DETAILED ACTION
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 .
Specification
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
Claim Objection
Clam 1 recites “a gate structure, form bottom to top, comprising”; it is not clear what this means; it appears “form” should be “from”.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim 1-3, 5, 8-13, 15, and 18-20 rejected under 35 U.S.C. 102(a)(1) and 102(a)(2) as being anticipated by Hempel, US 2012/0315749 A1.
Claim 1: Hempel discloses
a gate structure, form bottom to top, comprising:
a gate insulating layer (314) disposed on a substrate;
a first barrier layer (315a) disposed on the gate insulating layer, wherein the first barrier layer comprises a transition metal nitride (TiN), and a concentration of nitrogen atom of a portion of the first barrier layer adjacent to the gate insulating layer is higher than a concentration of nitrogen atom of a portion of the first barrier layer away from the gate insulating layer (FIGS4a-4c);
and a gate conductive layer (309/316) disposed on the first barrier layer.
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Claim 2: the first barrier layer defines a normal direction, and a concentration of nitrogen atom of the first barrier layer decreases gradually along the normal direction from bottom to top (FIG. 4a).
Claim 3: the first barrier layer comprises a first sub-layer (215a-1) and a second sub-layer (215a-2) from bottom to top, and a concentration of nitrogen atom of the first sub-layer is higher than a concentration of nitrogen atom of the second sub-layer (FIGS. 4a-4d). 215a is formed to have a nitrogen gradient ([0042]), with the closer layer 215a-1 having higher nitrogen content.
Claim 5: the first sub-layer has a first thickness, the second sub-layer has a second thickness, and a ratio of the first thickness to the second thickness ranges from 1/3 to 3: “the first metal gate cap layer 215a-1 may be formed to a thickness that is approximately one-half of the targeted thickness of the first sub-layer 215a.” [0039]. Thus the ratio is approximately 1.
Claim 8: the gate conductive layer comprises a non-metallic conductor (polysilicon, FIG. 3c).
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Claim 9: the gate conductive layer comprises a metallic conductor (316, [0063]).
Claim 10: the gate structure further comprises: a second barrier layer (315b) disposed on the first barrier layer, wherein the second barrier layer has a U-shaped cross section; and a work function metal layer (315c, [0063]) disposed on the second barrier layer, wherein the work function metal layer has a U-shaped cross section.
Claim 11: Hempel discloses
forming a gate structure, comprising:
forming a gate insulating (314) layer on a substrate;
forming a first barrier layer (315a) on the gate insulating layer, wherein the first barrier layer comprises a transition metal nitride (TiN), and a concentration of nitrogen atom of a portion of the first barrier layer adjacent to the gate insulating layer is higher than a concentration of nitrogen atom of a portion of the first barrier layer away from the gate insulating layer (FIGS4a-4c);
and forming a gate conductive layer (309/316) on the first barrier layer.
Claim 12: the first barrier layer defines a normal direction, and a concentration of nitrogen atom of the first barrier layer decreases gradually along the normal direction from bottom to top (FIG. 4a).
Claim 13: forming the first barrier layer comprises: forming a first sub-layer (215a-1) on the gate insulating layer; and forming a second sub-layer (215a-2) on the first sub-layer, wherein a concentration of nitrogen atom of the first sub-layer is higher than a concentration of nitrogen atom of the second sub-layer. 215a is formed to have a nitrogen gradient ([0042]), with the closer layer 215a-1 having higher nitrogen content.
Claim 15: the first sub-layer has a first thickness, the second sub-layer has a second thickness, and a ratio of the first thickness to the second thickness ranges from 1/3 to 3: “the first metal gate cap layer 215a-1 may be formed to a thickness that is approximately one-half of the targeted thickness of the first sub-layer 215a.” [0039]. Thus the ratio is approximately 1.
Claim 18: the gate conductive layer comprises a non-metallic conductor (polysilicon dummy gate 309, [0060], FIG. 3c).
