U.S. patent application number 10/112447 was filed with the patent office on 2003-10-02 for reinforced chemical mechanical planarization belt.
This patent application is currently assigned to Lam Research Corporation. Invention is credited to Hymes, Diane J., Lin, Jibing.
Application Number | 20030186630 10/112447 |
Document ID | / |
Family ID | 28453331 |
Filed Date | 2003-10-02 |
United States Patent
Application |
20030186630 |
Kind Code |
A1 |
Lin, Jibing ; et
al. |
October 2, 2003 |
Reinforced chemical mechanical planarization belt
Abstract
A processing belt for use in chemical mechanical planarization
(CMP), and methods for making the same, are provided. Embodiments
of the processing belt include a polymeric material reinforced with
a woven fabric or synthetic material encased between the polymeric
material and an additional polymeric material layer to define the
processing belt. The processing belt is fabricated so that the
woven fabric forms a continuous loop and is positioned against a
surface of the polymeric material. The additional polymeric
material layer is applied over the woven fabric, permeating the
woven fabric to bond to the polymeric material forming an integral
structure of woven fabric reinforced polymeric material.
Inventors: |
Lin, Jibing; (Fremont,
CA) ; Hymes, Diane J.; (San Jose, CA) |
Correspondence
Address: |
MARTINE & PENILLA, LLP
710 LAKEWAY DRIVE
SUITE 170
SUNNYVALE
CA
94085
US
|
Assignee: |
Lam Research Corporation
Fremont
CA
|
Family ID: |
28453331 |
Appl. No.: |
10/112447 |
Filed: |
March 29, 2002 |
Current U.S.
Class: |
451/81 |
Current CPC
Class: |
B24D 11/005 20130101;
B24B 37/24 20130101; B24B 37/26 20130101; B24B 21/04 20130101 |
Class at
Publication: |
451/81 |
International
Class: |
B24C 003/08; B24C
003/18 |
Claims
What is claimed is:
1. A processing belt for use in chemical mechanical planarization
(CMP), comprising: a fabric belt; and a polymeric material encasing
the fabric belt to define the processing belt to be used in CMP
operations.
2. The processing belt of claim 1, wherein the fabric belt forms a
continuous loop within the polymeric material.
3. The processing belt of claim 1, wherein the fabric belt is
defined of kevlar.
4. The processing belt of claim 3, further comprising openings in
the fabric belt, the openings being configured to be suitable for
optical transmissions through the opening in the fabric.
5. The processing belt of claim 4, wherein the polymeric material
is made thinner at the opening in the fabric.
6. The processing belt of claim 1, wherein the fabric belt is
defined of a synthetic material including polyester, polyimide,
nylon, rayon, and PVC.
7. A belt for use in chemical mechanical planarization (CMP)
processing, comprising: a polymeric material being cast into a
continuous loop to define the belt; and a reinforcing fabric
embedded between the polymeric material and an additional polymeric
material layer, the reinforcing fabric being defined as a
continuous loop within the polymeric material and the additional
polymeric material layer.
8. The belt of claim 7, wherein the polymeric material includes
polyurethane, polyester, PVC, polyacrylate, and epoxy.
9. The belt of claim 7, wherein the additional polymeric material
layer is defined by one of polyurethane, polyester, PVC,
polyacrylate, and epoxy.
10. The belt of claim 7, wherein the reinforcing fabric is defined
as a woven and porous structure.
11. The belt of claim 7, further comprising openings fabricated in
the reinforcing fabric, the openings being suitable for optical
transmissions through the reinforcing fabric.
12. The belt of claim 11, wherein the polymeric material and the
additional polymeric material layer are made thinner at the
openings in the reinforcing fabric.
13. The belt of claim 7, wherein the reinforcing fabric is defined
from kevlar.
14. The belt of claim 7, wherein the reinforcing fabric is defined
of a synthetic fiber including nylon, polyester, polyimide, rayon,
and PVC.
15. The belt of claim 7, further comprising: a processing surface
defined over the polymeric material, the polymeric material being a
first polymeric material and the processing surface being defined
from a second polymeric material bonded to the first polymeric
material.
16. A processing belt for use in chemical mechanical planarization
(CMP), comprising: a continuous loop reinforcing woven fabric; a
continuous loop polymeric material; and a continuous loop
additional polymeric material layer bonded to the continuous loop
polymeric material and encasing the continuous loop reinforcing
woven fabric between the continuous loop polymeric material and the
continuous loop additional polymeric material layer to define the
processing belt to be used in CMP operations, wherein the
continuous loop reinforcing woven fabric is defined from one of
kevlar, nylon, polyimide, and polyester.
17. The processing belt of claim 16, wherein the continuous loop
reinforcing woven fabric includes openings that allow optical
transmission to pass through the continuous loop reinforcing
fabric.
18. The processing belt of claim 17, wherein the continuous loop
polymeric material and the continuous loop additional polymeric
material encasing the continuous loop reinforcing woven fabric are
thinner at the openings than the continuous loop polymeric material
and the continuous loop additional polymeric material encasing the
continuous loop reinforcing woven fabric in regions other than at
the openings.
19. A method for fabricating a belt for use in chemical mechanical
planarization (CMP), comprising: forming a belt-shaped fabric;
providing a mold configured to form a belt-shaped structure;
forming a polymeric material in the mold; attaching the belt shaped
fabric to the formed polymeric material; and applying an additional
polymeric material layer over the belt-shaped fabric, the applying
being over and through the belt-shaped fabric such that the
belt-shaped fabric is encased between the polymeric material and
the additional polymeric material layer, the polymeric material and
the additional polymeric material layer being bonded together.
