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 § 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.
Rejection Note: Italicized claim limitations indicate limitations that are not explicitly disclosed in the primary reference (or combination of references), but are disclosed or rendered obvious by secondary references or remarks.
Claims 1-3, 6, 15-18, 20-21, and 24-25 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 20170263505 A1) in view of Juengling (US 20070205438 A1), Zhao (US 20210082667 A1), and Tsai (US 20190067020 A1).
Regarding claim 1, Wang discloses a method, comprising:
forming a plurality of hard mask layers (Fig. 2: 230 and 220) over a substrate (210) of a semiconductor device, wherein the plurality of hard mask layers comprises a first hard mask layer (220) and a second hard mask layer (230) above the first hard mask layer (vertically above, See annotated Fig. 3 for direction designation);
forming mandrels and spacers over the plurality of hard mask layers;
performing, using a plasma-based etch tool ([0014]: “a biased plasma etching process”), a pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed to form a first pattern in the second hard mask layer (the resultant 230 of Fig. 3; [0014]: “etched through the patterned resist”), and a second pattern in the first hard mask layer (the resultant 220 of Fig. 3; [0014]: “etched through the patterned resist”), based on the mandrels and the spacers,
wherein the forming of the first pattern removes the spacers and portions of the first hard mask layer (The “portions” being some of those of Fig. 2: 220 that have been removed in Fig. 3. Note: Wang describes a single etch for patterning layers 230 and 220, thus “forming of the first pattern” also includes removing “portions of the first hard mask layer” because it is grouped with forming “a second pattern in the first hard mask layer”; [0013]: “a subsequent etch”),
wherein the forming of the second pattern is after the forming of the first pattern (“after” is a necessary sequence in the reference because layer 230 must be exposed to etching before layer 220 is ever reached by etching) and removes the mandrels,
wherein the first pattern comprises a first width (Note: the “first width” is measured along a width direction. See annotated figure for width and direction designation) between portions of the second hard mask layer (between portions of 230 corresponding to 310A/310C), and
wherein the second pattern comprises a second width (Note: the “second width” is measured along the same width direction. See annotated figure) between portions of the first hard mask layer (between portions of 220 corresponding to 310A/310C), wherein the second width is greater than the first width;
etching the substrate based on the first pattern and the second pattern in the plurality of hard mask layers to form one or more fin structures for the semiconductor device from the substrate (Fig. 3: 310, annotated as 310A-310C; [0014]: “etched…to form fins”); and
forming a gate structure over the one or more fin structures ([0028]: “gate…stacks are formed over…the fins”).
Illustrated below is a marked and annotated figure of Fig. 3 of Wang.
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Wang fails to teach the method including
“forming mandrels and spacers over the plurality of hard mask layers;
performing, using a plasma-based etch tool, a pulsing technique in which a high- frequency radio frequency (RF) source and a low-frequency RF source are pulsed to form a first pattern in the second hard mask layer, and a second pattern in the first hard mask layer, based on the mandrels and the spacers,
wherein the forming of the first pattern removes the spacers and portions of the first hard mask layer,
wherein the forming of the second pattern is after the forming of the first pattern and removes the mandrels,
wherein the first pattern comprises a first width between portions of the second hard mask layer, and
wherein the second pattern comprises a second width between portions of the first hard mask layer, […];”
Juengling discloses a method including
forming mandrels (Fig. 7: 212) and spacers (216) over the plurality of hard mask layers (layers 210 and 211);
[…] to form a first pattern in the second hard mask layer (resultant 211), and a second pattern in the first hard mask layer (resultant 210), based on the mandrels and the spacers (Fig. 7 shows the resultant shapes of 211 and 210 correspond to the shape of mandrels/spacers 212/216, thus “based on”),
wherein the forming of the first pattern removes the spacers and portions of the first hard mask layer (The conclusion of all relevant steps pertaining to forming 211 is shown in Fig. 8, where the spacers 216 are not included in the resultant structure. Therefore, the spacers are removed. Portions of intermediate 210 have been removed before reaching the conclusion of the forming of the resultant 211 shown in Fig. 7),
wherein the forming of the second pattern is after the forming of the first pattern (“after” is a necessary sequence in the reference because layer 211 must be exposed to etching before layer 210 is ever reached by etching) and removes the mandrels (The conclusion of all relevant steps pertaining to forming 210 is shown in Fig. 8, where the mandrels 212 are not included in the resultant structure. Therefore, the mandrels are removed.),
wherein the first pattern comprises a first width (Y width) between portions of the second hard mask layer (between portions of 211 corresponding to neighboring 304), and
wherein the second pattern comprises a second width (Y width) between portions of the first hard mask layer (between portions of 210 corresponding to neighboring 304), […];
Modifying the method of forming the first and second patterns of Wang by including the method steps of Juengling would arrive at the claimed mandrels and spacers method configuration. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation the resultant first and second patterns perform the function of a mask (Wang: Fig. 3; Juengling: Fig. 7). Juengling provides a teaching to motivate one of ordinary skill in the art before the effective filing date to modify the method in that it would enable a simplified manufacturing process, thereby enhancing manufacturing efficiency ([0082]: “advantageously enable the forming of…devices…with a single mask”). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have the claimed mandrels and spacers method configuration because it would enhance manufacturing efficiency. MPEP 2143 (I)(G).
