U.S. patent application number 11/653953 was filed with the patent office on 2008-03-13 for polishing apparatus and manufacturing method of an electronic apparatus.
This patent application is currently assigned to FUJITSU LIMITED. Invention is credited to Naoki Idani.
Application Number | 20080064308 11/653953 |
Document ID | / |
Family ID | 39170302 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080064308 |
Kind Code |
A1 |
Idani; Naoki |
March 13, 2008 |
Polishing apparatus and manufacturing method of an electronic
apparatus
Abstract
A polishing apparatus that polishes a substrate to be processed
includes a rotary polishing table carrying a polishing pad on a
surface thereof, and a polishing head that urges the substrate to
be processed against the polishing pad while rotating the substrate
to be processed, wherein the polishing head holds the substrate to
be processed by a retainer ring, the retainer ring includes: a
resin ring formed of a resin and contacted with the polishing pad;
and an upper part ring that holds the resin ring, at least first
and second patterns of convex shape or concave shape are formed on
a junction surface of the upper part ring where the upper part ring
is contacted with the resin ring, at least third and fourth
patterns of concave shape or convex shape are formed on a junction
surface of the resin ring where the resin ring makes contact with
the upper electrode, in a manner complementary to the patterns of
the convex shape or concave shape formed on the junction surface of
the upper electrode.
Inventors: |
Idani; Naoki; (Kawasaki,
JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW, SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
FUJITSU LIMITED
Kawasaki
JP
|
Family ID: |
39170302 |
Appl. No.: |
11/653953 |
Filed: |
January 17, 2007 |
Current U.S.
Class: |
451/285 |
Current CPC
Class: |
B24B 37/32 20130101 |
Class at
Publication: |
451/285 |
International
Class: |
B24B 29/00 20060101
B24B029/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 8, 2006 |
JP |
2006-244305 |
Claims
1. A polishing apparatus that polishes a substrate to be processed,
comprising: a rotary polishing table carrying a polishing pad on a
surface thereof; and a polishing head that urges said substrate to
be processed against said polishing pad while rotating said
substrate to be processed, wherein said polishing head holds said
substrate to be processed by a retainer ring, said retainer ring
comprising: a resin ring formed of a resin and contacted with said
polishing pad; and an upper part ring that holds said resin ring,
at least first and second patterns of convex shape or concave shape
being formed on a junction surface of said upper part ring where
said upper part ring is contacted with said resin ring, at least
third and fourth patterns of concave shape or convex shape being
formed on a junction surface of said resin ring where said resin
ring makes contact with said upper electrode, in a manner
complementary to the said patterns of said convex shape or concave
shape formed on said junction surface of said upper electrode.
2. The polishing apparatus as claimed in claim 1, wherein said
first and second patterns are formed on said junction surface of
said upper ring respectively in a circumferential direction and in
a radial direction, said third and fourth patterns are formed on
said junction surface of said resin ring respectively in said
circumferential direction and said radial direction.
3. The polishing apparatus as claimed in claim 2, wherein said
first pattern is formed on said junction surface of said upper ring
so as to go around continuously along said upper ring, and wherein
said third pattern is formed on said junction surface of said resin
ring so as to go around contiguously along said resin ring.
4. The polishing apparatus as claimed in claim 1, wherein said
first and second patterns form plural pattern elements each
extending on said junction surface of said upper ring in a radial
direction, and wherein said third and fourth patterns form plural
pattern elements each extending on said junction surface of said
resin ring in a radial direction.
5. The polishing apparatus as claimed in claim 1, wherein said
first and second patterns form isolated patterns on said junction
surface of said upper part ring, and wherein said third and fourth
patterns form isolated patterns on said junction surface of said
resin ring.
6. The polishing apparatus as claimed in claim 1, wherein said
resin ring and said upper part ring are connected with each other
by adhering said respective junction surfaces by an adhesive.
7. The polishing apparatus as claimed in claim 1, wherein said
resin ring and said upper part ring are connected with each other
by screws.
