U.S. patent application number 09/957112 was filed with the patent office on 2002-02-07 for web-format planarizing machines and methods for planarizing microelectronic substrate assemblies.
Invention is credited to Moore, Scott E., Walker, Michael A..
Application Number | 20020016138 09/957112 |
Document ID | / |
Family ID | 23523689 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020016138 |
Kind Code |
A1 |
Walker, Michael A. ; et
al. |
February 7, 2002 |
Web-format planarizing machines and methods for planarizing
microelectronic substrate assemblies
Abstract
Methods and machines for planarizing microelectronic substrate
assemblies using mechanical and/or chemical-mechanical planarizing
processes. One machine in accordance with an embodiment of the
invention includes a table having a support surface with a
planarizing zone, an elongated polishing pad configured to move
across the support surface of the table along a pad travel path,
and a pad advancing mechanism coupled to the pad. The elongated pad
can have a length along an elongated dimension extending along the
pad travel path, an elongated first edge, an elongated second edge
opposite the first edge, an elongated first side region extending
along the first edge, an elongated second side region extending
along the second edge, and an elongated medial region having a
width between the first and second side regions. The pad advancing
mechanism can include a first roller about which an unused portion
of the pad is wrapped and a second roller about which a used
portion of the pad is wrapped. The planarizing machine can further
include a carrier assembly having a head and a drive system to
translate the substrate assembly across an active section of the
polishing pad in the planarizing zone. The planarizing machine
further includes a pad tensioning system between the planarizing
zone of the table and either the first roller or the second roller.
The tensioning system, for example, can have a pneumatic or
mechanical stretching assembly configured to push or pull the
medial region of the pad more than the first and second side
regions to compensate for the smaller diameter of the used portion
of the pad wrapped around the second roller.
Inventors: |
Walker, Michael A.; (Boise,
ID) ; Moore, Scott E.; (Meridian, ID) |
Correspondence
Address: |
Mark W. Roberts, Esq.
DORSEY & WHITNEY LLP
1420 Fifth Avenue, Suite 3400
Seattle
WA
98101
US
|
Family ID: |
23523689 |
Appl. No.: |
09/957112 |
Filed: |
September 19, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09957112 |
Sep 19, 2001 |
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09907834 |
Jul 17, 2001 |
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09907834 |
Jul 17, 2001 |
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09385985 |
Aug 30, 1999 |
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6261163 |
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Current U.S.
Class: |
451/41 |
Current CPC
Class: |
B24B 21/04 20130101;
B24B 21/20 20130101; B24B 37/26 20130101; B24B 37/20 20130101 |
Class at
Publication: |
451/41 |
International
Class: |
B24B 007/22 |
Claims
1. A web-format planarizing machine for mechanical and/or
chemical-mechanical planarization of microelectronic substrate
assemblies, comprising: a table having a support surface with a
planarizing zone; an elongated polishing pad including an elongated
first edge, an elongated second edge opposite the first edge, an
elongated first side region extending along the first edge, an
elongated second side region extending along the second edge, and
an elongated medial region having a width between the first and
second side regions; a pad advancing mechanism coupled to the pad,
the pad advancing mechanism including a first roller about which an
unused portion of the pad is wrapped and a second roller about
which a used portion of the pad is wrapped; a carrier assembly
having a head configured to hold a microelectronic substrate
assembly and a drive system to move the head and translate the
substrate assembly across an active section of the polishing pad in
the planarizing zone; and a pad tensioning system between the
planarizing zone of the table and either the first roller or the
second roller, the tensioning system including an engagement member
aligned with the medial region of the pad and an actuator connected
to engagement member, the engagement member extending transverse to
the edges of the pad and having a length approximately equal to the
width of the medial region, and the actuator moving the engagement
member transverse to the pad to press the engagement member against
the medial region of the pad:
2. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises an elongated
inflatable bladder in the recess of the tensioning site and the
actuator comprises a fluid pump operatively coupled to the bladder,
the fluid pump adjusting a fluid pressure in the bladder to
selectively press the bladder against a backside of the pad.
3. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having at least one fluid port under a
section of the used portion of the pad between the second end of
the support region and the second roller, the fluid port being
aligned with the medial region of the pad; and the engagement
member comprises a flexible diaphragm over the fluid port and the
actuator comprises a fluid pump operatively coupled to the fluid
port, the actuator adjusting a fluid pressure against the diaphragm
to selectively press the diaphragm against a backside of the
pad.
4. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
and the actuator comprises a fluid piston coupled to the push-plate
to selectively move the push-plate against a backside of the
pad.
5. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
the push-plate having a compressible contact member contacting the
pad and a rigid back-plate attached to the contact member, and the
actuator comprises a fluid piston coupled to the rigid back-plate
of the push-plate to selectively move the contact member against a
backside of the pad.
6. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side 6f
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
the push-plate being curved to have an apex at approximately a
midpoint of the medial region, and the actuator comprises a fluid
piston coupled to the push-plate to selectively move the push-plate
against a backside of the pad.
7. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a flexible push-plate
at the tensioning site under a section of the used portion of the
pad between the second end of the support region and the second
roller, and the actuator comprises a fluid piston coupled to the
push-plate to selectively move the push-plate against a backside of
the pad.
8. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises an elongated
roller at least partially in the recess of the tensioning site so
that a portion of the roller projects from the recess and contacts
a backside of the pad, and the actuator comprises a fluid piston
attached to the roller for moving the roller into or out of the
recess to selectively press the roller against a backside of the
pad.
