U.S. patent application number 10/484452 was filed with the patent office on 2004-10-21 for electrolytic processing apparatus and substrate processing apparatus and method.
Invention is credited to Kobata, Itsuki, Kumekawa, Masayuki, Noji, Ikutaro, Shirakashi, Mitsuhiko, Yasuda, Hozumi, Yoshida, Kaori.
Application Number | 20040206634 10/484452 |
Document ID | / |
Family ID | 27670281 |
Filed Date | 2004-10-21 |
United States Patent
Application |
20040206634 |
Kind Code |
A1 |
Shirakashi, Mitsuhiko ; et
al. |
October 21, 2004 |
Electrolytic processing apparatus and substrate processing
apparatus and method
Abstract
The present invention alleviates workloads in
chemical-mechanical polishing (CMP) by replacing all or a portion
of the substrate processing by means of chemical-mechanical
polishing with electrolytic processing using deionized water,
ultrapure water or the like and enables processing insuring the
higher flatness with the higher efficiency. The electrolytic
processing apparatus according to the present invention comprises a
chemical-mechanical polishing section 24 for
chemically-mechanically polishing a surface of a substrate of a
substrate, an electrolytic processing section 26 having a
processing electrode and a feeding electrode and also having an ion
exchanger 48 provided at least either between the substrate and the
processing electrode or between the substrate and the feeding
electrode for electrolytically processing a surface of a workpiece
under the existence of a solution by applying a voltage between the
processing electrode and the feeding electrode; and a top ring 74
capable of freely moving between the chemical-mechanical polishing
section 24 and the processing electrode section 26.
Inventors: |
Shirakashi, Mitsuhiko;
(Tokyo, JP) ; Kumekawa, Masayuki; (San Jose,
CA) ; Yasuda, Hozumi; (Tokyo, JP) ; Kobata,
Itsuki; (Tokyo, JP) ; Noji, Ikutaro; (Tokyo,
JP) ; Yoshida, Kaori; (Tokyo, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
27670281 |
Appl. No.: |
10/484452 |
Filed: |
June 10, 2004 |
PCT Filed: |
January 31, 2003 |
PCT NO: |
PCT/JP03/01024 |
Current U.S.
Class: |
205/641 ;
205/645; 257/E21.303; 257/E21.304 |
Current CPC
Class: |
B24B 37/04 20130101;
C25F 5/00 20130101; H01L 21/3212 20130101; B23H 3/08 20130101; H01L
21/32115 20130101; B23H 3/00 20130101; B23H 3/04 20130101; C25F
7/00 20130101; B23H 5/08 20130101; C25F 3/00 20130101 |
Class at
Publication: |
205/641 ;
205/645 |
International
Class: |
B23H 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2002 |
JP |
2002-023785 |
Mar 29, 2002 |
JP |
2002-096230 |
Nov 13, 2002 |
JP |
2002-330039 |
Claims
1. An electrolytic processing apparatus comprising: an electrolytic
processing section having a processing electrode and a feeding
electrode, for electrolytically processing a surface of a workpiece
in the presence of a liquid by applying a voltage between the
processing electrode and the feeding electrode; and a processing
end point detecting section for detecting a processing end point by
detecting a change in a frictional force generated between the
workpiece and at least one of the processing electrode and the
feeding electrode during the processing.
2. An electrolytic processing apparatus comprising: an electrolytic
processing section having a processing electrode and a feeding
electrode, for electrolytically processing a surface of a workpiece
in the presence of a liquid by applying a voltage between the
processing electrode and the feeding electrode; and a processing
end point detecting section for detecting a processing end point by
detecting a change in an amount of heat generated between the
workpiece and at least one of the processing electrode and the
feeding electrode during the processing.
3. An electrolytic processing apparatus comprising: an electrolytic
processing section having a processing electrode and a feeding
electrode, for electrolytically processing a surface of a workpiece
in the presence of a liquid by applying a voltage between the
processing electrode and the feeding electrode; and a processing
end point detecting section for detecting a processing end point by
detecting a change in amplitude of a light reflected from a
processed surface of the workpiece.
4. An electrolytic processing apparatus comprising: an electrolytic
processing section having a processing electrode and a feeding
electrode, for electrolytically processing a surface of a workpiece
in the presence of a liquid by applying a voltage between the
processing electrode and the feeding electrode; and a processing
end point detecting section for detecting a processing end point by
detecting a change in an eddy current generated inside the
workpiece during the processing.
5. An electrolytic processing apparatus comprising: an electrolytic
processing section having a processing electrode and a feeding
electrode, for electrolytically processing a surface of a workpiece
in the presence of a liquid by applying a voltage between the
processing electrode and the feeding electrode; and a processing
end point detecting section for detecting a processing end point by
detecting and integrating a current flowing between the processing
electrode and the feeding electrode during the processing.
6. A substrate processing apparatus comprising: a
chemical-mechanical polishing section for chemically and
mechanically polishing a surface of a substrate; an electrolytic
processing section having a processing electrode, a feeding
electrode and an ion exchanger disposed at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode, and for electrolytically processing a
surface of the substrate in the presence of a liquid by applying a
voltage between the feeding electrode and the processing electrode;
and a top ring releasably holding the substrate and movable between
the chemical-mechanical polishing section and the electrolytic
processing section.
7. A substrate processing apparatus comprising: a
chemical-mechanical polishing section for chemically and
mechanically polishing a surface of a substrate; an electrolytic
processing section having a feeding electrode and a processing
electrode, for electrolytically processing the surface of the
substrate in the presence of deionized water or a liquid with an
electric conductivity of 500 .mu.S/cm or below between the
substrate and each or at least one of the processing electrode, and
the feeding electrode, and applying a voltage between the feeding
electrode and the processing electrode; and a top ring releasably
holding a substrate and freely movable between the
chemical-mechanical polishing section and the electrolytic
processing section.
8. A substrate processing apparatus comprising: a
chemical-mechanical polishing section for chemically and
mechanically polishing a surface of a substrate; an electrolytic
processing section having a processing electrode, a feeding
electrode and an ion exchanger disposed at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode, for electrolytically processing the surface
of the substrate in the presence of a liquid by applying a voltage
between the feeding electrode and the processing electrode; one or
more top rings for releasably holding the substrate; and a pusher
located between said chemical-mechanical polishing section and said
electrolytic processing section and transferring the substrate
between the chemical-mechanical polishing section and the
electrolytic processing section.
9. A substrate processing apparatus comprising: a
chemical-mechanical polishing section for chemically and
mechanically polishing a surface of a substrate; an electrolytic
processing section having the feeding electrode and a processing
electrode, for electrolytically processing the surface of the
substrate in the presence of deionized water or a liquid with an
electric conductivity of 500 .mu.S/cm or below to at least either
between the substrate and the processing electrode or between the
substrate and the feeding electrode; one or more top rings for
releasably holding the substrate; and a pusher located between said
chemical-mechanical polishing section and said electrolytic
processing section and for transferring the substrate between the
chemical-mechanical polishing section and the electrolytic
processing section.
10. The substrate processing apparatus according to claim 6,
wherein said chemical-mechanical polishing section performs a
chemical-mechanical polishing using fixed abrasive member.
11. The substrate processing apparatus according to claim 6,
wherein an anti-oxidant is added in the liquid used in the
electrolytic processing section.
12. The substrate processing apparatus according to claim 6,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
13. A method for processing a substrate using three or more process
stages comprising: polishing a surface of the substrate by
chemical-mechanical polishing; and removing unnecessary portions
from the surface of the substrate by electrolytic processing using
deionized water or ultrapure water or liquid with an electric
conductivity of 500 .mu.S/cm or below.
14. A method for processing a substrate using three or more process
stages comprising: polishing a surface of the substrate by
chemical-mechanical polishing; and removing unnecessary portions of
the substrate by electrolytic processing placing an ion exchanger
at least either between the substrate and an processing electrode
or between the substrate and the feeding electrode and applying a
voltage between the feeding electrode and the processing electrode
in the presence of deionized water, a liquid with an electric
conductivity of 500 uS/cm or below, or an electrolytic
solution.
15. A method for processing substrate comprising: polishing a
surface of the substrate by chemical-mechanical polishing using a
fixed abrasive member; and removing unnecessary portions of the
substrate with deionized water or ultrapure water or liquid with an
electric conductivity of 500 .mu.S/cm or below.
16. A substrate processing apparatus comprising: a plurality of
electrolytic processing sections, each of said electrolytic
processing sections having a feeding electrode and a processing
electrode, for electromechanically processing a surface of a
substrate by supplying a fluid to at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode and supplying a voltage to between the
feeding electrode and the processing electrode.
17. The substrate processing apparatus according to claim 16,
wherein an ion exchanger is provided at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode in at least one of the plurality of
electrolytic processing sections.
18. The substrate processing apparatus according to claim 16,
wherein an ion exchanger is provided at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode in all of the plurality of electrolytic
processing sections.
19. The substrate processing apparatus according to claim 17 or 18
comprising a plurality of electrolytic processing sections with
different types of ion exchangers respectively.
20. The substrate processing apparatus according to any one of
claims 16 to 19 claim 16 further comprising a chemical-mechanical
polishing section for chemically and mechanically polishing a
surface of a substrate.
21. A substrate processing apparatus comprising: an ion exchanger
holding member for holding an ion exchanger; an electrolytic
processing section having a processing electrode, a feeding
electrode and an ion exchanger disposed at least either between the
substrate and the processing electrode or between the substrate and
the feeding electrode, for electrolytically processing a surface of
the substrate in the presence of a liquid by applying a voltage
between the feeding electrode and the processing electrode; and an
ion exchanger replacement means for replacing the ion exchanger
holding member in the electrolytic processing section with another
ion exchanger holding member.
22. The substrate processing apparatus according to claim 21,
wherein said electrolytic processing section has a plurality of ion
exchanger holding members.
23. A substrate processing method for electrolytically processing a
surface of a substrate through a multi-stage process in the
presence of a liquid, an ion exchanger at least between a substrate
and the processing electrode or between the substrate and the
feeding electrode, and a voltage applied between the processing
electrode and the feeding electrode, the method comprising:
electrolytically processing the substrate using a first ion
exchanger; and electrolytically processing the substrate using a
second ion exchanger, wherein said first ion exchanger has high
elasticity than that of said second ion exchanger.
24. A substrate processing method for removing unnecessary portions
of a surface of a substrate by using a plurality of steps of:
carrying out electrolytic processing by placing an ion exchanger at
least between the substrate and the processing electrode or between
the substrate and the feeding electrode, applying a voltage between
the processing electrode and the feeding electrode, and causing a
relative movement between the substrate and at least one of the
processing electrode and the feeding electrode in the presence of a
ultrapure water, deionized water or a fluid with an electric
conductivity of 500 .mu.S/cm or below; carrying out electrolytic
processing by applying a voltage between the processing electrode
and the feeding electrode and also causing a relative movement
between the substrate and at least one of the processing electrode
and the feeding electrode in the presence of an electrolytic
solution; and carrying out polishing by chemical-mechanical
polishing.
25. The substrate processing method as descrimember in claim 24
further comprising: removing conductive materials on the surface of
the substrate by electrolytic processing using an ion exchanger;
and removing a barrier layer on the surface of the substrate by
either electrolytic processing with an electrolytic solution or
chemical-mechanical polishing.
26. A substrate processing method comprising: removing conductive
materials on a surface of a substrate by electrolytic processing
using a first ion exchanger; and removing a barrier layer on the
surface of the substrate with electrolytic processing using a
second ion exchanger which is other than said first ion exchanger,
electrolytic solution, chemical-mechanical polishing, or a
combination thereof.
27. The substrate processing method according in claim 25, wherein
the conductive material is copper.
28. The substrate processing method according to claim 25 wherein
the barrier layer is made of any one of TaN, Ta, TiN, and WN.
29. The substrate processing apparatus according to claim 7,
wherein said chemical-mechanical polishing section performs a
chemical-mechanical polishing using fixed abrasive member.
30. The substrate processing apparatus according to claim 8,
wherein said chemical-mechanical polishing section performs a
chemical-mechanical polishing using fixed abrasive member.
31. The substrate processing apparatus according to claim 9,
wherein said chemical-mechanical polishing section performs a
chemical-mechanical polishing using fixed abrasive member.
32. The substrate processing apparatus according to claim 7,
wherein an anti-oxidant is added in the liquid used in the
electrolytic processing section.
33. The substrate processing apparatus according to claim 8,
wherein an anti-oxidant is added in the liquid used in the
electrolytic processing section.
34. The substrate processing apparatus according to claim 9,
wherein an anti-oxidant is added in the liquid used in the
electrolytic processing section.
35. The substrate processing apparatus according to claim 7,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
36. The substrate processing apparatus according to claim 8,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
37. The substrate processing apparatus according to claim 9,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
38. The substrate processing apparatus according to claim 10,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
39. The substrate processing apparatus according to claim 11,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
40. The substrate processing apparatus according to claim 18
comprising a plurality of electrolytic processing sections with
different types of ion exchangers respectively.
41. The substrate processing apparatus according to claim 17
further comprising a chemical-mechanical polishing section for
chemically and mechanically polishing a surface of a substrate.
42. The substrate processing apparatus according to claim 18
further comprising a chemical-mechanical polishing section for
chemically and mechanically polishing a surface of a substrate.
43. The substrate processing apparatus according to claim 19
further comprising a chemical-mechanical polishing section for
chemically and mechanically polishing a surface of a substrate.
44. The substrate processing method according in claim 26, wherein
the conductive material is copper.
45. The substrate processing method according to claim 26 wherein
the barrier layer is made of any one of TaN, Ta, TiN, and WN.
46. The substrate processing method according to claim 27 wherein
the barrier layer is made of any one of TaN, Ta, TiN, and WN.
Description
TECHNICAL FIELD
[0001] This invention relates to an electrolytic processing
apparatus and a substrate processing apparatus provided with the
electrolytic processing apparatus and to a substrate processing
method, and more particularly to an electrolytic processing
apparatus useful for processing a conductive material present in
the surface of a substrate, especially a semiconductor wafer, or
for removing impurities adhering to the surface of a substrate, and
a substrate processing apparatus and method for flattening a
surface of a conductor (a conductive material) such as copper
embedded in fine concave sections for wiring provided on a surface
of a substrate such as a semiconductor wafer to form an embedded
wiring thereon.