Claim 19: Hempel discloses forming a spacer (310) surrounding the gate structure; removing the non-metallic conductor to form a recess in the spacer; and filling a metallic conductor (316) into the recess ([0062]-[0063], FIG. 3d).
Claim 20: Hempel discloses
forming a second barrier layer (215b/315b) in the recess, wherein the second barrier layer has a U-shaped cross section;
forming a work function metal layer (215c/315c, [0055]) in the recess and on the second barrier layer, wherein the work function metal layer has a U-shaped cross section (FIG. 2m);
and filling the metallic conductor into the recess and on the work function metal layer ([0063]).
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Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 4, 6, 7, 14, 16, and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Hempel.
Claim 4: Hempel does not disclose the resistivity of the sublayers. However, the device of Hempel is substantially similar to the present device in significant (and claimed) respects. “Where, as here, the claimed and prior art products are identical or substantially identical, or are produced by identical or substantially identical processes, the PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of his claimed product. See In re Ludtke, supra. Whether the rejection is based on ‘inherency’ under 35 USC 102, on ‘prima facie obviousness’ under 35 USC 103, jointly or alternatively, the burden of proof is the same, and its fairness is evidenced by the PTO's inability to manufacture products or to obtain and compare prior art products.” In re Best, 562 F.2d 1252, 1254, 195 USPQ 430, 433-434 (CCPA 1977).
Furthermore, The specification contains no disclosure of either the critical nature of the claimed resistivities or any unexpected results arising therefrom. Where patentability is said to be based upon parameters recited in a claim, the Applicant must show that the parameters are critical. In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990).
Claim 14: Hempel does not disclose the flow rate of process gases; however, these would be within ordinary skill in the art to determine. This is a result-effective variable: “the deposition parameters used to perform the deposition process 233c may be adjusted such that the nitrogen content of the second metal gate cap layer 215a-2 is greater than the nitrogen content of the first metal gate cap layer 215a-1” [0042]. Thus those practicing the invention of Hempel will adjust the process parameters such as gas flow rates to achieve the desired outcomes, such as nitrogen gradient.
Claims 6 and 16: Hempel does not disclose that a thickness of the first barrier layer ranges from 20 angstroms to 30 angstroms. However, it would have been within ordinary skill in the art to determine the appropriate thickness based on design considerations such as the design node, the material properties of the barrier layer, etc. Changes in dimension are not typically a source of patentable distinction absent unexpected results. MPEP 2144.04(IV).
Claims 7 and 17 recite forming a composite material layer between the first barrier layer and the gate conductive layer, wherein the composite material layer comprises silicon and a transition metal identical to a transition metal of the transition metal nitride. In forming a replacement gate, polysilicon dummy gate electrode 309 ([0062]) is deposited on TiN layer 315a. Such replacement gate processes are used to allow for annealing before the metal gate is formed. Therefore, during the annealing, it is likely that some trace amount of silicon will react with the titanium nitride at the interface to form such a composite material layer including titanium and silicon.
Claims 7 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Hempel in view of Hou, US 2013/0032900 A1. Hempel does not disclose the claimed composite layer. Hou discloses a composite material layer (140) disposed between the first barrier layer (130) and the gate conductive layer (135), wherein the composite material layer comprises silicon and a transition metal (titanium silicide, [0014]) identical to a transition metal of the transition metal nitride (titanium nitride, [0014]). It would have been obvious to have such a composite layer of TiSi in Hempel in order to prevent diffusion of metal into the barrier layer in order to prevent dielectric breakdown (Hou, abstract).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Yin, CN 118800777 A, which discloses titanium nitride layer 30 with a nitrogen gradient.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER BRADFORD whose telephone number is (571)270-1596. The examiner can normally be reached 10:30-6:30.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jacob Choi can be reached at 469.295.9060. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/PETER BRADFORD/Primary Examiner, Art Unit 2897
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