BEST MODE FOR CARRYING OUT THE INVENTION

[0060] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0061] FIGS. 1 to 9 show a plating apparatus according to a first embodiment of the present invention. The plating apparatus mainly comprises a substantially cylindrical plating bath 12 for containing a plating liquid 10 therein, a head portion 14 disposed above the plating bath 12 and adapted to hold a substrate W, a drive mechanism 15 for rotating and vertically moving the head portion 14 , and a tilt mechanism 16 for tilting the head portion 14 and the drive mechanism 15 integrally. FIG. 1 shows the plating apparatus lying at a plating position at which the head portion 14 is lowered and an overflow surface (liquid level) 10 a of the plating liquid 10 is raised.

[0062] The plating bath 12 has a plating chamber 18 opening upward and having a flat plate-shaped anode 17 disposed horizontally at the bottom thereof. On the inner peripheral wall of the plating bath 12 , plating liquid ejection nozzles 20 horizontally protruding toward the center of the plating chamber 18 are arranged at equal intervals along the circumferential direction. These plating liquid ejection nozzles 20 communicate with a plating liquid supply passage (not shown) extending vertically within the plating bath 12 . The plating liquid ejection nozzles 20 may be inclined upwardly protruding toward the center of the plating chamber 18 .

[0063] In this embodiment, moreover, a punched plate 22 formed many holes, for example, of about 3 mm is disposed in the plating chamber 18 at a position above the anode 17 to thereby prevent a black film, which is formed on the surface of the anode 17 , from being brought up by the flow of the plating liquid 10 and flowed out.

[0064] The plating bath 12 is also provided with a first plating liquid discharge port 24 for pulling out the plating liquid 10 in the plating chamber 18 from the peripheral edge of the bottom of the plating chamber 18 , and a second plating liquid discharge port 30 (see FIGS. 7A and 7B ) designed to discharge the plating liquid 10 , which has overflowed an overflow weir 28 for dividing the interior of the plating bath 12 into the plating chamber 18 and an overflow channel 26 , and to discharge the plating liquid 10 before overflowing the overflow weir 28 . In a lower portion of the overflow weir 28 , openings 28 a with a predetermined width are provided at predetermined intervals along the circumferential direction in order to discharge the plating liquid 10 before overflowing the overflow weir 28 to the second plating liquid discharge port 30 , as shown in FIGS. 7A to 7 C.

[0065] Because of this structure, when the amount of a plating liquid supplied is large during plating process, the plating liquid is caused to overflow the overflow weir 28 , and further passed through the openings 28 a for discharging to the outside through the second plating liquid discharge port 30 , as shown in FIG. 7A . When the amount of a plating liquid supplied is small during plating process, the plating liquid is passed through the openings 28 a and discharged to the outside through the second plating liquid discharge port 30 , as shown in FIG. 7B . These contrivances permit easy adaptation to the magnitude of the amount of a plating liquid. The plating liquid present between a shielding plate and the overflow weir 28 when the liquid level of the plating liquid is lowered can be withdrawn through the openings 28 a.

[0066] Furthermore, as shown in FIG. 7 D, through-holes 32 for liquid level control, which communicate with the plating chamber 18 and the second plating liquid discharge port 30 , are provided above the plating liquid ejection nozzles 20 and with a predetermined pitch along the circumferential direction. Thus, the plating liquid is passed through the through-holes 32 in a non-plating process to be discharged to the outside through the second plating liquid discharge port 30 , whereby the liquid level of the plating liquid in the plating chamber 18 is controlled. These through-holes 32 play the role of orifices during plating process to restrict the amount of the plating liquid flowing out therethrough.

[0067] Near the periphery of the interior of the plating chamber 18 , a flow adjusting ring 34 of a hook-shaped cross section is disposed by having the outer peripheral end thereof secured to the plating bath 12 . The flow adjusting ring 34 serves to push up the center of the plating liquid surface by an upper flow of the plating liquid 10 divided into upper and lower flows in the plating chamber 18 , to smooth the lower flow, and make the distribution of an electric current density more uniform.

[0068] The head portion 14 comprises a rotatable, bottomed, cylindrical housing 36 opening downward and having openings 36 a in a circumferential wall thereof, and vertically movable press rods 40 attached to a press ring 38 at the lower end thereof. A ring-shaped substrate holding portion 42 protruding inwardly is provided at the lower opened end of the housing 36 , as shown in FIG. 6 . A ring-shaped seal member 44 , which protrudes inwardly and has an upper surface projecting upward at the front end in the shape of a pinnacle, is attached to the substrate holding portion 42 . Cathode electrode contacts 46 are disposed above the seal member 44 . In the substrate holding portion 42 , air vent holes 48 , which extend outwardly in a horizontal direction and further extend upwardly obliquely toward the outside, are provided at equal intervals along the circumferential direction. The air vent holes 48 can inhibit air bubbles from remaining on the surface of the substrate. Decreasing the thickness of the seal member 44 and the substrate holding portion 42 can also ensure similar air venting properties. The air venting properties are also governed by the material for the substrate holding portion, and a smooth, water repellent material, such as Teflon, is preferably used as the substrate holding portion.

[0069] With the liquid level of the plating liquid 10 in the plating chamber 18 being lowered, the substrate W is held and put into the housing 36 by an attraction hand H or the like so as to place on the upper surface of the seal member 44 of the substrate holding portion 42 . After the attraction hand H is pulled out of the housing 36 , the press ring 38 is lowered to hold the substrate W while sandwiching a peripheral edge portion of the substrate W between the seal member 44 and the lower surfaces of the press ring 48 , as shown in FIGS. 5 and 6 . When the substrate W is held in this manner, the lower surface of the substrate W and the seal member 44 are brought into pressed contact to achieve reliable sealing there. At the same time, a seed layer 7 (see FIG. 10A ) formed on the surface of the substrate W and the cathode electrode contacts 46 are brought into contact to pass an electric current therethrough, so that the seed layer 7 becomes a cathode.