BACKGROUND ART
[0002] In recent years, instead of using aluminum or aluminum
alloys as a material for forming interconnection circuits on a
substrate such as a semiconductor wafer, there is an strong
movement towards using copper (Cu) which has a low electric
resistance and high electromigration resistance. Copper
interconnects are generally formed by filling copper into fine
recesses formed in the 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 in the substantially the entire surface of a
substrate, followed by removal of unnecessary copper by chemical
mechanical polishing (CMP).
[0003] FIGS. 22(a) through 22(c) illustrate, in sequence of process
steps, an example of forming such a substrate W having copper
interconnects. As shown in FIG. 22(a), an insulating film 2, such
as a silicon oxide film/a film of silicon oxide (SiO.sub.2) or a
film of low-k material, is deposited on a conductive layer 1a in
which electronic apparatus are formed, which is formed on a
semiconductor base 1. A contact hole 3 and a trench 4 for
interconnects are formed in the insulating film 2 by lithography
and etching technique. Thereafter, a barrier layer 5 of TaN or the
like is formed on the entire surface, and a seed layer 7 as an
electric supply layer for electroplating is formed on the barrier
layer 5.
[0004] Then, as shown in FIG. 22(c), copper plating is provided on
the surface of the substrate W to fill the contact hole 3 and the
trench 4 with copper and, at the same time, deposit a copper film 6
on the insulating film 2. Thereafter, the copper film 6 on the
insulating film 2 is removed by chemical mechanical polishing (CMP)
so as to make the surface of the copper film 6 filled in the
contact hole 3 and the trench 4 for interconnects and the surface
of the insulating film 2 lie substantially on the same plane. An
interconnection composed of the copper film 6 as shown in FIG.
22(c) is thus formed.
[0005] Components in various types of equipments have recently
become smaller, thereby requiring a high degree of accuracy. As
sub-micro manufacturing technology has commonly been used, the
properties of materials are largely influenced by the processing
method. Under these circumstances, in such a conventional
processing method that a desired portion in a workpiece is
physically destroyed and removed from the surface thereof by a
tool, a large number of defects may be produced to deteriorate the
properties of the workpiece. It is important therefor to be able to
perform processing without deteriorating the properties of the
materials. Some processing methods, such as chemical polishing,
electrolytic processing, and electrolytic polishing, have been
developed in order to solve this problem. In contrast with
conventional physical processing, these methods perform removal
processing or the like through a chemical dissolution reaction.
Therefore, they do not suffer from defects, such as formation of an
altered layer and dislocation, due to plastic deformation, whereby
processing can be performed without deteriorating the properties of
the materials.
[0006] On the other hand, an electrolytic processing method and/or
apparatus using an ion exchanger has been developed. In this
method, as shown in FIG. 23, after an ion exchanger 512a mounted on
a processing electrode 514 and an ion exchanger 512b mounted on a
feeding electrode 516 are brought into contact with or close to a
surface of a workpiece 510, liquid 518, e.g. ultrapure water, is
supplied from a liquid supply section 519 between the processing
electrode 514 and the feeding electrode 516, and the workpiece 10,
while a voltage is applied from a power source 517 between the
processing electrode 514 and the feeding electrode 16 to thereby
performing a removing process of a surface of the workpiece.
According to this electrolytic processing, water molecules 520 in
the liquid 518 such as ultrapure water are dissociated by the ion
exchangers 512a, 512b into hydroxide ions 522 and hydrogen ions
524. The hydroxide ions 522 thus produced, for example, are
carried, by the electric field between the workpiece 510 and the
processing electrode 514 and by the flow of the liquid 518, to the
surface of the workpiece 510 opposite to the processing electrode
514 whereby the density of the hydroxide ions 522 in the vicinity
of the workpiece 510 is enhanced, and the hydroxide ions 522 are
reacted with the atoms 510a of the workpiece 510. The reaction
product 526 produced by this reaction is dissolved in the liquid
518, and removed from the workpiece 510 by the flow of the liquid
518 along the surface of the workpiece 510. Removing process of the
surface of the workpiece 510 is thus effected.
[0007] As explained above, if an electrolytic process is carried
out by disposing an ion exchanger adjacent to at least one of a
processing and feeding electrodes and a workpiece, control at the
end of process becomes difficult.
[0008] Namely, when electrolytic processing is carried out in the
state where a current flowing between a processing electrode and a
feeding electrode is controlled at a constant level, as a
principle, the processing rate is kept constant unless the area to
be processed changes, and because of this feature control during
processing becomes easier, and in addition the totalized current
value can be calculated easily, so that the amount of processing
and the processing end point can easily be grasped. In association
with the progress of polishing, however, when the barrier layer 5
comprising an insulating body (See FIG. 22) is exposed on a surface
of the wafer W upon completion of the electrolytic processing, the
area to be processed decreases depending on the line/space ratio as
well as on the wiring density, which may cause the rapid increase
in the processing rate.
[0009] Further when a conductive film such as the copper coating 6
(See FIG. 22A or FIG. 22C) as a material to be processed on a
surface of the wafer W is removed, an electric resistance value of
the conductive film becomes larger as the film thickness becomes
smaller, and therefore when electrolytic processing is carried out
keeping the current at a constant level, the loaded voltage
increases in association with the reduction of film thickness, and
the increasing rate becomes higher as a processing point comes
closer to the processing end point where the wiring pattern is
exposed on a surface of the wafer. This phenomenon occurs because
the applied voltage is inversely proportional to the film
thickness, and when the voltage rapidly increases as described
above, control over the processing end point is difficult. In
addition, when the applied voltage increases over a predetermined
value, dielectric breakdown (the so-called electric discharge)
occurs in the ultrapure water, which may cause physical damages to
a workpiece.
[0010] On the other hand, when electrolytic processing is carried
out keeping the voltage applied to between a processing electrode
and a feeding electrode at a constant level, the processing rate
rapidly drops in association with rapid reduction of the area to be
processed. Namely, in association with progress of polishing, when
the barrier layer 5 comprising an insulating body (See FIG. 22A or
FIG. 22C) is exposed on a surface of the wafer W upon completion of
the processing, the area to be processed decreases, which makes it
difficult for an electric current to flow therethrough, so that the
processing rate rapidly drops, and thus the processing rate varies,
so that it becomes difficult to detect the processing end
point.
[0011] The processing end point means, as used herein, a point of
time when processing has been carried out up to a predetermined
amount of processing for a specified section of an area to be
processed, or for any parameter correlating to the integrated
processing rate. As described above, by making it possible to
freely set a processing end point even during processing,
electrolytic processing in a multistage process is enabled.
[0012] Further, as described above, when it is attempted to remove
copper used for coating a substantially entire surface of a
substrate only by means of a chemical-mechanical polishing (CMP),
since a polishing liquid is generally used in the
chemical-mechanical polishing, not only it is required to fully
clean a semiconductor substrate contaminated by the polishing
liquid after the end of polishing, but also there occur such
problems as the cost for the polishing liquid itself as well as for
the chemicals required for cleaning, and negative influence caused
by the processing over the environment. Therefore there is a strong
need for alleviating the disadvantages of CMP.
[0013] Although a process of polishing a wafer by means of CMP
while plating is being carried as in the chemical-mechanical
polishing has been reported, when mechanical processing is applied
to a plating growth surface, sometimes abnormal growth of plating
may be promoted, which may in turn cause abnormality in the film
quality. It has also been reported that, in electrolytic processing
or in electrolytic polishing described above, processing proceeds
in association with the progress of an electro-chemical mutual
reaction between a workpiece to be processed and an electrolytic
solution (an aqueous solution of NaCl, NaNO.sub.3, HF, HCl,
HNO.sub.3, NaOH or the like). Therefore, when the electrolytic
solution containing the electrolyte as described above is used, the
workpiece to be processed will inevitably be contaminated.
[0014] Further the electrolytic processing method using an ion
exchanger and deionized water, and preferably ultrapure water has
been developed. Generally a plated substrate has fine
irregularities on the surface (plate surface), and in this
electrolytic processing method, the deionized water is present also
in the concave sections of the substrate's surface, and as the
deionized water itself is little ionized, a process for removing
unnecessary materials from the substrate barely proceeds in the
sections contacting the deionized water in the concave sections.
Therefore, the process for removing unnecessary materials proceeds
only in the sections contacting the ion exchanger containing
abundant ions therein, and the method is advantageously more
excellent in its capability for flattening a surface of a substrate
as compared to the conventional electrolytic processing method
using an electrolytic solution.
[0015] If an ion exchanger with low elasticity, namely a soft and
easily-deformable ion exchanger is used, the ion exchanger follows
the irregularities on a surface of the substrate, and it is
difficult to eliminate the irregularities on the substrate's
surface by selectively processing convex sections thereon.
SUMMARY OF THE INVENTION
[0016] The present invention has been made in the light of the
circumstances as described above, and it is an object of the
present invention to provide an electrolytic processing apparatus
having the relatively simple structure, and which making it
possible to detect a processing end point in electrolytic
processing with high reliability.
[0017] Another object of the present invention is to provide a
substrate processing apparatus and a substrate processing method
which enable a work load to be reduced in chemical-mechanical
polishing (CMP) and also enabling processing insuring high flatness
with high efficiency by replacing a part or all of the substrate
processing step carried out by using chemical-mechanical polishing
(CMP) with electrolytic processing using deionized water, and
preferably using ultrapure water.
[0018] The invention according to claim 1 provides an electrolytic
processing apparatus comprising an electrolytic processing section
having a processing electrode and a feeding electrode, for
electrolytically processing a surface of a workpiece in the
presence of a liquid by applying a voltage between the processing
electrode and the feeding electrode, and a processing end point
detecting section for detecting a processing end point by detecting
a change in a frictional force generated between the workpiece and
at least one of the processing electrode and the feeding electrode
during the processing.
[0019] As a result of the configuration described above, it is
possible to determine an amount of processing and detect a
processing end point by detecting a change in a frictional force
generated, for instance, when the workpiece contact a different
material due to a difference in friction coefficients between the
workpiece and another material, or a change in the frictional force
or any other factor generated when irregularities on a surface of
the workpiece are removed for flattening. The change in the
frictional force during processing can be detected by detecting a
change in the power provided as an input to a motor for rotating a
top ring which holds and rotates a material to be processed such as
a substrate, or for rotating a processing table.
[0020] The invention according to claim 2 provides an electrolytic
processing apparatus comprising an electrolytic processing section
having a processing electrode and a feeding electrode, for
electrolytically processing a surface of a workpiece in the
presence of a liquid by applying a voltage between the processing
electrode and the feeding electrode, and a processing end point
detecting section for detecting a processing end point by detecting
a change in an amount of heat generated between the workpiece and
at least one of the processing electrode and the feeding electrode
during the processing.
[0021] In electrolytic processing, generally heat is generated by
electric resistance of a surface of a workpiece, or because of
collisions of ions with water molecules moving in a solution
(deionized water) between a processing surface and a processed
surface. Thus, when a copper coating deposited on a surface of a
substrate is subjected to electrolytic processing under a constant
voltage, as the electrolytic processing proceeds and a barrier
layer or an insulating film is exposed, the electric resistance
becomes larger with the current value becoming smaller, so that an
amount of heat generated gradually decreases. By using this
characteristics, a processing end point can be detected by checking
a change in an amount of generated heat to determine the integrated
processing rate. A change in the amount of generated heat can be
detected, for instance, by measuring a temperature of a workpiece
such as a substrate or the like.
[0022] The invention according to claim 3 provides an electrolytic
processing apparatus comprising an electrolytic processing section
having a processing electrode and a feeding electrode, for
electrolytically processing a surface of a workpiece in the
presence of a liquid by applying a voltage between the processing
electrode and the feeding electrode, and a processing end point
detecting section for detecting a processing end point by detecting
a change in amplitude of a light reflected from a processed surface
of the workpiece.
[0023] By using this structure, it is possible to determine an
amount of processing carried out and to detect a processing end
point by detecting a change in amplitude of reflected light, which
is generated, for instance, when the workpiece is in contacts with
a different material due to a difference in reflectivity of the two
materials.
[0024] The invention according to claim 4 provides an electrolytic
processing apparatus comprising an electrolytic processing section
having a processing electrode and a feeding electrode, for
electrolytically processing a surface of a workpiece in the
presence of a liquid by applying a voltage between the processing
electrode and the feeding electrode, and a processing end point
detecting section for detecting a processing end point by detecting
a change in an eddy current generated inside the workpiece during
the processing.
[0025] When an eddy current is generated inside a conductive film
such as a copper coating, an amplitude of the eddy current changes
according to the thickness of the conductive film. Therefore it is
possible to determine an integrated (or total) processing rate and
to detect a processing end point by monitoring the eddy current
flowing inside the workpiece and detecting a change, for instance,
in the frequency.
[0026] The invention according to claim 5 provides an electrolytic
processing apparatus comprising an electrolytic processing section
having a processing electrode and a feeding electrode, for
electrolytically processing a surface of a workpiece in the
presence of a liquid by applying a voltage between the processing
electrode and the feeding electrode, and a processing end point
detecting section for detecting a processing end point by detecting
and integrating a current flowing between the processing electrode
and the feeding electrode during the processing.
[0027] In electrolytic processing, a total processing rate
(processed amount) is determined by an amount of current flowing
between an processing electrode and a feeding electrode, with a
processing rate being proportional to an integrated (total) power
consumption calculated by multiplying the amount of current by a
processed time. Therefore, it is possible to determine the
integrated (total) processing rate and detect a processing end
point by integrating the integrated power consumption calculated by
multiplying a current value by a processing time and detecting a
point of time when the integrated value reaches a predetermined
value.
[0028] The invention according to claim 6 provides a substrate
processing apparatus comprising a chemical-mechanical polishing
section for chemically and mechanically polishing a surface of a
substrate; an electrolytic processing section having a processing
electrode, a feeding electrode and an ion exchanger disposed at
least either between the substrate and the processing electrode or
between the substrate and the feeding electrode, and for
electrolytically processing a surface of the substrate in the
presence of a liquid by applying a voltage between the feeding
electrode and the processing electrode; and a top ring releasably
holding the substrate and movable between the chemical-mechanical
polishing section and the electrolytic processing section.
[0029] With this structure, it is possible to reduce a workload in
the chemical-mechanical polishing step using a polishing liquid by
sequentially executing two types of processing; one in the
chemical-mechanical polishing in the chemical-mechanical polishing
section and electrolytic processing (etching) in the electrolytic
processing section. The polishing step performed in the
chemical-mechanical polishing section and the electrolytic
processing step performed in the electrolytic processing section
may be carried out in any sequence and any number of times.
