US20050145482A1

US20050145482A1 - Apparatus and method for processing substrate

Info

Publication number: US20050145482A1
Application number: US10/973,350
Authority: US
Inventors: Hidenao Suzuki; Koji Mishima; Hiroyuki Kanda; Kazufumi Nomura; Kunihito Ide; Kazuyuki Yahiro; Hiroshi Toyoda; Tetsuo Matsuda
Original assignee: Individual
Current assignee: Ebara Corp; Toshiba Corp
Priority date: 2003-10-30
Filing date: 2004-10-27
Publication date: 2005-07-07
Also published as: JP2005133160A

Abstract

An apparatus and a method for processing substrate are generally used for apparatuses for wet-type process of substrate, such as an electrolytic processing apparatus for use in forming interconnects by embedding a metal such as copper (Cu) or the like in fine interconnect patterns (recesses) that are formed in a substrate such as a semiconductor wafer and for use in forming bumps for electrical connections. The substrate processing apparatus includes: a substrate holder for holding a substrate; a first electrode for contacting the substrate to supply electricity to a processing surface of the substrate; a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder; and a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode, wherein the substrate holder is designed to rotate the substrate during processing in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to an apparatus and a method for processing substrate, and more particularly to an apparatus and a method for processing substrate which are generally used for apparatuses for wet-type process of substrate, such as an electrolytic processing apparatus for use in forming interconnects by embedding a metal such as copper (Cu) or the like in fine interconnect patterns (recesses) that are formed in a substrate such as a semiconductor wafer and for use in forming bumps for electrical connections.
2. Description of the Related Art
In recent years, instead of using aluminum or aluminum alloys as a material for forming interconnect circuits on semiconductor substrates, there is an eminent movement towards using copper (Cu) which has a low electric resistivity and high electromigration resistance. Copper interconnects are generally formed by filling copper into fine recesses formed in a surface of a substrate. There are known various techniques for forming such copper interconnects, including CVD, sputtering, and plating. According to any such technique, a copper film is formed on a substantially entire surface of a substrate, followed by removal of unnecessary copper by chemical mechanical polishing (CMP).
FIGS. 11A through 11C illustrate, in sequence of process steps, an example of forming such a substrate W having copper interconnects. As shown in FIG. 11A, an insulating film 2, such as an oxide film of SiO₂or a film of low-k material, is deposited on a conductive layer 1 a on a semiconductor base 1 on which semiconductor devices are formed. Contact holes 3 and interconnect trenches 4 are formed in the insulating film 2 by the lithography/etching technique. Thereafter, a barrier layer 5 of TaN or the like is formed on the surface, and a seed layer 7 as an electric supply layer for electroplating is formed on the barrier layer 5.
Then, as shown in FIG. 11B, copper plating is performed onto the surface of the substrate W 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 5 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 and the surface of the insulating film 2 lie substantially on the same plane. Interconnects composed of the copper film 6, as shown in FIG. 1C, are thus formed.
With conventional electrolytic processing apparatuses, in particular, electroplating apparatuses, there is involved the problem that when carrying out plating of a substrate by bringing a plating solution into contact with a surface (processing surface) of the substrate, microbubbles, particles, etc., which may be present in a small amount in the plating solution, can adhere to the substrate surface. The presence of microbubbles, particles, etc., which remain adhering to the substrate surface during the progress of plating, can cause defects in the device, resulting in a decreased yield.
Electroplating is generally carried out while rotating a substrate in a constant direction. The microbubbles, particles, etc. adhering to the surface of the substrate, however, cannot be released easily from the substrate surface only by such rotation of the substrate, that is, they are likely to remain unremoved on the substrate surface. Thus, such a rotational operational cannot sufficiently reduce defects caused by the presence of microbubbles, particles, etc. on the substrate.
This situation is almost the same with substrate processing apparatuses for carrying out other wet processings, such as a cleaning apparatus for supplying a cleaning liquid onto a surface of a substrate to clean the surface, and a spin coater for coating a resist or the like onto a surface of a substrate while rotating the substrate so as to spread the resist or the like over the entire surface of the substrate, and the like.

