DETAILED ACTION
This action is responsive to the application No. 18/755,686 filed on June 27, 2024.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
Acknowledgement is made of Applicant’s Information Disclosure Statement (IDS) form PTO-1449. The IDS has been considered.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-5 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claims 1-5 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for forming a protective layer by reacting citric acid with copper, does not reasonably provide enablement for all possible combinations of conductive materials and all possible acidic solutions. The specification does not enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to use the invention commensurate in scope with these claims.
Claim 1 recites the protective layer comprises a compound of an acid and a material of the conductive layer, and the protective layer has an ability to resist a hydrofluoric acid etching. As best understood, this limitation broadly includes all known conductive material compositions (e.g. all metals, metal alloys, semiconductors, semiconductor alloys, conductive polymers, conductive organic compounds, combinations thereof, etc.), all possible acid solutions, and every possible combination thereof, to form a compound (not every combination will form a solid compound, precipitate, or residue) that includes a part of the acid and a material of the conductive layer. Looking to the specification for support for this limitation encompassing billions of possible combinations and resulting compounds, Applicant only provides one specific example: the combination of copper and citric acid to form a protective layer of undisclosed composition. There is no disclosure of any other conductive materials, acids, or any resulting protective layer compositions, nor guidance with respect to what combinations form compounds and their ability to resist unknown HF etching conditions. Applicant has not demonstrated possession of the generic claim drawn to all possibilities. The written description does not provide support for the full scope of the claim encompassing all possible conductive materials, all possible acidic solutions, and all possible resulting compounds from every possible combination. The specification only describes one combination, while the claims encompass all known and unknown combinations. “[T]he description of one method for creating a seamless DWT does not entitle the inventor . . . to claim any and all means for achieving that objective.” See LizardTech, 424 F.3d at 1346, 76 USPQ2d at 1733. The written description does not allow one to make and use the full scope of the claimed invention. The Federal Circuit has repeatedly held that "the specification must teach those skilled in the art how to make and use the full scope of the claimed invention without ‘undue experimentation’." In re Wright, 999 F.2d 1557, 1561, 27 USPQ2d 1510, 1513 (Fed. Cir. 1993). The full scope of the claimed invention includes the billions of possible combinations encompassed by claim 1, and is clearly in the realm of undue experimentation. Applicant provides no other working examples regarding any other conductive materials, acids, or which combinations provide resulting compounds, or guidance as to what compounds would actually work in an interconnect structure since this protective layer is embedded in the final structure so there would be additional considerations with respect to stability, conductivity, compatibility with the surrounding materials in the device. There are no known tables of new compounds that would form from various combinations of conductive materials and different acids and/or mixtures thereof and their relative abilities to resist HF etching. For example, if one were to expose a conductive material such as a layer of titanium silicide on a Cu-Zn-Pb-Sn metal alloy to a mixture of lactic acid, ascorbic acid, and sulfuric acid, does this form a compound as claimed and what is the etch rate of the resulting compound in a buffered HF solution? The Examiner cannot find these details in the specification or anywhere else. One would need to experimentally determine the ability of billions of possible combinations to determine which ones form a compound, and further determine which resulting compounds subjectively resist HF etching, under unknown etching conditions.
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 1-5 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 1 recites the protective layer comprises a compound of an acid and a material of the conductive layer, and the protective layer has an ability to resist a hydrofluoric acid etching, thereby rendering the claim indefinite. It is unclear what is actually required by the “…a compound of an acid and a material of the conductive layer…”. It is not clear how much of the compound of or from the acid is required and how much of the material of the conductive layer is required. For example, since there are acids that comprise oxygen, does Applicant consider all metal oxides or semiconductor oxides to be compounds of an acid and a material of the conductive layer, especially if no acid is used in the formation of the oxide? Since no materials are recited in the claim and no composition of the protective layer is disclosed, one would need to guess what compositions would be included or excluded in this limitation.
Next, it is unclear how the claimed “…the protective layer has an ability to resist a hydrofluoric acid etching…” is supposed to be interpreted and to what subjective degree this protective layer needs to resist HF etching. It is unclear under what the conditions (e.g. composition, concentration, temperature, etc.) the layer must resist the HF etching. Some material-acid combinations only etch when at elevated temperatures. For example, would a layer having a very slow etch rate, perhaps further reduced by using low temperature and a highly diluted HF solution, meet this limitation, if a concentrated mixture of HF + other acid(s)/additives, at an elevated temperature has a much faster etch rate? According to the specification, the only metal recited is copper, and HF is not generally known to etch copper. Lastly, it is unclear what Applicant regards as “ability to resist”… etching, since this subjective term of degree is not defined in the claims or specification.
