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 .
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
(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 1-10, 15-16, and 19-20 are rejected under 35 U.S.C. 102(a)(1)/(a)(2) as being anticipated by Ko et al. (US 20200328082 A1).
As to claim 1, Ko discloses a method of microfabrication [Abstract; Fig. 6], the method comprising:
providing a wafer having a patterned layer formed thereon [Fig. 1B], the patterned layer comprising a mandrel structure having a first sidewall and a second sidewall on opposing sides of the mandrel structure [Fig. 1B; Fig. 6, 601-602];
forming a first spacer on the first sidewall of the mandrel structure by asymmetric deposition, asymmetric etch or a combination thereof [Fig. 1C; Fig. 6, 603];
forming a second spacer on the second sidewall of the mandrel structure so that the first spacer, the mandrel structure and the second spacer form a three-material structure [Fig. 1D; Fig. 6, 604];
forming a first etch mask over the patterned layer [Fig. 5A-5B, para. 0059-62], the first etch mask comprising a first opening that exposes the three-material structure [Fig. 6, 605]; and
selectively removing one or two materials of the three-material structure via the first opening [Fig. 5A-5B, para. 0059-62; Fig. 6, 606].
As to claim 2, Ko discloses the method of claim 1, wherein: the first opening of the first etch mask is not aligned with the three-material structure in that at least one boundary of the first etch mask is outside the three-material structure [Fig. 5A-5B, para. 0059-62].
As to claim 3, Ko discloses the method of claim 2, wherein: the wafer comprises a top layer 504 that is in direct contact with the patterned layer [Fig. 5A], and the first opening of the first etch mask also exposes the top layer of the wafer [Fig. 5B, para. 0059-62].
As to claim 4, Ko discloses the method of claim 3, wherein: the first opening exposes four different materials consisting of the first spacer, the mandrel structure, the second spacer and the top layer [Fig. 5B, para. 0059-62].
As to claim 5, Ko discloses the method of claim 1, wherein the selectively removing comprises: selectively etching the first spacer, or both the first spacer and the mandrel structure, in the first opening [Fig. 5B, para. 0059-62].
As to claim 6, Ko discloses the method of claim 5, further comprising: removing the first etch mask; forming a second etch mask over the patterned layer, the second etch mask comprising a second opening that exposes the three-material structure; and selectively etching the second spacer, or both the second spacer and the mandrel structure, in the second opening [para. 0058, “one or more masks”; para. 0060, “one or more additional masks”].
As to claim 7, Ko discloses the method of claim 1, wherein the selectively removing comprises: selectively etching the second spacer, or both the second spacer and the mandrel structure, in the first opening [para. 0039, para. 0059-62].
As to claim 8, Ko discloses the method of claim 7, further comprising:
removing the first etch mask [Fig. 5A-5B, para. 0059-62];
forming a second etch mask over the patterned layer, the second etch mask comprising a second opening that exposes the three-material structure [Fig. 5A-5B, para. 0059-62]; and
selectively etching the first spacer, or both the first spacer and the mandrel structure, in the second opening [Fig. 5A-5B, para. 0059-62].
As to claim 9, Ko discloses the method of claim 1, further comprising:
forming a gap in the mandrel structure to divide the mandrel structure into two sub-mandrel structures that are spaced apart from each other by the gap; and filling the gap with the first spacer [para. 0025].
As to claim 10, Ko discloses the method of claim 9, further comprising:
forming a first spacer material isotropically around the mandrel structure, including in the gap [Fig. 1A]; and
executing a directional etch process that has an acute angle relative to a working surface of the wafer so that remaining portions of the first spacer material forms the first spacer that is on the first sidewall of the mandrel structure and fills the gap [Fig. 1B].
As to claim 15, Ko discloses the method of claim 1, wherein: the first spacer, the mandrel structure and the second spacer are configured to be etch-selective to each other [para. 0039, para. 0059-62].
As to claim 16, Ko discloses the method of claim 15, wherein:
the mandrel structure comprises silicon nitride, spin-on carbon [para. 0025], amorphous carbon, amorphous silicon, or a combination thereof,
the first spacer comprises silicon oxide, silicon nitride, titanium oxide, titanium nitride, or a combination thereof [para. 0032], and
the second spacer comprises silicon oxide, silicon nitride, titanium oxide, titanium nitride, or a combination thereof [para. 0032, para. 0034].
As to claim 19, Ko discloses the method of claim 16, wherein:
the wafer comprises a top layer 504 that is in direct contact with the patterned layer [Fig. 5A], and the top layer comprises silicon [para. 0028], germanium, silicon germanium, or a combination thereof .
As to claim 20, Ko discloses the method of claim 1, wherein:
the patterned layer comprises a plurality of mandrel structures that extend substantially parallel to one another [Fig. 5A].