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 an apparatus and a method for processing a substrate which can prevent the formation of defects caused by microbubbles, particles, etc. present in a small amount in a processing liquid such as a plating solution, thereby increasing the yield.
In order to achieve the above object, the present invention provides a substrate processing apparatus comprising: a substrate holder for holding a substrate; a first electrode for contacting the substrate to supply electricity to a processing surface of the substrate; a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder; and a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode; wherein the substrate holder is adapted to rotate the substrate during processing in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.
According to this apparatus, a substrate is rotated during electrolytic processing, such as plating, in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated so as to stir a processing liquid, such as a plating solution, around the substrate surface. Accordingly, if microbubbles, particles, etc. present in a small amount in the processing liquid adhere to the substrate, they are forced to leave the substrate. The processing, such as plating, can thus be progressed in the absence of microbubbles, particles, etc. on the substrate.
The present invention provides another substrate processing apparatus comprising; a substrate holder for holding a substrate; a first electrode for contacting the substrate to supply electricity to a processing surface of the substrate; a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder; a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode; and a vibrating mechanism for vibrating the substrate held by the substrate holder.
According to this apparatus, a processing liquid, such as a plating solution, around a surface of a substrate can be stirred during electrolytic processing, such as plating, by vibrating the substrate held by the substrate holder. Thus, this apparatus likewise can promote the release of microbubbles, particles, etc. from the substrate.
The vibrating mechanism is comprised of, for example, a vibration exciter for vibrating the substrate holder, an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, through its contact with the back surface of the substrate, or an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, in a contactless manner.
The present invention provides yet another substrate processing apparatus comprising: a substrate holder for holding a substrate; a first electrode for contacting the substrate to supply electricity to a processing surface of the substrate; a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder; a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode; and a vibrating mechanism for vibrating the second electrode.
According to this apparatus, a processing liquid, such as a plating solution, around a surface of a substrate can be stirred during electrolytic processing, such as plating, by vibrating the second electrode. Thus, this apparatus likewise can promote the release of microbubbles, particles, etc. from the substrate.
The vibrating mechanism is comprised of, for example, a vibration exciter for vibrating the second electrode in the vertical direction.
Preferably, a high-resistance structure having a higher electric resistance than the processing liquid is disposed between the substrate held by the substrate holder and the second electrode.
The substrate processing apparatus is, for example, an electroplating apparatus in which the first electrode serves as a cathode and the second electrode serves as an anode, and the processing liquid is a plating solution.
The present invention provides yet another substrate processing apparatus comprising: a substrate holder for holding a substrate; and a processing liquid supply section for supplying a processing liquid to a processing surface of the substrate held by the substrate holder; wherein the substrate holder is adapted to rotate the substrate during processing in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.
The processing of the substrate includes cleaning comprising supplying a processing liquid, such as a cleaning liquid or pure water, to the processing surface of the substrate, and spin coating comprising supplying a processing liquid, such as a resist solution, to the processing surface of the substrate.
The present invention provides yet another substrate processing apparatus comprising: a substrate holder for holding a substrate; a processing liquid supply section for supplying a processing liquid to a processing surface of the substrate held by the substrate holder; and a vibrating mechanism for vibrating the substrate held by the substrate holder.
