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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/5/2025 has been entered.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-6, 8-9, 12-18, 20-22, and 24 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); […]
performing, using a plasma-based etch tool ([0014]: “a biased plasma etching process”), […] to form a first pattern in the second hard mask layer (the resultant 230 of Fig. 3; [0014]: “etched through the patterned resist”) having a first width (Note: the “first width” is measured along a width direction. See annotated figure for width and direction designation), and a second pattern in the first hard mask layer having a second width (the resultant 220 of Fig. 3; [0014]: “etched through the patterned resist”; Note: the “second width” is measured along the same width direction. See annotated figure) […],
wherein the forming of the first pattern removes […] 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”), and
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) […];
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 (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 “forming mandrels and spacers over the plurality of hard mask layers;
[…] to form a first pattern in the second hard mask layer having a first width, and a second pattern in the first hard mask layer having a second width […], 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, and
wherein the forming of the second pattern is after the forming of the first pattern and removes the mandrels”.
Juengling discloses a method forming mandrels (Fig. 7: 212) and spacers (216) […] to form a first pattern in the second hard mask layer (resultant 211) having a first width, and a second pattern in the first hard mask layer (resultant 210) having a second width […], 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), and
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.).
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 Fig. of Juengling.
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Wang in view of Juengling teaches the plasma-based etch tool 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).
Wang in view of Juengling and Zhao teaches the first and second widths but fails to teach “a first pattern in the second hard mask layer having a first width, and a second pattern in the first hard mask layer having a second width greater than the first width”.
Tsai discloses using a plasma-based etch tool ([0033]: “plasmas”) when forming a first pattern in the second hard mask layer having a first width (Fig. 9: pattern 214), and a second pattern in the first hard mask layer (pattern 212) having a second width 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 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.).
Regarding claim 4, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 3, and teaches the offset time duration comprises […] % of an on-and-off duration (Zhao: portions A+B, See annotated Fig. 10B below) in which the on duration of the first on durations occurs (portions 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 an on-and-off duration in which the on duration of the first on durations occurs”. However, Zhao discloses on durations may be varied within the disclosed embodiments of the method. More specifically, Zhao discloses:
The first and second on durations use a pulsing technique (as cited in the claim 1 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 is the embodiment of Fig. 10B); since Zhao discloses the controllers of the first and second on durations as two separate controllers (as cited in the bullets above), and does not disclose the controllers of the selected embodiment requiring any particular relation between each other with respect to on duration, 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 thus 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 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).
Illustrated below is a marked and annotated figure of Figs. 10A-10C of Zhao.
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Regarding claim 5, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 2 (Zhao: Fig. 10B), wherein a duty cycle of the second on durations (portion C relative to A+B+C+D) is […] relative to a duty cycle of the first on durations (portion A relative to A+B+C+D).
Wang in view of Juengling, Zhao, and Tsai fails to explicitly teach “a duty cycle of the second on durations is greater relative to a duty cycle of the first on durations”. However, Zhao discloses on durations and therefore duty cycles may be varied within the disclosed embodiments of the method. More specifically, Zhao discloses:
The first and second on durations use a pulsing technique (as cited in the claim 1 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 a duty cycle ([0046]: “any value between and including zero and 100%”).
Additionally, and with respect to the selected embodiment (the selected embodiment is the embodiment of Fig. 10B); because Zhao discloses the controllers of the first and second on durations 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 duration, 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 duty cycle relation. The selected values are as follows:
Selecting 30% for the first on duration, i.e., a duty cycle of the first on durations (portion A).
Selecting 31% for the second on duration, i.e., a duty cycle of the second on durations (portion C), therefore greater than 30% and encompassing the claimed relation.
However, differences in duty cycle will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such duty cycle 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).
Since the applicant has not established the criticality (see next paragraph) of “a duty cycle of the second on durations is greater relative to a duty cycle of the first on durations”, it would have been obvious to one of ordinary skill in the art before the effective filing date to modify the duty cycles as described by Zhao in the combination of Wang, Juengling, Zhao, and Tsai to obtain optimized results through routine experimentation.
The specification contains no disclosure of either the critical nature of the claimed duty cycles 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 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 has parallel sides (parallel top/bottom sides. See annotated figure for side designation).
Regarding independent claim 8, 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 a first pattern in the second hard mask layer (the resultant 230 of Fig. 3; [0014]: “etched through the patterned resist”) having a first width (Note: the “first width” is measured along a width direction. See annotated figure for width and direction designation) […], wherein the forming of the first pattern removes […] portions of the second hard mask layer (the “portions” being some of those of Fig. 2: 230 that have been removed in Fig. 3);
performing, after forming the first pattern, […] form a second pattern in the first hard mask layer (the resultant 220 of Fig. 3; [0014]: “etched through the patterned resist”) having a second width (Note: the “second width” is measured along a width direction. See annotated figure for width and direction designation) […] based on […] the first pattern, wherein the forming of the second pattern removes […] portions of the first hard mask layer (The “portions” being some of those of Fig. 2: 220 that have been removed in Fig. 3);
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 a gate structure over the plurality of fin structures ([0028]: “gate…stacks are formed over…the fins”).
