U.S. patent number RE39,123 [Application Number 10/187,801] was granted by the patent office on 2006-06-13 for plating apparatus.
This patent grant is currently assigned to Ebara Corporation. Invention is credited to Atsushi Chono, Fumio Kuriyama, Kenichi Suzuki, Hiroyuki Ueyama, Junitsu Yamakawa.
United States Patent |
RE39,123 |
Kuriyama , et al. |
June 13, 2006 |
Plating apparatus
Abstract
The plating apparatus has a plating section in which a plating
process is performed and a control section for regulating the
plating solution. The plating section includes a plating bath
containing plating solution, an anode provided in the plating
solution, and a plating object serving as a cathode placed in the
plating solution opposite the anode. The control section includes a
regulating tank for regulating the composition and/or concentration
of the plating solution, and a replenishing tank for injecting
solution into the plating solution in the regulating tank. The
plating apparatus also includes a mechanism for circulating plating
solution between the regulating tank in the control section and the
plating bath in the plating section. The plating section is
installed in a first room, while the control section is installed
in a second room, which is separate from the first room
Accordingly, contamination in the plating section is prevented.
Inventors: |
Kuriyama; Fumio (Tokyo,
JP), Ueyama; Hiroyuki (Tokyo, JP),
Yamakawa; Junitsu (Tokyo, JP), Suzuki; Kenichi
(Tokyo, JP), Chono; Atsushi (Tokyo, JP) |
Assignee: |
Ebara Corporation (Tokyo,
JP)
|
Family
ID: |
26576736 |
Appl.
No.: |
10/187,801 |
Filed: |
November 26, 1999 |
PCT
Filed: |
November 26, 1999 |
PCT No.: |
PCT/JP99/06600 |
371(c)(1),(2),(4) Date: |
July 27, 2000 |
PCT
Pub. No.: |
WO00/32850 |
PCT
Pub. Date: |
June 08, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
09601084 |
Jul 27, 2000 |
06379520 |
Apr 30, 2002 |
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Foreign Application Priority Data
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Nov 30, 1998 [JP] |
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10-340576 |
Dec 2, 1998 [JP] |
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10-342611 |
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Current U.S.
Class: |
205/81; 204/263;
204/269; 204/238 |
Current CPC
Class: |
C25D
21/14 (20130101); C25D 17/001 (20130101); C25D
21/18 (20130101); C25D 21/16 (20130101) |
Current International
Class: |
C25D
21/12 (20060101); C25B 15/00 (20060101); C25B
7/00 (20060101) |
Field of
Search: |
;204/237,252,232,263,269,238 ;205/81,82 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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5-179496 |
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Jul 1993 |
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JP |
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10-121297 |
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May 1998 |
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JP |
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Primary Examiner: Ryan; Patrick
Assistant Examiner: Parsons; Thomas H.
Attorney, Agent or Firm: Wenderoth, Lind & Ponack,
L.L.P.
Claims
What is claimed is:
1. A plating apparatus comprising: a plating section having a
plating bath for plating a semiconductor substrate; and a control
section having a regulating tank connected to said plating bath in
said plating section, said regulating tank accommodating a plating
solution to be supplied to said plating bath in said plating
section; wherein said control section comprises: an analyzer for
analyzing said plating solution to be supplied from said regulating
tank in said control section to said plating bath in said plating
section; a replenishing tank accommodating an additive solution;
and a replenishing mechanism for replenishing said regulating tank
with said additive solution in said replenishing tank, wherein said
plating section is disposed in a clean room, and said control
section is disposed in a space that is separated from said clean
room.
2. A plating apparatus according to claim 1, wherein said
replenishing mechanism replenishes said regulating tank with said
additive solution in accordance with the number of processed
semiconductor substrates.
3. A plating apparatus according to claim 1, wherein said analyzer
adapted to analyze to the composition and concentration of said
plating solution.
4. A plating apparatus according to claim 1, wherein said
replenishing mechanism adapted to replenish said regulating tank
with said additive solution based on the composition and
concentration analyzed by said analyzer.
5. A plating apparatus according to claim 1, wherein said additive
solution comprises an organic additive solution.
6. A plating apparatus according to claim 5, wherein said organic
additive solution comprises a mixture of a polymer, a leveler, a
carrier, and HCl.
7. A plating apparatus according to claim 1, further comprising a
washing apparatus disposed in said plating section for washing a
semiconductor substrate after the plating process.
8. A plating apparatus according to claim 7, wherein said washing
apparatus comprises a nozzle for ejecting a wash water toward said
semiconductor substrate.
9. A plating apparatus according to claim 1, wherein: said plating
bath in said plating section has plating chambers, which are
provided by dividing said plating section with an ion exchange
membrane or a porous membrane into an anode chamber and a cathode
chamber; an anode is disposed in said anode chamber, and said
semiconductor substrate, which adapted to serve as a cathode, is
disposed in said cathode chamber; said anode and said semiconductor
substrate are opposed to each other across said ion exchange
membrane or said porous membrane; and said plating section has a
power supply connected to said anode adapted for connection and
said semiconductor substrate.
10. A plating apparatus according to claim 1, further comprising a
filter connected to said regulating tank in said control
section.
11. A plating apparatus according to claim 1, further comprising a
temperature regulator disposed in said plating section for
regulating the temperature of said plating solution in said plating
bath.
12. A plating apparatus according to claim 1, wherein said
replenishing mechanism adapted to replenish said regulating tank
with said additive solution in accordance with the continuous
performance of the plating process and the number of processed
semiconductor substrates to maintain the composition and
concentration of said plating solution at a predetermined
value.
13. A plating apparatus according to claim 1, further comprising a
temperature regulator disposed in said control section for
regulating the temperature of said plating solution in said
regulating tank.
14. A plating apparatus according to claim 1, further comprising a
circulating mechanism for circulating said plating solution between
said regulating tank in said control section and said plating bath
in said plating section.
15. A plating apparatus according to claim 1, wherein a plurality
of said plating sections are provided for the one control
section.
16. A plating apparatus according to claim 1, wherein said control
section is disposed in a utility room having a level of cleanliness
that is lower than that of said clean room.
17. A plating apparatus according to claim 1, further comprising: a
retainer disposed in said plating bath for holding a semiconductor
substrate; an anode disposed in said plating bath, said anode being
horizontally opposed to said semiconductor substrate; and a power
supply adapted for connection to said semiconductor substrate and
said anode.
18. A plating apparatus according to claim 17, wherein said
retainer has a seal provided therearound for hermetically sealing
said retainer on the top of said plating bath.
19. A plating apparatus according to claim 7, wherein said washing
apparatus comprises a wash water tank for receiving and
accommodating a wash water that has been used.
20. A plating apparatus according to claim 19, wherein said control
section comprises a metallic ion extractor connected to said wash
water tank for extracting a metallic ion from the wash water that
has been used.
21. A plating apparatus according to claim 19, wherein said control
section comprises a wash water recovering apparatus connected to
said wash water tank for recovering the wash water that has been
used.
22. A plating apparatus according to claim 1, further comprising a
solution recovering apparatus disposed in said control section for
regulating said plating solution in said regulating tank.
23. A plating apparatus according to claim 1, further comprising an
apparatus for returning a plating solution, overflowing from an
upper portion of said plating bath, to said regulating tank.
24. A plating method for plating a semiconductor substrate in a
plating bath disposed in a plating section, said plating method
comprising: disposing the plating section in a cleanroom; preparing
a control section having a regulating tank accommodating a plating
solution to be supplied to the plating bath in said plating
section, and an analyzer for analyzing the plating solution to be
supplied from the regulating tank; disposing the control section in
a space that is separated from the clean room; supplying at least a
portion of a plating solution to the analyzer from the regulating
tank; analyzing the plating solution; and replenishing the
regulating tank with an additive solution accommodated in a
replenishing tank.
25. A plating method according to claim 24, wherein the regulating
tank is replenished with the additive solution in accordance with
the number of processed semiconductor substrates.
26. A plating method according to claim 24, wherein the analysis of
the plating solution includes analyzing the composition and
concentration of the plating solution.
27. A plating method according to claim 24, wherein the regulating
tank is replenished with the additive solution based on the
composition and concentration analyzed by the analyzer.
28. A plating method according to claim 24, wherein a starter
additive is used as the additive solution at the beginning of the
plating process.
