U.S. patent application number 11/882177 was filed with the patent office on 2008-02-07 for electrochemical processing apparatus and method of processing a semiconductor device.
This patent application is currently assigned to NEC ELECTRONICS CORPORATION. Invention is credited to Koji Arita, Tetsuya Kurokawa, Kaori Noda.
Application Number | 20080029402 11/882177 |
Document ID | / |
Family ID | 39028088 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080029402 |
Kind Code |
A1 |
Kurokawa; Tetsuya ; et
al. |
February 7, 2008 |
Electrochemical processing apparatus and method of processing a
semiconductor device
Abstract
An electrochemical processing apparatus is provided, in which a
substrate and an anode placed in a chamber are partitioned into a
cathode region including the substrate and an anode region
including the anode by placing a multi-layered structure of a
filtration film and a cation exchange film so that the filtration
film is positioned on the substrate side. A plating solution
containing additives is introduced into the cathode region, whereby
a substrate is plated.
Inventors: |
Kurokawa; Tetsuya;
(Kawasaki, JP) ; Arita; Koji; (Kawasaki, JP)
; Noda; Kaori; (Kawasaki, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET, 2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
NEC ELECTRONICS CORPORATION
KAWASAKI
JP
|
Family ID: |
39028088 |
Appl. No.: |
11/882177 |
Filed: |
July 31, 2007 |
Current U.S.
Class: |
205/157 ;
204/194; 257/E21.175 |
Current CPC
Class: |
H01L 21/2885 20130101;
C25D 17/002 20130101; C25D 7/123 20130101; C25D 21/22 20130101;
C25D 17/001 20130101 |
Class at
Publication: |
205/157 ;
204/194 |
International
Class: |
C25D 7/12 20060101
C25D007/12; C25D 17/00 20060101 C25D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2006 |
JP |
2006-214895 |
Claims
1. An electrochemical processing apparatus, comprising: a chamber;
and a multi-layered structure provided to partition the chamber
into an anode region and a cathode region, said structure including
a filtration film facing said cathode region and a cation exchange
film facing said anode region.
2. The apparatus according to claim 1, wherein the filtration film
and the cation exchange film are provided in contact with each
other.
3. The apparatus according to claim 1, wherein the filtration film
has a hole diameter of 0.5 .mu.m or less.
4. The apparatus according to claim 1, wherein: the chamber has a
plating solution containing a leveler, an accelerator, and a
suppressor introduced into the cathode region; and the
multi-layered structure is configured to suppress transmission of
the accelerator, the leveler, and the suppressor.
5. The apparatus according to claim 1, wherein the anode is made of
copper.
6. The apparatus according to claim 5, wherein the multi-layered
structure is configured to allow transmission of copper ions.
7. A chamber including an anode and a cathode, a filtration film
provided in the chamber between the anode and the cathode, and a
cation exchange film provided in the chamber between the
8. The chamber according to claim 7, the cathode is a filtration
film and the anode. semiconductor wafer.
9. A method of plating a conductive film by use of an
electrochemical processing apparatus which includes a chamber with
an anode, a cathode, a filtration film between the anode and the
cathode and a cation exchange film between the filtration film and
the anode, the method comprising plating a semiconductor substrate
into the chamber as the cathode, applying an electric power between
the anode and the semiconductor substrate to plate a conductive
film on the semiconductor substrate.
10. The method according to claim 9, further comprising introducing
a plating solution containing a leveler, an accelerator, and a
suppressor into the chamber.
11. The method according to claim 10, wherein the anode comprising
a copper so that a copper film is plated on the semiconductor
substrate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electrochemical
processing apparatus and a method of processing a semiconductor
device.
[0003] 2. Description of the Related Art
[0004] Electrochemical processing is generally used for embedding
recesses such as trenches and through holes formed on or over a
semiconductor substrate with a metal material such as copper to
form wiring and vias. Conventionally, such electrochemical
processing has problems that particles are generated on an anode
side in a plating solution, and additives such as an accelerator, a
leveler, and a suppressor are decomposed on the anode. In order to
prevent such problems, there are some technologies that an ion
exchange film or a filtration film separating between an anode and
a substrate is used in an electrochemical processing apparatus.
