|Publication number||US3453783 A|
|Publication date||Jul 8, 1969|
|Filing date||Jun 30, 1966|
|Priority date||Jun 30, 1966|
|Publication number||US 3453783 A, US 3453783A, US-A-3453783, US3453783 A, US3453783A|
|Inventors||William D Queen|
|Original Assignee||Texas Instruments Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (9), Referenced by (44), Classifications (11)|
|External Links: USPTO, USPTO Assignment, Espacenet|
July 8, 1969 w. D. QUEEN 3,453,783
APPARATUS FOR HOLDING SILICON SLICES Filed June 50, 1966 INVENTORZ l LIAM D. U FIG. 3 WL O EEN ATTORNEY United States Patent 3,453,783 APPARATUS FOR HOLDING SILICON SLICES William D. Queens, Dallas, Tex., assignor to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Filed June 30, 1966, Ser. No. 561,943 Int. Cl. B24b 41/06, /00, 29/00 US. Cl. 51-216 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for holding thin wafers for polishing, and more particularly, but not by way of limitation, to apparatus for holding silicon slices for polishing.
In the manufacture of electronic devices from silicon, it is common to form relatively thin silicon slices which must be polished on at least one face.
A conventional manner of mounting the slices involves affixing the slices to a polishing block by use of cerese wax or beeswax. The metal polishing block on which the slices are to be mounted is first heated by placing the block on a hot plate or the like. When hot, the block is rubber with a solid stick of the wax which melts to form a layer of molten wax. The wafers are dropped onto the molten wax and the block removed from the hot plate to permit the wax to solidify. To assure that the slices are level on the polishing block, a weight is placed on the slices during solidification of the wax. Any wax contacting the top, or exposed face of the slice must be removed with a suitable solvent, such as trichloroethylene. The polishing block may then be inverted and the exposed face of the wafer contacted with a rotating grinder or polisher, or alternatively the slices are rotated and contacted with a stationary grinder or polisher.
Since the slices are relatively thin, in some cases having a thickness of about mils, the wax used to affix them to the polishing block must be very clean since any particles lodging beneath the slice could cause a crack to form during application of the weight or during the grinding and polishing operations destroying the electrical properties of the silicon.
When polishing of the slices has been completed, the polishing block is again placed on a hot plate or the like to remelt the wax to permit removal of the slices. The slices, upon removal and before treatment with doping agents and the like, must be cleaned with a suitable solvent such as trichloroethylene to remove any wax adhering to the slice.
The steps of mounting and demounting the slices are time consuming, manual operations which are quite costly.
The present invention involves apparatus which greatly reduces the time necessary to mount and demount slices which are to be ground and polished. The invention may be generally described as apparatus for holding thin slices so that one face of the slice is exposed for polishing which includes means defining an opening having a configuration within which the slice may be relatively snugly accommodated. An elastomeric member forms with the opening a recess having a depth less than the thickness of the slice, and the elastomeric element is supported in this relationship by suitable means.
To be more specific, reference is here made to the drawings, in which:
FIGURE 1 is a top plan view of one embodiment of the invention;
FIGURE 2 is a cross-sectional view along line 2-2 of FIGURE 1;
FIGURES 3 is an enlarged cross-sectional view of a portion of the embodiment illustrated in FIGURES 1 and 2; and
FIGURE 4 is a partial top plan view of an alternative embodiment.
With reference to FIGURES l, 2, and 3 a conventional polishing block 4 formed of a cylindrical plate of metal or the like is provided about its periphery with a plurality of teeth 5 adapted to engage a gear, not illustrated, for driving the block. Affixed to the surface of block 4 by an adhesive 6, such as Pliobond brand adhesive, is an elastomeric member which takes the form of rubber pad 7. Rubber pad 7 preferably has a durometer of about 60 and may conveniently be between and inch thick. Affixed to the relatively planar elastomeric surface 10 of pad 7 by an adhesive 8, such as Pliobond brand adhesive, are a plurality of opening defining members, such as annular rings 9. Rings 9 are preferably made of a relatively deformable plastic material such as Mylar film which preferably have a thickness on the order of about 7.5 mils. While a Mylar film is preferred, other relatively deformable plastics and rubbers may be used.