20. The method of claim 19, further comprising: defining a
polymeric processing surface over the polymeric material.
21. The method of claim 19, wherein the forming a belt-shaped
fabric includes forming openings through the belt-shaped fabric
through which optical transmissions can pass.
22. The method of claim 19, wherein the belt-shaped fabric is
formed of kevlar.
23. The method of claim 19, wherein the polymeric material includes
polyurethane, polyester, PVC, polyacrylate, and epoxy.
24. The method of claim 19, wherein the additional polymeric
material layer is defined of one of polyurethane, polyester, PVC,
polyacrylate, and epoxy.
25. The method of claim 19, wherein the polymeric material and the
additional polymeric material layer encasing the belt-shaped fabric
are chemically bonded together.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to wafer preparation
belts, and more specifically to the fabrication of belt materials
used in chemical mechanical planarization apparatus.
[0003] 2. Description of the Related Art
[0004] In the fabrication of semiconductor devices, a plurality of
layers are typically disposed over a substrate, and features are
defined in and through the layers. A surface topography of the
substrate or wafer can become irregular during fabrication
processes, and an un-corrected irregularity increases with the
addition of subsequent layers. Chemical Mechanical Planarization
(CMP) has developed as a fabrication process utilized to planarize
the surface of a semiconductor wafer, as well as to perform
additional fabrication processes including polishing, buffing,
substrate cleaning, etching processes, and the like.
[0005] In general, CMP processes involve the application of a
substrate or wafer against a processing surface with a controlled
pressure. Both the processing surface and the wafer are caused to
rotate, spin, or otherwise move independently of one another to
create a frictional force for planarization and to ensure the
entire surface of the wafer is consistently and controllably
processed. Typical CMP apparatus include linear belt processing
systems in which a belt having a processing surface is supported
between two or more drums or rollers which move the belt through a
rotary path presenting a flat processing surface against which the
wafer is applied. The wafer is typically supported and rotated by a
wafer carrier, and a polishing platen is configured on the
underside of the belt traveling in its circular path. The platen
provides a stable surface over which the belt travels, and the
wafer is applied to the processing surface of the belt against the
stable surface provided by the platen. In some applications,
abrasives in an aqueous solution known as slurry is introduced to
facilitate and enhance the planarization or other CMP process.
[0006] Additional CMP apparatus include rotary CMP processing tools
having a circular pad configuration for the processing surface, an
orbital CMP processing tool similar to the circular CMP processing
tool, a sub-aperture CMP processing tool, and other CMP processing
systems providing a plurality of apparatus and configurations that,
in general, utilize friction to planarize, scrub, polish, buff,
clean, or otherwise process the surface of a semiconductor wafer
having integrated circuits or other structures fabricated
thereon.
[0007] In the linear belt CMP system, the belt and processing
surface are typically fabricated to provide a stable structure to
withstand the stresses of the belt and drum configuration, as well
as a stable processing surface upon which precise and controllable
planarization can occur. In addition to the stretching and
contraction caused by the belt and processing surface traveling
around the drums that drive the system, the belt and processing
surface are typically in a wet environment from the liquid from
slurry and rinsing operations. Belts and processing surfaces are
typically constructed of a plurality of materials such as, by way
of example, a stainless steel supporting layer, a cushioning layer,
and one or more processing surface layers. The plurality of layers
are joined by adhesives, bonding, stitching, and the like to form
the continuous belt structure with an outwardly facing processing
surface against which a wafer is applied in a CMP process.
[0008] The fabrication of linear belts in a plurality of layers as
described provides the necessary support to substantially prevent
the stretching of linear CMP belts, but such belts can be difficult
to work with, and manufacturing costs associated with belt
construction are increased. Some CMP processing belts include
substantially polymer material without the additional layers
described above. The substantially polymer material belts, however,
tend to stretch and otherwise deform with continued use. Attempts
to reinforce substantially polymer CMP processing belts have been
largely unsuccessful, with functional belts substantially resulting
in multi-layer processing belts as described above.
[0009] Linear belts used in linear belt CMP systems can be costly
to manufacture, and can be time consuming to replace. Replacement
of linear belts requires down time for the CMP system resulting in
decreased through put and increased manufacturing costs.
Multiple-layer linear belts can be subject to such failures as
delamination or separation of the layers due to such factors as the
contraction and stretching forces during use, and the breakdown of
adhesives or other bonding techniques over time and accelerated in
the wet CMP environment.
[0010] In view of the foregoing, what is needed are methods,
processes, and apparatus to fabricate a linear CMP processing belt
that is resilient to the stresses of use, is less likely to
delaminate or otherwise separate, is economical and easy to
manufacture, and is easy to work with in a plurality of CMP
processing tools and environments.
SUMMARY OF THE INVENTION
[0011] Broadly speaking, the present invention fills these needs by
providing a reinforced polymeric CMP processing belt. The present
invention can be implemented in numerous ways, including as a
process, an apparatus, a system, a device, or a method. Several
embodiments of the present invention are described below.
[0012] In one embodiment, a processing belt for use in chemical
mechanical planarization is disclosed. The processing belt includes
a fabric belt and a polymeric material encasing the fabric belt to
define the processing belt to be used in chemical mechanical
planarization operations.
