recovery apparatus 18. Further, a movable first substrate transport robot 22 for transferring a substrate between the substrate cassette 10 and the stage 14, and a movable second substrate transport robot 24 for transferring the substrate among the stage 14, one of the post-cleaning apparatuses 16 and one of the electroplating apparatuses 20 are provided inside the apparatus frame 12.

A substrate in a dry state, which has been taken out of the substrate cassette 10 and placed on the stage 14 by the first substrate transport robot 22, is transported by the second substrate transport robot 24 to the electroplating apparatus 20 where electroplating of the substrate is carried out. The substrate after plating is transported to the post-cleaning apparatus 16 where the substrate is post-cleaned and dried. Thereafter, the substrate is placed on the stage 14, and is then returned by the first substrate transport robot 22 to the original position in the substrate cassette 10.

When a substrate in a dry state, which has been carried into an apparatus frame, is in a charged state, particles, organic or inorganic compounds, etc., having the opposite polarity, are likely to be adsorbed to the surface of the substrate. Further, in case a liquid chemical (processing liquid), such as a plating solution, for wet processing has a polarity, the contact efficiency between the processing liquid and the substrate can decrease, which can result in defective processing in a local or global region of the substrate.

This defective processing becomes more marked as the processing size of substrate decreases. For example, a decrease in yield due to defective processing becomes a considerable problem when forming 90 nm-node or later-generation interconnects by the above-described damascene process, though it is negligible with 130 nm-node interconnects. Further, the type of interconnect material affects defective processing. In particular, though there is almost no appreciable defective processing with aluminum interconnects, defective processing is marked with copper interconnects. In addition, use of a low-k material, such as an organic material or a porous material, for an insulating film increases defective processing.

The defective processing herein refers to deficient metal deposition, uneven metal deposition, etc. in plating, insufficient polishing, over-polishing, pit formation, corrosion, etc. in CMP or electrolytic processing, and poor cleaning, corrosion, etc. in cleaning.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above situation in the related art. It is therefore an object of the present invention to provide a substrate processing apparatus and a substrate processing method which can appropriately control the charge of a substrate depending on the type of wet processing, thereby reducing defective processing due to static electricity on a surface of the substrate.

In order to achieve the above object, the present invention provides a substrate processing apparatus comprising: a static electricity adjustment section for adjusting static electricity on a substrate; and a wet processing apparatus for carrying out wet processing of the static electricity-adjusted substrate.

The wet processing apparatus may be comprised of at least one of an electroplating apparatus, an electroless plating apparatus, a CMP apparatus, an electrolytic etching apparatus, an electrolytic polishing apparatus, a chemical etching apparatus and a cleaning apparatus.

The static electricity adjustment section may be adapted to remove static electricity from the substrate. The removal of static electricity can be effected, for example, by grounding the substrate.

Alternatively, the static electricity adjustment section may be adapted to charge the substrate into a desired charged state. In this case, the static electricity adjustment section may include a static electricity sensor for detecting the charge of the substrate, a charging unit for charging the substrate, and a control section for controlling the charging unit.

The static electricity adjustment section may be provided in at least one of a substrate transport robot for transporting the substrate to the wet processing apparatus, a substrate transport route for transport of the substrate to the wet processing apparatus, and the wet processing apparatus.

According to the substrate processing apparatus of the present invention, the static electricity adjustment section can appropriately control the charge of a substrate, depending on the type of wet processing, for example, by removing static electricity (electric charge) from the substrate or charging the substrate into a desired charged state, so that wet processing can be carried out on the substrate in the appropriately controlled charged state. This can reduce defective processing, thereby increasing the yield of the device.

The present invention also provides a substrate processing method comprising: adjusting static electricity on a substrate; and carrying out wet processing of the static electricity-adjusted substrate.