[0030] The invention according to claim 7 provides a substrate
processing apparatus comprising a chemical-mechanical polishing
section for chemically and mechanically polishing a surface of a
substrate; an electrolytic processing section having a feeding
electrode and a processing electrode, for electrolytically
processing the surface of the substrate in the presence of
deionized water or a liquid with an electric conductivity of 500
.mu.S/cm or below between the substrate and each or at least one of
the processing electrode and the feeding electrode, and applying a
voltage between the feeding electrode and the processing electrode;
and a top ring releasably holding a substrate and freely movable
between the chemical-mechanical polishing section and the
electrolytic processing section.
[0031] It is preferable to use deionized water with the electric
conductivity of 10 .mu.S/cm or below (as converted to latm, 25.mu.,
which is applicable also hereinafter), and is more preferable to
use ultrapure water having an electric conductivity of 0.1 .mu.S/cm
or below. As described above, by carrying out electrolytic
processing with deionized water, and preferably with ultrapure
water, it is possible to process a surface of a workpiece cleanly
without leaving any impurities, and also to simplify the cleaning
step after the electrolytic processing.
[0032] When deionized water or preferably ultrapure water is used,
each water molecule in the deionized water (ultrapure water) is
dissociated to OH.sup.- and H.sup.+ through a catalytic reaction
with an ion exchanger, and for instance, the generated OH.sup.- is
removed to the processing electrode side along the electric field
and through a flow of deionized water (ultrapure water), and an OH
radical generated when an electric charge of the OH-- ion is
delivered to the processing electrode at a position closed thereto
is supplied to a workpiece, thereby enabling processing for
removing unnecessary materials to be carried out.
[0033] Further, it is possible to use an electrolytic solution with
the electric conductivity of 500 .mu.S/cm or below, preferably of
50 .mu.S/cm or below, and more preferably of 0.1 .mu.S/cm or below
prepared by adding an additive such as a surface active agent to
the deionized or ultrapure water. A solution of, for instance, a
neutral salt of NaCl or Na.sub.2SO.sub.4, an acid such as HCl or
H.sub.2SO.sub.4, or an alkali such as ammonia may be used as the
electrolytic solution by selecting any of those described above at
need.
[0034] The invention according to claim 8 provides a substrate
processing apparatus comprising a chemical-mechanical polishing
section for chemically and mechanically polishing a surface of a
substrate; an electrolytic processing section having a processing
electrode, a feeding electrode and an ion exchanger disposed at
least either between the substrate and the processing electrode or
between the substrate and the feeding electrode, for
electrolytically processing the surface of the substrate in the
presence of a liquid by applying a voltage between the feeding
electrode and the processing electrode; one or more top rings for
releasably holding the substrate; and a pusher located between said
chemical-mechanical polishing section and said electrolytic
processing section and transferring the substrate between the
chemical-mechanical polishing section and the electrolytic
processing section.
[0035] With this structure, by delivering or receiving a substrate
with the pusher, chemical-mechanical polishing in the
chemical-mechanical polishing section and electrolytic processing
(etching) in the electrolytic processing section can sequentially
be carried out.
[0036] The invention according to claim 9 provides a substrate
processing apparatus comprising a chemical-mechanical polishing
section for chemically and mechanically polishing a surface of a
substrate; an electrolytic processing section having the feeding
electrode and a processing electrode, for electrolytically
processing the surface of the substrate in the presence of
deionized water or a liquid with an electric conductivity of 500
.mu.S/cm or below to at least either between the substrate and the
processing electrode or between the substrate and the feeding
electrode; one or more top rings for releasably holding the
substrate; and a pusher located between said chemical-mechanical
polishing section and said electrolytic processing section and for
transferring the substrate between the chemical-mechanical
polishing section and the electrolytic processing section.
[0037] The invention according to claim 10 provides a substrate
processing apparatus according to any one of claims 6 to 9, wherein
said chemical-mechanical polishing section performs a
chemical-mechanical polishing using fixed abrasive member.
[0038] As described above, by using fixed abrasive member and
carrying out chemical-mechanical polishing with a solution prepared
by adding an additive such as a surface active agent to deionized
water or ultrapure water not containing abrasive member therein, an
amount of use of a polishing solution which troublesome to use and
expensive can be reduced.
[0039] The invention according to claim 11 provides a substrate
processing apparatus according to any one of claims 6 to 9, wherein
an anti-oxidant is added in the liquid used in the electrolytic
processing section.
[0040] The invention according to claim 12 provides a substrate
processing apparatus according to any one of claims 6 to 11,
wherein a plurality of polishing tables are provided in the
chemical-mechanical polishing section.
[0041] The invention according to claim 13 provides a method for
processing a substrate using three or more process stages
comprising polishing a surface of the substrate by
chemical-mechanical polishing; and removing unnecessary portions
from the surface of the substrate by electrolytic processing using
deionized water or ultrapure water or liquid with an electric
conductivity of 500 .mu.S/cm or below.
[0042] In electrolytic processing, when a value of a current
supplied to between a feeding electrode and a processing electrode
is large, also the processing rate becomes larger (When the current
value is small, also the processing rate is smaller). On the other
hand, when a voltage between the feeding electrode and the
processing electrode is high, a value of the current flowing
between the processing electrode and the feeding electrode becomes
larger, and as a result the processing rate (processed amount)
becomes larger. Therefore, it is possible to adjust the processing
rate to an optimal value by freely changing (for instance, from
time to time) at least one of the voltage or the current between
the processing electrode and the feeding electrode according to the
processing stage (or situation).
[0043] Further by concurrently executing the conventional type of
chemical-mechanical polishing (CMP) and electrolytic processing
with deionized water, a solution with the electric conductivity of
500 .mu.S/cm or below, or an electrolytic solution, the workload in
the chemical-mechanical polishing can be reduced. Further the step
of chemical-mechanical polishing and the step of etching by means
of electrolytic processing may be carried out in any order and any
times.
[0044] The invention according to claim 14 provides a method for
processing a substrate using three or more process stages
comprising polishing a surface of the substrate by
chemical-mechanical polishing; and removing unnecessary portions of
the substrate by electrolytic processing placing an ion exchanger
at least either between the substrate and an processing electrode
or between the substrate and the feeding electrode and applying a
voltage between the feeding electrode and the processing electrode
in the presence of deionized water, a liquid with an electric
conductivity of 500 .mu.S/cm or below, or an electrolytic
solution.
[0045] The invention according to claim 15 a method for processing
substrate comprising polishing a surface of the substrate by
chemical-mechanical polishing using a fixed abrasive member; and
removing unnecessary portions of the substrate with deionized water
or ultrapure water or liquid with an electric conductivity of 500
.mu.S/cm or below.
[0046] Using this method, it is possible, for instance, to remove a
copper layer formed on a surface of a substrate by carrying out
chemical-mechanical polishing and electrolytic processing and, when
a barrier metal (a barrier layer) comprising, for instance, TaN, is
exposed, by removing the barrier metal by means of
chemical-mechanical polishing.
[0047] The invention according to claim 16 provides a substrate
processing apparatus comprising a plurality of electrolytic
processing sections, each of said electrolytic processing sections
having a feeding electrode and a processing electrode, for
electromechanically processing a surface of a substrate by
supplying a fluid to at least either between the substrate and the
processing electrode or between the substrate and the feeding
electrode and supplying a voltage to between the feeding electrode
and the processing electrode. As a result of this feature, it is
possible to carry out electrolytic processing using different
processing characteristics with ion exchangers having different
characteristics or belonging to a different type in a plurality of
electrolytic processing sections.
[0048] The invention according to claim 17 provides a substrate
processing apparatus according to claim 16, wherein an ion
exchanger is provided at least either between the substrate and the
processing electrode or between the substrate and the feeding
electrode in at least one of the plurality of electrolytic
processing sections.
[0049] The invention according to claim 18 provides a substrate
processing apparatus according to claim 16, wherein an ion
exchanger is provided at least either between the substrate and the
processing electrode or between the substrate and the feeding
electrode in all of the plurality of electrolytic processing
sections.
[0050] The invention according to claim 19 provides a substrate
processing apparatus according to claim 17 or 18 comprising a
plurality of electrolytic processing sections with different types
of ion exchangers respectively. Because of this feature, for
instance, polishing for eliminating steps on a substrate of a
substrate can be carried out in an electrolytic processing section
using an ion exchanger with high elasticity, and then polishing for
removing unnecessary portions of the substrate can be carried out,
after the steps have been removed, in an electrolytic processing
section using an ion exchanger with low elasticity.
[0051] The invention of claim 20 provides a substrate processing
apparatus according to any one of claims 16 to 19 further
comprising a chemical-mechanical polishing section for chemically
and mechanically polishing a surface of a substrate.
[0052] As a result of this feature, it is possible to efficiently
carry out processing requiring different processing conditions from
those required in the electrolytic processing section for removing,
for instance, a barrier metal (a barrier layer). The barrier metal
can be processed and removed by means of chemical-mechanical
polishing (CMP) using a polishing pad and slurry.
[0053] The invention according to claim 21 provides a substrate
processing apparatus comprising an ion exchanger holding member for
holding an ion exchanger; an electrolytic processing section having
a processing electrode, a feeding electrode and an ion exchanger
disposed at least either between the substrate and the processing
electrode or between the substrate and the feeding electrode, for
electrolytically processing a surface of the substrate in the
presence of a liquid by applying a voltage between the feeding
electrode and the processing electrode; and an ion exchanger
replacement means for replacing the ion exchanger holding member in
the electrolytic processing section with another ion exchanger
holding member.
[0054] As a result of the features described above, by exchanging
an ion exchanger in the electrolytic processing section with
another one via, for instance, the cartridge type of ion exchanger
for holding an ion exchanger, it is possible to carry out different
types of electrolytic processing under different conditions in a
single electrolytic processing section.
[0055] The invention according to claim 22 provides a substrate
processing apparatus according to claim 21, wherein said
electrolytic processing section has a plurality of ion exchanger
holding members.
[0056] The invention according to claim 23 provides a substrate
processing method for electrolytically processing a surface of a
substrate through a multi-stage process in the presence of a
liquid, an ion exchanger at least between a substrate and the
processing electrode or between the substrate and the feeding
electrode, and a voltage applied between the processing electrode
and the feeding electrode, the method comprising electrolytically
processing the substrate using a first ion exchanger; and
electrolytically processing the substrate using a second ion
exchanger, wherein said first ion exchanger has high elasticity
than that of said second ion exchanger.
[0057] The invention according to claim 24 provides a substrate
processing method for removing unnecessary portions of a surface of
a substrate by using a plurality of steps of carrying out
electrolytic processing by placing an ion exchanger at least
between the substrate and the processing electrode or between the
substrate and the feeding electrode, applying a voltage between the
processing electrode and the feeding electrode, and causing a
relative movement between the substrate and at least one of the
processing electrode and the feeding electrode in the presence of a
ultrapure water, deionized water or a fluid with an electric
conductivity of 500 .mu.S/cm or below; carrying out electrolytic
processing by applying a voltage between the processing electrode
and the feeding electrode and also causing a relative movement
between the substrate and at least one of the processing electrode
and the feeding electrode in the presence of an electrolytic
solution; and carrying out polishing by chemical-mechanical
polishing.
[0058] The invention according to claim 25 provides substrate
processing method as descrimember in claim 24 further comprising
removing conductive materials on the surface of the substrate by
electrolytic processing using an ion exchanger; and removing a
barrier layer on the surface of the substrate by either
electrolytic processing with an electrolytic solution or
chemical-mechanical polishing.
[0059] The invention according to claim 26 provides a substrate
processing method comprising removing conductive materials on a
surface of a substrate by electrolytic processing using a first ion
exchanger; and removing a barrier layer on the surface of the
substrate with electrolytic processing using a second ion exchanger
which is other than said first ion exchanger, electrolytic
solution, chemical-mechanical polishing, or a combination
thereof.
[0060] The invention according to claim 27 provides a substrate
processing method according to claim 25 or 26, wherein the
conductive material is copper.
[0061] The invention according to the present invention provides
the substrate processing method according to any one of claims 25
to 27, wherein the barrier layer is made of any of TaN, Ta, TiN,
and WN.
[0062] The disclosure by the application of PCT/JP02/01545
"ELECTROLYTIC PROCESSING DEVICE AND SUBSTRATE PROCESSING APPARATUS"
is incorporated herein by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0063] FIG. 1 is a flat view showing a substrate processing
apparatus according to a first embodiment of the present
invention;
[0064] FIG. 2 is a front view showing the substrate processing
apparatus according to a first embodiment of the present
invention;
[0065] FIG. 3 is a block diagram showing the entire configuration
of a substrate processing system equipped with the substrate
processing apparatus shown in FIG. 1 or FIG. 2;
[0066] FIG. 4 is a cross-sectional view showing a key section of an
electrolytic processing section according to another embodiment of
the present invention;
[0067] FIG. 5 is a graph showing relation;
[0068] FIG. 6 is a cross-sectional view showing a key section of an
electrolytic processing according to a further different embodiment
of the present invention;
[0069] FIG. 7 is a cross-sectional view showing a key section of
the electrolytic processing section according to a still further
different embodiment of the present invention;
[0070] FIG. 8 is a front view showing a substrate processing
apparatus according to a second embodiment of the present
invention;
[0071] FIG. 9 is a front view showing a substrate processing
apparatus according to a third embodiment of the present
invention;
[0072] FIG. 10 is a front view showing a substrate processing
apparatus according to a fourth embodiment of the present
invention;
[0073] FIG. 11 is a flat view showing a substrate processing
apparatus according to a fifth embodiment of the present
invention;
[0074] FIG. 12 is a flat view showing a substrate processing
apparatus according to a sixth embodiment of the present
invention;
[0075] FIG. 13 is a front view showing the substrate processing
apparatus shown in FIG. 12;
[0076] FIG. 14 is a flat view showing a substrate processing
apparatus according to a seventh embodiment of the present
invention;
[0077] FIG. 15 is a flat view showing a substrate processing
apparatus according to an eighth embodiment of the present
invention;
[0078] FIG. 16 is a front view showing the eighth embodiment of the
present invention;
[0079] FIG. 17 is a block diagram showing the entire configuration
of the substrate processing system equipped with the substrate
processing apparatus shown in FIG. 15 and FIG. 16;
[0080] FIG. 18 is a flat view showing a substrate processing
apparatus according to a ninth embodiment of the present
invention;
[0081] FIG. 19 is a partially cut front view showing an
electrolytic processing section of a substrate processing apparatus
according to a tenth embodiment of the present invention;
[0082] FIG. 20(a) and FIG. 20(b) are views each showing the state
where an ion exchanger holder section is mounted in a electrode
section of the substrate processing apparatus according to the
tenth embodiment of the present invention;
[0083] FIG. 21 is a block diagram showing the entire configuration
of a substrate processing system equipped with the substrate
processing apparatus shown in FIG. 19 and FIGS. 20(a) and
20(b);
[0084] FIG. 22(a) to FIG. 22(c) are views each showing a step of
forming copper wiring in the sequential order respectively; and
[0085] FIG. 23 is a view illustrating a principle of electrolytic
processing with an ion exchanger.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0086] Embodiments of the present invention are described below
with reference to the drawings. It should be noted that, although
the example shown in FIG. 22B is a case where wiring comprising a
copper coating 6 is formed as shown in FIG. 22C, by removing the
copper coating 6 and a barrier metal 6 deposited on an insulating
film 2 to align a surface of the copper coating filled in a contact
hole 3, as well as in a groove 4 for wiring with a surface of the
insulating film 2 almost on the same plain, the present invention
can be applied to a coating made of a material other than
copper.