9. The machine of claim 1 wherein: the support surface of the table
has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises a rigid
roller and a toroidal inflatable bladder around the roller, the
roller being in the recess so that a portion of the toroidal
bladder projects out of the recess and contacts a backside of the
polishing pad, and the actuator comprising a fluid pump coupled to
the toroidal bladder, the fluid pump adjusting a fluid pressure in
the toroidal bladder to selectively press the bladder against the
backside of the pad.
10. A web-format planarizing machine for mechanical and/or
chemical-mechanical planarization of microelectronic substrate
assemblies, comprising: a table having a support surface with a
planarizing zone; an elongated polishing pad having a length along
an elongated dimension sufficient to extend across the table, the
pad being configured to move across the support surface of the
table along a pad travel path corresponding to the elongated
dimension, and the pad including an elongated first edge, an
elongated second edge opposite the first edge, an elongated first
side region extending along the first edge, an elongated second
side region extending along the second edge, and an elongated
medial region between the first and second side regions; a pad
advancing mechanism coupled to the pad, the pad advancing mechanism
including a first roller about which an unused portion of the pad
is wrapped and a second roller about which a used portion of the
pad is wrapped, at least one of the rollers being driven to advance
the pad across the table along the pad travel path for positioning
a desired active section of the pad in the planarizing zone; a
carrier assembly having a head and a drive system, the head being
configured to hold a microelectronic substrate assembly and the
drive system moving the head to translate the substrate assembly
across the active section of the polishing pad in the planarizing
zone; and a pad tensioning system between the planarizing zone of
the table and either the first roller or the second roller, the
tensioning system including an engagement member at the medial
region of the pad and an actuator coupled to the engagement member,
the engagement member extending transverse to the edges of the pad
and having a length less than a widthwise dimension of the pad, and
the actuator moving the engagement member to press the engagement
member against the medial region of the pad and stretch the medial
region of the pad more than the first and second side regions.
11. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning
site-between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises an elongated
inflatable bladder in the recess of the tensioning site and the
actuator comprises a fluid pump operatively coupled to the bladder,
the fluid pump adjusting a fluid pressure in the bladder to
selectively press the bladder against a backside of the pad.
12. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having at least one fluid port under a
section of the used portion of the pad between the second end of
the support region and the second roller, the fluid port being
aligned with the medial region of the pad; and the engagement
member comprises a flexible diaphragm over the fluid port and the
actuator comprises a fluid pump operatively coupled to the fluid
port, the actuator adjusting a fluid pressure against the diaphragm
to selectively press the diaphragm against a backside of the
pad.
13. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
and the actuator comprises a fluid piston coupled to the push-plate
to selectively move the push-plate against a backside of the
pad.
14. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
the push-plate having a compressible contact member contacting the
pad and a rigid back-plate attached to the contact member, and the
actuator comprises a fluid piston coupled to the rigid back-plate
of the push-plate to selectively move the contact member against a
backside of the pad.
15. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a push-plate at the
tensioning site under a section of the used portion of the pad
between the second end of the support region and the second roller,
the push-plate being curved to have an apex at approximately a
midpoint of the medial region, and the actuator comprises a fluid
piston coupled to the push-plate to selectively move the push-plate
against a backside of the pad.
16. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the engagement member comprises a flexible push-plate
at the tensioning site under a section of the used portion of the
pad between the second end of the support region and the second
roller, and the actuator comprises a fluid piston coupled to the
push-plate to selectively move the push-plate against a backside of
the pad.
17. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises an elongated
roller at least partially in the recess of the tensioning site so
that a portion of the roller projects from the recess and contacts
a backside of the pad, the actuator comprises a fluid piston
attached to the roller for moving the roller into or out of the
recess to selectively press the roller against a backside of the
pad.
18. The machine of claim 10 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the engagement member comprises a rigid
roller and a toroidal inflatable bladder around the roller, the
roller being in the recess so that a portion of the toroidal
bladder projects out of the recess and contacts a backside of the
polishing pad, and the actuator comprises a fluid pump coupled to
the toroidal bladder, the fluid pump adjusting a fluid pressure in
the toroidal bladder to selectively press the bladder against the
backside of the pad.
19. A web-format planarizing machine for mechanical and/or
chemical-mechanical planarization of microelectronic substrate
assemblies, comprising: a table having a support surface with a
planarizing zone; an elongated polishing pad including an elongated
first edge, an elongated second edge opposite the first edge, an
elongated first side region extending along the first edge, an
elongated second side region extending along the second edge, and a
medial region between the first and second side regions; a pad
advancing mechanism coupled to the pad, the pad advancing mechanism
including a first roller about which an unused portion of the pad
is wrapped and a second roller about which a used portion of the
pad is wrapped; a carrier assembly having a head configured to hold
a microelectronic substrate assembly and a drive system to move the
head to rub the substrate assembly against an active section of the
polishing pad in the planarizing zone; and a pad tensioning system
between the planarizing zone of the table and either the first
roller or the second roller, the tensioning system including a
pneumatic or mechanical stretching assembly configured to act
against the medial region of the pad and pull or push the medial
region of the pad more than first and second side regions of the
pad.
20. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the stretching assembly comprises an
engagement member comprising an elongated inflatable bladder in the
recess of the tensioning site and an actuator comprising a fluid
pump operatively coupled to the bladder, the fluid pump adjusting a
fluid pressure in the bladder to selectively press the bladder
against a backside of the pad.
21. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having at least one fluid port under a
section of the used portion of the pad between the second end of
the support region and the second roller, the fluid port being
aligned with the medial region of the pad; and the stretching
assembly comprises an engagement member comprising a flexible
diaphragm over the fluid port and an actuator comprising a fluid
pump operatively coupled to the fluid port, the actuator adjusting
a fluid pressure against the diaphragm to selectively press the
diaphragm against a backside of the pad.
22. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the stretching assembly comprises an engagement member
including a push-plate at the tensioning site under a section of
the used portion of the pad between the second end of the support
region and the second roller, and the stretching assembly further
comprises an actuator having a fluid piston coupled to the
push-plate to selectively move the push-plate against a backside of
the pad.
23. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the stretching assembly comprises an engagement member
comprising a push-plate at the tensioning site under a section of
the used portion of the pad between the second end of the support
region and the second roller, the push-plate having a compressible
contact member contacting the pad and a rigid back-plate attached
to the contact member, and the stretching assembly further
comprises an actuator having a fluid piston coupled to the rigid
back-plate of the push-plate to selectively move the contact member
against a backside of the pad.
24. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the stretching assembly comprises an engagement member
comprising a push-plate at the tensioning site under a section of
the used portion of the pad between the second end of the support
region and the second roller, the push-plate being curved to have
an apex at approximately a midpoint of the medial region, and the
stretching assembly further comprises an actuator having a fluid
piston coupled to the push-plate to selectively move the push-plate
against a backside of the pad.
25. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site being aligned with the medial region of
the pad; and the stretching assembly comprises an engagement member
including a flexible push-plate at the tensioning site under a
section of the used portion of the pad between the second end of
the support region and the second roller, and the stretching
assembly further comprises an actuator having a fluid piston
coupled to the push-plate to selectively move the push-plate
against a backside of the pad.
26. The machine of claim 1 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the stretching assembly comprises an
engagement member including an elongated roller at least partially
in the recess of the tensioning site so that a portion of the
roller projects from the recess and contacts a backside of the pad,
and the stretching assembly further comprises an actuator having a
fluid piston attached to the roller for moving the roller into or
out of the recess to selectively press the roller against a
backside of the pad.
27. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the stretching assembly comprises an
engagement member comprising a rigid roller and a toroidal
inflatable bladder around the roller, the roller being in the
recess so that a portion of the toroidal bladder projects out of
the recess and contacts a backside of the polishing pad, and the
stretching assembly further comprises an actuator having a fluid
pump coupled to the toroidal bladder, the fluid pump adjusting a
fluid pressure in the toroidal bladder to selectively press the
bladder against the backside of the pad.
28. The machine of claim 19 wherein: the support surface of the
table has a first end at one side of the planarizing zone under the
unused portion of the pad and a second end at an opposing side of
the planarizing zone under the used portion of the pad; the second
roller is below the support surface and the used portion of the pad
extends downwardly from the second end of the support surface to
the second roller; the table further comprises a tensioning site
between the second end of the support surface and the second
roller, the tensioning site having an elongated recess under a
section of the used portion of the pad, the recess being aligned
with the medial region of the pad and extending transverse to the
edges of the pad; and the stretching assembly comprises an orifice
in the recess at the tensioning site and a vacuum pump coupled to
the orifice, the pump drawing a vacuum in the recess to draw a
portion of the medial region of the pad into the recess and
selectively stretch the medial region of the pad.
29. A method of planarizing a microelectronic substrate assembly on
a planarizing machine, comprising: pressing a microelectronic
substrate assembly against a polishing pad having an elongated
first side region along an elongated first edge of the pad, an
elongated second side region along an elongated second edge of the
pad opposite the first edge, and an elongated medial region having
a width between the first and second side regions; moving the
substrate assembly and/or the polishing pad relative to the other
to move the substrate assembly across the polishing pad; and
stretching a portion of the medial region of the pad more than the
first and second side regions.
30. The method of claim 29 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone,
the pad advancing mechanism being coupled to the pad, the pad
advancing mechanism including a first roller about which an unused
portion of the pad is wrapped and a second roller about which a
used portion of the pad is wrapped, at least one of the rollers
being driven to advance the pad across the table along a pad travel
path for positioning a desired active section of the pad in the
planarizing zone, and the pad tensioning system being between the
planarizing zone of the table and either the first roller or the
second roller, the tensioning system including a pneumatic or
mechanical stretching assembly configured to act against the medial
region of the pad; and stretching a portion of the medial region of
the pad more than the first and second side regions comprises
pushing the medial region of the pad away from the table at a
tensioning site between the planarizing zone and the second
roller.
31. The method of claim 29 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone,
the pad advancing mechanism being coupled to the pad, the pad
advancing mechanism including a first roller about which an unused
portion of the pad is wrapped and a second roller about which a
used portion of the pad is wrapped, at least one of the rollers
being driven to advance the pad across the table along a pad travel
path for positioning a desired active section of the pad in the
planarizing zone, and the pad tensioning system being between the
planarizing zone of the table and either the first roller or the
second roller, the tensioning system including a pneumatic or
mechanical stretching assembly configured to act against the medial
region of the pad; and stretching a portion of the medial region of
the pad more than the first and second side regions comprises
pulling a section of the medial region of the pad into an elongated
recess in the table at a tensioning site between the planarizing
zone and the second roller, the recess being aligned with the
medial region of the pad and extending transverse to the edges of
the pad.
32. A method of planarizing a microelectronic substrate assembly on
a planarizing machine, comprising: pressing a microelectronic
substrate assembly against a polishing pad having an elongated
first side region along an elongated first edge of the pad, an
elongated second side region along an elongated second edge of the
pad opposite the first edge, and an elongated medial region having
a width between the first and second side regions; moving the
substrate assembly and/or the polishing pad relative to the other
to move the substrate assembly across the polishing pad; and
pressing an engagement member against a backside of the pad to
stretch a portion of the medial region of the pad outwardly from a
planarizing table supporting the pad more than the first and second
side regions.
