U.S. patent application number 11/175855 was filed with the patent office on 2007-01-11 for carrier employing snap-fitted membrane retainer.
This patent application is currently assigned to Agere Systems, Inc.. Invention is credited to Andres B. Garcia, Frank Miceli, Jose Omar Rodriguez, Margareth Seputro, Charles A. Storey.
Application Number | 20070010180 11/175855 |
Document ID | / |
Family ID | 37618860 |
Filed Date | 2007-01-11 |
United States Patent
Application |
20070010180 |
Kind Code |
A1 |
Garcia; Andres B. ; et
al. |
January 11, 2007 |
Carrier employing snap-fitted membrane retainer
Abstract
Disclosed herein is an improved carrier design for use in a
chemical mechanical polishing process. The carrier employs a
retainer ring that is fastened to the side of carrier, as opposed
to the front of the carrier, which alleviates undesired uneven wear
of the retainer ring surface. Specifically exemplified herein is a
carrier comprising a membrane that is secured to the carrier body
by a retainer ring that is snap-fitted to the carrier body.
Inventors: |
Garcia; Andres B.; (Ocoee,
FL) ; Miceli; Frank; (Orlando, FL) ;
Rodriguez; Jose Omar; (Orlando, FL) ; Seputro;
Margareth; (Orlando, FL) ; Storey; Charles A.;
(Orlando, FL) |
Correspondence
Address: |
HITT GAINES, PC;AGERE SYSTEMS INC.
PO BOX 832570
RICHARDSON
TX
75083
US
|
Assignee: |
Agere Systems, Inc.
|
Family ID: |
37618860 |
Appl. No.: |
11/175855 |
Filed: |
July 6, 2005 |
Current U.S.
Class: |
451/364 |
Current CPC
Class: |
B24B 37/32 20130101 |
Class at
Publication: |
451/364 |
International
Class: |
B24B 41/06 20060101
B24B041/06 |
Claims
1. A carrier for use with an integrated circuit wafer comprising: a
carrier body comprising a front surface, a back surface and a side
surface; a retainer ring comprising a first portion sized and
configured for positioning on a portion of said front surface and
having a second portion attached to or integrated with said first
portion, said second portion comprising an inner surface sized and
configured for positioning on all or a portion of said side
surface; a snap fit mechanism defined on said inner surface and
said side surface for securing said retainer ring to said carrier
body; and a membrane covering a portion of said front surface and
secured to said carrier body by said retainer ring.
2. The carrier of claim 1, wherein said snap fit mechanism
comprises a raised structure defined on said inner surface and a
receptacle defined on said side surface into which said raised
structure fits.
3. The carrier of claim 1, wherein said snap fit mechanism
comprises a raised structure defined on said side surface and a
receptacle defined on said inner surface into which said raised
structure fits.
4. The carrier of claim 1, wherein said retainer ring and said
carrier body comprise an annular dimension.
5. The carrier of claim 1, wherein said retainer ring is secured to
said carrier body without the need for employing screws or an
adhesive.
6. The carrier of claim 1, wherein a cross-section of said retainer
ring depicts an L-shaped structure.
7. The carrier of claim 1, wherein said first portion comprises an
axis that is transverse to an axis of said second portion.
8. The carrier of claim 7, wherein said first portion is
perpendicular to said second portion.
9. The carrier of claim 1, wherein said front surface and said back
surface is circular and wherein said retainer ring is
ring-shaped.
10. The carrier of claim 1, wherein said carrier body comprises a
portal to deliver and remove air from a space defined between said
membrane and said front surface.
11. The carrier of claim 1, wherein said membrane comprises an
outer edge onto which said front portion applies force to secure
said membrane to said carrier body.
12. A carrier for use with an integrated circuit wafer comprising:
a carrier body comprising a front surface, a back surface and a
side surface; a retainer ring comprising a first portion sized and
configured for positioning on a portion of said front surface and
having a second portion attached to or integrated with said first
portion, said second portion comprising an inner surface sized and
configured for positioning on all or a portion of said side
surface, wherein said second portion is engaged to said side
surface; and a membrane covering a portion of said front surface
and secured to said carrier body by said retainer ring.
Description
[0001] Conventional chemical/mechanical polishing (CMP) has been
developed for providing smooth topographies of the various layers
formed during semiconductor device manufacture. The CMP process
involves holding, and rotating, a thin, reasonably flat,
semiconductor wafer against a rotating polishing platen. The wafer
may be repositioned radially within a set range on the polishing
platen as the platen is rotated. The polishing surface, which is
conventionally an open-celled, polyurethane pad affixed to the
polishing platen, is wetted by a chemical slurry, under controlled
chemical, pressure, and temperature conditions. The chemical slurry
contains selected chemicals which etch or oxidize selected surfaces
of the wafer during CMP in preparation for their mechanical
removal. The slurry also contains a polishing agent, such as
alumina or silica that is used as the abrasive material for the
physical removal of the etched/oxidized material. The combination
of chemical and mechanical removal of material during polishing
results in superior planarization of the polished surface. In this
process it is important to remove a sufficient amount of material
to provide a smooth surface, without removing an excessive amount
of underlying materials at each level of the manufacturing process
to insure uniform and accurate formation of the semiconductor
device at all subsequent levels. Accurate material removal is
particularly important in today's sub-quarter micron technologies
where it is critical to minimize thickness variation because the
metal lines are getting thinner.