[0013] In another embodiment, a belt for use in chemical mechanical
planarization processing is disclosed. The belt includes a
polymeric material cast into a continuous loop to define the belt,
and a reinforcing fabric embedded between the polymeric material
and an additional polymeric material layer. The reinforcing fabric
is defined as a continuous loop within the polymeric material and
the additional polymeric material layer.
[0014] In yet another embodiment, a processing belt for use in
chemical mechanical planarization is disclosed. The processing belt
includes a continuous loop reinforcing woven fabric, a continuous
loop polymeric material, and a continuous loop additional polymeric
material layer. The continuous loop additional polymeric material
layer is bonded to the continuous loop polymeric material encasing
the continuous loop reinforcing woven fabric between the bonded
materials to define the processing belt to be used in chemical
mechanical planarization operations. The continuous loop
reinforcing woven fabric is defined from one of kevlar, nylon,
polyimide, and polyester.
[0015] In still a further embodiment, a method for fabricating a
belt for use in chemical mechanical planarization is disclosed. The
method includes forming a belt-shaped fabric, and providing a mold
configured to form a belt-shaped structure. A polymeric material is
formed in the mold, and the belt shaped fabric is attached to the
formed polymeric material. The method further includes applying an
additional polymeric material layer over the belt-shaped fabric.
The additional polymeric material layer is applied over and through
the belt-shaped fabric such that the belt-shaped fabric is encased
between the polymeric material and the additional polymeric
material layer. The polymeric material and the additional polymeric
material layer are bonded together. Such bond can form a chemical
bond, and can be adhered together as an essentially integral
structure.
[0016] The advantages of the present invention are numerous. One
notable benefit and advantage of the invention is significantly
increased lifetime of the polymeric CMP processing belt in the CMP
process. Unlike a typical linear CMP processing belt of prior art,
the present invention provides the necessary strength, support, and
resilience without stacks of bonded layers subject to delamination
or separation. The reinforcement of the present invention can be
chemically bonded, and is at least adhered to the processing belt
in a manner so as to be integral to the belt structure. Polymeric
material provides the supporting structure which is reinforced and
may include a separately fabricated processing surface, resulting
in a CMP processing belt of significantly increased lifetime in the
CMP process.
[0017] Another benefit is the lower cost and ease of manufacture.
Unlike typical prior art processing belts, the present invention
includes a supporting and predominate structure of polymeric
material. The plurality of layers, adhesives, stitches, or other
bonding materials between the plurality of layers are eliminated
without compromise of strength, support, and resilience.
Reinforcing material is easily obtained, easy to work with, and
easily applied to a surface of the polymeric processing belt.
[0018] An additional benefit is the ability to readily integrate
embodiments of the present invention with optical end point
detection apparatus. The reinforcing layer of the present invention
provides for fabrication of optical "windows" for use with end
point detection apparatus, and without compromise of necessary
strength, support, and resilience. Further, integration of optical
end point detection structures does not increase the likelihood of
delamination or separation, or decrease the useable life of the
processing belt.
[0019] Other advantages of the invention will become apparent from
the following detailed description, taken in conjunction with the
accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The present invention will be readily understood by the
following detailed description in conjunction with the accompanying
drawings, wherein like reference numerals designate like structural
elements.
[0021] FIG. 1A illustrates a typical linear belt CMP system.
[0022] FIG. 1B shows a side view of the linear belt CMP system
described in FIG. 1A.
[0023] FIG. 2A shows a cross section of a typical linear CMP
processing belt.
[0024] FIG. 2B shows the cross section of a typical linear CMP
processing belt of FIG. 2A with an open section of belt for use
with an in-situ optical end point detection system.
[0025] FIG. 3A is a cross section of a CMP processing belt in
accordance with an embodiment of the present invention.
[0026] FIG. 3B is a cross section of a CMP processing belt in
accordance with an embodiment of the present invention.
[0027] FIG. 4 shows a detail view of the application of the
additional polymeric material layer described in reference to FIGS.
3A and 3B in accordance with one embodiment of the invention.
[0028] FIG. 5 shows a cross section of a CMP processing belt in
accordance with another embodiment of the present invention.
[0029] FIG. 6 is a flow chart diagram illustrating the method
operations for manufacturing a reinforced polymeric CMP processing
belt in accordance with one embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] An invention for a CMP processing belt and methods for
making the same are disclosed. In preferred embodiments, the CMP
processing belt includes a processing belt constructed of a
polymeric material and reinforced with a woven fabric or synthetic
material to define the processing belt to be used in CMP
operations.
[0031] In the following description, numerous specific details are
set forth in order to provide a thorough understanding of the
present invention. It will be understood, however, to one skilled
in the art, that the present invention may be practiced without
some or all of these specific details. In other instances, well
known process operations have not been described in detail in order
not to unnecessarily obscure the present invention.
[0032] FIG. 1A illustrates a typical linear belt CMP system 100. A
linear CMP processing belt 102 is positioned around two drums 104.
A wafer 106 for processing is attached to a wafer carrier 108 over
the linear belt CMP system 100. The wafer carrier 108 is caused to
rotate 110 which causes the wafer 106 to rotate, and the drums 104,
also known as drive rollers 104, rotate causing the linear CMP
processing belt 102 to move in direction 112. The rotating wafer
carrier 108 having a wafer 106 attached thereto is applied against
the linear CMP processing belt 102 which is moving around drums 104
in direction 112. Platen 114 is positioned under linear CMP
processing belt 102 opposite (e.g., on the opposite side of the
linear CMP processing belt 102 from) the wafer carrier 108 with a
wafer 106 attached. Platen 114 provides additional support in order
for the wafer 106 to be applied against the linear CMP processing
belt 102 with sufficient force to accomplish the desired
planarization or other CMP process, as well as providing a flat
surface for consistent, measurable processing. FIG. 1B shows a side
view of the linear belt CMP system 100 just described.
