U.S. Expr
`.
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`'2 Mail No. EL372083921US
`.rney Docket No.: AM-1776
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`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
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`§
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`§ D
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`GROUP ART UNIT: 1753
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`EXAMINER:
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`.1. Mercado
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`Attorney Docket No.:
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`AM-1776
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`ate:
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`February 1, 2000
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`/4
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`9&7;
`.f 3
`19//5700
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`RE APPLICATION OF: Peijun Ding et al.
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`SERIAL NO.: 08/995,108
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`FILED: December 19, 1997
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`FOR: A TAILORED BARRIER LAYER WHICH
`PROVIDES IMPROVED COPPER INTERCONNECT
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`ELECTROMIGRATION RESISTANCE
`
`AMENDMENT "A"
`UNDER 37 C.F.R.
`1.111
`
`Hon. Assistant Commissioner of Patents
`
`Washington, D.C. 20231
`
`Sir:
`
`This Amendment “A” is in response to the Office Action mailed September 2, 1999, having
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`a shortened statutory period for response of December 2, 1999. A Petition for a two month
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`extension oftime to reply accompanies this Amendment “A”, to extend the time to respond through
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`February 2, 1000.
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`Claims 1 - 27 are pending in the application.
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`CERTIFICATE OF MAILING UNDER 37 CFR 1.10
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`I
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`83
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`{"71
`Pdstal 2
`I hereby certify that this paper and any documents said to accompany this paper are being deposited with the
`Service on the date shown below with sufficient postage as U.S. EXPRESS MAIL NO. EL372083921US in afenvelgpe {T1
`addressed to the: Assistant Commissioner for Patents, Box Non-Fee Amendment, Washington DC 20231.
`g C]
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`////z/;/cg
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`hurchi, Reg. No.31 ,858
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`Date: February 1, 200006995108
`OE/16/2000 tiiiIICli1_L 00000001 110300
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`01 i-"C2102
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`""""7a:W1:rr""'""""'“““""'"'“""'"""""'“"""""“'""""""'““"""""""""""""
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`Page 1 Of 22
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`IP Bridge Exhibit 2002
`TSMC v. IP Bridge
`|FfR20\1 6-O1
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`U.S. Exp’ ‘ ‘°. Mail No. EL372083921US
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`rney Docket No.: AM-1776
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`.,
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`Claims 1 - 27 are subject to restriction requirement.
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`Claims 21 - 27 are rejected under 35 USC § 112, first paragraph, as containing subject matter
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`which was not described in the specification in such a way as to enable one skilled in the art to which
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`it pertains, or with which it is most nearly connected, to make and/or use the invention.
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`Claims 22 and 24 - 26 are rejected under 35 USC § 112, first paragraph, as being dependent
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`upon a rejected base claim.
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`Claims 21 - 27 are rejected under 35 USC § 112, second paragraph, as being indefinite for
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`failing to particularly point out and distinctly claim the subject matter which applicant regards as the
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`invention.
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`Claims 22 and 24 - 26 are rejected under 35 USC § 112, second paragraph, as being dependent
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`upon a rejected base claim.
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`Claims 8 - 11, 14, 15, and 17 are rejected under 35 USC § 102(b) as being anticipated by U.S.
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`Patent No. 5,281,485, to Colgan et al.
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`Claims 8 - 17 are rejected under 35 USC § 103(a) as being unpatentable over U.S. Patent No.
`
`5,391,517, to Gelatos et al., in combination with U.S. Patent No. 5,676,587, to Landers et al.
`
`Claims 8 - 17 and 21 - 26 are rejected under 35 USC § 103(a) as being unpatentable over U.S.
`
`Patent No. 4,985,750, to Hoshino, in view of Landers et al.
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`Claims 8 — 17 are rejected under 35 USC § 103(a) as being unpatentable over U.S. Patent No.
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`5,240,880, to Hindman et al., in view of either Landers et al. or Hoshino.
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`Claims 12, 13, and 16 are rejected under 35 USC § 103(a) as being unpatentable over Colgan
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`et al., in view of either Landers et al., Gelatos et al., or Hoshino.