Since copper may be formed by plating using an aqueous solution of copper sulfate, which is a known acidic copper solution (pH ~41), then the deposited copper would comprise copper from the acid plating solution while forming a copper layer, which would also comprise copper already deposited, the new copper atoms bonding to existing/previously deposited copper atoms, then the protective layer is an interface thickness of copper, and copper is naturally resistant to HF etching2. This will be assumed for the purpose of examination, i.e. since copper can be formed in this manner, a copper layer meets the limitations of the protective layer comprises a compound of an acid and a material of the conductive layer, and the protective layer has an ability to resist a hydrofluoric acid etching.
The following is a quotation of 35 U.S.C. 112(d):
(d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph:
Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.
Claim 4 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends. Claim 4 recites the citric acid has a pH in a range between two and four. As best understood, reciting the pH of the citric acid wherein the acid is only necessary to provide possible elements for the compound in claim 1, does not change the composition of the acid in any meaningful way, i.e. citric acid with a pH of 2 still has the same H, C, and O atoms as citric acid with a pH of 6, thus the available atoms to form a compound are the same. Reciting the pH of citric acid does not further limit the device of claim 1 as this would not result in any change in structure or composition. Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
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 5 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Beck (US 2006/0194430).
(Re Claim 1) Beck teaches a semiconductor structure, comprising:
a semiconductor integrated circuit having a conductive layer (Fig. 9: 202);
a first oxide layer (214, ¶38) located on the semiconductor integrated circuit, wherein the conductive layer of the semiconductor integrated circuit is exposed from a top surface of the first oxide layer (Fig. 9);
an etch stop layer (208) located on a top surface of the first oxide layer and covering the conductive layer;
a second oxide layer (206, ¶35) located on the etch stop layer;
a through via (210) extending through the second oxide layer and the etch stop layer to expose the conductive layer, wherein the through via is filled with a conductive material (230); and
a protective layer located between the conductive layer and the conductive material, wherein the protective layer is located at a bottom of the conductive material, the protective layer comprises a compound of an acid and a material of the conductive layer, and the protective layer has an ability to resist a hydrofluoric acid etching (the protective layer is the Cu layer interface between Cu layer 230 and Cu layer 202, Cu is resistant to HF etching, and Cu is a component of an acid, for example aqueous copper sulfate, also see discussion above following the §112(b) rejection).
(Re Claim 2) wherein the material of the conductive layer comprises copper (¶65).
(Re Claim 5) further comprising: a trench recessed from a top of the second oxide layer, wherein the trench is aligned with the through via, a width of the trench is greater than a width of the through via, and the through via is located within the trench (see Figs. 8-9, 212).
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 3 and 4 are rejected under 35 U.S.C. 103 as being unpatentable over Beck as applied above, and further in view of Andricacos et al. (US 2002/0115292).
(Re Claim 3) wherein the acid comprises citric acid.
(Re Claim 4) wherein the citric acid has a pH value in a range between two and four.
Beck is silent regarding citric acid, understood to mean the compound includes at least one of C, O, or H, also see §112 rejections above. Started differently, Beck is silent regarding the Cu interface discusses above further includes at least one of C, O, or H. A PHOSITA would be motivated to loot to related art to teach possible improvements over Beck’s process. Related art from Andricacos teaches doping the copper with impurities such as C and O, elements found in citric acid, to form electromigration-resistant copper (¶¶24,26). A PHOSITA would find it obvious to dope Beck’s copper (202 and 230) with C or O to reduce electromigration. With respect to the pH, a pH of citric acid is normally within the claimed range, however this is immaterial to the fact that the copper will include a compound from the C or O dopants, elements in citric acid, bonded to surrounding copper, regardless of a pH of the citric acid, also see §112 discussion above.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The additional cited art teaches related interconnect structures.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIK T. K. PETERSON whose telephone number is (571)272-3997. The examiner can normally be reached M-F, 9-5 pm (CST).
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/ERIK T. K. PETERSON/Primary Examiner, Art Unit 2898
1 see ¶26 in Yang et al. (US 2004/0016647), ¶465 in Shimizu et al. (US 2009/0008142), ¶29 in Sun et al. (US 2005/0109627)
2 see Williams et al., Table VI, p. 767.
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