U.S. patent application number 10/014586 was filed with the patent office on 2003-06-19 for apparatus for chemical mechanical polishing.
Invention is credited to Chang, Hui-Chun, Huang, Chao-Yuan, Lin, Tsang Jung.
Application Number | 20030114076 10/014586 |
Document ID | / |
Family ID | 21766382 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030114076 |
Kind Code |
A1 |
Chang, Hui-Chun ; et
al. |
June 19, 2003 |
Apparatus for chemical mechanical polishing
Abstract
The present invention provides a chemical mechanical polishing
apparatus for polishing a wafer. The chemical mechanical polishing
apparatus comprises a platen, a polishing pad, a transparent
element (transparent window), a slurry providing system, and a
rotating carrier. The platen comprises a light source for
projecting a light and a light detector for detecting the light
reflected by the wafer. The polishing pad has a first opening on
the platen. The transparent element is detachably located on the
first opening to admit light. The slurry providing system provides
slurry to the surface of the polishing pad. The rotating carrier
holds the wafer and contacts the surface of the wafer with the
slurry and the polishing pad to carry out the chemical mechanical
polishing process.
Inventors: |
Chang, Hui-Chun; (Hsinchu,
TW) ; Lin, Tsang Jung; (Chungli City, TW) ;
Huang, Chao-Yuan; (Hsinchu, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
21766382 |
Appl. No.: |
10/014586 |
Filed: |
December 14, 2001 |
Current U.S.
Class: |
451/6 |
Current CPC
Class: |
B24B 37/205
20130101 |
Class at
Publication: |
451/6 |
International
Class: |
B24B 049/00 |
Claims
What is claimed is:
1. A chemical mechanical polishing apparatus for polishing a wafer,
comprising: a platen, comprising a light source for projecting a
light and a light detector for detecting the light reflected by the
wafer; a polishing pad having a first opening on the platen; a
transparent element detachably located on the first opening for
admitting light; a slurry providing system, which provides a slurry
to the surface of the polishing pad; and a rotating carrier for
holding the wafer and contacting the surface of the wafer with the
slurry and the polishing pad to carry out the chemical mechanical
polishing process.
2. The chemical mechanical polishing apparatus as claimed in claim
1, wherein the light is a laser beam.
3. The chemical mechanical polishing apparatus as claimed in claim
1, wherein the polishing pad comprises: a first substrate having a
second opening on the platen; and a second substrate installed on
the first substrate and having a third opening, wherein the second
opening and the third opening constitute the first opening.
4. The chemical mechanical polishing apparatus as claimed in claim
3, wherein the material type of the first substrate is suba IV.
5. The chemical mechanical polishing apparatus as claimed in claim
1, wherein the material type of the second substrate is
IC-1000.
6. The chemical mechanical polishing apparatus as claimed in claim
1, wherein the transparent element is installed on the second
opening.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates in general to a chemical
mechanical polishing apparatus (CMP apparatus). In particular, the
present invention relates to an in-situ type chemical mechanical
polishing apparatus for detecting the polishing endpoint.
[0003] 2. Description of the Related Art
[0004] At present, chemical mechanical polishing (CMP) is the only
way to realize a true global planarization in the manufacture of
integrated circuits. A semiconductor substrate is bathed or rinsed
in polishing slurry while an elastomeric pad is pressed against the
substrate and rotated so that the slurry particles are pressed
against the substrate under load. The lateral motion of the pad
causes the slurry particles to move across the substrate surface,
resulting in chemical and mechanical removal of the substrate
surface.
[0005] FIG. 1 shows a section view of the conventional CMP
apparatus. The type of the CMP apparatus is an in-situ detecting
end point type CMP apparatus.
[0006] A rotating carrier 110 comprising a transmission shaft 100
is used for holding and rotating a wafer 120. A platen 140 rotates
by a spindle 130. In addition, the platen 140 comprises a light
source 1401 for projecting a laser beam 1400 and a light detector
1402 for detecting the laser beam 1400 reflected by the wafer 120.
The polishing end point is detected by detecting the laser beam
1400 reflected by the wafer 120. The material of the platen 140 is
transparent, therefore the laser beam 1400 can be projected to the
outside of the platen 140.
[0007] FIG. 2 shows a section view of the conventional polishing
pad. The pad 150 is fixed on the platen 140 by glue 160. The pad
150 comprises an opening 1501 for installing a transparent window
1502, whereby the laser beam 1400 can pass the pad 150 through the
transparent window 1502.
[0008] In FIG. 1, slurry 180 is provided on the surface of the pad
150 by a slurry providing system 170. The wafer 120 is bathed or
rinsed in polishing slurry 180 while the polishing pad 150 is
pressed against the wafer 120 and rotated so that the slurry
particles 180 are pressed against the wafer 120.
[0009] In addition, the conventional in-situ type CMP apparatus's
detection of the polishing endpoint is by determining the optical
characteristics of the laser beam 1400 reflected by the wafer 120.
The structure and operation of the conventional in-situ type CMP
apparatus is described in U.S. Pat. No. 5,559,428.
[0010] However, when the polishing pad 150 is idle for a long time,
the transparent window 1502 is blurred due to water permeating,
resulting in a mistaken determination of the polishing endpoint.