Illustrated below is a marked and annotated figure of Fig. 7 of Juengling.
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Wang in view of Juengling teaches the plasma-based etch tool (Wang) but fails to teach “a pulsing technique in which a high- frequency radio frequency (RF) source and a low-frequency RF source are pulsed”.
Zhao discloses a method using a plasma-based etch tool ([0121]: “plasma processing apparatus”), and further discloses the plasma-based etch tool performing a pulsing technique ([0121]: “Pulsed plasma processes”) in which a high-frequency radio frequency (RF) source ([0121]: f1; Fig. 10A) and a low-frequency RF source ([0121]: f2; Fig. 10A) are pulsed to form a pattern in a layer ([0121]: “for forming gate structures, spacer structures, self-aligned contact structures, and the like”).
Modifying the method of Wang in view of Juengling by having the plasma-based etch tool perform the pulsing technique disclosed by Zhao would arrive at the claimed tool configuration. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used (Wang: [0014]: “a biased plasma etching process”; Zhao: [0121]: “Pulsed plasma processes”). Zhao provides a teaching to motivate one of ordinary skill in the art before the effective filing date to modify the method in that it would improve manufacturing control when using the plasma-based etch tool, thereby improving manufacturing resilience ([0123]: “precise RF power control”). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have the claimed pulsing technique because it would improve manufacturing resilience. MPEP 2143 (I)(G).
Illustrated below is a marked and annotated figure of Figs. 10A-10C of Zhao.
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Wang in view of Juengling and Zhao teaches the first and second widths but fails to teach the claimed configuration:
“wherein the first pattern comprises a first width between portions of the second hard mask layer, and
wherein the second pattern comprises a second width between portions of the first hard mask layer, wherein the second width is greater than the first width;”
Tsai discloses sing a plasma-based etch tool ([0033]: “plasmas”) when forming a first pattern in the second hard mask layer (Fig. 9: pattern 214), and a second pattern in the first hard mask layer (pattern 212),
wherein the first pattern comprises a first width (See annotated figure for Width direction) between portions of the second hard mask layer (between portions of 214 corresponding to neighboring 902), and
wherein the second pattern comprises a second width (See annotated figure for Width direction) between portions of the first hard mask layer (between portions of 212 corresponding to neighboring 902), wherein the second width is greater than the first width ([0032]: “relatively larger tapering profile” indicates at least some amount of tapering exists in all disclosed hard mask layers; tapering is shown for 214/212 in region 204);
It would have been obvious to one having ordinary skill in the art before the effective filing date to have the claimed first and second width configuration because it is a resultant width configuration produced by a plasma-based etch tool. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used on a mask (Wang: [0014]: “a biased plasma etching process”; Tsai: [0033]: “plasmas”). Tsai provides a teaching to motivate one of ordinary skill in the art before the effective filing date to include the claimed width configuration because it would enable enhanced control over resultant device sizes, thereby improving manufacturing capabilities ([0012]: “maintained the same width, leading to…enlarged process window”). Therefore, the claim would have been obvious to one of ordinary skill in the art before the effective filing date because it would enable improved manufacturing capabilities. MPEP 2143 (I)(G).
Illustrated below is a marked and annotated figure of Fig. 9 of Tsai.
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Regarding claim 2, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 1 (Zhao: Fig. 10B), wherein the high-frequency RF source and the low-frequency RF source are pulsed such that first on durations for the high-frequency RF source and second on durations for the low-frequency RF source are non-overlapping ([0122]: “non-overlapping in…the time domain”).
Regarding claim 3, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 2 (Zhao: Fig. 10B), wherein at least one of:
a starting time of an on duration of the second on durations occurs after an offset time duration from a starting time of an on duration of the first on durations (A plurality of first and second on durations are illustrated, each of which has a starting time shown by the beginning of the pulse. These first and second on durations are non-overlapping, thus an offset time duration must necessarily exist.), or
a duty cycle of the second on durations is greater relative to a duty cycle of the first on durations.