[0070] A rotating motor 50 is provided in the drive mechanism 15 . The housing 36 is connected to an output shaft 52 of the motor 50 , and is adapted to rotate by driving of the motor 50 . The press rods 40 are positioned vertically at predetermined positions along the circumferential direction of a ring-shaped support frame 60 rotatably supported via a bearing 58 at the lower end of a slider 56 movable vertically by the actuation of a guide-equipped cylinder 54 secured to the motor 50 . Thus, the press rods 40 move vertically according to the actuation of the cylinder 54 , and when the substrate W is held, are adapted to rotate integrally with the housing 36 .

[0071] A connector 62 is mounted on the outer peripheral surface of the rotating motor 50 . A slide base 68 , which is screwed to a ball screw 66 rotating in accordance with the driving of an elevating motor 64 so as to move vertically together with, is attached to the connector 62 . Thus, the rotating motor 50 and the head portion 14 are moved up and down integrally in accordance with the driving of the elevating motor 64 .

[0072] Crystals of the plating liquid easily deposit on the inner peripheral surface of the overflow weir 28 . If a large amount of the plating liquid is flowed, with the head portion 14 and the drive mechanism 15 being raised, to cause an overflow over the overflow weir 28 , deposition of crystals of the plating liquid on the inner peripheral surface of the overflow weir 28 can be prevented.

[0073] Above the substrate holding portion 42 of the housing 36 , a substrate centering mechanism 70 for performing centering of the substrate W is provided at each of four sites along the circumferential direction in this embodiment. FIG. 8 shows details of the substrate centering mechanism 70 , which includes a gate-shaped bracket 72 fixed to the housing 36 , and a positioning block 74 placed within the bracket 72 . The positioning block 74 has an upper portion pivotably supported by a pivot shaft 76 horizontally fixed to the bracket 72 , and a helical compression spring 78 is interposed between the housing 36 and the positioning block 74 . Thus, the positioning block 74 is urged via the helical compression spring 78 such that its lower portion protrudes inwardly about the pivot shaft 76 , while its upper surface 74 a contacts a lower surface 72 a of an upper portion of the bracket 72 to play the role of a stopper, whereby the movement of the positioning block 74 is restrained. Furthermore, the inner surface of the positioning block 74 makes a taper surface 74 b fanning out upwardly.

[0074] When the substrate is held and transferred by an attraction hand, such as a transfer robot, into the housing 36 to place on the substrate holding portion 42 , the center of the substrate may be displaced from the center of the substrate holding portion 42 . In this case, the positioning block 74 pivots outward in opposition to the elastic force of the helical compression spring 78 . On this occasion, when the grasp by the attraction hand such as carrier robot is released, the positioning block 74 returns to the original position under the elastic force of the helical compression spring 78 , whereby centering of the substrate can take place.

[0075] FIG. 9 shows a power supply contact (probe) 82 for supplying power to a cathode electrode plate 80 of the cathode electrode contact 46 . The power supply contact 82 is composed of a plunger, and surrounded by a cylindrical protector 84 reaching to the cathode electrode plate 80 , and thereby protected from the plating liquid.

[0076] The tilt mechanism 16 includes rests 86 erected with predetermined spacing on a floor surface, a tilt stand 90 , which consists of two uprights connected by a third member at the bottom, connected to the rests 86 so as to be tiltable about pivot shafts 88 as fulcrums of rotation, and a tilt cylinder 92 extending between on the side of the rests 86 and the side of the tilt stand 90 . A base plate 94 is fastened to the upper surface of the tilt stand 90 , and the drive mechanism 15 is mounted on the base plate 94 . Thus, according to the actuation of the tilt cylinder 92 , the tilt stand 90 tilts about the pivot shafts 88 . According to the tilt of the tilt stand 90 , the head portion 14 and the drive mechanism 15 tilt integrally.

[0077] That is, the plating apparatus can be in two states, an upright state and a tilt state. In the upright state, as shown in FIG. 1 , the output shaft 52 of the rotating motor 50 of the drive mechanism 15 and the ball screw 66 both head in a vertical direction, the head portion 14 holds the substrate W horizontally, and the substrate W can be rotated and raised or lowered in this horizontal state. In the tilt state, as shown in FIGS. 3 and 4 , the output shaft 52 of the rotating motor 50 of the drive mechanism 15 and the ball screw 66 both tilt at a tilt angle α with respect to the vertical direction, the head portion 14 holds the substrate W in an inclined manner at the tilt angle α with respect to the horizontal plane, and in this inclined state the substrate W can be rotated about the axis of the output shaft 52 of the rotating motor 50 and raised or lowered along this axis. The tilt angle α is preferably ranging from 2° to 10°, and is set at 20° 30′ in this embodiment.

[0078] The pivot shafts 88 are disposed so as to be located in substantially the same plane as a plane formed by the overflow surface (liquid surface) 10 a of the plating liquid 10 held in the plating bath 12 . By this arrangement, the range in which the head portion 14 and the drive mechanism 15 tilt is maximally narrowed to achieve the small, compact size of the plating apparatus.

[0079] A stopper 96 is provided on the side of the floor surface, while a stopper piece 98 is provided on the side of the tilt stand 90 , respectively. When the output shaft 52 of the rotating motor 50 of the drive mechanism 15 and the ball screw 66 both head in the vertical direction and stand in the upright state, the stopper piece 98 contacts the stopper 96 , maintaining this state and keeping the tilt stand 90 from tilting in the reverse direction.

