Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 1 of 7 PageID #: 152
`Case 2:20-cv-00048—JRG Document 1—4 Filed 02/21/20 Page 1 of 7 PageID #: 152
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`EXHIBIT D
`EXHIBIT D
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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 2 of 7 PageID #: 153
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`(12) United States Patent
`Easter et al.
`
`USOO6281129B1
`(10) Patent No.:
`US 6,281,129 B1
`(45) Date of Patent:
`Aug. 28, 2001
`
`(54) CORROSION-RESISTANT POLISHING PAD
`CONDITIONER
`
`(75) Inventors: William G. Easter; John A. Maze;
`Sailesh M. Merchant, all of Orlando,
`FL (US)
`(73) Assignee: Agere Systems Guardian Corp.,
`Orlando, FL (US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(*) Notice:
`
`(21) Appl. No.: 09/399,621
`(22) Filed:
`Sep. 20, 1999
`
`1/1996 Adair et al. ............................ 117/90
`5,485,804
`7/1999 Zimmer ................................ 451/539
`5,921,856
`6,027,659 * 2/2000 Billett ......
`... 438/691
`6,051,495
`4/2000 Burke et al. ......................... 438/692
`
`* cited by examiner
`
`Primary Examiner Benjamin L. Utech
`Assistant Examiner Duy-Vu Deo
`(57)
`ABSTRACT
`
`The present invention provides a method of manufacturing
`a Semiconductor device using a polishing apparatus having
`polishing pad conditioning wheel. In one embodiment, the
`polishing pad conditioning wheel comprises a conditioning
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`(51) Int. C.7 - - - - - - - - - - - - - - - - - - - - - - - - HOL 21/302; HO1L 21/461
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`head, Setting alloy, an abrasive material, and a corrosion
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`(52) U.S. C. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 438/691; 438/692
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`resistant coating. The conditioning head has opposing first
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`(58) Field of Search ..................................... 438/691, 692,
`438/693; 451/56, 72, 910; 427/249.8, 249.11,
`249.12
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`(56)
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`References Cited
`
`U.S. PATENT DOCUMENTS
`5,216,843 * 6/1993 Breivogel et al. .................. 51/131.1
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`
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`and Second faces with the first face being coupleable to the
`polishing apparatus. The Setting alloy is coupled to the
`conditioning head at the Second face, and the abrasive
`material is embedded in the Setting alloy, which is Substan
`tially covered by the corrosion resistant coating.
`
`9 Claims, 2 Drawing Sheets
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`

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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 3 of 7 PageID #: 154
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`U.S. Patent
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`Aug. 28, 2001
`Sheet 1 of 2
`FIG. 1
`(PRIOR ART)
`
`US 6,281,129 B1
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`FIG. 2
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`210
`Lee ALALAAAAAAAA
`230
`220
`240
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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 4 of 7 PageID #: 155
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`U.S. Patent
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`Aug. 28, 2001
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`Sheet 2 of 2
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`US 6,281,129 B1
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`FIG. 3
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`-200
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`240
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`340
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`230
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`FIG. 4
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`470
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`460
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`400
`u1
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`%2 SS6S-66
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`440
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`430
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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 5 of 7 PageID #: 156
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`US 6,281,129 B1
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`1
`CORROSION-RESISTANT POLISHING PAD
`CONDITIONER
`
`TECHNICAL FIELD OF THE INVENTION
`The present invention is directed, in general, to a Semi
`conductor wafer polishing apparatus and, more specifically,
`to a polishing pad conditioner having improved corrosion
`resistance against the chemicals of a chemical/mechanical
`planarization process.
`
`BACKGROUND OF THE INVENTION
`Chemical mechanical planarization (CMP) is an essential
`proceSS in the manufacture of Semiconductor chips today.
