DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of the Claims
This is a final office action in response to the applicant’s arguments and remarks filed on 05/18/2026. Claims 1-17 and 21-25 are pending in the current office action. Claims 1, 10, and 21 have been amended by the applicant and Claims 24-25 are new claims.
Status of the Rejection
The drawing objections have been overcome by the applicant's amendments.
All 35 U.S.C. § 103 rejections from the previous office action are substantially maintained and modified only in response to the amendments to the claims.
Some new grounds of rejection under 35 U.S.C. § 103 are necessitated by the amendments.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Veber et al. (US-20230298896-A1) in view of Dole et al. (US-20190393047-A1) (note: this rejection is being presented as an alternative rejection to the rejection below. The rejection below is the same rejection presented in the previous office action, modified only in response to the amendments. This rejection relies upon an alternative interpretation of the prior art and claim limitations).
Regarding Claim 1, Veber teaches a method of plasma etching a substrate, the method comprising cyclically (Paragraph [0002] teaches a method that includes plasma etching a substrate. Paragraph [0087] the process can be repeated cyclically):
performing a first etch step (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process) to etch a target material, the substrate comprising a patterned mask disposed over the target material and having openings in the patterned mask (Paragraph [0046] Figure 3A substrate (element 300) includes a patterned mask layer (element 302) that includes openings and is over the substrate layer, which is etched), performing the first etch step comprising generating a first plasma from a carbon containing precursor gas (Paragraphs [0049-0052] the first etch generates a first plasma using an etch chemistry that includes fluorocarbons) and exposing the substrate to the first plasma to form a first passivation layer along sidewalls of the patterned mask and vertically etch the target material, the first passivation layer comprising a polymer material (Paragraph [0051] The substrate is etched by exposure to the plasma. Paragraph [0055] the etch process forms a sidewall coating from polymeric material, which may cover the upper portion of the feature, which would comprise the sidewalls that are made of the patterned mask. Paragraph [0046] As seen in Figure 3A and 3B the feature etched includes vertical etching); and
performing a second step, performing the second step comprising generating a second plasma from a tungsten containing precursor gas that is free of fluorocarbons and exposing the substrate to the second plasma (Paragraphs [0066-0067] a second plasma is formed, using a metal-containing gas that can be tungsten hexafluoride. The substrate is exposed to the second plasma to deposit material on the sidewalls. Paragraphs [0067-0070] the gas supplied may or may not contain other components besides tungsten hexafluoride, therefore the gas can be free of fluorocarbons), wherein each cycle of the plasma etching comprises the first etch step and the second step (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process. In an alternative interpretation, in the cyclic etching process taught, the first instance of step 430 could be considered the first instance of the claimed “first etch step” and the following instance of step 420 could be considered the first instance of the claimed “second etch step”).
Veber fails to teach that the second step is an etch step to remove a portion of the first passivation layer. However, Veber teaches that the second process step can utilize some process conditions comparable to the process conditions of an etching process (Paragraph [0064-0065] temperature and pressure in the process is comparable to etch processes). Veber teaches that the process can include breaking apart the tungsten hexafluoride molecule to form radicals which can be reduced to form the tungsten-containing components that form the sidewall deposition material (Paragraph [0068]).
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]). Dole teaches that the plasma-based process utilizing tungsten hexafluoride can result in the formation of tungsten-containing fragments and fluorine-containing fragments, where the fluorine-containing fragments will have an ability to etch a material they are exposed to (Paragraphs [0037-0038]).
Veber is silent on the second step being an etching step that removes a portion of the first passivation layer. However, given that the plasma-based process step based on the disclosure in Veber is substantially similar to the plasma-based process described by Dole, and that in instant claims, it is the examiner's position that the second step described by Veber would inherently have the instantly claimed feature of etching some portion of the first passivation layer. Since PTO cannot conduct experiments the proof of burden is shifted to the applicants to establish a nonobviousness difference. See MPEP 2112. When the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. The Courts have held that it is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. See MPEP 2112.01(I).
Claim 1-17, 21-23, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Veber et al. (US-20230298896-A1) in view of Dole et al. (US-20190393047-A1) and Han et al. (US-20160293445-A1).