The vibrating mechanism is comprised of, for example, a vibration exciter for vibrating the substrate holder, an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, through its contact with the back surface of the substrate, or an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, in a contactless manner.
The present invention provides a substrate processing method comprising: filling a space between a processing surface of a substrate, to which electricity is supplied from a first electrode, and a second electrode disposed so as to face the processing surface with an electrolytic liquid; and electrolytically processing the processing surface by applying a voltage between the first electrode and the second electrode while rotating the substrate in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.
The present invention provides another substrate processing method comprising: filling a space between a processing surface of a substrate, to which electricity is supplied from a first electrode, and a second electrode disposed so as to face the processing surface with an electrolytic liquid; and electrolytically processing the processing surface by applying a voltage between the first electrode and the second electrode while vibrating at least one of the substrate and the second electrode.
The present invention provides yet another substrate processing method comprising; supplying a processing liquid to a processing surface of a substrate; and processing the processing surface while rotating the substrate in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.
The present invention provides yet another substrate processing method comprising; supplying a processing liquid to a processing surface of a substrate; and processing the processing surface while vibrating the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an electroplating apparatus (substrate processing apparatus) according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram showing an electroplating apparatus (substrate processing apparatus) according to a second embodiment of the present invention;
FIG. 3 is a schematic diagram showing an electroplating apparatus (substrate processing apparatus) according to a third embodiment of the present invention;
FIG. 4 is a schematic diagram showing an electroplating apparatus (substrate processing apparatus) according to a fourth embodiment of the present invention;
FIG. 5 is a schematic diagram showing an electroplating apparatus (substrate processing apparatus) according to a fifth embodiment of the present invention;
FIG. 6 is a cross-sectional diagram showing the main portion of an electroplating apparatus (substrate processing apparatus) according to a sixth embodiment of the present invention;
FIG. 7 is a diagram showing the positional relationship between a substrate, a lip seal and a plating solution supply section in the electroplating apparatus shown in FIG. 6 upon plating;
FIG. 8 is a cross-sectional diagram showing the main portion of an electroplating apparatus (substrate processing apparatus) according to a seventh embodiment of the present invention;
FIG. 9 is a diagram showing the positional relationship between a substrate, a lip seal and a plating solution supply section in the electroplating apparatus shown in FIG. 8 upon plating;
FIG. 10 is a graph showing the results of measurement of the number of defects formed in the plated film of a substrate in cases where plating is carried out while rotating the substrate at a constant speed in one direction (reference), where plating is carried out while vibrating the substrate with a vibration exciter (vibration exciter), and where plating is carried out while repeating acceleration and slowdown of the rotational speed of the substrate (acceleration and slowdown); and
FIGS. 11A through 11C are diagrams illustrating, in a sequence of process steps, an example of forming copper interconnects by plating.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the drawings. The following description illustrates application of the present invention to electroplating apparatuses using a plating solution as a processing liquid, and utilizing the first electrode as a cathode and the second electrode as an anode. It is, of course, possible to apply the present invention to electrolytic etching apparatuses by using an electrolytic etching liquid as a processing liquid, and utilizing the first electrode as an anode and the second electrode as a cathode.