8. A method for fabricating a semiconductor device, comprising a
step of polishing a film formed on a substrate to be processed by
using a polishing apparatus, said polishing apparatus comprising: a
rotary polishing table carrying a polishing pad on a surface
thereof; and a polishing head that urges said substrate to be
processed against said polishing pad while rotating said substrate
to be processed, wherein said polishing head holds said substrate
to be processed by a retainer ring, said retainer ring comprising:
a resin ring formed of a resin and contacted with said polishing
pad; and an upper part ring that holds said resin ring, at least
first and second patterns of convex shape or concave shape being
formed on a junction surface of said upper part ring where said
upper part ring is contacted with said resin ring, at least third
and fourth patterns of concave shape or convex shape being formed
on a junction surface of said resin ring where said resin ring
makes contact with said upper electrode, in a manner complementary
to the said patterns of said convex shape or concave shape formed
on said junction surface of said upper electrode.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is based on Japanese priority
application No.2006-244305 filed on Sep. 8, 2006, the entire
contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to manufacturing of
electronic apparatuses and more particularly to a chemical
mechanical polishing apparatus used for manufacturing of such an
electronic apparatus.
[0003] The technology of chemical mechanical polishing (CMP) has
been used extensively for forming Cu multilayer interconnection
structure by a damascene process or dual damascene process. On the
other hand, because of the capability of providing near ideal flat
surface in the processed surface, chemical mechanical polishing
process provides a particularly advantageous effect when used with
a photolithographic process that includes a high resolution
exposure process and hence characterized by shallow focal depth.
Thus, chemical mechanical polishing process is used extensively in
these days as the technology indispensable for the production of
semiconductor integrated circuit devices of high integration
density or for the production of high resolution display
devices.
Patent Reference 1
[0004] Japanese Laid-Open Patent Application 2005-34959 Official
Gazette
Patent Reference 2
[0005] Japanese Laid-Open Patent Application 2000-301452 Official
Gazette
SUMMARY OF THE INVENTION
[0006] FIG. 1 shows the construction of a polishing apparatus 100
according to a related art of the present invention.
[0007] Referring to FIG. 1, the polishing apparatus 100 has a
construction of using a polishing pad 101 fixed upon a rotating
polishing table 102, and a substrate 103 such as a wafer to be
processed is urged against the polishing pad 101 covering the
surface of the rotating polishing table 102 by using a polishing
head 104 that urges the substrate 103 against the polishing pad 101
with a predetermined pressure while rotating the substrate 103.
[0008] Further, with the polishing apparatus 100 of FIG. 1, slurry
106 is supplied upon the polishing pad 101 from a supply nozzle 105
in the form of liquid, wherein the slurry causes a chemical
reaction with the surface of the substrate to be processed at the
part where the polishing pad 101 makes a contact with the substrate
103. Thereby, the reaction product formed as a result of the
reaction is removed by the mechanical action of the abrasive
particles contained in the slurry or by the mechanical action of
the polishing pad. There can also be a case with such a chemical
mechanical polishing process in which the slurry does not
containing abrasive particles.
[0009] Further, in order to maintain the fresh surface state of the
polishing pad 101, there is provided a roughening device 107 on the
polishing table 102 at a location different from the location where
the polishing head 104 is provided.
[0010] FIG. 2 shows the details of the polishing head 104.
[0011] Referring to FIG. 2, the polishing head 104 includes a
membrane 121 that urges the substrate 103 to be processed against
the polishing pad 101 with pressure, wherein the membrane 121 and
the substrate 103 are held by a retainer ring 122. The retainer
ring 122 not only holds the membrane 121 and the substrate 103 but
also functions to improve the in-plane distribution of polishing as
it is urged against the polishing pad 101.
[0012] FIG. 3 shows the details of the retainer ring 122 of the
FIG. 2.
[0013] Referring to FIG. 3, the retainer ring 122 is formed of an
upper part ring 122a of a metal member such as stainless steel and
a resin ring 122b formed under the upper part ring 122a and is
urged against the polishing pad 101. It should be noted that the
resin ring 122b is adhered to the upper part ring 122a by an
adhesives at a junction surface 122c.