33. The method of claim 32 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone
and a recess aligned with the medial region of the pad and
extending transversely to the edges of the pad, the pad advancing
mechanism being coupled to the pad, the pad advancing mechanism
including a first roller about which an unused portion of the pad
is wrapped and a second roller about which a used portion of the
pad is wrapped, at least one of the rollers being driven to advance
the pad across the table along a pad travel path for positioning a
desired active section of the pad in the planarizing zone, and the
pad tensioning system including an inflatable bladder in the recess
and a fluid pump coupled to the inflatable bladder, the inflatable
bladder defining the engagement member and the pump defining an
actuator, the recess and the inflatable bladder being at a
tensioning site between the planarizing zone and the second roller;
and pressing an engagement member against a backside of the pad
comprises operating the pump to inflate or deflate the bladder.
34. The method of claim 32 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone
and a fluid port aligned with the medial region of the pad, the pad
advancing mechanism being coupled to the pad, the pad advancing
mechanism including a first roller about which an unused portion of
the pad is wrapped and a second roller about which a used portion
of the pad is wrapped, at least one of the rollers being driven to
advance the pad across the table along a pad travel path for
positioning a desired active section of the pad in the planarizing
zone, and the pad tensioning system including a diaphragm attached
to the table over the fluid port and a fluid pump coupled to the
fluid port, the diaphragm defining the engagement member and the
pump defining an actuator, the fluid port and the diaphragm being
at a tensioning site between the planarizing zone and the second
roller; and pressing an engagement member against a backside of the
pad comprises operating the pump to inflate or deflate the
diaphragm.
35. The method of claim 32 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone
and a tensioning site aligned with the medial region of the pad,
the pad advancing mechanism being coupled to the pad, the pad
advancing mechanism including a first roller about which an unused
portion of the pad is wrapped and a second roller about which a
used portion of the pad is wrapped, at least one of the rollers
being driven to advance the pad across the table along a pad travel
path for positioning a desired active section of the pad in the
planarizing zone, and the pad tensioning system including an
push-plate at the tensioning site under a section of the used
portion of the pad between the second end of the support surface
and the second roller and an actuator having a fluid piston coupled
to the push-plate to selectively move the push-plate against the
backside of the pad, the push-plate defining the engagement member;
and pressing an engagement member against a backside of the pad
comprises extending the piston to drive the push-plate against the
backside of the pad.
36. The method of claim 32 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone
and a recess aligned with the medial region of the pad and
extending transversely to the edges of the pad, the pad advancing
mechanism being coupled to the pad, the pad advancing mechanism
including a first roller about which an unused portion of the pad
is wrapped and a second roller about which a used portion of the
pad is wrapped, at least one of the rollers being driven to advance
the pad across the table along a pad travel path for positioning a
desired active section of the pad in the planarizing zone, and the
pad tensioning system including a roller at least partially in the
recess and an actuator having a fluid piston coupled to the roller,
the roller defining the engagement member, the recess and the
roller being at a tensioning site between the planarizing zone and
the second roller; and pressing an engagement member against a
backside of the pad comprises extending the piston to drive the
roller against the backside of the pad.
37. The method of claim 32 wherein: the planarizing machine
comprises a table, a pad advancing mechanism and a pad tensioning
system, the table having a support surface with a planarizing zone
and a recess aligned with the medial region of the pad and
extending transversely to the edges of the pad, the pad advancing
mechanism being coupled to the pad, the pad advancing mechanism
including a first roller about which an unused portion of the pad
is wrapped and a second roller about which a used portion of the
pad is wrapped, at least one of the rollers being driven to advance
the pad across the table along a pad travel path for positioning a
desired active section of the pad in the planarizing zone, and the
pad tensioning system including a spindle, a toroidal bladder
around the spindle, and a fluid pump coupled to the toroidal
bladder, the toroidal bladder defining the engagement member and
the pump defining an actuator, the toroidal bladder being at least
partially in the recess at a tensioning site between the
planarizing zone and the second roller; and pressing an engagement
member against a backside of the pad comprises operating the pump
to inflate or deflate the bladder.
Description
TECHNICAL FIELD
[0001] The present invention relates to methods and apparatuses for
planarizing microelectronic substrate assemblies. More
particularly, the present invention relates to web-format
planarizing machines that stretch a medial region of the polishing
pad more than side regions to compensate for uneven wrapping of a
used portion of the polishing pad around a take-up roller.
BACKGROUND OF THE INVENTION
[0002] Mechanical and chemical-mechanical planarizing processes
(collectively "CMP") are used in the manufacturing of electronic
devices for forming a flat surface on semiconductor wafers, field
emission displays and many other microelectronic substrate
assemblies. CMP processes generally remove material from a
substrate assembly to create a highly planar surface at a precise
elevation in the layers of material on the substrate assembly.
[0003] FIG. 1 is a schematic isometric view of a web-format
planarizing machine 10 for planarizing a microelectronic substrate
assembly 12. The planarizing machine 10 has a table 11 with a rigid
panel or plate to provide a flat, solid support surface 13 for
supporting a portion of a web-format planarizing pad 40 in a
planarizing zone "A." The planarizing machine 10 also has a pad
advancing mechanism including a plurality of rollers to guide,
position, and hold the web-format pad 40 over the support surface
13. The pad advancing mechanism generally includes a supply roller
20, first and second idler rollers 21a and 21b, first and second
guide rollers 22a and 22b, and a take-up roller 23. As explained
below, a motor (not shown) drives the take-up roller 23 to advance
the pad 40 across the support surface 13 along a travel axis T-T.