FIG. 1 shows an electroplating apparatus (substrate processing apparatus) according to a first embodiment of the present invention. As shown in FIG. 1, the electroplating apparatus includes a substrate holder 14, coupled to an upper end of a main shaft 12, which is rotatable and vertically movable by a drive section 10, for detachably holding a substrate W with its front surface facing upwardly (face up), and a vertically movable electrode head 16 disposed above the substrate holder 14.
A ring-shaped lip seal 18 formed of an elastic material and a leaf spring-like cathode (first electrode) 20 surrounding the lip seal 18 are concentrically disposed above the substrate holder 14 such that they cover the peripheral region of the substrate holder 14. When the substrate holder 14 holding a substrate W is raised, the lip seal 18 comes into contact with a peripheral portion of the substrate W. By further raising the substrate holder 14, the lip seal 18 is brought into pressure contact with the peripheral portion of the substrate W, thereby watertightly sealing the peripheral portion. A plating cell 22 is thus formed by the upper surface of the substrate W and the lip seal 18. At the same time, the cathode 20 is pressed against a peripheral portion of the substrate W to supply electricity thereto, so that a seed layer 7 (see FIG. 11) formed in the surface of the substrate W is connected to the cathode of a power source 24 and becomes a cathode.
Since the cathode 20 is disposed outside the lip seal 18, the cathode 20 can be prevented from being contaminated with a plating solution 26 introduced into the plating cell 22.
The substrate holder 14 includes a disc-shaped substrate stage 28 for placing and holding the substrate W on the upper surface, and a plurality of openable and closable clamps 30 for clamping a peripheral portion of the substrate W placed on the substrate stage 28.
The electrode head 16 is supported at the free end of a pivot arm 34 that is fixed to the upper end of a vertically movable lifting shaft 32. The electrode head 16 includes a downwardly-open cylindrical housing 36 and a high-resistance structure 38 disposed such that it closes the bottom opening of the housing 36. The housing 36 has, at a lower portion thereof, a recessed portion 36 a extending in the circumferential direction, while the high-resistance structure 38 has at its top a flange portion 38 a. The high-resistance structure 38 is held in the housing 36 by insertion of the flange portion 38 a into the recessed portion 36 a. A plating solution chamber 40 is thus formed over the high-resistance structure 38 in the housing 36.
The high-resistance structure 38 is composed of, for example, a porous ceramic, such as alumina, SiC, mullite, zirconia, titania or cordierite, or a hard porous body, such as a sintered body of polypropylene or polyethylene, or a compound thereof, or a woven or non-woven fabric. For example, a porous ceramic plate may be used having a pore diameter of 30 to 200 μm in the case of an alumina ceramic, or not more than 30 μm in the case of SiC, a porosity of 20 to 95%, and a thickness of 1 to 20 mm, preferably 5 to 20 mm, more preferably 8 to 15 mm. According to this embodiment, the high-resistance structure 38 is composed of a porous alumina ceramic plate, for example, having a porosity of 30% and an average pore diameter of 100 μm. Though the high-resistance structure 38, composed of such a porous ceramic plate, itself is an insulating material, it has an electric conductivity when it contains a plating solution. In particular, a plating solution can penetrate deep into the porous ceramic plate in the thickness direction though complicated, fairly long paths of the pores. This can provide the high-resistance structure 38 containing the plating solution with an electric conductivity which is lower than the electric conductivity of the plating solution.
The provision of the high-resistance structure 38, which can thus have a high electric resistance in the housing 36, can make the influence of the resistance of the seed layer 7 and copper film 6 (see FIG. 11B) as small as negligible. Thus, a variation of current density in the entire surface of the substrate W due to the electric resistance can be made small, thereby improving the uniformity of a plated film over the entire surface of the substrate.