Wang fails to teach “forming mandrels and spacers over the second hard mask layer;
forming a first pattern in the second hard mask layer having a first width based on the mandrels and the spacers, wherein the forming of the first pattern removes the spacers and portions of the second hard mask layer;
[…] form a second pattern in the first hard mask layer having a second width […] based on the mandrels and the first pattern, wherein the forming of the second pattern removes the mandrels and portions of the first hard mask layer”.
Juengling discloses a method forming mandrels (Fig. 7: 212) and spacers (216) over the second hard mask layer (211);
forming a first pattern in the second hard mask layer (resultant 211) having a first width 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 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);
[…] form a second pattern in the first hard mask layer (resultant 210) having a second width […] based on the mandrels and the first pattern (Fig. 7 shows the resultant shapes of 210 corresponds to the shape of mandrels/spacers/pattern 212/216/211, thus “based on”), wherein the forming of the second pattern removes the mandrels 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, 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”.
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 Wang in view of Juengling 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 (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 “a first pattern in the second hard mask layer having a first width […] a second pattern in the first hard mask layer having a second width 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 having a first width (Fig. 9: pattern 214), and a second pattern in the first hard mask layer (pattern 212) having a second width 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 of the claimed invention because it would enable improved manufacturing capabilities. MPEP 2143 (I)(G).
Regarding claim 9, Wang in view of Juengling, 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 12, Wang in view of Juengling, 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
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+
B
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C
+
D
); wherein the low-frequency RF source is pulsed at a second frequency (
1
A
+
B
+
C
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); 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, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 8 (Wang: Fig. 3), 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 […] (a dimensional feature of the resultant 230 illustrated in Fig. 3).
Wang as applied in the combination of Wang, Juengling, Zhao, and Tsai fails to explicitly teach the range for the height 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, Wang discloses the second hard mask layer includes silicon nitride used as a hard mask ([0013]: “hard mask…silicon nitride”).
Juengling discloses silicon nitride used as a hard mask ([0050]: “silicon nitride”, [0058]: “deep trenches 400 are separated by remaining portions of the nitride layer 211”), discloses a range for a height thereof ([0050]: “between about 20 Å and 2000 Å”, completely encompassing the claimed range), the height being preserved after the second pattern is formed in a first hard mask layer (as shown in Fig. 7).
It would have been obvious to one of ordinary skill in the art before the effective filing date to substitute the height of Juengling in place of the comparable known height of Wang, and the results would have been predictable, because the height (of both Wang and Juengling) would have functioned the same as before as a silicon nitride used as a hard mask. Therefore, having “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” would have been obvious to one of ordinary skill in the art before the effective filing date because this known height would have obtained predictable results. MPEP 2143 (I)(B).
Regarding claim 14, Wang in view of Juengling, 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, Wang in view of Juengling, 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).
Regarding independent claim 15, Wang discloses a method, comprising:
forming a first hard mask layer (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;
[…] form a first pattern in the second hard mask layer (the resultant 230 of Fig. 3; [0014]: “etched through the patterned resist”) having a first width (Note: the “first width” is measured along a width direction. See annotated figure for width and direction designation) based on the sacrificial structures,
wherein forming the first pattern removes […] portions of the second hard mask layer (the “portions” being some of those of Fig. 2: 230 that have been removed in Fig. 3);
[…] form a second pattern in the first hard mask layer (the resultant 220 of Fig. 3; [0014]: “etched through the patterned resist”) having a second width (Note: the “second width” is measured along a width direction. See annotated figure for width and direction designation) […] based on the first pattern in the second hard mask layer,
wherein forming the second pattern removes […] portions of the first hard mask layer (The “portions” being some of those of Fig. 2: 220 that have been removed in Fig. 3);
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 “wherein forming the first pattern removes spacers, over the second hard mask layer, and portions of 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”.
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” and “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 “a first pattern in the second hard mask layer having a first width […] a second pattern in the first hard mask layer having a second width 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 having a first width (Fig. 9: pattern 214), and a second pattern in the first hard mask layer (pattern 212) having a second width 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 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 10 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, Juengling, Zhao, and Tsai as applied to claim 8 above, and further in view of Wang (US 20190385902 A1, hereinafter Wang ‘902).
Regarding claim 10, Wang in view of Juengling, Zhao, and Tsai discloses the method of claim 8 (Wang: Fig. 2), but fails to teach the claimed material configuration of the first and second hard mask layer or a rearrangement thereof “wherein the first hard mask layer comprises a silicon nitride (SixNy) material; and wherein the second hard mask layer comprises a silicon oxide (SiOx) material.”