`Dielectric and metal layers used in chip fabrication must be
`made extremely flat and of precise thickneSS in order to
`pattern the Sub-micron sized features that comprise a Semi
`conductor device. During CMP, the combination of chemical
`etching and mechanical abrasion produces the required flat,
`precise Surface for Subsequent depositions. The polishing
`pad is usually made of polyurethane and has Small pores to
`carry the Slurry under the wafer. As a result of the polishing
`process, pad material and Slurry residues collect in the pores,
`plugging them, and reducing the polish rate due to Slurry
`Starvation. When the pad becomes clogged, it becomes
`necessary to “condition' the pad to restore its full function
`ality. That is, the accumulated material must be removed
`before it completely clogs the pad and results in a Smooth,
`glazed Surface that does not effectively polish the Semicon
`ductor wafer. A nickel/chromium conditioning wheel with a
`Surface of diamond abrasives embedded in a nickel/
`chromium Setting alloy is used to condition the pad. The
`conditioning wheel is pressed against the polishing pad by a
`conditioning wheel actuator, e.g., a hydraulic arm, and the
`pad and conditioning wheel are rotated while de-ionized
`water is flowed to rinse away abraded material. The diamond
`elements remove embedded particles, slurry, and polishing
`by-products from the polishing pad. The conditioning pro
`ceeds until the pad is "re-Surfaced' and new pores are
`exposed.
`AS the conditioning wheel is rotated against the polishing
`pad, the wheel, Setting alloy, and the diamonds come in
`contact with the chemical/mechanical Slurry. Conventional
`conditioners for an oxide polisher have useable lifetime of
`about 15,000 wafers. On the other hand, conventional con
`ditioners for a tungsten metal polisher have a uSeable
`lifetime of only about 5,000 to 7,000 wafers. While nickel/
`chromium is generally considered a chemically-resistant
`alloy, the Slurries used to planarize metal layers, especially
`tungsten, are very corrosive. As a consequence, the chemi
`cals of the slurry attack the nickel/chromium Setting alloy
`and, over time, loosen the diamond crystals, causing them to
`fall out of the polishing Surface. Of course, this reduces the
`effective Surface area of the conditioning wheel and Slows
`the conditioning process.
`Accordingly, what is needed in the art is a conditioning
`wheel that is highly resistive to the effects of the corrosive
`oxidants primarily found in metal polishing slurries.
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`SUMMARY OF THE INVENTION
`To address the above-discussed deficiencies of the prior
`art, the present invention provides a method of manufactur
`ing a Semiconductor device using a polishing apparatus
`having a polishing pad conditioning wheel. In one
`65
`embodiment, the polishing pad conditioning wheel com
`prises a conditioning head, a Setting alloy, an abrasive
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`60
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`2
`material, and a corrosion resistant coating. The conditioning
`head has opposing first and Second faces with the first face
`being coupleable to the polishing apparatus. The Setting
`alloy is coupled to the conditioning head at the Second face,
`and the abrasive material is embedded in the Setting alloy,
`which is Substantially covered by the corrosion resistant
`coating.
`Thus, in a broad Scope, the present invention provides a
`protective, corrosion-resistant coating on otherwise
`corrosion-Vulnerable Setting alloys. As a consequence, the
`Setting alloys are better protected by the corrosion-resistant
`coating and its oxidized by-products So that the integrity of
`the corrosion-resistant coating is not jeopardized, which
`would ultimately result in dislodging of the abrasive mate
`rial. While the discussion regarding the present invention is
`directly oriented toward preventing the deleterious effects of
`metal polishing Slurries, it should be readily apparent to one
`who is skilled in the art that the invention is equally
`applicable to other, leSS damaging, polishing slurries.
`In one particularly advantageous embodiment, the corro
`Sion resistant coating is a chromium/aluminum/yttrium
`alloy. In one aspect of this particular embodiment, the
`chromium/aluminum/yttrium alloy may be either a nickel/
`chromium/aluminum/yttrium alloy or a cobalt?chromium/
`aluminum/yttrium alloy. The coating is highly corrosion and
`oxidation resistant.
`The Setting alloy is preferably a hard facing metal alloy,
`Such as a nickel/chromium/iron alloy. Example of Some
`suitable hard facing metal alloys are: Incone1(R) 718,
`Incone1(R) 718 LC, Hastelloy(R), and Illium-R(R). Other use
`able hard facing alloys of well known stainless steels (SS)
`include: 309 SS, 347 SS, 430 SS, and 18-8 stainless steel. In
`one particular embodiment, the corrosion resistant coating is
`highly adherent to the Setting alloy.
`The abrasives employed in the present invention are well
`known to those who are skilled in the art and include
`abrasives, Such as diamonds. Other abrasives typically used
`on conditioning rings, however, are also within the Scope of
`the present invention.