Regarding claim 6, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 1 (Zhao: Fig. 10B), wherein the pulsing technique, in which the high-frequency RF source and the low-frequency RF source are pulsed, reduces a magnitude of a reduction in a height of the plurality of hard mask layers ([0133]: “anisotropic etching process”; “reduces” as claimed reasonably including comparisons to isotropic etching methods, therefore the anisotropic pulsing technique of Zhao reduces height reduction when compared to isotropic etching techniques).
Regarding claim 21, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 1 (Zhao: Fig. 10B), wherein the forming of the second pattern reduces a height of the first pattern ([0133]: “isotropically etching” necessarily etches in all directions including a height direction, therefore the isotropic pulsing technique of Zhao reduces a height).
Regarding claim 24, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 1 (Tsai: Fig. 9), wherein, after forming the first pattern, the second hard mask layer has parallel sides (parallel top/bottom sides. See annotated figure for side designation), and wherein, after forming the second pattern, the first hard mask layer has parallel sides (parallel top/bottom sides. See annotated figure for side designation).
Regarding claim 25, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 1 (Wang: Fig. 3), wherein etching the substrate to form the one or more fin structures comprises:
removing the portions of the second hard mask layer to form the one or more fin structures (this is shown in the progression from Fig. 2 to Fig. 3, where portions of 230 are removed),
wherein the portions of the first hard mask layer remain after removing the portions of the second hard mask layer (this necessarily occurs at some point during the etch of Figs. 2-3 because layer 230 is firstly exposed to the etch, thus underlying layer 220 must necessarily remain during consumption of overlying layer 230).
Regarding independent claim 15, Wang discloses a method, comprising:
forming a first hard mask layer (Fig. 2: 220) over a substrate (210) of a semiconductor device;
forming a second hard mask layer (230) over the first hard mask layer;
forming sacrificial structures ([0014]: “a patterned resist”) over the second hard mask layer;
performing a first pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed to form a first pattern in the second hard mask layer (the resultant 230 of Fig. 3; [0014]: “etched through the patterned resist”) based on the sacrificial structures,
wherein forming the first pattern removes spacers, over the second hard mask layer, and portions of the second hard mask layer (the “portions” being some of those of Fig. 2: 230 that have been removed in Fig. 3), and
wherein the first pattern comprises a first width (Note: the “first width” is measured along a width direction. See annotated figure for width and direction designation) between portions of the second hard mask layer (between portions of 230 corresponding to 310A/310C);
performing, after performing the first pulsing technique a second pulsing technique in which the high-frequency RF source and the low-frequency RF source are pulsed to form a second pattern in the first hard mask layer (the resultant 220 of Fig. 3; [0014]: “etched through the patterned resist”) based on the first pattern in the second hard mask layer,
wherein forming the second pattern removes mandrels, over the second hard mask layer, and portions of the first hard mask layer (The “portions” being some of those of Fig. 2: 220 that have been removed in Fig. 3),
wherein the second pattern comprises a second width (Note: the “second width” is measured along the same width direction. See annotated figure) between portions of the first hard mask layer (between portions of 220 corresponding to 310A/310C), wherein the second width is greater than the first width;
etching the substrate based on the first pattern and the second pattern to form a plurality of fin structures for the semiconductor device (Fig. 3: 310, annotated as 310A-310C; [0014]: “etched…to form fins”); and
forming shallow trench isolation (STI) regions (Fig. 4: 320) between the plurality of fin structures.
Wang fails to teach the method including
“wherein forming the first pattern removes spacers, over the second hard mask layer, and portions of the second hard mask layer, and
[…]
wherein forming the second pattern removes mandrels, over the second hard mask layer, and portions of the first hard mask layer,”
Juengling discloses a method
wherein forming the first pattern (Fig. 7: resultant 211) removes spacers (216), over the second hard mask layer (intermediate 211 of Fig. 2), and portions of the second hard mask layer (The conclusion of all relevant steps pertaining to forming 211 is shown in Fig. 8, where the spacers 216 are not included in the resultant structure. Therefore, the spacers are removed. Portions of intermediate 211 have been removed before reaching the conclusion of the forming of the resultant 211 shown in Fig. 7);
[…]
wherein forming the second pattern (resultant 210) removes mandrels, over the second hard mask layer, and portions of the first hard mask layer (The conclusion of all relevant steps pertaining to forming 210 is shown in Fig. 8, where the mandrels 212 and portions of 211 are not included in the resultant structure. Therefore, the mandrels/portions are removed.).
Modifying the method of forming the first and second patterns of Wang by including the method steps of Juengling would arrive at the claimed mandrels and spacers method configuration. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation the resultant first and second patterns perform the function of a mask (Wang: Fig. 3; Juengling: Fig. 7). Juengling provides a teaching to motivate one of ordinary skill in the art before the effective filing date to modify the method in that it would enable a simplified manufacturing process, thereby enhancing manufacturing efficiency ([0082]: “advantageously enable the forming of…devices…with a single mask”). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have the claimed mandrels and spacers method configuration because it would enhance manufacturing efficiency. MPEP 2143 (I)(G).
