DETAILED ACTION
This office action is in response to the election filed 11/21/2025.
Currently, claims 1-20 are pending.
Election/Restrictions
Applicant's election with traverse of claims 1-7 is acknowledged. The traversal is on the ground(s) that there is no a serious search/examination burden. Upon examining the application, this argument is found to be persuasive. Thus, the election of species requirement is withdrawn.
Drawings
Figure 1 should be designated by a legend such as --Prior Art-- because only that which is old is illustrated. See MPEP § 608.02(g). Corrected drawings in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. The replacement sheet(s) should be labeled “Replacement Sheet” in the page header (as per 37 CFR 1.84(c)) so as not to obstruct any portion of the drawing figures. If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
The specification is objected to as failing to provide proper antecedent basis for the claimed subject matter. See 37 CFR 1.75(d)(1) and MPEP § 608.01(o). Correction of the following is required: The limitation of claim 7 “determining a first interval of exposing the at least one opening of the substrate to the nitrogen-containing gas and a second interval of exposing the substrate to the nitrogen-containing plasma based on: an interface location of a first and second tier of the multi-tier portion along a length of the at least one opening; a width of the at least one opening at an interface of two adjacent tiers of the multi- tier portion; a width of the at least one opening at a surface of the opening; a ratio between a smallest width along the at least one opening to the largest width along the opening; an aspect ratio of the at least one opening; or combinations thereof” is not disclosed in the specification.
Claim Objections
Claims 3 and 13 are objected to because of the following informalities: The term “seconds” is improperly used following “1” in line 3 of each claim. It should instead be “second” (singular). 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 3-5 and 7-20 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 applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 3 recites the limitation “wherein exposing the at least one opening to a molybdenum-containing gas to remove a desired amount of a tungsten nitride passivation layer from the fill layer comprises …” However, this particular limitation does not have antecedent basis in the claims. Claim 1 does recite “exposing the at least one opening to a molybdenum-containing gas to remove a desired amount of a tungsten nitride passivation layer”, but the language “from the fill layer” is not recited. Claims 4-5 recite the same limitation via dependency.
Claim 7 recites the limitation “exposing the at least one opening of the substrate to the nitrogen-containing gas” in lines 1-2. There are two recitations of such a step in the claims on which claim 7 depends. From claim 1: “exposing the at least one opening of the substrate to a nitrogen-containing gas” (line 8). From claim 6: “exposing the at least one opening of the substrate to the nitrogen-containing gas”. It is not clear which of these is being referenced in claim 7. For purposes of examination, because claim 6 recites the exposure as being either a nitrogen-containing gas or a nitrogen-containing plasma, and claim 7 recites the exposures of the nitrogen-containing gas and the nitrogen-containing plasma as being apparently separate steps, it is presumed that the nitrogen-containing gas recited in claim 7 refers to the nitrogen-containing gas recited in claim 1.
Furthermore, claim 7 recites the limitation “determining a first interval of exposing the at least one opening of the substrate to the nitrogen-containing gas and a second interval of exposing the substrate to the nitrogen-containing plasma based on: an interface location of a first and second tier of the multi-tier portion along a length of the at least one opening; a width of the at least one opening at an interface of two adjacent tiers of the multi- tier portion; a width of the at least one opening at a surface of the opening; a ratio between a smallest width along the at least one opening to the largest width along the opening; an aspect ratio of the at least one opening; or combinations thereof”. However, there is nothing linking the claimed parameters to the intervals. For example, how does the interface location affect the first and second intervals? Would a relatively low location lead to a determination of a longer or shorter first and/or second interval? Without an understanding of the effects, the claim is indefinite.
Claim 8 recites several limitations regarding a fill layer – “a portion of a fill layer” in line 11, “the fill layer” in line 15, and “the fill layer” in line 18. It is not clear what is meant by “fill layer” in the context of the disclosure. The use of the term “portion of a fill layer” implies that the fill layer would be the whole fill layer, i.e. the fill layer at the end of the overall process. It then becomes ambiguous as to whether “the fill layer” recited in line 15 refers to the portion of the fill layer, or the whole of the fill layer. Similarly, it is ambiguous as to whether “the fill layer” recited in line 18 refers to the whole of the fill layer, or to a remaining portion of the fill layer other than the claimed “portion of a fill layer”.
Similarly, as it pertains to claim 11, it is not clear what is being referenced by the limitation “portions of the fill layer”. It is a plural term, so it does not directly reference the singular portion of a fill layer recited in claim 8. Furthermore, it is not clear whether it is a positively recited limitation, i.e. whether or not the portions are actually formed and exist within the process.