Since the conventional CMP apparatus's transparent window 1502 is
fixed to the opening of the pad 150, to solve the problem, the pad
150 must be changed despite its remaining usability, which raises
the cost of process. Moreover, during changing of the pad 150, the
whole CMP system must be shut down and engineers must set up the
pad on the CMP apparatus accurately. Therefore, the efficiency of
the process is compromised.
SUMMARY OF THE INVENTION
[0011] The object of the present invention is to provide a CMP
apparatus having a transparent window detachably located on the
pad. When the transparent window is blurred due to water
permeating, only the blurred transparent window need be changed
without changing the whole polishing pad. Moreover, the location of
the transparent window according to the present invention is closer
to the platen than the conventional in-situ type CMP apparatus, so
the probability of water permeating decrease. Therefore, the
situation of transparent window being blurred is improved.
[0012] To achieve the above-mentioned object, the present invention
provides a chemical mechanical polishing apparatus for polishing a
wafer. The chemical mechanical polishing apparatus comprises a
platen, a polishing pad, a transparent element (transparent
window), a slurry providing system, and a rotating carrier. The
platen comprises a light source for projecting a light and a light
detector for detecting the light reflected by the wafer. The
polishing pad has a first opening on the platen. The transparent
element is detachably located on the first opening to admit light.
The slurry providing system provides slurry to the surface of the
polishing pad. The rotating carrier holds the wafer, and contacting
the surface of the wafer with the slurry and the polishing pad to
carry out the chemical mechanical polishing process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings, given byway of illustration only and thus not intended to
be limitative of the present invention.
[0014] FIG. 1 shows a section view of the conventional CMP
apparatus.
[0015] FIG. 2 shows a section view of the conventional polishing
pad.
[0016] FIG. 3 shows a section view of the CMP apparatus according
to the embodiment of the present invention.
[0017] FIG. 4 shows a section view of the polishing pad according
to the embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] FIG. 3 shows a section view of the CMP apparatus according
to the embodiment of the present invention. The type of the CMP
apparatus is an in-situ detecting end point type CMP apparatus.
[0019] A rotating carrier 210 comprising a transmission shaft 200
is used for holding and rotating a wafer 220. A platen 240 rotates
by a spindle 230. In addition, the platen 240 comprises a light
source 2401 for projecting a laser beam 2400 and a light detector
2402 for detecting the laser beam 2400 reflected by the wafer 220.
The polishing end point is detected by detecting the laser beam
2400 reflected by the wafer 220. The material of the platen 240 is
transparent, therefore the laser beam 2400 can be projected to the
outside of the platen 240.
[0020] FIG. 4 shows a section view of the polishing pad according
to the embodiment of the present invention. The pad 250 is fixed on
the platen 240 by glue 260. The pad 250 comprises a first substrate
2501 and a second substrate 2502. The first substrate 2501
comprises an opening and is located on the platen 240, the material
type of the first substrate 2501 is suba IV. The second substrate
2502 comprises another opening 2503 and is located on the first
substrate 2501, the material type of the second substrate 2502 is
IC-1000. In addition, the openings of the first substrate 2501 and
the second substrate 2502 overlap, and the transparent window 2504
is deposed on the opening of the first substrate 2501. The
transparent window 2504 in the present invention can be removed
from the first substrate 2501 by the user when blurred. The user
can then reinstall a new transparent window 2504 to the
substrate.
[0021] In FIG. 3, slurry 280 is provided on the surface of the pad
250 by a slurry providing system 270. The wafer 220 is bathed or
rinsed in polishing slurry 280 while the polishing pad 250 is
pressed against the wafer 220 and rotated so that the slurry
particles 280 are pressed against the wafer 220.
[0022] In addition, the in-situ type CMP apparatus's detection of
the polishing endpoint is by determining the optical
characteristics of the laser beam 2400 reflected by the wafer
220.
[0023] When the polishing pad 250 is idle for a long time, the
transparent window 2502 is blurred due to water permeating,
resulting in a mistaken determination of the polishing endpoint.
The user needs only remove the transparent window 2502 from the
first substrate 2501 and wipe down the wetness on the platen, then
paste a new transparent window 2502 onto the first substrate 2501,
rather than replacing the entire polishing pad. Moreover, the
location of the transparent window according to the present
invention is closer to the platen than the conventional in-situ
type CMP apparatus, so the probability of water permeating
decreases.
[0024] Accordingly, the invention not only simplifies the pad
changing procedure and decreases maintenance time, but also
decreases the cost of the process and human resources. Furthermore,
the present invention solves the problems of polishing endpoint
misdetermination due to water permeating and improves the
effectiveness of the polishing operation.
[0025] The foregoing description of the preferred embodiments of
this invention has been presented for purposes of illustration and
description. Obvious modifications or variations are possible in
light of the above teaching. The embodiments were chosen and
described to provide the best illustration of the principles of
this invention and its practical application to thereby enable
those skilled in the art to utilize the invention in various
embodiments and with various modifications as are suited to the
particular use contemplated. All such modifications and variations
are within the scope of the present invention as determined by the
appended claims when interpreted in accordance with the breadth to
which they are fairly, legally, and equitably entitled.
* * * * *