According to the present invention, static electricity on a surface of the substrate is arbitrarily adjusted prior to carrying out wet processing of the surface of the substrate. This makes it possible to produce an LSI or the like in a high yield even in a future generation when finer interconnects of more advanced material are employed. The present invention can thus contribute to cost reduction of electronic products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1C are diagrams illustrating, in a sequence of process steps, an example of forming copper interconnects;

FIG. 2 is a layout plan view of a conventional substrate processing apparatus for carrying out electroplating;

FIG. 3 is a layout plan view of a substrate processing apparatus, adapted to carry out electroplating, according to an embodiment of the present invention;

FIG. 4 is an enlarged view of the static electricity adjustment section of FIG. 3;

FIG. 5 is a diagram showing a plating apparatus provided with a static electricity adjustment section;

FIG. 6 is a diagram showing another plating apparatus provided with a static electricity adjustment section;

FIG. 7 is a diagram showing a substrate transport robot provided with a static electricity adjustment section;

FIG. 8 is a layout plan view of a substrate processing apparatus, adapted to carry out electroless plating, according to another embodiment of the present invention;

FIG. 9 is a layout plan view of a substrate processing apparatus, adapted to carry out CMP, according to yet another embodiment of the present invention; and

FIG. 10 is a layout plan view of a substrate processing apparatus, adapted to carry out cleaning, according to yet another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the drawings.

FIG. 3 shows a layout plan of a substrate processing apparatus, adapted to carry out electroplating, according to an embodiment of the present invention. The substrate processing apparatus, as with the substrate processing apparatus shown in FIG. 2, includes an apparatus frame 12. A substrate in a dry state is carried into the apparatus frame 12 from a substrate cassette 10; the substrate is processed inside the apparatus frame 12; and the substrate after processing, in a dry state, is taken out of the apparatus frame 12. Inside the apparatus frame 12 are disposed a stage 14, two post-cleaning apparatuses 16, four electroplating apparatuses 20 connected via piping to a plating solution supply/recovery apparatus 18, a first substrate transport robot 22 and a second substrate transport robot 24.

The substrate processing apparatus of this embodiment is also provided with a static electricity adjustment section 30, located in an area surrounded by the first substrate transport robot 22, the stage 14 and one of the post-cleaning apparatuses 16, for detecting the charge of the substrate on the stage 14 and charging the substrate into a charged state suited for wet processing (electroplating).

As shown in detail in FIG. 4, the static electricity adjustment section 30 comprises a static electricity sensor 32, disposed above the substrate W placed on the stage 14, for detecting the charge of the substrate W, and a charging blower 38 as a charging unit, having a motor 34 and a fan 36, which, by the rotation of the fan 36, blows positive or negative ions to the substrate W on the stage 14 so as to charge the substrate W. A detection signal from the static electricity sensor 32 is amplified by an amplifier 40 and the amplified signal is inputted to a control section 42. The rotation speed of the motor 34 of the charging blower 38 is controlled by the output signal of the control section 42, thereby adjusting the charge of the substrate W on the stage 14 to a desired positive or negative charge depending on the rotation speed of the motor 34.

The static electricity sensor 32 and the charging blower 38 may be exemplified by “SK Series” and “SJ-F100/010”, respectively, both manufactured by Keyence Corporation.

According to this embodiment, one substrate W, in a dry state, is taken by the first substrate transport robot 22 out of the substrate cassette 10, and the substrate W is carried into the apparatus frame 12 and placed on the stage 14. The charge of the substrate W on the stage 14 is detected with the static electricity sensor 32. Based on the charge detected, the static electricity adjustment section 30 charges the substrate W on the stage 14 into a desired positively or negatively charged state suited for electroplating using a plating solution (processing liquid) having a large polarity.

Next, the substrate in the thus-adjusted charged state is transported by the second substrate transport robot 24 to the electroplating apparatus 20. In the electroplating apparatus 20, for example, copper is filled into contact holes 3 and interconnect trenches 4, and a copper film 6 is deposited on an insulating film 2, as shown in FIG. 1B. Since the substrate W is in the charged state suited for electroplating using a plating solution (processing liquid) having a large polarity, defective processing due to static electricity, such as deficient metal deposition, uneven metal deposition, etc., can be reduced even in a generation when finer interconnects of more advanced interconnect material are employed.