An anode (second electrode) 42 to be connected to the anode of the power source 24 is disposed over the high-resistance structure 38 in the housing 36. A plating solution supply pipe 44 as a plating solution supply section is mounted to the upper surface of the anode 42. The plating solution supply pipe 44 has a manifold structure so that a plating solution can be supplied uniformly to the high-resistance structure 38. Thus, a number of narrow tubes 46, which are in fluid communication with the plating solution supply pipe 44, are coupled to the pipe 44 at predetermined positions along the long direction of the pipe 44. The high-resistance structure 38 and the anode 42 have narrow holes at positions corresponding to the narrow tubes 46, and the narrow tubes 46 extend downwardly in the narrow holes. Further, the anode 42 has a large number of through-holes 42 a vertically penetrating the anode 42.
Though not shown diagrammatically, the housing 36 is provided with a plating solution suction pipe for sucking in the plating solution in the plating solution chamber 40 within the housing 36.
The plating solution, introduced into the plating solution supply pipe 44, passes through the narrow tubes 46 and is supplied into the plating cell 22 defined by the substrate W, held by the substrate holder 14, and the lip seal 18. On the other hand, the plating solution 26 has been held within the high-resistance structure 38, and the plating solution has been stored at a certain surface level in the plating solution chamber 40. The space between the anode 42 and the substrate W held by the substrate holder 14 is thus filled with the plating solution 26.
In order to suppress generation of slime, the anode 42 is made of copper containing 0.03 to 0.05% of phosphorus (phosphorus-containing copper). However, an insoluble electrode may also be employed.
According to this embodiment, a band-shaped insulating member 48 is wrapped around the circumferential surface of the high-resistance structure 38 to prevent an electric current from flowing out of the circumferential surface of the high-resistance structure 38. An elastic material, such as a fluorine-contained rubber, may be used for the insulating member 48.
The operation of the electroplating apparatus of this embodiment in carrying out plating will now be described. The following description illustrates the case of providing a substrate W, as shown in FIG. 11A, having a seed layer 7, serving as an electric supply layer in electroplating, formed in the front surface (processing surface), and carrying out copper electroplating of the surface of the substrate W to embed copper into contact holes 3 and interconnect trenches 4 as fine interconnect recesses.
First, the substrate W having the seed layer 7 is held with the front surface (processing surface) facing upwardly by the substrate holder 14, and the substrate holder 14 is raised to bring a peripheral portion of the substrate W into pressure contact with the lip seal 18, thereby forming the plating cell 22 defined by the upper surface of the substrate W and the lip seal 18. At the same time, the cathode 20 is brought into contact with the seed layer 7. The electrode head 16, on the other hand, is in an idling position. The plating solution is supplied into the plating solution chamber 40 in the housing 36, and the plating solution is held within the high-resistance structure 38.
Next, the electrode head 16 is moved from the idling position to a position right above the substrate holder 14 and is then lowered. The lowering is stopped when the lower surface of the high-resistance structure 38 has reached a position close to the front surface of the substrate W held by the substrate holder 14, the position being at a distance of about 0.5 mm to 3 mm from the surface of the substrate W. Thereafter, the plating solution 26 is supplied through the plating solution supply pipe 44 into the plating cell 22 defined by the substrate W and the lip seal 18, thereby filling the space between the surface of the substrate W and the cathode 20 with the plating solution 26. A plating voltage is applied from the power source 24 to between the anode 42 and the seed layer 7 as a cathode to carry out plating of the surface of the seed layer 7.
During the plating, the substrate W held by the substrate holder 14 is rotated in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated. For example, a step of rotating the substrate W at an acceleration A for a time a until the rotational speed reaches X, and a step of rotating the substrate W at an acceleration B for a time β until the rotational speed reaches Y are repeated, as shown in Table 1 below. The accelerations A, B may either be positive accelerations, negative accelerations or a combination of a positive acceleration and a negative acceleration. The both rotations of the substrate W for the rotational speeds X, Y may be normal rotations or reverse rotations.