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`Claims 18 - 20 are rejected under 35 USC § 103(a) as being unpatentable over Gelatos et al.,
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`in combination with Landers et al., as applied to Claims 8 - 17, above, and further in view of U.S.
`
`Patent No. 5,707,498, to Ngan.
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`Page 2 of 22
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`Page 2 of 22
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`U.S. Exp"“s Mail No. EL372083921US
`mey Docket No.: AM-1776
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`Claims 18 - 20 and 27 are rejected under 35 USC § 103(a) as being unpatentable over Hoshino,
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`in view of Landers et al., as applied to Claims 8 - 17, above, and further in view of Ngan.
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`Claims 18 - 20 are rejected under 35 USC § 103(a) as being unpatentable over Colgan et al.,
`
`in view of either Landers et al., Gelatos et al., or Hoshino, as applied to Claims 12, 13, and 16,
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`above, and further in view of Ngan.
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`Please amend the application as follows:
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`IN THE SPECIFICATION:
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`/
`:/
`/
`Page Kane 7, prior to "crystallog phic", please delete "{111}" and insert - - <111>- -;
`/
`line , prior to "conte1‘t/,})lease delete "{1 1}", and insert - - <111>; and,
`line 1
`, prior to "crysta‘I",/1)lease delete ''{11 %d insert - - <11’l>/— -.;
`Page Sffie 1, 2é"aluminum", please delete "{111 ", and ' .sert - - <1 1> - -;
`line 1
`, prior to "crystalkrfise delete "{111 ", and insert - - <1
`— - ; and,
`line 1
`, after "high", please delete "{1 1141 insert- - <11 > - -.
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`Page 6, after line 17 and prior to line 18, please insert the following as a new paragraphs.
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`- - We have also developed a method of producing a copper interconnect structure comprising a
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`copper layer deposited over a barrier layer structure of the kind described above, comprising a Ta
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`layer overlying a TaNx layer, where the Cu <11 1> crystallographic content is at least 70 % of the Cu
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`<111> crystallographic content which can be obtained by depositing the copper layer over a pure
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`Ta barrier layer which is about 500 A thick. The method comprises the steps of :
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`a) depositing a first layer of TaNx having a thickness ranging from greater than about 50 A to
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`about 1,000 /3.;
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`b) depositing a second layer of Ta having a thickness ranging from about 5 A to about 500 A
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`over the surface of the first layer of TaNx; and
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`c) depositing a third layer of copper over the surface of the second layer of Ta, wherein at least
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`a portion of the third layer of copper is deposited using a physical vapor deposition technique, and
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`Page 3 of 22
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`Page 3 of 22
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`U.S. Exp "‘ Mail No. EL372083921US
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`wherein the substrate temperature at which the third layer of copper is deposited is less than about
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`500°C.
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`Further, we have developed a method of producing a copper-comprising contact via structure
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`comprising a copper layer deposited over a barrier layer structure of the kind described above,
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`comprising a Ta layer overlying a TaN, layer, wherein the Cu <1 11> crystallographic content is at
`
`least 70 % of the Cu <1l1> crystallographic content which can be obtained by depositing said
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`copper layer over a pure Ta barrier layer which is about 300 A thick. The method comprises the
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`steps of:
`
`#4,
`
`.
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`I
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`a) depositing a first layer of TaNx having a thickness ranging from greater than about 10 A to
`,
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`about 300 A;
`b) depositing a second layer of Ta having a thickness ranging from about 5 A to about 300 A
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`over the surface of said first layer of TaNx; and
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`c) depositing a third layer of copper over the surface of the second layer of Ta, wherein at least
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`a portion of the third layer of copper is deposited using a physical vapor deposition technique, and
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`wherein the substrate temperature at which the third layer of copper is deposited is less than about
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`500°C.
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`In the method of producing a copper-comprising contact structure described above, a least
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`a portion of the first layer of TaN,, or the second layer of Ta, or the third layer of Cu, or at least a
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`portion of more than one of these three layers may be deposited using ion-deposition sputtering,
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`where at least a portion of the sputtered emission is in the form of ions at the time the emission
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`reaches the substrate surface, and where, typically 10 % or more of the sputtered emission is in the
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`form of ions at the time the emission reaches the substrate surface. --
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`Page 6,,lvi{e 21, a'lQ"copper", pleasedefe "{lll/}"'/and insert - - <1/1> — — .