[0080] Next will follow a description of plating process by the plating apparatus as plating with copper or its alloy for the formation of an interconnection circuit on a semiconductor substrate. In a substrate W as an object to be treated, as shown in FIG. 10A, a conductive layer 1 a , and an insulating film 2 of SiO ₂ are deposited on a semiconductor substrate 1 having a semiconductor circuit device formed therein. Then, a contact hole 3 and a trench 4 for an interconnection are formed in the insulating film 2 by lithography and etching technology, and a barrier layer 5 of TaN or the like and a copper seed layer 7 are formed thereon.

[0081] When the substrate W is transferred to the plating apparatus, the substrate W held in such a state that the surface of the substrate W face downwardly by attraction hand is inserted into the housing 36 through its opening 36 a , in the plating position with the head portion 14 being lowered as shown in FIG. 1 . The attraction hand is moved downward, and then vacuum attraction is released to place the substrate W on the substrate holding portion 42 of the housing 36 . Then, the attraction hand is raised and withdrawn from the housing 36 . Then, the press ring 38 is lowered to sandwich the peripheral edge portion of the substrate W between the substrate holding portion 42 and the lower surfaces of the press ring 38 and hold the substrate W horizontally.

[0082] Then, as shown in FIG. 3 , the elevating motor 64 of the drive mechanism 15 is driven to raise the head portion 14 , and the tilt cylinder 92 is actuated to tilt the head portion 14 and the drive mechanism 15 integrally such that the output shaft 52 of the rotating motor 50 and the ball screw 66 incline at the tilt angle α to the vertical direction.

[0083] In the plating bath 12 , the plating liquid in a relatively large volume of, for example, about 5 to 30 L/min, preferably about 15 to 25 L/min is ejected through the plating liquid ejection nozzles 20 to raise the liquid level of the plating liquid 10 and to form upwardly bulging flows of the plating liquid in the plating liquid 10 within the plating chamber 18 . The plating liquid 10 which has overflowed the plating chamber 18 is recovered through the overflow channel 26 .

[0084] In this state, the substrate W held obliquely relative to the horizontal plane, as shown in FIG. 4 , is rotated about the axis of the rotating motor 50 at a rotational speed of, for example, about 10 to 250 rpm, preferably abut 40 to 200 rpm, and lowered along this axis at a speed of, for example, about 10 to 250 mm/sec, preferably 50 mm/sec, with a plating electric current being passed between the anode 17 and the seed layer 7 , as the cathode, formed on the surface of the substrate W. If the rotational speed of the substrate is less than 10 rpm, the effect of suppressing remaining air bubbles declines. If the rotational speed of the substrate is higher than 250 rpm, the plating liquid froths up. More preferably, the rotational speed of the substrate is 100 to 200 rpm. As the lowering speed of the substrate increases, the time required for contact of the substrate with the plating liquid can be shortened, and the formation of a uniform film becomes easier. However, too high a lowering speed results in the upsizing of the plating apparatus.

[0085] The lower surface (the surface to be plated) of the substrate W first contacts a central part of the bulgy overflow surface (liquid surface) 10 a formed by flows of the plating liquid, and further descends. Since the substrate W contacts the overflow surface 10 a of the plating liquid in a state that the substrate is inclined relative to the horizontal plane, resistance which the substrate W receives from the plating liquid during descent of the substrate is reduced. Thus, this operation takes place smoothly. Furthermore, the area of contact gradually spreads outward. At the same time, a centrifugal force associated with the rotation of the substrate W works, whereby air bubbles below the surface to be plated are discharged to the outside.

[0086] After more than a half of the substrate W is immersed in the plating liquid 10 , the tilt cylinder 92 is actuated in a manner contrary to the above-described manner, with the substrate W being raised or not being raised. By this procedure, the substrate W in an inclined state relative to the horizontal plane is returned to the horizontal state, namely, the state shown in FIG. 1 , whereby the entire surface, to be plated, of the substrate W is immersed in the plating liquid 10 . This operation is performed smoothly like the aforementioned operation, and air bubbles below the surface, to be plated, of the substrate are also discharged to the outside.

[0087] This state is maintained for a predetermined period of time, and plating process is completed. After energization is stopped, the amount of the plating liquid supplied is decreased so that the plating liquid flows to the outside through the first plating liquid discharge port 24 and the second plating liquid discharge port 30 communicating with the through-holes 32 for liquid level control which are located above the plating liquid ejection nozzles 20 , as shown in FIG. 7D . By this manner, the head portion 14 and the substrate W held thereby are exposed above the surface of the plating liquid. With the head portion 14 and the substrate W held thereby being situated above the surface of the plating liquid, the head portion 14 and the substrate W are rotated at a high speed (e.g., 500 to 800 rpm) to dehydrate the plating liquid by a centrifugal force. After the dehydration of the plating liquid is completed, the housing 36 is pointed in a predetermined direction, and the rotation of the head portion 14 is stopped.

[0088] By the above-described plating process, copper is filled into the contact hole 3 and the trench 4 of the semiconductor substrate W, as shown in FIG. 10B . Then, a copper film 6 and the barrier layer 5 deposited on the insulating film 2 is removed by chemical mechanical polishing (CMP), thus making the surface of the copper film 6 filled into the contact hole 3 and the trench 4 for an interconnection lie flush with the surface of the insulating film 2 . In this manner, an interconnection composed of the copper film 6 is formed as shown in FIG. 10C .

[0089] After the head portion 14 is completely stopped, the press ring 38 is raised. Then, the attraction hand is inserted into the housing 36 through its opening 36 a , with the attraction surface of the attraction hand facing downward. The attraction hand is lowered to a position at which the attraction hand can attract the substrate. The substrate is vacuum attracted by the attraction hand, and the attraction hand is moved to a position the upper position of the opening 36 a of the housing 36 , whereupon the attraction hand and the substrate held thereby are taken out through the opening 36 a of the housing 36 .