The motor can also drive the supply roller 20. The first idler
roller 21a and the first guide roller 22a press an operative
portion of the pad against the support surface 13 to hold the pad
40 stationary during operation.
[0004] The planarizing machine 10 also has a carrier assembly 30 to
translate the substrate assembly 12 across the pad 40. In one
embodiment, the carrier assembly 30 has a head 32 to pick up, hold
and release the substrate assembly 12 at appropriate stages of the
planarizing process. The carrier assembly 30 also has a support
gantry 34 and a drive assembly 35 that can move along the gantry
34. The drive assembly 35 has an actuator 36, a drive shaft 37
coupled to the actuator 36, and an arm 38 projecting from the drive
shaft 37. The arm 38 carries the head 32 via another shaft 39. The
actuator 36 orbits the head 32 about an axis B-B to move the
substrate assembly 12 across the pad 40.
[0005] The polishing pad 40 may be a non-abrasive polymeric pad
(e.g., polyurethane), or it may be a fixed-abrasive polishing pad
in which abrasive particles are fixedly dispersed in a resin or
another type of suspension medium. A planarizing fluid 50 flows
from a plurality of nozzles 49 during planarization of the
substrate assembly 12. The planarizing fluid 50 may be a
conventional CMP slurry with abrasive particles and chemicals that
etch and/or oxidize the surface of the substrate assembly 12, or
the planarizing fluid 50 may be a "clean" non-abrasive planarizing
solution without abrasive particles. In most CMP applications,
abrasive slurries with abrasive particles are used on non-abrasive
polishing pads, and non-abrasive clean solutions without abrasive
particles are used on fixed-abrasive polishing pads.
[0006] In the operation of the planarizing machine 10, the pad 40
moves across the support surface 13 along the pad travel path T-T
either during or between planarizing cycles to change the
particular portion of the polishing pad 40 in the planarizing zone
A. For example, the supply and take-up rollers 20 and 23 can drive
the polishing pad 40 between planarizing cycles such that a point P
moves incrementally across the support surface 13 to a number of
intermediate locations I.sub.1, 1.sub.2, etc. Alternatively, the
rollers 20 and 23 may drive the polishing pad 40 between
planarizing cycles such that the point P moves all the way across
the support surface 13 to completely remove a used portion of the
pad 40 from the planarizing zone A. The rollers may also
continuously drive the polishing pad 40 at a slow rate during a
planarizing cycle such that the point P moves continuously across
the support surface 13. Thus, the polishing pad 40 should be free
to move axially over the length of the support surface 13 along the
pad travel path T-T.
[0007] CMP processes should consistently and accurately produce a
uniform, planar surface on substrate assemblies to enable circuit
and device patterns to be formed with photolithography techniques.
As the density of integrated circuits increases, it is often
necessary to accurately focus the critical dimensions of the
photo-patterns to within a tolerance of approximately 0.1-0.2
.mu.m. Focusing photo-patterns to such small tolerances, however,
is difficult when the planarized surfaces of substrate assemblies
are not uniformly planar. Thus, to be effective, CMP processes
should create highly uniform, planar surfaces on substrate
assemblies.
[0008] Although web-format planarizing machines show promising
results, the polishing pad 40 may develop wrinkles in the
planarizing zone A as more of the used portion of the pad wraps
around the take-up roller 23. More specifically, the middle region
of the polishing pad 40 wears more than the side regions because
the substrate assembly 12 does not contact the side regions during
planarization. The middle region of the used portion of the
polishing pad 40 is accordingly thinner than the side regions, and
the middle region of the portion of the pad 40 wrapped around the
take-up roller 23 accordingly has a smaller diameter than the side
regions. The torque applied to the take-up roller 23 thus exerts a
non-uniform tension across the width of the pad 40 that causes the
polishing pad 40 to wrinkle or slip during a planarizing cycle.
Additionally, as the polishing pad is transferred from the supply
roller 20 to the take-up roller 23, the torque applied to the
take-up roller 23 must be continually adjusted to mitigate wrinkles
and slippage in the middle portion of the polishing pad 40.
SUMMARY OF THE INVENTION
[0009] The present invention is directed toward methods and
machines for planarizing microelectronic substrate assemblies in
mechanical and/or chemical-mechanical planarizing processes. For
the purposes of the present application, the term "planarizing"
means both planarizing substrate assemblies to form a planar
surface and polishing substrate assemblies to form a smooth
surface.
[0010] One machine in accordance with an embodiment of the
invention includes a table having a support surface with a
planarizing zone, an elongated polishing pad configured to move
across the support surface of the table along a pad travel path,
and a pad advancing mechanism coupled to the pad. The elongated pad
can have a length along an elongated dimension extending along the
pad travel path. The length of the polishing pad, for example, is
generally sufficient to extend across the table. The polishing pad
further includes an elongated first edge, an elongated second edge
opposite the first edge, an elongated first side region extending
along the first edge, an elongated second side region extending
along the second edge, and an elongated medial region having a
width between the first and second side regions. The pad advancing
mechanism can include a first roller about which an unused portion
of the pad is wrapped and a second roller about which a used
portion of the pad is wrapped. At least one of the first and second
rollers is driven to advance the pad across the table along the pad
travel path for positioning a desired active section of the pad in
the planarizing zone.
