U.S. patent application number 09/829221 was filed with the patent office on 2003-10-09 for chemical-mechanical polishing platform.
Invention is credited to Chou, Sam, Lien, Hao-Ming, Wang, Jiun-Fang, Yang, Ming-Cheng.
Application Number | 20030190873 09/829221 |
Document ID | / |
Family ID | 30118705 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030190873 |
Kind Code |
A1 |
Wang, Jiun-Fang ; et
al. |
October 9, 2003 |
Chemical-mechanical polishing platform
Abstract
A chemical-mechanical polishing platform that comprises a
polishing table, a wafer carrier, a polishing pad, a slurry
supplier, a conditioner, and a means for cleaning the polishing
pad. With respect to in-situ or ex-situ chemical-mechanical
polishing, the wafer carrier, conditioner, and means for cleaning
the polishing pad are adequately disposed above the polishing pad.
The chemical-mechanical polishing is performed by rotation of the
polishing pad; the region of the polishing pad that has polished
the wafer then passes sequentially through the conditioner, the
means for cleaning that removes diamond particles that may drop on
the polishing pad, and through the slurry supplier that provides
adequate slurry such that the polishing process can be repeated
without scraping damage of the wafer. The means for cleaning of the
present invention can have any shapes adapted to remove diamond
particles on the polishing pad, such as circular or cylindrical
brush sweeper.
Inventors: |
Wang, Jiun-Fang; (Hsinchu
City, TW) ; Yang, Ming-Cheng; (Taipei, TW) ;
Lien, Hao-Ming; (Hsinchu, TW) ; Chou, Sam;
(Hsinchu Hsien, TW) |
Correspondence
Address: |
J.C. Patents, Inc.
4 Venture
Suite 250
Irvine
CA
92618
US
|
Family ID: |
30118705 |
Appl. No.: |
09/829221 |
Filed: |
April 9, 2001 |
Current U.S.
Class: |
451/56 |
Current CPC
Class: |
B24B 53/017 20130101;
B24B 53/02 20130101; H01L 21/6835 20130101 |
Class at
Publication: |
451/56 |
International
Class: |
B24B 053/00 |
Claims
What is claimed is:
1. A chemical-mechanical polishing platform that is suitable to be
used for in-situ chemical-mechanical polishing of a wafer, the
chemical-mechanical polishing platform comprising: a polishing
table that has a polishing pad located thereon, wherein the
polishing table rotates in a first direction to polish the wafer; a
wafer carrier that is directed to maintain the wafer to be polished
against the polishing pad; a conditioner having a plurality of
diamond particles, wherein the diamond particles are in contact
with the polishing pad, such that an adequate roughness of the
polishing pad is maintained when the polishing table rotates; and a
means for cleaning mounted above the polishing pad, wherein the
means for cleaning rotates such that diamond particle residues
dropping on the polishing pad can be removed.
2. The chemical-mechanical polishing platform of claim 1, further
comprising a slurry supplier arranged above the polishing pad and
between the wafer carrier and means for cleaning.
3. The chemical-mechanical polishing platform of claim 2, wherein
the slurry supplier further comprises: a supply tube that supplies
the polishing pad with slurry; and a pump that conducts the slurry
to the supply tube.
4. The chemical-mechanical polishing platform of claim 1, wherein
the means for cleaning is round-shaped, and performs a rotation
movement according to a direction identical to the rotation of the
polishing table.
5. The chemical-mechanical polishing platform of claim 1, wherein
the means for cleaning is cylindrical-shaped and performs a
rotation movement.
6. A chemical-mechanical polishing platform that is suitable to be
used for ex-situ chemical-mechanical polishing of a wafer, the
chemical-mechanical polishing platform comprising: a polishing
table that has a polishing pad located thereon, wherein the
polishing table rotates in a first direction to polish the wafer; a
wafer carrier that is directed to maintain the wafer to be polished
against the polishing pad; a conditioner having a plurality of
diamond particles, wherein the diamond particles are in contact
with the polishing pad, such that an adequate roughness of the
polishing pad is maintained when the polishing table rotates; and a
means for cleaning mounted above the polishing pad, wherein the
means for cleaning rotates such that diamond particle residue
dropping on the polishing pad can be removed.