[0033] As can be appreciated from FIGS. 1A and 1B, the linear CMP
processing belt 102 is subjected to various stresses during
operation of the linear belt CMP system 100. By way of example, as
a point on the linear CMP processing belt 102 travels around drums
104, it is subjected to a stretching force, with the outer region
or exterior surface of the linear CMP processing belt 102 subjected
to greater stretching than the inner region or interior surface of
the linear CMP processing belt. As the point on the linear CMP
processing belt continues travel off of and away from the drums
104, it is subjected to a contracting force as the belt straightens
out and travels across the top or bottom of the linear belt CMP
system 100 towards the next drum 104. Further, the linear belt CMP
processing system 100 subjects the linear CMP processing belt 102
to processing stresses such as the downward force of the wafer
against the processing surface, the frictional contact between the
rotating wafer 106 and the linear CMP processing belt 102, and
other such processing forces.
[0034] FIG. 2A shows a cross section of a typical linear CMP
processing belt 120. The exemplary linear CMP processing belt 120
includes three layers 122, 124, and 126. The top polymeric layer
122 provides the processing surface against which the wafer 106
(see FIGS. 1A, 1B) is applied for CMP processing. A cushioning
layer 124 is typically constructed between the processing surface
polymeric layer 122 and the support or base layer 126, and provides
a cushioning transition layer between the processing surface
polymeric layer 124, and the rigid, hard support or base layer 126.
Typically, the support or base layer 126 is a solid stainless steel
or other similar metal belt or band over which has been fabricated
the cushioning layer 124 and polymeric processing surface layer
122. The plurality of layers are typically joined by adhesives or
other similar bonding of one layer to the next.
[0035] FIG. 2B shows the cross section of a typical linear CMP
processing belt 120 of FIG. 2A with an open section 128 of belt for
use with an in-situ optical end point detection (EPD) system. As
can be appreciated in FIG. 2B, a section of the linear CMP
processing belt 120 is removed, including the support or base layer
126, the cushioning layer 124, and the processing surface polymeric
layer 122. When an open section 128 is constructed in a linear CMP
processing belt 120, an open section 128 of sufficient size for
optical EPD implementation is created in the linear processing belt
120. Typically, sufficient size includes a small circular, oval or
square section of the linear CMP processing belt 120 that varies in
size according to the particular processing tool with a typical
dimension of about 1.25 inches in length and about 0.75 inches in
width, and therefore not an entire width of the linear CMP
processing belt 120, or of such a large size as to significantly
weaken the structural integrity of the linear CMP processing belt
120. Construction of the open section 128 for EPD use typically
includes forming a hole or opening in the linear CMP processing
belt 120 and through each of the processing surface polymeric layer
122, the cushioning layer 124, and the support or base layer
126.
[0036] As described above, the stretching and contracting forces
caused during normal use of the linear CMP processing system 100
(see FIGS. 1A and 1B) can cause delamination or separation in a
linear CMP processing belt 120 such as exemplary belt illustrated
in FIG. 2A. The effects of the stresses of normal wear are
aggravated by the wet environment including the use of slurries,
rinses, and the like. Structures such as the open section 128
illustrated in FIG. 2B can increase the likelihood for linear CMP
processing belt 120 to suffer structural failure including
delamination or separation due to the increased surface area
subjected to stress, increased likelihood of exposure of the layer
joints and adhesives or other bonds to the wet environment,
structural weakening of the base or support layer 126 from the
opening or openings created, and the like.
[0037] FIG. 3A is a cross section of a CMP processing belt 150 in
accordance with an embodiment of the present invention. In the
inventive CMP processing belt 150 shown in FIG. 3A, the CMP
processing belt 150 is constructed substantially of a polymeric
material 152 with a woven fabric or synthetic material reinforcing
layer 154, and an additional polymeric material layer 156 sprayed
on, or otherwise applied, bonding the woven fabric or synthetic
material reinforcing layer 154 to the polymeric material 152. The
polymeric material 152 can include any of a plurality of polymeric
materials suitable for construction of CMP processing belts and
surfaces, including polyurethane, polyester, PVC, polyacrylate, any
of a plurality of epoxies, and the like.
[0038] In one embodiment, the woven fabric or synthetic material
reinforcing layer 154 is a fabric of kevlar. In other embodiments,
the fabric is constructed of synthetic materials such as synthetic
fibers of nylon, polyimides, polyesters, and the like, and in some
embodiments, the fabric is a combination of synthetic materials
such as, by way of example, nylon material forming one direction of
a weave, and polyester material forming another direction of the
weave. In this manner, the most desirable properties of the
particular synthetic such as strength, or rigidity, or elasticity,
are selectively implemented along and across a CMP processing belt
150 according to particular processing needs.
[0039] In the embodiment illustrated in FIG. 3A, additional
polymeric material layer 156 is shown bonding the woven fabric or
synthetic material reinforcing layer 154 to the polymeric material
152. The additional polymeric material layer 156 can include any of
the plurality of polymers suitable for use in the construction of a
CMP processing belt including polyurethane, polyester, PVC,
polyacrylate, any of a plurality of epoxies, and the like.