[0011] The planarizing machine can further include a carrier
assembly having a head and a drive system. The head is configured
to hold a microelectronic substrate assembly, and the drive system
moves the head to translate the substrate assembly across the
active section of the polishing pad in the planarizing zone. In
several embodiments of the invention, for example, a planarizing
solution is deposited onto the polishing pad and the carrier
assembly translates the substrate assembly across the active
section of the polishing pad to remove material from the substrate
assembly. The planarizing solution and/or the polishing pad can
accordingly include abrasive particles to abrade the surface of the
substrate assembly.
[0012] The planarizing machine further includes a pad tensioning
system between the planarizing zone of the table and at least one
of the first and second rollers. The tensioning system, for
example, can have a pneumatic or mechanical stretching assembly
configured to push or pull the medial region of the pad more than
the first and second side regions to compensate for the smaller
diameter of the used portion of the pad wrapped around the second
roller. The pad tensioning system, for example, can include an
engagement member aligned with the medial region of the pad and an
actuator connected to the engagement member. The engagement member
generally extends transverse to the elongated dimension of the pad
and has a length less than the width of the pad between the first
and second edges. The actuator moves the engagement member to press
the engagement member against the medial region of the pad so that
the engagement member stretches the medial region of the pad more
than the first and second side regions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic isometric view of a web-format
planarizing machine in accordance with the prior art.
[0014] FIG. 2 is a schematic isometric view of a web-format
planarizing machine for mechanical and/or chemical-mechanical
planarization of microelectronic substrate assemblies in accordance
with an embodiment of the invention.
[0015] FIG. 3A is a cross-sectional side view schematically
illustrating a tensioning system for a planarizing machine in
accordance with an embodiment of the invention.
[0016] FIG. 3B is a cross-sectional top view of the tensioning
system of FIG. 3A.
[0017] FIG. 4A is a cross-sectional side view schematically
illustrating a tensioning system for a planarizing machine in
accordance with another embodiment of the invention.
[0018] FIG. 4B is a cut-away end view of the tensioning system of
FIG. 4A.
[0019] FIG. 5A is a cross-sectional side view of a tensioning
system for a planarizing machine in accordance with another
embodiment of the invention.
[0020] FIG. 5B is a cross-sectional top view of the tensioning
system of FIG. 5A.
[0021] FIG. 6A is a cross-sectional side view of a tensioning
system for a planarizing machine in accordance with another
embodiment of the invention.
[0022] FIG. 6B is a cut-away end view of the tensioning system of
FIG. 6A.
[0023] FIG. 7A is a cross-sectional side view of a tensioning
system for a planarizing machine in accordance with yet another
embodiment of the invention.
[0024] FIG. 7B is a cut-away end view of the tensioning system of
FIG. 7A.
[0025] FIG. 8A is a cross-sectional side view of a tensioning
system for a planarizing machine in accordance with another
embodiment of the invention.
[0026] FIG. 8B is a cross-sectional top view of the tensioning
system of FIG. 8A.
[0027] FIG. 9 is a cross-sectional top view of a tensioning system
for a planarizing machine in accordance with another embodiment of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The present invention relates to holding a web-format
polishing pad on a planarizing machine in mechanical and/or
chemical-mechanical planarization of semiconductor wafers, field
emission displays and other microelectronic substrate assemblies.
Many specific details of the invention are described below with
reference to FIGS. 2-9 to provide a thorough understanding of
several embodiments of the present invention. The invention,
however, may have additional embodiments or can be practiced
without several of the details described in the following
embodiments.
[0029] FIG. 2 is a schematic isometric view of a web-format
planarizing machine 100 for planarizing a microelectronic substrate
assembly 12 in accordance with an embodiment of the invention. The
planarizing machine 100 includes a table 110, a carrier assembly
130 over the table 110, and a polishing pad 140 on the table 110.
The carrier assembly 130 and the polishing pad 140 can be
substantially the same as those described above with reference to
FIG. 1. The polishing pad 140 has an elongated first edge 143, an
elongated second edge 144 opposite the first edge 143, an elongated
first side region 145 extending along the first edge 143, an
elongated second side region 146 extending along the second edge
144, and a medial region 147 between the first and second side
regions 145 and 146. The polishing pad 140 is also coupled to a
pad-advancing mechanism having a supply roller 120, a plurality of
guide rollers 122a-c, and a take-up roller 123. The pad advancing
mechanism shown in FIG. 2 can operate similar to the pad advancing
mechanism described above with reference to FIG. 1.
[0030] The planarizing machine 100 also includes a pad tensioning
system 160 (shown schematically in FIG. 2) at a tensioning site 114
on the table 110. The tensioning system 160 is generally positioned
at a used portion of the polishing pad 140 between the planarizing
zone A of the table 110 and the take-up roller 123 (shown in solid
lines in FIG. 2), but the tensioning system 160 can be located at
an unused portion of the polishing pad 140 between the planarizing
zone A and the supply roller 120 (shown in broken lines in FIG. 2).
The tensioning system 160 pulls or pushes a section of the medial
region 147 of the pad 140 to compensate for the uneven tension
exerted by the take-up roller 123 across the width of the polishing
pad 140. Several particular embodiments of tensioning systems in
accordance with the invention are explained in greater detail below
with reference to FIGS. 3-9.
[0031] FIGS. 3A and 3B are schematic cross-sectional views of an
embodiment of a tensioning system 160a for the planarizing machine
100 taken along a side cross-section A-A (FIG. 2) and a top
cross-section B-B (FIG. 2), respectively. In this embodiment,
tensioning site 114 is between the planarizing zone A (FIG. 3A) and
the second roller 123 (FIG. 3A). The tensioning site 114 can
include an elongated recess 115 under a used section of the
polishing pad 140. As best shown in FIG. 3B, the recess 115 is
aligned with the medial region 147 of the pad 140 and extends
width-wise relative to the width of the pad 140.