`The foregoing has outlined, rather broadly, preferred and
`alternative features of the present invention So that those
`skilled in the art may better understand the detailed descrip
`tion of the invention that follows. Additional features of the
`invention will be described hereinafter that form the subject
`of the claims of the invention. Those skilled in the art should
`appreciate that they can readily use the disclosed conception
`and Specific embodiment as a basis for designing or modi
`fying other Structures for carrying out the same purposes of
`the present invention. Those skilled in the art should also
`realize that Such equivalent constructions do not depart from
`the Spirit and Scope of the invention in its broadest form.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`For a more complete understanding of the present
`invention, reference is now made to the following descrip
`tions taken in conjunction with the accompanying drawings,
`in which:
`FIG. 1 illustrates a sectional view of a conventional
`Semiconductor polishing pad conditioning head;
`FIG. 2 illustrates a sectional view of one embodiment of
`a Semiconductor polishing pad conditioning head con
`Structed according to the principles of the present invention;
`FIG. 3 illustrates a sectional view of the polishing pad
`conditioning head of FIG. 2 following exposure to an
`oxidizing environment, and
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`

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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 6 of 7 PageID #: 157
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`US 6,281,129 B1
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`3
`FIG. 4 illustrates a partial sectional view of a conventional
`integrated circuit that can be manufactured using a polishing
`pad conditioning wheel constructed in accordance with the
`principles of the present invention.
`DETAILED DESCRIPTION
`Referring initially to FIG. 1, illustrated is a sectional view
`of a conventional Semiconductor polishing pad conditioning
`head 100. The conventional semiconductor polishing pad
`conditioning head 100 comprises a conditioning head 110,
`abrasive crystals 120, and a setting alloy 130. The setting
`alloy 130 is coupled to the conditioning head 110 and holds
`the abrasive crystals 120 in place on a face 111 of the
`conditioning head 110. In a typical conventional
`embodiment, the abrasive crystals are diamond crystals.
`During conditioning, the Setting alloy 130 comes in contact
`with oxidizers remaining from polishing metal, e.g.,
`tungsten, layers of Semiconductor wafers. The corrosive
`effects of the strong oxidizers needed for tungsten CMP
`erodes the setting alloy 130 and causes diamond crystals 120
`to fall from the setting alloy 130 as shown at locations 140.
`Referring now to FIG. 2, illustrated is a sectional view of
`one embodiment of a Semiconductor polishing pad condi
`tioning head 200 constructed according to the principles of
`the present invention. The Semiconductor polishing pad
`conditioning head 200 comprises a conditioning head 210,
`abrasive crystals 220, a setting alloy 230, and a corrosion
`resistant coating 240 located over the setting alloy 230. In
`one embodiment, the Setting alloy 130 is a hard facing metal
`alloy, e.g., a nickel/chromium/iron alloy. In one advanta
`geous embodiment, the abrasive crystals are diamonds. Of
`course, one who is skilled in the art will recognize that
`abrasive crystals other than diamonds may also be used.
`In one embodiment, the setting alloy 230 is preferably a
`hard-facing alloy, Such as a nickel/chromium/iron alloy.
`However, in other embodiments, the setting alloy 230 may
`be a hard-facing alloy Such as StainleSS Steel. Commonly
`known stainless Steels (SS) that may be used in the present
`invention may include: 309 SS, 347 SS, 430 SS, or 18-8 SS.
`Alternatively, the Setting alloy 230 may comprise commer
`cially available alloys such as: Inconel(R) 718, Incone1(R) 718
`LC, Hastelloy(R), or Illium-R(R). In one particularly advanta
`geous embodiment, the corrosion-resistant coating 240 com
`prises a chromium/aluminum/yttrium alloy. Specific alter
`native embodiments of the corrosion-resistant coating 240
`include nickel/chromium/aluminum/yttrium or cobalt/
`chromium/aluminum/yttrium alloys.
`Referring now to FIG. 3, illustrated is an enlarged Sec
`tional view of the polishing pad conditioning head 200 of
`FIG. 2 following exposure to an oxidizing environment.