Wang in view of Juengling fails to teach
“performing a first pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed to form a first pattern in the second hard mask layer […]
[…]
performing, after performing the first pulsing technique a second pulsing technique in which the high-frequency RF source and the low-frequency RF source are pulsed to form a second pattern in the first hard mask layer […]”.
Zhao discloses a method performing a [pulsing technique] ([0121]: “Pulsed plasma processes”) in which a high-frequency radio frequency (RF) source ([0121]: f1; Fig. 10A) and a low-frequency RF source ([0121]: f2; Fig. 10A) are pulsed (as shown in Fig. 10B) to form a [pattern in a layer] ([0121]: “for forming gate structures, spacer structures, self-aligned contact structures, and the like”).
Modifying the method of Wang in view of Juengling by including the pulsing technique disclosed by Zhao when forming the first pattern and when forming the second pattern would arrive at the claimed pattern forming method configuration, i.e., first and second pulsing techniques. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used (Wang: [0014]: “a biased plasma etching process”; Zhao: [0121]: “Pulsed plasma processes”). Zhao provides a teaching to motivate one of ordinary skill in the art before the effective filing date to modify the method in that it would improve manufacturing control when forming a pattern, thereby improving manufacturing resilience ([0123]: “precise RF power control”). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have the claimed pulsing technique because it would improve manufacturing resilience. MPEP 2143 (I)(G).
Wang in view of Juengling and Zhao teaches the first and second widths but fails to teach the claimed configuration:
“wherein the first pattern comprises a first width between portions of the second hard mask layer;
[…]
wherein the second pattern comprises a second width between portions of the first hard mask layer, wherein the second width is greater than the first width;”
However, as cited above, Zhao teaches using a plasma-based etch tool (citation repeated here, [0121]: “plasma processing apparatus”).
Tsai discloses using a plasma-based etch tool ([0033]: “plasmas”) when forming a first pattern in the second hard mask layer (Fig. 9: pattern 214), and a second pattern in the first hard mask layer (pattern 212),
wherein the first pattern comprises a first width (See annotated figure for Width direction) between portions of the second hard mask layer (between portions of 214 corresponding to neighboring 902);
[…]
wherein the second pattern comprises a second width (See annotated figure for Width direction) between portions of the first hard mask layer (between portions of 212 corresponding to neighboring 902), wherein the second width is greater than the first width ([0032]: “relatively larger tapering profile” indicates at least some amount of tapering exists in all disclosed hard mask layers; tapering is shown for 214/212 in region 204);
It would have been obvious to one having ordinary skill in the art before the effective filing date to have the claimed first and second width configuration because it is a resultant width configuration produced by a plasma-based etch tool. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used on a mask (Wang: [0014]: “a biased plasma etching process”; Tsai: [0033]: “plasmas”). Tsai provides a teaching to motivate one of ordinary skill in the art before the effective filing date to include the claimed width configuration because it would enable enhanced control over resultant device sizes, thereby improving manufacturing capabilities ([0012]: “maintained the same width, leading to…enlarged process window”). Therefore, the claim would have been obvious to one of ordinary skill in the art before the effective filing date because it would enable improved manufacturing capabilities. MPEP 2143 (I)(G).
Regarding claim 16, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 15 (Wang: Fig. 3), wherein performing the second pulsing technique comprises: performing the second pulsing technique in a first etch operation to etch a first portion of the first hard mask layer (the first etch operation is the commencement of etching of the otherwise unetched intermediate 220 of Fig. 2; the “first portion” is the initially exposed surface of intermediate 220 subject to this etching); and performing the second pulsing technique in a second etch operation after the first etch operation to etch a second portion of the first hard mask layer (the second etch operation is the completion of etching of 220 of Fig. 3, the “second portion” is the finally exposed surface of resultant 220 subject to this etching).
Regarding claim 17, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 15 (Zhao: Fig. 10B), wherein the high-frequency RF source and the low-frequency RF source are pulsed (portions A and C, respectively, See annotated figure) such that a starting time for an on-and-off duration for the low-frequency RF source (start of portion C) occurs after an offset time duration (duration of portions A+B) from a starting time of an on-and- off duration for the high-frequency RF source (start of portion A).
Regarding claim 18, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 17 (Zhao: Fig. 10B), wherein the offset time duration comprises […] % of the on-and-off duration for the low-frequency RF source (portions A+B, of on-and-off duration A+B+C+D).