[0087] FIG. 1 and FIG. 2 show a substrate processing apparatus
having an electrolytic processing apparatus according to a first
embodiment of the present invention and a chemical-mechanical
polishing apparatus, and FIG. 3 shows the entire configuration of a
substrate processing system having the substrate processing
apparatus 10. As shown in FIG. 3, the substrate processing system
comprises a pair of load/unload sections as a carrying in/out
section for carrying in or out a cassette with a substrate W having
copper coating 6 as a conductive coating (a workpiece) on a surface
thereof; a reversing unit 14 for reversing the substrate W; a
pusher 16 for receiving or delivering a substrate; a cleaning
apparatus 18; and a substrate processing apparatus 10. Further
provided at a position surrounded by the load/unload section 12,
the reversing unit 14, pusher 16, and cleaning device 18 is a
running type of carrier robot. Further there is provided a control
section 22 for providing various types of controls for controlling
a voltage applied to between a processing electrode 44 and a
feeding electrode 46 each described below or a current flowing
between the processing electrode and the feeding electrode when
electrolytic processing is performed by the substrate processing
apparatus 10.
[0088] As shown in FIG. 1 and FIG. 2, the substrate processing
apparatus 10 comprises a chemical-mechanical polishing section 24
for chemically and mechanically polishing a surface of a substrate;
an electrolytic processing section 26 for etching a surface of a
substrate by means of electrolytic processing with ultrapure water
or deionized water; and a carrier section for removably holding a
substrate and carrying the substrate between the
chemical-mechanical polishing section 24 and the electrolytic
processing section 26; and the chemical-mechanical polishing device
24 and the carrier section 28 forming a CMP device, while the
electrolytic processing section 26 and the carrier section 28
forming an electrolytic processing device. Namely, the carrier
section 28 functions as a carrier section for both the electrolytic
processing device and the CMP device.
[0089] The chemical-mechanical polishing section 24 comprises a
rotatable polishing table 30 and polishing pad 32 adhered to a top
surface of this polishing table 30, and an abrasive solution nozzle
36 for supplying an abrasive solution (a polishing solution) 34 to
the polishing pad 32 is provided above the polishing table 30. The
commercially available polishing pad includes, for instance, SUBA
800, and IC-1000 or the like manufactured by Rodel Corp. In the
chemical-mechanical polishing, a substrate is made flat using an
abrasive coating. Between the polishing table 30 and the substrate
W, it is required that a relative movement be possible, while such
movements as rotation, scrolling (translational rotation), and
reciprocal linear movement are allowable for the polishing table
30.
[0090] The electrolytic processing section 26 has a processing
table 42 which can perform such movements as orbital motion, and
so-called scrolling (translational rotation). This processing table
is made of an insulating material, and the processing electrodes 44
and the feeding electrodes 46 each having a fan-like shape are
alternately embedded on a top surface of this processing table 42
along the periphery, and ion exchangers are placed on the
processing electrode 44 and the feeding electrodes 48. Further
provided inside a hollow motor 40 is a deionized water feed pipe
(not shown) extending from the outside, and a throughhole opened on
a top surface of the processing table 42 and communicating with
this deionized water feed pipe is provided at a center of the
processing table 42. Because of this configuration, deionized or
preferably ultrapure water is supplied through the deionized water
feed pipe and the throughhole to ion exchangers 48 placed on the
processing table 42.
[0091] Herein, the deionized water is water with the electric
conductivity of, for instance, 10 .mu.S/cm or below (as converted
to 1 atm, 25.mu., which is applicable also hereinafter), while the
ultrapure water is water with an electric conductivity of 0.1
.mu.S/cm. It should be noted that a liquid with an electric
conductivity of 500 .mu.S/cm or below, any type of electrolytic
water, and an anti-oxidant (such as BAT; benzotriazole) may be
added in place of the deionized water or preferably in place of the
ultrapure water. By supplying an electrolytic solution and/or
adding an anti-oxidant (such as, for instance, benzotriazole(BTA))
during processing, instability in processing due to products
generated during processing or generation of a gas can be removed,
so that homogeneous processing with excellent reproducibility can
be realized. The BTA forms a thin film on a surface of various
types of metals. In the electrolytic processing according to the
present invention, the formed coating can be removed by means of
the scrub effect of the ion exchanger, so that a surface of a metal
with no exposed oxide film being formed thereon can be contacted
with an processing electrode or an ion exchanger on the processing
electrode.
[0092] In this example, a plurality of electrode plates 50 each
having a form like a fan are arranged on a top surface of the
processing table 42 along the periphery, and when a cathode and an
anode of a power supply unit 52 are alternately connected to the
electrode plates 50, the electrode plates 50 connected to the
cathode of the power supply unit 52 function as processing
electrode 44 respectively, while the electrode plates 50 connected
to the anode function as feeding electrodes 46 respectively. This
effect can be achieved because, for instance, in case of copper,
the electrolytic processing effect occurs in the cathode side, and
in some types of materials to be processed, the configuration is
allowable in which the cathode side functions as a feeding
electrode and the anode side functions as a processing electrode.
Namely, when the material to be processed is, for instance, copper,
molybdenum, or iron, the electrolytic processing effect occurs at
the cathode side, so that a configuration is possible in which the
electrode plates 50 connected to the cathode of the power supply
unit 52 function as processing electrode and the electrode plates
50 connected to the anode function as the feeding electrodes 46
respectively. On the other hand, when the material to be processed
is aluminum or silicon, the electrolytic processing effect occurs
in the anode side, so that the electrodes connected to the anode of
the power supply unit function as processing electrodes and those
connected to the cathode function as the feeding electrodes
respectively.
[0093] The ion exchanger 48 comprises, for instance, a non-woven
cloth with an anion exchange function or a cation exchange function
given thereto. The cation exchanger preferably carries a strongly
acidic group (such as a sulfonic group) thereon, but may carry a
weakly acidic group (such as a carboxylic group) thereon. The anion
exchanger preferably carries an anion exchanging group comprising a
strongly acidic group (a quarternary group), but may carry an anion
exchanging group comprising a weakly acidic group (a tertiary or
lower grade amino group).
[0094] The non-woven cloth, for instance, with a strongly acidic
group anion exchanging function given thereto is prepared by
introducing a graft chain by means of the so-called radioactive ray
graft polymerization method, in which graft polymerization is
performed after irradiation of .gamma. ray, into the non-woven
cloth made of polyolefin with the textile diameter from 20 to 50
.mu.m and with the void ratio of about 90%, and then aminating the
introduced graft chain to introduce an quarternary ammonium group.
A quantity of the introduced ion exchanging groups is decided
according to a quantity of graft chains to be introduced. For
carrying out graft polymerization, a monomer of such materials as
acrylic acid, styrene, glycidyl methacrylate, sodium styrene
sulfonate, and chloromethyl styrene may be used, and a quantity of
graft chains used for polymerization can be controlled by
controlling a concentration of the monomer, the reaction
temperature, and the reaction time. The ratio of the material of
weight after the graft polymerization against the weight after the
graft polymerization is called a graft ratio, and a graft ratio up
to 500% is allowable, and a maximum quantity of the ion exchanging
groups introduced after the graft polymerization up to 5 meq/g is
allowable.
[0095] The non-woven cloth with a strongly acidic cation exchanging
function imparted thereto is prepared, as in the method of imparted
the strongly acidic group anion exchanging function, by introducing
a graft chain by means of the so-called radioactive ray graft
polymerization method, in which graft polymerization is performed
after irradiation of y ray, into the non-woven cloth made of
polyolefin with the textile diameter from 20 to 50 .mu.m and with
the void ratio of about 90%, and then processing the introduced
graft chain, for instance, with hot sulfuric acid to introduce a
sulfonic acid group therein. When the introduced graft is processed
with hot phosphoric acid, a phosphoric acid group can be
introduced. Herein, this graft ratio is allowable up to 500%, and
the maximum quantity of the ion exchanging groups introduced after
the graft polymerization is allowable up to 5 meq/g.
[0096] As a material for the ion exchanger 48, a polyolefin-based
polymer such as polyethylene, polypropylene, or other organic high
polymer may be used. The forms of the ion exchanger 48 may include,
in addition to the non-woven cloth, a woven cloth, a sheet, a
porous material, a net, and a short fiber.
[0097] A raw material made of polyethylene or polypropylene can be
at first radical-polymerized by irradiating (pre-irradiation)
radioactive rays (r ray and an electron beam) to it, and then can
be graft-polymerized by reacting it with monomers. With this
processing, homogenous graft chain with little impurities can be
produced. On the other hand other organic high polymer materials
can be radical-polymerized by at first by impregnating monomers
thereto and then irradiating radioactive rays (.gamma. ray, an
electron beam, and ultraviolet rays) (simultaneously). This method
may be applied to almost all materials, although homogeneity in the
final product is slightly lower as compared to that produced when
polyethylene or polypropylene is used.
[0098] By forming the ion exchanger 48 with non-woven cloth with
the anion exchanging function or cation exchanging function
assigned thereto as described above, it becomes possible for a
solution such as deionized water, ultrapure water, or an
electrolytic solution to freely move inside the non-woven cloth and
easily reach a degree of activity where a catalytic action for
dissociating water inside the non-woven cloth is realized, so that
many water molecules are dissociated into hydrogen ions and
hydroxide ions. Further the hydroxide ions are efficiently carried
to a surface of the processing electrode 44 in association with
movement of the solution such as deionized water, ultrapure water,
and the electrolytic solution generated in dissociation, so that a
large current can be obtained even with a low voltage applied
thereto.
[0099] Further, as shown in FIG. 1, a regenerating section 54 for
regenerating the ion exchanger 48 is provided at the side of the
processing table 42. This regenerating section 54 comprises an
oscillating arm 56, and a regeneration head 58 held at a free edge
of this oscillating arm 56. The ion exchanger 48 can be regenerated
during processing by applying a voltage reverse to that applied
during processing to the ion exchanger 48 from the power supply
unit 52 (See FIG. 2) for promoting dissolution of materials such as
copper deposited on the ion exchanger 48. In this case, the
regenerated ion exchanger 48 is rinsed with deionized water or
ultrapure water supplied to a top surface of the processing table
42.
[0100] The hollow motor 40 is connected to an inverter 410 as shown
in FIG. 2, and an AD power converted to that having a desired
frequency and a desired voltage is supplied from a utility AD power
source 412 via a connection table 414 to the hollow motor 40. The
processing table 42 rotates at a rotating speed suited to the
predetermined conditions for electrolytic processing. A current
converter 416 and a voltage converter 418 are connected to the
connection table 414, and output from these converters are provided
as input to a power meter 420. The input power to the hollow motor
40 detected by the power meter 420 is reported to a signal
processor 422, which is a processing end point detecting section,
and this signal processor 422 determines whether a change in the
input power into the hollow motor 40 is larger than the
predetermined value or not. Namely the input power to the hollow
motor 40 changes in association with a change in the frictional
force generated between the substrate W and processing electrode 44
or feeding electrode 46, and therefore by detecting a change in the
input power into the hollow motor 40, a change in the frictional
force between the substrate W and the processing electrode 44 and
between the substrate W and the feeding electrode 46 is detected to
determine the integrated processing rate for detecting the
processing end point.
[0101] Although the above description assumes a case where the
power supplied to the hollow motor 40 for driving and rotating the
processing table 42 is detected, an alternate is allowable in which
a power supplied to a top ring rotation motor 82 for driving and
rotating the top ring 74.
[0102] The carrier section 28 is placed between the
chemical-mechanical polishing section 24 and the electrolytic
processing section 26 and has a pivot shaft 62 which rotates when
driven by the swivel motor 60 attached at a lower end thereof. This
pivot shaft 62 is equipped with a elevating board 66 which moves
vertically in the axial direction in accordance with the movement
of the elevating motor 64 attached to an upper end thereof. A base
edge section of the top ring head 68 extending in the horizontal
direction is fixed to the elevating board 66. Provided at a free
end of this top ring head 68 is an elevating shaft 72, and to a
lower edge of this elevating shaft 72 is linked a top ring 74 for
detachably holding a substrate W via a ball joint 76 in such a
manner as to allow free tilting.
[0103] In parallel with the elevating shaft 72, a cylinder 78 is
set which presses the substrate W held by the top ring 74 via the
elevating shaft 72 toward the polishing surface 32A on the
polishing table 30 with the predefined pressure. Further, a timing
belt 86 is provided to bridge the driven pulley 80 which is
attached to the shaft 72 and the driving pulley 84 which is fixed
to the driving shaft of the top ring swivel motor 82, enabling the
top ring 74 to rotate monolithically with the elevating shaft 72 in
accordance with rotation of the motor 82.
[0104] By this movement, the top ring head 68 is oscillated to move
the top ring 74 toward directly above the pusher 16 shown in FIG. 3
for raising the pusher 16, and receives the substrate W from the
pusher 16. Then, in the state where the substrate W is held by the
top ring 74, the top ring head 68 is oscillated to make the top
ring 74 move toward a position above the polishing table 30.
Subsequently, the top ring 74 is caused to descend and the
substrate W held by the top ring 74 via the cylinder 78 is pressed
under a predetermined pressure toward the polishing surface 32a on
the polishing table 30 and at the same time the polishing table 30
and the top ring 74 are rotated to supply an abrasive solution from
the abrasive solution nozzle 36 to the polishing pad 32. With the
operations described above, the chemical-mechanical polishing of
the surface (undersurface) of the substrate W is performed.
