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 .
Election/Restrictions
Applicant’s election without traverse of Invention I (claims 1-15, 21-25) in the reply filed on October 31, 2025 is acknowledged.
Claim Rejections - 35 USC § 102
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.
Claims 21 and 24 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Lee et al (US Publication No. 2021/0398861).
Regarding claim 21, Lee discloses a method for forming a semiconductor structure, comprising: forming a first active region Fig 5B, 300-72 and a second active region Fig 5B, 400-72 over a substrate; forming a first n-type epitaxial material on a source/drain region of the first active region and a second n-type epitaxial material on a source/drain region of the second active region ¶0057 Fig 14; forming an n-type work function layer Fig 11, 98 over a channel region of the first active region and a channel region of the second active region; forming a protection layer Fig 11, 100 on the n-type work function layer Fig 11, 98; removing a first portion of the protection layer over the first active region while remaining a second portion of the protection layer over the second active region Fig 11; and depositing a metal fill layer over a first portion of the n-type work function layer over the first active region and the second portion of the protection layer Fig 13.
Regarding claim 24, Lee discloses, before forming the n-type work function layer: forming a first interfacial layer and a second interfacial layer on the channel regions of the first active region and the second active region, respectively; and forming a first high-k gate dielectric layer and a second high-k gate dielectric layer on the first interfacial layer and the second interfacial layer, respectively Fig 7 ¶0033-0034.
Claim Rejections - 35 USC § 103
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 1-3 are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al (US Publication No. 2021/0398861) in view of Zhu et al (US Publication No. 2015/0303117) and Wu et al (US Publication No. 2018/0190546).
Regarding claim 1, Lee discloses a method for forming a semiconductor structure, comprising: forming a first active region Fig 9, 400 and a second active region Fig 9, 500 over a first n-type device region and a first p-type device region of a substrate ¶0017-0018, respectively; forming a first work function layer Fig 9, 98 and a second work function layer Fig 9, 100 along the first active region and the second active region, respectively; forming a material Fig 9, 104 along the first work function layer and the second work function layer Fig 9; removing a first portion of the material along the second work function layer Fig 9, thereby leaving a second portion of the material as a first protection layer over the first work function layer Fig 9; and diffusing a dopant into the first work function layer to form a work function layer while the first protection layer blocks the dopant from diffusing into the first work function layer ¶0044-0046 Fig 9-11.Lee discloses all the limitations but silent on the semiconductor material that acts as a mask. Whereas Zhu discloses forming a semiconductor material as a first protection layer over the device ¶0021. Lee and Zhu are analogous art because they are directed to semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the Lee and incorporate the a semiconductor mask of Zhu as an alternative material as a protection layer during implantation and since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of design choice. In re Leshin, 125 USPQ 416 (1960). Lee discloses all the limitations but silent on the type of first work function material formed in the first and a second active region. Whereas Wu discloses a method for forming a semiconductor structure, comprising: forming a first active region Fig 7, 103 and a second active region Fig 7, 101 over a first n-type device region and a first p-type device region of a substrate ¶0018, respectively; forming a first n-type work function layer Fig 7, 501 ¶0020 and a first p-type work function layer Fig 7, 701 ¶0021 along the first active region and the second active region, respectively. Lee and Wu are analogous art because they are directed to semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the Lee and incorporate the specific material choices for the work function layer since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of design choice. In re Leshin, 125 USPQ 416 (1960).
Regarding claim 2, Zhu discloses wherein the semiconductor material is silicon¶0021.
Regarding claim 3, Lee in view of Zhu discloses wherein the thickness of the first n-type work function layer is thicker than a thickness of the material (mask layer) ¶0035 and 0038.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Lee et al (US Publication No. 2021/0398861) in view of Zhu et al (US Publication No. 2015/0303117) and Wu et al (US Publication No. 2018/0190546) and in further view of Chiu et al (US Publication No. 2018/0174922).
Regarding claim 4, Lee discloses all the limitations but silent on the dopant. Whereas Chiu discloses wherein the dopant includes oxygen, fluorine, or nitrogen ¶0056-0057 Claim 2-3. Lee and Chiu are analogous art because they are directed to semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify Lee and incorporate the specific doping material to adjust the desired threshold voltage ¶0055 and since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of design choice. In re Leshin, 125 USPQ 416 (1960).
Claims 11-12, 22 are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al (US Publication No. 2021/0398861) in view of Colombo et al (US Publication No. 2009/0053883).
Regarding claim 11, Lee discloses a method for forming a semiconductor structure, comprising: forming a first active region Fig 5B, 500-72 and a second active region Fig 5B, 400-72 over a substrate Fig 5B, 70; forming a dummy gate structure Fig 5B, 78 across the first active region and the second active region Fig 5B; removing the dummy gate structure to form a trench ¶0032;forming a first work function layer Fig 7, 98 on the first active region in the trench; forming a second work function layer Fig 9, 100 on the second active region in the trench; forming a protection layer Fig 9, 104 on the first work function layer Fig 9, 98 in the trench while exposing the second work function layer Fig 9, 100; and forming a metal fill layer Fig 13, 118 on the protection layer and the second work function layer to overfill the trench Fig 13. Lee discloses all the limitations but silent on the dopant diffusion. Whereas Colombo discloses wherein a dopant diffuses through the metal fill layer and into the second work function layer during formation of the metal fill layer Fig 12-13 ¶0051-0052. Lee and Colombo are analogous art because they are directed to semiconductor devices having metal gates and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the Lee and incorporate the teachings of Colombo as alternative method to diffuse dopants to the metal layers.
Regarding claim 12, Colombo discloses wherein the protection layer 395/405 blocks the dopant from diffusing into the first work function layer Fig 12-13. Lee and Colombo are analogous art because they are directed to semiconductor devices having metal gates and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the Lee and incorporate the teachings of Colombo to adjust and control the amount of dopants dispensed into the device.
Regarding claim 22, Colombo discloses doping a dopant into the first portion of the n-type work function layer while the second portion of the protection layer blocks the dopant from diffusing into a second portion of the n-type work function layer over the second active region ¶0051-0052 Fig 12-13.
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Lee et al (US Publication No. 2021/0398861) in view of Guo et al (US Publication No. 2023/0026989).
Regarding claim 25, Lee discloses all the limitations but silent on the type of channel region. Whereas Gou wherein each of the first active region and the second active region includes alternating first semiconductor layers and second semiconductor layers, and the method for forming the semiconductor structure further comprises: removing the first semiconductor layers of the first active region and the first semiconductor layers of the second active region, wherein the n-type work function layer wraps around the second semiconductor layers of the first active region and the second semiconductor layers of the second active region¶0106 Fig 25, 101A/101B (102). Lee and Gou are analogous art because they are directed to semiconductor devices having metal gates and one of ordinary skill in the art would have had a reasonable expectation of success to modify Lee because they are from the same field of endeavor. Therefore, it would have been obvious to one having ordinary skill of the art before the effective filing date of the claimed invention to modify the Lee and incorporate the teachings of Gou as alternative active region known in the art to improve device performance.
Allowable Subject Matter
Claims 5-10, 13-15, 23 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Conclusion
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/CHRISTINE A ENAD/Primary Examiner, Art Unit 2811