[0002] The carrier head provides a controllable load, i.e.,
pressure, on the wafer to push it against the polishing pad. Some
carrier heads include a flexible membrane that provides a mounting
surface for the wafer, and a retaining ring to hold the membrane to
the mounting surface. Pressurization or evacuation of a chamber
behind the flexible membrane controls the load on the wafer. In
addition to securing the membrane, the retainer ring acts as a wear
surface to assist in the controlled polishing of the wafer. The
retainer ring is secured to the periphery of the carrier which
secures the edges of the membrane. Such retainer rings are
typically secured either through the use of screws or an adhesive.
The screw method and adhesive method of attaching the ring to the
carrier tends to create uneven wear. Screwing the ring down tends
to buckle the ring slightly. As for the adhesive method, it is very
difficult to apply the adhesive evenly, which causes slight raises
or dips in the ring. If the retainer ring does not seat on the
polishing pad evenly, this can cause undesired stresses on the
wafer.
SUMMARY
[0003] According to one aspect, the subject invention pertains to a
wafer carrier pad comprising a membrane secured to the carrier by a
retainer ring, wherein the retainer ring is engaged to the carrier
without screws or adhesive. Of particular interest is a retainer
ring configured such that it engages the carrier by a friction fit
or snap fit. In another embodiment, the subject invention pertains
to a retainer ring for engaging to the periphery of a carrier for
transporting and holding a wafer, said carrier having a front
surface and a back surface and a side surface disposed between said
front and back surfaces. The retainer ring comprises a first
portion sized for extending from the periphery of the carrier to a
distance toward the center of the carrier sufficient for holding a
membrane. Attached to or integrated with the first portion is a
second portion extending transverse to an axis of the first
portion. The second portion is sized to span at least a portion of
the length of the side surface of the carrier. The second portion
comprises an inner wall which abuts against the side surface, and
defined on the inner wall is a raised structure. As the retainer
ring is engaged to the carrier, the at least one raised structure
fits into at least one receptacle defined in the carrier. In a
specific aspect, the receptacle is defined in the side surface of
the carrier, including at the location where the side and back
surfaces meet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 shows a side perspective view of a carrier embodiment
comprising a membrane secured with a retainer ring snap fitted to
the carrier.
[0005] FIG. 2 shows a cross-sectional view of the embodiment shown
in FIG. 1 along the M axis.
DETAILED DESCRIPTION
[0006] Reference is made to FIGS. 1 and 2. FIG. 1 shows a
perspective side view of a carrier embodiment 100 according to the
subject invention. FIG. 2 shows a cross-section of the carrier
embodiment 100 along axis AA. The carrier 100 comprises a carrier
body 108 which serves as the primary support for the other
components of the carrier 100. A membrane 112 is disposed on a
front surface 106 of the carrier. In the embodiment shown, pressure
under the membrane 112 may be controlled by applying air or vacuum
to the chamber 114. As described above, the level of polishing of a
wafer (not shown) positioned onto the membrane 112 may be
controlled by applying pressure under the membrane 112, which
serves to push the wafer (not shown) against a polishing pad (not
shown). Air is delivered or removed through the portal 116 which is
in fluid communication with the chamber 114. As mentioned, a vacuum
may also be applied to the chamber 114. The membrane 112 may
comprise one or more small holes (not shown). When a vacuum is
applied to the chamber 114 under the membrane 112, the wafer is
held against the membrane by the vacuum applied through such holes
in accordance with conventional methods.
[0007] The membrane 112 is secured to the front surface 106 of the
carrier body 108 by employing a ring-shaped retainer ring 110
engaged to the periphery of the carrier body 108. The retainer ring
110 comprises a first portion 111 configured and sized to lay upon
the periphery of the front surface 106 such that the edge 113 of
the membrane 112 is held under the first portion 111. Attached to
or integrated with the first portion 111 is a second portion 115
configured and sized to span a portion of the side surface 117 of
the carrier body 108. The cross section of the first and second
portions 111,115 is generally L-shaped.
[0008] The second portion 115 comprises a raised structure 118
defined on its inward side 119 which is configured to fit into a
receptacle 120 defined on the side surface 117. In the embodiment
shown in FIG. 2, the receptacle is defined at the junction between
the side surface 117 and the back surface 104 of the carrier body
108. The raised structure 118 catches or snaps into the receptacle
120 to securely fasten the retainer ring 110 to the carrier body
108. It should be noted that in alternative embodiments the side
surface comprises a raised structure and the second portion
comprises a receptacle into which the raised structure fits; or the
second portion and side surface may both comprise interlocking
raised features. Those skilled in the art will appreciate that
other snap fit or friction fit mechanisms for securing the retainer
ring 110 to the carrier body 108 may be implemented. For example,
clasp configurations, tongue and groove configurations with or
without clasp configurations and many other configurations could be
adapted for securing the retainer ring to the carrier body 108 that
do not need screws or adhesives for secure engagement.
[0009] While the preferred embodiments of the present invention
have been shown and described herein in the present context, it
will be obvious that such embodiments are provided by way of
example only and not of limitation. Numerous variations, changes
and substitutions will occur to those of skilled in the art without
departing from the invention herein. For example, the present
invention need not be limited to best mode disclosed herein, since
other applications can equally benefit from the teachings of the
present invention. Accordingly, it is intended that the invention
be limited only by the spirit and scope of the appended claims.
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