TABLE 1

Step 1 2 3 4 5 6 Repeated

Rotational speed X Y X Y X Y →

(min⁻¹)

Acceleration A B A B A B

Time (sec) α β α β α β →
According to this embodiment, the substrate W is thus rotated during electrolytic processing, such as plating, in such a manner that acceleration and showdown and/or normal rotation and reverse rotation are repeated so as to stir the plating solution 26 around the surface of the substrate W. Accordingly, if microbubbles, particles, etc. present in a small amount in the plating solution 26 adhere to the substrate W, they are forced to leave the substrate W. Plating can thus be progressed in the absence of microbubbles, particles, etc. on the substrate W.
When the copper film 6 (see FIG. 11B) formed on the surface of the seed layer 7 has reached a predetermined thickness, the application of plating voltage is stopped to terminate plating. The electrode head 16 is then raised, and the plating solution 26 remaining on the surface of the substrate W is removed by suction. Thereafter, the substrate holder 14 is lowered, and the substrate W after plating, held by the substrate holder 14, is transferred to the next process step.
FIG. 2 shows an electroplating apparatus (substrate processing apparatus) according to a second embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 1 in that the rotatable and vertically movable main shaft 12 is divided into upper and lower shafts, and a vibration exciter 50 for vibrating the upper main shaft 12 a vertically and/or horizontally is mounted between the two shafts. The vibration exciter 50 is actuated during plating to vibrate a substrate W, held by the substrate holder 14, vertically and/or horizontally.
The plating solution 26 around the surface of the substrate W can be stirred also by thus vibrating the substrate W, held by the substrate holder 14, vertically and/or horizontally by the vibration exciter 50, enabling the progress of plating in the absence of microbubbles, particles, etc. on the substrate W, as described above.
FIG. 3 shows an electroplating apparatus (substrate processing apparatus) according to a third embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 1 in that an ultrasonic transducer 52, which transmits ultrasonic waves to a substrate W, held by the substrate holder 14, through its contact with the back surface of the substrate W, is mounted to the substrate holder 14. The ultrasonic transducer 52 is actuated during plating to vibrate the substrate W held by the substrate holder 14.
The plating solution 26 around the surface of the substrate W can be stirred also by thus vibrating the substrate W, held by the substrate holder 14, by the ultrasonic transducer 52, enabling the progress of plating in the absence of microbubbles, particles, etc. on the substrate W, as described above.
FIG. 4 shows an electroplating apparatus (substrate processing apparatus) according to a fourth embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 3 in that an ultrasonic transducer 56, for example, a speaker, which transmits ultrasonic waves to a substrate W, held by the substrate holder 14, in a contactless manner, is mounted to an apparatus frame 54 housing the plating apparatus. The ultrasonic transducer 56 is actuated during plating to vibrate the substrate W, held by the substrate holder 14, in a contactless manner.
FIG. 5 shows an electroplating apparatus (substrate processing apparatus) according to a fifth embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 1 in that a vibration exciter 58 for vibrating the electrode head 16 vertically and/or horizontally is interposed between the pivot arm 34 and the electrode head 16. The vibration exciter 58 is actuated during plating to vibrate the anode 42 vertically and/or horizontally.
The vibration of the anode 42 is transmitted to the plating solution 26 directly or indirectly. The plating solution 26 around the surface of the substrate W can therefore be stirred also by thus vibrating the anode 42 vertically and/or horizontally by the vibration exciter 58, enabling the progress of plating in the absence of microbubbles, particles, etc. on the substrate W, as described above.
FIGS. 6 and 7 show an electroplating apparatus (substrate processing apparatus) according to a sixth embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 1 in that instead of the plating solution supply pipe 44 of FIG. 1, a plating solution supply section 104, positioned beside the anode 42 and the high-resistance structure 38, and vertically penetrating the peripheral wall of the housing 36, is provided within the peripheral wall of the housing 36. According to this embodiment, the plating solution supply section 104 is comprised of a tube with a nozzle-shaped lower end. In FIG. 6 is shown a plating solution discharge outlet 103, connected to the housing 36, for sucking in and discharging the plating solution 26 in the plating solution chamber 40.
The plating solution supply section 104 is to supply the plating solution 26 from the side of the anode 42 and the high-resistance structure 38 into the space between the substrate W and the high-resistance structure 38, and the lower-end nozzle portion opens to the space between the lip seal 18 and the high-resistance structure 38.
The plating solution 26, supplied from the plating solution supply section 104 at the time of supply of the plating solution, flows in one direction over the front surface of the substrate W, as shown in FIG. 7, and by the flow of plating solution, air in the space between the substrate W and the high-resistance structure 38 is forced out of the space. The space is thus filled with the fresh, composition-adjusted plating solution injected from the plating solution supply section 104, and the plating solution is stored in the plating cell 22 defined by the substrate W and the lip seal 18.