[0040] As illustrated in FIG. 3A, one embodiment of the present
invention includes the application of the additional polymeric
material layer 156 by spraying 162 the desired polymer using
polymer spray applicator 160. The woven fabric or synthetic
material reinforcing layer 154 is temporarily clamped, stapled,
tacked, glued, or otherwise temporarily positioned (not shown in
FIG. 3A) against the polymeric material 152. Polymer spray
applicator 160 is used to spray 162 the additional polymeric
material layer 156 such that the additional polymeric material
layer 156 is applied over the woven fabric or synthetic material
reinforcing layer 154, and also permeates the woven fabric or
synthetic material reinforcing layer 154 forming a chemical bond,
in one embodiment, between the polymeric material 152 and the
additional polymeric material layer 156. In one embodiment, the
polymeric material 152 and the additional polymeric material layer
156 are fabricated from the same polymer. In alternative
embodiments, the polymeric material 152 and the additional
polymeric material layer 156 are fabricated of different polymers.
The properties of polymers, however, provide for strong, permanent,
and in some cases chemical bonding between the layers, effectively
encasing the woven fabric or synthetic material reinforcing layer
154 within the bonded polymers 152, 156.
[0041] In one embodiment, the woven fabric or synthetic material
reinforcing layer 154 forms a reinforcing layer of the CMP
processing belt and therefore has the same continuous loop,
belt-shaped structure as the polymeric material 152 of the CMP
processing belt 150. As described above, the fabrication of one
embodiment of the present invention includes the temporary
application of the woven fabric or synthetic material reinforcing
layer 154 to the polymeric material 152 by such methods as
clamping, stapling, tacking, the use of adhesives, and the like. As
will be described in greater detail below in reference to FIG. 4,
the woven fabric or synthetic material reinforcing layer 154 can be
fabricated for and positioned against an interior surface of the
polymeric material 152, or the woven fabric or synthetic material
reinforcing layer 154 can be fabricated for and positioned against
an exterior surface of the polymeric material 152. As used herein,
an interior surface of the polymeric material 152 corresponds to an
interior surface of the continuous loop, belt-shaped structure
defining the CMP processing belt 150. The interior surface of the
CMP processing belt 150 is that surface in contact with the drums
104 (see FIGS. 1A and 1B) and the platen 114 (see FIGS. 1A and 1B).
The exterior surface, therefore, is that surface having a
processing surface and against which a wafer is applied for
processing.
[0042] FIG. 3B is a cross section of a CMP processing belt 150 in
accordance with an embodiment of the present invention. Similar to
the CMP processing belt 150 illustrated in FIG. 3A, the CMP
processing belt in FIG. 3B includes a polymeric material 152, a
woven fabric or synthetic material reinforcing layer 154, and an
additional polymeric material layer 156. The woven fabric or
synthetic material reinforcing layer 154 has been positioned
against the polymeric material 152, and the additional polymeric
material layer 156 has been applied over the woven fabric or
synthetic material reinforcing layer 154 by spraying 162 or
otherwise applying the additional polymeric material layer 156 such
that the applied polymer permeates the woven fabric or synthetic
material reinforcing layer 154 and forms a strong and permanent
bond between the polymeric material 152 and the additional
polymeric material layer 156, effectively encasing the woven fabric
or synthetic material reinforcing layer 154 within the CMP
processing belt 150. In some embodiments, the bond formed is a
chemical bond between the polymeric material 152 and the additional
polymeric material layer 156. The embodiment illustrated in FIG. 3B
includes an EPD opening 158, functioning as described above in
reference to FIG. 2B.
[0043] In one embodiment, the EPD opening 158 is fabricated in the
woven fabric or synthetic material reinforcing layer 154 prior to
the positioning of the woven fabric or synthetic material
reinforcing layer 154 against the polymeric material 152. After the
additional polymeric material layer 156 is applied, and the
polymeric material 152 and the additional polymeric material layer
156 are bonded encasing the woven fabric or synthetic material
reinforcing layer 154. In one embodiment, the EPD opening 158 is
fabricated in the CMP processing belt 150 by creating an opening
through the additional polymeric material layer 156 and the
polymeric material 152 aligned with and through the opening already
created in the woven fabric or synthetic material reinforcing layer
154. In some applications, a selected woven fabric or synthetic
material is tough, strong, durable, and otherwise very difficult to
cut or otherwise pierce in order to form an EPD opening. When the
woven fabric or synthetic material is encased in polymeric
material, the creation of an opening is extremely difficult, and
therefore the opening is created prior to the positioning of the
woven fabric or synthetic material reinforcing layer 154 against
the polymeric material 152.
[0044] In another embodiment, the polymeric material 152 and the
additional polymeric material layer 156 are thinned (not shown in
FIG. 3B) at the region in which the EPD opening 158 is defined
through the woven fabric or synthetic material reinforcing layer
154. In some implementations it is unnecessary to completely pierce
through all of the polymeric material 152, the woven fabric or
synthetic material reinforcing layer 154 and the additional
polymeric material layer 156. Because the woven fabric or synthetic
material reinforcing layer 156 has an EPD opening allowing for
optical transmission through the reinforcing layer, the polymeric
material 152 and the additional polymeric material layer 156 need
only be thinned to allow optical transmission for EPD.