[0090] According to this embodiment, energization can be started based on the time when the descent of the head portion 14 is initiated. Thus, completion of contact with the plating liquid and start of energization can be performed with close timings, thus preventing etching of the seed layer due to its contact with the plating liquid during a period without energization. Hence, the filling properties of the resulting pattern and the uniformity of the film are improved. Furthermore, the speed of contact of the substrate W with the plating liquid is so high that the difference in time between the start of contact with the plating liquid and the completion of contact with the plating liquid is decreased. Because of this advantage as well, the filling properties and the film uniformity are improved.

[0091] FIG. 11 shows a plating apparatus according to a second embodiment of the present invention. The plating apparatus is configured such that a rotating motor 50 of a drive mechanism 15 is disposed, with an output shaft 52 of the rotating motor 50 being inclined at an angle of β with respect to a vertical direction. By this arrangement, a substrate W is held by a housing 36 of a head portion 14 so as to be inclined at an angle of β with respect to the horizontal plane. In agreement with this angle β, an anode 17 placed within a plating bath 12 is also inclined at an angle of β with respect to the horizontal plane so as to be parallel to the substrate W held by the housing 36 . This angle β is desirably ranging from 1° to 10°, and set at 3° in the present embodiment. The drive mechanism 15 is provided with an elevating device (not shown) for moving vertically the head portion 14 along the axis of the output shaft 52 of the rotating motor 50 . Other features are substantially the same as in the first embodiment.

[0092] An example of usage of this plating apparatus will be described with reference to FIGS. 12A to 12 F.

[0093] The substrate W, with its surface to be plated facing downward, is inserted into and held in the housing 36 , in the plating position with the head portion 14 being lowered as shown in FIG. 12A . Then, the head portion 14 is raised by, for example, about 20 to 30 mm, as shown in FIG. 12B . Then, a plating liquid 10 is poured into a plating chamber 18 of a plating bath 12 to raise the liquid level of the plating liquid and stabilize the plating liquid at a flow rate during plating process.

[0094] In this state, the substrate W is rotated and lowered via the head portion 14 , as shown in FIG. 12 C, with a plating electric current being passed between the anode 17 and a seed layer 7 , as the cathode, formed on the surface of the substrate W. When the substrate W descends to the plating position shown in FIG. 12 D, descent of the substrate is stopped. During descent of the substrate W to the plating position, a central part of its surface to be plated contacts the overflow surface (liquid surface) 10 a of the plating liquid 10 . While air bubbles below the surface, to be plated, of the substrate is being removed, the area of this contact gradually spreads outward. At a time when the substrate W contacts the overflow surface (liquid surface) 10 a of the plating liquid 10 , an electric current flows so that plating process starts.

[0095] Upon completion of plating process, the supply of the electric current is stopped, and the liquid level of the plating liquid 10 is lowered to expose the substrate W above the plating liquid, as shown in FIG. 12E . The substrate W is rotated at a high speed to dehydrate the plating liquid. Then, the substrate W after the dehydration of the plating liquid is withdrawn from the housing 36 by a robot hand, as shown in FIG. 12F .

[0096] According to the present invention, as described above, the surface, to be plated, of the substrate is inclined relative to the overflow surface of the plating liquid while the surface to be plated is contacting the plating liquid. By this manner, the contact of the plating liquid with the surface, to be plated, of the substrate can be made smoothly, and this operation can be performed promptly. Furthermore, air bubbles can be inhibited from remaining on the surface, to be plated, of the substrate, whereby defects, such as a deficiency in the plated film, can be prevented.

[0097] In the above embodiments, although copper is used as plating material to fill into the contact hole and the trench, other metal such as silver and its alloy may be used as plating material. Furthermore, this plating apparatus is adapted to form a metal layer on the substrate, and to conduct electroless-plating process.

[0098] FIG. 14 is a plan view of an example of a substrate plating apparatus. The substrate plating apparatus comprises loading/unloading sections 510 , each pair of cleaning/drying sections 512 , first substrate stages 514 , bevel-etching/chemical cleaning sections 516 and second substrate stages 518 , a washing section 520 provided with a mechanism for reversing the substrate through 180°, and four plating apparatuses 522 . The plating substrate apparatus is also provided with a first transporting device 524 for transporting a substrate between the loading/unloading sections 510 , the cleaning/drying sections 512 and the first substrate stages 514 , a second transporting device 526 for transporting a substrate between the first substrate stages 514 , the bevel-etching/chemical cleaning sections 516 and the second substrate stages 518 , and a third transporting device 528 for transporting the substrate between the second substrate stages 518 , the washing section 520 and the plating apparatuses 522 .

[0099] The substrate plating apparatus has a partition wall 523 for dividing the plating apparatus into a plating space 530 and a clean space 540 . Air can individually be supplied into and exhausted from each of the plating space 530 and the clean space 540 . The partition wall 523 has a shutter (not shown) capable of opening and closing. The pressure of the clean space 540 is lower than the atmospheric pressure and higher than the pressure of the plating space 530 . This can prevent the air in the clean space 540 from flowing out of the plating apparatus and can prevent the air in the plating space 530 from flowing into the clean space 540 .

[0100] FIG. 15 is a schematic view showing an air current in the plating substrate apparatus. In the clean space 540 , a fresh external air is introduced through a pipe 543 and pushed into the clean space 540 through a high-performance filter 544 by a fan. Hence, a down-flow clean air is supplied from a ceiling 545 a to positions around the cleaning/drying sections 512 and the bevel-etching/chemical cleaning sections 516 . A large part of the supplied clean air is returned from a floor 545 b through a circulation pipe 552 to the ceiling 545 a , and pushed again into the clean space 540 through the high-performance filter 544 by the fan, to thus circulate in the clean space 540 . A part of the air is discharged from the cleaning/drying sections 512 and the bevel-etching/chemical cleaning sections 516 through a pipe 546 to the exterior, so that the pressure of the clean space 540 is set to be lower than the atmospheric pressure.