By thus injecting the plating solution from the side of the anode 42 and the high-resistance structure 38 into the space between the substrate W and the high-resistance structure 38, the filling of plating solution can be carried out without provision of, for example, a plating solution supply tube composed of an insulating material, which may disturb the electric field distribution, within the high-resistance structure 38. This can make the electric field distribution uniform over the entire surface of the substrate even it the substrate has a large area. Furthermore, the plating solution, which has been held in the high-resistance structure 38, can be prevented from leaking out of the high-resistance structure 38 upon the injection of a fresh plating solution. Accordingly, the fresh, composition-adjusted plating solution can be supplied into the space between the substrate W held by the substrate holder 14 (see e.g. FIG. 1) and the high-resistance structure 38.
FIGS. 8 and 9 show an electroplating apparatus (substrate processing apparatus) according to a seventh embodiment of the present invention. This embodiment differs from the embodiment shown in FIGS. 6 and 7 in that a plating solution suction section 130 for sucking in the plating solution injected between the substrate W and the high-resistance structure 38 is provided beside the anode 42 and the high-resistance structure 38, and on the opposite side of the high-resistance structure 38 from the plating solution supply section 104 in the housing 36. Though not shown diagrammatically, the plating solution 26, supplied into the space between the substrate W and the high-resistance structure 38 and stored in the plating cell 22 defined by the substrate W and the lip seal 18, is returned from the plating solution suction section 130 to a plating solution tank (not shown) in a circulatory manner.
According to this embodiment, the electrode head 16 is lowered until the distance between the substrate W and the high-resistance structure 38 becomes, for example, about 0.5 to 3 mm, and the plating solution is injected from the plating solution supply section 104 into the space between the substrate W and the high-resistance structure 38. The plating solution 26 injected fills the space and is stored in the plating cell 22 defined by the substrate W and the lip seal 18 while the plating solution 26 is sucked in by the plating solution suction section 130. Plating of the surface of the substrate W is thus carried out while keeping the space between the substrate W and the high-resistance structure 38 filled with the plating solution flowing in one direction, as shown in FIG. 9.
According to this embodiment, the plating solution 26 is thus injected from the side of the high-resistance structure 38 into the space between the substrate w and the high-resistance structure 38, and the plating solution 26 is allowed to circulate so that the plating solution 26 constantly flows between the substrate W and the high-resistance structure 38. This can prevent the formation of plating defects, i.e. non-plated portions, caused by a stop of the flow of plating solution during electroplating. Further, rotating the substrate according to necessity enables the plating solution to flow at an even speed over the central and peripheral portions of the substrate W.
FIG. 10 shows the results of measurement of the number of defects formed in the plated film of a substrate (No. 3) (vibration exciter), the plated film being obtained by plating of the surface of the substrate carried out by keeping the substrate, held by a substrate holder, and a high-resistance structure close to each other and vibrating the substrate with a vibration exciter during plating. FIG. 10 also shows the results of measurement of the number of defects formed in the plated films of two substrates (No. 4, No. 5) (acceleration and slowdown), the plated films each being obtained by plating of the surface of the substrate carried out by keeping the substrate, held by the substrate holder, and the high-resistance structure close to each other and repeating acceleration and slowdown of the rotational speed of the substrate during plating. For comparison, FIG. 10 also shows the results of measurement of the number of defects formed in the plated films of two substrates (No. 1, No. 2) (reference), the plated films each being obtained by plating of the surface of the substrate carried out by keeping the substrate, held by the substrate holder, and the high-resistance structure close to each other and rotating the substrate at a constant speed in one direction.
The data in FIG. 10 demonstrates the fact that the number of defects formed in the plated film of a substrate can be decreased by carrying out plating of the substrate while vibrating the substrate by a vibration exciter, or while repeating acceleration and slowdown of the rotational speed of the substrate.
Though the above-described embodiments relate to application of the present invention to electroplating apparatuses using a plating solution as a processing liquid, and utilizing the first electrode as a cathode and the second electrode as an anode, the present invention, of course, is applicable to electrolytic etching apparatuses by using an electrolytic etching liquid as a processing liquid, and utilizing the first electrode as an anode and the second electrode as a cathode.
Further, though the above embodiments relate to electrolytic processing apparatuses provided with the first electrode and the second electrode, the present invention is also applicable to substrate processing apparatuses for performing wet processing, such as an electroless plating apparatus, a cleaning apparatus and a spin coater, by omitting the first electrode and the second electrode or by not applying a voltage between the first electrode and the second electrode.
According to the present invention, a processing liquid, such as a plating solution, around a substrate surface is stirred during electrolytic processing, such as plating, thereby promoting release of microbubbles, particles, etc. adhering to the substrate surface. This can prevent the microbubbles, particles, etc. from remaining on the substrate surface during the progress of plating, thereby increasing the yield. This holds for other wet processings than plating, such as cleaning and spin coating.

