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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 2/16/2026 has been entered.
Status of Claims
The following is in response to the communication filed 2/16/2026.
Claims 1-20 are currently pending.
Claims 1 and 11 have been amended.
Claims 17-20 have been withdrawn.
Claims 1-16 have been examined.
Response to Arguments
Applicant’s arguments, see page 6, filed 2/16/2026, with respect to 35 U.S.C. §112 have been fully considered and are persuasive. The rejections of 2/16/2026 of claims 1-16 with regards to 112(a) and 112(b) has been withdrawn.
Applicant’s arguments, see page 7, filed 2/16/2026, with respect to the rejections of claims 1-16 in specific to claims 1 and 11 under 35 U.S.C. §103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new grounds of rejection is made in view of Chandrashekar et al. US 20130302980 A1. See below for more detail.
Claim Objections
Claim 10 is objected to because of the following informalities:
Claim 10 recites “the etchant gas comprises an inert gas,” but for clarity should recite “the etchant gas further comprises an inert gas”. As written claim 10 could reasonable be interpreted to be further broadening in a dependent claim instead of further narrowing.
Appropriate correction is required.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-3 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Chandrashekar et al. US 20130302980 A1 (hereinafter Chandrashekar).
Regarding claim 1, Chandrashekar discloses:
A method of forming an interconnect structure over a substrate (Chandrashekar, Fig. 1B and 2A, Summary), comprising:
forming a nucleation layer (Fig. 1B, [0043] under-layer 113 being a nucleation layer.) over a surface of the substrate (substrate 103), wherein the surface of the substrate comprises a plurality of openings,(hole 105) and the process of forming the nucleation layer (Process in Fig. 2A.) comprises:
(a) exposing the substrate to a tungsten-containing precursor gas to form a tungsten-containing layer over a surface of each of the plurality of openings; (Fig. 2A, step 201a includes introducing a tungsten-containing precursor.)
(b) exposing the formed tungsten-containing layer to an etchant gas, (Fig. 2A, step 201a includes introducing a reducing agent) wherein exposing the tungsten-containing layer to the etchant gas etches at least a portion of the tungsten-containing layer disposed at a top region of each of the plurality of openings; and ([0070], [the] process involves etching a pinched-off via to remove tungsten from the pinch point (i.e. top region of the opening).)
(c) repeating (a) and (b) one or more times; and ([0068], the process is done by sequentially pulsing the precursor gas and the reducing/etching agent.)
forming a bulk layer over the formed nucleation layer. (Step 201b forming the bulk layer.)
Regarding claim 2, Chandrashekar further discloses:
wherein the tungsten-containing precursor gas is selected from the group consisting of tungsten hexafluoride (WF6), tungsten hexachloride (WC16), and a combination thereof. ([0159], the tungsten containing precursor is WCL6.)
Regarding claim 3, Chandrashekar further discloses:
wherein exposing the formed tungsten- containing layer to the etchant gas to etch the formed tungsten-containing layer is a thermal based etching process that is performed at a temperature between 20 °C and 550 C. ([0094], etch of tungsten can be done at 100 °C or less.)
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 4, 5, 7, 8, and 11-16 are rejected under 35 U.S.C. 103 as being unpatentable over Chandrashekar in view of Toda et al. US 20220020601 A1 (hereinafter Toda).
Regarding claim 4, Chandrashekar discloses the elements of claim 3 as recited above.
Chandrashekar does not appear to disclose "the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide".
Toda, which teaches depositing molybdenum or tungsten films (Abstract), discloses:
the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide (Abstract; [0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
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 device of Chandrashekar to use a molybdenum-based etchant gas as taught by Toda for purpose of selectively etching a tungsten film due to the high selectivity of etching tungsten films with respect to silicon. (Toda, [0031].)
Regarding claim 5, Chandrashekar and Toda disclose the elements of claim 4 as recited above.
Toda further discloses:
the etchant gas comprises molybdenum fluoride (MoF6) (Abstract; [0042]: ST3- supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
Regarding claim 7, Chandrashekar and Toda disclose the elements of claim 1 as recited above.
Chandrashekar does not appear to disclose "the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide".
Toda, which teaches depositing molybdenum or tungsten films (Abstract), discloses:
the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide (Abstract; [0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
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 device of Chandrashekar to use a molybdenum-based etchant gas as taught by Toda for purpose of selectively etching a tungsten film due to the high selectivity of etching tungsten films with respect to silicon. (Toda, [0031].)
Regarding claim 8, Chandrashekar and Toda disclose the elements of claim 7 as recited above.