[0014] Meanwhile, with recent chemical mechanical polishing
apparatuses, there is an increasing opportunity of polishing a
wafer of 30 cm diameter in the prospect of improved productivity of
electronic apparatuses. However, in the case of polishing a wafer
of such a large diameter, it was discovered that there occurs, in
some cases, a rupture at the junction surface 122c.
[0015] Further, in the case of the retainer ring of the type in
which the resin ring 122b and the upper part ring 122a are fixed
with each other by way of screws, too, it was discovered that such
a rupture occurs at the junction surface in the vicinity of the
screwed parts.
[0016] When there occurs a rupture at such a junction surface
between the resin ring 122b and the upper part ring 122a, not only
the polishing apparatus is damaged, but there is also caused a
deterioration of yield in the polishing process by the fragments
falling upon the polishing pad 101.
[0017] It is believed that such a rupture between the resin ring
122b and the upper part ring 122a is caused as a result of increase
of the stress applied to the resin ring 122b as a result of
increase of friction between the polishing pad and the retainer
ring particularly at the peripheral part of the retainer ring,
while such increase of friction becomes conspicuous when the
diameter of the substrate 103 to be processed is increased.
[0018] Thereupon, it may be conceivable that such a rupture between
the resin ring 122b and the upper part ring 122a may be avoided by
forming the whole retainer ring 122 by a resin. However, even in
such a case of the retainer ring of unitary resin construction,
there is a need of connecting the resin ring to a metal member
constituting a part of the polishing head 104 at some location, and
thus, this problem of rupture at the connection part cannot be
avoided in any of the case of achieving the connection by an
adhesive and the case of achieving the connection by screws.
[0019] The present invention proposes a polishing apparatus that
polishes a substrate to be processed, comprising:
[0020] a rotary polishing table carrying a polishing pad on a
surface thereof; and
[0021] a polishing head that urges said substrate to be processed
against said polishing pad while rotating said substrate to be
processed,
[0022] wherein said polishing head holds said substrate to be
processed by a retainer ring,
[0023] said retainer ring comprising: a resin ring formed of a
resin and contacted with said polishing pad; and
an upper part ring that holds said resin ring,
[0024] at least first and second patterns of convex shape or
concave shape being formed on a junction surface of said upper part
ring where said upper part ring is contacted with said resin
ring,
[0025] at least third and fourth patterns of concave shape or
convex shape being formed on a junction surface of said resin ring
where said resin ring makes contact with said upper electrode, in a
manner complementary to the said patterns of said convex shape or
concave shape formed on said junction surface of said upper
electrode.
[0026] Further, the present invention provides a manufacturing
method of an electronic apparatus using such a polishing
apparatus.
[0027] Thus, by forming at least the first and second patterns of
convex or concave shape on the junction surface of the upper ring
and further by forming at least the third and fourth patterns of
convex or concave shape on the junction surface of the resin ring
in complementary manner to the first and second patterns at the
time of joining the upper ring and the resin ring constituting the
retainer ring, it becomes possible to avoid damaging of the
junction part between the resin ring and the upper ring, even when
a large stress is applied to the resin ring, and it becomes
possible to conduct the desired polishing process efficiently and
with high yield.