7. The chemical-mechanical polishing platform of claim 6, further
comprising a slurry supplier arranged along the first direction of
rotation of the polishing pad between the means for cleaning and
wafer carrier.
8. The chemical-mechanical polishing platform of claim 6, wherein
the slurry supplier further comprises: a supply tube that supplies
the polishing pad with slurry; and a pump that conducts the slurry
to the supply tube.
9. The chemical-mechanical polishing platform of claim 6, wherein
the means for cleaning is round-shaped, and performs a rotation
movement according to a direction identical to the rotation of the
polishing table.
10. The chemical-mechanical polishing platform of claim 6, wherein
the means for cleaning is cylindrical-shaped and performs a
rotation movement.
11. A method for performing a chemical-mechanical polishing on a
wafer using a polishing pad that can prevent damages of the wafer
by diamond particles dropped on the polishing pad, the method
comprising: providing the polishing pad with a slurry; rotating the
polishing pad to polish the wafer; scraping the polishing pad to
maintain an adequate roughness thereof; and cleaning away diamond
particles that may drop on the polishing pad.
12. The method of claim 11, wherein in an in-situ
chemical-mechanical polishing, the step of cleaning away diamond
particles is performed simultaneously with the polishing of the
wafer by rotating the polishing pad.
13. The method of claim 11, wherein in an ex-situ
chemical-mechanical polishing, the step of cleaning away diamond
particles is alternately performed with the polishing of the
wafer.
14. The method of claim 11, wherein the cleaning of the polishing
pad is performed via a substantially rounded brush sweeper.
15. The method of claim 11, wherein the cleaning of the polishing
pad is performed via a substantially cylindrical brush sweeper.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to chemical-mechanical polishing. More
particularly, the present invention relates to a
chemical-mechanical polishing platform.
[0003] 2. Description of the Related Art
[0004] In semiconductor processes, the quality of the surface of
the substrate is critical to prepare the substrate for a subsequent
photolithography process. High accuracy of the pattern transfer
onto the substrate during the photolithography process is ensured
only if the surface of the substrate does not present irregularity
that can scatter the light during exposure. Presently,
planarization techniques principally comprise spin-on glass (SOG)
and chemical-mechanical polishing. However, since the semiconductor
processes has been in the era of a sub-half-micron technology,
spin-on glass (SOG) can no longer satisfy the requirement of
accuracy for the planarization. Hence, the chemical-mechanical
polishing technique is chosen because it provides a global
planarization and satisfies the criteria for very large scale
integration (VLSI), and even for ultra large scale integration
(ULSI). Chemical-mechanical polishing produces a chemical reaction
by using a slurry which comprises specific reagents introduced to
the surface of a wafer to form an abrasive layer, and then the
un-planarized parts on the abrasive layer are mechanically polished
by the abrasive particles in the slurry. Thus, the wafer can be
planarized by repeat chemical-mechanical polishing.
[0005] Referring to FIG. 1A and FIG. 1B, a top view and a
cross-sectional view respectively show a conventional in-situ
chemical-mechanical polishing platform. The chemical-mechanical
polishing platform 100 can be used according to an in-situ or
ex-situ fashion. The in-situ chemical-mechanical polishing platform
comprises a polishing table 101, a wafer carrier 102, a polishing
pad 104, a slurry supplier tube 106, a pump 108, and a conditioner
110. The wafer carrier 102 maintains the surface of the wafer to be
planarized against the polishing pad 104. The slurry supplier tube
106 and pump 108 supply the polishing pad 104 with necessary slurry
comprising adequate reagents to perform the polishing, while the
conditioner 110, provided with diamond particles in contact with
the polishing pad 104, maintains an adequate roughness of the
polishing pad 104 and cleans away undesirable particles. Thus, a
sufficient adsorption of the slurry and a stable polishing rate are
maintained.