The substrate W after plating is transported to the post-cleaning apparatus 16 for post-cleaning and drying of the substrate W. The dried substrate W is placed on the stage 14, and is then returned by the first substrate transport robot 22 to the original position in the substrate cassette 10.

FIG. 5 shows another static electricity adjustment section provided in the electroplating apparatus 20. The electroplating apparatus 20 includes a substrate holder 44 which is rotatable and vertically movable, and detachably holds a substrate W with its front surface (surface to be plated) facing downwardly, and a plating tank 48 for holding therein a plating solution (processing liquid) 46. Electroplating of the front surface of the substrate W is carried out by bringing the front surface (lower surface) of the substrate W held by the substrate holder 44 into contact with the plating solution 46 held in the plating tank 48, and applying an electric current.

According to this embodiment, the static electricity adjustment section for removing static electricity (electric charge) from the substrate W is comprised of a conductive wire 50 which is grounded at one end and at the other end is connected to the substrate W held by the substrate holder 44. Thus, according to this embodiment, the substrate W, when held by the substrate holder 44, is grounded via the conductive wire (static electricity adjustment section) 50, whereby static electricity is removed from the substrate W. Accordingly, electroplating of the substrate can be carried out always in the electricity-removed state.

FIG. 6 shows another electroplating apparatus 20. The electroplating apparatus 20 includes a substrate holder 52 for holding a substrate W with its front surface facing upwardly. According to this apparatus, a ring-shaped sealing member 54 is brought into pressure contact with a peripheral portion of the substrate W held by the substrate holder 52 to seal the peripheral portion, and a plating solution 46 is held in the space defined by the upper surface of the substrate W and the sealing member 54 for carrying out plating. Also in this plating apparatus, the substrate W held by the substrate holder 52 is grounded via a conductive wire 56 constituting a static electricity adjustment section. Static electricity is removed from the substrate W when it is held by the substrate holder 52, so that plating of the substrate can be carried out always in the electricity-removed state.

FIG. 7 shows yet another static electricity adjustment section provided, for example, in the first substrate transport robot 22. According to this embodiment, an arm 60 extending from a robot body 58, and a hand 62, positioned at the front end of the arm 60, for placing thereon and holding a substrate W, are both formed of conductive material. The static electricity adjustment section is comprised of a conductive wire 64 which is grounded at one end and at the other end is connected to the robot body 58, so that the conductive wire 64 is electrically connected via the robot body 58 to the arm 60. Thus, according to this embodiment, when the substrate W is held on the hand 62 of the first substrate transport robot 22, the substrate W is grounded via the hand 62, the arm 60, the robot body 58 and the conductive wire 64, whereby static electricity is removed from the substrate W. The substrate W, in the electricity-removed state, is transported to and plated in the electroplating apparatus 20.

It is, of course, possible to provide this static electricity adjustment section in the second substrate transport robot 24. Further, it is possible to use a combination of the static electricity adjustment sections shown in FIGS. 3 and 4, FIG. 5, FIG. 6 and FIG. 7, respectively.

FIG. 8 shows a layout plan of a substrate processing apparatus, adapted to carry out electroless plating, according to another embodiment of the present invention. The substrate processing apparatus includes an apparatus frame 12. A substrate in a dry state is carried into the apparatus frame 12 from a substrate cassette 10; the substrate is processed inside the apparatus frame 12; and the substrate after processing, in a dry state, is taken out of the apparatus frame 12. Inside the apparatus frame 12 are disposed a stage 14, a pre-cleaning apparatus 70, a pretreatment apparatus 72, two electroless plating apparatuses 76 connected via piping to an electroless plating solution supply apparatus 74, a post-cleaning apparatus 78, a drying apparatus 80, a first substrate transport robot 22 and a second substrate transport robot 24. Further, a static electricity adjustment section 30 comprising a static electricity sensor 32 and a charging blower 38, having the same construction as the above-described one, is provided in an area surrounded by the first substrate transport robot 22, the stage 14 and the pre-cleaning apparatus 70.