`Pageflfiie 4, afie{"high", please delete "{1l }", and in
`{- <11l> - - .
`Page 12,46 16,
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`er "tantalum", please delete "{O0 }", and insert - - <002> - -; and,
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`Page 4 of 22
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`U.S. Exp ' Mail No. EL372083921US
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`}", and insert - - <111> - - .
`line/Yater "high", please delete "{1
`/
`Page 13, 1344, aft r "copper", please delete "{111}",(and insert - - <11 > - -; and,
`line/8,/ter "copper",'fiQe delete "{111’}",/and insert - - <1 1
`line 10, after "copper", pleaseflgete "{111}", and insert — - <11 > - -;
`/
`
`line léfter "copper",please delete "{11Tfiand insert- - <11§-;
`line léétfter "copper”,/please delete "{111}",/and insert - - <111> - -;
`/
`line 20,611/er "coppefglease delete "{111 ", and insert - - <111> - -; /
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`line 23
`rior to "crystal1ograph'c", please delete "{11 }", and insert - - <111> ~ -.
`Page 14 me 15, pgto "intensity", please delete "{111}
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`"Qinsert--<111>--;
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`line 1
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`, prior to "C S“, please delete "{11
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`line 19, prior to "orientation", please delete "{11
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`line 2 , prior to "FWH ", please delete "{1
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`', and insert - - <
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`1> - -;
`J
`, and insert - - <111> - - ; and,
`/
`", and insert - - <111> - - .
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`Page 15,’line 8, gr to '(ysta1lographic", plefidelete "fllfi and i . sert - - <111> - - ;
`1ine13,/after "Cu' , please delete "{1l1}", and insert - - <1 1 1>
`line 1
`, after "Cu", please delete "{111 ', and insert - - <117'
`line 2 ,after"Cu",1£1se delete "{11,1’}",/and/insert — - <11 //
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`> _ _.
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`insert - - <111>- -' “d
`line 2 , after "C ‘, please delete "{111 ",
`.
`.
`/
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`d
`rt——<111>--.
`,
`fte "C ,1
`d1t"111",
`an mse J
`me
`u p ease e e e
`a
`r
`{
`}
`Page 16 me 3, af@Cu", pl
`se delete "{111} , and insert - - <111> - -'
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`1
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`line , after "Cu", pl
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`se delete "{1l1}", and insert - - <111> - -;
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`line 11@"Cu",1)l/asedelete"{111f§2l’insert-—411%
`line14 u",pleasedelete"{111}',and' sert—-<14
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`
`- —v;’and
`line 15,
`ftei‘/"c<;p;§er", please delete "{11
`", and insert — — <111
`lin
`9‘,after "high",pl
`A we "{’ 11}",andinsert- -<11‘1/. K
`Page ct), line 2 gh", please delete "{111’1",/and insert - - <111> - -.
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`U.S. Exp
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`Mail No. EL372083921US
`rney Docket No.: AM-1776
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`IN THE CLAIMS:
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`Please cancel Claims 1 - 7 without prejudice, as being to a non-elected invention.. Please
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`amend Claims 8, 21, 23, and 27 as follows.
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`Claims not being amended are presented in italicsfor reference purposes only.
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`
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`8.
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`(Once Amended) A method ofproducing a combined barrier layer and wetting layer structure
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`[useful] which is used in combination with a conductive layer, said method comprising the steps of:
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`a)
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`depositing a first layer of TaNx having a thickness ranging from greater than about 10 A
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`to about 1,000 A; [and]
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`b)
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`depositing a second layer of Ta having a thickness ranging from about 5 A to about
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`;4a2
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`500 A; and
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`c)
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`depositing a conductive layer over a surface of said second layer of Ta wherein the
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`substrate temperature during said conductive layer deposition and in subsequent processing steps is
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`less than about 500 °C .
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`
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`9. (Once Amended) The method of Claim 8, wherein [the] @ conductive layer is copper.