[0045] In other embodiments, the EPD opening 158 is fabricated by
creating an opening in a fabricated CMP processing belt 150 through
each of the integral polymeric material 152, the woven fabric or
synthetic material reinforcing layer 154, and the additional
polymeric material layer 156. In an alternative embodiment, an EPD
opening 158 can be fabricated in the polymeric material 152 during
casting of the continuous loop, belt-shaped structure, and an
opening can be created in the woven fabric or synthetic material
reinforcing layer 154 prior to positioning against the polymeric
material 152 during fabrication of the CMP processing belt 150. The
openings in the component layers are aligned when the woven fabric
or synthetic material reinforcing layer 154 is positioned against
the polymeric material 152. The additional polymeric material layer
156 is applied, bonding the layers together and encasing the woven
fabric or synthetic material reinforcing layer 154 forming the CMP
processing belt 150. The EPD opening 158 is then created by
punching through the additional polymeric material layer 156 over
the openings already created in the polymeric material 152 and the
woven fabric or synthetic material reinforcing layer 154.
[0046] FIG. 4 shows a detail view of the application of the
additional polymeric material layer 156 described in reference to
FIGS. 3A and 3B in accordance with one embodiment of the invention.
As described in reference to FIGS. 3A and 3B, the woven fabric or
synthetic material reinforcing layer 154 is fabricated as a
continuous loop, belt-shaped structure, and positioned against the
polymeric material 152 which is also a continuous loop, belt-shaped
structure. The woven fabric or synthetic material reinforcing layer
154 can be positioned against either an interior surface or an
exterior surface of the polymeric material 152 according to desired
implementation and use of the CMP processing belt 150. In one
embodiment, the woven fabric or synthetic material reinforcing
layer 154 is fabricated from kevlar. In other embodiments, the
woven fabric or synthetic material reinforcing layer 154 is
fabricated of any of a plurality of fabrics or synthetic materials
including polyesters, rayon, nylon, polyimides, mixtures of
synthetics, and the like. The selected woven fabric or synthetic
material is generally porous to allow for the additional polymeric
material layer 156 to permeate the woven fabric or synthetic
material such that the polymer(s) of the polymeric material 152 and
the additional polymeric material layer 156 form a bond,
effectively encasing the woven fabric or synthetic material
reinforcing layer within the polymeric material 152 and the
additional polymeric material layer 156 defining an integral
structure CMP processing belt 150. The integral structure thus
formed is essentially not susceptible to delamination or separation
of the layers typically used in the construction of some prior art
CMP processing belts and surfaces.
[0047] As shown in FIG. 4, an embodiment of the present invention
includes the application of the additional polymeric material layer
156 by spraying 162 polymeric material with a polymer spray
applicator 160. The applied polymer or polymeric material of the
additional polymeric material layer 156 can be the same polymer or
polymeric material as that defining polymeric material 152, or in
some embodiments, it can be a different polymer or polymeric
material. In preferred embodiments, the selected polymers or
polymeric materials have properties providing for the formation of
a strong and permanent bond. In some embodiments, the bond formed
is a chemical bond. Exemplary polymeric materials include
polyurethane, polyester, PVC, polyacrylate, any of a plurality of
epoxies, and the like. As can be appreciated in FIG. 4, the applied
polymer permeates the woven fabric or synthetic material
reinforcing layer 154, forming the strong and permanent bond
between the polymeric material 152 and the additional polymeric
material layer 156, and encasing the woven fabric or synthetic
material reinforcing layer 154. The resulting structure defines a
reinforced CMP processing belt as an integrated structural
unit.
[0048] FIG. 5 shows a cross section of a CMP processing belt 170 in
accordance with another embodiment of the present invention. In the
embodiment illustrated in FIG. 5, the CMP processing belt 170
includes the polymeric material 152, the woven fabric or synthetic
material reinforcing layer 154, and the additional polymeric
material layer 156 as illustrated and described above in reference
to FIGS. 3A, 3B, and 4. A processing surface layer 172 is cast,
sprayed, or otherwise applied to the CMP processing belt 170
illustrated in FIG. 5. In the embodiments illustrated and described
in FIGS. 3A, 3B, and 4, the polymeric material 152 defines the
processing surface. In the embodiment illustrated in FIG. 5, a
separate processing surface layer 172 is cast, sprayed, or
otherwise fabricated over the polymeric material 152 to define the
processing surface for the CMP processing belt 170.
[0049] The CMP processing belt 170 illustrated in FIG. 5 is
fabricated in order to optimize the processing surface in
applications in which it is desirable to have a processing surface
layer 172 of a different hardness than underlying polymeric
material 152 or additional polymeric material layer 156. As
described above in reference to FIG. 4, the woven fabric or
synthetic material reinforcing layer 154 can be positioned against
either an interior surface of the polymeric material 152 or an
exterior surface of the polymeric material 152. In this manner,
differing hardnesses of the layers can be combined to optimize the
hardness of the processing surface layer 172 according to
processing conditions and desires. In one embodiment, the polymeric
material 152, the woven fabric or synthetic material reinforcing
layer 154 and the additional polymeric material layer 156 are
fabricated as described above in reference to FIGS. 3A, 3B, and 4,
and then the processing surface layer 172 is cast over the already
fabricated layers to define the processing surface of CMP
processing belt 170. In other embodiments, the polymeric material
152, the woven fabric or synthetic material reinforcing layer 154
and the additional polymeric material layer 156 are fabricated, and
the processing surface layer 172 is sprayed over or otherwise
applied over the fabricated layers to define the CMP processing
belt 170.