29. A plating method according to claim 24, wherein a replenishing
additive is used as the additive solution when the plating process
is continuously performed.
30. A plating method according to claim 24, wherein the regulating
tank is replenished with the additive solution in accordance with
the continuous performance of the plating process and the number of
processed semiconductor substrates to maintain the composition and
concentration of the plating solution at a predetermined value.
31. A plating method according to claim 24, further comprising
circulating the plating solution between the regulating tank and
the plating bath.
32. A plating apparatus comprising: a plating section for plating a
plating object, the plating section comprising a plating bath in
which the plating process is performed; a control section for
regulating a plating solution and a solution containing the plating
solution, the control section comprising a regulating tank for
regulating a composition and/or concentration of a plating solution
and a replenishing mechanism for injecting a replenishing solution
into the plating solution; and a circulating mechanism provided for
circulating the plating solution between the regulating tank in the
control section and the plating bath in the plating section,
wherein the plating section is housed in a first room and the
control section is housed in a second room, which is separated from
the first room.
33. A plating apparatus according to claim 32, wherein: the plating
section has plating chambers, which are provided by dividing the
plating section with an ion exchange membrane or a porous membrane
into an anode chamber and a cathode chamber; the anode is insoluble
and disposed in the anode chamber accommodating the electrolytic
solution and the cathode, serving as the plating object, is
disposed in the cathode chamber accommodating plating solution and
opposes the anode across the ion exchange membrane or the porous
membrane; the control section has a regulating tank, which is
divided with a membrane having high ion selectivity into an anode
chamber and a cathode chamber; the anode is soluble and disposed in
the anode chamber accommodating the plating solution and the
cathode is disposed in the cathode chamber accommodating
electrolytic solution and opposes the anode across the membrane
having high ion selectivity; the soluble anode emits metallic ions
into the plating solution; and a replenishing mechanism is provided
for replenishing the anode chamber with the plating solution and/or
additives and for replenishing the cathode chamber with the
electrolytic solution and/or additives.
34. A plating apparatus according to claim 32, wherein the plating
section further comprises a washing apparatus for washing the
plating object after the plating process; and the control section
further comprises: an analyzer for extracting a portion of the
plating solution from the regulating tank and analyzing the
composition and/or measuring the concentration of the plating
solution; an ion removing apparatus for removing metallic ions
contained in washing solution in the washing apparatus after the
washing solution is used to wash the plating object or for removing
metallic ions from the washing solution and recovering the washing
solution; and a plating solution recovering apparatus for
extracting plating solution from the regulating tank, removing
foreign matter from the plating solution, and regulating the
metallic ion concentration, hydrogen ion index, and the like of the
plating solution.
35. A plating apparatus according to claim 32, wherein the first
room has a high level of cleanliness and the second room has a
level of cleanliness that is lower than that of the first room.
36. A plating apparatus according to claim 32, wherein a plurality
of the plating sections are disposed in the first room for one
control section disposed in the second room.
37. A plating apparatus comprising: a plating section having a
plating bath for plating a semiconductor substrate; and a control
section having a regulating tank to regulate the composition and/or
concentration of the plating solution, wherein said control section
comprises: an analyzer for analyzing the plating solution to be
supplied from said regulating tank in said control section to said
plating bath in said plating section; a replenishing tank
accommodating an additive solution; a replenishing mechanism for
replenishing said regulating tank with said additive solution in
said replenishing tank; and a circulating mechanism for circulating
the plating solution between said regulating tank in said control
section and said plating bath in the plating section.
38. A plating apparatus according to claim 37, wherein said
replenishing mechanism replenishes said regulating tank with said
additive solution in accordance with the number of processed
semiconductor substrates.
39. A plating apparatus according to claim 37, wherein said
analyzer is operable to analyze the composition and concentration
of the plating solution.
40. A plating apparatus according to claim 37, wherein said
replenishing mechanism replenishes said regulating tank with said
additive solution based on the composition and concentration
analyzed by said analyzer.
41. A plating apparatus according to claim 37, wherein said
additive solution comprises an organic additive solution.
42. A plating apparatus according to claim 41, wherein said organic
additive solution comprises a mixture of a polymer, a leveler, a
carrier, and HCl.
43. A plating apparatus according to claim 37, further comprising a
washing apparatus disposed in said plating section for washing a
semiconductor substrate after the plating process.
44. A plating apparatus according to claim 43, wherein said washing
apparatus comprises a nozzle for ejecting a wash water toward said
semiconductor substrate.
45. A plating apparatus according to claim 43, wherein said washing
apparatus comprises a wash water tank for receiving and
accommodating a wash water that has been used.
46. A plating apparatus according to claim 45, wherein said control
section comprises a metallic ion extractor connected to said wash
water tank for extracting a metallic ion from the wash water that
has been used.
47. A plating apparatus according to claim 45, wherein said control
section comprises a wash water recovering apparatus connected to
said wash water tank for recovering the wash water that has been
used.
48. A plating apparatus according to claim 37, wherein: said
plating bath in said plating section has plating chambers, which
are provided by dividing said plating section with an ion exchange
membrane or a porous membrane into an anode chamber and a cathode
chamber; an anode is disposed in said anode chamber, and said
semiconductor substrate serving as a cathode is disposed in said
cathode chamber; said anode and said semiconductor substrate are
opposed to each other across said ion exchange membrane or said
porous membrane; and said plating section has a power supply
connected to said anode and said semiconductor substrate.
49. A plating apparatus according to claim 37, further comprising a
filter connected to said regulating tank in said control
section.
50. A plating apparatus according to claim 37, further comprising a
temperature regulator disposed in said plating section for
regulating the temperature of the plating solution in said plating
bath.
51. A plating apparatus according to claim 37, wherein said
replenishing mechanism adapted to replenish said regulating tank
with said additive solution in accordance with the continuous
performance of the plating process and the number of processed
semiconductor substrates to maintain the composition and
concentration of the plating solution at a predetermined value.
52. A plating apparatus according to claim 37, further comprising a
temperature regulator disposed in said control section for
regulating the temperature of the plating solution in said
regulating tank.
53. A plating apparatus according to claim 37, wherein a plurality
of said plating sections are disposed for one control section.
54. A plating apparatus according to claim 37, wherein said control
section is disposed in a utility room having a level of cleanliness
that is lower than that of said clean room.
55. A plating apparatus according to claim 37, further comprising:
a retainer disposed in said plating bath for holding a
semiconductor substrate; an anode disposed in said plating bath,
said anode being horizontally opposed to said semiconductor
substrate; and a power supply adapted for connection to said
semiconductor substrate and said anode.
56. A plating apparatus according to claim 55, wherein said
retainer has a seal provided therearound for hermetically sealing
said retainer on the top of said plating bath.
57. A plating apparatus according to claim 37, further comprising a
solution recovering apparatus disposed in said control section for
regulating the plating solution in said regulating tank.
58. A plating apparatus according to claim 37, further comprising
an apparatus for returning a plating solution, overflowing from an
upper portion of said plating bath, to said regulating tank.
.Iadd.59. A plating apparatus comprising: a plating section having
at least one plating bath containing a plating solution for plating
a substrate; and a control section having a regulator tank fluidly
connected to said at least one plating bath and accommodating the
plating solution to be supplied to said at least one plating bath,
said regulator tank being adapted to regulate composition and/or
concentration of the plating solution, said control section
comprising: a temperature regulator for regulating temperature of
the plating solution in said regulator tank; an analyzer fluidly
connected to said regulator tank and adapted to extract a portion
of the plating solution from said regulator tank for analyzing the
composition and/or the concentration of the plating solution; a
first replenishing tank accommodating a plating solution of
predetermined concentration; a second replenishing tank
accommodating an additive solution; and a replenishing mechanism
for supplying the plating solution of predetermined concentration
to said regulator tank from said first replenishing tank or the
additive solution to said regulator tank from said second
replenishing tank, respectively, based on the results or the
composition and/or concentration of the plating solution analyzed
by said analyzer..Iaddend.
.Iadd.60. The plating apparatus according to claim 59, further
comprising a substrate retainer to mount the substrate horizontally
while the substrate is being plated. .Iaddend.