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`I 0. The method ofClaim 8, wherein saidfirst layer of TaN, is deposited upon a substrate having
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`a substrate temperature rangingfrom about 25 °C to about 500 °C.
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`11. The method ofClaim 8, wherein said second layer of Ta is deposited upon a substrate having
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`a substrate temperature rangingfiom about 25 °C to about 500 ‘’C.
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`Page 6 of 22
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`C057?»
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`12.
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`(Once
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`ended) ThemethodofClaim 8,whereinsaidbarrierlayerisused inaninterconnect
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`structure, and herein the thickness of said TaN,, layer ranges from about 50 /°\ to about 1,000 /3\ and
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`}43 the thickness 0 said Ta layer ranges from about 20 /°\ to about 500 /3\.
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`13.
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`(Once Amended) The method of Claim 8, wherein said combined barrier layer and wetting
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`layer structure is used in a contact via structure, and wherein the thickness of said TaNx layer ranges
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`from about 10 A to about 300 A and the thickness of said Ta layer ranges from about 5 A to about
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`300 /3..
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`14. The method ofClaim 8, or Claim 12, or Claim 13, where x ranges"from about 0.1 to about 1.5.
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`15. The method of Claim 8, wherein at least a portion of said Ta layer is deposited using a
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`traditional, standard sputtering technique.
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`16. The method of Claim 12, wherein at least a portion of said Ta layer is deposited using a
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`traditional, standard sputtering technique.
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`II ‘
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`ll 1 j
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`(Once Amended) The method of Claim 8, wherein at least a portion of [the] @ TaN, layer
`17.
`is deposited using a traditional, standard sputtering technique.
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`18. The method of Claim 8, wherein at least a portion of said Ta layer is deposited using ion-
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`deposition sputtering.
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`19. The method of Claim 13, wherein at least a portion ofsaid Ta layer is deposited using ion-
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`deposition sputtering.
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`Page 7 of 22
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`20.
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`(Once Amended) The method of Claim 8, wherein at least a portion of [the] gig TaNx layer
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`is deposited using ion-deposition sputtering.
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`21.
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`(Once Amended) A method of producing a copper interconnect structure comprising [the] a
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`combined TaN,,/41 barrier layer and wetting layer, [of Claim 1] and an overlying copper layer,
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`wherein the Cu [{l1 1}] i crystallographic content of said overlying copper layer is at least 70
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`% of the Cu [{1l1}] i crystallographic content which can be obtained by depositing said
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`copper layer [using] E; a pure Ta barrier layer which is about 500 A thick, said method comprising
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`2416-’ the steps of:
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`a)
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`depositing a first layer of TaN,, having a thickness ranging from greater than about 50 A
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`to about 1,000 A;
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`b)
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`depositing a second layer of Ta having a thickness ranging from about 5 A to about
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`500 A over the surface of said first layer of TaNx ; and
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`c)
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`depositing a third layer of copper over the surface of said second layer of Ta, wherein at
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`least a portion of said third layer of copper is deposited using a physical vapor deposition technique,
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`and wherein the substrate temperature at which said third layer of copper is deposited is less than
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`about 500°C.
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`22. The method of Claim 21, wherein said copper interconnect structure is annealed at a
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`temperature ofless than about 500 °C.
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`
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`23.
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`(Once Amended) A method ofproducing a copper—comprising contact via structure comprising
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`[the] a combined TaNx@ barrier layer and wetting layer, [of Claim 1] and an overlying copper
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`layer, wherein the Cu [{111}] < 11 1 > crystallographic content of said overlying copper layer is at
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`least 70 % ofthe Cu {l 1 1 } crystallographic content which can be obtained by depositing said copper
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`1
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`layer [using] over a pure Ta barrier layer which is about 300 A thick, said method comprising the
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`steps of:
`
`a)
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`depositing a first layer of TaNx having a thickness ranging from greater than about 10 A
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`/%é to about 300 /°\;
`{
`b)
`depositing a second layer of Ta having a thickness ranging from about 5 A to about
`W 300 A over the surface ofsaid first layer ofTaNx ; and
`c)
`depositing a third layer of copper over,the surface of said second layer ofTa, wherein at
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`least a portion of said third layer of copper is deposited using a physical vapor deposition technique,
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`and wherein the substrate temperature at which said third layer of copper is deposited is less than
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`about 500°C.