[0005] JP 2003-73889 A describes the configuration in which a
chamber is partitioned into a cathode region and an anode region
with an anion exchange film when copper is electro-plated on or
over a semiconductor wafer. This configuration is considered to be
capable of preventing particles from adhering to the semiconductor
wafer.
[0006] JP 2005-133187 A describes a plating technique that an ion
exchange film and a surface of a substrate to be plated are brought
close or contacted with each other and moved relatively. Since
plating on an upper portion of a wiring pattern is suppressed to be
low plating speed, this is considered to be capable of forming a
flat electro-plated film.
[0007] JP 2000-192298 A describes the configuration in which a
partition film made of a porous filtration film or a cation
exchange film is placed between anode electrode plate and a
substrate to be plated, whereby a chamber body is partitioned into
an anode chamber and a cathode chamber. This prevents additives in
a plating solution from coming into contact with the surface of an
anode electrode plate to be decomposed, thereby suppressing a
plated surface from becoming coarse due to the shortage of
additives, and can remove oxygen gas generated on the surface of
the anode electrode plate rapidly, thereby forming an uniform metal
electro-plated film.
[0008] JP 2001-49498 A describes the configuration in which a
substrate to be plated and an anode electrode are partitioned by
placing an ion exchange resin or a porous filtration film
therebetween. This configuration is considered to be capable of
preventing air bubbles from adhering to a plated surface of the
substrate to be plated.
[0009] However, the inventors of the present invention found that
there are the following problems in performing plating with the use
of these techniques.
[0010] A cation exchange film that selectively transmits only
cations is generally composed of a sulfonic group or the like, and
the surface thereof is negatively charged. Therefore, in the case
where a cation exchange film is provided between an anode and a
substrate, when additives are neutral or negatively charged, the
cation exchange film can suppress the additives from being
transmitted. However, in the case where the additives are
positively charged, the additives are likely to adsorb to the
cation exchange film. In general, when a leveler is positively
charged, and a cation exchange film is used, the consumption rate
of the leveler becomes high.
[0011] Furthermore, in the case where a filtration film is provided
between an anode and a substrate, when a filtration diameter of the
filtration film is set to be too minute, the transmission of ions
that are required to be transmitted between an anode side and a
substrate side is also prevented. Therefore, the filtration
diameter cannot be set to be so minute. For example, in the case of
using a dissoluble copper anode as an anode, if copper ions do not
move smoothly between the anode and the substrate, the use
efficiency of the copper ions from anode decreases. Therefore, it
is necessary to increase the filtration diameter of the filtration
film to such a degree that the copper ions can be transmitted.
Therefore, the transmission of the additives with a small molecular
weight such as an accelerator cannot be suppressed.
[0012] In the above-mentioned conventional technique, since only
either one of a cation exchange film or a filtration film (or an
anion exchange film) is provided between an anode and a substrate,
the consumption of additives in a plating solution cannot be
reduced. Furthermore, the additives are transmitted to the anode
side, come into contact with the anode to be decomposed, and are
accumulated in the plating solution as impurities, which cause the
defects in an electro-plated film.
SUMMARY
[0013] According to the present invention, there is provided an
electrochemical processing apparatus, including:
[0014] a chamber; and
[0015] a multi-layered structure including a filtration film and a
cation exchange film,
[0016] the multi-layered structure being placed between a substrate
and an anode that are placed in the chamber so that the filtration
film is positioned on the substrate side and partitioning the
chamber into a cathode region including the substrate and an anode
region including the anode.
[0017] According to the present invention, there is provided a
method of processing a semiconductor device, including an
electrochemical processing step of plating a substrate in a state
where a multi-layered structure including a filtration film and a
cation exchange film is placed between a substrate and an anode
that are placed in a chamber so that the filtration film is
positioned on the substrate side, and the chamber is partitioned
into a cathode region including the substrate and an anode region
including the anode. A plating solution containing additives is
used in the electrochemical processing step.
[0018] Herein, the filtration film can be a nonpolar filtration
film having no polarity. Furthermore, the filtration film can be
configured so as to have a porous structure and suppress the
transmission of molecules with a large molecular weight (molecular
diameter) by adjusting a hole diameter.