.Iadd.61. The plating apparatus according to claim 60, further
comprising an anode to be positioned below the substrate in said at
least one plating bath, and a power source to be connected between
said anode and the substrate for supplying a plating current to the
substrate. .Iaddend.
.Iadd.62. The plating apparatus according to claim 61, wherein said
anode has at least one hole for allowing the plating solution to
pass therethrough. .Iaddend.
.Iadd.63. The plating apparatus according to claim 62, further
comprising a casing for holding said anode and forming a space for
containing the plating solution, wherein the plating solution in
said casing is to be supplied through said at least one hole of
said anode. .Iaddend.
.Iadd.64. The plating apparatus according to claim 59, further
comprising a filter provided in a circulating path for circulating
the plating solution between said at least one plating bath and
said regulator tank. .Iaddend.
.Iadd.65. The plating apparatus according to claim 59, further
comprising a plating solution recovering apparatus for extracting
the plating solution and regenerating the extracted plating
solution. .Iaddend.
.Iadd.66. The plating apparatus according to claim 65, further
comprising a fluid passage connected to said regulator tank for
extracting the plating solution from said at least one plating bath
and supplying the extracted plating solution to said plating
solution recovering apparatus. .Iaddend.
.Iadd.67. A plating apparatus comprising: a plating section having
at least one plating bath containing a plating solution for plating
a substrate; and a control section having a regulator tank fluid
connected to said at least one plating bath and accommodating the
plating solution to be supplied to said at least one plating bath,
said regulator tank being adapted to regulate composition and/or
concentration of the plating solution, said control comprising: an
analyzer fluidly connected to said regulator tank and adapted to
extract a portion of the plating solution from said regulator tank
for analyzing the composition and/or the concentration of the
plating solution; a first replenishing tank accommodating a plating
solution of predetermined concentration; a second replenishing tank
accommodating an additive solution; and a replenishing mechanism
for supplying the plating solution of predetermined concentration
to said regulator tank from said first replenishing tank via a
first supply line, or for supplying the additive solution to said
regulator tank from said second replenishing tank via a second
supply line, based on results of the composition and/or
concentration of the plating solution analyzed by said
analyzer..Iaddend.
.Iadd.68. The plating apparatus according to claim 67, further
comprising a substrate retainer to mount the substrate horizontally
while the substrate is being plated. .Iaddend.
.Iadd.69. The plating apparatus according to claim 68, further
comprising an anode to be positioned below the substrate in said at
least one plating bath, and a power source to be connected between
said anode and the substrate for supplying a plating current to the
substrate. .Iaddend.
.Iadd.70. The plating apparatus according to claim 69, wherein said
anode has at least one hole for allowing the plating solution to
pass therethrough. .Iaddend.
.Iadd.71. The plating apparatus according to claim 70, further
comprising a casing for holding said anode and forming a space for
containing the plating solution, wherein the plating solution in
said casing is to be supplied through said at least one hole of
said anode. .Iaddend.
.Iadd.72. The plating apparatus according to claim 67, further
comprising a filter provided in a circulating path for circulating
the plating solution between said at least one plating bath and
said regulator tank. .Iaddend.
.Iadd.73. The plating apparatus according to claim 67, further
comprising a plating solution recovering apparatus for extracting
the plating solution and regenerating the extracted plating
solution. .Iaddend.
.Iadd.74. The plating apparatus according to claim 73, further
comprising a fluid passage connected to said regulator tank for
extracting the plating solution from said at least one plating bath
and supplying the extracted plating solution to said plating
solution recovering apparatus. .Iaddend.
.Iadd.75. A plating apparatus comprising: a plating section having
a plating bath to contain a plating solution; and a control section
having a regulator tank in fluid communication with said plating
bath, said regulator tank being adapted to receive the plating
solution and supply the plating solution to said plating bath, said
control section comprising: an analyzer in fluid communication with
said regulator tank, said analyzer being adapted to receive a
portion of the plating solution and analyze the composition and/or
concentration of the portion of the plating solution; a first
replenishing tank in fluid communication with said regulator tank
via a first supply line, said first replenishing tank being adapted
to supply a plating solution of predetermined concentration to said
regulator tank via said first supply line in response to the
analyzed composition and/or concentration of the portion of the
plating solution; and a second replenishing tank in fluid
communication with said regulator tank via a second supply line,
said second replenishing tank being adapted to supply an additive
solution to said regulator tank via said second supply line in
response to the analyzed composition and/or concentration of the
portion of the plating solution..Iaddend.
.Iadd.76. The plating apparatus according to claim 75, further
comprising a substrate retainer to mount the substrate horizontally
while the substrate is being plated..Iaddend.
.Iadd.77. The plating apparatus according to claim 76, further
comprising an anode to be positioned below the substrate in said at
least one plating bath, and a power source to be connected between
said anode and the substrate for supplying a plating current to the
substrate..Iaddend.
.Iadd.78. The plating apparatus according to claim 77, wherein said
anode has at least one hole for allowing the plating solution to
pass therethrough..Iaddend.
.Iadd.79. The plating apparatus according to claim 78, further
comprising a casing for holding said anode and forming a space for
containing the plating solution, wherein the plating solution in
said casing is to be supplied through said at least one hole of
said anode..Iaddend.
.Iadd.80. The plating apparatus according to claim 75, further
comprising a filter provided in a circulating path for circulating
the plating solution between said at least one plating bath and
said regulator tank..Iaddend.
.Iadd.81. The plating apparatus according to claim 75, further
comprising a plating solution recovering apparatus for extracting
the plating solution and regenerating the extracted plating
solution..Iaddend.
.Iadd.82. The plating apparatus according to claim 81, further
comprising a fluid passage connected to said regulator tank for
extracting the plating solution from said at least one plating bath
and supplying the extracted plating solution to said plating
solution recovering apparatus..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a plating apparatus and
particularly to a plating apparatus used in the semiconductor
fabrication process for forming a metal plating on a substrate,
such as a semiconductor wafer or the like.
2. Description of Related Art
The plating process is used frequently in semiconductor fabrication
process to form wiring or films on a substrate. FIG. 1 shows the
construction of this type of plating apparatus. As shown in the
drawing, the plating apparatus comprises a plating section 1 and a
control section 2. The plating section 1 includes a plating bath
1-2. The control section 2 includes a replenishing tank 2-2 and a
replenishing tank 2-3.
The plating bath 1-2 accommodates a plating solution 1-1, a
substrate 1-4 mounted on a wafer holder (not shown) in the plating
solution 1-1, and a soluble anode 1-3 disposed in the plating
solution 1-1 opposite the substrate 1-4. A power source 1-5 is
connected between the substrate 1-4 and anode 1-3. The plating
section 1 also includes a pump 1-6 and a temperature regulator 1-7.
The pump 1-6 supplies the plating solution 1-1 to the temperature
regulator 1-7. The temperature regulator 1-7 adjusts the plating
solution 1-1 to a temperature optimal for the plating process and
returns the plating solution 1-1 to the plating bath 1-2.
The replenishing tank 2-3 accommodates a plating solution 2-5, such
as an aqueous solution primarily comprising predetermined
concentrations of CuSO.sub.4-5H.sub.2O. The plating solution 2-5 is
supplied to the plating bath 1-2 by the pump 2-7 through the pipe
3. The replenishing tank 2-2 accommodates an additive solution 2-4,
and the solution 2-4 is supplied to the plating bath 1-2 by the
pump 2-6 through the tube 4. When the apparatus is first powered
on, new plating solution 2-5 is introduced into the plating bath
1-2. During plating operations, an analyzing apparatus (not shown)
analyzes the composition and concentration of the plating solution
1-1 from the plating bath 1-2. Based on these analyses, the
additive solution 2-4 or the plating solution 2-5 is supplied from
the replenishing tank 2-2 or the replenishing tank 2-3 in order to
maintain the composition and concentration of the plating solution
1-1 at predetermined values.
When the power source 1-5 supplies a plating current between the
substrate 1-4 and anode 1-3, metallic ions, such as Cu.sup.2+ are
emitted from the soluble anode (for example, a phosphorus copper
electrode) 1-3 and deposited on the surface of the substrate 1-4 to
form a metallic plating film. It is necessary to replace the anode
1-3 periodically because the anode 1-3 is consumed as it emits
metallic ions into the plating solution 1-1.