Wang ‘902 discloses a method with a first hard mask layer (Fig. 11: 108) and second hard mask layer (110) configuration, wherein the first hard mask layer comprises a silicon nitride (SixNy) material ([0016]: “silicon nitride”); and wherein the second hard mask layer comprises a silicon oxide (SiOx) material ([0017]: “silicon oxide”). Additionally, Wang ‘902 teaches: the particular material compositions for the first and second hard mask layers may each be varied as a design choice ([0016] discloses a finite selection of known suitable materials for the first hard mask layer; and [0018] discloses a finite selection of known suitable materials for the second hard mask layer); material composition may be differ between the first and second hard mask layers (by disclosing separate and different selections of known suitable materials in [0016] and [0017]); and material composition may be selected to effect the resultant etching characteristics of the method ([0016]: “material composition…to provide a high etch selectivity”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the material composition configuration of Wang ‘902 in place of the comparable known material composition configuration, and the results would have been predictable, because:
Wang teaches: the first hard mask layer and the second hard mask layer” collectively comprises a silicon nitride (SixNy) material ([0013]: “silicon nitride” with respect to the second hard mask layer 230) and a silicon oxide (SiOx) material ([0013]: “silicon oxide” with respect to the first hard mask layer 220); and the particular material compositions for the first and second hard mask layers may each be varied as a design choice ([0013]: “other suitable material” and [0013]: “any suitable materials”, respectively). Additionally, Wang teaches material composition may be differ between the first and second hard mask layers ([0013]: “The HM layer 230 is different from the first dielectric layer 220”) and may be selected to effect the resultant etching characteristics of the method (“to achieve etching selectivity during a subsequent etch” [0013]). Thus, the particular material composition of the first and second hard mask layers does not appear critical to the function thereof and may be varied as a design choice to effect the resultant etching characteristics of the method.
And the compositions would have functioned the same in each situation (Wang, Wang ‘902) as first and second hard mask layers selected to effect the resultant etching characteristics of the method.
Therefore, having “wherein the first hard mask layer comprises a silicon nitride (SixNy) material; and wherein the second hard mask layer comprises a silicon oxide (SiOx) material” would have been obvious to one of ordinary skill in the art before the effective filing date because this known material configuration would have obtained predictable results in a similar situation. MPEP 2143 (I)(B).
Response to Arguments
Applicant's arguments filed 12/5/2025 have been fully considered but they are not persuasive.
Applicant argues with respect to claim 1 that “amended claim 1, and claims 2-6 and 21 dependent thereon, satisfy the written description requirement” and “claims 1 and 15, and the claims dependent thereon, are definite”. Remarks at pg. 9.
Examiner’s reply:
The examiner agrees and finds claim 1 as presently written reading on the specific embodiment of [0069]-[0070] of Applicant’s disclosure where forming the first pattern in the second hard mask layer includes may be combined with additional etches effectively creating an over-etch into the first hard mask layer ([0070]: “a first etch operation to etch a first portion of the first hard mask layer”).
Applicant argues:
Applicant argues with respect to claim 1 that “a width of TSAI's pattern 212 is less than a width of pattern 214. Accordingly, TSAI does not disclose “a first pattern ... having a first width, and a second pattern ... having a second width greater than the first width,” as required by amended claim 1”. Remarks at pg. 2.
Examiner's reply:
Applicants remarks regarding the claimed width configuration is not persuasive. The examiner is relying upon Wang to teach: the first hard mask layer (220, a lower layer) with a second pattern having a second width (the resultant width of lower layer 220); and the second hard mask layer (230, an upper layer) with a first pattern having a first width (the resultant width of upper layer 230). The examiner’s assignment of “first” and “second” to the layers, patterns, and widths is consistent with Applicant’s assignment which appears to relate to the sequence of manufacture and not to a direction/spatial configuration.
The examiner has relied upon Tsai to teach a modification to the method, with this modification including a difference in width (Tsai: Fig. 9: the width of lower layer 212 is greater than the width of upper layer 214). This difference in width matches the claim (the lower width is greater than the upper width). The examiner has mapped the widths of Tsai to Wang by respectively matching the upper and lower layers among these methods (upper layer of Tsai 214 to upper layer of Wang 230, includes a first width; lower layer of Tsai 212 to lower layer of Wang 220, includes a second width). Applicants remarks regarding the widths of Tsai appear to be an inversion of the widths actually shown by the reference. Accordingly, Applicant's remarks regarding the claimed width are not persuasive.
Applicant argues:
Applicant argues with respect to new claim 24 that “claim 24 depends from independent claim 1 and is therefore patentable”. Remarks at pg. 12.
Examiner’s reply:
The examiner finds Applicant’s remarks directed to width embodiments described in [0075] of the disclosure. However, the examiner disagrees and points to MPEP 2111. The claim as written reasonably includes a plurality of surface configurations beyond those explicitly disclosed by Applicant. Accordingly, the claim is rejected in the instant Office action.
Conclusion
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/WILLIAM H ANDERSON/ Examiner, Art Unit 2817