[0050] The embodiment of the CMP processing belt 170 illustrated in
FIG. 5 can also be utilized to control the thickness of the CMP
processing belt 170 to meet performance requirements. A typical CMP
processing belt 170, 150, in accordance with embodiments of the
present invention as described above, ranges in thickness from
about 80 mils to about 100 mils. In an embodiment of a CMP
processing belt 170 according to the present invention, the
thickness of the integral polymeric material 152, the woven fabric
or synthetic material reinforcing layer 154, and the additional
polymeric material layer 156 can be minimized to a range from about
20 mils to about 30 mils while retaining the desired strength and
structural support properties. The overall thickness of the CMP
processing belt 170 is then dependent upon the type and thickness
of the processing surface layer 172. By way of example, if a
thicker CMP processing belt 170 is desired, any of the polymeric
material 152, the additional polymeric material layer 156, and the
processing surface layer 172 can be fabricated to a desired
thickness to achieve design goals. In a similar manner, the
thickness and composition of the layers 172, 152, 156, can be
adjusted to achieve desired hardness, rigidity, and the like
according to processing conditions and desires.
[0051] FIG. 6 is a flow chart diagram 200 illustrating the method
operations for manufacturing a reinforced polymeric CMP processing
belt in accordance with one embodiment of the present invention.
The illustrated method begins with operation 210 in which the woven
fabric or synthetic material reinforcing layer is fabricated. In
one embodiment, the woven fabric or synthetic material reinforcing
layer is fabricated of kevlar. In other embodiments, the woven
fabric or synthetic material reinforcing layer is fabricated of
nylon, rayon, polyester, polyimide, a mixed synthetic material, or
any other desired fabric or synthetic material to provide the
desired reinforcement of the fabricated CMP processing belt.
Examples of desired reinforcement qualities include strength,
durability, a decrease in the tendency of the CMP processing belt
to stretch with continued, sustained use, flexibility for use in a
linear CMP processing tool or system, and the like.
[0052] In one embodiment, the woven fabric or synthetic material
reinforcing layer is fabricated to be positioned against an
interior surface of the polymeric material of the fabricated CMP
processing belt. In another embodiment, the woven fabric or
synthetic material reinforcing layer is fabricated to be positioned
against an exterior surface of the fabricated CMP processing belt.
In method operation 210 the woven fabric or synthetic material
reinforcing layer is fabricated according to the desired dimension
and positioning in a continuous loop, belt-like structure. In one
embodiment, EPD openings are fabricated in the woven fabric or
synthetic material reinforcing layer during fabrication of the
layer according to processing desires.
[0053] The method continues with operation 212 and the preparation
of a polymer to be molded into a CMP processing belt. In one
embodiment, a polymer or polymeric material is prepared for molding
into a polymeric CMP processing belt utilizing a polymeric mold. A
polymeric mold is typically used to cast a polymeric CMP processing
belt as a continuous loop, belt-like structure by injecting a
desired polymer or polymeric material into a mold or form of the
desired shape and dimension. In one embodiment, method operation
212 includes the preparation of the polymer or polymeric material
to be used to cast the polymeric material described above in
reference to FIGS. 3A, 3B, 4, and 5, and identified by reference
numeral 152. In one embodiment, the preparation of the polymer or
polymeric material in method operation 212 includes the preparation
for the polymeric material and for preparation of the polymer or
polymeric material for the additional polymeric material layer
described above and identified by reference numeral 156.
[0054] Any desired polymer or polymeric material may be used in
operation 212 according to the intended processing requirements.
Generally, a flexible, durable, and tough material is desired for a
linear CMP processing belt for effective wafer planarization
without scratching. The selected polymer need not be fully elastic,
and should not slacken or loosen with use. Different polymers may
be selected to enhance certain features of the intended process. In
one embodiment, the polymer may be polyurethane. In another
embodiment, the polymer may be a urethane mixture that produces a
processing surface of the completed polymeric CMP processing belt
that is a microcellular polyurethane with a specific gravity of
approximately 0.4-1.5 g/cm.sup.2 and a hardness of approximately
2.5-90 shore D. Typically, a liquid resin and a liquid curative are
combined to form the polyurethane mixture. In another embodiment, a
polymeric gel may be utilized to form the polymeric material.
[0055] After operation 212, the method proceeds to operation 214 in
which prepared polymer is injected into the mold. In one
embodiment, urethane or other polymer or polymeric material is
dispensed into a hot cylindrical mold. In one embodiment, the
injection of prepared polymer into a mold is to form the polymeric
material identified by reference numeral 152 in the Figures
described above.
[0056] In operation 216, the prepared polymer is heated and cured.
It should be understood that any type of polymer may be heated and
cured in any way that would produce the physical characteristics
desired in a finished polymeric CMP processing belt. In one
embodiment, a urethane mixture is heated and cured for a
predetermined time at a predetermined temperature to form a
urethane processing surface. Curing times and temperatures suitable
to the selected polymer or polymeric material, or to achieve
specific desired properties may be followed. In just one example,
thermoplastic materials are processed hot and then become set by
cooling.
[0057] After operation 216, the method advances to operation 218
and the polymeric material is de-molded by removing the belt from
the mold. In one embodiment, the mold is a polymeric linear CMP
processing belt molding container used to form the polymeric
material to be reinforced with the woven fabric or other synthetic
material reinforcing layer, and additional polymeric material to
encase the woven fabric or synthetic material reinforcing layer
within the polymeric structure of the CMP processing belt.