The plating solution used in this plating apparatus contains
metallic ions that are deposited on a member to be plated.
Sometimes the deposited metal is transferred or diffused. Further,
when the plating solution or mist from the solution is vaporized,
crystals are deposited, generating solid particles. This metallic
deposited matter and the crystalline particles are causing
contamination for clean rooms, semiconductor wafers, and circuit
materials.
In the semiconductor fabrication process, metallic plating is
embedded in fine wire channels and the like formed in the surface
of semiconductor wafers. From a process control standpoint, it is
advantageous to conduct these plating processes in a clean room.
However, by installing the plating apparatus comprised of the
plating section 1 and control section 2 in a clean room, the
replenishing tank 2-2, replenishing tank 2-3, and liquid analyzer
(not shown) must also be disposed in the clean room by association.
This raises the problem of managing the above-described
contamination during maintenance operations.
FIG. 2 shows an example construction of a plating apparatus
employing a conventional insoluble anode. As shown in the drawing,
the plating apparatus comprises a plating section 1 and a control
section 2. The plating section 1 includes a hermetically sealed
plating chamber 1-24 and a regulating tank 1-31. The control
section 2 includes replenishing tanks 2-2, 2-3, 2-17, and 2-23. The
plating chamber 1-24 is divided into an anode chamber 1-24a and a
cathode chamber 1-24b by an ion exchange membrane 1-25. An
insoluble anode 1-23 is disposed in the anode chamber 1-24a, while
a substrate 1-4 is disposed in the cathode chamber 1-24b and
opposes the anode 1-23 across the ion exchange membrane 1-25.
The regulating tank 1-31 is divided into an anode chamber 1-31a and
a cathode chamber 1-31b by an ion exchange membrane 1-27. A soluble
anode 1-28 is disposed in the anode chamber 1-31a, while a cathode
1-29 is disposed in the cathode chamber 1-31b and opposes the anode
1-28 across the ion exchange membrane 1-27. A power source 1-33 is
connected between the anode 1-28 and cathode 1-29. The anode
chamber 1-31a accommodates plating solution 1-1, while the cathode
chamber 1-31b accommodates electrolytic solution 1-22. When the
power source 1-33 applies a predetermined voltage between the anode
1-28 and cathode 1-29, the anode 1-28 dissolves and emits metallic
ions.
A pump 1-14 supplies the plating solution 1-1 from the anode
chamber 1-31a to the cathode chamber 1-24b via a tube 1-20 and a
filter 1-16 provided on the tube 1-20. A pump 1-15 supplies
electrolytic solution 1-22 from the cathode chamber 1-31b to the
anode chamber 1-24a via a tube 1-21 and a filter 1-17 provided on
the tube 1-21. The apparatus is also configured to return the
electrolytic solution 1-22 from the anode chamber 1-24a and the
plating solution 1-1 from the cathode chamber 1-24b to the cathode
chamber 1-31b and anode chamber 1-31a, respectively.
Hence, the power source 1-5 applies a predetermined voltage between
the anode 1-23 and substrate 1-4, supplying a current from the
anode 1-23 to the substrate 1-4. The current forms a metallic film
on the surface of the substrate 1-4. Metallic ions such as
Cu.sup.2+ ions consumed during the plating process in the plating
chamber 1-24 are replenished from the regulating tank 1-31.
When using an insoluble electrode for the anode 1-23 as described
above, there is no need to replace the electrode. Therefore,
maintenance work can be reduced. However, the anode 1-28 in the
regulating tank 1-31 must be replaced. Further, O.sub.2 gas is
released from the region near the anode 1-23 and H.sub.2 gas is
released from the region near the cathode 1-29. From a safety
standpoint, it is not desirable for both gases to be released in
the same clean room.
In the plating apparatus having the construction described above, a
lot of the washing solution is discharged when washing the
substrate 1-4 after the substrate is plated. Hence, a lot of
washing solution and pure wafer are consumed, particularly when the
substrate 1-4 to be plated is, for example, a semiconductor wafer
for fabricating a semiconductor device. Further, since the washing
solution contains plating solution, it is necessary to process the
solution to remove metallic ions and the like, which can place a
great burden on the wasted water processing equipment. The same
problem exists when processing wasted plating solution that has
been degraded.
Therefore, an effective method to reduce the overall load on the
equipment is to provide the plating apparatus with functions to
recover wasted plating solution and to process wash water. Such
functions can perform specialized functions by themselves to enable
the plating apparatus to process the plating solution and solution
containing plating solution. Here, great benefits can be obtained
by providing functions to regulate the plating solution, to remove
metallic ions from the wash water after processing, and to
re-regulate and recover wasted plating solution in a separate room
from the room housing the plating section 1, which is required to
be extremely clean. From a maintenance standpoint, it is very
beneficial to manage the plating solution, process the plating
solution, and process the wash water by the plating apparatus
itself. However, a conventional plating apparatus has not been
developed to perform these functions.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention
to provide a plating apparatus having a plating section and a
control section, which sections are installed in separate rooms,
such that maintenance work generating contamination is performed as
much as possible in the room housing the control section, thereby
minimizing maintenance work on the plating section and preventing
contamination being generated therefrom.
It is another object of the present invention to provide a highly
safe plating apparatus that does not release O.sub.2 gas and
H.sub.2 gas in the same area.
It is another object of the present invention to provide a plating
apparatus having special functions by itself to process wash water,
recover wasted plating solution, and process plating solution and
solution containing plating solution, wherein these functions are
performed separately from the room housing the plating section
which requires a high level of cleanliness.
To achieve the above-described subjects, there is provided a
plating apparatus having a plating section for plating a plating
object and a control section for regulating a plating solution and
a solution containing-the plating solution. The plating apparatus
is characterized in that: the plating section has a plating bath in
which the plating process is performed by accommodating a plating
solution therein and disposing an anode and a cathode as the
plating object opposite the anode therein. The control section has
a regulating tank for regulating a composition and/or concentration
of the plating solution and a replenishing mechanism for injecting
a replenishing solution into the plating solution therein. A
circulating mechanism is provided for circulating the plating
solution between the regulating tank in the control section and the
plating bath in the plating section. The plating section is housed
in a-first room and the control section is housed in a second room
that is separate from the first room.
By providing the plating section in the first room and the control
section in the second room as described above, operations for
injecting additives into the plating solution to regulate its
components, mixing other solutions, regulating the temperature of
the plating solution, extracting plating solution for analyzing its
components, and other dirty maintenance operations can all be
performed in the second room in which the control section is
provided and separate from the first room in which the plating
section is provided. Hence, almost no contamination will be
generated in the plating section.
Although O.sub.2 gas is generated near the insoluble anode in the
plating chamber and H.sub.2 gas is generated near the cathode in
the regulating tank, the O.sub.2 gas and H.sub.2 gas are not
released in the same area because the plating section is in a
separate room from the control section. Hence, the plating
apparatus maintains safety by releasing the gases separately into
the atmosphere.
The control section is provided with a regulating tank to regulate
the composition and/or concentration of the plating solution; a
replenishing mechanism for injecting plating solution and
replenishing additives; an analyzer for analyzing components and/or
measuring the concentration of the plating solution; a recovering
apparatus for removing metallic ions contained in the wash solution
after processing or for removing the ions and recovering the wash
water; and a plating solution recovering apparatus for extracting
plating solution from the regulating tank, removing foreign matter
from the plating solution, and regulating the metallic ion
concentration and hydrogen ion index. Accordingly, the plating
apparatus is capable of processing wash water and recovering used
plating solution. Hence, most of these processes are effectively
performed in the second room housing the control section, thereby
preventing contamination in the first room, which is required to
have a high degree of cleanliness, and improving the efficiency of
maintenance operations.