[0105] Further in the state where the substrate W is held by the
top ring 74, the top ring head 68 is oscillated and the top ring 74
is moved to a position above the processing table 42. Then, the top
ring 74 is descended to move the substrate W held by the top ring
74 to a position close to or in direct contact with the ion
exchanger 48 on the processing table 42. Under this condition, both
the processing table 42 and the top ring 74 are rotated to supply
deionized water or preferably ultrapure water to the ion exchanger
48 on the upper surface of the processing table 42, and
concurrently a voltage is applied to between the processing
electrode 44 and the feeding electrode 46. By this process,
electrolytic processing (etching) of the top surface (or
undersurface) of a substrate is carried out.
[0106] Next processing (electrolytic processing) of a substrate by
this substrate processing system is described below. The example
described below assumes a case where, for instance, when a barrier
metal (barrier layer) 5 comprising TaN is exposed, the barrier
metal 5 is chemically and mechanically removed by
chemically-mechanically polishing a surface of a substrate W held
by the top ring 74 and then electrolytically processing the surface
for etching, and further chemically-mechanically polishing the
surface to remove the copper coating 6 formed on the surface of the
substrate W by means of the combination of the chemical-mechanical
polishing and electrolytic processing. It is needless to that that
the chemical-mechanical polishing step and the electrolytic
processing step may be performed in any sequence and any number of
times.
[0107] At first, as shown in FIG. 22(b), a sheet of substrate W is
taken out from a cassette by the carrier robot 20 accommodating
therein the substrate W with a copper coating (conductive material)
6 formed as a conductive film (a section to be processed) shown in
FIG. 22(b) and set on the load/unload section 12, and the substrate
W is transferred to the reversing machine 14 to be reversed therein
so that the top surface of the substrate W with the copper coating
6 formed thereon faces downward. Then the substrate W with the
surface facing downward is carried to the pusher 16 by the carrier
robot 20 to be placed on the pusher 16. Then, the top ring head 68
is oscillated to move the top ring 74 to a position directly above
the pusher 16, and in that state the pusher 16 is raised and the
substrate W on the pusher 16 is sucked and held by the top ring
74.
[0108] Next, in the state where the substrate W is held by the top
ring 74, the top ring 74 is moved to a position above the polishing
table 30 by oscillating the top ring head 68. Then, the top ring 74
is caused to descend, and the substrate W held by the top ring 74
is pressed to the polishing surface 32a onto the polishing table 30
via the cylinder 78 under a predetermined force. In this state, the
polishing table 30 and the top ring 74 are rotated, and at the same
time, an abrasive solution is supplied from the abrasive solution
nozzle 36 to the polishing pad 32 and the chemical-mechanical
polishing is carried out for the undersurface of the substrate W.
When the thickness of the copper film 6 is detected to have reached
the desired level, the top ring 74 is raised with rotation of the
polishing table 30 and the top ring 74 stopped, and further supply
of the abrasive solution is stopped, thus the chemical-mechanical
polishing being terminated.
[0109] Then, in the state where the top ring 74 is holding the
substrate W, the top ring head 68 is oscillated to move the top
ring 74 to a position above the processing table 42. After this
operation, the top ring 74 is caused to descend to move the
substrate W held by the top ring 74 to a position extremely close
to or directly in contrast with the ion exchanger 48 on the
processing table 42, and in this state, the processing table 42 and
the top ring 74 are rotated, and at the same time, the deionized
water or preferably the ultrapure water is supplied to the ion
exchanger 48 on the top surface of the processing table 42, thus
the electrolytic processing (etching) being carried out to the top
surface (undersurface) of the substrate W by applying a voltage to
between the processing electrode 44 and the feeding electrode
46.
[0110] In brief, by the actions of hydrogen ion or hydroxide ions
generated by the ion exchanger 48, the electrolytic processing of
the copper coating 6 formed on the substrate W is performed, and
efficient electrolytic processing can be performed by enabling
deionized water or preferably ultrapure water to smoothly flow
through the ion exchanger 48 to generate a large amount of hydrogen
ions and hydroxide ions, and supplying the ions to the surface of
the substrate W.
[0111] In this process, a processing efficiency can be improved by
making deionized water, or preferably ultrapure water freely flow
through inside of the ion exchanger 48 to sufficiently supply water
to the functional groups (or sulfonic groups in the case of a
strongly acidic cation exchanger material) capable of promoting
dissociation of water molecules and removing the processing
products (including gas) generated through a reaction with
hydroxide ions (or OH radicals) with the flow of the water.
Therefore, the flow of the deionized, or more preferably the
ultrapure water is required and the flow of the deionized or more
preferably the ultrapure water should preferably be constant and
even for achieving the uniformity and homogeneity in ion supply,
removal of processing products as well as in the processing
efficiency.
[0112] In this step, a voltage applied to or current flowing
between the processing electrode 44 and the feeding electrode 46 is
controlled in the control section 22 to adjust the processing rate
to the optimal value, and when, for example, the exposure of the
barrier metal 5 comprising TaN or the like is detected, the
electrolytic processing is finished. Generally, when the voltage
applied to between the processing electrode 44 and the feeding
electrode 46 is high, a value of the current flowing between the
processing electrode 44 and the feeding electrodes 46 becomes
larger, and as a result also the processing rate (processed amount)
becomes higher. Therefore, it is possible to adjust the processing
rate to an optimal value by varying (for example from time to time)
at least either one of the voltage or the current applied between
the processing electrode 44 and the feeding electrode 46, the
processing rate can be adjusted to the optimal level.
[0113] At the same time, the power into the hollow motor 40 is
detected with a power meter 420, and whether the power variation is
kept within the predetermined range or not is determined by a
signal processor 422, and thereby the fact that the barrier layer 5
comprising TaN or the like has been exposed to a top surface of the
substrate W, when the processing end position is detected. Namely,
when the barrier layer 5 comprising TaN or the like has been
exposed on a top surface of the substrate W, the frictional force
generated between the substrate W and the processing electrode 44
or between the substrate W and the feeding electrode 46 starts
changes, and also input power to the hollow motor 40 is changed. By
detecting the change in the input power to the hollow motor 40, it
is determined that the barrier layer 5 comprising TaN or the like
has been exposed on a surface of the substrate W, and the point is
regarded as the processing end point. After completion of the
electrolytic processing, the power supply 74 is disconnected with
the top ring 74 raised upward, and the rotation of the processing
table 42 and the top ring 74 is stopped.
[0114] Next, in the state where the substrate W is held by the top
ring 74, the top ring head 68 is oscillated as described above to
move the top ring 74 to a position above the polishing table 30,
and then the substrate W being held by the top ring 74 is pressed
with a prescribed pressure to the polishing surface 32a of the
polishing table 30 and the polishing table 30 and the top ring 74
are concurrently rotated with the abrasive solution supplied to the
polishing pad 32 from the abrasive solution nozzle 36, thus a top
surface (or undersurface) of the substrate W being
chemically-mechanically polished.
[0115] Then, as shown in FIG. 22(c), a top surface of the copper
coating 6 filled in the contact hole 3 as well as in the groove 4
for wiring and the surface of the insulation coating 2 are
positioned on the almost same plain, and when it is detected that
the wiring comprising the copper coating 6 is completed, the top
ring 74 is raised with the rotation of the polishing table 30 and
the top ring 74 stopped, and further the supply of the abrasive
solution is stopped to terminate the chemical-mechanical
polishing.
[0116] After the polishing is finished, the substrate W is
delivered to the pusher 16 by oscillating the top ring head 68. The
carrier robot 20 receives the substrate W from the pusher 16,
carries it to the reversing unit 14 to reverse it therein, if
necessary, and then carries it to the cleaning device 18 to subject
the substrate to cleaning and drying, and finally the substrate W
is returned to the cassette in the load/unload section 12.
[0117] The example described above assumes a case where deionized
water, or more preferably ultrapure water is supplied to
electrolytic processing section 26. By performing the electrolytic
processing using deionized or more preferably ultrapure water
containing no electrolyte, deposition of impurities such as extra
electrolyte on the surface of the substrate W will be avoided, and
if deposition occurs, the impurities can completely be removed.
Furthermore, the ion exchanger 48 immediately captures, by the ion
exchange reaction, copper ions and the like which have been
dissolved during the electrolytic processing, there will be no
further precipitations of copper ion or the like on the surface of
the substrate W or on any other parts and no contamination will
occur on the surface of the substrate W because of formation of
fine particles by oxidization.
[0118] As the ultrapure water has a high specific resistance and a
current hardly flows smoothly therethrough, so that the distance
between the electrode and the workpiece is set to a small value or
an ion exchanger is inserted between the electrode and the
workpiece to reduce resistance, but reduction in power can also be
achieved by using an electrolytic solution concurrently to reduce
the electric resistance. In the case of processing with an
electrolytic solution, the area to be processed in the workpiece
tends to cover a slightly wider area than that in the processing by
electrode processing. However, when processing is performed with a
combination of ultrapure water and the ion exchanger, no
electricity runs in the ultrapure water so that the processing is
limited only to the area where the processing electrode of the
workpiece and the ion exchanger are projected.
[0119] Further, in place of the deionized water or the ultrapure
water, an electrolytic solution prepared by adding electrolyte in
deionized water or ultrapure water may also be used. By using an
electrolysis solution, further reduction of power consumption can
be achieved as the specific resistance is further lowered. As the
electrolytic solution, for instance, solutions of neutral salts
such as NaCl, Na.sup.2SO.sup.4, acids such as HC.sup.1,
H.sup.2SO.sup.4, and alkali like ammonia may be used, and any of
those described above may be selected according to the
characteristics of the workpiece. It is desirable, when using
electrolysis solution, to have a minimal clearance gap between the
wafer W and the ion exchanger 48 for preventing them from
contacting each other directly.
[0120] Further, in place of deionized water or ultrapure water, a
solution prepared by adding such a material as a surface active
agent to adjust the electric conductivity to a value less than 500
.mu.S/cm, preferably less than 50 .mu.S/cm, and more preferably
less than 0.1 .mu.S/cm (with the specific resistance of 10
M.OMEGA..multidot.cm or more) may be used. By using the solution
prepared by adding a surface active agent to the deionized water or
ultrapure water, it is possible to form a layer having the stable
inhibitory action for preventing ions from moving onto an interface
between the surface W and the ion exchanger 48., thereby improving
the flatness of the processed surface by moderating a concentration
of the ion exchange (dissolution of metal). The concentration of
the surface active agent should preferably be less than 100 ppm.
When the value of the conductivity is too high, the processing
speed becomes lower, but by using a solution with a conductivity of
less than 500 .mu.S/cm, preferably less than 50 .mu.S/cm and more
preferably less than 0.1 .mu.S/cm, the desired processing speed can
be achieved.
[0121] Further, with the present invention, the ion exchanger 48 is
placed between the wafer W and the processing electrode 44 and
between the substrate W and the feeding electrode 46 to
substantially improve the processing speed. In short, electrolytic
processing with ultrapure water is achieved by a chemical
interaction between hydroxide ions in the ultrapure water and the
material to be processed. As a concentration of hydroxide ions as
the reacting species contained in the ultrapure water is extremely
low: 10.sup.-7 mol/L at the normal temperature and pressure, the
efficiency in the processing for removal may be lowered due to
reactions other than that for the action for removal (such as
formation of an oxide film). In order to keep the removal reactions
at a high efficiency level, an increase in hydroxide ions is
required. To increase the hydroxide ions, there is a method in
which dissolution of water molecules in ultrapure water is promoted
by using a catalytic substance; one useful material available for
that purpose is an ion exchanger. Specifically, an amount of energy
required for activating dissolution of water molecules is lowered
as a result of interactions between the functional group in the ion
exchanger and water molecule. So the processing speed can be raised
by promoting dissolution of water.
[0122] In this process, if copper is electrolytically processed
using the ion exchanger 48 with a cation exchange group given
thereto, the copper is saturated with the ion exchange groups of
the ion exchanger (cation exchanger) 48, and in that case the
processing efficiency in the subsequent process is lowered.
Further, if copper is electrolytic processed using the ion
exchanger 48 with an anion exchange group assigned thereto, fine
particles of copper oxide are deposited on a surface of the ion
exchanger (anion exchanger) 48, and contamination may occur on a
surface of the substrate to be processed next.
[0123] To avoid the problems troubles described above, the
regenerating head 58 held at the free end of the oscillating arm 56
is moved to close with each other or directly contact with each
other the ion exchanger 48 on the processing table 42, and in that
state an electric potential reverse to that applied during the
processing is applied to the ion exchanger 48 from the power supply
unit 52, which promotes dissolution of extraneous matters such as
copper deposited on the ion exchanger 48, thus the ion exchanger 48
being regenerated during the processing. In this case, the
regenerated ion exchanger 48 is rinsed with the deionized or
ultrapure water supplied to the top surface of the processing table
42.
[0124] FIG. 4 shows a main section of the electrolytic processing
device according to another embodiment of the present invention,
and this section detects an end point of electrolytic processing by
detecting a change in the calorific value generated during the
processing between the processing electrode 44 and the feeding
electrode 46 by means of checking the change of temperature of the
substrate W. More specifically, a temperature sensor 430 for
directly detecting a surface of a rear surface of the substrate W
held by the top ring 74 is embedded in a lower edge surface of the
top ring 74, and a signal detected by the temperature sensor 430 is
sent to a signal processor 436 as a processing end point detecting
section through a telemeters 432, 434, and the signal processed by
this signal processor 436 is sent to the control section 438. Other
configuration is almost the same as those described above.
[0125] As the temperature sensor 430, for example, a thermistor or
a thermocouple is used, however, other types of sensor may also be
used. The substrate W such as a semiconductor wafer is generally
extremely thin and includes silicon as its main ingredient, so that
the thermal conductivity of the substrate W is very high. Because
of this feature, by monitoring the temperature at the rear surface
of the substrate W, a calorie value generated between processing
and feeding electrodes 44, 46 and the substrate W can be
detected.
[0126] In electrolytic processing, heat is generated not only by
the electrical resistance on a surface of the workpiece but also
because of collisions of ions and water molecules moving around in
the solution (deionized water) between the processing surface and
the processed, and for instance, when electrolytic polishing is
executed at a fixed voltage for polishing the copper coating 6
deposited on the surface of substrate W as shown in FIG. 22B, the
electric resistance becomes larger with the current becoming
smaller as the electric processing proceeds and the barrier layer 5
or the insulating film 2 is exposed, and the heat value and the
temperature of the substrate W held by the top ring 74 gradually
drops. Therefore, by detecting the heat value (temperature of the
substrate W) to determine the integrated processing rate, it is
possible to detect the processing end position.