[0032] The tensioning system 160a includes an inflatable bladder
162a defining an engagement member and a fluid pump 164a defining
an actuator. The bladder 162a generally conforms to the recess 115,
and thus the bladder 162a is also aligned with the medial region
147 of the pad 140 and extends transversely to the edges 143/144 of
the pad 140. The bladder 162a is coupled to the pump 164a by a
fluid line 165. The fluid can be air, water or another suitable
fluid for pneumatic or hydraulic pressurization of the bladder
162a. The pump 164a inflates or deflates the bladder 162a to move a
contact surface 166a of the bladder 162a against a back side of the
polishing pad 140. The inflatable bladder 162a accordingly
stretches the medial region 147 of the pad 140 more than the side
regions 145/146 to compensate for the lower tension applied to the
medial region 147 by the take-up roller 123. It will be appreciated
that the extent of deformation in the medial region 147 shown in
FIGS. 3A and 3B is exaggerated greatly for illustrative
purposes.
[0033] The tensioning system 160a can be continually adjusted to
reduce or eliminate wrinkles in the medial region 147 of the pad
140. Referring to FIGS. 2-3B together, the pad advancing mechanism
and the tensioning system 160a operate by releasing the supply
roller 120 and driving the take-up roller 123 to move the pad 140
across the table 110. When a desired active portion of the pad 140
is in the planarizing zone A, a brake assembly (not shown) prevents
the supply roller 120 from rotating further and a drive motor (not
shown) applies a torque to the take-up roller 123. The torque
applied by the drive motor is adjusted so that the take-up roller
123 exerts the desired tension on the side regions 145/146 of the
pad 140. The tensioning system 160a is also activated to adjust the
pressure of the fluid in the inflatable bladder 162a. The pressure
in the inflatable bladder 162a is set to stretch the medial region
147 of the pad 140 according to the difference in diameter between
the medial region 147 and the side regions 145/146 of the pad 140
wrapped around the take-up roller 123. For example, as more of the
used portion of the pad 140 wraps around the take-up roller 123,
the difference in tension increases between the side regions
145/146 and the medial region 147. The pump 164a accordingly
increases the pressure in the inflatable bladder 162a as more of
the used portion of the pad 140 wraps around the take-up roller 123
to increase the tension in the medial region 147. Therefore, the
tensioning system 160a is expected to reduce or eliminate wrinkles
in the medial region 147 of the pad 140 caused by the difference in
wear between the medial region 147 and the side regions
145/146.
[0034] FIG. 4A is a cross-sectional side view and FIG. 4B is a
partial cut-away view of a tensioning system 160b for the
planarizing machine 100 in accordance with another embodiment of
the invention. The tensioning system 160b includes a diaphragm 162b
defining an engagement member and a fluid pump 164b defining an
actuator. The diaphragm 162b is at the tensioning site 114 of the
table 110. A fluid line 165 couples the fluid pump 164b to an
orifice 116 at the tensioning site 114 in the table 110 behind the
diaphragm 162b. The perimeter of the diaphragm 162b is attached to
the table 110 by a clamp ring 117 and a number of fasteners 118
(e.g., screws or bolts). The diaphragm 162b and the clamp ring 117
are aligned with the medial region 147 of the pad 140 and extend
transversely to the edges 143/144 of the pad 140.
[0035] The tensioning system 160b operates in a manner similar to
that describe above with respect to the tensioning system 160a of
FIGS. 3A and 3B. The fluid pump 164b, for example, inflates or
deflates the diaphragm 162b and the table 110 to move the diaphragm
162b against the back side of the pad 140. Because the diaphragm
162b is aligned with the medial region 147 of the pad 140 and does
not extend into the side regions 145/146, the tensioning system
160b stretches the medial region 147 more than the side regions
145/146 to compensate for the slack in the medial region 147 of the
pad 140.
[0036] FIG. 5A is a cross-sectional side view and FIG. 5B is a
cross-sectional top view of a tensioning system 160c for the
planarizing machine 110 in accordance with yet another embodiment
of the invention. The tensioning system 160c is a pneumatic
stretching assembly having a fluid pump 164c and a fluid line 165
coupling the fluid pump 164c to an orifice 116 in the table 110.
The orifice 116 is positioned in an elongated recess 115 at the
tensioning site 114 of the table 110. The elongated recess extends
transversely to the edges 143/144 in alignment with the medial
region 147 of the pad 140. In operation, the fluid pump 164c draws
a negative pressure in the elongated recess 115 to pull a section
of the medial region 147 into the recess 115. The tensioning system
160c accordingly stretches the medial region 147 of the pad 140
more than the side regions 145/146. The negative pressure produced
by the fluid pump 164c can be adjusted to compensate for the extent
that the diameter of the used portion of the polishing pad 140
wrapped around the take-up roller 123 varies as the pad 140 wraps
around the take-up roller 123.
[0037] FIG. 6A is a cross-sectional side view and FIG. 6B is a
cut-away end view of a tensioning system 160d for the planarizing
machine 100 in accordance with another embodiment of the invention.