As described above, the plating section is housed in the first room
having a high level of cleanliness, while the control section is
housed in the second room having a level of cleanliness lower than
that in the first room. As a result, dirty maintenance operations
are concentrated in the utility room housing the control section,
thereby greatly avoiding contamination in the clean room.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows an example of a plating apparatus constructed in
accordance with the prior art;
FIG. 2 shows another example of a prior art apparatus;
FIG. 3 shows an example construction of a plating apparatus
according to the first embodiment of the present invention;
FIG. 4 shows a variation of a plating apparatus according to the
first embodiment;
FIG. 5 shows another example construction of a plating apparatus
according to the first embodiment;
FIG. 6 shows a variation of a plating apparatus according to the
first embodiment;
FIG. 7 shows an example construction of a plating apparatus
according to the second embodiment;
FIG. 8 shows a variation of a plating apparatus according to the
second embodiment;
FIG. 9 shows an example construction of the metallic ion extractor
of FIG. 7;
FIG. 10 shows an example construction of the wash water recovering
apparatus of FIG. 8; and
FIG. 11 shows an example construction of the plating solution
recovering apparatus of FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
A plating apparatus according to first embodiments of the present
invention will be described while referring to the accompanying
drawings. First embodiments of the present invention will be
described with reference to FIGS. 3-6.
FIG. 3 shows an example construction of a plating apparatus
according to the first embodiments of the present invention. In
FIG. 3, components that have same reference numbers are identical
or corresponding to those in FIG. 1 (such relationship is same in
the following drawings). As shown in FIG. 3, the plating apparatus
comprises a plating section 1 and a control section 2. The plating
section 1 is installed in a first room having a high level of
cleanliness, such as a clean room, while the control section 2 is
installed in a second room having a low level of cleanliness, such
as a utility room.
The plating section 1 includes a plating bath 1-2 accommodating a
plating solution 1-1, a soluble anode 1-3 disposed in the plating
solution 1-1, a substrate 1-4 mounted on a wafer holder in
opposition to the anode 1-3. A power source 1-5 is connected
between the anode 1-3 and substrate 1-4 for supplying a plating
current from the anode 1-3 to the substrate 1-4. A temperature
regulator 1-7 is provided for maintaining the plating solution 1-1
at a temperature that is suitable for plating, and a pump 1-6 is
also provided for supplying plating solution 1-1 from the plating
bath 1-2 to the temperature regulator 1-7 and returning the plating
solution 1-1 to the plating bath 1-2 after the plating solution 1-1
is adjusted to an appropriate temperature.
The control section 2 includes a regulator tank 2-1, a replenishing
tank 2-2, and another replenishing tank 2-3. The regulator tank 2-1
contains the plating solution 1-1 that is regulated at an
appropriate temperature. The replenishing tank 2-2 contains an
additive solution 2-4. The replenishing tank 2-3 contains a plating
solution 2-5 (for example, having a main component of copper
sulfate, at a predetermined concentration). A pump 2-6 supplies the
additive solution 2-4 to the regulator tank 2-1 via a tube 2-8. A
pump 2-7 supplies the plating solution 2-5 to the regulator tank
2-1 via a tube 2-9.
The regulator tank 2-1 is connected to the plating bath 1-2 by
tubes 3 and 4. A pump 2-10 supplies the plating solution 1-1 from
the regulator tank 2-1 to the plating bath 1-2 via the tube 3 and a
filter 2-11 disposed on the tube 3. A pump 1-8 supplies the plating
solution 1-1 from the plating bath 1-2 to the regulator tank 2-1
via the tube 4. In other words, a mechanism for circulating the
plating solution 1-1 between the regulator tank 2-1 and plating
bath 1-2 includes the tube 3, pump 2-10, filter 2-11, tube 4, and
pump 1-8.
With this construction, the power source 1-5 applies a
predetermined voltage between the substrate 1-4 and anode 1-3,
forcing metallic ions, such as Cu.sup.2+ to be emitted from the
soluble anode 1-3 (for example, a phosphorous copper electrode).
The metallic ions emitted from the anode 1-3 are deposited on the
surface of the substrate 1-4 to form a metal plating film. After
continuously performing the plating process and processing a
plurality of substrate 1-4, the composition, concentration, and
amount of the plating solution 1-1 varies. In response to these
variations, additive solution 2-4 from the replenishing tank 2-2
and plating solution 2-5 from the replenishing tank 2-3 are
supplied to the regulator tank 2-1 to maintain the composition and
concentration of the plating solution 1-1 at predetermined values.
The additive solution 2-4 in the replenishing tank 2-2 is an
organic additive solution comprising a mixture of a polymer,
leveler, carrier, and HCl.
As described above, the plating section 1 is installed in the first
room having a high level of cleanliness, such as a clean room,
while the control section 2 is installed in the second room having
a low level of cleanliness, such as a utility room. Accordingly,
the only operations performed in the first room are replacing the
soluble anode 1-3. All other dirty operations, such as regulating
the plating solution in the control section 2, are performed in the
second room, thereby reducing the possibility of contaminating the
first room. Further, by installing the control section 2, which
requires a large amount of installation space, in the second room
with a low level of cleanliness, it is possible to conserve
precious installation space in the first room.
FIG. 4 is an example construction of a plating apparatus that is a
variation of the plating apparatus described above. In this plating
apparatus, a substrate retainer 1-9 is disposed at the top of the
plating bath 1-2. The substrate 1-4 is mounted horizontally in the
substrate retainer 1-9. The anode 1-3 is positioned below the
substrate 1-4 at a predetermined distance. A seal 1-10 is provided
around the substrate retainer 1-9 for hermetically sealing the
substrate retainer 1-9 on top of the plating bath 1-2. A plurality
of ejection holes 1-3a are formed in the anode 1-3 through which
plating solution 1-1 is ejected. A casing 1-11 covers the bottom of
the anode 1-3. With this construction, the anode 1-3 and casing
1-11 form a nozzle construction for ejecting the plating solution
1-1 toward the substrate 1-4.
In the control section 2, a temperature regulator 2-15 and a pump
2-14 are provided on the regulator tank 2-1 for maintaining the
plating solution 1-1 in the regulator tank 2-1 at a predetermined
temperature. An analyzer 2-26 is provided in the control section 2
for analyzing the composition and concentration of the plating
solution 1-1 supplied from the regulator tank 2-1 to the plating
bath 1-2. A replenishing tank 2-17 accommodating an additive
solution 2-20 is also provided. A pump 2-18 supplies the additive
solution 2-20 from the replenishing tank 2-17 to the regulator tank
2-1 via a tube 2-19.
The plating section 1 is installed in the first room having a high
cleanliness, such as a clean room, while the control section 2 is
installed in the second room having a low level of cleanliness,
such as a utility room. The pump 2-10 supplies the plating solution
1-1 from the regulator tank 2-1 to the plating bath 1-2 via the
tube 3 and the filter 2-11 disposed on the tube 3. The plating
solution 1-1 passes through the ejection holes 1-3a in the anode
1-3 and is ejected toward the substrate 1-4. The plating bath 1-2
is filled with the plating solution 1-1. The power source 1-5
applies a predetermined voltage between the anode 1-3 and substrate
1-4, causing a current to flow from the anode 1-3 to the substrate
1-4 and form a metallic plating film on the substrate 1-4.
The analyzer 2-26 analyzes the composition and concentration of the
plating solution 1-1 supplied to the plating bath 1-2 from the
regulator tank 2-1. Based on the results of this analysis, additive
solution 2-4 or plating solution 2-5 is supplied to the regulator
tank 2-1 from the replenishing tank 2-2 and replenishing tank 2-3
respectively. Further, the regulator tank 2-1 is replenished with
additive solution 2-20 from the replenishing tank 2-17. The
additive solution includes a make-up additive necessary for forming
a black film on the surface of the anode 1-3 when conducting an
electrolytic purification at the beginning of the plating process,
and a replenish additive needed for performing continuous plating
operations. The additive solution 2-20 in the replenishing tank
2-17 is equivalent to the starter (makeup) additive, while the
additive solution 2-4 in the replenishing tank 2-2 is equivalent to
the replenish additive.
By installing the plating section 1 in the first room having high
cleanliness and the control section 2 in the second room having low
cleanliness as described above, the same effects described for the
plating apparatus of FIG. 3 can be obtained. Here, the pump 2-10,
filter 2-11, and temperature regulator 2-15 used for circulating
the plating solution are provided in the control section 2. This is
desirable because the control section 2 is installed in the second
room. Therefore, maintenance operations on these components are
performed in the second room.
FIG. 5 shows another variation of the plating apparatus described
above. In this plating apparatus, the plating section 1 is provided
with a hermetically sealed plating chamber 1-24. The substrate 1-4
and an insoluble anode 1-23 are disposed in the plating chamber
1-24 in opposition to each other. An ion exchange membrane 1-25 is
disposed in the plating chamber 1-24 between the substrate 1-4 and
anode 1-23, and partitions the plating chamber 1-24 to form an
anode chamber 1-24a and a cathode chamber 1-24b.
