Ex Parte so et al

Board of Patent Appeals and Interferences

Jan 4, 2008

10454877 (B.P.A.I. Jan. 4, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte JOSEPH K. SO
and TERENCE M. THOMAS
____________

Appeal 2007-3967
Application 10/454,877
Technology Center 1700
____________

Decided: January 4, 2008
____________

Before BRADLEY R. GARRIS, THOMAS A. WALTZ, and
PETER F. KRATZ , Administrative Patent Judges.

GARRIS, Administrative Patent Judge.

DECISION ON APPEAL

Appellants appeal under 35 U.S.C. § 134 from the Examiner's
decision rejecting claims 29-38. We have jurisdiction under 35 U.S.C. § 6.
We REVERSE.
Appellants claim a method for removing copper (I)-BTA complex
precipitate comprising polishing a microelectronic substrate in a manner
such that the precipitate is formed, introducing a copper polishing cleaning
Appeal 2007-3967
Application 10/454,877

solution to dissolve the precipitate and form copper (I) ions, wherein the
cleaning solution includes an amino acid complexing agent having a dipole
ion structure, forming a complex between the copper ions and the
complexing agent, and maintaining the copper ions in solution with the
complexing agent to prevent the copper ions from redepositing on the micro-
electronic substrate.
Representative claim 29 reads as follows:
29. A method useful for removing copper(Ι)-BTA complex
precipitate from substrates and polishing pads comprising the steps of:

polishing a microelectronic substrate in a manner wherein the
concentration of copper ions exceeds the solubility constant (Ksp) and copper
ions react with BTA to form the copper(I)-BTA complex precipitate on the
microelectronic substrate;

introducing a copper polishing cleaning solution to dissolve the
copper(I)-BTA complex precipitate and form copper(I) ions in the cleaning
solution, the copper polishing cleaning solution having an amino acid
complex agent, the complexing agent having a dipole ion structure;

forming a complex between the copper ions and the complexing
agent; and

maintaining the copper ions in solution with the complexing agent to
prevent the copper ions from redepositing on the microelectronic substrate.

The references set forth below are relied upon by the Examiner as
evidence of obviousness:
Kakizawa1 WO 01/71789 A1 Sep. 3, 2001

1 As an English language equivalent to WO 01/71789, the Examiner and
Appellants rely on and refer to Patent Application Publication US
2003/0083214 A1 to Kakizawa et al. (Kakizawa). We shall do likewise.
2
Appeal 2007-3967
Application 10/454,877

Wojtczak 6,344,432 B1 Feb. 5, 2002
Kakizawa US 2003/0083214 A1 May 1, 2003
Kondo 6,561,883 B1 May 13, 2003
Pasqualoni 6,749,488 B2 Jun. 15, 2004

Under 35 U.S.C. § 103(a): claims 29-32 are rejected as being
unpatentable over Wojtczak in view of Kondo or Pasqualoni, and claims
29-38 are rejected as being unpatentable over Kakizawa in view of Kondo or
Pasqualoni.
The Examiner considers each of Wojtczak and Kakizawa to disclose a
post-CMP (i.e., chemical mechanical polishing) composition for cleaning a
microelectronic substrate but acknowledges that neither of these references
teaches removing copper(I)-BTA precipitate specifically from a
microelectronic substrate (Ans. 3, 5). In this latter regard, the Examiner
asserts that the CMP compositions of either Kondo or Pasqualoni would
necessarily form the aforementioned precipitate (Ans. 4, 5) and that it would
have been obvious to follow the CMP methods of Kondo or Pasqualoni with
the post-CMP cleaning methods of Wojticzak (id.) or Kakizawa (Ans. 6),
thereby resulting in a method corresponding to the method defined by
independent claim 29.
These rejections are deficient in a number of respects.
First, we agree with Appellants (App. Br. 6-8; Reply Br. 2-3) that
neither Kondo nor Pasqualoni expressly or inherently teaches the formation
of copper(I)-BTA complex precipitate. As emphasized by Appellants and
explicitly recited in claim 29, the formation of this precipitate requires more
than simply the presence of a certain BTA concentration. An additional
requirement is polishing the microelectronic substrate in such a manner that
3
Appeal 2007-3967
Application 10/454,877

"the concentration of copper ions exceeds the solubility constant (Ksp)"
(claim 29). There is no disclosure in Kondo or Pasqualoni which supports
the proposition that both of these requirements are satisfied such that the
CMP methods of these references would necessarily and inherently form
copper (I)-BTA complex precipitate as asserted by the Examiner.
The Examiner's rejections also are deficient with respect to the
Wojtczak and Kakizawa references. This is because the compositions of
these references comprise numerous alternative ingredients which may or
may not include an ingredient corresponding to Appellants' claimed amino
acid complexing agent having a dipole ion structure. We appreciate the
Examiner's point (Ans. 6-7) that the compositions of Wojtczak and
Kakizawa may include glycine which is one of the complexing agents
encompassed by claim 29. However, glycine is only one of many alternative
ingredients disclosed by Wojtczak (cols. 3-4) and Kakizawa (¶ 0058).
Significantly, the Examiner does not dispute Appellants' argument (App. Br.
7-8) that a number of these alternative ingredients would not satisfy the
complexing agent requirement of the appealed claims.
In summary, none of the applied references contains any teaching or
suggestion of the Appellants' claimed copper(I)-BTA complex precipitate or
a method of treating this precipitate as required by the appealed claims. It is
conceivable that the CMP methods of Kondo or Pasqualoni might be
practiced in such a way that these precipitates would be formed by
happenstance. However, the disclosures of these references do not support
the proposition that such precipitates inevitably would form in practicing the
CMP methods of Kondo or Pasqualoni. Similarly, while the numerous
4
Appeal 2007-3967
Application 10/454,877

composition ingredients of Wojtczak and Kakizawa include glycine, one of
the here claimed complexing agents, there is nothing in the applied
references which would have motivated an artisan to select this particular
ingredient and then use the resulting composition to clean a substrate having
copper(I)-BTA complex precipitate unknowingly formed thereon when
practicing the Kondo or Pasqualoni methods in such a way that the
precipitate is formed by happenstance.
Under these circumstances, we are convinced that the Examiner's
rejections have been formulated by the unwitting application of hindsight,
for the references themselves contain no suggestion for combining and
practicing the selected teachings thereof in a way which would yield the
Appellants' claimed method. We cannot sustain, therefore, either of the
§ 103 rejections advanced by the Examiner on this appeal.
The decision of the Examiner is reversed.
REVERSED

cam

ROHM AND HAAS ELECTRONIC
MATERIALS CMP HOLDINGS, INC.
451 BELLEVUE ROAD
NEWARK, DE 19713
5