Claims

1. A substrate processing apparatus comprising:

a substrate holder for holding a substrate;

a first electrode for contacting the substrate to supply electricity to a processing surface of the substrate;

a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder; and

a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode;

wherein the substrate holder is adapted to rotate the substrate during processing in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.

2. The substrate processing apparatus according to claim 1, wherein a high-resistance structure having a higher electric resistance than the processing liquid is disposed between the substrate held by the substrate holder and the second electrode.

3. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is an electroplating apparatus in which the first electrode serves as a cathode and the second electrode serves as an anode, and the processing liquid is a plating solution.

4. A substrate processing apparatus comprising:

a substrate holder for holding a substrate;

a second electrode disposed so as to face the processing surface of the substrate held by the substrate holder;

a processing liquid supply section for supplying a processing liquid into the space between the processing surface of the substrate held by the substrate holder and the second electrode; and

a vibrating mechanism for vibrating the substrate held by the substrate holder.

5. The substrate processing apparatus according to claim 4, wherein the vibrating mechanism is comprised of a vibration exciter for vibrating the substrate holder.

6. The substrate processing apparatus according to claim 4, wherein the vibrating mechanism is comprised of an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, through its contact with the back surface of the substrate.

7. The substrate processing apparatus according to claim 4, wherein the vibrating mechanism is comprised of an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, in a contactless manner.

8. The substrate processing apparatus according to claim 4, wherein a high-resistance structure having a higher electric resistance than the processing liquid is disposed between the substrate held by the substrate holder and the second electrode.

9. The substrate processing apparatus according to claim 4, wherein the substrate processing apparatus is an electroplating apparatus in which the first electrode serves as a cathode and the second electrode serves as an anode, and the processing liquid is a plating solution.

10. A substrate processing apparatus comprising:

a substrate holder for holding a substrate;

a vibrating mechanism for vibrating the second electrode.

11. The substrate processing apparatus according to claim 10, wherein the vibrating mechanism is comprised of a vibration exciter for vibrating the second electrode in the vertical direction.

12. The substrate processing apparatus according to claim 10, wherein a high-resistance structure having a higher electric resistance than the processing liquid is disposed between the substrate held by the substrate holder and the second electrode.

13. The substrate processing apparatus according to claim 10, wherein the substrate processing apparatus is an electroplating apparatus in which the first electrode serves as a cathode and the second electrode serves as an anode, and the processing liquid is a plating solution.

14. A substrate processing apparatus comprising:

a substrate holder for holding a substrate; and

a processing liquid supply section for supplying a processing liquid to a processing surface of the substrate held by the substrate holder;

15. A substrate processing apparatus comprising:

a substrate holder for holding a substrate;

a processing liquid supply section for supplying a processing liquid to a processing surface of the substrate held by the substrate holder; and

a vibrating mechanism for vibrating the substrate held by the substrate holder.

16. The substrate processing apparatus according to claim 15, wherein the vibrating mechanism is comprised of a vibration exciter for vibrating the substrate holder.

17. The substrate processing apparatus according to claim 15, wherein the vibrating mechanism is comprised of an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, through its contact with the back surface of the substrate.

18. The substrate processing apparatus according to claim 15, wherein the vibrating mechanism is comprised of an ultrasonic transducer which transmits ultrasonic waves to the substrate, held by the substrate holder, in a contactless manner.

19. A substrate processing method comprising:

filling a space between a processing surface of a substrate, to which electricity is supplied from a first electrode, and a second electrode disposed so as to face the processing surface with an electrolytic liquid; and

electrolytically processing the processing surface by applying a voltage between the first electrode and the second electrode while rotating the substrate in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.

20. A substrate processing method comprising:

electrolytically processing the processing surface by applying a voltage between the first electrode and the second electrode while vibrating at least one of the substrate and the second electrode.

21. A substrate processing method comprising;

supplying a processing liquid to a processing surface of a substrate; and

processing the processing surface while rotating the substrate in such a manner that acceleration and slowdown and/or normal rotation and reverse rotation are repeated.

22. A substrate processing method comprising;

supplying a processing liquid to a processing surface of a substrate; and

processing the processing surface while vibrating the substrate.