U.S. patent application number 09/734089 was filed with the patent office on 2002-06-13 for method of manufacturing a polymer or polymer/composite polishing pad.
Invention is credited to Yancey, Paul J..
Application Number | 20020069591 09/734089 |
Document ID | / |
Family ID | 22620587 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020069591 |
Kind Code |
A1 |
Yancey, Paul J. |
June 13, 2002 |
Method of manufacturing a polymer or polymer/composite polishing
pad
Abstract
Manufacture of a polishing pad for polishing a semiconductor
substrate, involves, transporting a backing layer to successive
manufacturing stations, supplying a fluid phase polymer composition
onto the transported backing layer, shaping the fluid phase polymer
composition into a surface layer having a measured thickness, and
curing the polymer composition on the transported backing layer in
a curing oven to convert the liquid phase polymer composition to a
solid phase polishing layer attached to the transported backing
layer.
Inventors: |
Yancey, Paul J.; (Charlotte,
NC) |
Correspondence
Address: |
Gerald K. Kita
Rodel Holdings, Inc.
Suite 1300
1105 North Market Street
Wilmington
DE
19899
US
|
Family ID: |
22620587 |
Appl. No.: |
09/734089 |
Filed: |
December 11, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60170610 |
Dec 14, 1999 |
|
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|
Current U.S.
Class: |
51/297 |
Current CPC
Class: |
B24D 3/28 20130101; B24D
18/009 20130101; B24D 11/001 20130101; Y10T 428/249971 20150401;
Y10T 428/249986 20150401; B24B 37/205 20130101; Y10T 428/249976
20150401; Y10T 428/249981 20150401; Y10T 428/249972 20150401; Y10T
428/249974 20150401 |
Class at
Publication: |
51/297 |
International
Class: |
B24D 011/00 |
Claims
What is claimed is:
1. A method of manufacturing a polishing pad that is used for
polishing a semiconductor substrate, comprising the steps of:
transporting a continuous material forming a transported backing
layer to successive manufacturing stations, supplying a fluid phase
polymer composition onto the transported backing layer at a first
manufacturing station, shaping the fluid phase polymer composition
on the transported backing layer into a surface layer having a
measured thickness at another manufacturing station, and curing the
polymer composition on the transported backing layer in a curing
oven to convert the polymer composition to a solid phase polymer
layer attached to the transported backing layer at another
manufacturing station, the solid phase polymer layer providing a
solid phase polishing layer of a polishing pad that is used for
polishing semiconductor substrates.
2. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with particulates to provide a solid phase polishing
layer of a fixed abrasive polishing pad.
3. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with water soluble polymeric microelements to provide a
polishing layer of a polishing pad entrained with the soluble
polymeric microelements.
4. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with polymeric microelements having polymeric shells to
provide a solid phase polishing layer of a polishing pad entrained
with the polymeric microelements.
5. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with polymeric microelements having polymeric shells
containing polishing fluid to provide a solid phase polishing layer
of a polishing pad entrained with the polymeric microelements.
6. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with abrasive particles to provide a solid phase
polishing layer of a polishing pad entrained with the abrasive
particles.
7. The method as recited in claim 1, further comprising the step
of: supplying the fluid phase polymer composition with a
constituent providing a solid phase polishing layer having
pores.
8. The method as recited in claim 1, and further comprising the
step of: surface finishing the solid phase polymer composition and
the backing layer with a rotating milling head.
9. The method as recited in claim 1, and further comprising the
step of: stamping the solid phase polymer composition and the
backing layer between a pair of compression forming dies.
10. The method as recited in claim 1, and further comprising the
step of: puncturing hollow shells in the solid phase polymer
composition by stamping the solid phase polymer composition and the
backing layer between a pair of compression forming dies.
11. A method of manufacturing a polishing pad that is used for
polishing a semiconductor substrate, comprising the steps of:
supplying a fluid phase polymer composition onto a continuous
transported backing layer, shaping the fluid phase polymer
composition on the transported backing layer into a surface layer
having a measured thickness, and curing the polymer composition on
the transported backing layer in a curing oven to convert the
polymer composition to a solid phase polishing layer of a polishing
pad that is used for polishing semiconductor substrates.
12. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with particulates to provide a solid phase polishing
layer of a fixed abrasive polishing pad.
13. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with water soluble polymeric microelements to provide a
polishing layer of a polishing pad entrained with the soluble
polymeric microelements.
14. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with polymeric microelements having polymeric shells to
provide a solid phase polishing layer of a polishing pad entrained
with the polymeric microelements.
15. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with polymeric microelements having polymeric shells
containing polishing fluid to provide a solid phase polishing layer
of a polishing pad entrained with the polymeric microelements.
16. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition as a matrix
entrained with abrasive particles to provide a solid phase
polishing layer of a polishing pad entrained with the abrasive
particles.
17. The method as recited in claim 11, further comprising the step
of: supplying the fluid phase polymer composition with a
constituent providing a solid phase polishing layer having
pores.
18. The method as recited in claim 11, and further comprising the
step of: surface finishing the solid phase polymer composition and
the backing layer with a rotating milling head.
19. The method as recited in claim 11, and further comprising the
step of: stamping the solid phase polymer composition and the
backing layer between a pair of compression forming dies.
20. The method as recited in claim 11, and further comprising the
step of: providing surface asperities in the solid phase polymer
composition by stamping the solid phase polymer composition and the
backing layer between a pair of compression forming dies.
21. The method as recited in claim 11, and further comprising the
step of: puncturing hollow shells in the solid phase polymer
composition by stamping the solid phase polymer composition and the
backing layer between a pair of compression forming dies.
22. The method as recited in claim 11, and further comprising the
step of: puncturing hollow shells in the solid phase polymer
composition by buffing the solid phase polymer composition.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Provisional
Application No. 60/170,610 filed Dec. 14, 1999.
FIELD OF THE INVENTION
[0002] The invention relates to manufacture of a polymer based
polishing pad, particularly a polishing pad used for polishing
semiconductor substrates.
BACKGROUND OF THE RELATED ART
[0003] U.S. Pat. No. 6,099,954 discloses a known method of
manufacturing a polishing pad for polishing semiconductor
substrates, includes the step of; coagulating a layer of viscous
polishing material in-situ, meaning, directly onto, a portion of
the manufactured polishing pad. The polishing material is an
elastomer or polymer that is coagulated and dried, in situ, on a
backing layer in sheet form. The polishing material solidifies and
adheres to the backing layer. Prior to the invention, batch
processing was performed to manufacture a limited number of
polishing pads. The polishing pads that were manufactured by one
batch processing varied from those manufactured by another batch
processing. A need exists for a manufacturing process that avoids
variations in polishing pads that are manufactured according to
different batches.
SUMMARY OF THE INVENTION
[0004] The invention provides a continuous manufacturing process,
which eliminates batch processing and reduces variations among
polishing pads that are manufactured according to different
batches. A method of manufacturing a polishing pad that is used for
polishing a semiconductor substrate, comprises the steps of;
transporting a continuous material forming a transported backing
layer through successive manufacturing stations, supplying a fluid
phase polymer composition onto the transported backing layer,
shaping the polymer composition on the transported backing layer
into a surface layer having a measured thickness, curing the
polymer composition on the transported backing material in a curing
oven to convert the polymer composition to a solid phase polymer
layer attached to the transported backing layer, the solid phase
polymer layer providing a solid phase polishing layer of a
polishing pad that is used for polishing semiconductor
substrates.
DESCRIPTION OF THE DRAWINGS
[0005] Embodiments of the invention will now be described by way of
example with reference to the drawings, according to which:
[0006] FIG. 1 is a diagrammatic view of apparatus for continuous
manufacturing of a continuous form of a polishing pad used for
polishing semiconductor substrates;
[0007] FIG. 1A is a diagrammatic view of a take up reel on which is
wound a continuous polishing pad;
[0008] FIG. 2 is a diagrammatic view of apparatus for continuous
conditioning of a continuous polishing pad used for polishing
semiconductor substrates;
[0009] FIG. 3 is a fragmentary cross section of a polishing pad
manufactured according to the apparatus disclosed by FIG. 1;
[0010] FIG. 3A is a view similar to FIG. 3, and disclosing another
polishing pad manufactured according to the apparatus disclosed by
FIG. 1; and
[0011] FIG. 3B is a view similar to FIG. 3, and disclosing another
polishing pad manufactured according to the apparatus disclosed by
FIG. 1.