[0028] Other objects and further features of the present invention
will become apparent from the following detailed description when
read in conjunction with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a diagram showing the construction of a polishing
apparatus according to a related art of the present invention;
[0030] FIG. 2 is a diagram showing the construction of a polishing
head used with the polishing apparatus of FIG. 1;
[0031] FIG. 3 is a diagram showing the construction of a retainer
ring used with the polishing head of FIG. 2;
[0032] FIG. 4 is a diagram showing the construction of a polishing
apparatus according to a first embodiment of the present
invention;
[0033] FIG. 5 is a diagram showing construction of a polishing head
used with the polishing apparatus of FIG. 4;
[0034] FIG. 6 is a diagram showing the construction of a retainer
ring used the polishing head of FIG. 5;
[0035] FIGS. 7A and 7B are diagrams showing the construction of an
upper part ring of the retainer ring of FIG. 6 respectively in a
plan view and cross-sectional view;
[0036] FIGS. 8A and 8B are diagrams showing the construction of a
resin ring of the retainer ring of FIG. 6 respectively in a plan
view and a cross-sectional view;
[0037] FIGS. 9A and 9B are diagrams showing a connection of the
upper part ring and the resin ring of FIGS. 7 and 8;
[0038] FIGS. 10A and 10B are diagrams showing a modification of the
retainer ring of FIG. 6;
[0039] FIGS. 11A and 11B are diagrams showing a different
modification of the retainer ring of FIG. 6;
[0040] FIGS. 12A and 12B are diagrams showing a connection of the
upper part ring and the resin ring of FIGS. 11A and 11B; and
[0041] FIGS. 13A-13D are diagrams showing the fabrication process
of a semiconductor device according to a second embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0042] FIG. 4 shows the construction of a polishing apparatus 10
according to a first embodiment of the present invention.
[0043] Referring to FIG. 1, the polishing apparatus 10 has a
construction in which a polishing pad 11 is fixed upon a rotating
polishing table 12, and a substrate 13 such as a wafer to be
processed is urged against the surface of the polishing table 12 by
a rotating polishing head 14 with a predetermined pressure.
[0044] Further, with the polishing apparatus 10 of FIG. 4, slurry
16 is supplied upon the polishing pad 11 from a supply nozzle 15 in
the form of liquid, wherein the slurry causes a chemical reaction
with the surface of the substrate to be processed at the part where
the polishing pad 11 makes a contact with the substrate 13 to be
processed. Thereby, the reaction product formed as a result of the
reaction is removed by the mechanical action of the abrasive
particles in the slurry or by the mechanical action of the
polishing pad 11. There can also be a case with such a chemical
mechanical polishing process in which slurry not containing
abrasive particles is used.
[0045] Further, in order to maintain the fresh surface state of the
polishing pad 11, there is provided a roughening device 17 on the
polishing table 12 at a location different from the location where
the polishing head 14 is provided.
[0046] Thus, with the polishing apparatus of FIG. 4, the polishing
head 14 is urged against the polishing pad 11 with a predetermined
pressure, and chemical mechanical polishing is applied to the
surface of the substrate 13 to be processed by dripping the slurry
16 while rotating the polishing head 14 and the polishing table 12
with respective rotational speeds.
[0047] With the polishing apparatus 10 of FIG. 4, not only the
silicon wafer of conventional diameter of 20 cm but also the
silicon wafer of larger diameter of 30 cm or more can be polished
as the substrate 13, and thus, the polishing head 14 can hold
thereon such a large diameter semiconductor wafer.
[0048] It should be noted that the above polishing condition, the
slurry and the polishing pad 11 can be changed as necessary
according to the nature of the film to be polished on the substrate
13.
[0049] FIG. 5 shows the details of the polishing head 14.
[0050] Referring to FIG. 5, the polishing head 14 includes a
membrane 21 that urges the substrate 13 to be processed against the
polishing pad 11, wherein the membrane 21 and the substrate 13 are
held by the retainer ring 22. It should be noted that the retainer
ring 22 not only holds the membrane 21 and the substrate 13 to be
processed thereon but it is possible to improve the in-plane
distribution of the polishing by being urged against the polishing
pad 11.
[0051] FIG. 6 shows the details of the retainer ring 22 of the FIG.
2.
[0052] Referring to FIG. 6, the retainer ring 22 is formed of an
upper part ring 22a of a metal member such as stainless steel and a
resin ring 22b of a resin such as polyether ether ketone (PEEK)
formed under the upper ring 22a such that the resin ring 22b is
urged against the polishing pad 11, wherein the resin ring 22b is
adhered to the upper part ring 22a by an adhesive at a junction
surface 22c.