[0101] The plating space 530 having the washing sections 520 and the plating apparatuses 522 therein is not a clean space (but a contamination zone). However, it is not acceptable to attach particles to the surface of the substrate. Therefore, in the plating space 530 , a fresh external air is introduced through a pipe 547 , and a down-flow clean air is pushed into the plating space 530 through a high-performance filter 548 by a fan, for thereby preventing particles from being attached to the surface of the substrate. However, if the whole flow rate of the down-flow clean air is supplied by only an external air supply and exhaust, then enormous air supply and exhaust are required. Therefore, the air is discharged through a pipe 553 to the exterior, and a large part of the down-flow is supplied by a circulating air through a circulation pipe 550 extended from a floor 549 b , in such a state that the pressure of the plating space 530 is maintained to be lower than the pressure of the clean space 540 .

[0102] Thus, the air returned to a ceiling 549 a through the circulation pipe 550 is pushed again into the plating space 530 through the high-performance filter 548 by the fan. Hence, a clean air is supplied into the plating space 530 to thus circulate in the plating space 530 . In this case, air containing chemical mist or gas emitted from the washing sections 520 , the plating sections 522 , the third transporting device 528 , and a plating liquid regulating tank 551 is discharged through the pipe 553 to the exterior. Thus, the pressure of the plating space 530 is controlled so as to be lower than the pressure of the clean space 540 .

[0103] The pressure in the loading/unloading sections 510 is higher than the pressure in the clean space 540 which is higher than the pressure in the plating space 530 . When the shutters (not shown) are opened, therefore, air flows successively through the loading/unloading sections 510 , the clean space 540 , and the plating space 530 , as shown in FIG. 16 . Air discharged from the clean space 540 and the plating space 530 flows through the ducts 552 , 553 into a common duct 554 (see FIG. 17 ) which extends out of the clean room.

[0104] FIG. 17 shows in perspective the substrate plating apparatus shown in FIG. 14 , which is placed in the clean room. The loading/unloading sections 510 includes a side wall which has a cassette transfer port 555 defined therein and a control panel 556 , and which is exposed to a working zone 558 that is compartmented in the clean room by a partition wall 557 . The partition wall 557 also compartments a utility zone 559 in the clean room in which the substrate plating apparatus is installed. Other sidewalls of the substrate plating apparatus are exposed to the utility zone 559 whose air cleanness is lower than the air cleanness in the working zone 558 .

[0105] FIG. 18 is a plan view of another example of a substrate plating apparatus. The substrate plating apparatus shown in FIG. 18 comprises a loading unit 601 for loading a semiconductor substrate, a copper plating chamber 602 for plating a semiconductor substrate with copper, a pair of water cleaning chambers 603 , 604 for cleaning a semiconductor substrate with water, a chemical mechanical polishing unit 605 for chemically and mechanically polishing a semiconductor substrate, a pair of water cleaning chambers 606 , 607 for cleaning a semiconductor substrate with water, a drying chamber 608 , for drying a semiconductor substrate, and an unloading unit 609 for unloading a semiconductor substrate with an interconnection film thereon. The substrate plating apparatus also has a substrate transfer mechanism (not shown) for transferring semiconductor substrates to the chambers 602 , 603 , 604 , the chemical mechanical polishing unit 605 , the chambers 606 , 607 , 608 , and the unloading unit 609 . The loading unit 601 , the chambers 602 , 603 , 604 , the chemical mechanical polishing unit 605 , the chambers 606 , 607 , 608 , and the unloading unit 609 are combined into a single unitary arrangement as apparatus.

[0106] The substrate plating apparatus operates as follows: The substrate transfer mechanism transfers a semiconductor substrate W on which an interconnection film has not yet been formed from a substrate cassette 601 - 1 placed in the loading unit 601 to the copper plating chamber 602 . In the copper plating chamber 602 , a plated copper film is formed on a surface of the semiconductor substrate W having an interconnection region composed of an interconnection trench and an interconnection hole (contact hole).

[0107] After the plated copper film is formed on the semiconductor substrate W in the copper plating chamber 602 , the semiconductor substrate W is transferred to one of the water cleaning chambers 603 , 604 by the substrate transfer mechanism and cleaned by water in one of the water cleaning chambers 603 , 604 . The cleaned semiconductor substrate W is transferred to the chemical mechanical polishing unit 605 by the substrate transfer mechanism. The chemical mechanical polishing unit 605 removes the unwanted plated copper film from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole. A barrier layer made of TiN or the like is formed on the surface of the semiconductor substrate W, including the inner surfaces of the interconnection trench and the interconnection hole, before the plated copper film is deposited.

[0108] Then, the semiconductor substrate W with the remaining plated copper film is transferred to one of the water cleaning chambers 606 , 607 by the substrate transfer mechanism and cleaned by water in one of the water cleaning chambers 607 , 608 . The cleaned semiconductor substrate W is then dried in the drying chamber 608 , after which the dried semiconductor substrate W with the remaining plated copper film serving as an interconnection film is placed into a substrate cassette 609 - 1 in the unloading unit 609 .

[0109] FIG. 19 shows a plan view of still another example of a substrate plating apparatus. The substrate plating apparatus shown in FIG. 19 differs from the substrate plating apparatus shown in FIG. 18 in that it additionally includes a copper plating chamber 602 , a water cleaning chamber 610 , a pretreatment chamber 611 , a protective layer plating chamber 612 for forming a protective plated layer on a plated copper film on a semiconductor substrate, water cleaning chamber 613 , 614 , and a chemical mechanical polishing unit 615 . The loading unit 601 , the chambers 602 , 602 , 603 , 604 , 614 , the chemical mechanical polishing unit 605 , 615 , the chambers 606 , 607 , 608 , 610 , 611 , 612 , 613 , and the unloading unit 609 are combined into a single unitary arrangement as an apparatus.

