DETAILED ACTION
This office action is in response to the election filed 10/20/2025.
Currently, claims 1, 3-11 and 13-19 are pending.
Election/Restrictions
Applicant’s election without traverse of Species I is acknowledged.
Drawings
The drawings were received on 5/20/2025. These drawings are acceptable.
Specification
The amendment to the specification was received on 5/20/2025. While the amendment addresses some of the previous issues, the specification is objected to because the description of FIG. 5 and 6 in para. [0012] is not accurate. The amended para. [0012] reads “FIG. 5 and FIG. 6 are a schematic enlarged view of a part X in the embodiment shown in FIG. 4”. FIG. 5 and 6 show different mutually exclusive embodiments, and thus cannot be a same view of a same part shown in FIG. 4.
Claim Objections
Claims 1 and 11 are objected to because of the following informalities: The word “a” is presumably missing preceding “respective one” in line 9 of claim 1 and line 8 of claim 11, while “are” should be “is” in the last line of each claim. Appropriate correction is required.
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 1, 3-6, 8 and 10 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
The claims use the term “respective one of the plurality of bit lines structures” in independent claims 1 and 11, as well as some dependent claims. It is not preceded by a qualifier such as “a” or “the”, and thus there is an issue of antecedent basis, as it is not clear whether these limitations refer to the same thing. Even so, the term “respective” does not appear to fit the context of the claim. For example, there is one (“an”) inclined face claimed in lines 13-14 of claim 1, yet the one face is described as facing respective one of the plurality of bit line structures. It is not clear what the “respective” relationship would be.
Pertaining to claim 4, “each of the plurality of air gaps is formed between each of the bit line structures” does not make sense, particularly in the context of the disclosure. For example, there are six air gaps 720 shown in FIG. 4. It cannot be said that each of those six is formed between each of the bit lines. Furthermore, claim 4 states that “the inclined face is at least partially exposed to the each of the plurality of air gaps. However, there is not a single inclined face that is exposed to all of the air gaps. Rather, that is disclosed in a one-to-one relationship. Claim 14 recites these same limitations.
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)(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.
Claims 1, 5-6, 11 and 15 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Ahn et al. (US 11,908,797).
Pertaining to claim 1, Ahn shows, with reference to FIG. 7G-Q and 3, a manufacturing method of a semiconductor structure, comprising:
providing a substrate (110);
forming a plurality of bit line structures (BL with cap 136 and liner 142) distributed at intervals on the substrate, wherein each of the bit line structures comprises a conductive structure (130 and/or 132), a conductive barrier block (134) and an insulative structure (136/180) which are stacked sequentially, and a width of the conductive barrier block is less than a width of the conductive structure (FIG. 7F);
forming a plurality of air gaps (AS), each of the plurality of air gaps in contact with a side wall of a respective one of the plurality of bit line structures; and
forming a conductive plug comprising a first conductive part (150/172) and a second conductive part (174/176) on the substrate between adjacent ones of the plurality of bit line structures, wherein the second conductive part is above the first conductive part,
wherein a bottom of the second conductive part has an inclined face facing a respective one of the plurality of bit line structures (inclined at 90 degrees), and a top face of the second conductive part is flush with a top face of the insulative structure (top surfaces of 176 and 180 are flush).
Pertaining to claim 11, Ahn shows, with reference to FIG. 2A and 3, a semiconductor structure, comprising:
a substrate (110);
a plurality of bit line structures (BL with cap 136 and liner 142) distributed at intervals on the substrate, wherein each of the bit line structures comprises a conductive structure (130 and/or 132), a conductive barrier block (134) and an insulative structure (136/180) which are stacked sequentially, and a width of the conductive barrier block is less than a width of the conductive structure (FIG. 2A and 3);
a plurality of air gaps (AS), each of the plurality of air gaps in contact with a side wall of a respective one of the plurality of bit line structures (FIG. 3); and
a conductive plug located on the substrate between adjacent bit line structures, wherein the conductive plug comprises a first conductive part (150/172) and a second conductive part (174/176) located above the first conductive part,
wherein a bottom of the second conductive part has an inclined face facing a respective one of the plurality of bit line structures (inclined at 90 degrees), and a top face of the second conductive part is flush with a top face of the insulative structure (top surfaces of 176 and 180 are flush).
Pertaining to claims 5 and 15, Ahn shows two inclined faces are provided and are respectively located on two sides of the bottom of the second conductive part facing the adjacent bit line structures (FIG. 2A).
Pertaining to claims 6 and 16, Ahn shows a perpendicular distance between a vertex angle of the conductive barrier block (e.g. an outer vertex at the bottom) and the inclined face is greater than a perpendicular distance between a vertex angle of the conductive structure (e.g. an inner vertex at the top) and the inclined face (the vertices are on a same horizontal plane, but the vertex of the conductive structure is closer to the inclined face in an x-direction).
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, 4, 11, 13 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Ahn in view of Kim et al. (US 11,805,639). Note that the interpretation of Ahn is the same as in the 35 U.S.C. 102 rejections above except for the inclined face.