[0053] FIG. 7A shows the upper part ring 22a as viewed from a lower
part in a plan view, while FIG. 7B shows the upper part ring 22a in
a cross-sectional view taken along a line A-A in FIG. 7A.
[0054] Referring to FIGS. 7A and 7B, the bottom surface 22c1 of the
upper part ring 22a forms one part of the junction surface 22c of
FIG. 6, wherein the bottom surface 22c1 is formed with a first
pattern 23a1 of a groove that goes around the upper part ring 22a
and a second pattern 23a2 of plural grooves 23a2 each formed in a
radial direction.
[0055] FIG. 8A shows the resin ring 22b in a plan view as viewed
from an upward direction, while FIG. 8B shows the resin ring 22b in
a cross-sectional view taken along a line B-B' of FIG. 8A.
[0056] Referring to FIGS. 8A and 8B, the upper surface 22c2 of the
resin ring 22b forms the other part of the junction surface 22c of
FIG. 6, wherein it can be seen that there are formed a first
pattern 23b1 of a convex part that goes around the resin ring 22b
and a second pattern 23b2 of plural convex parts each formed in a
radial direction.
[0057] The convex part 23b1 is formed with a complementary shape
corresponding to the groove 23a1, while the convex parts 23b2 are
formed with a correspondingly complementary shape of the grooves
23a2. Thus, in the case the upper part ring 22a and the resin ring
22b are coupled with each other as shown in FIG. 6, the convex part
23b1 engages with to the groove 23a1 as shown in the
cross-sectional view of FIG. 9A. Similarly, the convex parts 23b2
engage with respective, corresponding grooves 23a2 although not
illustrated.
[0058] Thus, by fixing the upper part ring 22a and the resin ring
22b with each other in such a mutually engaged state by an adhesive
in the retainer ring 22 of FIG. 6, the stress acting upon the resin
ring 22b is distributed to the convex parts 23b1 and 23b2 and to
the grooves 23a1 and 23a2, and the problem of the upper part ring
22a and resin ring 22b causing rupture at the junction surface 22c
is avoided.
[0059] Further, as shown in FIG. 9B, the stress acting upon the
resin ring 22b is distributed to the convex parts 23b1 and 23b2 and
further to the grooves 23a1 and 23a2 even in the case the coupling
between the upper part ring 22a and the resin ring 22b is achieved
by using screws 22d, and the problem of the upper part ring 22a and
the resin ring 22b causing rupture at the junction surface 22c is
avoided.
[0060] Furthermore, it is evident with the present embodiment that
similar effects are attained in the case the grooves and the convex
parts are formed oppositely to the upper ring 22a and the resin
ring 22b, and thus, for the case when the grooves 23a1 and 23a2 are
formed on the resin ring 22b and the convex parts 22b al and 22b 2
are formed on the upper part ring 22a.
[0061] FIGS. 10A and 10B show a modification of the first
embodiment.
[0062] Referring to FIGS. 10A and 10B, the present embodiment
eliminates the groove 23a1 extending in the circumferential
direction from the junction surface 22c1 and the convex part 23b1
extending in the circumference direction from the junction surface
22c2, and thus, there are formed only the grooves 23a2 and the
projections 23b2 extending in the radial direction.
[0063] Because the stress acting upon the junction surface 22c by
the friction acting to the polishing pad 11 works primarily in the
circumferential direction, it is possible to suppress the rupture
at the junction surface 22c effectively even in such a case in
which only the grooves 23a2 and the convex part 23b2 are formed to
extend in the radial direction respectively on the upper part ring
22a and the resin ring 22b.
[0064] FIGS. 11A and 11B show another modification of the present
embodiment.
[0065] Referring to FIGS. 11A and 11B, there are formed plural,
mutually independent depressions 23a on the junction surface 22c1
of the upper part ring 22a, and there are formed plural, mutually
independent convex part 23bs at the junction surface 22c2 of the
resin ring 22b in a complementary manner to the depressions
23a.