Claim 12 recites the limitations “an opening within the upper tier” and “an opening within the lower tier”. Meanwhile, claim 8 on which claim 12 depends recites “at least one opening … wherein the at least one opening comprises a lower portion and an upper portion”. The terms used are similar, but there is not any language linking them together. In other words, are the openings recited in claim 12 the same as the at least one opening recited in claim 8? It is not clear based on the claim language. Furthermore, it is not clear whether “an opening within the upper tier” has any relation to “an opening within the lower tier”. For purposes of examination, it is presumed that the openings recited in claim 12 are parts of the at least one opening recited in claim 8, consistent with the disclosure.
Claim 15 recites the limitation “the nitrogen-containing gas is selected from the group consisting of … a nitrogen-containing plasma”. This appears to be contradictory, as plasma is a state of matter that is different from gas.
Claim 16 recites the limitation “to inhibit growth of portions of the fill layer along the at least one opening” in lines 8-9. Similar to claim 11, it is not clear whether this is a positively recited limitation, i.e. whether or not the portions are actually formed and exist within the process.
Claim 19 recites the limitation “exposing the second fill layer … to the nitrogen-containing gas or the nitrogen-containing plasma to inhibit growth of the second fill layer”. In order for the second fill layer to be exposed, it must first exist. It is unclear then how its growth could be inhibited, as it is already formed.
Allowable Subject Matter
Claims 1-2 and 6 are allowed.
The following is a statement of reasons for the indication of allowable subject matter:
Generally, claim 1 is directed towards a method for filling an opening with a tungsten material. More particularly, the method involves forming a nucleation layer by cyclical deposition of a tungsten-containing gas a reducing agent, exposure to a nitrogen-containing gas to inhibit growth of the nucleation layer at narrow portions within the opening, exposing the opening to the tungsten-containing gas to form a fill layer over the nucleation layer within the opening, and exposing the opening to a molybdenum-containing gas to remove a desired amount of a tungsten nitride passivation layer. While many of these features are taught by the prior art, the prior art does not teach all of these limitations in combination.
For example, Chang et al. (US 12,417,945) discloses a method in which a tungsten liner within an opening is exposed to nitrogen and removed prior to conductive fill. However, Chang is silent with regards to the use of a molybdenum-containing gas for removal. Furthermore, the nitrogen exposure does not inhibit growth of the nucleation layer at narrow portions within the opening, as the liner, which may be a seed layer, is already fully formed by that point in the process.
Zhou et al. (US 12,176,203), which is the closest prior art (see FIG. 18), teaches cyclical deposition to form the nucleation layer 96A and exposure to nitrogen to suppress growth of the subsequently deposited fill layer 96B at narrow portions. However, like Chang, the nucleation layer is already fully formed by the time of the nitrogen exposure, and thus the nitrogen exposure does not inhibit growth of the nucleation layer at narrow portions within the opening. Furthermore, there is no teaching or suggestion of any removal step of nitridized material, let alone removal by use of a molybdenum-containing gas.
Yoon et al. (US 11,482,452) teaches similar aspect as Zhou, except that the exposure is nitrogen plasma. However, like Zhou, there is no teaching or suggestion of any removal step of nitridized material, let alone removal by use of a molybdenum-containing gas.
Chen et al. (US 2021/0090948) and Matsuyama et al. (US 7,709,376) similarly teach many aspects of the claimed invention. However, they, like the other prior art references, do not teach the combination of exposure to a nitrogen-containing gas to inhibit growth of the nucleation layer at narrow portions within the opening and exposing the opening to a molybdenum-containing gas to remove a desired amount of a tungsten nitride passivation layer.
The Examiner acknowledges that the Mallick reference (WO 2018/156710) cited in the IDS generally teaches that a tungsten nitride material can be removed by a metal halide precursor, where the metal may be molybdenum. However, the removal is a total removal of a sacrificial material that may be replaced with a conductive material to form a metal pillar. This is not analogous to the removal of the tungsten nitride that is formed in the references above, which is a thin conformal layer within an opening that is later completely filled. If anything, the teaching of Mallick would be applicable to the fill materials of these references. As such, even considering the Mallick reference, the prior art does not teach the combination of exposure to a nitrogen-containing gas to inhibit growth of the nucleation layer at narrow portions within the opening and exposing the opening to a molybdenum-containing gas to remove a desired amount of a tungsten nitride passivation layer. Thus, claim 1 is found to be allowable. Claims 2 and6 recite the same features via dependency.
Conclusion
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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/DANIEL LUKE/Primary Examiner, Art Unit 2896