DETAILED DESCRIPTION
[0012] FIG. 3 discloses a portion of a polishing pad (300) of a
type having a backing layer (302) to which is adhered, or otherwise
attached, an overlying polishing layer (304). Without abrasive
particles in the polishing layer (304), the polishing pad (300) is
known as an abrasive free pad. According to another embodiment, the
polishing pad (300) becomes a fixed abrasive pad entrained with
distributed, abrasive particles or particulates (306) in the
polishing layer (304). The abrasive free pad is disclosed by FIG.
3, by visualization of the polishing layer (304) without the
abrasive particles or particulates (306) therein.
[0013] FIG. 3A discloses a portion of another embodiment of a
polishing pad (300) having the backing layer (302) and the
polishing layer (304). The polishing layer (302) is entrained with
distributed open pores (308) therethrough.
[0014] FIG. 3B discloses a portion of another embodiment of a
polishing pad (300) having the backing layer (302) and the
polishing layer (304). The polishing layer (302) is entrained with
distributed microelements in the form of hollow shells (310)
therethrough. The hollow shells (310) are gas filled, for example,
air at atmospheric pressure or greater pressure. Alternatively, the
hollow shells (310) are filled with a known polishing fluid that is
released by fracture or puncture of the hollow shells (310) during
a polishing operation known as CMP, chemical mechanical
planarization. The CMP polishing operation uses the polishing pad
(300) for polishing semiconductor substrates. The known polishing
fluid is released at an interface of the polishing pad (300) and
the semiconductor substrate that is being polished.
[0015] FIG. 1 discloses apparatus (100) for continuous
manufacturing of a polishing pad (300) in continuous form.
Continuous manufacturing replaces batch processing. Continuous
manufacturing reduces variations among different polishing pads
(300) that are caused by batch processing. The apparatus (100)
includes a feed reel (102) on which is stored a helically wrapped
backing layer (302) in lengthwise continuous form. The backing
layer (302) is of nonwoven fiberous material or, alternatively, of
an impermeable membrane, such as, a polyester film. The feed roller
(102) is mechanically driven to rotate at a controlled speed by a
drive mechanism (104). The drive mechanism (104), for example, is
disclosed as a belt (106) and motor driven pulley (108), and
alternatively includes, for example, a motor driven flexible shaft
or a motor driven gear train.
[0016] FIG. 1 discloses the continuous backing layer (302) being
supplied by the feed reel (102) onto a continuous conveyor (110),
for example, a stainless steel belt, that is looped over spaced
apart drive rollers (112). The drive rollers (112) are motor driven
at a speed that synchronizes linear travel of the conveyor (110)
with that of the continuous backing layer (302). The backing layer
(302) is transported by and against the conveyor (110) along a
space between each drive roller (112) and a corresponding idler
roller (112a). The idler roller (112a) engages the backing layer
(302) for positive tracking control of the conveyor (110) and the
backing layer (302). The conveyor (110) has a flat section (110a)
supported on a flat and level surface of a table support (110b),
which flatly supports the backing layer (302) and transports the
backing layer (302) through successive manufacturing stations
(114), (122) and (126). Support members (110c) in the form of
rollers are distributed along the lateral edges of the conveyor
(110) and the backing layer (302) for positive tracking control of
the conveyor (110) and the backing layer (302).