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`24. The method of Claim 23, wherein said contact-comprising structure is annealed at a
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`temperature ofless than about 500 °C.
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`25. The method ofClaim 23, wherein said copper layer is deposited at a temperature ofless than
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`about 3 00 °C.
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`26. The method ofClaim 25, wherein said structure is annealed at a temperature ofless than about
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`500 °C.
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`27.
`(Once Amen d) A method of producing a copper-comprising contact structure comprising
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`7 [the] a combined Ta
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`a barrier layer and wetting layer, [of Claim 1] and an overlying copper
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`layer, wherein the Cu [{1 1}] < ll1> crystallographic content of said overlying copper layer is at
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`least 70 % of the Cu [{111} <111> crystallographic content which can be obtained by depositing
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`comprising the steps of:
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`said copper layer [using] ver a pure Ta barrier layer which is about 300 A thick, said method
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`er of TaNx having a thickness ranging from greater than about 10 A
`depositing a first 1
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`a)
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`to about 300 A;
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`b)
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`depositing a second la er of Ta having a thickness ranging from about 5 A to about
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`247
`300 A over the surface of said first ayer of TaN,( ; and
`[’m7“J
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`(
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`0)
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`depositing a third layer of opper over the surface of said second layer of Ta, wherein at
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`least a portion of said third layer of cop
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`r is deposited using a physical vapor deposition technique,
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`
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`and wherein the substrate temperature at hich said third layer of copper is deposited is less than
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`about 500 °C,
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`
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`wherein at least a portion of said first lay , or said second layer, or said third layer, or a portion
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`o_f_a combination of said layers [thereof], is de
`sited using ion-deposition sputtering.
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`REMARKS
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`Applicants hereby confirm the election of Group II, Claims 8 - 27, made in view ofa restriction
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`requirement, during a telephone conversation between Examiner Jason Resnick ofArt Unit No. 1 775
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`and the undersigned attorney of record on August 5, 1999. The Group I claims, Claims 1 - 7 are
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`canceled herein, without prejudice, as being non-elected claims under the restriction requirement.
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`Prosecution of Claims 1 - 7 will be pursued in a subsequently filed divisional application.
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`The Specification has been amended to include a portion of the invention which was disclosed
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`in independent Claims 21 , 23, and 27 at the time ofthe application was originally filed. In particular,
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`the subject matter of independent Claims 21, 23, and 27 from the originally~filed application has
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`been inserted into the Summary of the Invention. Applicants may, as a matter of right, subsequently
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`add to the Specification (Summary ofInvention) the subject matter which was disclosed in originally
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`filed Claims 21 - 27.
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`U.S. Exp "9 Mail No. EL372083921US
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`Claims 8 - 27 are presently pending in the application. In order to advance the prosecution of
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`the present application, Claim 8 has been amended to recite that
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`the first layer of TaNx and the
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`second layer of Ta together form a combined barrier layer and wetting layer useful in combination
`with a conductive layer. This amendment should not be construed as agreement with or
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`acquiescence to the Examiner’s grounds for rejection of any of the claims in the application. All of
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`the amendments to the claims set forth above are fully supported by the specification and drawings
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`as originally filed.
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`Both the Specification and the Claims have been amended to correct a formal matter, where
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`the {
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`} bracketing of the crystallographic content lattice numbers has been replaced with < >
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`bracketing, which is recognized in the art as being the more technically correct form of bracketing.