The tensioning system 160d includes an inflatable toroidal bladder
162d defining an engagement member mounted to a rotating spindle
163d. The bladder 162d and the spindle 163d are aligned with the
medial region 147 and extend transversely to the edges 143/144 of
the pad 140 in an elongated cavity 115 at the tensioning site 114
on the table 110. Each end of the spindle 163d is rotatably
attached to a support leg 167d projecting from the table 110 into
the recess 115. The tensioning system 160d also includes a fluid
pump 164d defining an actuator coupled to the toroidal bladder 162d
by fluid lines 165d and 169d. The fluid lines 165d and 169d are
rotatably coupled by a rotating fluid joint 168d so that the
toroidal bladder 162d and the spindle 163d can rotate (arrow R) as
the polishing pad 140 wraps around the take-up roller 123. Suitable
rotating fluid joints 168d are known in the mechanical arts. In
operation, the fluid pump 164d inflates or deflates the toroidal
bladder 162d to adjust the pressure that the toroidal bladder 162d
exerts against the back side of the pad 140. Accordingly, the
tensioning system 160d is expected to perform in substantially the
same manner as the tensioning systems 160a-160c described
above.
[0038] The tensioning system 160d shown in FIGS. 6A and 6B can also
have components that limit the expansion of the toroidal bladder
162d, or the toroidal bladder 162d can have several different
partitions or segments to vary the expansion of the bladder 162d
along the roller 163d. Referring to FIG. 6A, for example, the
toroidal bladder 162d can include a number of internal tethers 170d
or the table 110 can have a number of idler rollers 172d in the
recess 115. The tethers 170d and the idler rollers 172d limit
expansion of the toroidal bladder 162d to prevent it from
ballooning in the recess 115 as it expands against the polishing
pad 140. Referring to FIG. 6B, the toroidal bladder 162d can also
have a plurality of partitions 173d that are separately controlled
by individual fluid lines 174d. The individual fluid lines 174d,
for example, can be separately controlled by remotely operated
valves 175d to vary the fluid pressure in the partitions 173d so
that the contour of the toroidal bladder 162d can be varied along
the length of the roller 163d.
[0039] FIG. 7A is a cross-sectional side view and FIG. 7B is a
cutaway end view of a tensioning system 160e for the planarizing
machine 100 in accordance with yet another embodiment of the
invention. The tensioning system 160e includes a rotating
engagement member 162e attached to a spindle 163e. The engagement
member 162e can be a tubular member made from compressible
materials (e.g., foam or soft rubbers) or substantially
incompressible materials (e.g., high-density polymers, metals,
etc.). The tensioning system 160e also includes first and second
linear actuators 164e having rods 165e attached to opposing ends of
the spindle 163e. The linear actuators 164e and the engagement
member 162e can be positioned in an elongated recess 115 at the
tensioning site 114. The linear actuators 164e drive the rods 165e
to adjust the force exerted by the engagement member 162e against
the back side of the medial region 147 of the pad 140. For example,
the linear actuators 164e generally increase the extension of the
rods 165e as the used portion of the polishing pad 140 wraps around
the take-up roller 123 to compensate for the increase in the
difference in the diameter between the side regions 145/146 and the
medial region 147 across the take-up roller 123.
[0040] FIG. 8A is a cross-sectional side view and FIG. 8B is a
cross-sectional top view of another tensioning system 160f for the
planarizing machine 100 in accordance with an embodiment of the
invention. The tensioning system 160f includes a push-plate 162f
defining an engagement member. The push-plate 162f in the
embodiment shown in FIGS. 8A and 8B has a compressible contact
member 166f contacting the back side of the polishing pad 140 and a
rigid back-plate 167f attached to the contact member 166f. The
compressible contact member 166f, for example, can be a foam or
rubber pad that deforms more at the side of the medial region 147
than at the center in reaction to the increasing tension in the pad
140 toward the edges 143/144. The tensioning system 160f also
includes a linear actuator 164f having a rod 165f attached to the
back-plate 167f. The push-plate 162f and the actuator 164f are
positioned in an elongated recess 115 at the tensioning site 114 on
the table 110. The linear actuator 164f extends the rod 165f to
push the contact member 166f against the back side of the medial
region 147 of the polishing pad 140. The tensioning system 160f can
operate in much the same manner as the tensioning system 160e
described above with reference to FIGS. 7A and 7B.
[0041] FIG. 9 is a cross-sectional top view of a tensioning system
160g having a push-plate 162g attached to a linear actuator 164g in
an elongated recess 115 at the tensioning site 114. In this
embodiment, the push-plate 162g can be a curved plate or a flexible
plate that has an apex at approximately a midpoint of the medial
region 147 of the pad 140. The curvature of the push-plate 162g can
be shaped to be proportionate to the tension distribution across
the, medial region 147 of the pad 140. The linear actuator 164g
extends or retracts a rod 165g to drive the push-plate 162g against
the back side of the medial region 147 of the polishing pad.
[0042] From the foregoing it will be appreciated that, although
specific embodiments of the invention have been described herein
for purposes of illustration, various modifications may be made
without deviating from the spirit and scope of the invention. For
example, the engagement member and actuator can be other structures
that push or pull the medial region 147 of the pad 140 more than
the side regions 145/146. The bladders, diaphragms, rollers and
push-plates can also have different shapes than those shown in
FIGS. 3-9. The push-plates shown in FIGS. 8A-9, for example, can
also have ball bearings at the contact surface to allow the pad 140
to slide over the push-plates as the pad moves incrementally along
the pad travel path. The embodiments of the invention shown and
described above with reference to FIGS. 2-9 are thus merely the
best known examples of the invention for providing a more uniform
tension across the width of a web-format pad to inhibit the pad
from wrinkling or slipping in the planarizing zone. Accordingly,
the invention is not limited except as by the appended claims.
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