[0017] A first manufacturing station (114) includes a storage tank
(116) and a nozzle (118) at an outlet of the tank (116). A viscous,
fluid state polymer composition is supplied to the tank (116), and
is dispensed by the nozzle (118) onto the continuous backing layer
(302). The flow rate of the nozzle (118) is controlled by a pump
(120) at the outlet of the tank (116). The nozzle (118) is as wide
as the width of the continuous backing layer (302) to cover the
backing layer (302) with the polishing layer (304) comprised of the
fluid state polymer composition. As the conveyor (110) transports
the continuous backing layer (302) past the manufacturing station
(114), a continuous, fluid phase polishing layer (304) is supplied
onto the backing layer (302).
[0018] A second manufacturing station (122) includes a doctor blade
(124) located at a precise distance from the continuous backing
layer (302) defining a clearance space therebetween. As the
conveyor (110) transports the continuous backing layer (302) and
the fluid phase polishing layer (304) past the doctor blade (124)
of the manufacturing station (122), the doctor blade (124)
continuously shapes the fluid phase polishing layer (304) to a
precise thickness.
[0019] A third manufacturing station (126) includes a curing oven
(128) in the form of a heated tunnel through which is transported
the continuous backing layer (302) and the polishing layer (304) of
precise thickness. The oven (128) cures the fluid phase polishing
layer (304) to a continuous, solid phase polishing layer (304) that
adheres to the continuous backing layer (302). The cure time is
controlled by temperature and the velocity of transport through the
oven (128). The oven (128) is fuel fired or electrically fired,
using either radiant heating or forced convection heating, or
both.
[0020] Upon exiting the oven (128), the continuous backing layer
(302) is adhered to a continuous, solid phase polishing layer (304)
to comprise, a continuous polishing pad (300). The continuous
polishing pad (300) is rolled helically onto a take up reel (130),
FIG. 1A, that successively follows the manufacturing station (126).
The take up reel (130) is driven by a second drive mechanism (104).
The take up reel (130) and second drive mechanism (104) comprise, a
separate manufacturing station that is positioned selectively in
the manufacturing apparatus (100).
[0021] According to an embodiment of the polishing pad (300) as
disclosed by FIG. 3, a high solids constituent in a viscous, fluid
state polymer mixture, for example, a latex polymer mixture or a
polyurethane polymer mixture, is supplied by the tank (116).
According to another embodiment, the polymer mixture includes a
constituent that is transparent to a beam of electromagnetic
radiation in a wavelength range of about 190 nanometers to about
3500 nanometers for optical monitoring and detection. Upon curing
in the oven (128), the polymer mixture forms a solidified,
continuous polishing pad (300). Without the abrasive particles or
particulates (306) added to the fluid state polymer mixture, the
continuous polishing pad (300) is an abrasive free polishing pad
(300).
[0022] According to another embodiment, the abrasive particles or
particulates (306) are included as a constituent in the fluid state
polymer mixture. The polymer mixture becomes a matrix that is
entrained with the abrasive particles or particulates (306). The
continuous polishing pad (300) becomes a fixed abrasive polishing
pad (300) having the abrasive particles or particulates (306)
distributed throughout the continuous polishing layer (304).
[0023] According to an embodiment of the polishing pad (300) as
disclosed by FIG. 3A, an entrained constituent in the form of, a
foaming agent or blowing agent or a gas, is included in the polymer
mixture that serves as a matrix that is entrained with the
constituent. Upon curing, the foaming agent or blowing agent or gas
escapes as volatiles to provide the open pores (308) distributed
throughout the continuous polishing layer (304).
[0024] According to an embodiment of the polishing pad (300) as
disclosed by FIG. 3B, an entrained constituent in the form of
microballons or polymeric hollow shells (310) are included in the
polymer mixture, and become distributed throughout the continuous
polishing layer (304). The shells (310) are gas filled.
Alternatively the shells (310) are filled with a polishing fluid
that is dispensed when the shells (310) are opened by abrasion or
by fracture or by puncture when the polishing pad (300) is used
during a polishing operation known as CMP. Alternatively, the
shells (310) are water soluble polymeric microelements that are
opened by becoming soluble in water during a polishing operation
known as CMP.