[0110] The substrate plating apparatus shown in FIG. 19 operates as follows: A semiconductor substrate W is supplied from the substrate cassette 601 - 1 placed in the loading unit 601 successively to one of the copper plating chambers 602 , 602 . In one of the copper plating chamber 602 , 602 , a plated copper film is formed on a surface of a semiconductor substrate W having an interconnection region composed of an interconnection trench and an interconnection hole (contact hole). The two copper plating chambers 602 , 602 are employed to allow the semiconductor substrate W to be plated with a copper film for a long period of time. Specifically, the semiconductor substrate W may be plated with a primary copper film according to electroless-plating in one of the copper plating chamber 602 , and then plated with a secondary copper film according to electroplating in the other copper plating chamber 602 . The substrate plating apparatus may have more than two copper plating chambers.

[0111] The semiconductor substrate W with the plated copper film formed thereon is cleaned by water in one of the water cleaning chambers 603 , 604 . Then, the chemical mechanical polishing unit 605 removes the unwanted portion of the plated copper film from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole.

[0112] Thereafter, the semiconductor substrate W with the remaining plated copper film is transferred to the water cleaning chamber 610 , in which the semiconductor substrate W is cleaned with water. Then, the semiconductor substrate W is transferred to the pretreatment chamber 611 , and pretreated therein for the deposition of a protective plated layer. The pretreated semiconductor substrate W is transferred to the protective layer-plating chamber 612 . In the protective layer plating chamber 612 , a protective plated layer is formed on the plated copper film in the interconnection region on the semiconductor substrate W. For example, the protective plated layer is formed with an alloy of nickel (Ni) and boron (B) by electroless-plating.

[0113] After semiconductor substrate is cleaned in one of the water cleaning chamber 613 , 614 , an upper portion of the protective plated layer deposited on the plated copper film is polished off to planarize the protective plated layer, in the chemical mechanical polishing unit 615 ,

[0114] After the protective plated layer is polished, the semiconductor substrate W is cleaned by water in one of the water cleaning chambers 606 , 607 , dried in the drying chamber 608 , and then transferred to the substrate cassette 609 - 1 in the unloading unit 609 .

[0115] FIG. 20 is a plan view of still another example of a substrate plating apparatus. As shown in FIG. 20 , the substrate plating apparatus includes a robot 616 at its center which has a robot arm 616 - 1 , and also has a copper plating chamber 602 , a pair of water cleaning chambers 603 , 604 , a chemical mechanical polishing unit 605 , a pretreatment chamber 611 , a protective layer plating chamber 612 , a drying chamber 608 , and a loading/unloading station 617 which are disposed around the robot 616 and positioned within the reach of the robot arm 616 - 1 . A loading unit 601 for loading semiconductor substrates and an unloading unit 609 for unloading semiconductor substrates is disposed adjacent to the loading/unloading station 617 . The robot 616 , the chambers 602 , 603 , 604 , the chemical mechanical polishing unit 605 , the chambers 608 , 611 , 612 , the loading/unloading station 617 , the loading unit 601 , and the unloading unit 609 are combined into a single unitary arrangement as an apparatus.

[0116] The substrate plating apparatus shown in FIG. 20 operates as follows:

[0117] A semiconductor substrate to be plated is transferred from the loading unit 601 to the loading/unloading station 617 , from which the semiconductor substrate is received by the robot arm 616 - 1 and transferred thereby to the copper plating chamber 602 . In the copper plating chamber 602 , a plated copper film is formed on a surface of the semiconductor substrate which has an interconnection region composed of an interconnection trench and an interconnection hole. The semiconductor substrate with the plated copper film formed thereon is transferred by the robot arm 616 - 1 to the chemical mechanical polishing unit 605 . In the chemical mechanical polishing unit 605 , the plated copper film is removed from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole.

[0118] The semiconductor substrate is then transferred by the robot arm 616 - 1 to the water-cleaning chamber 604 , in which the semiconductor substrate is cleaned by water. Thereafter, the semiconductor substrate is transferred by the robot arm 616 - 1 to the pretreatment chamber 611 , in which the semiconductor substrate is pretreated therein for the deposition of a protective plated layer. The pretreated semiconductor substrate is transferred by the robot arm 616 - 1 to the protective layer plating chamber 612 . In the protective layer plating chamber 612 , a protective plated layer is formed on the plated copper film in the interconnection region on the semiconductor substrate W. The semiconductor substrate with the protective plated layer formed thereon is transferred by the robot arm 616 - 1 to the water cleaning chamber 604 , in which the semiconductor substrate is cleaned by water. The cleaned semiconductor substrate is transferred by the robot arm 616 - 1 to the drying chamber 608 , in which the semiconductor substrate is dried. The dried semiconductor substrate is transferred by the robot arm 616 - 1 to the loading/unloading station 617 , from which the plated semiconductor substrate is transferred to the unloading unit 609 .

[0119] FIG. 21 is a view showing the plan constitution of another example of a semiconductor substrate processing apparatus. The semiconductor substrate processing apparatus is of a constitution in which there are provided a loading/unloading section 701 , a plated Cu film forming unit 702 , a first robot 703 , a third cleaning machine 704 , a reversing machine 705 , a reversing machine 706 , a second cleaning machine 707 , a second robot 708 , a first cleaning machine 709 , a first polishing apparatus 710 , and a second polishing apparatus 711 . A before-plating and after-plating film thickness measuring instrument 712 for measuring the film thicknesses before and after plating, and a dry state film thickness measuring instrument 713 for measuring the film thickness of a semiconductor substrate W in a dry state after polishing are placed near the first robot 703 .

[0120] The first polishing apparatus (polishing unit) 710 has a polishing table 710 - 1 , a top ring 710 - 2 , a top ring head 710 - 3 , a film thickness measuring instrument 710 - 4 , and a pusher 710 - 5 . The second polishing apparatus (polishing unit) 711 has a polishing table 711 - 1 , a top ring 711 - 2 , a top ring head 711 - 3 , a film thickness measuring instrument 711 - 4 , and a pusher 711 - 5 .

