DETAILED ACTION
This office action is in response to the election filed 11/4/2025.
Currently, claims 1-20 are pending. Of these, claims 9-20 have been withdrawn from consideration.
Election/Restrictions
Applicant's election with traverse of Species I is acknowledged. The traversal is on the ground(s) that there is no search or examination burden, as a search the subject matter of Species I would yield relevant references that are equally applicable to Species II or III. This is not found persuasive because a search for one of the species is equivalent to a search for a reference that explicitly teaches away from another species. For instance, simultaneous formation (a feature of Species I) is equivalent to a search for a reference in which formation is not sequential (sequential formation being a feature of Species II). Thus, a search for references reading on Species II would require a different search with a different focus, which is burdensome.
The requirement is still deemed proper and is therefore made FINAL.
Specification
The disclosure is objected to because of the following informalities:
The numbering of the paragraphs is problematic. Particularly, there is a paragraph between paragraphs [0039] and [0040] that is numbered “[0002]”.
Furthermore, in several instances, the word “filing” is used instead of “filling”. See, for example, para. [0013], line 1; para. [0002] (between para. [0039] and [0040]), line 6; para. [0044, line 1.
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.
Claims 1-8 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Claim 1 recites the limitation “forming a passivation layer selectively on an exposed surface of a conductive layer within a via” in lines 3-4. It is not clear whether “within a via” applies to the passivation layer or the conductive layer. The disclosure shows the passivation layer being formed within the via, while the conductive layer is not formed in the via but rather below the via. See e.g. FIG. 3B. Thus, for purposes of examination, the limitation is understood to mean that it is the passivation layer that is formed within the via.
Furthermore, claim 1 recites the limitation “selectively filling the via with a first conductive material at least partially and simultaneously depositing the first conductive material on the barrier layer on the inner sidewalls of the via and the trench” in line 7. It is not clear what is meant by “selectively”, as the disclosure shows the conductive material being formed on all exposed surfaces, including outside of the trench (FIG. 3E). It would seem that “selectively” could refer to the conductive material being formed at a faster rate at the bottom of the via compared to the rate at the sidewalls. However, the specification seems to teach that this is not the case. From para. [0013]: “conductive material … is deposited, selectively or at a faster deposition rate, at a bottom of the via while deposited at a slower deposition rate, on the sidewalls of the via” (emphasis added). However, for purposes of examination, “selectively” is understood to mean that the material may be deposited on all exposed surfaces, but is preferentially formed at the bottom of the via relative to the other surfaces.
Further still, the limitation “the remaining” lacks antecedent basis in the claims. It is not clear to what this limitation refers, particularly whether it refers to a feature of the via or to the via and the trench (“the remaining of the via and the trench”). For purposes of examination, the limitation is understood to mean the portion of the trench that remains unoccupied after the selective filling step recited above.
However, “filling the via with a first conductive material at least partially” (line 7) allows for instances in which the via is filled partially or fully. In the case that the via is filled fully, it is not clear how the final claimed step of “filling the remaining of the via” could be achieved, as there would be no remaining portion of the via in which the first conductive material could be filled. For purposes of examination, the limitation is understood to mean partially filling the via such that a remaining portion of the via remains unoccupied.
Claims 2-8 recite the same limitations via dependency.
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 1-2 and 4-8 are rejected under 35 U.S.C. 103 as being unpatentable over Fang et al. (US 10,340,183) in view of Liu et al. (US 2022/0165616).
Pertaining to claim 1, Fang shows, with reference to FIG. 1-2 and 4, a method of selectively filling a via with a simultaneous liner deposition in a semiconductor structure, comprising:
forming a conductive layer (12) and a via (22a) formed in a dielectric layer (20) formed over the conductive layer;
forming a barrier layer (16’) on inner sidewalls of the via and a trench (22b) formed in the dielectric layer;
selectively filling the via with a first conductive material (26) at least partially and simultaneously depositing the first conductive material on the barrier layer on the inner sidewalls of the via and the trench (col. 4, lines 34-48; col. 3, line 60 – col. 4, line 10), to form a liner on the inner sidewalls of the via and the trench; and
filling the remaining of the via and the trench with a second conductive material (28).
Fang fails to show forming a passivation layer selectively on an exposed surface of the conductive layer within the via, and that the barrier layer is formed selectively on the inner sidewalls of the via.
However, Liu teaches with reference to FIG. 5-6, 15 and 18-21 that, for a similar method for forming an interconnect structure in a via 2091 and trench 2092, a passivation layer 601 is selectively formed on an exposed surface of conductive layer 115/117 prior to forming barrier layer 1501 (FIG. 6). With the passivation layer in place, the barrier layer 1501 is selectively formed on inner sidewalls of the via and trench (FIG. 15). See e.g. para. [0064].
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to form a passivation layer on the conductive layer of Fang in order to form the barrier layer selectively on the inner sidewalls of the via and the trench, as taught by Liu, with the motivation that the absence of the barrier layer at the bottom of the via results in reduced contact resistance (para. [0073]).
Pertaining to claim 2, Liu teaches removing the passivation layer from the surface of the conductive layer (FIG. 18), subsequent to the forming of the barrier layer (FIG. 15) and prior to the selective filling of the via with the first conductive material (FIG. 19).
Pertaining to claim 4, Liu teaches the passivation layer comprises a self- assembled monolayer (SAM) of organic molecules (para. [0046] – [0047]).
Pertaining to claim 5, both Fang and Liu teach the dielectric layer comprises low k dielectric (SiOCH), silicon dioxide (SiO2), silicon nitride (Si3N4), silicon carbide (SiC), aluminum oxide (Al2O3), or aluminum nitride (AlN) (Fang, col. 3, lines 33-41; Liu, para. [0033], [0029]).
Pertaining to claim 6, both Fang and Liu teach the barrier layer comprises tantalum nitride (TaN), metal doped TaN, titanium nitride (TiN), tungsten nitride (WN), or tungsten nitride carbide (WCN) (Fang, col. 3, lines 57-59; Liu, para. [0064]).
Pertaining to claim 7, both Fang and Liu teach the first conductive material comprises copper (Cu), cobalt (Co), molybdenum (Mo), tungsten (W), or ruthenium (Ru) (Fang, col. 3, lines 60-65; Liu, para. [0068]).
Pertaining to claim 8, both Fang and Liu teach the second conductive material comprises copper (Cu), cobalt (Co), ruthenium (Ru), or molybdenum (Mo) (Fang, col. 4, lines 23-26; Liu, para. [0069]).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Fang in view of Liu as applied to claim 1 above, and further in view of Wu et al. (US 6,093,639).
Fang in view of Liu teaches the method of claim 1, but fails to explicitly teach the step of performing a liner treatment process to densify the liner, the liner treatment process comprising a plasma treatment or a gas soak.
However, Wu teaches in col. 2, lines 50-53 that, in a similar method for forming an interconnect structure, the liner layer is densified by a plasma process prior to depositing the metal fill.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to densify the liner layer of Fang in view of Liu using a plasma process, as taught by Wu, with the motivation that the densification process prevents the formation of voids in the subsequently formed metal fill (col. 2, lines 60-63).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Liu (US 2022/0084937), Chin et al. (US 2022/0246534), Luo et al. (US 11,482,451), and Yu et al. (US 2021/0082750) all disclose inventions similar to Applicant’s.
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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