Regarding Claim 1, Veber teaches a method of plasma etching a substrate, the method comprising cyclically (Paragraph [0002] teaches a method that includes plasma etching a substrate. Paragraph [0087] the process can be repeated cyclically):
performing a first etch step (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process) to etch a target material, the substrate comprising a patterned mask disposed over the target material and having openings in the patterned mask (Paragraph [0046] Figure 3A substrate (element 300) includes a patterned mask layer (element 302) that includes openings and is over the substrate layer, which is etched), performing the first etch step comprising generating a first plasma from a carbon containing precursor gas (Paragraphs [0049-0052] the first etch generates a first plasma using an etch chemistry that includes fluorocarbons) and exposing the substrate to the first plasma to form a first passivation layer along sidewalls of the patterned mask and vertically etch the target material, the first passivation layer comprising a polymer material (Paragraph [0051] The substrate is etched by exposure to the plasma. Paragraph [0055] the etch process forms a sidewall coating from polymeric material, which may cover the upper portion of the feature, which would comprise the sidewalls that are made of the patterned mask. Paragraph [0046] As seen in Figure 3A and 3B the feature etched includes vertical etching); and
performing a second step, performing the second step comprising generating a second plasma from a tungsten containing precursor gas that is free of fluorocarbons and exposing the substrate to the second plasma (Paragraphs [0066-0067] a second plasma is formed, using a metal-containing gas that can be tungsten hexafluoride. The substrate is exposed to the second plasma to deposit material on the sidewalls. Paragraphs [0067-0070] the gas supplied may or may not contain other components besides tungsten hexafluoride), wherein each cycle of the plasma etching comprises the first etch step and the second step (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process. In an alternative interpretation, in the cyclic etching process taught, the first instance of step 430 could be considered the first instance of the claimed “first etch step” and the following instance of step 420 could be considered the first instance of the claimed “second etch step”).
Veber fails to teach that the second step is an etch step to remove a portion of the first passivation layer.
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]).
Han teaches methods of fabricating a semiconductor device that include etching a layer on a substrate (Paragraph [0004]). Han teaches that a method of etching that includes a first etch process that forms a layer on the sidewalls of a trench from ions from the plasma and by-products of the etching process (Paragraph [0043] first sidewall patterns are formed). Han teaches that the method of etching includes a second etch process that deforms the first layer formed on the sidewall and further deposits material on the sidewalls to form a second layer on the sidewalls (Paragraphs [0047-0048]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Veber by modifying the second step such that the second step included both etching the first passivation layer, as taught by Han, and forming a second passivation layer with the tungsten hexafluoride gas, as taught by Veber. This would be possible because as taught by Dole, the use of tungsten hexafluoride as a plasma process gas can allow for a process that both etches and deposits material.
One of ordinary skill in the art would have been motivated to make this modification because by modifying the shape of the sidewall passivation as taught by Han, the etch target layer could be more effectively etched (Han Paragraph [0058]). This modification would have been obvious as it can be considered the application of a known technique to a known method to yield predictable results. The method of Veber can be considered a base method and the teachings of Han, regarding the second process step, would be applicable to this base method (because, as taught by Dole, tungsten hexafluoride is a process gas known to be suitable for such a process step) and would have had the predictable result of a second step that would both etch a first passivation layer and deposit a second passivation layer. See MPEP 2143(I)(D).
Regarding Claim 2, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the second plasma is further generated from a precursor gas mixture comprising nitrogen (N2) and hydrogen (H2), and wherein the tungsten containing precursor gas comprises tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6. Paragraph [0068] second plasma can include hydrogen (H2). Paragraph [0076] second plasma can include nitrogen (N2)).
Regarding Claim 3, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the tungsten containing precursor gas comprises tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6).
Veber fails to teach wherein the second plasma is further generated from a precursor gas mixture comprising oxygen (O2), and carbonyl sulfide (COS). However, Veber teaches that the second plasma can include an oxygen-containing reactant (Paragraph [0037]).
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]). Dole further teaches that the composition of the process gas can include oxidants, such as O2 and COS (Paragraph [0041]).
It would be obvious to one of ordinary skill in the art to include O2 and COS within the precursor gas, as the oxygen-containing reactants taught by Veber since, as taught by Dole, O2 and COS are known process gases and oxidants to include with tungsten hexafluoride and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Regarding Claim 4, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the tungsten containing precursor gas comprises tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6).