[0066] Thus, in the case of forming the retainer ring 22 by
coupling the upper part ring 22a and the resin ring 22b as shown in
FIG. 12A, the convex parts 23b are accepted by the corresponding
depressions 23a and the resin ring 22b is fixed firmly against the
upper part ring 22a in this state. Because the respective grooves
23a and the respective convex parts 23b form an isolated pattern in
the present embodiment, the position of the resin ring 22b is
determined against the upper part ring 22a in both the
circumferential direction and the radial direction, and occurrence
of rupture is suppressed at the junction surface 22c even in the
case a stress is applied in any of the circumferential direction
and the radial direction.
[0067] In the present modification, too, the upper part ring 22a
and the resin ring 22b may be fixed with each other by adhesives in
the state of FIG. 12A, while these can be fixed also by using
screws 23d as shown in FIG. 12B.
[0068] Further, with the present modification, it is also possible
to form the grooves 23a on the resin ring 22b and form the convex
parts 23b in the upper part ring 22a also in the present
modification.
Second Embodiment
[0069] FIGS. 13A-13D show a fabrication process of a semiconductor
device according to a second embodiment of the present invention
that uses the polishing apparatus 10 of FIG. 4.
[0070] Referring to FIG. 13A, a silicon substrate 41 of a silicon
wafer of 30 cm diameter is formed with an SiN pattern 43 via a
sacrificial oxide film 42 of a thermal oxide film, wherein there is
formed a device isolation trench 41A in the silicon substrate 41 so
as to define a predetermined device region 41B by a dry etching
process while using the SiN pattern 43 as a mask.
[0071] Next in step of FIG. 13B, there is formed an SiO.sub.2 film
44 on the structure of the FIG. 13A by a CVD process so as to fill
the device isolation trench 41A, and the silicon substrate 41, now
in the state in which the structure of the FIG. 13B is formed, is
held on the polishing head 14 of the polishing apparatus 10 as
explained with reference to FIGS. 4-6 in the step of FIG. 13C as
the substrate 13 to be processed, wherein the retainer ring 22 and
the membrane 21 explained with reference to FIGS. 7-8 are used for
holding the silicon substrate 41 on the polishing head 14.
[0072] Further, in the step of FIG. 14C, a commercially available
polishing pad marketed for example by Rodel Nitta Company under the
trade name IC1010 is used for the polishing pad 11, and polishing
of the SiO.sub.2 film 44 is conducted by using a commercially
available slurry marketed from Cabot Company under the trade name
SS25, for the slurry with 1:1 dilution. Thereby, the polishing is
conducted by rotating the polishing table 12 with a rotational
speed of 110 rpm and rotating the polishing head 14 with a
rotational speed of 98 rpm. During this polishing process, the
polishing head 14 is urged against the polishing pad 11 by using
the membrane 21 with a pressure of 280 gweight/cm.sup.2. Thereby,
polishing of the SiO.sub.2 film 44 is conducted until the SiN
pattern 43 is exposed. In this case, the retainer ring 22 is urged
against the polishing pad 11 with a pressure of about 700
g/cm.sup.2.
[0073] In the step of FIG. 13C, the SiN film 43 functions as a
polishing stopper, and a device isolation insulation film 44A of
SiO.sub.2 is formed in correspondence to the device isolation
trench 41A so as to define the device region 41B on the surface of
the substrate 41.
[0074] Next, in the step of FIG. 14C, the SiN film 43 and also the
sacrifice oxide film 42 are removed, and formation of the desired
semiconductor device is conducted on the device region 41B thus
exposed.
[0075] With the present embodiment, damaging of the retainer ring
22 is suppressed as a result of the use of the polishing apparatus
10, which in turn uses the retainer ring 22 explained previously,
for the chemical mechanical polishing process of FIG. 13C, even in
the case that the substrate 13 to be processed is a semiconductor
wafer of large diameter, and it becomes possible to improve the
efficiency and yield at the time of production of the semiconductor
device.
[0076] While the present invention has been explained for preferred
embodiments, the present invention is by no means limited to the
embodiments described heretofore, but various variations and
modifications may be made without departing from the scope of the
invention.
* * * * *