The plating section 1 is also provided with a plating solution tank
1-12 accommodating the plating solution 1-1 whose main component is
copper sulfate, for example, and an electrolytic solution tank 1-13
accommodating an electrolytic solution 1-22 whose main component is
sulfuric acid, for example. A pump 1-14 supplies plating solution
1-1 from the plating solution tank 1-12 to the cathode chamber
1-24b via a tube 1-20 and a filter 1-16 disposed on the tube 1-20.
The apparatus is configured to return plating solution 1-1
overflowing from the cathode chamber 1-24b to the plating solution
tank 1-12. A pump 1-15 supplies electrolytic solution 1-22 from the
electrolytic solution tank 1-13 to the anode chamber 1-24a via a
tube 1-21 and a filter 1-17 disposed on the tube 1-21. The
apparatus is configured to return electrolytic solution 1-22 over
flowing from the anode chamber 1-24a to the electrolytic solution
tank 1-13.
The control section 2 is also provided with a regulating tank 2-25.
An ion exchange membrane 2-27 is disposed in the regulating tank
2-25 partitioning the regulating tank 2-25 into an anode chamber
2-25a and a cathode chamber 2-25b. A soluble anode 2-28, such as a
phosphorous copper electrode, is provided in the anode chamber
2-25a. A cathode 2-29 is disposed in the cathode chamber 2-25b and
opposes the anode 2-28 across the ion exchange membrane 2-27. A
power supply 2-35 is connected between the anode 2-28 and cathode
2-29 to supply a predetermined current from the anode 2-28 to the
cathode 2-29.
The anode chamber 2-25a accommodates the plating solution 1-1,
while the cathode chamber 2-25b accommodates the electrolytic
solution 1-22. The control section 2 is configured such that the
anode chamber 2-25a can be supplied with additive solution 2-4,
plating solution 2-5, and additive solution 2-20 from the
replenishing tank 2-2, replenishing tank 2-3, and replenishing tank
2-17, respectively. The control section 2 is also provided with a
pump 2-24 for supplying an electrolytic solution 2-36 from a
replenishing tank 2-23 to the cathode chamber 2-25b.
A pump 2-30 and a temperature regulator 2-32 are connected to the
anode chamber 2-25a in order to maintain the plating solution 1-1
in the anode chamber 2-25a at a predetermined temperature. A pump
2-31 and a temperature regulator 2-33 are connected to the cathode
chamber 2-25b in order to maintain the electrolytic solution 1-22
in the cathode chamber 2-25b at a predetermined temperature.
The electrolytic solution tank 1-13 of the plating section 1 and
the cathode chamber 2-25b of the control section 2 are connected by
tubes 5 and 6. A pump 2-34 supplies electrolytic solution 1-22
regulated at a predetermined concentration in the cathode chamber
2-25b to the electrolytic solution tank 1-13.
A pump 1-19 supplies the electrolytic solution 1-22 in the
electrolytic solution tank 1-13 to the cathode chamber 2-25b in
order to maintain the concentration of the electrolytic solution in
the electrolytic solution tank 1-13 at a predetermined value.
The plating solution tank 1-12 of the plating section 1 and the
anode chamber 2-25a of the control section 2 are connected by the
tubes 3 and 4. A pump 2-21 supplies the plating solution 1-1
regulated at a predetermined composition and concentration in the
anode chamber 2-25a to the plating solution tank 1-12 via the tube
3 and the filter 2-11. The pump 1-8 supplies the plating solution
1-1 from the plating solution tank 1-12 to the anode chamber 2-25a
via the tube 4 in order to maintain the plating solution 1-1 in the
plating solution tank 1-12 at a predetermined composition and
concentration.
With this construction, the power source 1-5 supplies a current
between the substrate 1-4 and anode 1-23 in the plating chamber
1-24. The current causes metallic ions, such as Cu.sup.2+ in the
plating solution 1-1 of the cathode chamber 1-24b to deposit on the
surface of the substrate 1-4 and form a metallic plating film
thereon. During the plating process, O.sub.2 gas is emitted near
the anode 1-23, lowering the PH value of the electrolytic solution
1-22 in the anode chamber 1-24a.
The power supply 2-35 supplies a current between the anode 2-28 and
cathode 2-29 in the regulating tank 2-25, causing metallic ions,
such as Cu.sup.2+ to dissolve from the anode 2-28. As the metallic
ions dissolve from the anode 2-28, the concentration of metallic
ions in the plating solution 1-1 rises. At the same time, H.sub.2
gas is emitted near the cathode 2-29, raising the PH value of the
electrolytic solution 1-22 in the cathode chamber 2-25b. The pump
2-21 feeds this metallic ion-rich plating solution 1-1 to the
plating solution tank 1-12, thereby replenishing the plating
solution 1-1 in the plating solution tank 1-12 with metallic
ions.
The plating section 1 is installed in the first room having a high
degree of cleanliness, such as a clean room. The control section 2
is installed in the second room having a low degree of cleanliness,
such as a utility room. Since the anode 1-23 in the plating chamber
1-24 is insoluble, it is not necessary to replace the anode 1-23,
thereby almost entirely eliminating the need for maintenance
operations on the plating section 1 installed in the first room.
The anode 2-28 is soluble and must be periodically replaced as it
is consumed. However, it is no problem to perform this dirty
operation for replacing the anode 2-28 because the operation is
performed in the second room.
As described above, O.sub.2 gas is generated and emitted near the
anode 1-23, while H.sub.2 gas is generated and emitted near the
cathode 2-29. However, since the plating section 1 and control
section 2 are installed in the first room and second room,
respectively, the O.sub.2 gas and H.sub.2 gas are released into the
atmosphere in separate locations. Hence, this configuration is
desirable from a safety standpoint.
FIG. 6 is another variation of the plating apparatus described
above. The plating apparatus of FIG. 6 differs from that shown in
FIG. 5 in that it has omitted the plating solution tank 1-12 and
electrolytic solution tank 1-13 from the plating section 1.
Further, the pump 2-21 supplies the plating solution 1-1 from the
anode chamber 2-25a to the cathode chamber 1-24b directly via a
tube 8 and the filter 2-11. The plating solution 1-1 overflowing
from the cathode chamber 1-24b is returned to the anode chamber
2-25a directly via a tube 7.
Further, the pump 2-34 supplies electrolytic solution 1-22 from the
cathode chamber 2-25b directly to the anode chamber 1-24a via a
tube 9 and a filter 2-37 disposed on the tube 9. The electrolytic
solution 1-22 overflowing from the anode chamber 1-24a returns to
the cathode chamber 2-25b via a tube 10. Since O.sub.2 gas is
generated from the region near the insoluble anode 1-23 at this
time, a gas valve 1-32 is provided on the tube 10 to release the
gas.
The plating section 1 is installed in the first room having a high
level of cleanliness, such as a clean room, while the control
section 2 is installed in the second room having a low level of
cleanliness, such as a utility room. With this configuration, the
plating section 1 includes almost no mechanisms that require
maintenance, thereby further simplifying the construction. Hence,
there is even less chance of the plating section 1 contaminating
the first room than with the plating apparatus of FIG. 5.
In the plating apparatus described in FIGS. 5 and 6, the ion
exchange membrane 1-25 partitioning the plating chamber 1-24 into
the anode chamber 1-24a and cathode chamber 1-24b is not limited to
an ion exchange membrane, but can also be a porous membrane.
Further, the ion exchange membrane 2-27 dividing the regulating
tank 2-25 into the anode chamber 2-25a and cathode chamber 2-25b is
not limited to an ion exchange membrane, but can also be a membrane
having high ion selective permeability.
In the plating apparatus having the construction described in FIGS.
3-6, the first room in which the plating section 1 is installed is
a clean room. However, the first room is not limited to being a
clean room, but can be a room or area having high cleanliness, such
as a clean booth, clean bench, or clean box.
In the construction of the plating apparatus described in FIGS.