Veber fails to teach wherein the second plasma is further generated from a precursor gas mixture comprising oxygen (O2). However, Veber teaches that the second plasma can include an oxygen-containing reactant (Paragraph [0037]).
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]). Dole further teaches that the composition of the process gas can include oxidants, such as O2 (Paragraph [0041]).
It would be obvious to one of ordinary skill in the art to include O2 within the precursor gas, as the oxygen-containing reactants taught by Veber since, as taught by Dole, O2 are known process gases and oxidants to include with tungsten hexafluoride and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Regarding Claim 5, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the patterned mask comprises an amorphous carbon layer (ACL) (Paragraph [0049] the mask layer can contain amorphous carbon).
Regarding Claim 6, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the carbon containing precursor gas comprises a fluorocarbon (Paragraphs [0049-0052] the first etch generates a first plasma using an etch chemistry that includes fluorocarbons).
Regarding Claim 7, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the second etch step is performed after the first etch step without an intervening purge step (Paragraph [0049] Figure 4 no purge step is taught).
Regarding Claim 8, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches wherein the second etch step forms a second passivation layer comprising tungsten over the patterned mask (Paragraph [0073] the deposition of the protective film can occur on the mask layer).
Regarding Claim 9, modified Veber teaches all the limitations of claim 1 as outlined above.
Veber fails to explicitly teach wherein the first etch step is performed for a first duration and the second etch step is performed for a second duration, the second duration being shorter than the first duration.
However, Veber teaches that exposing the substrate to the second plasma can occur for between 0.5 and 1000 seconds and that the exposure time for the second plasma may be different than the exposure time for the first plasma (Paragraph [0074]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated an exposure time for the first plasma that was different than the exposure time for the second plasma such that second duration was shorter than the first duration as claimed. One of ordinary skill in the art practicing the method of modified Veber would have had to pick some duration for the exposure of the first plasma would have had a reasonable expectation of success is selection a suitable duration. This selection would have been obvious as Veber teaches that the exposure time for the two plasmas can be different and when they are different there are only two possible situations: either the first duration is shorter or the second duration is shorter. See MPEP 2143(I)(E).
Regarding Claim 10, Veber teaches a method of plasma etching a substrate, the method comprising cyclically (Paragraph [0002] teaches a method that includes plasma etching a substrate. Paragraph [0087] the process can be repeated cyclically):
etching a target material with a first plasma (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process), the substrate comprising a patterned mask disposed over the target material and having openings in the patterned mask (Paragraph [0046] Figure 3A substrate (element 300) includes a patterned mask layer (element 302) that includes openings and is over the substrate layer, which is etched), the etching of the target material comprising forming a first passivation layer comprising a polymer material over sidewalls of the openings while etching the target material (Paragraph [0051] The substrate is etched by exposure to the plasma. Paragraph [0055] the etch process forms a sidewall coating from polymeric material); and
with a second plasma that is free of fluorocarbons depositing a second passivation layer comprising tungsten (Paragraphs [0066-0067] a second plasma is formed, using a metal-containing gas that can be tungsten hexafluoride. The substrate is exposed to the second plasma to deposit material on the sidewalls. Paragraphs [0067-0070] the gas supplied may or may not contain other components besides tungsten hexafluoride, therefore the gas can be free of fluorocarbons), wherein each cycle of the plasma etching comprises etching with the first plasma and the second plasma (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process. In an alternative interpretation, in the cyclic etching process taught, the first instance of step 430 could be considered the first instance of the claimed “first etch step” and the following instance of step 420 could be considered the first instance of the claimed “second etch step”).
Veber fails to teach that the second step is an etch step that etches a part of the first passivation layer.
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]).
Han teaches methods of fabricating a semiconductor device that include etching a layer on a substrate (Paragraph [0004]). Han teaches that a method of etching that includes a first etch process that forms a layer on the sidewalls of a trench from ions from the plasma and by-products of the etching process (Paragraph [0043] first sidewall patterns are formed). Han teaches that the method of etching includes a second etch process that deforms the first layer formed on the sidewall and further deposits material on the sidewalls to form a second layer on the sidewalls (Paragraphs [0047-0048]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Veber by modifying the second step such that the second step included both etching the first passivation layer, as taught by Han, and forming a second passivation layer with the tungsten hexafluoride gas, as taught by Veber. This would be possible because as taught by Dole, the use of tungsten hexafluoride as a plasma process gas can allow for a process that both etches and deposits material.