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`Claim Rejections Under 35 USC § 112
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`Claims 21 - 27 are rejected under 35 USC § 112, first paragraph, as containing subject matter
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`which was not described in the specification in such a way as to enable one skilled in the art to which
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`it pertains, or with which it is most nearly connected, to make and/or use the invention. The
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`Specification has been amended to include the subject matter of Claims 21, 23, and 27, which
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`subject matter was a part of the disclosure in the application as originally filed. Claims 21, 23, and
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`27 recite that if one skilled in the art follows applicants’ method, a Cu <11l> crystallographic
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`content of at least 70% will be obtained. This is all that is necessary to enable one skilled in the art
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`to make and/or use the invention. One skilled in the art is able to make a copper interconnect
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`structure (Claim 21) or a copper-comprising via structure (Claims 23 and 27) having a copper
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`crystalline structure which is at least 70 % <1l1> in content by following the method steps. One
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`skilled in the art will know how to use the interconnect or the contact via, as the use is well
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`established in the art.
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`U.S. Exp ~ Mail No. EL372083921US
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`The Examiner may be inquiring about how one skilled in the art (or applicants) knows that a
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`crystalline structure having at least 70 % <1 11> is obtained when the method is followed. There is
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`a direct correlation between the data provided in Figure 2 and the copper <1 1 l> content. Applicants
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`provided the intensity and FWHM data combination rather that the calculated copper <1 1 l> content,
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`because they believed a one skilled in the art can better see the directional effect of the changing
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`variables from this data, so that it is more meaningful than the copper <11 1> content which can be
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`calculated based on the data.
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`Claims 22 and 24 - 26 are rejected as being dependent upon a rejected base claim. Applicants
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`believe these claims are now allowable in View of amendment of the Specification and the above
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`explanation.
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`The Examiner is respectfully requested to withdraw the rejection of Claims 21 - 27 under 35
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`USC § 112, first paragraph.
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`Claims 21 - 27 are rejected under 35 USC § 112, second paragraph, as being indefinite for
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`failing to particularly point out and distinctly claim the subject matter which applicant regards as the
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`invention. Claims 21 - 27 include reference to "the barrier layer of Claim 1". Claim 1 has been
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`canceled in response to a Restriction Requirement, thereby rendering the scope of Claims 1 - 27
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`indefinite. Claims 22 and 24 - 26 are rejected under 35 USC § 112, second paragraph, as being
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`dependent upon a rejected base claim.
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`In response to the rejection of Claims 21 - 27 under 35 USC § 112, second paragraph, the
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`description of the structure to be obtained has been amended, and the reference to the "barrier layer
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`of Claim 1" has been removed.
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`In light of the above amendments to Claims 21, 23, and 27, withdrawal of the rejection of
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`Claims 21 — 27 under 35 USC § 112, second paragraph, is respectfully requested.
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`U.S. Exp " Mail No. EL372083921US
`irney Docket No.2 AM-1776
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`All of the amendments to the claims set forth above are fully supported by the amended
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`specification, and by the combination of the specification, claims, and drawings as originally filed.
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`Applicants will now address each ofthe remaining claim rejections based on cited art, as raised
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`by the Examiner.
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`Claim Rejections Under 35 USC § 102
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`Claims 8 - 11, 14, 15, and 17 are rejected under 35 USC § 102(b) as being anticipated by U.S.
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`Patent No. 5,281,485, to Colgan et al.
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`With respect to the rejection over Colgan et al., the Examiner has noted ". . .that the preamble
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`recitation of a barrier layer useful in combination with a conductive layer was not given the effect
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`of a limitation in the claim."
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`In order to advance the prosecution of the present application,
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`independent Claim 8 has been amended to make it clear that applicants are claiming a combined
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`structure including a barrier layer and a wetting layer which is used in combination with a
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`conductive layer. The claimed method is for producing a combined barrier layer and wetting layer
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`structure which is used in combination with a conductive layer, wherein the method comprises
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`particular steps. The method is limited to one which produces the specified combined barrier layer
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`and wetting layer structure used in combination with a conductive layer.