[0121] A cassette 701 - 1 accommodating the semiconductor substrates W, in which a via hole and a trench for interconnect are formed, and a seed layer is formed thereon is placed on a loading port of the loading/unloading section 701 . The first robot 703 takes out the semiconductor substrate W from the cassette 701 - 1 , and carries the semiconductor substrate W into the plated Cu film forming unit 702 where a plated Cu film is formed. At this time, the film thickness of the seed layer is measured with the before-plating and after-plating film thickness measuring instrument 712 . The plated Cu film is formed by carrying out hydrophilic treatment of the face of the semiconductor substrate W, and then Cu plating. After formation of the plated Cu film, rinsing or cleaning of the semiconductor substrate W is carried out in the plated Cu film forming unit 702 .

[0122] When the semiconductor substrate W is taken out from the plated Cu film forming unit 702 by the first robot 703 , the film thickness of the plated Cu film is measured with the before-plating and after-plating film thickness measuring instrument 712 . The results of its measurement are recorded into a recording device (not shown) as record data on the semiconductor substrate, and are used for judgment of an abnormality of the plated Cu film forming unit 702 . After measurement of the film thickness, the first robot 703 transfers the semiconductor substrate W to the reversing machine 705 , and the reversing machine 705 reverses the semiconductor substrate W (the surface on which the plated Cu film has been formed faces downward). The first polishing apparatus 710 and the second polishing apparatus 711 perform polishing in a serial mode and a parallel mode. Next, polishing in the serial mode will be described.

[0123] In the serial mode polishing, a primary polishing is performed by the polishing apparatus 710 , and a secondary polishing is performed by the polishing apparatus 711 . The second robot 708 picks up the semiconductor substrate W on the reversing machine 705 , and places the semiconductor substrate W on the pusher 710 - 5 of the polishing apparatus 710 . The top ring 710 - 2 attracts the semiconductor substrate W on the pusher 710 - 5 by suction, and brings the surface of the plated Cu film of the semiconductor substrate W into contact with a polishing surface of the polishing table 710 - 1 under pressure to perform a primary polishing. With the primary polishing, the plated Cu film is basically polished. The polishing surface of the polishing table 710 - 1 is composed of foamed polyurethane such as IC1000, or a material having abrasive grains fixed thereto or impregnated therein. Upon relative movements of the polishing surface and the semiconductor substrate W, the plated Cu film is polished.

[0124] After completion of polishing of the plated Cu film, the semiconductor substrate W is returned onto the pusher 710 - 5 by the top ring 710 - 2 . The second robot 708 picks up the semiconductor substrate W, and introduces it into the first cleaning machine 709 . At this time, a chemical liquid may be ejected toward the face and backside of the semiconductor substrate W on the pusher 710 - 5 to remove particles therefrom or cause particles to be difficult to adhere thereto.

[0125] After completion of cleaning in the first cleaning machine 709 , the second robot 708 picks up the semiconductor substrate W, and places the semiconductor substrate W on the pusher 711 - 5 of the second polishing apparatus 711 . The top ring 711 - 2 attracts the semiconductor substrate W on the pusher 711 - 5 by suction, and brings the surface of the semiconductor substrate W, which has the barrier layer formed thereon, into contact with a polishing surface of the polishing table 711 - 1 under pressure to perform the secondary polishing. The constitution of the polishing table is the same as the top ring 711 - 2 . With this secondary polishing, the barrier layer is polished. However, there may be a case in which a Cu film and an oxide film left after the primary polishing are also polished.

[0126] A polishing surface of the polishing table 711 - 1 is composed of foamed polyurethane such as IC1000, or a material having abrasive grains fixed thereto or impregnated therein. Upon relative movements of the polishing surface and the semiconductor substrate W, polishing is carried out. At this time, silica, alumina, ceria, on the like is used as abrasive grains or slurry. A chemical liquid is adjusted depending on the type of the film to be polished.

[0127] Detection of an end point of the secondary polishing is performed by measuring the film thickness of the barrier layer mainly with the use of the optical film thickness measuring instrument, and detecting the film thickness which has become zero, or the surface of an insulating film comprising SiO ₂ shows up. Furthermore, a film thickness measuring instrument with an image processing function is used as the film thickness measuring instrument 711 - 4 provided near the polishing table 711 - 1 . By use of this measuring instrument, measurement of the oxide film is made, the results are stored as processing records of the semiconductor substrate W, and used for judging whether the semiconductor substrate W in which secondary polishing has been finished can be transferred to a subsequent step or not. If the end point of the secondary polishing is not reached, re-polishing is performed. If over-polishing has been performed beyond a prescribed value due to any abnormality, then the semiconductor substrate processing apparatus is stopped to avoid next polishing so that defective products will not increase.

[0128] After completion of the secondary polishing, the semiconductor substrate W is moved to the pusher 711 - 5 by the top ring 711 - 2 . The second robot 708 picks up the semiconductor substrate W on the pusher 711 - 5 . At this time, a chemical liquid may be ejected toward the face and backside of the semiconductor substrate W on the pusher 711 - 5 to remove particles therefrom or cause particles to be difficult to adhere thereto.

[0129] The second robot 708 carries the semiconductor substrate W into the second cleaning machine 707 where cleaning of the semiconductor substrate W is performed. The constitution of the second cleaning machine 707 is also the same as the constitution of the first cleaning machine 709 . The face of the semiconductor substrate W is scrubbed with the PVA sponge rolls using a cleaning liquid comprising pure water to which a surface active agent, a chelating agent, or a pH regulating agent is added. A strong chemical liquid such as DHF is ejected from a nozzle toward the backside of the semiconductor substrate W to perform etching of the diffused Cu thereon. If there is no problem of diffusion, scrubbing cleaning is performed with the PVA sponge rolls using the same chemical liquid as that used for the face.

