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 .
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 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.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 15-20 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Regarding claim 15, there is insufficient antecedent basis for the limitation “the patterned second hardmask layer”. The examiner suggests that the phrase “transferring a pattern of the spacers and the bottom spacer to the first hardmask layer”, which precedes the limitation “the patterned second hardmask layer”, should be corrected to be “transferring a pattern of the spacers and the bottom spacer to the [[first]]second hardmask layer”. This correction provides the required antecedent basis for the limitation “the patterned second hardmask layer”, and has support from the original drawings (Figs. 11-15).
Regarding claims 16-20, they are indefinite due to their dependency on claim 15.
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 1-2 and 4 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Joseph et al. (US10304744).
Regarding claim 1, Joseph discloses a method for processing a substrate (abstract), the method comprising: forming a first hardmask layer over a target layer and a second hardmask layer over the first hardmask layer (substrate 218 reads on a target layer, lines 37-41, column 9 and Fig. 1; mask layer 210 comprising silicon nitride reads on a first hardmask layer, lines 4-6, column 7 and Fig. 1; mask layer 208 comprising silicon oxide reads on a second hardmask layer, lines 14-17, column 7 and Fig. 1); patterning the second hardmask layer (lines 62-67, column 7; and Fig. 3); forming a tone inversion mask between portions of the patterned second hardmask layer (lines 6-12, column 9; and Fig. 5); removing the patterned second hardmask layer (lines 63-66, column 8; and Fig. 6); patterning the first hardmask layer using the tone inversion mask as an etching mask (lines 16-17, column 9; and Fig. 7); and etching the target layer using the patterned first hardmask layer as another etching mask (lines 16-19, column 9; and Fig. 7).
Regarding claim 2, Joseph discloses wherein the target layer comprises a metal (a metallization layer, lines 37-41, column 9).
Regarding claim 4, Joseph discloses wherein the tone inversion mask comprises titanium oxide (lines 24-29, column 8; lines 18-20, column 10).
Claims 8-9 and 12-13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim et al. (US20170154809).
Regarding claim 8, Kim discloses a method for processing a substrate (abstract), the method comprising: forming a mandrel over a target layer (mandrel 110, target layer 320/310, Fig. 2); forming a first cut mandrel and a second cut mandrel from the mandrel with a mandrel cut process (paragraphs 0031-0032; and annotated Fig. 2 below); forming a spacer layer over the first cut mandrel and the second cut mandrel, the spacer layer filling a cut between the first cut mandrel and the second cut mandrel (paragraph 0034 and Fig. 4); etching the spacer layer, wherein remaining portions of the spacer layer form spacers (paragraph 0036 and Fig. 5); exposing a first hardmask layer by removing the first cut mandrel and the second cut mandrel, the first hardmask layer being over the target layer (hardmask layer 330 reads on a first hardmask layer, paragraph 0040 and Fig. 7); transferring a first pattern of the spacers to the first hardmask layer (paragraph 0042 and Fig. 9); forming a tone inversion mask between portions of the patterned first hardmask layer (paragraph 0046 and Figs. 11-14); and transferring a second pattern of the tone inversion mask to the target layer with a subtractive etching process, wherein a tone of the second pattern is the reverse of a tone of the first pattern (paragraph 0058 and Fig. 23).
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Regarding claim 9, Kim discloses wherein the portion of the spacer layer between the first cut mandrel and the second cut mandrel comprises a seam (Fig. 4).
Regarding claim 12, Kim discloses wherein the mandrel cut process comprises: forming a patterned resist over the mandrel, wherein a trench through the patterned resist exposes a portion of the mandrel; and forming a cut through the mandrel with an etching process using the patterned resist as an etch mask (paragraph 0023 and Fig. 2).
Regarding claim 13, Kim discloses wherein forming the tone inversion mask comprises: forming a tone inversion coat over and between portions of the patterned first hardmask layer; and removing a top portion of the tone inversion coat (Figs. 11-12).
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 of this title, 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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Joseph et al. (US10304744) as applied to claim 2 above, in view of Xiao (Introduction to Semiconductor Manufacturing Technology, SPIE Press, 2012, pages 573-575).
Regarding claim 3, Joseph is silent about after etching the target layer, filling gaps formed through the target layer with a filling layer, the filling layer comprising a dielectric material. However, Joseph discloses that the etching he target layer results in formation of metallization in BEOL stack of one or more layers of metallization (lines 16-41, column 9). In addition, Xiao teaches filling gaps of metallization lines with a filling layer, the filling layer comprising a dielectric material (ILD, interlayer dielectric) after formation of aluminum lines (1st picture in Fig. 13.28). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to fill gaps formed through the target layer with a filling layer, the filling layer comprising a dielectric material as taught by Xiao in the method of Joseph, in order to complete the formation of BEOL stack of one or more layers of metallization, with a reasonable expectation of success. It has been held that combining prior art elements according to known methods to yield predictable results is obvious. See MPEP 2143 I.(A).
Claims 5-7 are rejected under 35 U.S.C. 103 as being unpatentable over Joseph et al. (US10304744) as applied to claim 1 above, in view of Shinn et al. (“Chemical-Mechanical Polishing”, in Handbook of Semiconductor Manufacturing Technology 2nd edition, CRC Press, year 2007, page 17-43).