[0127] In other words, in this example, the signal processor 436
determines that the barrier layer 5 comprising, for instance, TaN
or the like has been exposed on a surface of the substrate W and
judges that a processing end point has come when it detects, by
receiving a signal generated and detecting a temperature change
with the temperature sensor 430 and transmitted from the telemeters
432, 434 that a degree of change in the temperature has reached a
predetermined value. This signal processor 436 transmits, when it
detects the end point of processing, a signal indicating the end of
processing to the control section 438.
[0128] FIG. 6 shows a main portion of an electric processing
section according to another embodiment of the present invention,
and this portion detects an end point of the processing by
detecting a change in amplitude of the light introduced onto a
surface of the copper coating 6 and reflected on a surface of the
workpiece (copper coating 6) In other words, an optical sensor 440
having a recessed section 42a exposed upwards provided thereon and
equipped with a light emitting element and a light receiving
element in the recessed section is provided on the processing table
42. The signal detected by this optical sensor 440 is provided as
an input to the signal processor 442 which acts as a processing end
point detecting section, and the signal processed by the signal
processor 442 is input to the control section 444. Other portions
of the configuration are similar to those described above.
[0129] The optical sensor 440 emits light from the light emitting
element to a surface to be processed of the substrate W held by the
top ring 74, that is a surface of the copper coating 6 and receives
the light reflected on the processed surface (copper coating 6) by
means of the light receiving element. In this case, the light
emitted from the light emitting element is, for instance, a laser
beam or LED.
[0130] When the copper coating 6 deposited on a surface of the
substrate W shown in FIG. 22(b) is electrolytically polished
controlling the voltage at a constant level, as the electrolytic
processing proceeds and the barrier layer 5 and further the
insulating film 2 are exposed, the amplitude of the reflected light
changes due to the different of reflection indexes between the
barrier layer 5 and the insulating film 2. Therefore it is possible
to determine an integrated processing range by detecting the
amplitude of the reflected light to determine the processing end
point.
[0131] Briefly, in this case, when the signal processing apparatus
442 receives a signal detected by the optical sensor 440 and
determines, for instance, that the change in amplitude of the
reflected light has reached a predetermined value, it determines,
for instance, that the barrier layer 5 comprising such as material
of TaN has been exposed on a surface of the substrate W, and judges
that the processing end point has come. When the signal processor
442 determines the processing end point, it sends a signal
indicating the end of processing to the control section 444.
[0132] FIG. 7 shows a main portion of the electrolytic processing
device according to still another embodiment of this present
invention. This portion detects an end point of processing by
detecting a change in the eddy current generated during the
processing inside a workpiece, namely in the copper coating 6.
Namely an eddy current sensor 450 which generates an eddy current
inside a conductive film such as the copper coating 6 deposited on
a surface of the substrate W and detects the amplitude of the
generated eddy current is embedded in the processing table 42, and
the signal detected by this eddy current sensor 450 is input to a
signal processor 452 which acts as an processing end point
detecting section. The signal processed by the signal processor 452
is input to a control section 454. Other portions of the
configuration are similar to those described above.
[0133] The eddy current sensor 450 is equipped with a sensor coil.
By supplying a high-frequency current to the sensor coil, an eddy
current can be generated inside the conductive film such as the
copper coating 6 deposited on the surface of the substrate W and
the amplitude of the eddy current varies in proportion to the
thickness of the conductive film of copper coating 6.
[0134] For this reason, in this example, the eddy current sensor
450 detects the amplitude of the eddy current generated inside the
conductive film such as the copper coating 6 deposited on the
surface of the substrate W. The signal detected by this eddy
current sensor 450 is sent to the signal processor 452. When this
signal processor 452 detects, for instance, that a change in the
eddy current increased over a predetermined value, it determines
that the barrier layer 5 comprising TaN or the like has been
exposed, and detects the processing end point. When the signal
processor 452 detects the processing end point, it sends a signal
indicating the processing end point to the control section 454.
[0135] FIG. 8 shows a substrate processing apparatus 10A according
to a second embodiment of this present invention. Differences
between the substrate processing apparatus 10A and the substrate
processing apparatus 10 shown in the previous FIG. 1 and FIG. 2 are
that a fixed abrasive member 90 comprising a fixed abrasives is
adhered on a surface (top surface) of the polishing table 30 to use
a surface of this fixed abrasive member 90 as the polishing surface
90a so as to form the chemical-mechanical polishing section 24, and
that the polishing solution nozzle 92 for supplying deionized water
not containing any abrasive materials or a solution 91 prepared by
adding an additive such as a surface active agent to the deionized
water is provided at a position above the polishing table 30.
[0136] The fixed abrasive member is formed by mixing abrasive
particles such as ceria or silica in a binder such as a
thermosetting resin such as an epoxy resin, a thermoplastic resin,
or a core shell type of resin such as MBS or ABS and molding the
mixture with a die into a plate form. The ratio of the abrasive
particles: binder: void=10-50%:30-80%:0-40% (boundary values
included).
[0137] The fixed abrasive member 90 constitutes an extremely hard
polishing face 90a and prevents occurrences of scratches and
insures the stable processing speed. Further the fixed abrasive
member 90 executes the chemical-mechanical polishing by supplying
deionized water not containing any abrasive particles or the
solution prepared by adding an additive such as a surface active
agent to deionized water, so that it enables reduction of a usage
of a polishing solution which is expensive and hard to treat.
[0138] FIG. 9 shows a substrate processing apparatus 10b) according
to a third embodiment of the present invention. The differences
between this substrate processing apparatus 10b and the substrate
processing shown in FIG. 1 and FIG. 2 are that the polishing table
30 has a diameter slightly larger than that of a substrate W and
performs an orbital motion not associating rotation of itself,
namely s so-called translational movement (scroll movement) in
accordance with rotation of the hollow motor 94; and that an
abrasive solution is supplied to the polishing pad 32 through a
hollow section of the hollow motor 94 and an abrasive solution path
30a provided inside the polishing table 30 when a pump 98 installed
in an abrasive solution feed line 96 runs. In this example, it is
possible to reduce a size of the polishing table 30 and also to
keep the sliding speed between the substrate W and a polishing
surface 32a of the polishing pad 32 at a constant level over the
entire surface of the substrate W.
[0139] FIG. 10 shows a substrate processing apparatus 10c according
to a fourth embodiment of the present invention. The differences
between this substrate processing apparatus 10c and the substrate
processing apparatus 10 shown in FIG. 1 and FIG. 2 are that as the
chemical-mechanical polishing section 24, an endless type of
polishing pad is spanned over a drive roller 100 driven by a motor
and a driven roller 102 located in parallel to the drive roller 100
so that it can run freely and a pressing base 106 is placed under
the polishing cloth 104 running above; and that a three-layered
laminated body consisting of a pair of strongly acidic cation
exchange textile 48a, 48b and a strongly acidic cation exchange
film 48c held between these strongly acidic cation exchange textile
48a, 48b is used as the ion exchanger 48 placed on a top surface of
the processing table 42 of the electrolytic processing section 26.
The abrasive solution nozzle 36 for supplying the abrasive solution
34 is placed in the upstream side from the pressing base 106. The
ion exchanger (laminated body) 48 have high water-permeability, and
not only the solidity is very high, but also an exposed surface
(top surface) opposing the substrate W has excellent
smoothness.
[0140] In this example, the substrate W held via the cylinder 78 by
the top ring 74 is pressed to a polishing surface of the polishing
pad 104 with a predetermined pressing force and the polishing pad
104 runs while the top ring 74 is rotated, and at the same time the
abrasive solution 0.34 is supplied from the abrasive solution
nozzle 36 to the polishing cloth 104, thus a top surface
(undersurface) of the substrate W being chemically-mechanically
polished.
[0141] Since the ion exchanger 48 is formed to be as a
multi-layered structure by overlaying a plurality of sheets of ion
exchange materials such as non-woven cloth, woven cloth, or porous
films, the total ion exchange capacity of the ion exchanger 48 can
be increased, and thereby negative influences of oxides over the
processing rate can be prevented by suppressing generation of
oxides upon processing (polishing) copper for removal. Namely, when
the total ion exchange rate by the ion exchange 48 is smaller than
a quantity of copper ions fetched during the removing process,
oxides are generated on a surface of or inside the ion exchanger,
which gives negative effects over the processing rate. It is
assumed that this phenomenon occurs because a quantity of ion
exchange groups in the ion exchanger affects the processing rate
and copper ions over the required capacity are converted to oxides.
To overcome this problem, generation of oxides can be suppressed by
making larger a total ion exchange rate by using an ion exchanger
based on a multilayered structure consisting of a plurality of
sheets of ion exchange material.
[0142] FIG. 11 shows a substrate processing apparatus 10d according
to a fifth embodiment of the present invention. This substrate
processing apparatus 10d has the chemical-mechanical polishing
section 24 and the electrolytic processing section 26 similar to
those used in the substrate processing apparatus 10 shown in FIG. 1
and FIG. 2, and a pusher 108 having a load/unload mechanism is
provided between this chemical-mechanical polishing section 24 and
the electrolytic processing section 26.
[0143] Further, disposed at the side of the chemical-mechanical
polishing section 24 is a first pivot 110 which is freely
pivotable, and a first top ring head 112 which is oscillatable in
accordance with a pivotal movement of the pivot 112 is mounted on
the pivot 112 so that it can freely move in the vertical direction.
A first elevating shaft 114 is rotatably supported at a free end of
this first top ring head 112, and a first top ring 116 for
releasably holding a substrate W is attached to a lower edge of
this first elevating shaft 114. Further a cylinder 118 for pressing
the substrate W held by this first top ring 116 against a polishing
surface 32a of the polishing table 30 with a predetermined force,
and a motor 120 for rotating the first top ring are provided
therein.
[0144] With the configuration as described above, it is possible to
suck and hold a substrate W placed on the pusher 108 by means of
the first top ring moved to a position directly above the pusher
108 by causing pivotal movement of the first pivot 110, to move the
substrate W held by this first top ring 116 to a position above the
polishing table 30 by causing pivotal movement of the first pivot
110, to perform chemical-mechanical polishing of a surface of the
substrate W at this position, and to move the polished substrate W
to a position just above the pusher 108 by causing pivotal movement
of the first pivot 110 and return it to the pusher 108.
[0145] On the other hand, disposed at the side of the electrolytic
processing section 26 is a second pivot 130 which is freely
pivotable, and a second top ring head 132 oscillating in accordance
with pivotal movement of the pivot 130 is disposed on this second
pivot 130 so that it can move freely in the vertical direction. A
second elevating shaft 134 is rotatably supported at a free edge of
this second top ring head 132, and a second top ring 136 for
releasably holding the substrate W is attached to a lower edge of
this second elevating shaft 134. Further, a motor 140 for rotating
the second top ring 136 is provided therein.
[0146] With this configuration, it is possible to suck and hold the
substrate W placed on the pusher 108 by means of the second top
ring 136 moved to a position just above the pusher 108 by causing
pivotal movement of the second pivot 130, to move the substrate W
held by this second top ring 136 to a position above the processing
table 42 by causing pivotal movement of the second pivot 130 and
electrolyticaly process a surface of the substrate W at this
position, and to move the substrate W having been subjected to
electrolytic processing to a position just above the pusher 108 by
causing pivotal movement of the second pivot 130 and return it onto
the pusher 108.
[0147] In this example, it is possible to place a substrate
polished, for instance, by the chemical-mechanical polishing
section 24 on the pusher 108, and also to electrolytically machine
the polished substrate W placed on the pusher 108 in the
electrolytic processing section and then return it to the pusher
108, and thus the two types of processing, namely the
chemical-mechanical polishing in the chemical-mechanical polishing
section 24 and electrolytic processing (etching) in the
electrolytic processing section 26 can sequentially be carried
out.
[0148] FIG. 12 and FIG. 13 shows a substrate processing apparatus
10e according to a sixth embodiment of the present invention. This
substrate processing apparatus 10e has the two chemical-mechanical
polishing sections 24a, 24b and one electrolytic processing section
26, all of which are similar to those in the substrate processing
apparatus 10 shown in FIG. 1 and FIG. 2. The chemical-mechanical
polishing sections 24a, 24b and the electrolytic processing section
26 are provided at positions along a straight line, and a substrate
carrier device 150 which runs holding the substrate W is provided
at the side thereof.
[0149] This substrate carrier device 150 has a base 152 and a
running section 156 which has the configuration similar to the
carrier section 28 of the substrate processing apparatus 10 shown
in FIG. 1 and FIG. 2 and capable of running along the base 152 when
driven by the running motor 154 provided in the base 152. This
running section 156 has a support 158, and a elevating plate 162
which moves up and down in the axial direction when driven by a
motor 160 attached to an upper end of the support 158 is provided
on this support 158, and a base end section of the top ring head
164 extending in the horizontal direction is fixed to this
elevating plate 162. An elevating shaft 166 is provided at a free
end of this top ring head 164, and a top ring 168 releasably
holding a substrate W is provided at a lower end of this elevating
shaft 166 via a ball joint 170 so that it can freely incline.
[0150] Disposed in parallel to the elevating shaft 166 is a
cylinder 172 for pressing the substrate W held by the top ring 168
via the elevating shaft 166 with a predetermined pressing force to
the polishing surface 32a of the polishing table 30. Further a
timing belt 180 connects the driven pulley 174 attached to this
elevating shaft 166 with the drive pulley 178 attached to the drive
shaft of the motor 176 for rotating the top ring, and because of
this configuration, the top ring 168 rotates monolithically with
the elevating shaft 166.
[0151] With this configuration, for instance, when it is required
to carry out in order chemical-mechanical polishing first in one of
the chemical-mechanical polishing sections 24a, then electrolytic
processing in the electrolytic processing section 26, and finally
again chemical-mechanical polishing in the other
chemical-mechanical polishing section 24b, in the state where the
substrate W is held by the top ring 168, the top ring 168 is moved
to a position above the polishing table 30 of the
chemical-mechanical polishing section 24a by making the running
section 156 run. Then., the top ring 168 is caused to descend and
the polishing table 30 and the top ring 168 are rotated in a state
where the substrate W held by the top ring 168 via the cylinder 172
is pressed with a predetermined pressing force against the
polishing surface 32a of the polishing table 30, and concurrently
an abrasive solution is supplied from the abrasive solution nozzle
36 to the polishing pad 32. By these operations, a top surface (or
undersurface) of the substrate W is subjected to the
chemical-mechanical polishing.