[0019] With such a configuration, for example, even in the case
where a leveler, an accelerator, and a suppressor that are
additives are present in a cathode region, the leveler can be
prevented from adsorbing to a cation exchange film, and the
additives with a small molecular weight can be prevented from being
transmitted to an anode side. This can reduce the consumption of
the additives.
[0020] The anode (anode electrode plate) can also be composed of,
for example, a dissoluble copper anode, or an insoluble anode. In
the case where the anode is composed of a copper anode, a
multi-layered film can be configured so as to transmit copper
ions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other objects, advantages and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings, in
which:
[0022] FIG. 1 is a cross-sectional view illustrating a
configuration of an electrochemical processing apparatus of the
present invention;
[0023] FIG. 2 is a plan view in which a multi-layered structure
included in the electrochemical processing apparatus of the present
invention is seen from the filtration film side;
[0024] FIG. 3 is a view illustrating the consumption of a leveler
in an example;
[0025] FIG. 4 is a diagram illustrating the consumption of an
accelerator in the example;
[0026] FIG. 5 is a diagram illustrating the consumption of a
suppressor in the example; and
[0027] FIGS. 6A and 6B are cross-sectional views illustrating a
process of a semiconductor device of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] The invention will be now described herein with reference to
illustrative embodiments. Those skilled in the art will recognize
that many alternative embodiments can be accomplished using the
teachings of the present invention and that the invention is not
limited to the embodiments illustrated for explanatory
purposes.
[0029] FIG. 1 is a cross-sectional view illustrating a
configuration of an electrochemical processing apparatus 200 in the
present embodiment.
[0030] The electrochemical processing apparatus 200 includes a
chamber 201, and an anode 220 placed in the chamber 201. In the
present embodiment, the anode 220 can be composed of a dissoluble
copper anode. In the chamber 201, a plating solution 202 is
contained. The plating solution 202 is composed of, for example,
copper sulfate aqueous solution. In addition, the electrochemical
processing apparatus 200 has a substrate support (not shown) on
which a substrate 100 is to be placed, and the substrate 100 is
placed on the substrate support.
[0031] The electrochemical processing apparatus 200 includes a
multi-layered structure 204 of a filtration film 210 and a cation
exchange film 208 placed between the substrate 100 and the anode
220. The multi-layered structure 204 is placed so that the
filtration film 210 is positioned on the substrate 100 side. The
chamber 201 is partitioned into a cathode region 202a including the
substrate 100 and an anode region 202b including the anode 220 by
the multi-layered structure 204. Furthermore, the electrochemical
processing apparatus 200 includes a diffusion plate 214 placed
between the multi-layered structure 204 and the substrate 100. The
diffusion plate 214 is placed for the purpose of making the flow of
the plating solution 202 uniform in the vicinity of the substrate
100. It should be noted that the diffusion plate 214 is configured
so as to have a sufficiently large hole diameter and to transmit
components of the plating solution 202.
[0032] In the cathode region 202a, levelers, accelerators, and
suppressors are introduced as additives into the plating solution
202.
[0033] In the present embodiment, as the levelers, for example, a
positively charged material having a molecular weight of 2000 to
3000 can be used. As such a material, for example, a cationic amine
polymer can be used.
[0034] In the present embodiment, as the accelerators, for example,
a negatively charged material having a molecular weight of 500 or
less and a disulfide bond can be used. As such a material, the one
represented by the general formula:
SO.sub.3--R.sub.1--S--S--R.sub.2--SO.sub.3-- (herein, R.sub.1 and
R.sub.2 are respectively hydrocarbon chains independently) can be
used.
[0035] In the present embodiment, as the suppressors, for example,
a material having a molecular weight of 2000 to 3000 and no
polarity can be used. As such a material, for example, polyethylene
glycol can be used.