Regarding claim 5, Joseph is silent about wherein the second hardmask layer comprises a stop layer over the mask layer, the stop layer comprising a different material from the mask layer. However, Joseph discloses that the second hardmask comprises silicon oxide and is subjected to a CMP step (lines 14-17, column 7; and lines 52-60, column 8). In addition, Shinn teaches that a polish stop layer, such as silicon nitride, is commonly used to protect underlying region during a CMP process, which can be removed using a wet chemical etch (1st and 3rd paragraphs on page 17-43). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to deposit a stop layer over the mask layer, the stop layer comprising a different material (silicon nitride) from the mask layer (silicon oxide) as taught by Shinn in the method of Joseph, in order to protect silicon oxide during the CMP process, with a reasonable expectation of success. It has been held that combining prior art elements according to known methods to yield predictable results is obvious. See MPEP 2143 I.(A).
Regarding claim 6, Shinn discloses wherein the stop layer comprises silicon nitride (1st paragraph on page 17-43).
Regarding claim 7, Joseph in view of Shinn discloses wherein forming the tone inversion mask comprises: forming a tone inversion coat over and between portions of the patterned second hardmask layer; and removing a top portion of the tone inversion coat with a chemical mechanical polish, wherein the stop layer stops the chemical mechanical polish (Joseph lines 52-62, column 8; Shinn, 1st and 3rd paragraphs on page 17-43).
Claims 10-11 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US20170154809) as applied to claim 8 above, in view of O’Toole et al. (US20200111668).
Regarding claim 10, Kim discloses wherein the mandrel comprises a silicon material (paragraph 0032). Kim is silent about the silicon material being amorphous silicon. However, O’Toole teaches that a silicon material used as a mandrel may be composed of amorphous silicon (paragraph 0022). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to use a known silicon material such as amorphous silicon as taught by O’Toole as the mandrel material in the method of Kim, with a reasonable expectation of success. It has been held that combining prior art elements according to known methods to yield predictable results is obvious. See MPEP 2143 I.(A).
Regarding claim 11, Kim is silent about wherein the spacer layer comprises titanium oxide or titanium nitride. However, O’Toole teaches that a spacer material on a mandrel comprising a silicon material may be composed of titanium oxide (paragraphs 0022-0023). Therefore, it would have been obvious to one of ordinary skill, in the art before the effective filing date of the claimed invention, to use a known spacer material such as titanium oxide as taught by O’Toole as the spacer material in the method of Kim, with a reasonable expectation of success. It has been held that combining prior art elements according to known methods to yield predictable results is obvious. See MPEP 2143 I.(A).
Allowable Subject Matter
Claim 14 is 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 a statement of reasons for the indication of allowable subject matter:
Regarding claim 14, the cited prior art of record, taken either alone or in combination, fails to disclose or render obvious a method wherein portions of the spacers remain over the patterned first hardmask layer after forming the tone inversion coat, in the context of the instant claim. The closest cited prior art of Kim discloses no spacers remain over the patterned first hardmask layer after forming the tone inversion coat (Fig. 11).
Claims 15-20 would be allowable if rewritten or amended to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office Action.
The following is an examiner’s statement of reasons for allowance:
Regarding claim 15, the closest cited prior art of Kim discloses a method for processing a substrate (abstract), the method comprising: forming a first hardmask layer over a conductive layer and a second hardmask layer over the first hardmask layer (layer 320 reads on a first hardmask layer; layer 310 reads on a conductive layer; layer 330 reads on a second hardmask, Fig. 2); forming a first mandrel and a second mandrel over the second hardmask layer (paragraphs 0031-0032; and Fig. 2); forming a spacer layer over the first mandrel and the second mandrel; forming a non-mandrel block between the first mandrel and the second mandrel (paragraph 0034 and Fig. 4); exposing the second hardmask layer by removing the first mandrel and the second mandrel (paragraph 0040 and Fig. 7); transferring a pattern of the spacers and the bottom spacer to the second hardmask layer (paragraph 0042 and Fig. 9); forming a tone inversion mask between portions of the patterned second hardmask layer (paragraph 0046 and Figs. 11-14); removing the patterned second hardmask layer (Fig. 21); patterning the first hardmask layer using the tone inversion mask as an etching mask (Fig. 23); and performing a subtractive etch on the conductive layer using the patterned first hardmask layer as another etching mask (Fig. 23). However, Kim fails to discloses forming a non-mandrel block between the first mandrel and the second mandrel; and performing an anisotropic etching technique on the spacer layer, wherein a first remaining portion of the spacer layer form spacers around sidewalls of the first mandrel and the second mandrel, and wherein a second remaining portion of the spacer layer under the non-mandrel block forms a bottom spacer; exposing the second hardmask layer by removing the first mandrel and the second mandrel. None of the cited prior art of record, taken either alone or in combination, discloses or renders obvious a method comprising the missing processing steps in in the context of the instant claim.
Regarding claims 16-20, they are dependent on claim 15.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JIONG-PING LU whose telephone number is (571) 270-1135. The examiner can normally be reached on M-F: 9:00am – 5:00pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua L Allen, can be reached at telephone number (571)270-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JIONG-PING LU/
Primary Examiner, Art Unit 1713