[0006] The principal difference between in-situ and ex-situ
chemical-mechanical polishing is that in in-situ
chemical-mechanical polishing, the polishing of the wafer,
maintenance of the roughness of the polishing pad, and cleaning
away of undesirable particles are simultaneously performed on the
polishing pad, while, in ex-situ chemical-mechanical polishing, the
conditioner is applied onto the polishing pad only after the
polishing of the wafer has been completed.
[0007] An important problem of the above conventional
chemical-mechanical polishing platform is that diamond particles of
the conditioner may drop on the polishing pad, which scratches and
irreversibly damages the wafer. This problem is caused by the
corrosive characteristic of the slurry and mechanical forces that
are regularly exerted on the diamond particles of the conditioner
during polishing.
[0008] A chemical-mechanical polishing that does not damage the
wafer to be polished would reduce the amount of damaged wafers and
improve the general manufacturing yield.
SUMMARY OF THE INVENTION
[0009] One major aspect of the present invention is to provide a
chemical-mechanical polishing platform comprising a means for
cleaning away particle residue dropped on the polishing pad.
[0010] To attain the foregoing and other objects, a
chemical-mechanical polishing platform, according to an embodiment
of the present invention, comprises: a polishing table, a wafer
carrier, a polishing pad fixed onto the polishing table, a slurry
supplier, a conditioner, and a cleaning device. With respect to an
in-situ chemical-mechanical polishing, the wafer carrier,
conditioner, cleaning device, and slurry supplier are adequately
disposed above the polishing table such that when the polishing
table rotates to perform polishing, the polishing pad passes
sequentially under the conditioner, the cleaning device, and the
slurry supplier after passing under the wafer carrier. The
conditioner continuously maintains an adequate roughness of the
polishing pad during polishing of the wafer. The cleaning device
cleans away residue dropped on the polishing pad, such as diamond
particles dropped from the conditioner, thereby preventing the
wafer from being damaged. After the cleaning device cleans away
residue, the slurry supplier supplies the polishing pad with
sufficient slurry to maintain a stable polishing rate. With respect
to ex-situ chemical-mechanical polishing, the arrangement of the
wafer carrier, conditioner, cleaning device, and slurry supplier
are not as restrictive as in in-situ chemical-mechanical polishing.
In the embodiments and examples of the present invention, the
cleaning device can be for example a brush sweeper of any shape
adapted for cleaning away residue dropped on the polishing pad.
[0011] It is to be understood that both the foregoing general
description and the following detailed description are exemplary,
and are intended to provide further explanation of the invention as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention. In the
drawings,
[0013] FIG. 1A and FIG. 1B are respectively a top view and a
side-view schematically illustrating a conventional in-situ
chemical-mechanical polishing platform;
[0014] FIG. 2 is a top view schematically illustrating an in-situ
chemical-mechanical polishing platform, according to an embodiment
of the present invention;
[0015] FIG. 3A and FIG. 3B are top views schematically illustrating
an ex-situ chemical-mechanical polishing platform according to an
embodiment of the present invention; and
[0016] FIG. 4 is a top view schematically illustrating another
example of a chemical-mechanical polishing platform according to an
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] The following detailed description of the embodiments and
examples of the present invention with reference to the
accompanying drawings is only illustrative and not limiting.
Wherever possible, like reference numerals are used to refer to
like elements.
[0018] Referring now to FIG. 2, a top view schematically
illustrates an in-situ chemical-mechanical polishing platform,
according to an embodiment of the present invention. The in-situ
chemical-mechanical polishing platform principally comprises: a
polishing table 201, a wafer carrier 202, a polishing pad 204, a
slurry supplier, a conditioner 210, and a cleaning device 216. For
example of illustration, the cleaning device 216 can be for example
a brush sweeper. The wafer carrier 202 maintains a wafer 212 to be
polished in contact with the polishing pad 204. The polishing pad
204 is, for example, a polyimide IC 1000 material arranged on the
polishing table 201. The conditioner 210, typically a diamond
dresser, is in contact with the polishing pad 204. The conditioner
210 is provided, by its contact surface with the polishing pad 204,
with a plurality of diamond particles, such that when the polishing
table 201 rotates to perform the polishing, the diamond particles
scrape the polishing pad 204. As a result, a substantial roughness
of the polishing pad 204 can be maintained. The slurry supplier,
that comprises typically a pump 208 and an outlet tube 206,
provides the polishing pad 204 with necessary slurry 214. The
cleaning device 216 cleans out the diamond particles that may drop
from the conditioner 210 onto the polishing pad 204, thereby
preventing the wafer 212 from being scratched during the in-situ
polishing process.