[0058] Then, in operation 220, the polymeric material is fabricated
to a desired thickness and dimension according to processing
requirements. In one embodiment, the polymeric material is lathed
to predetermined dimensions. In operation 220, the polymeric
material, in a molded continuous loop belt-shaped form, is cut to
the desired thickness and dimensions for optimal linear CMP
processing. In one embodiment, the polymeric CMP processing belt is
lathed to a thickness ranging from about 0.02 inch to about 0.2
inch, with a preferred thickness of about 0.02 inch to about 0.05
inch, according to the CMP process for which the polymeric CMP
processing belt is intended to be used.
[0059] The method proceeds with operation 222 in which the woven
fabric or synthetic material reinforcing layer is positioned
against polymeric material and temporarily attached. Methods of
temporary attachment include clamping, stapling, tacking, use of
adhesives, and the like in order to precisely position the woven
fabric or synthetic material reinforcing layer against the
polymeric material. In one embodiment, the woven fabric or
synthetic material reinforcing layer is positioned against an
interior surface of the polymeric layer. In another embodiment, the
woven fabric or synthetic material reinforcing layer is positioned
against an exterior surface of the polymeric material, according to
processing and fabrication desires.
[0060] In method operation 224, additional polymeric material is
applied to form the additional polymeric material layer and encase
the woven fabric or synthetic material reinforcing layer within the
polymeric structure of the fabricated CMP processing belt. In one
embodiment, the additional polymeric material is applied by
spraying the additional polymeric material over the woven fabric or
synthetic material reinforcing layer. In another embodiment, the
polymeric material with temporarily attached woven fabric or
synthetic material reinforcing layer is positioned in a mold and
the additional polymeric material is cast over the woven fabric or
synthetic material reinforcing layer. However the additional
polymeric material layer is applied, the polymer or polymeric
material permeates the woven fabric or synthetic material and bonds
with the polymeric material, encasing the woven fabric or synthetic
material reinforcing layer to define an integral structure of the
reinforced CMP processing belt.
[0061] The method continues with operation 226 in which the
reinforced polymeric CMP processing belt, including the polymeric
material, the woven fabric or synthetic material reinforcing layer,
and the additional polymeric material layer as an integral
structure, is fabricated into the desired thickness and dimension
for the reinforced CMP processing belt. In one embodiment, the
fabrication includes lathing, trimming, and the like to achieve the
desired thickness and surface quality. If the polymeric linear CMP
processing belt is an embodiment with EPD openings, one embodiment
of operation 226 includes piercing, thinning and clearing of the
polymeric regions at the EPD openings fabricated in the woven
fabric or synthetic material reinforcing layer as described above.
In one embodiment of fabrication of a CMP processing belt in
accordance with the present invention, the mold or form used in
method operation 214 includes structural definition of EPD openings
within the mold or form. The woven fabric or synthetic material
reinforcing layer is positioned in method operation 222 with
fabricated EPD openings aligned with the structures defined in the
polymeric material, and in operation 226, the final thinning or
piercing of the EPD openings is accomplished as desired.
[0062] In one embodiment of method operation 226, the reinforced
polymeric CMP processing belt is fabricated to a desired thickness
and dimension according to processing requirements. In one
embodiment, the integral polymeric material is lathed to
predetermined dimensions. In one embodiment, the reinforced
polymeric CMP processing belt is lathed to a thickness ranging from
about 0.02 inch to about 0.2 inch, with a preferred thickness of
about 0.07 inch to about 0.12 inch, according to the CMP process
for which the polymeric CMP processing belt is intended to be
used.
[0063] In one embodiment of method operation 226, edges of the
reinforced polymeric CMP processing belt are trimmed, and the
reinforced polymeric CMP processing belt is cleaned and prepared
for use. In one embodiment, the polymeric linear CMP processing
belt is 90-110 inches in length, 8-16 inches wide and 0.020-0.2
inches thick. It is therefore suitable for use in the Teres.TM.
linear polishing apparatus manufactured by Lam Research
Corporation.
[0064] In one embodiment, the fabrication of the integral structure
reinforced polymeric CMP processing belt to the desired thickness
and dimension completes the fabrication of a reinforced CMP
processing belt, and the method is done. In one embodiment, the
method includes additional method operation 228 in which a desired
preparation surface is fabricated. In the fabrication of the
preparation surface of method operation 228 grooves are formed on a
processing surface of the reinforced polymeric CMP processing belt
in accordance with one embodiment of the invention. In another
embodiment, the grooves may be formed during molding by providing a
suitable pattern on the inside of the mold. In one embodiment, the
raw casting is turned and grooved on a lathe to produce a smooth
polishing surface with square shaped grooves. In another
embodiment, a separate polymer or polymeric material processing
surface is applied to the reinforced CMP processing belt, the
polymer(s) or polymeric material bonding to the reinforced CMP
processing belt as an additional integral structure. Embodiments of
additional processing surfaces include surfaces providing a
different hardness than the underlying layers of the reinforced
polymeric CMP processing belt, desired surface texturing, and the
like. If the additional method operation 228 is accomplished, the
reinforced polymer CMP processing belt is completed upon
fabrication and preparation of the processing surface, and the
method is done.
[0065] Although the foregoing invention has been described in some
detail for purposes of clarity of understanding, it will be
apparent that certain changes and modifications may be practiced
within the scope of the appended claims. Accordingly, the present
embodiments are to be considered as illustrative and not
restrictive, and the invention is not to be limited to the details
given herein, but may be modified within the scope and equivalents
of the appended claims.
* * * * *