[0025] Prior to the invention, a batch process method for making
latex based polishing pads involved, placing high solids latex
polymer mix in a mold, placing the mold in an oven, and then curing
the pad in the mold in the oven. Batch processes for making pads
resulted in variations in the pads, due to the batch and position
variability seen in the batch processes.
[0026] FIG. 2 discloses additional apparatus (200) for surface
conditioning or surface finishing of the continuous polishing pad
(300). The apparatus (200) includes either a similar conveyor (110)
as that disclosed by FIG. 1, or a lengthened section of the same
conveyor (110), as disclosed by FIG. 1. The conveyor (110) of
apparatus (200) has a drive roller (112), and a flat section (110a)
supporting the continuous polishing pad (300) that has exited the
oven (126). The conveyor (110) of apparatus (200) transports the
continuous polishing pad (300) through one, or more than one,
manufacturing station (201), (208) and (212), at which the
continuous polishing pad (300) is further processed subsequent to
curing in the oven (126). The apparatus (200) is disclosed with
additional flat table supports (110b) and additional support
members (110c), all of which operate as disclosed with reference to
FIG. 1.
[0027] The solidified polishing layer (304) is buffed to expose a
desired surface finish and planar surface level of the polishing
layer (304). Asperities in the form of grooves or other
indentations, are worked into the surface of the polishing layer
(304). For example, a work station (201) includes a pair of
compression forming, stamping dies having a reciprocating stamping
die (202) and a fixed die (204) that close toward each other during
a stamping operation. The reciprocating die (202) faces toward the
surface of the continuous polishing layer (304). Multiple teeth
(206) on the die (202) penetrate the surface of the continuous
polishing layer (304). The stamping operation provides a surface
finishing operation. For example, the teeth (206) indents a pattern
of grooves in the surface of the polishing layer (304). Further,
for example, the teeth (206) puncture the microballons or hollow
shells (310), if any are present in the polymer mixture, at the
surface of the continuous polishing layer (304). The conveyor (110)
is intermittently paused, and becomes stationary when the dies
(202) and (204) close toward each other. Alternatively, the dies
(202) and (204) move in synchronization with the conveyor (110) in
the direction of transport during the time when the dies (202) and
(204) close toward each other.
[0028] Another manufacturing station (208) includes a rotary saw
(210) for cutting grooves in the surface of the continuous
polishing layer (304). The saw (210) is moved by a known orthogonal
motion plotter along a predetermined path to cut the grooves in a
desired pattern of grooves.
[0029] Another manufacturing station (212) includes a rotating
milling head (214) for buffing or milling the surface of the
continuous polishing layer (304) to a flat, planar surface with a
desired surface finish that is selectively roughened or smoothed.
Further, for example, the milling head (214) punctures the
microballons or hollow shells (310), if any are present in the
polymer mixture, at the surface of the continuous polishing layer
(304).
[0030] The sequence of the manufacturing stations (202), (210) and
(212) can vary from the sequence as disclosed by FIG. 2. One or
more than one of the manufacturing stations (202), (210) and (212)
can be eliminated as desired. The take up reel (130) and second
drive mechanism (104) comprise, a separate manufacturing station
that is positioned selectively in the manufacturing apparatus (200)
at the end of the conveyor (110) to wrap the solid phase continuous
polishing pad (300).
[0031] The process is adapted to curing system of a polymer liquid
phase to solid phase, according to which a viscous, moldable
polymer mixture of the mixture constituents is made. Even a polymer
mixture that does not involve a solvent based intermediate step,
such as an injection molded polymer mixture, is adapted for the
disclosed process by, first, grinding the polymer components to
extremely small sizes, dispersing the ground components in a
concentrated liquid dispersion, desicating, and then melting the
ground components in the oven (128) to coalesce the ground
components.
[0032] Because the raw materials can be mixed in large homogeneous
supply that repeatedly fills the tank (116), variations in
composition and properties of the finished product are minimized.
The continuous nature of the process enables precise control for
manufacturing a continuous polishing pad (300) from which large
numbers of individual polishing pads (300) are cut to a desired
area pattern and size. The large numbers of individual polishing
pads (300) have minimized variations in composition and
properties.
* * * * *