[0152] Then, in a state where the substrate W is held by the top
ring 168, the top ring 168 is moved upward and the running section
156 run to move the top ring 168 to a position above the processing
table 42 of the electrolytic processing section 26. The motor 160
rotates to move the substrate W held by the top ring 168 to a
position close to or directly contacting the ion exchanger 48 on
the processing table 42, and in this state the processing table 42
and the top ring 168 are rotated, and at the same time a voltage is
applied between the processing electrode 44 and the feeding
electrode 46 while supplying deionized water or preferably
ultrapure water to the ion exchanger 48 on the processing table 42.
With this operation, a top surface (undersurface) of the substrate
is electromechanically processed (etched).
[0153] Then in the state where the substrate W is held by the top
ring 168, the top ring 168 is moved upward with the running section
156 run to move the top ring 168 to a position above the polishing
table 30 of the chemical-mechanical polishing section 24b. Then, as
described above, the polishing table 30 and the top ring 168 are
rotated pressing with a predetermined force the substrate W held
via the cylinder 172 by the top ring 168 against the polishing
surface 32a of the processing table 30, and concurrently an
abrasive solution is supplied from the abrasive solution nozzle 36
to the polishing pad 32 to chemically-mechanically polish a surface
(undersurface) of the substrate.
[0154] In each of the chemical-mechanical polishing sections 24a,
24b, chemical-mechanical polishing is carried out with the
processing steps being changed. Changing a process step means
changing at least one of processing tools, the relative speed
between a substrate and a polishing surface, a processing solution,
and a pressing force against the substrate or the like. It is to be
understood herein that the chemical-mechanical polishing may be
carried out with different process steps in the same
chemical-mechanical polishing section.
[0155] FIG. 14 shows a substrate processing apparatus 10f according
to a seventh embodiment of the present invention. This substrate
processing apparatus 10f has two chemical-mechanical polishing
sections 24a, 24b and a electrolytic processing section 26, all of
which have a configuration similar to those in the substrate
processing apparatus 10 shown in FIG. 1 and FIG. 2. Pushers 108a,
108b each having a load/unload mechanism which has a configuration
similar to that provided in the substrate processing apparatus 10d
shown in FIG. 11 are provided between the chemical-mechanical
polishing section 24a and the electrolytic processing 26 and
between the two chemical-mechanical polishing sections 24a, 24b,
respectively.
[0156] Further provided at the side of each of the
chemical-mechanical polishing sections 24a, 24b is a first pivot
110 which is freely pivotable and has a configuration similar to
that of the first pivot 110 provided in the substrate processing
apparatus 10d shown in FIG. 11. With this configuration it is
possible to suck and hold a substrate W placed on the pusher 108a
or pusher 108b by the first top ring 116 having been moved to a
position just above the pusher 108a or 108b by causing pivotal
movement of the first pivot 110, to move the substrate W held by
this top ring 116 to a position above the processing table 30 by
causing pivotal movement of the first pivot 110 and carrying out
chemical-mechanical polishing on a surface of the substrate W at
this position, and to move the polished substrate W to a position
just above the pusher 108a or 108b by causing pivotal movement of
the first pivot 110 and return it to the pusher 108a or 108b.
[0157] On the other hand, disposed at the side of the electrolytic
processing section 26 is a second pivot 130 having a configuration
similar to that in the substrate processing apparatus 10d shown in
FIG. 11. With this configuration it is possible to suck and hold
the substrate W placed on the pusher 108a with the second top ring
136 having been moved to a position just above the pusher 108a by
causing pivotal movement of the second pivot 130, to move the
substrate W held by this second top ring 136 to a position above
the processing table 42 by causing pivotal movement of the second
pivot 130 and carrying electrolytic processing (etching) to a
surface of the substrate W at the position, and then to move the
electrolytically processed substrate W to a position just above the
pusher 108a by moving the second pivot 130 upward and return it to
the pusher 108a.
[0158] In this example, for instance, a substrate having been
subjected to electrolytic processing in the electrolytic processing
section 26 is placed on the pusher 108a; the substrate having been
subjected to electrolytic processing and placed on the pusher 108a
is polished in the chemical-mechanical polishing section 24a; then
the polished substrate is placed on the pusher 108b; and then the
polished substrate placed on the pusher 108b is polished in the
chemical-mechanical polishing section 24b and returned to the
pusher 108b. With this configuration, by delivering the substrate W
via the pushers 108a and 108a, the chemical-mechanical polishing in
the chemical-mechanical polishing sections 24a, 24b and
electrolytic processing (etching) in the electrolytic processing
section 26 can be carried out sequentially.
[0159] In this example, two pushers 108a, 108b each having a
load/unload mechanism are provided, however, for example, a
configuration in which a pusher having a load/unload mechanism is
provided only between the chemical-mechanical polishing section 24a
and the electrolytic processing section 26 and an ordinary top ring
is provided between the two chemical-mechanical polishing sections
may be used.
[0160] FIG. 15 and FIG. 16 show a substrate processing apparatus
10g according to an eighth embodiment of the present invention, and
FIG. 17 shows the entire configuration of the substrate processing
system having this substrate processing apparatus 10g. As shown in
FIG. 17, this substrate processing system comprises a pair of
load/unload sections 12 as a carry in/out section for carrying into
or out from a cassette accommodating therein a substrate W having,
for example, the copper coating 6 (shown in FIG. 22(b)) as a
conduction film (a section to be processed) on a surface thereof, a
reversing machine 14 for reversing the substrate W, a pusher 16 for
receiving or delivering the substrate, a cleaning device 18, and a
substrate processing apparatus 10g. Further disposed at a position
surrounded by the load/unload section 12, reversing machine 14,
pusher 16, and cleaning device 18 is a carrier robot 20 of a
running type as a carrier for carrying the substrate W for
transferring between the components. Further a control section 22
is provided. This control section 22 performs various types of
controls such as those over a voltage applied to between the
processing electrode 44 and the feeding electrode 46, or a current
flowing between the two electrodes.
[0161] A plurality of electrolytic processing sections are provided
in the substrate processing apparatus log. For instance, in the
examples shown in FIG. 15 and FIG. 16, two electrolytic processing
sections, namely a first electrolytic processing section 26a and a
second electrolytic processing section 26b each for etching a
surface of a substrate by means of electrolytic processing with
ultrapure water or deionized water are provided, and a carrier
section 28 for releasably holding a substrate W and carrying it
between the first electrolytic processing section 26a and the
second electrolytic processing section 26b is disposed
therebetween.
[0162] The first electrolytic processing section 26a and the second
electrolytic processing section 26b each have the processing table
42 which is connected to the hollow motor 40 and performs an
orbital motion not associating with rotation of itself, namely the
so-called translational movement (scroll movement) in accordance
with rotation of the hollow motor 40. This processing table 42
comprises an insulating body, and processing electrodes 44 and
feeding electrodes 46 each having a fan-shaped form are embedded on
a top surface of this processing table 42 with a predetermined
space along the periphery thereof. First ion exchangers 48d are
mounted on the processing electrodes 44 and the feeding electrodes
46 in the first electrolytic processing section 26a respectively,
while second ion exchangers 48e are mounted on the processing
electrodes 44 and feeding electrodes 46 in the second electrolytic
processing section 26b respectively.
[0163] The first ion exchangers 48d used in the first electrolytic
processing section 26a have high elasticity and are hard to deform,
while the second ion exchangers 48e used in the second electrolytic
processing section 26b had lower elasticity (or a lower elastic
modulus and easier to deform as compared to the first ion
exchangers 48d) respectively. The ion exchanger 48d having the high
elasticity is, for instance, Nafion 117 (produced by DuPont Corp.).
The ion exchanger 48e with low elasticity is, for instance, woven
cloth or non-woven cloth graft-polymerized and having the ion
exchange capability.
[0164] Needless to say that the ion exchangers having any form or
structure including the three-layered structure used in the
substrate processing apparatus 10c shown in FIG. 10 may be used for
the ion exchangers 48d, 48e.
[0165] Further the first electrolytic processing section 26a is
different from the second electrolytic processing section 26b only
in that the types of ion exchangers used in the respective
electrolytic processing sections are different (in the term of
elasticity) from each other, and other portions of the
configuration are identical. Therefore the expression of ion
exchanger 48 is used for both the ion exchanger 48d in the first
electrolytic processing section 26a and the ion exchanger 48e in
the second electrolytic processing section 26b.
[0166] Provided inside the hollow motor 40 is a deionized water
supply tube extending thereinto from the outside (not shown), and a
throughhole opened on a top surface of the processing table 42
communicating to the deionized supply tube is provided at the
center of the processing table 42. With this configuration, the
deionized water, or preferably ultrapure water is supplied through
this deionized supply tube and the throughhole to the ion
exchangers 48 on the top surface of the processing table 42.
[0167] Further as shown in FIG. 15, provided at the side of the
processing table 42 is a regenerating section 54 for regenerating
the ion exchanger 48. This regenerating section 54 comprises an
oscillating arm 56 capably of freely oscillating and a regeneration
head 58 held at a free end of this oscillating arm 56, and can
regenerate the ion exchanger 48 even during processing by applying
a voltage reverse to that applied during the processing to the ion
exchanger 48 to promote dissolution of deposits such as copper
deposited on the ion exchanger 48. The regenerated ion exchanger 48
is rinsed with deionized water or ultrapure water supplied onto a
top surface of the processing table 42.
[0168] The carrier section 28 has a pivot 62 which pivots when it
is driven by a motor attached to a lower end thereof and positioned
between the electrolytic processing section 26a and the second
electrolytic electrode. This pivot 62 has a elevating plate 66
which moves up and down when driven by the elevating motor 64
attached to an upper end thereof, and a base edge section of the
top ring head 68 extending in the horizontal direction is fixed to
this elevating plate 66. An elevating section 72 is provided at a
free edge of this top ring head 68, and a top ring 74 for
releasably holding a substrate W is jointed thereto via a ball
joint 76 in the manner allowing the top ring 74 to freely
incline.
[0169] In parallel to the elevating shaft 72, a cylinder 78 for
moving up and down the elevating shaft 72 is provided. A timing
belt 86 connects the section between the driven pulley 80 attached
to this elevating shaft 72 with a drive pulley 84 attached to a
pivot of this motor 82 for rotating the top ring, and when driven
by the motor 82, the top ring 74 rotates monolithically with the
elevating shaft 72.
[0170] With this configuration, the top ring head 68 is oscillated
to move the top ring 74 to a position directly above the pusher 16
shown in FIG. 17, and then pusher 16 is moved upward so that the
top ring head 68 can receive the substrate W. Then in the state
where the top ring 74 holds the substrate W, the top ring head 68
is oscillated to mount the top ring 74 on the processing table 42
in either the first electrolytic processing section 26a or the
second electrolytic processing section 26b. The top ring 74 is
descended to move the substrate W to a position close to or
contacting the ion exchanger 48 on the processing table 42, and in
this state, the processing table 42 and the top ring 74 are
rotated, and a voltage is applied between the processing electrode
44 and the feeding electrode 46 supplying deionized water or
ultrapure water to the ion exchangers 48 on a top surface of the
processing table 42. With this operation, a top surface
(undersurface) of the substrate W is electrolytically processed
(etched).
[0171] Next the substrate processing (electrolytic processing) with
this substrate processing system is described below. At first, one
substrate W is taken out by means of a carrier robot 20 from a
cassette accommodating therein substrates W having copper coating 6
formed as a conductive film (a processed section) on a surface
thereof and set in the load/unload section 12, and the substrate W
is carried to and reversed on the reversing machine, if required,
to position the substrate W so that the surface with the copper
coating 6 formed thereon faces downward. Then the substrate turned
upside down is carried by the carrier robot 20 to the pusher 16 and
is placed on the pusher 16. Then the top ring head is oscillated to
move the top ring 74 to a position just above the pusher 16, and
then the pusher 16 is raised to such and hold the substrate W on
the pusher 61 with the top ring 74.
[0172] Thereafter, in the state where the substrate W is held by
the top ring 74, the top ring head 68 is oscillated to move the top
ring 74 to a position above the processing table 42 in the first
electrolytic processing section 26a. Then the top ring 74 is
descended, and the substrate W held by the top ring 74 is moved to
a position close to or contacting the ion exchanger 48d on the
processing table 42. In this state, the processing table 42 and the
top ring 74 are rotated, and concurrently a voltage is applied
between the processing electrode 44 and the feeding electrode 46
supplying deionized water or preferably ultrapure water to the ion
exchangers 48e on a top surface of the processing table 42, thus a
top surface (undersurface) of the substrate is electrolytically
processed.
[0173] In the first electrolytic processing section 26a, polishing
is carried out by using an ion exchanger 48 with a smooth surface
and high elasticity to eliminate steps generated on a surface of
the copper coating 6 laminated on the substrate W. Namely, if the
ion exchanger is soft and easily deforms, the ion exchanger easily
follows irregularities on the surface of the copper coating 6, and
if that case it is difficult to selectively eliminate convex
sections on the surface. When an ion exchanger with a smooth
surface and high elasticity (is hard to deform) is used, the
processing proceeds only in the sections contacted by the copper
coating 6, so that steps thereof are eliminated.
[0174] When polishing of the copper film 6 proceeds on the
substrate W and it is determined that steps have been eliminated,
the power is disconnected with the top ring 74 raised, and rotation
of the processing table 42 and top ring 74 is stopped.
[0175] Then in the state where the substrate W is holed by the top
ring 74, the top ring 68 is oscillated to move the top ring 74 to a
position above the processing table 42 in the second electrolytic
processing section 26b. Then the top ring 74 is descended, and the
substrate W held by the top ring 74 is moved to a position close to
or contacting the ion exchanger 48e on the processing table 42, and
in this state, the processing table 42 and the top ring 74 are
rotated with deionized or ultrapure water being supplied to ion
exchangers 48e on a top surface of the processing table 42, and in
this state a voltage is applied between the processing electrode 44
and feeding electrode 46 to electrolytically machine a top surface
(undersurface) of the substrate.
[0176] In the second electrolytic processing section 26b, polishing
of the copper coating 6 is performed by using the ion exchanger 48e
with a smooth surface and low elasticity. Namely it is necessary to
execute processing for removing the copper coating 6 down to a
predetermined film thickness even after the steps have been
eliminated, and in that case, as a surface of the copper film 6 is
flat, an ion exchanger with high elasticity is not required. For
this reason, for processing the copper coating 6 after the steps
have been eliminated, an ion exchanger with low elasticity may be
used. As polishing of the substrate W proceeds on the substrate W
and it is detected that the barrier metal (barrier layer) 5
comprising material such as TaN has been exposed, the power 52 is
disconnected with the top ring 74 raised, and rotation of the
processing table 42 and top ring 74 is stopped.