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`Colgan et al. discloses a method ofmaking A1pha—Ta thin films rather than the prior art Beta-Ta
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`thin films. (Abstract, and Col. 1, lines 25 - 30 with Col. 3, lines 60 - 61.) The purpose is to lower
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`the resistivity of the Ta thin film, as illustrated in Figure 2A of Colgan et al. To ensure the
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`formation of Alpha Ta, a seed layer of Ta(N)is deposited on the substrate prior to deposition of the
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`Ta layer. This contrasts with the present invention which relates to a method of forming a three-
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`layer structure including a combined barrier layer and wetting layer structure (Ta/TaN,,) over which
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`a conductive layer is deposited. Applicants’ Claim 8 has been amended to include a step c) in which
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`U.S. Exp
`9 Mail No. EL372083921US
`‘mey Docket No.: AM-1776
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`the conductive layer is deposited over the Ta wetting layer. Typically, the conductive layer is
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`copper, as claimed in Claim 9. When the conductive layer is copper, the purpose of the invention
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`is, as described in the Summary of the Invention, Page 5, lines 16 - 19, to form a Cu layer having
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`a high <1 1 15 crystalline content, so that the electromigration resistance ofthe Cu layer is increased.
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`Thus, applicants’ method includes the deposition of a conductive layer over the Ta layer, which is
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`neither described or suggested in Colgan et al.. When the conductive layer is copper, the copper
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`layer has increased electromigration resistance. This solves a problem pertaining to deposited
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`copper layers which is neither mentioned or contemplated in Colgan et al.
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`In addition, in forming the Ta(N) seed layer, Colgan et al. discloses at Col. 5, lines 22 - 32, that
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`the doped tantalum seed layer is not the same as depositing Ta2N, which requires precise control of
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`the gas composition during the deposition process. This contrasts with applicants’ Claim 14, where
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`the x of TaN,, ranges from about 0.1 to 1.5. In the case of Ta2N, applicants’ x would be about 0.5.
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`Thus, Colgan et al. teaches away from the present invention in teaching that x is not 0.5 or less.
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`In light of the above, withdrawal of the rejection of Claims 8 and 9, and claims which depend
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`therefrom, including Claims 10. 11, 14, 15, and 17 under 35 USC § 102(b), as being anticipated by
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`Colgan et al., is respectfully requested.
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`Claim Rejections Under 35 USC § 103
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`Claims 8 - 17 are rejected under 35 USC § 103(a) as being unpatentable over U.S. Patent No.
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`5,391,517, to Gelatos et al., in combination with U.S. Patent No. 5,676,587, to Landers et al.
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`Gelatos et al. discloses a three-layer "interface layer" structure which overlies the surface of a
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`dielectric layer and comprises, from bottom to top, a first titanium layer, a titanium nitride layer, and
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`second titanium layer.
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`(Abstract, lines 9 - 12.) Although Gelatos et al. suggests that other metals
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`having the necessary adhesive and diffusion barrier characteristics can be employed to form the
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`interface layer, the example provided is the use of titanium or tungsten or tantalum in place of
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`titanium nitride as a diffusion barrier layer, and the use of chrome as the upper metal layer of the
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`interface layer (Col. 3, lines 53 - 60). There is no suggestion of the use of tantalum nitride as the
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`diffusion barrier in combination with an overlying wetting layer of tantalum.
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`With regard to deposition of an overlying copper layer, there is no suggestion that a copper
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`layer having a high <111> crystal orientation be deposited over the interface layer. There is no
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`mention or even a suggestion of using a high <1 1 1> crystal orientatio ._in.the.copper—layer.to.reduQe__.
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`electromigration of the copper. Instead, the emphasis is in creating a copper-titanium intermetallic
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`la p;Er layer to the underlying titanium nitride layer (Col. 5, lines
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`14 - 43.) In order to create the copper-titanium intermetallic layer, Gelatos et al. uses an annealing
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`step. The annealing step is carried out at reduced pressure and at a temperature of about 500 °C -
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`600 °C (Col. 5, lines 26 - 28). In the alternative, Gelatos teaches that armealing may be carried out
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`at a lower temperature of about 400°C to about 500°C in the presence of a forming gas (NZHZ)
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`ambient. Applicants do not need to form a copper-tantalum intermetallic layer, and no annealing
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`step is required after copper deposition, unless a copper seed layer is used and armealing of the
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`combination of seed layer with subsequent copper deposition is necessary. Further, applicants have
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`limited amended Claim 8 to require that the maximum temperature of the copper either during
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`deposition or during subsequent processing is less than 500 °C. Applicants previously explained
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`that 1t1s important to maintain the co per at a temperat‘1‘1r”é"’6f‘500 °C or less, preferably 300 °C or
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`less, since the crystal orientation of the copper is sensitive to temperature. (Specification, Page 6,
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`lines 14 - 17 and limitations in originally filed Claims 21 - 24 and 26). An annealing step,above 500 &
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`°C as recQmmended,by Gelatos et al. would adversely affect the <1l1> content of the deposited
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`copper layer; and therefore, Gelatos et al. teaches away from the present invention.