Toda further discloses:
the etchant gas comprises molybdenum fluoride (MoF6) ([0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
Regarding claim 11, Chandrashekar discloses:
A method of depositing a tungsten-containing layer, (Chandrashekar, Fig. 1B and 2A, Summary) comprising:
performing a nucleation process (process in Fig. 2A.) in a processing chamber, (Fig. 24, [0200], chamber 2418 for fabricating a device with the process.) the nucleation process comprising:
forming a tungsten-containing layer (Fig. 1B, under-layer 113) on a substrate (substrate 103) to by exposing a surface of the substrate a first tungsten-containing precursor gas, (Fig. 2A, step 201a includes introducing a tungsten-containing precursor. [0159], the tungsten containing precursor is WCL6.) wherein the surface of the substrate comprises a plurality of openings;
etching a portion of the formed tungsten-containing layer disposed at a top region of each of the plurality of openings ([0070], [the] process involves etching a pinched-off via to remove tungsten from the pinch point (i.e. top region of the opening).) by delivering …etchant gas to the substrate, (Fig. 2A, step 201a includes introducing a reducing agent.) repeating forming of the tungsten-containing layer and etching the formed tungsten-containing layer; ([0068], the process is done by sequentially pulsing the precursor gas and the reducing/etching agent.)
and performing a deposition process (Step 201b forming the bulk layer.) in the processing chamber, (Fig. 24, [0200], chamber 2418 for fabricating a device with the process.) the deposition process comprising forming a bulk layer by flowing a second tungsten-containing precursor gas. ([0163], the tungsten-containing precursor for bulk deposition is WF6.)
Chandrashekar does not appear to specifically disclose that the etch gas is “a molybdenum-based etchant gas.”
Toda, which teaches depositing molybdenum or tungsten films (Abstract), discloses:
the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide (Abstract; [0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide)
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 device of Chandrashekar to use a molybdenum-based etchant gas as taught by Toda for purpose of selectively etching a tungsten film due to the high selectivity of etching tungsten films with respect to silicon. (Toda, [0031].)
Regarding claim 12, Chandrashekar and Toda disclose all the elements of claim 11.
Chandrashekar further discloses:
repeating the nucleation process. ([0068], the process is done by sequentially pulsing the precursor gas and the reducing/etching agent.)
Regarding claim 13, Chandrashekar and Toda disclose all the elements of claim 11.
Chandrashekar further discloses:
wherein the first and second tungsten-containing precursor gases are each selected from the group consisting of tungsten hexafluoride (WF6), tungsten hexachloride (WC16), and a combination thereof. ([0159] and [0163], the tungsten containing precursor is WCL6 and the tungsten-containing precursor for bulk deposition is WF6.)
Regarding claim 14, Chandrashekar and Toda disclose all the elements of claim 11.
Chandrashekar further discloses:
wherein the etching of the formed tungsten- containing layer is performed at a temperature between 20 °C and 550 °C. ([0094], etch of tungsten can be done at 100 °C or less.)
Regarding claim 15, Chandrashekar and Toda teach the elements of claim 11 as recited above.
Toda further disclose:
the etchant gas comprises a molybdenum halide or a molybdenum oxy-halide ([0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
Regarding claim 16, Chandrashekar and Toda teach the elements of claim 14 as recited above.
Toda further discloses:
the etchant gas comprises molybdenum fluoride (MoF6). ([0042]: ST3-supplying MoF6 as the first etching gas; Fluorine (F) is a halide).
Claims 6, 9, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Chandrashekar and Toda as applied to claims 5 and 8 above, and further in view of Kong et al. “First principles study of inert-gas (helium, neon, and argon) interactions with hydrogen in tungsten” (hereinafter Kong).
Regarding claim 6, Chandrashekar and Toda disclose the elements of claim 5 as recited above.
Chandrashekar further discloses that “the etchant gas comprises argon (Ar)” (Chandrashekar, [0170].)
While Chandrashekar does disclose using other inert gases as well as argon. (Chandrashekar, [0170].) Neither Chandrashekar or Toda specifically disclose the etchant gas comprises argon (Ar) “and a hydrogen containing gas.”
Kong, which teaches the ion incident energy of hydrogen and inert-gas in a plasma generator (Kong, Introduction, p. 128.) discloses
using an inert gas such as argon and others. (Abstract, page 128, hydrogen gas is used with an inert-gas like argon.)
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 device of Chandrashekar and Toda to have the etchant gas comprises argon (Ar) and a hydrogen containing gas as taught by Kong for purposes of having the inert gas interrupt the diffusion of hydrogen into tungsten. (Kong, Abstract.)
Regarding claim 9, Chandrashekar and Toda disclose the elements of claim 8 as recited above.
While Chandrashekar does disclose using other inert gases as well as argon. (Chandrashekar, [0170].) Neither Chandrashekar or Toda specifically disclose the etchant gas comprises “wherein the etchant gas comprises a hydrogen containing gas.”
Kong, which teaches the ion incident energy of hydrogen and inert-gas in a plasma generator (Kong, Introduction, p. 128.) discloses
the etchant gas comprises a hydrogen containing gas. (Abstract, page 128, hydrogen gas is used with an inert-gas like argon.)
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 device of Chandrashekar and Toda to have the etchant gas comprises a hydrogen containing gas as taught by Kong for purposes of having the inert gas interrupt the diffusion of hydrogen into tungsten. (Kong, Abstract.)
Regarding claim 10, Chandrashekar, Toda, and Kong disclose the elements of claim 9 as recited above.
Chandrashekar further discloses:
wherein the etchant gas comprises an inert gas. (Chandrashekar, [0170] the etchant gas includes argon. )
Conclusion
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/HEIM KIRIN GREWAL/ Examiner, Art Unit 2812
/DAVIENNE N MONBLEAU/ Supervisory Patent Examiner, Art Unit 2812