3-6, the power source 1-5 is disposed in the plating section 1,
which in turn is installed in the first room. However, it is also
possible to provide the power source 1-5 in the second room in
which the control section 2 is installed, such that the power
source 1-5 supplies electricity from the second room. With this
configuration, maintenance operations on the power source 1-5 can
also be performed in the second room housing the control section 2.
If the power source 1-5 is a storage battery (accumulator), in
particular, it is desirable to perform the dirty maintenance work
required for the storage battery in the second room.
In the construction described in FIGS. 3-6, one plating section 1
is provided with one control section 2. However, it is also
possible to configure the plating apparatus with one control
section 2 for a plurality of plating section S1. In this case, the
plurality of plating section S1 are installed in the first room,
while the single control section 2 is installed in the second room,
and the one control section 2 controls the plurality of plating
section S1.
While the description of some apparatus were omitted from the
construction described in FIGS. 3-6, mechanisms that require
maintenance, such as a flow meter for measuring the flow of
solution including plating solution or electrolytic solution, a
pressure gauge for measuring pressure, and a temperature gauge are
installed in the second room having a low degree of cleanliness.
Accordingly, there is no fear of contaminating the first room
having a high level of cleanliness by performing such maintenance
in that room.
Although the object of plating is described as a substrate, such as
a semiconductor wafer, the plating object is not limited to a
substrate.
The invention described above has the following superior
effects.
In the plating apparatus according to the present invention,
mechanisms requiring maintenance work are installed as much as
possible in the control section to minimize maintenance required
for the plating section. Further, the plating section is installed
in the first room, while the control section is installed in the
second room. Accordingly, contamination caused by the plating
section is reduced, and maintenance work performed on the control
section does not contaminate the first room in which the plating
section is installed.
In the plating apparatus of the present invention, O.sub.2 gas is
emitted near the insoluble anode in the plating chamber of the
plating section, while H.sub.2 gas is emitted near the cathode of
the regulating tank in the control section. However, since the
plating section and control section are installed in separate
rooms, the O.sub.2 gas and H.sub.2 gas are not released in the same
atmosphere, but are released into the atmosphere in separate areas,
thereby preserving safety of the operation. Since the anode used in
the plating chamber is an insoluble anode, there is no need to
perform the dirty operation of replacing the anode in the first
room, where the plating section is installed.
In the embodiments described above, the first room housing the
plating section is a clean room, while the second room housing the
control section is a utility room. Hence, maintenance work capable
of contaminating the clean room that requires a high level of
cleanliness is performed in the utility room, thereby avoiding
contaminating the clean room.
Next, a second embodiment of the present invention will be
described with reference to FIGS. 7-11.
FIG. 7 shows an example construction of a plating apparatus
according to the present invention. As shown in the drawing, the
plating apparatus comprises a plating section 1 and a control
section 2.
The plating section 1 is provided with a plating bath 11-2 and a
washing apparatus 11-6. The plating bath 11-2 accommodates a
plating solution 11-1 and is further provided with an anode 11-3
disposed in the plating solution 11-1 and a substrate 11-4, such as
a semiconductor wafer, mounted on a wafer holder and disposed
opposite the anode 11-3. The substrate 11-4 serves as a cathode. A
power supply 11-5 is connected between the anode 11-3 and substrate
11-4. The power supply 11-5 supplies a plating current between the
anode 11-3 and substrate 11-4 to form a metallic plating film, such
as a copper film, on the surface of the substrate 11-4.
The washing apparatus 11-6 is provided to wash a substrate 11-4'
after the plating process. In addition to the substrate 11-4', the
washing apparatus 11-6 includes a nozzle 11-8 for ejecting a wash
water 11-7, such as pure water, at the substrate 11-4'; and a wash
water tank 11-9 for receiving and accommodating a wash water 11-7'
that has already been used after being ejected from the nozzle
11-8. A pump 11-10 is provided to supply wash water 11-7' from the
wash water tank 11-9 to the control section 2.
The control section 2 is provided with a regulating tank 12-1, a
replenishing tank 12-2, a replenishing tank 12-3, a plating
solution recovering apparatus 12-4, a metallic ion extractor 12-5,
and an analyzer 12-6. The regulating tank 12-1 accommodates the
regulated plating solution 11-1. The replenishing tank 12-2
accommodates an additive solution 12-7. The replenishing tank 12-3
accommodates a plating solution 12-8, whose main component is
copper sulfate, for example, having a predetermined concentration.
A pump 12-9 supplies the additive solution 12-7 to the regulating
tank 12-1 via a tube 12-10. A pump 12-11 supplies the plating
solution 12-8 to the regulating tank 12-1 via a tube 12-12.
The regulating tank 12-1 and plating bath 11-2 are connected by the
tubes 3 and 4. A pump 12-13 supplies plating solution 11-1 from the
regulating tank 12-1 to the plating bath 11-2 via the tube 3 and a
filter 12-14 disposed on the tube 3. A pump 11-11 supplies plating
solution 11-1 from the plating bath 11-2 to the regulating tank
12-1 via the tube 4. Hence, a mechanism for circulating plating
solution 11-1 between the regulating tank 12-1 and the plating bath
11-2 includes the tube 3, pump 12-13, filter 12-14, tube 4, and
pump 11-11.
A pump 12-15 supplies plating solution 11-1 from the regulating
tank 12-1 to the plating solution recovering apparatus 12-4. The
plating solution recovering apparatus 12-4 removes foreign matter
from the plating solution 11-1 and adjusts the metallic ion
concentration, hydrogen ion index, and the like. After the plating
solution 11-1 is processed in the plating solution recovering
apparatus 12-4, a pump 12-16 supplies the processed plating
solution 11-1 to the regulating tank 12-1 via a filter 12-17.
Hence, a mechanism for circulating plating solution 11-1 between
the regulating tank 12-1 and plating solution recovering apparatus
12-4 comprises the pump 12-15, pump 12-16, and filter 12-17.
The pump 11-10 supplies wash water 11-7' from the wash water tank
11-9 that has been used for washing to the metallic ion extractor
12-5 via a tube 11-12. The metallic ion extractor 12-5 extracts
(removes) metallic ions such as Cu.sup.2+ from the wash water 11-7'
and discharges the wash water 11-7' as a normal wastewater 12-18.
The control section 2 is also provided with a temperature regulator
12-19 and a pump 12-20. The pump 12-20 flows plating solution 11-1
from the regulating tank 12-1 through the temperature regulator
12-19 to adjust the temperature and maintain the plating solution
at a predetermined temperature.
Further, a portion of the plating solution 11-1 transmitted from
the regulating tank 12-1 by the pump 12-13 is supplied to the
analyzer 12-6. The analyzer 12-6 analyzes the components and/or
concentration of the plating solution. Based on the results of this
analysis, either the pump 12-9 or the pump 12-11 are activated to
replenish the regulating tank 12-1 with either additive solution
12-7 from the replenishing tank 12-2 or plating solution 12-8 from
the replenishing tank 12-3, thereby regulating the composition
and/or concentration of the plating solution 11-1 in the regulating
tank 12-1.
With the construction described above, the power supply 11-5
applies a predetermined voltage across the substrate 11-4 and the
anode 11-3, causing metallic ions such as Cu.sup.2+ to emit from
the soluble anode 11-3 (which is a phosphorous copper electrode,
for example) and deposit on the surface of the substrate 11-4 to
form a metallic film. After continuous plating operations and after
performing the process on a plurality of substrate S11-4, the
composition and concentration of the plating solution 11-1, as well
as the amount of the plating solution 11-1, fluctuates. Based on
the state of these fluctuations, the regulating tank 12-1 is
replenished with additive solution 12-7 or plating solution 12-8
from the replenishing tank 12-2 or replenishing tank 12-3,
respectively, in order to maintain the composition and
concentration of the plating solution 11-1 at predetermined values.
The additive solution 12-7 contained in the replenishing tank 12-2
is an organic additive solution comprising a mixture of polymers,
levelers, carriers, and HCl.
The plating section 1 of the plating apparatus described above is
installed in the first room having a high level of cleanliness,
such as a clean room, while the control section 2 is installed in
the second room having a low level of cleanliness, such as a
utility room. As a result, the wash water 11-7' stored in the wash
water tank 11-9 after being used for washing is transferred to the
metallic ion extractor 12-5 by the pump 11-10. The metallic ion
extractor 12-5 removes the metallic ions and discharges the
solution as the normal wastewater 12-18.