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`Landers et al. discloses a chemical mechanical planarization method for selectively removing
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`a layer of metallization material such as tungsten or copper and a liner film such as Ti/TiN or
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`Ta/TaN from the surface of an oxide layer of a semiconductor wafer. At Col. 1, lines 38 - 43, the
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`U.S. Exp "s Mail No. EL372083921US
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`"Background Art" section of the Landers et al. patent states: "A thin liner film, generally not more
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`than approximately 1,000 Angstroms thick is then deposited over the oxide layer. The liner
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`generally comprises thin films oftitanium (Ti)) and titanium nitride (TiN) disposed over one another
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`to form a Ti/TiN stack, or tantalum (Ta) and tantalum nitride (TaN) to form a lab} stack." This
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`language indicates that Ti is deposited over the oxide layer, and TiN is deposited over the Ti layer;
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`and, that Ta is deposited over the oxide layer, and TaN is deposited over the Ta layer. This
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`corresponds with the Gelatos et al. disclosure which teaches at Col. 3, lines 40 - 50: "In a preferred
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`embodiment, a first titanium layer 16 overlies the surface ofdielectric layer 12, and a titanium nitride
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`layer 18 overlies first titanium layer 16.
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`. Specifically, titanium nitride layer 18 provides a
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`diffusion barrier preventing the transport of copper into first titanium layer 16 and the underlying
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`dielectric and device layers". By contrast, the present invention is a method for making a TaN /Ta
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`barrier layer. The order of deposition of the tantalum nitride and tantalum is a critical feature of the
` r. =—.ur...;~,. .v(re¢wI -...._...-uc-.v..x—....»..-mu.‘ -.v. :. : ._.. ;g)u
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`method of the present invention. As applicants explained in their Summary of the Invention at
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`Page 5,lli’nesl2 - 198, although TaN, is a better barrier layer for copper thanTa,
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`directly over TaNx does not exhibit a sufficiently high degree of Cu <111> crystal orientation to
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`Combining the disclosure of Gelatos et al. with the disclosure of Landers et al. does not render
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`obvious the present invention. In fact, this combination ofreferences teaches away from the present
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`invention. For the reasons set forth above, applicants respectfully request withdrawal ofthe rejection
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`of Claims 8 - 17 under 35 USC § 103(a), over Gelatos et al., in combination with Landers et al.
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`Claims 8 - 17 and 21 - 26 are rejected under 35 USC § l03(a) as being unpatentable over U.S.
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`Patent No. 4,985,750, to Hoshino, in view of Landers et al.
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`With regard to the disclosure of Hoshino, the Examiner states the following: "Hoshino teaches
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`a method ofproducing barrier layer for the subsequent deposition of an overlaying conductive layer.
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`rney Docket No.: AM-1776
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`In reference to Figure 2, a first layer [20] of the barrier layer is deposited by a traditional sputtering
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`method followed by the deposition of a second layer [22], the second la er bein a Ta la er having
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`a thickness in the range of 500 to 3000 A. A conductive layer of copper [24] is then deposited over
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`the barrier layer (Col. 3 lines 28-66)."
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`It is readily apparent that there is a discrepancy in this
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`description, because if a Ta layer is deposited over the barrier layer, then the copper layer
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`subsequently deposited will not be deposited upon the barrier layer. Upon review of Col. 3, lines
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`28 - 41, of the Hoshino patent, applicants found the following language: "A metallic layer 20 is
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`deposited on the insulating film 18 and on the top ofthe n+-diffused layer 16a in the Si substrate 16
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`through the contact hole 18a. The metallic layer 20 may be made of Ti, Al or platinum (PT), for
`example. . .The metal