Rings 9 form with pad 7 a plurality of recesses 11 which are adapted to receive, and accommodate relatively snugly, a plurality of silicon slices 12. The depth of recesses 11 is less than that of the thickness of the slices 12 so that faces 13 of the slices are exposed above the rings 9 to prevent contact between a grinding or polishing wheel and rings 9.
Slices 12 may be retained within recesses 11 to permit inversion of the polishing block 4 in the conventional manner by placing a drop of water on the bottom face 14 of the slice. The surface tension of the water will serve to retain the relatively light slices within recesses 11.
With particular reference to FIGURE 3, it will be noted that faces 13 and 14 of the slices 12 are rough before polishing. Pad 7, due to its elastomeric nature, will conform to the irregularities in face 14 preventing the creation of unwanted stresses in slice 12 during polishing. Additionally since the rings 9 are of a relatively deformable plastic, any engagement of the periphery 15 of the slices with rings 9 during polishing will not result in chipping of the perihpery 15 of slice 12.
While the particular embodiment illustrated in FIG- URES 1-3 is the preferred one, it is also contemplated that a plurality of recesses may be drilled in polishing block 4 and an elastomeric member placed in the bottom of the recess to abs-orb the irregularities in faces 14 of slices 12. Preferably, the peripheries of the recesses would be lined with a relatively deformable material to protect the peripheries 15 of the slices during the polishing.
It is also contemplated that rings 9 may be formed of a ferromagnetic metal in which case block 4 could be magnetized and the rings 9 adhered directly to the surface of block 4 by magnetic attraction. An elastomeric pad could then be placed in the bottom of rings 9 and adhered in place by any suitable adhesive.
In the embodiment illustrated in FIGURE 4, the need for the adhesive used in the embodiment shown in FIG- URES 1-3 is eliminated. In FIGURE 4, the polishing block 16 is covered with an elastomeric' pad 17 which in turn is covered by a circular Mylar film 18 having a plurality of apertures 19 which, with pad 17, define recesses 20 adapted to receive silicon slices 12. The elastomeric pad 17 and Mylar film 18 are retained in juxtaposition by a plurality of nuts 21 which are threadably received about a plurality of screws 22 extending through block 16, pad 17 and film 18.
Once the slices 12 illustrated in FIGURES 13 have been polished, they may be removed by flowing water into recesses 11 to float the slices from the recesses 11. The slices 12 illustrated in FIGURE 4 are removed in the same manner.
Because the slices are preferably retained in recesses 11 by use of Water and are demounted by use of Water, the adhesive used in the embodiment illustrated in FIG- URES l-3 is preferably one which will withstand repeated application of Water without deterioration.
While rather specific terms have been used in describing embodiments of the invention, they are not intended nor should they be construed as a limitation on the invention as defined by the claims.
What is claimed is:
1. An apparatus for holding a plurality of thin wafers so that one face of each Wafer is exposed for polishing, comprising:
a block having a planar surface,
an elastomeric sheet affixed to said surface,
and a plurality of annular rings afiixed to said elastomeric sheet within which said wafers may be relatively snugly accommodated,
.4 said rings being of height less than the thickness of said Wafers. 2. The apparatus of claim 1, wherein said annular rings are of a relatively deformable plastic material.
3. The apparatus of claim 1, wherein said annular rings comprise a magnetized ferromagnetic material.
References Cited UNITED STATES PATENTS 1,673,903 6/1928 Cripe 51 216 XR 1,911,221 5/1933 Blair 51-216 2,112,636 3/1938 Sawyer. 2,309,080 1/1'943 Hunt 51-283 x 2,395,700 2/1946 Walker 51 216 2,539,561 1/1951 Wolfskill 51 133 2,632,288 3/1953 Diller 51 237 X 2,736,993 3/1956 Tripp 51 131 2,699,633 1/1955 Lapenas 51 216 HAROLD D. WHITEHEAD, Primary Examiner.