[0036] The multi-layered structure 204 is configured so as to
suppress the transmission of levelers, accelerators, and
suppressors. Furthermore, in the present embodiment, the
multi-layered structure 204 is configured so as to transmit copper
ions. The filtration film 210 has minute holes, and transmits
molecules with a size smaller than the hole diameter and suppresses
the transmission of molecules with a size larger than the hole
diameter. The filtration film 210 is configured so as to have no
polarity and have a hole diameter of suppressing the transmission
of at least the levelers. In the present embodiment, the hole
diameter of the filtration film 210 can be set to be 0.5 .mu.m or
less. This can suppress the transmission of the levelers. On the
other hand, in order to transmit copper ions, the hole diameter of
the filtration film 210 can be set to be 0.01 .mu.m or more. As the
filtration film 210, for example, polypropylene can be used.
[0037] The cation exchange film 208 selectively transmits only
cations. As the cation exchange film 208, for example, polyacrylic
resin having a sulfonic group can be used.
[0038] In the present embodiment, the multi-layered structure 204
includes a multi-layered film 206 in which the filtration film 210
and the cation exchange film 208 are provided in contact with each
other, and a support plate 212 supporting the multi-layered film
206. By using the multi-layered film 206, bubbles of air or the
like can be prevented from entering between the filtration film 210
and the cation exchange film 208, and the flow of the plating
solution in the chamber 201 can be regulated easily.
[0039] FIG. 2 is a plan view in which the multi-layered structure
204 is seen from the filtration film 210 side. The chamber 201 is
configured in a cylindrical shape (not shown). The multi-layered
structure 204 is configured in a size equal to that of the
cross-section of the chamber 201, and partitions the chamber 201
into the cathode region 202a and the anode region 202b. The
multi-layered structure 204 can have any configuration as long as
levelers, accelerators, and suppressors introduced in the cathode
region 202a are not transmitted to the anode region 202b. As other
examples, a partition wall that partially partitions the plating
solution 202 and the substrate 100 is provided, and the
multi-layered structure 204 may be placed in an open portion which
is not partitioned by the partition wall. Herein, the support plate
212 is composed of, for example, a plastic material, and has a
framework reinforcing the multi-layered film 206.
[0040] Next, the function of the multi-layered structure 204
configured as described above will be described.
[0041] In the multi-layered structure 204, the filtration film 210
is provided on the cathode region 202a side. Therefore, in the case
where levelers, accelerators, and suppressors are introduced in the
cathode region 202a, first, the transmission of levelers and
suppressors having a large molecular weight are suppressed by the
filtration film 210. This can prevent levelers and suppressors from
moving to the anode region 202b, thereby reducing the consumption
thereof. Furthermore, the positively charged levelers can be
prevented from coming into contact with the cation exchange film
208, so the consumption of levelers can be reduced more. On the
other hand, even when accelerators having a small molecular weight
are transmitted through the filtration film 210, the cation
exchange film 208 can prevent accelerators from moving to the anode
region 202b. Consequently, even when the hole diameter of the
filtration film 210 is set in such a degree as to transmit
accelerators, the consumption of accelerators can be reduced.
[0042] Next, the procedure of processing a semiconductor device
using the electrochemical processing apparatus 200 in the present
embodiment will be described with reference to FIG. 6. A
semiconductor device 300 is formed on a semiconductor substrate
302, including transistors and the like, an insulating film 304
formed over the transistors, and an insulating film 306 formed over
the insulating film 304. Wiring and vias are formed in the
insulating films 304 and 306.
[0043] In the semiconductor device 300 thus configured,
interconnect features (trenches) are formed on the insulating film
306. Herein, as shown, in the insulating film 306, interconnect
feature 308, interconnect feature 310, interconnect feature 312,
interconnect feature 314, interconnect feature 316, interconnect
feature 318, and interconnect feature 320 are formed (FIG. 6A).
[0044] The procedure of burying such trenches with a wiring
material will be shown below. First, a barrier metal film is formed
in the trenches of the insulating film 306. TaN/Ta is usually used
as a barrier metal of copper interconnects. Then a seed film for
plating is formed on the barrier film. Herein, a seed film is made
of a copper film formed by CVD or the like.
[0045] Then, the substrate with the seed film formed thereon is
plated using the electrochemical processing apparatus 200.
Consequently, an electro-plated film 332 is formed in the trenches.