[0130] After completion of the above cleaning, the second robot 708 picks up the semiconductor substrate W and transfers it to the reversing machine 706 , and the reversing machine 706 reverses the semiconductor substrate W. The semiconductor substrate W which has been reversed is picked up by the first robot 703 , and transferred to the third cleaning machine 704 . In the third cleaning machine 704 , megasonic water excited by ultrasonic vibrations is ejected toward the face of the semiconductor substrate W to clean the semiconductor substrate W. At this time, the face of the semiconductor substrate W may be cleaned with a known pencil type sponge using a cleaning liquid comprising pure water to which a surface active agent, a chelating agent, or a pH regulating agent is added. Thereafter, the semiconductor substrate W is dried by spin-drying.

[0131] As described above, if the film thickness has been measured with the film thickness measuring instrument 711 - 4 provided near the polishing table 711 - 1 , then the semiconductor substrate W is not subjected to further process and is accommodated into the cassette placed on the unloading port of the loading/unloading section 771 .

[0132] FIG. 22 is a view showing the plan constitution of another example of a semiconductor substrate processing apparatus. The substrate processing apparatus differs from the substrate processing apparatus shown in FIG. 21 in that a cap plating unit 750 is provided instead of the plated Cu film forming unit 702 in FIG. 21 .

[0133] A cassette 701 - 1 accommodating the semiconductor substrates W formed plated Cu film is placed on a load port of a loading/unloading section 701 . The semiconductor substrate W taken out from the cassette 701 - 1 is transferred to the first polishing apparatus 710 or second polishing apparatus 711 in which the surface of the plated Cu film is polished. After completion of polishing of the plated Cu film, the semiconductor substrate W is cleaned in the first cleaning machine 709 .

[0134] After completion of cleaning in the first cleaning machine 709 , the semiconductor substrate W is transferred to the cap plating unit 750 where cap plating is applied onto the surface of the plated Cu film with the aim of preventing oxidation of plated Cu film due to the atmosphere. The semiconductor substrate to which cap plating has been applied is carried by the second robot 708 from the cap plating unit 750 to the second cleaning unit 707 where it is cleaned with pure water or deionized water. The semiconductor substrate after completion of cleaning is returned into the cassette 701 - 1 placed on the loading/unloading section 701 .

[0135] FIG. 23 is a view showing the plan constitution of still another example of a semiconductor substrate processing apparatus. The substrate processing apparatus differs from the substrate processing apparatus shown in FIG. 22 in that an annealing unit 751 is provided instead of the third cleaning machine 709 in FIG. 22 .

[0136] The semiconductor substrate W, which is polished in the polishing unit 710 or 711 , and cleaned in the first cleaning machine 709 described above, is transferred to the cap plating unit 750 where cap plating is applied onto the surface of the plated Cu film. The semiconductor substrate to which cap plating has been applied is carried by the second robot 732 from the cap plating unit 750 to the first cleaning unit 707 where it is cleaned.

[0137] After completion of cleaning in the first cleaning machine 709 , the semiconductor substrate W is transferred to the annealing unit 751 in which the substrate is annealed, whereby the plated Cu film is alloyed so as to increase the electromigration resistance of the plated Cu film. The semiconductor substrate W to which annealing treatment has been applied is carried from the annealing unit 751 to the second cleaning unit 707 where it is cleaned with pure water or deionized water. The semiconductor substrate W after completion of cleaning is returned into the cassette 701 - 1 placed on the loading/unloading section 701 .

[0138] FIG. 24 is a view showing a plan layout constitution of another example of the substrate processing apparatus. In FIG. 24 , portions denoted by the same reference numerals as those in FIG. 21 show the same or corresponding portions. In the substrate processing apparatus, a pusher indexer 725 is disposed close to a first polishing apparatus 710 and a second polishing apparatus 711 . Substrate placing tables 721 , 722 are disposed close to a third cleaning machine 704 and a plated Cu film forming unit 702 , respectively. A robot 23 is disposed close to a first cleaning machine 709 and the third cleaning machine 704 . Further, a robot 724 is disposed close to a second cleaning machine 707 and the plated Cu film forming unit 702 , and a dry state film thickness measuring instrument 713 is disposed close to a loading/unloading section 701 and a first robot 703 .

[0139] In the substrate processing apparatus of the above constitution, the first robot 703 takes out a semiconductor substrate W from a cassette 701 - 1 placed on the load port of the loading/unloading section 701 . After the film thicknesses of a barrier layer and a seed layer are measured with the dry state film thickness measuring instrument 713 , the first robot 703 places the semiconductor substrate W on the substrate placing table 721 . In the case where the dry state film thickness measuring instrument 713 is provided on the hand of the first robot 703 , the film thicknesses are measured thereon, and the substrate is placed on the substrate placing table 721 . The second robot 723 transfers the semiconductor substrate W on the substrate placing table 721 to the plated Cu film forming unit 702 in which a plated Cu film is formed. After formation of the plated Cu film, the film thickness of the plated Cu film is measured with a before-plating and after-plating film thickness measuring instrument 712 . Then, the second robot 723 transfers the semiconductor substrate W to the pusher indexer 725 and loads it thereon.

[0140] [Serial Mode]

[0141] In the serial mode, a top ring head 710 - 2 holds the semiconductor substrate W on the pusher indexer 725 by suction, transfers it to a polishing table 710 - 1 , and presses the semiconductor substrate W against a polishing surface on the polishing table 710 - 1 to perform polishing. Detection of the end point of polishing is performed by the same method as described above. The semiconductor substrate W after completion of polishing is transferred to the pusher indexer 725 by the top ring head 710 - 2 , and loaded thereon. The second