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 .
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 .
DETAILED ACTION
Priority
Acknowledgment is made of applicant's claim for foreign benefit based on JP2021-150249 filed on 09/15/2021.
Election/ Restrictions
Applicant's election of group II without traverse: claims 1-26, in the “Response to Election / Restriction Filed - 12/21/2025”, withdrawal of non-elected claim(s) 27-33 is/are acknowledged. This office action considers claims 1-33, in “Claims - 08/25/2023”, pending for prosecution, of which claim(s) 27-33 is/are withdrawn.
Claim Rejections - 35 USC § 102
The following is a quotation of 35 U.S.C. 102(a)(2):
(a) NOVELTY; PRIOR ART.—A person shall be entitled to a patent unless—
(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.
Notes: when present, semicolon separated fields within the parenthesis (; ;) represent, for example, as (30A; Fig 2B; [0128]) = (element 30A; Figure No. 2B; Paragraph No. [0128]). For brevity, the texts “Element”, “Figure No.” and “Paragraph No.” shall be excluded, though; additional clarification notes may be added within each field. The number of fields may be fewer or more than three indicated above. These conventions are used throughout this document.
Claims 1-5, 7-9, 13-15, 17, 22-25 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Tamura et al. (US 20220013635 A1 – hereinafter Tamura).
Regarding Claim 1, Tamura teaches a semiconductor device (see the entire document; Figs. 1-2; specifically, [0059]-[0161], and as cited below), comprising:
a drift region (18 – Fig. 1) of a first conductivity type (n-type – [0061] which is provided in a semiconductor substrate (10 – [0059]);
a buffer region (20) of the first conductivity type (n-type – [0061]) which is provided in a back surface (closer to lower surface 23) side of the semiconductor substrate (10) relative to the drift region (18) and has a first peak (25 of Fig. 2) of a doping concentration (Fig. 2); and
a first lattice defect region which is provided in a front surface side of the semiconductor substrate relative to the first peak in a depth direction of the semiconductor substrate and has a recombination center (the buffer region 20 is formed by implanting hydrogen ions from the lower surface 23, and lattice defects are formed in a region through which the hydrogen ions implanted from the lower surface 23 have passed – [0068]), wherein
the buffer region (20) has a hydrogen peak which is provided in the front surface side of the semiconductor substrate relative to the first lattice defect region and corresponds to a hydrogen chemical concentration peak of a hydrogen chemical concentration distribution (the buffer region 20 is formed by implanting hydrogen ions from the lower surface 23, and lattice defects are formed in a region through which the hydrogen ions implanted from the lower surface 23 have passed; the hydrogen chemical concentration distribution in the buffer region 20 has hydrogen concentration peaks 125-1, 125-2, 125-3, and 125-4 in order from the lower surface 23 side at depth positions where hydrogen ions are implanted – Fig. 2 and [0068]-[0069]),
an integrated concentration obtained by integrating the doping concentration in a direction from an upper end of the drift region to the hydrogen peak in the depth direction of the semiconductor substrate is equal to or larger than a critical integrated concentration (the depth positions from the lower surface 23 of hydrogen concentration peaks 125-1, 125-2, 125-3, and 125-4 coincide with the depth positions from the lower surface 23 of doping concentration peaks 25-1, 25-2, 25-3, and 25-4, respectively – Fig. 2), and
an integrated concentration obtained by integrating the doping concentration in a direction from the upper end of the drift region to an upper end of the first lattice defect region in the depth direction of the semiconductor substrate is equal to or larger than the critical integrated concentration (when the depth position of the lower end of a trench portion such as a gate trench portion 40 is defined as Zt, the integrated concentration of the doping concentration of the semiconductor substrate 10 from the position Zt toward the lower surface 23 of the semiconductor substrate 10 is defined as the integrated concentration, and the depth position where the integrated concentration is larger than the critical integrated concentration nc of the semiconductor substrate 10 is defined as the critical position Znc, the critical position Znc overlaps with the hydrogen concentration peak 125-2 and the doping concentration peak 25-2 – see Fig. 17, [0158]-[0161]).
Regarding Claim 2, Tamura teaches the semiconductor device according to claim 1, wherein the first peak is a peak closest to the back surface of the semiconductor substrate out of a plurality of peaks included in the buffer region (see region 20 peak in Fig. 2).
Regarding Claim 3, Tamura teaches the semiconductor device according to claim 1, wherein the hydrogen peak includes a second peak second closest to the back surface of the semiconductor substrate after the first peak out of a plurality of peaks included in the buffer region (peak 125-2 in Fig. 2).
Regarding Claim 4, Tamura teaches the semiconductor device according to claim 3, wherein the first lattice defect region is provided between the first peak and the second peak in the depth direction of the semiconductor substrate.
Regarding Claim 5, Tamura teaches the semiconductor device according to claim 3, wherein a recombination center density in the back surface side of the semiconductor substrate relative to the hydrogen peak is higher than a recombination center density in the drift region in a side adjacent to the hydrogen peak (lattice defects are formed in the region through which the hydrogen ions implanted from the lower surface 23 have passed, and therefore in the depth direction of the semiconductor substrate 10, the region between the doping concentration peak 25-1 and the hydrogen concentration peak 125-2 corresponds to the "first lattice defect region having a recombination center" – [0069]).