According to this embodiment, one substrate W, in a dry state, is taken by the first substrate transport robot 22 out of the substrate cassette 10, and the substrate W is carried into the apparatus frame 12 and placed on the stage 14. The charge of the substrate W on the stage 14 is detected with the static electricity sensor 32. Based on the charge detected, the static electricity adjustment section 30 charges the substrate W on the stage 14 into a desired positively or negatively charged state suited for, for example, pretreatment using a pretreatment liquid (processing liquid) or electroless plating using an electroless plating solution (processing liquid).

It is also possible, for example, to charge the substrate by the static electricity adjustment section 30 into a desired positively or negatively charged state suited for pretreatment using a pretreatment liquid (processing liquid), and remove static electricity from the substrate in the electroless plating apparatus 76 by the static electricity adjustment section comprising the conductive wire 50, shown in FIG. 5, or the static electricity adjustment section comprising the conductive wire 56, shown in FIG. 6.

Next, the charge-adjusted substrate is transported by the second substrate transport robot 24 to the pre-cleaning apparatus 70 where the surface of the substrate is pre-cleaned, and the substrate is then transported to the pretreatment apparatus 72 where pretreatment of the surface of the substrate is carried out. Thereafter, the substrate is transported to the electroless plating apparatus 76 where a plated film is formed on the pre-treated surface of the substrate. Thereafter, the substrate is transported to the post-cleaning apparatus 78 where the surface of the substrate is post-cleaned, and the substrate is then transported to the drying apparatus 80 where the substrate is dried. The dried substrate is placed on the stage 14, and is then returned by the first substrate transport robot 22 to the original position in the substrate cassette 10.

Electroless plating involves various wet processings using processing liquids having a large polarity, such as a pretreatment liquid and an electroless plating solution. Therefore, control of the static electricity of a substrate is of especial importance.

FIG. 9 shows a layout plan of a substrate processing apparatus, adapted to carry out CMP, according to yet another embodiment of the present invention. The substrate processing apparatus includes an apparatus frame 12. A substrate in a dry state is carried into the apparatus frame 12 from a substrate cassette 10; the substrate is processed inside the apparatus frame 12; and the substrate after processing, in a dry state, is taken out of the apparatus frame 12. Inside the apparatus frame 12 are disposed a stage 14, a pure water-cleaning apparatus 82, two chemical cleaning apparatuses 84, two CMP apparatuses 88 connected via piping to a polishing liquid supply apparatus 86, a drying apparatus 90, a first substrate transport robot 22 and a second substrate transport robot 24. Further, a static electricity adjustment section 30 comprising a static electricity sensor 32 and a charging blower 38, having the same construction as the above-described one, is provided in an area surrounded by the first substrate transport robot 22, the stage 14 and the pure water-cleaning apparatus 82.

According to this embodiment, one substrate W, in a dry state, is taken by the first substrate transport robot 22 out of the substrate cassette 10, and the substrate W is carried into the apparatus frame 12 and placed on the stage 14. The charge of the substrate W on the stage 14 is detected with the static electricity sensor 32. Based on the charge detected, the charging blower 38 charges the substrate W on the stage 14 into a desired positively or negatively charged state suited for reducing a local cell effect as produced upon polishing materials of different electric potentials, for example, the copper film 6, the barrier layer 5 and the insulating film 2 shown in FIG. 1B.

Next, the charge-adjusted substrate is transported to the CMP apparatus 88. In the CMP apparatus 88, for example, the copper film 6, the seed layer 7 and the barrier layer 5 on the insulating film 2 are removed into a flat surface, as shown in FIGS. 1B and 1C. Since the substrate W is in the charged state suited for CMP, defective processing due to static electricity, such as insufficient polishing, over-polishing, pit formation, corrosion, etc., can be suppressed even in a generation when finer interconnects of more advanced interconnect material are employed.