Claims 1-10, 13-16, and 19-20 are rejected under 35 U.S.C. 102(a)(1)/(a)(2) as being anticipated by Schenker et al. (US 20200075334 A1).
As to claim 1, Schenker discloses a method of microfabrication [Abstract], the method comprising:
providing a wafer having a patterned layer formed thereon, the patterned layer comprising a mandrel structure having a first sidewall and a second sidewall on opposing sides of the mandrel structure [Fig. 1];
forming a first spacer on the first sidewall of the mandrel structure by asymmetric deposition, asymmetric etch or a combination thereof [Figs. 2-3];
forming a second spacer on the second sidewall of the mandrel structure so that the first spacer, the mandrel structure and the second spacer form a three-material structure [Fig. 4];
forming a first etch mask over the patterned layer, the first etch mask comprising a first opening that exposes the three-material structure [Fig. 7; para. 0050, “in another implementation, backbones 116 may not be removed…may be used to form some additional features in subsequent processes”]; and
selectively removing one or two materials of the three-material structure via the first opening [Figs. 7-11; para. 0051-52].
As to claim 2, Schenker discloses the method of claim 1, wherein: the first opening of the first etch mask is not aligned with the three-material structure in that at least one boundary of the first etch mask is outside the three-material structure [Figs. 7-11].
As to claim 3, Schenker discloses the method of claim 2, wherein: the wafer comprises a top layer 114B that is in direct contact with the patterned layer, and the first opening of the first etch mask also exposes the top layer of the wafer [Figs. 7-11].
As to claim 4, Schenker discloses the method of claim 3, wherein: the first opening exposes four different materials consisting of the first spacer, the mandrel structure, the second spacer and the top layer [Figs. 7-11].
As to claim 5, Schenker discloses the method of claim 1, wherein the selectively removing comprises: selectively etching the first spacer, or both the first spacer and the mandrel structure, in the first opening [Figs. 7-11].
As to claim 6, Schenker discloses the method of claim 5, further comprising:
removing the first etch mask [Figs. 8-11];
forming a second etch mask over the patterned layer, the second etch mask comprising a second opening that exposes the three-material structure [Figs. 9-11]; and
selectively etching the second spacer, or both the second spacer and the mandrel structure, in the second opening [Figs. 9-11].
As to claim 7, Schenker discloses the method of claim 1, wherein the selectively removing comprises: selectively etching the second spacer, or both the second spacer and the mandrel structure, in the first opening [Figs. 7-11];
As to claim 8, Schenker discloses the method of claim 7, further comprising:
removing the first etch mask [Figs. 8-11];
forming a second etch mask over the patterned layer, the second etch mask comprising a second opening that exposes the three-material structure [Figs. 9-11]; and
selectively etching the first spacer, or both the first spacer and the mandrel structure, in the second opening [Figs. 9-11];
As to claim 9, Schenker discloses the method of claim 1, further comprising: forming a gap in the mandrel structure to divide the mandrel structure into two sub-mandrel structures that are spaced apart from each other by the gap [para. 0039]; and filling the gap with the first spacer [para. 0040].
As to claim 10, Schenker discloses the method of claim 9, further comprising:
forming a first spacer material isotropically around the mandrel structure, including in the gap [para. 0041]; and
executing a directional etch process that has an acute angle relative to a working surface of the wafer so that remaining portions of the first spacer material forms the first spacer that is on the first sidewall of the mandrel structure and fills the gap [para. 0043, Fig. 3; para. 0049, Fig. 5].
As to claim 13, Schenker discloses the method of claim 1, wherein the first spacer is formed on the first sidewall of the mandrel structure at least by the asymmetric etch [para. 0043, Fig. 3; para. 0049, Fig. 5] that comprises:
forming a first spacer material on the first sidewall of the mandrel structure and on the second sidewall of the mandrel structure [Fig. 2; Fig. 4]; and
removing the first spacer material from the second sidewall of the mandrel structure by a directional etch process that has an acute angle relative to a working surface of the wafer [Fig. 3; Fig. 5].
As to claim 14, Schenker discloses the method of claim 13, further comprising: executing an anisotropic etch process that is substantially perpendicular to the working surface of the wafer to etch the first spacer material [para. 0042; para. 0047].
As to claim 15, Schenker discloses the method of claim 1, wherein: the first spacer [para. 0040], the mandrel structure [para. 0038] and the second spacer are configured to be etch-selective to each other [para. 0044-46].
As to claim 16, Schenker discloses the method of claim 15, wherein:
the mandrel structure comprises silicon nitride [para. 0038], spin-on carbon, amorphous carbon [para. 0038], amorphous silicon [para. 0038], or a combination thereof,
the first spacer comprises silicon oxide, silicon nitride, titanium oxide, titanium nitride, or a combination thereof [para. 0040], and
the second spacer comprises silicon oxide, silicon nitride, titanium oxide, titanium nitride, or a combination thereof [para. 0040, para. 0044-46].