Pertaining to claim 1, Ahn shows, with reference to FIG. 7G-Q and 3, a manufacturing method of a semiconductor structure, comprising:
providing a substrate (110);
forming a plurality of bit line structures (BL with cap 136 and liner 142) distributed at intervals on the substrate, wherein each of the bit line structures comprises a conductive structure (130 and/or 132), a conductive barrier block (134) and an insulative structure (136/180) which are stacked sequentially, and a width of the conductive barrier block is less than a width of the conductive structure (FIG. 7F);
forming a plurality of air gaps (AS), each of the plurality of air gaps in contact with a side wall of a respective one of the plurality of bit line structures; and
forming a conductive plug comprising a first conductive part (150/172) and a second conductive part (174/176) on the substrate between adjacent ones of the plurality of bit line structures, wherein the second conductive part is above the first conductive part,
wherein a top face of the second conductive part is flush with a top face of the insulative structure (top surfaces of 176 and 180 are flush).
Pertaining to claim 11, Ahn shows, with reference to FIG. 2A and 3, a semiconductor structure, comprising:
a substrate (110);
a plurality of bit line structures (BL with cap 136 and liner 142) distributed at intervals on the substrate, wherein each of the bit line structures comprises a conductive structure (130 and/or 132), a conductive barrier block (134) and an insulative structure (136/180) which are stacked sequentially, and a width of the conductive barrier block is less than a width of the conductive structure (FIG. 2A and 3);
a plurality of air gaps (AS), each of the plurality of air gaps in contact with a side wall of a respective one of the plurality of bit line structures (FIG. 3); and
a conductive plug located on the substrate between adjacent bit line structures, wherein the conductive plug comprises a first conductive part (150/172) and a second conductive part (174/176) located above the first conductive part,
wherein a top face of the second conductive part is flush with a top face of the insulative structure (top surfaces of 176 and 180 are flush).
As it pertains to claims 4 and 14, Ahn shows the air gap is formed between each of the bit line structures and the conductive plug (FIG. 3, 7Q).
Ahn fails to show, pertaining to claims 1, 3, 11 and 13, that the bottom of the second conductive part has an inclined face, a bottom face, and a vertical face between the bottom face and the inclined face, wherein the bottom face is in contact with a top face of the first conductive part, the vertical face has one end connected with the bottom face and one end away from the bottom face connected with the inclined face. As it pertains to claims 4 and 14, Ahn fails to show the inclined face is at least partially exposed to the air gap.
However, Kim teaches in FIG. 2A and 3 that, for a similar arrangement in which a conductive plug comprising a first conductive part (160/165) and a second conductive part (172/174/176/178) is formed between adjacent bit line structures (BLS), the bottom of the second conductive part (top is interpreted to be portion below and having the same lateral dimension as lower electrode 192, while the remaining portion is interpreted to be the bottom portion) has an inclined face (angled portion of 176), a bottom face (172 in contact with 165), and a vertical face (portion of 172 in contact with 176) between the bottom face and the inclined face, wherein the bottom face is in contact with a top face of the first conductive part (top of 165), the vertical face has one end connected with the bottom face and one end away from the bottom face connected with the inclined face (shown in FIG. 2A and 3). Furthermore, Kim teaches the inclined face is at least partially exposed to the air gap 156.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the conductive plug of Ahn in accordance with the teaching of Kim, with the motivation that such a structure has a reduced contact resistance and sufficient electrical isolation even in the case of misalignment (col. 8, line 63 – col. 9, line 14). Furthermore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to substitute the contact plug structure of Ahn for that taught by Kim, as the court has held that the simple substitution of one known element for another to obtain predictable results is prima facie obvious. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007).
Claims 8 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Ahn.
Ahn shows the method and structure of claims 6 and 16, wherein the width of the conductive barrier block is less than the width of the conductive structure (col. 4, lines 21-26). Although Ahn does not explicitly show the exact relative proportioes, this would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233 (1955).
Claims 10 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Ahn in view of Buckalew et al. (US 10,211,052).
Ahn shows a material of the conductive barrier block comprises one of a metal nitride, a metal silicide, or a metal silicide nitride (col. 4, lines 60-64). For example, the material may be WN. It is not explicitly clear whether Ahn uses WN to disclose tungsten nitride generally, or if it is intended to represent stoichiometric tungsten nitride.
Although Ahn does not explicitly show the material being metal-rich, Buckalew teaches in col. 5, lines 21-22 that tungsten nitride may be provided as one of W2N, WN, and WN2.
In the case that Ahn discloses tungsten nitride generally, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to try W2N, as taught by Buckalew, for the tungsten nitride material of Ahn, as the court has held that choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success is prima facie obvious. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007).
In the case that Ahn discloses stoichiometric tungsten nitride, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to substitute the WN of Ahn for the W2N taught by Buckalew, as the court has held that the simple substitution of one known element for another to obtain predictable results is prima facie obvious. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007).
Response to Arguments
Applicant's arguments filed 5/20/2025 have been fully considered but they are not persuasive.
Applicant argues that Ahn shows the top face of conductive part 174 is over the top face of cap 136, and thus Ahn fails to show “wherein a bottom of the second conductive part has an inclined face facing respective one of the plurality of bit line structures, and a top face of the second conductive part are flush with a top face of the insulative structure”.
In response, 136 alone is not interpreted to be the insulative structure, but rather 136 in combination with 180 make up the insulative structure. The top face of this structure is the top face of 180, which is flush with the top face of 176, which is interpreted to be a part of the second conductive part. Thus, Ahn indeed shows a bottom of the second conductive part has an inclined face facing respective one of the plurality of bit line structures, and a top face of the second conductive part is flush with a top face of the insulative structure.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL M LUKE whose telephone number is (571)270-1569. The examiner can normally be reached Monday-Friday, 9am-5pm, EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, William Kraig can be reached at (571) 272-8660. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DANIEL LUKE/Primary Examiner, Art Unit 2896
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