The substrate after polishing is transported to the chemical cleaning apparatus 84 where the surface of the substrate is cleaned with a liquid chemical (processing liquid), and the substrate is then transported to the pure water-cleaning apparatus 82 where the substrate is cleaned with pure water. Thereafter, the substrate is transported to the drying apparatus 90 where the substrate is dried. The dried substrate is placed on the stage 14, and is then returned by the first substrate transport robot 22 to the original position in the substrate cassette 10.

FIG. 10 shows a layout plan of a substrate processing apparatus, adapted to carry out cleaning, according to yet another embodiment of the present invention. The substrate processing apparatus includes an apparatus frame 12. A substrate in a dry state is carried into the apparatus frame 12 from a substrate cassette 10; the substrate is processed inside the apparatus frame 12; and the substrate after processing, in a dry state, is taken out of the apparatus frame 12. Inside the apparatus frame 12 are disposed a stage 14, two drying apparatuses 92, two back surface-cleaning apparatuses 94, two cleaning apparatuses 98 connected via piping to a cleaning liquid supply apparatus 96, a first substrate transport robot 22 and a second substrate transport robot 24. Further, a static electricity adjustment section 30 comprising a static electricity sensor 32 and a charging blower 38, having the same construction as the above-described one, is provided in an area surrounded by the first substrate transport robot 22, the stage 14 and one of the drying apparatuses 92.

According to this embodiment, one substrate W, in a dry state, is taken by the first substrate transport robot 22 out of the substrate cassette 10, and the substrate W is carried into the apparatus frame 12 and placed on the stage 14. The charge of the substrate W on the stage 14 is detected with the static electricity sensor 32. Based on the charge detected, the charging blower 38 charges the substrate W on the stage 14 into a desired positively or negatively charged state suited for reducing the local cell effect, inhibiting adhesion of particles to the substrate and promoting removal of residual matter from the substrate.

Next, the charge-adjusted substrate is transported to the cleaning apparatus 98, where the surface of the substrate is cleaned with a cleaning liquid (liquid chemical). Since the substrate W is in the charged state suited for cleaning, defective processing due to static electricity, such as poor cleaning, corrosion, etc., can be suppressed even in a generation when finer interconnects of more advanced interconnect material are employed.

The substrate after cleaning is transported to the back surface-cleaning apparatus 94 where the back surface of the substrate is cleaned, and the substrate is then transported to the drying apparatus 92 where the substrate is dried. Thereafter, the dried substrate is placed on the stage 14, and then returned by the first substrate transport robot 22 to the original position in the substrate cassette 10.

Though the above embodiments use an electroplating apparatus, an electroless plating apparatus, a CMP apparatus and a cleaning apparatus as wet processing apparatuses, it is of course possible to use other wet processing apparatuses, such as an electrolytic etching apparatus, an electrolytic polishing apparatus and a chemical etching apparatus.

A description will now be given of an experiment that was conducted to examine the relationship between charge on a substrate and defective processing. In particular, copper electroplating and CMP after the plating of a substrate were carried out in the following cases: without a static electricity treatment of the substrate; after removing static electricity from the substrate; after charging the substrate with a positive charge of +1 kV; and after charging the substrate with a negative charge of −1 kV. In each case, the amount of static electricity on the substrate, the number of defects in copper plating and corrosion upon CMP were measured on the substrate. The results are shown in Table 1.

TABLE 1
Amount of staticNumber of
Static electricityelectricitydefects inCorrosion
treatmenton substratecopper platingupon CMP
No treatment+0.5 kV 5/cm2 3/cm2
Removal of static−0.05 kV <1/cm2<1/cm2
electricity
Positive charge +1 kV+1.1 kV30/cm210/cm2
Negative charge −1 kV−0.9 kV 3/cm2<1/cm2

As will be appreciated from Table 1, the optimum charge value for electroplating does not necessarily coincide with that for CMP. A suitable charge for a substrate may thus differ depending on the type of processing of the substrate. This is considered to be due to different electrolytes or polar compounds employed. Though the mechanism in this regard is not fully elucidated yet and is subject of future investigation, it is clear that control of the static electricity of a substrate can minimize defective processing and can therefore increase the device yield.