Herein, the electro-plated film 332 is, for example, made of a
copper film (FIG. 6B). The defects caused by a decomposition
product of the additives are suppressed by using the
electrochemical processing apparatus 200 in the present
embodiment.
EXAMPLE
[0046] In the same way as in the configuration of the apparatus
illustrated in FIG. 1, using an apparatus in which the
multi-layered structure 204 is placed between the substrate 100 and
the anode 220 (in the electrochemical processing apparatus), the
consumption of a leveler, a accelerator, and a suppressor during
plating were checked, respectively. A cation amine polymer with a
molecular weight of 2500 was used as the leveler,
bis(3-sulfopropyl) disulfide with a molecular weight of 310 was
used as the accelerator, and polyethylene glycol with a molecular
weight of 2200 was used as the suppressor. As the cation exchange
film, polyacrylic resin having a sulfonic group was used, and as
the filtration film, polypropylene was used. An experiment was
conducted every day for 30 days. For comparison, the consumption of
the leveler, the accelerator, and the suppressor were respectively
checked in the case of only the filtration film, only the cation
exchange film, and the absence of the filtration film and the
cation exchange film.
[0047] FIGS. 3 to 5 illustrate the results. The conditions are as
follows.
(1) Multi-layered structure (filtration film+cation exchange film:
multi-layered structure 204)
(2) Only filtration film
(3) Only cation exchange film
(4) Absence of filtration film and cation exchange film
[0048] FIG. 3 illustrates the consumption of the leveler. Herein,
the vertical axis represents the consumption of the leveler
normalized with the case (1) using the multi-layered structure
being 1. In any of the cases (1) to (3), the consumption of the
leveler was reduced compared with the case (4) without using a
film. However, in the case (3) using only the cation exchange film,
the consumption of the leveler was increased about twice that of
the case (1) using the multi-layered film. In the case (2) using
only the filtration film, the consumption of the leveler was
increased slightly compared with the case (1) using the
multi-layered film; however, no large change was found. In any
case, there was no change in film characteristics even after the
elapse of 30 days.
[0049] FIG. 4 illustrates the consumption of the accelerator.
Herein, the vertical axis represents the consumption of the
accelerator normalized with the case (1) using the multi-layered
film being 1. In any of the cases (1) to (3), the consumption of
the accelerator was reduced compared with the case (4) without
using a film. However, in the case (2) using only the filtration
film, the consumption of the accelerator was increased by about 1.5
times that of the case (1) using the multi-layered film. In the
case (3) using only the cation exchange film, the consumption of
the accelerator was increased slightly compared with the case (1)
using the multi-layered film; however, no large change was found.
In any case, there was no change in film characteristics even after
the elapse of 30 days.
[0050] FIG. 5 illustrates the consumption of the suppressor. Herein
the vertical axis represents the consumption of the suppressor
normalized with the case (1) using the multi-layered film being 1.
In any of the cases (1) to (3), the consumption of the suppressor
was reduced compared with the case (4) without using a film. In the
case (2) using only the filtration film and the case (3) using only
the cation exchange film, the consumption of the accelerator was
increased slightly compared with the case (1) using the
multi-layered film; however, no large change was found. In any of
the cases, there was no change in film characteristics even after
the elapse of 30 days.
[0051] As described above, by using the multi-layered structure
204, the consumption of all the three additives: the leveler, the
accelerator, and the suppressor were reduced simultaneously.
[0052] The embodiment of the present invention has been described
with reference to the drawings. However, it is represented merely
for an illustrative purpose, and other various configurations can
also be adopted.
[0053] In the embodiment, the case where the anode 220 is a copper
anode has been illustrated. However, as the anode 220, an insoluble
anode may be used. Even in this case, the multi-layered structure
204 can be configured in the same way as in the above; however, it
may be configured so as not to transmit copper ions, for
example.
[0054] Furthermore, in the above-mentioned embodiment, copper
plating has been illustrated, in which the plating solution
contains copper ions. However, the present invention can be applied
to other various plating. For example, the present invention can be
applied to the plating in which bumps of a semiconductor device are
formed using nickel or the like. Even in this case, as an anode,
any of a dissoluble or insoluble anode may be used.
* * * * *