[0019] When a chemical-mechanical polishing is performed on a wafer
212, the wafer carrier 202 presses on a back surface of the wafer
212, thereby maintaining a front surface of the wafer 212 to be
polished against the polishing pad 204. The wafer carrier 202,
conditioner 210, and cleaning device 216 are disposed sequentially
on the polishing pad 204. Hence, when the polishing table 201
rotates, for instance according to a first direction 218, the
region of the polishing pad 204 that has passed under the wafer 212
is scraped by the conditioner 210. Thus, an adequate roughness of
the polishing pad 204 can be continuously maintained during
polishing, resulting in the maintenance of a stable polishing rate
of the wafer. The cleaning device 216 can be, for example, a
rounded-shape device capable to rotate according to a second
direction 220, such that it cleans away undesirable residue that
may drop on the polishing pad 204, such as diamond particles from
the conditioner 210. Thus, the wafer 212 can be prevented from
being scratched during polishing. The slurry 214 is regularly
supplied to the polishing pad 204 by the slurry supplier at the
region I between the wafer carrier 202 and the cleaning device 216.
With the regular maintenance of the roughness of the surface of the
polishing pad 204 combined with the cleaning action of the cleaning
device, the slurry 214 can thus adequately adsorb on the polishing
pad 204, and a stable polishing rate can be favorably
maintained.
[0020] Referring to FIG. 3A and FIG. 3B, top views schematically
illustrate an ex-situ chemical-mechanical polishing platform,
according to another embodiment of the present invention. Similar
to the above, the ex-situ chemical-mechanical polishing platform
principally comprises: the polishing table 201, the wafer carrier
202, the polishing pad 204, the slurry supplier, the conditioner
210, and the cleaning device 216. However, since the conditioning
of the polishing pad 204 is performed only after the wafer
polishing is completed and removed, the disposition of the
conditioner 210, cleaning device 216, and slurry supplier is thus
not restrictive, and any arrangements thereof are possible on the
polishing pad 204. The wafer carrier 202 presses on the wafer to
maintain its front surface to be polished against the polishing pad
204. After the wafer 212 is polished and removed from the polishing
pad 204, the conditioner 210 maintains an adequate roughness of the
polishing pad 204, while the cleaning device 216 cleans away
undesirable residue on the polishing pad 204, such as diamond
particles that might have dropped from the conditioner 210. As a
result, the slurry 214 provided by the slurry supplier adequately
adsorbs on the polishing pad 204, and a stable and efficient
polishing rate can be maintained for the following wafer to be
polished.
[0021] Referring to FIG. 4, a top view schematically illustrates
another example of the chemical-mechanical polishing platform,
according to an embodiment of the present invention. As shown in
FIG. 4, the cleaning device 216 can be, for example, a cylindrical
brush that rotates according to the third direction 222 to remove
undesirable residue out of the polishing pad 204.
[0022] The foregoing description of embodiments and examples of the
present invention reveals at least that the chemical-mechanical
polishing platform of the present invention, comprising the
cleaning device, can prevent the wafer that is polished from being
damaged by undesirable residue/abrasive particles dropped on the
polishing pad, such as diamond particles from the conditioner. Such
an advantage is obtained by simple modification of the conventional
chemical-mechanical polishing platform, that substantially reduces
the rate of defect wafers which are caused by dropped diamond
particles.
[0023] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention.
* * * * *