Wang in view of Juengling, Zhao, and Tsai fails to explicitly teach “the offset time duration comprises approximately 30% to approximately 80% of the on-and-off duration for the low-frequency RF source”. However, Zhao discloses on durations within on-and-off durations may be varied within the disclosed embodiments of the method. More specifically, Zhao discloses:
First and second on durations use a pulsing technique (as cited in the claim 15 rejection, [0121]: “Pulsed plasma processes”).
The pulsing technique is controlled by a controller ([0121]: “dual channel versions are realized by either using two single channel units in parallel or by duplicating the single channel version in one integrated unit”).
A controller in which a RF source may be pulsed operates within an on-and-off duration ([0046]: “any value between and including zero and 100%”).
Additionally, and with respect to the selected embodiment (the selected embodiment being the embodiment of Fig. 10B): because Zhao discloses the controllers of first and second on durations (occurring respectively within on-and-off durations for high- and low-frequency RF sources) as two separate controllers (as cited above); and does not disclose the controllers of the selected embodiment requiring any particular relation therebetween with respect to on-and-off durations, on durations therein, or offset time durations therebetween; it is reasonable to separately apply the known suitable on duration range of the controller disclosed in [0046].
A non-exhaustive, exemplary selection of values within the disclosed first and second on durations produces conditions falling squarely within the claimed offset time duration range. The selected values are as follows:
Selecting 30% for the first on duration (portion A).
Selecting 20% for the second on duration (portion C).
The offset time duration (A+B) must be equal to or greater than the first on duration (A, 30%) and equal to or less than the remainder of the on-and-off duration of the second source (A+B+D, 80%), therefore within 30-80% and encompassing the claimed range.
However, differences in offset time duration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such duration is critical. “[W]here the general conditions of the claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). MPEP 2144.05 (II)(A).
Since the applicant has not established the criticality (see next paragraph) of “the offset time duration comprises approximately 30% to approximately 80% of an on-and-off duration in which the on duration of the first on durations occurs”, 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 offset time duration as described by Zhao in the combination of Wang, Juengling, Zhao, and Tsai to obtain optimized results through routine experimentation. MPEP 2144.05 (II)(A).
The specification contains no disclosure of either the critical nature of the claimed offset time duration or any unexpected results arising therefrom. Where patentability is said to be based upon particular chosen dimensions or upon another variable recited in a claim, the applicant must show that the particular range is critical. In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990). MPEP 2144.05 (III)(A).
Regarding claim 20, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 15 (Zhao: Fig. 10A), wherein the high-frequency RF source is pulsed at a first frequency (
1
A
+
B
+
C
+
D
); wherein the low-frequency RF source is pulsed at a second frequency (
1
A
+
B
+
C
+
D
); and wherein the first frequency and the second frequency are each included in a range of approximately 50 hertz to approximately 1000 hertz (Fig. 10B shows the high- and low-frequency RF sources do not have overlapping pulses, therefore the first and second frequency are matched; [0039]: “about 1 Hz to about wo kHz” appears to have a typographical error, where “wo” may reasonably be interpreted as “two”, and this disclosed range completely encompasses the claimed range).
Claim 26 is rejected under 35 U.S.C. 103 as being obvious over Wang, Juengling, Zhao, and Tsai, and further in view of Lin (US 20230068794 A1).
The applied reference has a common inventor with the instant application. Based upon the earlier effectively filed date of the reference, it constitutes prior art under 35 U.S.C. 102(a)(2).
This rejection under 35 U.S.C. 103 might be overcome by: (1) a showing under 37 CFR 1.130(a) that the subject matter disclosed in the reference was obtained directly or indirectly from the inventor or a joint inventor of this application and is thus not prior art in accordance with 35 U.S.C.102(b)(2)(A); (2) a showing under 37 CFR 1.130(b) of a prior public disclosure under 35 U.S.C. 102(b)(2)(B); or (3) a statement pursuant to 35 U.S.C. 102(b)(2)(C) establishing that, not later than the effective filing date of the claimed invention, the subject matter disclosed and the claimed invention were either owned by the same person or subject to an obligation of assignment to the same person or subject to a joint research agreement. See generally MPEP § 717.02.
Regarding claim 26, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 25, but fails to teach the method “further comprising: forming a pad oxide layer over the substrate, wherein the plurality of hard mask layers resides over the pad oxide layer, and wherein the pad oxide layer remains after removing the portions of the second hard mask layer.”
Lin discloses a method, further comprising:
forming a pad oxide layer (Fig. 12: 120; [0018]: “pad oxide layer”) over the substrate (110), wherein the plurality of hard mask layers (130, 140) resides over the pad oxide layer, and
wherein the pad oxide layer remains (Fig. 15) after removing the portions of the second hard mask layer.