US. Cl. X.R. 51--13l, 237
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1673903 *||Jun 15, 1925||Jun 19, 1928||Libbeyowens Sheet Glass Compan||Grinding and polishing table|
|US1911221 *||May 6, 1926||May 30, 1933||Libbey Owens Ford Glass Co||Glass surfacing apparatus|
|US2112636 *||Sep 2, 1936||Mar 29, 1938||Brush Dev Co||Method of making piezoelectric units|
|US2309080 *||Dec 6, 1941||Jan 19, 1943||Grover C Hunt||Work holder for grinding machines|
|US2395700 *||Mar 23, 1943||Feb 26, 1946||Alncin Inc||Method and apparatus for shaping optical objects and the like|
|US2539561 *||Dec 13, 1946||Jan 30, 1951||John M Wolfskill||Piezoelectric crystal lapping apparatus|
|US2632288 *||Feb 2, 1951||Mar 24, 1953||Diller Alfred I||Lens grinding and polishing machine|
|US2699633 *||Feb 9, 1949||Jan 18, 1955||Optron Lab||Precision supporting of articles|
|US2736993 *||Mar 25, 1953||Mar 6, 1956||American Optical Corp||Abrading apparatus|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3593462 *||Mar 24, 1969||Jul 20, 1971||Western Electric Co||Apparatus for abrading articles|
|US3699722 *||Nov 23, 1970||Oct 24, 1972||Radiation Inc||Precision polishing of semiconductor crystal wafers|
|US4132037 *||Feb 28, 1977||Jan 2, 1979||Siltec Corporation||Apparatus for polishing semiconductor wafers|
|US4193226 *||Aug 30, 1978||Mar 18, 1980||Kayex Corporation||Polishing apparatus|
|US4239567 *||Oct 16, 1978||Dec 16, 1980||Western Electric Company, Inc.||Removably holding planar articles for polishing operations|
|US4332636 *||Apr 14, 1980||Jun 1, 1982||Ferranti Limited||Method of bonding an optical element to a support|
|US4397208 *||Oct 17, 1979||Aug 9, 1983||Stalhut B R||Jewelry tag marking method|
|US4512113 *||Sep 23, 1982||Apr 23, 1985||Budinger William D||Workpiece holder for polishing operation|
|US4519168 *||Dec 5, 1983||May 28, 1985||Speedfam Corporation||Liquid waxless fixturing of microsize wafers|
|US4530139 *||Sep 23, 1983||Jul 23, 1985||At&T Bell Laboratories||Method of contouring crystal plates|
|US4689001 *||Apr 23, 1985||Aug 25, 1987||Plasti-Bat, Inc.||Bat for potters wheel|
|US5365700 *||Dec 13, 1993||Nov 22, 1994||Fujitsu Limited||Apparatus and method for producing magnetic head sliders|
|US5398459 *||Nov 24, 1993||Mar 21, 1995||Kabushiki Kaisha Toshiba||Method and apparatus for polishing a workpiece|
|US5533924 *||Sep 1, 1994||Jul 9, 1996||Micron Technology, Inc.||Polishing apparatus, a polishing wafer carrier apparatus, a replacable component for a particular polishing apparatus and a process of polishing wafers|
|US5664988 *||Feb 23, 1996||Sep 9, 1997||Micron Technology, Inc.||Process of polishing a semiconductor wafer having an orientation edge discontinuity shape|
|US6152807 *||Jul 7, 1998||Nov 28, 2000||International Business Machines Corporation||Lapping and polishing fixture having flexible sides|
|US6419555 *||Jun 1, 2000||Jul 16, 2002||Brian D. Goers||Process and apparatus for polishing a workpiece|
|US6442825||Dec 10, 1999||Sep 3, 2002||International Business Machines Corporation||Lapping and polishing fixture having flexible sides|
|US7316605||Jul 3, 2006||Jan 8, 2008||San Fang Chemical Industry Co., Ltd.||Sheet for mounting polishing workpiece and method for making the same|