[0177] It is not necessary to change such factors as the relative
speed when processing is performed in the first electrolytic
processing section 26a and the second electrolytic processing
section 26b. However, the lower current density is better for
effectively eliminating the steps. Therefore, the current density
is preferably set to a relatively lower level when processing for
flattening is performed in the first electrolytic processing
section 26a, while the current density is preferably set to a
relatively higher level for processing in the second electrolytic
processing section 26b after flattening to remove steps on the
entire surface of the substrate at a high speed. Further for
processing in the first electrolytic processing section 26a, it is
preferable to use ultrapure water as a solution to be supplied for
flattening, but for processing in the second electrolytic
processing section 26b, since the surface has already been made
flat, a solution containing electrolytes may be used as a
processing solution for performing processing at a high speed. In
that case, it is not necessary to position an ion exchanger in the
second electrolytic processing section 26b. Further, when the film
thickness is larger as compared to the steps, processing with an
electrolytic solution may be performed at first in the second
electrolytic processing section 26b and then processing with
ultrapure water in the first electrolytic processing section
26a.
[0178] After the polishing is finished, the top ring head 68 is
oscillated to deliver the substrate W to the pusher 16. The carrier
robot 20 receives the substrate W from this pusher 16, carries the
substrate W to the reversing machine 14 to reverse the substrate.
The carrier robot further carries the substrate W to the cleaning
device 18, and then returns the cleaned substrate W to the
load/unload section 12.
[0179] FIG. 18 shows a substrate processing apparatus 10h according
to a ninth embodiment of the present invention. This substrate
processing apparatus 10h has, in addition to a first electrolytic
processing section 26a and a second electrolytic processing section
having the configuration similar to those in the substrate
processing apparatus log shown in FIG. 15 and FIG. 16, a third
electrolytic processing section 26c, and pushers 208, 208 each
having a load/unload mechanism are provided between the first
electrolytic processing section 26a and the second electrolytic
processing section 26b, and between the second electrolytic
processing 26b and the third electrolytic processing 26c. This
third electrolytic processing section 26c uses, as the third ion
exchanger 48f, an ion exchanger which is best suited for polishing
and removing the barrier metal (barrier layer) 5 as shown in FIG.
22(a). The other portions of the configuration are similar to those
of the first electrolytic processing section 26a and the second
electrolytic processing section 26b.
[0180] Provided at the side of each of the first electrolytic
processing section 26a, second electrolytic processing section 26b,
and third electrolytic processing section 26c is a pivot 210 which
is freely pivotable. With this configuration, the substrate W
placed on the pusher 208a or 208b is sucked and held by the top
ring 216 moved to a position just above the pusher 208a or 208b by
swiveling an arm 212 via the pivot 210, and the substrate W held by
the top ring 216 is moved to a position above the processing table
42 by swiveling the pivot 210, and is subjected to electrolytic
processing (etching) at the position, and further the substrate W
having been subjected to this electrolytic processing is moved to a
position just above the pusher 208a or 208b by swiveling the pivot
210 to return it to the pusher 208a or 208b.
[0181] In this case, as described above, the substrate W having
been polished so that the barrier metal 5 comprising, for instance,
TaN is exposed is placed on the pusher 208b, and then this
substrate W is carried to the third electrolytic processing section
26c, and the barrier metal 5 is polished and removed in this third
electrolytic processing section from the substrate W. When it is
detected that a surface of the copper coating 6 filled in the
groove 4 for wiring, as well as in the contact hole 3, and a
surface of the insulating film 2 is almost on the same plane, and
that the wiring comprising a copper line has been formed as shown
in FIG. 22(c), it is determined that polishing is finished. Then
the polished substrate W is returned to the cassette in the
load/unload section 12 via the pushers 208, 208b or the like in the
same way as described above.
[0182] With this configuration, processing, for instance, for
removal of barrier metal 6 can efficiently be executed under
different conditions in the third electrolytic processing section
26c using the ion exchanger 48f different from both the first ion
exchanger 48d and the second ion exchanger 48e.
[0183] Although, in this example, the barrier metal 5 is polished
and removed in the third electrolytic processing section 26c, a
chemical-mechanical polishing section for chemically and
mechanically polishing a substrate may be provided in place of this
third electrolytic processing section 26c for processing and
removing the barrier metal by means of chemical-mechanical
polishing (CMP) using a polishing pad and slurry in this
chemical-mechanical polishing section.
[0184] FIG. 19 shows a electrolytic processing section 300 in a
substrate processing apparatus 10i according to a tenth embodiment
of the present invention; FIGS. 20(a) and FIG. 20(b) show the state
where an ion exchanger holding section 204 holding an ion exchanger
302 thereon is set on an electrode section 318 of an electrolytic
processing section 318; and FIG. 21 shows the general configuration
of a substrate processing system having this substrate processing
apparatus 10i therein. This substrate processing apparatus 10i
comprises, as shown in FIG. 21, an electrolytic processing section
300; stockers 306a, 306b for accommodating a plurality of ion
exchanger holding members 304a, 304b of a cartridge type each
having, for instance a cartridge form and holding a film-formed ion
exchanger therein; and carrier robots 308, 309 each as a ion
exchanger holding section exchange means for exchanging the ion
exchanger holding members 304a,304b provided in the electrolytic
processing section 300 with the ion exchanger holding members 304a,
304b stored in the stockers 306a, 306b. Other portions of the
configuration of the substrate processing system are similar to
those shown in FIG. 17, so that the same reference numerals are
assigned to the same or corresponding members as those shown in
FIG. 17 and detailed description thereof is omitted herefrom. The
robots 308, 309 swivel on the pivots 308b, 309b respectively, and
the ion exchanger holding members 304a, 304b are reciprocally moved
between the stokers 306a, 306b and the electrolytic processing
section 300 with the arms 308a, 309a respectively.
[0185] The electrolytic processing section 300 comprises a
substrate holding section 312 provided under the free end of the
oscillating arm 310 capable of freely oscillate in the horizontal
direction for holding the substrate in the face-down position, and
an electrode section 318 having a disk-shaped form and comprising
an insulating body with processing electrodes 314 and feeding
electrodes 316 embedded thereon so that the top surfaces of the
processing electrodes 314 and feeding electrodes 316 are
alternately exposed on the same plane at upper and lower positions
respectively. The ion exchanger holding section 304 for holding the
ion exchanger 302 is releasably provided in the upper section of
the electrode section 318, and when this ion exchanger holding
section 304 is mounted in the upper section of the electrode
section 318, the ion exchanger 302 covers the surfaces of the
processing electrodes 314 and feeding electrodes 316.
[0186] In this example, an electrode section 318 having a diameter
slightly larger than that of the substrate W held on the substrate
holding section 312 is used as the electrode section 318 having the
processing electrodes 314 and the feeding electrodes 316 thereon,
and the electrode section 318 is relatively moved (scrolled) so
that the entire surface of the substrate W can simultaneously be
electrolytically processed.
[0187] The oscillating arm 310 for oscillating the substrate
holding section 312 is jointed to an upper edge of the oscillating
shaft 326 moving up and down via a ball screw 322 in accordance
with the drive of the motor 320 and also rotating in accordance
with the drive of the motor 344 for oscillating movement. Further
the substrate holding section 312 is connected to the motor for
rotation attached to a free edge of the oscillating arm 310, and is
rotated by a drive motor 328.
[0188] The electrode section 318 is directly connected to a hollow
motor 330 and is adapted to performs a scroll-type movement
(translational movement) under a driving operation of the hollow
motor. Provided in the central portion of the electrode section 318
is a through hole 318a which acts as a deionized water supply
portion for supplying deionized water, preferably, ultrapure water.
The through hole 318a is in fluid communication with deionized
water supply tube 334 extending through the inside of a hollow
portion of the hollow motor 330, through a through hole 332a formed
in a crank shaft 332 which is directly connected to a drive shaft
of the hollow motor 330 which operates to cause the scroll-type
movement of the electrode section. The deionixed water or ultrapure
water is supplied through the through hole 332a and then is
supplied to the entire workpiece surface through the water
absorptive ion exchanger 302.
[0189] The ion exchanger 302 is held by an ion exchanger holding
portion 304 having a pair of separate fixing members 340a, 340b
made of a ring-shaped insulator. The ion exchanger is adapted to be
fixed to and contacts an exposed surfaces of the process electrode
314 and the feeding electrode 316 in the condition that it extends
evenly over the entire surface thereof (under predetermined
tension). Namely, as shown in detail in FIG. 20(a) and FIG. 20(b),
the electrode section 318 includes a base portion 318b having a
large diameter and an electrode supporting portion 318c integrally
connected to the upper surface of the base portion, and having a
circular cylindrical shape with a small diameter. The ion exchanger
302 is temporarily fixed to the electrode supporting portion 304
with the peripheral portion thereof being clamped by the pair of
separate fixing members 340a, 340b and fixed by means of bolts and
the like, and then is held by the electrode supporting portion 304.
Under such a condition, the ion exchanger 302 is fixed by fitting
the ion exchanger holding portion 204 holding the ion exchanger to
the electrode supporting portion 318c to fix the ion exchanger
holding portion 304 to the electrode supporting portion 318c,
whereby the ion exchanger is fixed to the electrode supporting
portion.
[0190] Thus, when the ion exchanger holding portion 304 is fitted
to the electrode supporting portion, slippage is prevented from
occurring between the ion exchanger 302 and the ion exchanger
holding portion 304. The ion exchanger is thus fixed to the
electrode supporting section, while a predetermined tension is
applied to the ion exchange. The ion exchanger is formed to have a
multi-layer structure by stacking a plurality of like ion
exchanging layers, or a plurality of different ion exchanging
layers, on the other.
[0191] In this example, the robot 308 for exchanging has a pair of
arms 308a capable of being freely opened or closed, and the arms
308a holds the ion exchanger holding section 304 holding the ion
exchanger. With this configuration, the ion exchanger holding
section 304 mounted in electrode section can be exchanged with the
ion exchanger holding section 304 accommodated in the stocker 306.
Namely the robot 308 for exchanging is moved to a position where
the arms 308a surround the ion exchanger holding section 304 set on
the electrode section 318, and in this state, the arms 308a hold
the ion exchanger holding section 304 from both sides thereof. Then
the arms 308a are moved upward to pull off the ion exchanger
holding section 304 from an electrode support section 318c of the
electrode section 318, and then carry to the ion exchanger holding
section 304 into the stocker 306. In this state the arms 308 are
separated from each other to accommodate the ion exchanger holding
section 304 in the stocker 306.
[0192] Then the arms 308a of the robot 308 for exchanging are moved
to a position where the arms 308a surround the ion exchange holding
section 304 accommodated in the stocker to be exchanged, and in
this state the arms 308a are closed with each other and hold the
ion exchanger 304 in the stocker 306 from both sides thereof. Then
this ion exchanger holding section 304 are carried to a position
above the electrode support section 318c of the electrode section
318, and the arms 308a are descended to push the ion exchanger
holding section 304 into the electrode support section 318c of the
electrode section 318 for engaging it therein to fix the ion
exchanger holding section 304 in the electrode support section
318c, thus the ion exchanger 302 being fixed. Then the arms 308a
are separated from each other to release the ion exchanger holding
section and return the robot 308 for exchanging to the original
position.
[0193] In this example, by exchanging the ion exchanger 302 used
for processing in the electrolytic processing section 300, for
instance, via the cartridge type of ion exchanger holding section
304 for holding the ion exchanger 302 with another one, a plurality
of types of electrolytic processing can be performed with a
plurality of ion exchangers having different characteristics
respectively under different conditions in a single electrolytic
processing section 300.
[0194] The example of exchanging the ion exchanger with a robot was
described above, but the ion exchanger may be exchanged with
another one by an operator. In that case, the mechanism for
dismountably fixing the ion exchanger holding members 304a, 304b on
the electrode section 318.
[0195] In this example, the substrate W is sucked and held by the
substrate holding section 312 in the electrolytic processing
section 300 in the way similar to those described above, and the
substrate holding section 312 is moved to the processing position
just above the electrode section 318 by oscillating the oscillating
arm 310. Then the motor 320 is driven to descend the substrate
holding section 312, and the substrate W held by the substrate
holding section 312 is contacted to or moved to a position close to
a surface of the ion exchanger 302 placed on a top surface of the
electrode section 318 via the ion exchanger holding section 304. In
this state, a predetermined voltage is applied from the power
supply unit 336 to between the processing electrode 314 and the
feeding electrode 316 concurrently supplying deionized water or
ultrapure water to a top surface of the electrode section 318 from
the under side of the electrode section 318, and at the same time
the substrate holding section 312 is rotated with the electrode
section 318 scrolled, thus electrolytic processing being
performed.
[0196] In this step, the ion exchanger holding section 304 holding
the ion exchanger 302 suited to the electrolytic processing is
selected, and this ion exchanger holding section 304 is mounted on
this electrode section 318. With this operation, electrolytic
processing is performed by a desired ion exchanger. Namely the ion
exchanger 302 is exchanged with a desired one in conformity with
the processing condition of electrolytic processing via the ion
exchanger holding section 304, and thus a plurality of types of
electrolytic processing can be carried out in a single electrolytic
processing section by selectively using an ion exchanger suited to
given processing conditions.
[0197] As descried above, according to the present invention, when
electrolytic processing is carried out by applying a voltage
between a processing electrode, a feeding electrode, and a
workpiece, a processing end point for electrolytic processing can
surely be detected with a relatively simple configuration.
[0198] Further with the present invention, by employing
electrolytic processing using deionized water or ultrapure water
concurrently with the conventional type of chemical-mechanical
polishing (CMP), such problems as contamination of semiconductor
substrates with a polishing solution used in the
chemical-mechanical polishing (CMP), high cost of the polishing
solution or chemicals used for cleaning, and further negative
effects on environment from the processing can be alleviated in the
processing for formation of a copper wiring or a contact.
[0199] Although the present invention has been described above in
detail with reference to the drawings, the foregoing description is
for explanatory purposes and is not intended to limit the
characteristics of the present invention. For example, the
embodiments described above disclose only plate-like electrodes,
but the present invention is not limited to such a structure.
Feeding electrodes divided into several pieces or processing
electrodes divided into several pieces, or elongated electrodes are
also within the scope of the present invention. It should be
understood that the foregoing description merely illustrates and
explains preferred embodiments, and all modifications and changes
within the scope of the spirit of the present invention are
protected.
[0200] The entire disclosure of Japanese Patent Application Nos.
2002-23785, 2002-96230 and 2002-330039 filed on January 31, March
29 and Nov. 13, 2002, respectively, including specification,
claims, drawings and summary are incorporated herein by reference
in its entirety.
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