Regarding Claim 7, Tamura teaches the semiconductor device according to claim 1, wherein a width of the first lattice defect region in the depth direction of the semiconductor substrate is 25% or more of an interval between the first peak and the hydrogen peak (Fig. 2 reaches the limitations of claim 7).
Regarding Claim 8, Tamura teaches the semiconductor device according to claim 1, wherein a width of the first lattice defect region in the depth direction of the semiconductor substrate is larger than a width of the first peak in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 8).
Regarding Claim 9, Tamura teaches the semiconductor device according to claim 1, wherein a width of the first lattice defect region in the depth direction of the semiconductor substrate is larger than a width of the hydrogen peak in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 8).
Regarding Claim 13, Tamura teaches the semiconductor device according to claim 1, wherein the buffer region has the first peak and a plurality of hydrogen peaks formed by hydrogen ion implantation (Fig. 2 reaches the limitations of claim 13).
Regarding Claim 14, Tamura teaches the semiconductor device according to claim 13, wherein the first lattice defect region is provided between the plurality of hydrogen peaks in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 14).
Regarding Claim 15, Tamura teaches the semiconductor device according to claim 13, comprising: a second lattice defect region provided between the plurality of hydrogen peaks in the front surface side of the semiconductor substrate relative to the first lattice defect region in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 15).
Regarding Claim 17, Tamura teaches the semiconductor device according to claim 1, comprising: a first lifetime control region provided in the front surface side of the semiconductor substrate relative to the first peak in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 15).
Regarding Claim 22, Tamura teaches the semiconductor device according to claim 17, wherein a peak position of the first lifetime control region is between the hydrogen peak and the drift region in the depth direction of the semiconductor substrate (Fig. 2 reaches the limitations of claim 15).
Regarding Claim 23, Tamura teaches the semiconductor device according to claim 1, wherein a dopant of the first peak is phosphorus ([0129]).
Regarding Claim 24, Tamura teaches the semiconductor device according to claim 1, wherein a dopant of the first peak is hydrogen ([0069] and Fig. 2).
Regarding Claim 25, Tamura teaches the semiconductor device according to claim 1, wherein a doping concentration of the first lattice defect region is lower than or equal to a doping concentration of the drift region (Fig. 2 reaches the limitations of claim 15).
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.
Notes: when present, semicolon separated fields within the parenthesis (; ;) represent, for example, as (30A; Fig 2B; [0128]) = (element 30A; Figure No. 2B; Paragraph No. [0128]). For brevity, the texts “Element”, “Figure No.” and “Paragraph No.” shall be excluded, though; additional clarification notes may be added within each field. The number of fields may be fewer or more than three indicated above. These conventions are used throughout this document.
Claims 6, 12, 16, 26 are rejected under 35 U.S.C. 103 as being unpatentable over Tamura.
Regarding Claims 6, 12, 16, 26, Tamura teaches claim 1 from which they depend from. But Tamura does not expressly disclose the specific numeral values added in these claims.
The instant application specification contains no disclosure of either the critical nature of the claimed numerical. Applicant has not disclosed that having these numerical values solves any stated problem or is for any particular purpose. Where patentability is said to be based upon particular chosen dimensions, alignment, positioning, or upon another variable recited in a claim, the applicant must show that the chosen values are critical. (.In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990).). In view of the above, inter alia, the limitation of “wherein a thickness of the barrier layer is less than 10% of a total thickness of the first ILD, the barrier layer, and the second ILD” is not patentable over Tamura.
Allowable Subject Matter
Claims 10-11, 18-21 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.
The following is the Examiner’s Reasons for Allowance:
The prior art fails to disclose and would not have rendered obvious:
Regarding claim 10: The semiconductor device according to claim 1, wherein a width of the first lattice defect region in the depth direction of the semiconductor substrate is larger than a sum of widths of regions other than the first lattice defect region in the buffer region.
Regarding claim 11: The semiconductor device according to claim 1, wherein a minimum value of the hydrogen chemical concentration distribution in the first lattice defect region is smaller than a peak concentration of the doping concentration in the first peak.
Regarding claim 18: The semiconductor device according to claim 17, wherein the first lifetime control region contains helium.
Regarding claim 19: The semiconductor device according to claim 17, wherein a peak position of the first lifetime control region is in the back surface side of the semiconductor substrate relative to the hydrogen peak in the depth direction of the semiconductor substrate.
Regarding claim 20: The semiconductor device according to claim 17, wherein a peak position of the first lifetime control region is between the first lattice defect region and the hydrogen peak in the depth direction of the semiconductor substrate.
Regarding Claim 21: The semiconductor device according to claim 17, wherein a peak position of the first lifetime control region is provided in the back surface side of the semiconductor substrate relative to the first lattice defect region in the depth direction of the semiconductor substrate.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMMAD A. RAHMAN whose telephone number is (571) 270-0168 and email is mohammad.rahman5@uspto.gov. The examiner can normally be reached on Mon-Fri 8:00-5:00 PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Julio J. Maldonado can be reached on (571) 272-1864. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/MOHAMMAD A RAHMAN/
Primary Examiner, Art Unit 2898