FIG. 8 is a variation of the plating apparatus of FIG. 7. In FIG.
8, same numbers corresponding to those in FIG. 7 represent the same
or similar parts. The plating apparatus of FIG. 8 differs from that
of FIG. 7 in that the apparatus of FIG. 8 is provided with a wash
water recovering apparatus 12-21 in the control section 2 in place
of the metallic ion extractor 12-5. Hence, the pump 11-10 supplies
wash water 11-7' from the wash water tank 11-9 to the wash water
recovering apparatus 12-21 via the tube 11-12. The wash water
recovering apparatus 12-21 removes metallic ions and foreign matter
from the wash water 11-7' to recover the wash water. The recovered
wash water is supplied to the nozzle 11-8 via a tube 11-13 and
reused as wash water 11-7. When necessary, the wash water
recovering apparatus 12-21 is replenished with a pure water
12-22.
FIG. 9 shows an example construction of the metallic ion extractor
12-5. The metallic ion extractor 12-5 is provided with a PH
regulating tank 12 and a chelate resin column 14. The wash water
11-7' in the wash water tank 11-9 that has been used for washing in
the plating section 1 of FIG. 7 is transferred via the tube 11-12
by the pump 11-10 and stored in the PH regulating tank 12. The PH
regulating tank 12 injects a corrective 11 into the wash water
11-7' to regulate the PH value of the same. After the PH value has
been regulated, a pump 13 transfers the wash water 11-7' to the
chelate resin column 14.
If the wash water 11-7' contains metallic ions such as Cu.sup.2+
ions when passing through the chelate resin column 14, a chemical
reaction will occur (R=Ca+Cu.sup.2+.fwdarw.R=Cu+Ca.sup.2+, where R
represents a functional group). In this reaction, Cu.sup.2+ ions
having a higher selectivity than Ca.sup.2+ ions are replaced with
Ca.sup.2+ ions from a Ca-type chelate resin in the chelate resin
column 14. Hence, the Cu.sup.2+ ions are adsorbed to the end of the
functional group, thereby eliminating Cu.sup.2+ ions from the wash
water. After the ions have been removed from the wash water 11-7'
in the chelate resin column 14 as described above, the wash water
11-7' is discharged as wastewater 12-18.
FIG. 10 shows an example construction of the wash water recovering
apparatus 12-21 in FIG. 8. The wash water recovering apparatus
12-21 includes a wastewater storage tank 21, a surface-active agent
column 22, an ultraviolet disinfecting column 23, an anion exchange
resin column 24, and a cation exchange resin column 25. After being
used for washing, the wash water 11-7' is transferred from the wash
water tank 11-9 shown in FIG. 8 by the pump 11-10 via the tube
11-12 and is stored in the wastewater storage tank 21.
A pump 26 feeds the wash water 11-7' from the wastewater storage
tank 21 through a filter 27 to remove any foreign matter. Next, the
wash water 11-7' passes through the surface-active agent column 22
in which organically added decomposed matter and foreign matter are
adsorbed and removed. Next, the wash water 11-7' passes through the
ultraviolet disinfecting column 23, which restrains the propagation
of various bacteria. As the wash water 11-7' passes through the
anion exchange resin column 24 and cation exchange resin column 25,
anions and cations are replaced with hydroxyl ions OH.sup.- and
hydrogen ions H.sup.+ to reproduce pure water. Next, the solution
passes through a filter 28 to remove any foreign matter. The
recovered pure water is then supplied to the nozzle 11-8 via a
three-way valve 29 and the tube 11-13. When necessary, the
wastewater storage tank 21 is replenished with a pure water 30
supplied via a shutoff valve 31.
FIG. 11 shows an example construction of the plating solution
recovering apparatus 12-4 shown in FIG. 8. The plating solution
recovering apparatus 12-4 comprises a surface-active agent column
41, a surface-active agent column 42, a plating solution recovering
tank 43, an additive solution tank 44, an additive solution tank
45, a copper sulfate solution tank 46, a sulfuric acid tank 47, and
a hydrochloric acid tank 48. The plating solution 11-1 containing
foreign matter and the like supplied from the regulating tank 12-1
shown in FIG. 7 or 8 passes through a filter 49 to remove any solid
particles. Next, the plating solution 11-1 passes through the
surface-active agent column 41 and surface-active agent column 42
to remove foreign matter such as decomposed matter from the organic
additives. Here, two surface-active agent columns (41 and 42)
having different properties are provided because the foreign matter
and decomposed matter from the organic additives have both high and
low molecular weight. Therefore, it is necessary to provide plural
type surface-active agent columns in order to adsorb the foreign
matter of different molecular weights effectively.
Next, the plating solution 11-1 is stored in the plating liquid
recovering tank 43. Into the plating solution recovering tank 43, a
first additive 50 is supplied by pump 55 from the additive solution
tank 44, a second additive 51 is supplied by pump 56 from the
additive solution tank 45, a copper sulfate solution 52 is supplied
by pump 57 from the copper sulfate solution tank 46, a sulfuric
acid solution 53 is supplied by pump 58 from the sulfuric acid tank
47, and a hydrochloric acid solution 54 is supplied by pump 59 from
the hydrochloric acid tank 48.
The above-described solutions are supplied in order to add
appropriate amounts of components to the plating solution. The
highly concentrated copper sulfate solution 52 is added to achieve
an appropriate concentration of copper ions. The sulfuric acid
solution 53 and hydrochloric acid solution 54 are added to regulate
the hydrogen ion index (PH value) and the concentration of chlorine
ions. The organic first additive 50 and second additive 51 are
added to regulate the plating solution 11-1. After the plating
solution 11-1 has been regulated, the pump 12-16 supplies the
plating solution 11-1 to the regulating tank 12-1 via the filter
12-17. In addition, the plating liquid recovering tank 43 is
replenished with a pure water 61 supplied via a shutoff valve 60
when needed.
In the plating apparatus having the construction shown in FIGS. 7
and 8, the first room in which the plating section 1 is installed
is a clean room. However, the first room is not limited to being a
clean room, but can be any room or area having high cleanliness,
such as a clean booth, clean bench, or clean box.
In the construction of the plating apparatus described in FIGS. 7
and 8, the power supply 11-5 is disposed in the plating section 1,
which in turn is installed in the first room. However, it is also
possible to provide the power supply 11-5 in the second room in
which the control section 2 is installed, such that the power
supply 11-5 supplies electricity from the second room. With this
configuration, maintenance operations on the power supply 11-5 can
also be performed in the second room housing the control section 2.
If the power supply 11-5 is an accumulator (storage battery), in
particular, it is desirable to perform the dirty maintenance work
required for the accumulator in the second room.
In the construction described in FIGS. 7 and 8, one plating section
1 is provided with one control section 2. However, it is also
possible to configure the plating apparatus with one control
section 2 for a plurality of plating sections 1. In this case, the
plurality of plating sections 1 is installed in the first room,
while the single control section 2 is installed in the second room,
and the one control section 2 controls the plurality of plating
sections 1.
While the description of some apparatus were omitted from the
construction described in FIGS. 7 and 8, mechanisms that require
maintenance such as a flow meter for measuring the flow of solution
including plating solution or electrolytic solution, a pressure
gauge for measuring pressure, and a temperature gauge are installed
in the second room having a low degree of cleanliness. Accordingly,
there is no fear of contaminating the first room having a high
level of cleanliness by performing such maintenance in that
room.
Although the object of plating is described as the substrate 11-4,
such as a semiconductor wafer, the plating object is not limited to
a substrate.
In summary, the present invention has the following superior
effects. (1) The present invention provides functions for
processing wasted wash water and recovering used plating solution,
as well as a special self-determining function for processing
plating solution and solution including plating solution.
Therefore, these processes are carried out efficiently. (2) Most
maintenance work on the plating apparatus can be performed in the
second room housing the control section. Thereby, it improves the
efficiency of maintenance work and prevents contamination of the
first room housing the plating section, which must maintain a high
level of cleanliness.
INDUSTRIAL APPLICABILITY
The present invention relates to a plating apparatus for forming
metal plating on a substrate, such as a semiconductor wafer.
Therefore, this plating apparatus applies to industrial fields such
as semiconductor fabrication that require a high degree of
cleanliness and precision plating.
* * * * *