Modifying the method of Wang, Juengling, Zhao, and Tsai by forming a pad oxide layer consistent with the teachings of Lin would arrive at the claimed method and pad oxide configuration. A person of ordinary skill in the art before the effective filing date would have had a reasonable expectation of success doing so because in each situation a mask is used to form a fin (Wang: Fig. 3; Lin: Fig. 16B: mask M1´ and fin 112). Lin provides a teaching to motivate one of ordinary skill in the art before the effective filing date to include forming a pad oxide layer in the method in that it would enable adjusting the etch selectivity during the manufacturing process ([0016]: “to achieve desired etching selectivity”), thereby enhancing manufacturing capability. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have the claimed method and pad oxide configuration because it would enable adjusting the etch selectivity during the manufacturing process. MPEP 2143 (I)(G).
Claims 8-10, 12-14, and 22 are rejected under 35 U.S.C. 103 as being obvious over Lin in view of Zhao and Tsai.
The applied reference (Lin) has a common inventor with the instant application. Based upon the earlier effectively filed date of the reference, it constitutes prior art under 35 U.S.C. 102(a)(2).
This rejection under 35 U.S.C. 103 might be overcome by: (1) a showing under 37 CFR 1.130(a) that the subject matter disclosed in the reference was obtained directly or indirectly from the inventor or a joint inventor of this application and is thus not prior art in accordance with 35 U.S.C.102(b)(2)(A); (2) a showing under 37 CFR 1.130(b) of a prior public disclosure under 35 U.S.C. 102(b)(2)(B); or (3) a statement pursuant to 35 U.S.C. 102(b)(2)(C) establishing that, not later than the effective filing date of the claimed invention, the subject matter disclosed and the claimed invention were either owned by the same person or subject to an obligation of assignment to the same person or subject to a joint research agreement. See generally MPEP § 717.02.
Regarding independent claim 8, Lin discloses a method, comprising:
forming a first hard mask layer (Fig. 12: 130) over a substrate (110) of a semiconductor device ([0015]: “a semiconductor substrate”);
forming a second hard mask layer (140) over the first hard mask layer;
forming mandrels (M2) and spacers (220) over the second hard mask layer;
forming a first pattern in the second hard mask layer (Figs. 13-14), based on the mandrels and the spacers, to remove the spacers (spacers 220 are removed in Figs. 13-14) and first portions of the second hard mask layer (portions of 140 are removed in Figs. 13-14) such that second portions of the second hard mask layer (142) remain over the first hard mask layer, wherein the first hard mask layer remains between the second portions of the second hard mask layer (all of 130 is remaining in Fig. 14), and wherein a first width between the mandrels is greater than a second width between the second portions of the second hard mask layer;
performing, after forming the first pattern, a pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed in an alternating manner to form a second pattern (Fig. 15: 132) in the first hard mask layer, based on the mandrels and the first pattern, to remove the mandrels and first portions of the first hard mask layer (mandrels M2 are removed at Fig. 15 when forming pattern 132) such that second portions of the first hard mask layer remain over the substrate, wherein a third width between the second portions of the first hard mask layer is greater than the second width between the second portions of the second hard mask layer;
etching the substrate (Fig. 16B) based on the first pattern and the second pattern to form a plurality of fin structures (112) for the semiconductor device; and
forming a gate structure (Fig. 17B: 250) over the plurality of fin structures.
Lin fails to teach
“performing, after forming the first pattern, a pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed in an alternating manner to form a second pattern (Fig. 15: 132) in the first hard mask layer, […]”
Zhao discloses a method performing a pulsing technique ([0121]: “Pulsed plasma processes”) in which a high-frequency radio frequency (RF) source ([0121]: f1; Fig. 10A) and a low-frequency RF source ([0121]: f2; Fig. 10A) are pulsed in an alternating manner (as shown in Fig. 10B) to form a [pattern in a layer] ([0121]: “for forming gate structures, spacer structures, self-aligned contact structures, and the like”).
Modifying the method of Lin by including the pulsing technique disclosed by Zhao when patterning at least the first hard mask layer would arrive at the claimed pattern forming method configuration. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used (Lin: [0043]: “plasma”; Zhao: [0121]: “Pulsed plasma processes”). Zhao provides a teaching to motivate one of ordinary skill in the art before the effective filing date to modify the method in that it would improve manufacturing control when forming a pattern, thereby improving manufacturing resilience ([0123]: “precise RF power control”). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to have the claimed pulsing technique because it would improve manufacturing resilience. MPEP 2143 (I)(G).
