Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant's arguments filed have been fully considered but they are not persuasive.
In response to applicant's argument that Kwon grows the barrier layer 143 by oxidation of the lower layer 141, and thus cannot be combined with another material, the test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
In this case, Masanabu gives excellent reason for swapping the TiO layer 143 of Kwon with a SiN layer 15, as detailed below. The person of ordinary skill having the benefit of Kwon and Masanabu may readily decide based on application specific needs which materials to use to arrive at the claimed invention.
Regarding arguments that Kwon teaches away from the disclosure of Masanabu, “the prior art’s mere disclosure of more than one alternative does not constitute a teaching away from any of these alternatives because such disclosure does not criticize, discredit, or otherwise discourage the solution claimed.” MPEP 2143.01(I). Here, Kwon describes the formation of the barrer 143 “In some embodiments of the present inventive concept, the first oxide layer 143 may be formed using natural oxidation by exposing the first barrier layer 141 to an oxygen environment.” [0057]. Not only does this not “criticize, discredit, or otherwise discourage” other solutions, the teaching is left open ended for the person of ordinary skill to explore alternatives. As a result, the rejections stand.
Double Patenting
Applicants state on page 7 of the remarks dated 2/4/2026 that a terminal disclaimer has been filed. However, one does not appear in the file wrapper as of the drafting of this communication. As a result, the obviousness type double patenting rejection presented in the prior action is maintained.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-10 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pat. Pub. No. 20160181412 to Kwon et al. (Kwon) in view of KR 19980033022 to Masanabu and further in view of U.S. Pat. Pub. No. 20120119204 to Wong et al. (Wong).
Regarding Claim 1, Kwon teaches a gate structure, comprising:
a metal layer 150;
a barrier layer 141/142/143 covering a bottom surface and sidewalls of the metal layer, wherein the barrier layer comprises fluorine (tungsten hexafluoride is used to deposit the gate metal and therefore inherently fluorine radicals would become trapped in the barrier layer) and the barrier layer is a tri-layered structure.
Kwon does not explicitly teach that the barrier layer comprises fluorine and silicon, or fluorine and aluminum. However, in analogous art, Masanabu teaches a fluorine diffusion barrier 15 of silicon nitride. It would have been obvious to the person of ordinary skill in the art before the time of filing to modify the teaching of Kwon and replace the TiO layer 143 with the SiN layer 15 of Masanabu in order to prevent W from the gate electrode from diffusing into the gate dielectric, as taught by Masanabu. See also MPEP2144.07; Masanbu recognizes that SiN is suitable as a fluorine diffusion barrier.
Kwon and Masanabu do not explicitly teach a work function layer surrounding the barrier layer. However, in analogous art, Wong teaches a work function layer 37L surrounding a barrier layer 38L. It would have been obvious to the person of ordinary skill in the art before the time of filing to include the teaching of Wong to adjust the work function of a gate structure and increase efficiency, as taught by Wong throughout.
Regarding Claim 2, Kwon, Masanabu and Wong teach the gate structure according to claim 1, wherein the metal layer comprises tungsten Kwon, [0065].
Regarding Claim 3, Kwon, Masanabu and Wong teach the gate structure according to claim 1, wherein the work function layer and the barrier layer respectively exhibit a U-shape in a cross-sectional view (see gate structures of Kwon and Wong).
Regarding Claim 4, Kwon, Masanabu and Wong teach the gate structure according to claim 1, wherein the barrier layer has an inner sidewall and an outer sidewall opposite to the inner sidewall, the inner sidewall of the barrier layer is in physical contact with the metal layer, and the outer sidewall of the barrier layer is in physical contact with the work function layer (see gate structures of Kwon and Wong).
Regarding Claim 5, Kwon, Masanabu and Wong teach the gate structure according to claim 1, wherein the barrier layer comprises:
a first TiN layer 141;
a second TiN layer over the first TiN layer 142; and
a trapping layer sandwiched between the first TiN layer and the second TiN layer, wherein the trapping layer comprises silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, or a combination thereof (SiN of Masanabu).
Regarding Claim 6, Kwon, Masanabu and Wong teach the gate structure according to claim 5, wherein the trapping layer further comprises silicon tetrafluoride (SiF4) or aluminum fluoride (AlF3) (fluorine radicals would inherently form some SiF4 in the SiN trapping layer).
Regarding Claim 7, Kwon, Masanabu and Wong teach the gate structure according to claim 5, wherein the first TiN layer comprises silicon tetrafluoride (SiF4) or aluminum fluoride (AlF3) (SiF4 from the trapping layer would inherently diffuse into the first barrier layer).
Regarding Claim 8, Kwon, Masanabu and Wong teach a fin field-effect transistor (FinFET), comprising:
a semiconductor fin;
a gate structure disposed across the semiconductor fin, wherein the gate structure comprises (Kwon, [0014]):
a metal layer;
a barrier layer, wherein the barrier layer exhibits a U-shape in a cross-sectional view to surround the metal layer, the barrier layer comprises fluorine and silicon, or fluorine and aluminum, and the barrier layer is a tri-layered structure; and
a work function layer, wherein the work function layer exhibits a U-shape in the cross-sectional view to surround the barrier layer; and
a strained material covering a portion of the semiconductor fin.
Regarding Claim 9, Kwon, Masanabu and Wong teach the FinFET according to claim 8, wherein the metal layer comprises tungsten (See above).
Regarding Claim 10, Kwon, Masanabu and Wong teach the FinFET according to claim 8, wherein the gate structure further comprises:
a high-k layer (Kwon, 130), wherein the high-k layer exhibits a U-shape in the cross-sectional view to surround the work function layer [0052; and
an interfacial oxide layer (Wong, 31A), but do not explicitly teach that the interfacial oxide layer exhibits a U-shape in the cross-sectional view to surround the high-k layer.
However, the configuration of a claim element is a matter of choice which a person of ordinary skill in the art would have found obvious absent persuasive evidence that the particular configuration of the claimed element was significant (MPEP 2144.04(IV)(B)). In this case, an interfacial oxide is provided for greater adhesion between a channel and a gate dielectric, and the interfacial oxide of Wong would perform identically to the claimed configuration, as the interfacial oxide would serve no further purpose along the surfaces of the ILD.
Regarding Claim 11, Kwon, Masanabu and Wong teach the FinFET according to claim 8, wherein the barrier layer has an inner sidewall and an outer sidewall opposite to the inner sidewall, the inner sidewall of the barrier layer is in physical contact with the metal layer (see Fig. 1 of Kwon), and the outer sidewall of the barrier layer is in physical contact with the work function layer (in the combination of Kwon and Wong, this would be the natural result as the work function layer 37L is directly outside and in contact with the barrier 38L of Wong).
Regarding Claim 12, Kwon, Masanabu and Wong teach the FinFET according to claim 8, wherein the barrier layer comprises:
a first TiN 141layer;
a second TiN layer 142 over the first TiN layer; and
a trapping layer 143 sandwiched between the first TiN layer and the second TiN layer, wherein the trapping layer comprises silicon oxide, silicon nitride (teaching and combination of Masanbu), aluminum oxide, aluminum nitride, or a combination thereof.
Regarding Claim 13, Kwon, Masanabu and Wong teach the FinFET according to claim 12, wherein the trapping layer further comprises silicon tetrafluoride (SiF4) (natural result of fluorine radicals and SiN layer of Masanbu) or aluminum fluoride (AlF3).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/EVREN SEVEN/ Primary Examiner, Art Unit 2812