`When the polishing pad conditioning head 200 is exposed to
`oxidizing conditions during conditioning of a metal
`polishing pad, it is believed that yttrium disperses and aides
`in pinning the grain boundaries in the corrosion-resistant
`coating 240, while the aluminum and chromium of the
`corrosion-resistant coating 240 form their respective oxides,
`e.g., Al2O, Cr2O, etc. Because of the yttrium dispersion,
`the oxides are able to form an adherent oxide layer 340 on
`the corrosion-resistant coating 240. This oxide layer 340,
`therefore, enables the setting alloy 230 to resist corrosion
`better than a conventional configuration of a bare Setting
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`4
`alloy 130 as described in FIG. 1, and thereby improve the
`useable lifetime of the conditioning head 200.
`Referring now to FIG. 4, illustrated is a partial sectional
`view of a conventional integrated circuit 400 that can be
`manufactured using a polishing pad conditioning wheel
`constructed in accordance with the principles of the present
`invention. In this particular Sectional view, there is illus
`trated ah active device 410 that comprises a tub region 420,
`Source/drain regions 430 and field oxides 440, which
`together may form a conventional transistor, Such as a
`CMOS, PMOS, NMOS or bi-polar transistor. A contact plug
`450 contacts the active device 410. The contact plug 450 is,
`in turn, contacted by a trace 460 that connects to other
`regions of the integrated circuit, which are not shown. AVIA
`470 contacts the trace 460, which provides electrical con
`nection to Subsequent levels of the integrated circuit.
`Although the present invention has been described in
`detail, those skilled in the art should understand that they can
`make various changes, Substitutions and alterations herein
`without departing from the Spirit and Scope of the invention
`in its broadest form.
`What is claimed is:
`1. A method of manufacturing a Semiconductor device,
`comprising:
`polishing a Semiconductor wafer with a chemical/
`mechanical Slurry against a polishing pad, the polishing
`forming variations in a polishing Surface of the polish
`ing pad; and
`conditioning the polishing Surface with a polishing pad
`conditioning wheel comprising:
`a conditioning head having opposing first and Second
`faces, the first face coupleable to a polishing appa
`ratus,
`a Setting alloy coupled to the conditioning head at the
`Second face;
`abrasive material embedded in the Setting alloy; and
`a corrosion resistant coating affixed to the Setting alloy.
`2. The method as recited in claim 1 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the corrosion resistant coating comprises a
`chromium/aluminum/yttrium alloy.
`3. The method as recited in claim 2 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the chromium/aluminum/yttrium alloy com
`prises a nickel/chromium/aluminum/yttrium alloy.
`4. The method as recited in claim 2 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the chromium/aluminum/yttrium alloy com
`prises a cobalt/chromium/aluminum/yttrium alloy.
`5. The method as recited in claim 1 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the Setting alloy comprises a hard facing
`metal alloy.
`6. The method as recited in claim 5 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the Setting alloy comprises a nickel/
`chromium/iron alloy.
`7. The method as recited in claim 5 wherein conditioning
`includes conditioning with a polishing pad conditioning
`wheel wherein the hard facing metal alloy is Selected from
`the group consisting of:
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`Case 2:20-cv-00048-JRG Document 1-4 Filed 02/21/20 Page 7 of 7 PageID #: 158
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`US 6,281,129 B1
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`S
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`5
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`Inconel(R) 718,
`Inconel(R) 718 LC,
`Hastelloy(R),
`Illium-R(R),
`309 Stainless Steel,
`347 Stainless Steel,
`430 Stainless Steel, and
`18-8 Stainless Steel.
`8. The method as recited in claim 1 wherein conditioning 1O
`includes conditioning with an abrasive material comprising
`diamonds.
`9. A method for manufacturing an integrated circuit,
`comprising:
`forming active devices on a Semiconductor wafer and
`forming a Substrate over the active devices,
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`positioning a Semiconductor wafer in a polishing appa
`ratus having a polishing Surface, the polishing Surface
`having been conditioned with a polishing pad condi
`tioning wheel comprising:
`a conditioning head having opposing first and Second
`f
`th E. tf
`E; s
`lishi
`e IIrS Iace coupleable to line pollSning appa
`a Setting alloy coupled to the conditioning head at the
`Second face;
`abrasive material embedded in the Setting alloy; and
`a corrosion resistant coating affixed to the Setting alloy;
`and
`polishing the Substrate against the polishing Surface using
`the slurry.
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