Lin in view of Zhao teaches the first, second, and third widths but fails to teach the claimed configuration:
“forming a first pattern in the second hard mask layer, based on the mandrels and the spacers, to remove the spacers and first portions of the second hard mask layer such that second portions of the second hard mask layer remain over the first hard mask layer, wherein the first hard mask layer remains between the second portions of the second hard mask layer, and wherein a first width between the mandrels is greater than a second width between the second portions of the second hard mask layer;
performing, after forming the first pattern, a pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed in an alternating manner to form a second pattern in the first hard mask layer, based on the mandrels and the first pattern, to remove the mandrels and first portions of the first hard mask layer such that second portions of the first hard mask layer remain over the substrate, wherein a third width between the second portions of the first hard mask layer is greater than the second width between the second portions of the second hard mask layer;”
However, as cited above, Zhao teaches using a plasma-based etch tool (citation repeated here, [0121]: “plasma processing apparatus”).
Tsai discloses using a plasma-based etch tool ([0033]: “plasmas”) when
forming a first pattern in the second hard mask layer (Fig. 7: pattern 214), based on the mandrels (within 402) and the spacers (402), to remove the spacers and first portions of the second hard mask layer (removal is shown progressing from Fig. 6 to Fig. 7) such that second portions of the second hard mask layer remain over the first hard mask layer (the remainder of 214 is shown in Fig. 7), wherein the first hard mask layer remains between the second portions of the second hard mask layer (between neighboring portions of 214), and wherein a first width between the mandrels is greater than a second width between the second portions of the second hard mask layer (“greater” because of tapering; [0032]: “relatively larger tapering profile” indicates at least some amount of tapering exists in all disclosed hard mask layers; tapering is shown for 214/212 in region 206);
performing, after forming the first pattern, a pulsing technique in which a high-frequency radio frequency (RF) source and a low-frequency RF source are pulsed in an alternating manner to form a second pattern in the first hard mask layer (pattern 212), based on the mandrels and the first pattern, to remove the mandrels and first portions of the first hard mask layer (removal is shown progressing from Fig. 6 to Fig. 7) such that second portions of the first hard mask layer remain over the substrate, wherein a third width between the second portions of the first hard mask layer is greater than the second width between the second portions of the second hard mask layer (“greater” because of tapering; [0032]: “relatively larger tapering profile” indicates at least some amount of tapering exists in all disclosed hard mask layers; tapering is shown for 214/212 in region 206);”
It would have been obvious to one having ordinary skill in the art before the effective filing date to have the claimed first, second, and third width configuration because it is a resultant width configuration produced by a plasma-based etch tool. A person of ordinary skill in the art before the effective filing date would have a reasonable expectation of success because in each situation a plasma-based etch tool is used on a mask (Lin: [0043]: “plasma”; Tsai: [0033]: “plasmas”). Tsai provides a teaching to motivate one of ordinary skill in the art before the effective filing date to include the claimed width configuration because it would enable enhanced control over resultant device sizes, thereby improving manufacturing capabilities ([0012]: “maintained the same width, leading to…enlarged process window”). Therefore, the claim would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention because it would enable improved manufacturing capabilities. MPEP 2143 (I)(G).
Illustrated below is a marked and annotated figure of Fig. 7 of Tsai.
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Regarding claim 9, Lin in view of Zhao and Tsai discloses the method of claim 8 (Zhao: Fig. 10B), wherein the high-frequency RF source and the low-frequency RF source are pulsed such that on durations for the high-frequency RF source (A, See annotated figure) occur during off durations for the low-frequency RF source (A+B+D); and wherein the high-frequency RF source and the low-frequency RF source are pulsed such that on durations for the low-frequency RF source (C) occur during off durations for the high- frequency RF source (B+C+D).
Regarding claim 10, Lin in view of Zhao and Tsai discloses the method of claim 8 (Lin: Fig. 12), wherein the first hard mask layer comprises a silicon nitride (SixNy) material ([0017]: “silicon nitride”); and wherein the second hard mask layer comprises a silicon oxide (SiOx) material ([0017]: “silicon oxide”).
Regarding claim 12, Lin in view of Zhao and Tsai discloses the method of claim 8 (Zhao: Fig. 10B), wherein the high-frequency RF source is pulsed at a first frequency (
1
A
+
B
+
C
+
D
); wherein the low-frequency RF source is pulsed at a second frequency (
1
A
+
B
+
C
+
D
); and wherein the first frequency and the second frequency are each included in a range of approximately 50 hertz to approximately 1000 hertz (Fig. 10B shows the high- and low-frequency RF sources do not have overlapping pulses, therefore the first and second frequency are matched; [0039]: “about 1 Hz to about wo kHz” appears to have a typographical error, where “wo” may reasonably be interpreted as “two”, and this disclosed range completely encompasses the claimed range).
Regarding claim 13, Lin in view of Zhao and Tsai discloses the method of claim 8 (Lin: Fig. 12), wherein a height of the second hard mask layer after the second pattern is formed in the first hard mask layer is in a range of approximately 40 nanometers to approximately 50 nanometers (a dimensional feature of the resultant 230 illustrated in Fig. 3).