|US7629554||Mar 19, 2007||Dec 8, 2009||San Fang Chemical Industry Co., Ltd.||Sheet for mounting polishing workpiece and method for making the same|
|US7789738 *||Sep 7, 2010||San Fang Chemical Industry Co., Ltd.||Sheet for mounting polishing workpiece and method for making the same|
|US7967665||Mar 29, 2007||Jun 28, 2011||Ebara Corporation||Substrate holding apparatus, polishing apparatus, and polishing method|
|US8100739||Jan 24, 2012||Ebara Corporation||Substrate holding apparatus, polishing apparatus, and polishing method|
|US8137157||Nov 19, 2007||Mar 20, 2012||3M Innovative Properties Company||Lapping carrier and method|
|US8267746||Aug 19, 2008||Sep 18, 2012||Ebara Corporation||Substrate holding apparatus, polishing apparatus, and polishing method|
|US8485866||Aug 16, 2012||Jul 16, 2013||Ebara Corporation||Substrate holding apparatus, polishing apparatus, and polishing method|
|US8579678 *||May 9, 2011||Nov 12, 2013||Disco Corporation||Grinding method for workpiece having a plurality of bumps|
|US8795033||Feb 7, 2012||Aug 5, 2014||3M Innovative Properties Company||Lapping carrier and method|
|US20070232193 *||Mar 29, 2007||Oct 4, 2007||Hozumi Yasuda||Substrate holding apparatus, polishing apparatus, and polishing method|
|US20080003932 *||Jul 3, 2006||Jan 3, 2008||Chung-Chih Feng||Sheet for mounting polishing workpiece and method for making the same|
|US20080003934 *||Mar 19, 2007||Jan 3, 2008||Chung-Chih Feng||Sheet for mounting polishing workpiece and method for making the same|
|US20080064310 *||Sep 8, 2006||Mar 13, 2008||Chung-Chih Feng||Polishing pad having hollow fibers and the method for making the same|
|US20080318492 *||Aug 19, 2008||Dec 25, 2008||Hozumi Yasuda||Substrate holding apparatus, polishing apparatus, and polishing method|
|US20080318499 *||Aug 19, 2008||Dec 25, 2008||Hozumi Yasuda||Substrate holding apparatus, polishing apparatus, and polishing method|
|US20090252876 *||Jun 10, 2009||Oct 8, 2009||San Fang Chemical Industry Co., Ltd.||Sheet for mounting polishing workpiece and method for making the same|
|US20100048105 *||Nov 19, 2007||Feb 25, 2010||3M Innovative Properties Company||Lapping Carrier and Method|
|US20110281504 *||Nov 17, 2011||Disco Corporation||Grinding method for workpiece having a plurality of bumps|
|US20130267155 *||Apr 9, 2012||Oct 10, 2013||Phuong Van Nguyen||Wafer Polishing Pad Holder Template|
|CN102581737A *||Mar 27, 2012||Jul 18, 2012||赫得纳米科技(昆山)有限公司||Modified structure of polishing epoxy plate|
|CN102581737B *||Mar 27, 2012||Mar 18, 2015||赫得纳米科技(昆山)有限公司||Modified structure of polishing epoxy plate|
|DE3319327A1 *||May 27, 1983||Dec 1, 1983||Gen Signal Corp||Work support device for thin disc-like workpieces|
|EP0185767A1 *||May 23, 1985||Jul 2, 1986||MITSUI TOATSU CHEMICALS, Inc.||Film for machining wafers|
|EP0517594A1 *||Jun 4, 1992||Dec 9, 1992||Commissariat A L'energie Atomique||Polishing machine with a tensioned finishing belt and an improved work supporting head|
|EP1839812A2 *||Mar 30, 2007||Oct 3, 2007||Ebara Corporation||Substrate holding apparatus, polishing apparatus, and polishing method|
|U.S. Classification||451/390, 451/286, 451/398, 451/411, 257/E21.214|
|International Classification||H01L21/302, B24B37/04|
|Cooperative Classification||H01L21/02024, B24B37/30|
|European Classification||B24B37/30, H01L21/02D2M2P|