As to claim 19, Schenker discloses the method of claim 16, wherein: the wafer comprises a top layer 114A that is in direct contact with the patterned layer [Fig. 1], and the top layer comprises silicon, germanium, silicon germanium, or a combination thereof [para. 0034].
As to claim 20, Ko discloses the method of claim 1, wherein: the patterned layer comprises a plurality of mandrel structures that extend substantially parallel to one another [Fig. 1].
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 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Ko et al. (US 20200328082 A1), as applied to claims 1-10, 15-16, and 19-20 above.
As to claim 17, Ko discloses the method of claim 16, but fails to explicitly disclose wherein:
the mandrel structure comprises silicon nitride, one of the first spacer and the second spacer comprises silicon oxide, and the other one of the first spacer and the second spacer comprises titanium oxide, titanium nitride, or a combination thereof.
However, Ko fails to explicitly disclose the exact materials scheme above. However, Ko teaches the mandrel structure may be formed from hardmask material [para. 0025] the spacers may be formed of silicon oxide or silicon nitride [para. 0030], the capping layers may comprise a variety of materials (e.g., silicon oxide, silicon nitride, titanium oxide, titanium nitride) [para. 0032], and that each layer is formed to be selectively removable from the pattern [Abstract].
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to select from the suggested materials for the mandrel and capping materials, to select silicon nitride for the mandrel (a well-known hard mask material), silicon oxide for a capping material, and titanium oxide or nitride for the second capping material, in order to achieve a multi-pattern structure capable of being selectively etched, as taught by Ko [Abstract].
Additionally, the simple substitution of one known element for another is likely to be obvious when predictable results are achieved. See MPEP § 2143, B. Here, selecting silicon nitride as a hardmask material would provide the predictable result of forming a mandrel capable of use within the materials scheme of the process of Ko.
As to claim 18, Ko discloses the method of claim 16, but fails to explicitly disclose wherein:
the mandrel structure comprises amorphous silicon, one of the first spacer and the second spacer comprises titanium oxide, and the other one of the first spacer and the second spacer comprises silicon oxide.
However, Ko fails to explicitly disclose the exact materials scheme above. However, Ko teaches the mandrel structure may be formed from hardmask material [para. 0025] the spacers may be formed of silicon oxide or silicon nitride [para. 0030], the capping layers may comprise a variety of materials (e.g., silicon oxide, silicon nitride, titanium oxide, titanium nitride) [para. 0032], and that each layer is formed to be selectively removable from the pattern [Abstract].
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to select from the suggested materials for the mandrel and capping materials, to select amorphous silicon for the mandrel (a well-known hard mask material), silicon oxide for a capping material, and titanium oxide or nitride for the second capping material, in order to achieve a multi-pattern structure capable of being selectively etched, as taught by Ko [Abstract].
Additionally, the simple substitution of one known element for another is likely to be obvious when predictable results are achieved. See MPEP § 2143, B. Here, selecting amorphous silicon as a hardmask material would provide the predictable result of forming a mandrel capable of use within the materials scheme of the process of Ko.
Claims 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Schenker, as applied to claims 1-10, 13-16, and 19-20 above, and further in view of Nemani et al. (US 20150294863 A1).
As to claim 11, Schenker discloses the method of claim 1, further comprising
removing the first spacer material from the top surface of the mandrel structure by an anisotropic etch process so that remaining portions of the first spacer material forms the first spacer [para. 0042; para. 0047].
Schenker fails to explicitly disclose:
wherein the first spacer is formed on the first sidewall of the mandrel structure at least by the asymmetric deposition that comprises:
forming a first spacer material on the first sidewall of the mandrel structure and on a top surface of the mandrel structure by a directional plasma that has an acute angle relative to a working surface of the wafer.
However, Nemani discloses a selective atomic layer deposition process [Abstract], comprising:
forming a first spacer material on the first sidewall of the mandrel structure and on a top surface of the mandrel structure by a directional plasma that has an acute angle relative to a working surface of the wafer [para. 0063-65, Fig. 8B2-3—Fig. 8D5].
Here, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of forming an asymmetric spacer by deposition and etching, of Schenker, to include the method of asymmetric spacer deposition, of Nemani, as an alternative process of forming a spacer on single sidewall of a mandrel, as taught by Nemani [Abstract; para. 0063-65].
As to claim 12, modified Schenker discloses the method of claim 11, wherein: the acute angle is 30°-85° [Nemani, para. 0063-65].
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: The additionally cited references are cited to show methods of self aligned double patterning or multiple patterning comprising forming asymmetrical spacers [Abstracts].
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHRISTOPHER M REMAVEGE whose telephone number is (571)270-5511. The examiner can normally be reached Monday-Friday 10:00 AM - 3:30 PM.
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/CHRISTOPHER REMAVEGE/Examiner, Art Unit 1713
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