Lin as applied in the combination of Lin, Zhao, and Tsai fails to explicitly teach the range for the height at the claimed moment in the method being “a height of the second hard mask layer after the second pattern is formed in the first hard mask layer is in a range of approximately 40 nanometers to approximately 50 nanometers”. However, Lin establishes a scale for other structures related to the second hard mask layer ([0035]: “greater than 15 nanometers…less than about 5 nanometers” is a scale on the order of tens of nanometers; Fig. 10: structure 220), and this scale may reasonably be applied to the height of the second hard mask layer because in each situation the layer is performing the function of forming a mask (Fig. 12: layer 220 is used when forming mask 142; Fig. 14: layer 140/142 is used when forming mask 132). Thus, Lin establishes a scale for the height of the second hard mask layer that is reasonably close to the claimed height (i.e., on the order of tens of nanometers). Therefore, the claimed height would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to, since a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). MPEP 2144.05 (I).
Regarding claim 14, Lin in view of Zhao and Tsai discloses the method of claim 8 (Zhao: Fig. 10B), wherein the high-frequency RF source and the low-frequency RF source are pulsed in the alternating manner to control a ratio of ions to radicals while etching the first hard mask layer to form the second pattern (as cited in the claim 8 rejection, Zhao teaches two different frequencies f1 and f1 are selected and pulsed; Zhao also teaches frequency selection is a result effective variable for effecting the etching characteristics; [0065]: “ion flux to radical flux ratio…are frequency dependent…anisotropy”. Note: by selecting the frequencies it would necessarily control the ratio while etching).
Regarding claim 22, Lin in view of Zhao and Tsai discloses the method of claim 8 (Zhao: Fig. 10B), wherein the forming of the second pattern reduces a height of the first pattern ([0133]: “isotropically etching” necessarily etches in all directions including a height direction, therefore the isotropic pulsing technique of Zhao reduces a height).
Allowable Subject Matter
Claims 8-10, 12-14, and 22 are allowed.
The following is a statement of reasons for the indication of allowable subject matter:
The primary reason for the allowable subject matter of claims 8-10, 12-14, and 22 is the inclusion of the limitation “” in combination with the other limitations in the claim. For example, prior art of record fails to teach or be reasonably combined to render obvious the claimed limitations “abc”, “def”, and “xyz” in combination with all other limitations in claim 8.
Response to Arguments
Applicant's arguments filed 4/30/2026 have been fully considered but they are not persuasive.
Applicant argues:
Applicant argues with respect to amended claims 1 and 15 that “the cited sections of the applied references, whether taken alone or in any reasonable combination, do not disclose at least…wherein the first pattern comprises a first width between portions of the second hard mask layer, and wherein the second pattern comprises a second width between portions of the first hard mask layer, wherein the second width is greater than the first width," as recited in claim 1, as amended”. Remarks at pg. 10.
Examiner’s reply:
The examiner finds Applicant’s remarks consistent with Proposal #2 of the 4/16/2026 interview and directed to an embodiment disclosed in Fig. 3K. However, the claim as written appears to be directed to a configuration of this embodiment different from the illustrated embodiment because:
Fig. 3K shows the first width W3 is greater than the second width W4.
Claims 1 and 15 are written in a way where “width between” could reasonably refer to solid structures between other solid structures, and be directed to an alternative configuration disclosed in [0075]: “Alternatively, the width (W4) is greater relative to the width (W3)”; or alternatively “width between” could reasonably refer to negative space between solid structures, and be mapped to the embodiment illustrated in Fig. 3K.
Accordingly, the examiner finds the claim as written similar to the configuration rendered obvious in the Office action mailed 2/13/2026. Claims 1 and 15 are rejected in the instant Office action using the same references as before in the same way.
Applicant argues:
Applicant argues with respect to amended claim 8 that “the cited sections of the applied references, whether taken alone or in any reasonable combination, do not disclose at least […] as recited in claim 8, as amended”. Remarks at pg. 11.
Examiner’s reply:
Applicant’s arguments with respect to claim(s) 8 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. The amendments to the claim clarify when each of the structures are consumed during the method in such a way to distinguish the claimed invention from the contended references as previously applied. However, a new reference (Lin) is relied upon in the instant Office action as necessitated by the claim amendment.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Lin (CN 113363209 A) discloses a method, further comprising:
forming a pad oxide layer (Fig. 10: 11) over the substrate (10), wherein the plurality of hard mask layers (12, 13) resides over the pad oxide layer, and
wherein the pad oxide layer remains (Fig. 12) after removing the portions of the second hard mask layer.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WILLIAM H ANDERSON whose telephone number is (571)272-2534. The examiner can normally be reached Monday-Friday, 8:00-5:00.
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/WILLIAM H ANDERSON/ Examiner, Art Unit 2817
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