One of ordinary skill in the art would have been motivated to make this modification because by modifying the shape of the sidewall passivation as taught by Han, the etch target layer could be more effectively etched (Han Paragraph [0058]). This modification would have been obvious as it can be considered the application of a known technique to a known method to yield predictable results. The method of Veber can be considered a base method and the teachings of Han, regarding the second process step, would be applicable to this base method (because, as taught by Dole, tungsten hexafluoride is a process gas known to be suitable for such a process step) and would have had the predictable result of a second step that would both etch a first passivation layer and deposit a second passivation layer. See MPEP 2143(I)(D).
Regarding Claim 11, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the second plasma is generated from a precursor gas mixture comprising nitrogen (N2), hydrogen (H2), and tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6. Paragraph [0068] second plasma can include hydrogen (H2). Paragraph [0076] second plasma can include nitrogen (N2)).
Regarding Claim 12, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the tungsten containing precursor gas comprises tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6).
Veber fails to teach wherein the second plasma is further generated from a precursor gas mixture comprising oxygen (O2), and carbonyl sulfide (COS). However, Veber teaches that the second plasma can include an oxygen-containing reactant (Paragraph [0037]).
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]). Dole further teaches that the composition of the process gas can include oxidants, such as O2 and COS (Paragraph [0041]).
It would be obvious to one of ordinary skill in the art to include O2 and COS within the precursor gas, as the oxygen-containing reactants taught by Veber since, as taught by Dole, O2 and COS are known process gases and oxidants to include with tungsten hexafluoride and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Regarding Claim 13, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the tungsten containing precursor gas comprises tungsten fluoride (WF6) (Paragraph [0067] second plasma includes a metal-containing gas that can be WF6).
Veber fails to teach wherein the second plasma is further generated from a precursor gas mixture comprising oxygen (O2). However, Veber teaches that the second plasma can include an oxygen-containing reactant (Paragraph [0037]).
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]). Dole further teaches that the composition of the process gas can include oxidants, such as O2 (Paragraph [0041]).
It would be obvious to one of ordinary skill in the art to include O2 within the precursor gas, as the oxygen-containing reactants taught by Veber since, as taught by Dole, O2 are known process gases and oxidants to include with tungsten hexafluoride and the selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See MPEP 2144.07.
Regarding Claim 14, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the patterned mask comprises an amorphous carbon layer (ACL) (Paragraph [0049] the mask layer can contain amorphous carbon).
Regarding Claim 15, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the first plasma is generated from a precursor gas mixture comprising a fluorocarbon (Paragraphs [0049-0052] the first etch generates a first plasma using an etch chemistry that includes fluorocarbons).
Regarding Claim 16, modified Veber teaches all the limitations of claim 10 as outlined above. Veber further teaches wherein the etching with the second plasma is performed after the etching with the first plasma without an intervening purge step (Paragraph [0049] Figure 4 no purge step is taught).
Regarding Claim 17, modified Veber teaches all the limitations of claim 10 as outlined above.
Veber fails to explicitly teach wherein the first etch step is performed for a first duration and the second etch step is performed for a second duration, the second duration being shorter than the first duration.
However, Veber teaches that exposing the substrate to the second plasma can occur for between 0.5 and 1000 seconds and that the exposure time for the second plasma may be different than the exposure time for the first plasma (Paragraph [0074]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated an exposure time for the first plasma that was different than the exposure time for the second plasma such that second duration was shorter than the first duration as claimed. One of ordinary skill in the art practicing the method of modified Veber would have had to pick some duration for the exposure of the first plasma would have had a reasonable expectation of success is selection a suitable duration. This selection would have been obvious as Veber teaches that the exposure time for the two plasmas can be different and when they are different there are only two possible situations: either the first duration is shorter or the second duration is shorter. See MPEP 2143(I)(E).
Regarding Claim 21, Veber teaches a method of plasma etching a substrate, the method comprising cyclically (Paragraph [0002] teaches a method that includes plasma etching a substrate. Paragraph [0087] the process can be repeated cyclically):
etching a target material with a first plasma (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process), the substrate comprising an amorphous carbon layer (ACL) over the target material and having openings in the ACL (Paragraph [0046] Figure 3A substrate (element 300) includes a patterned mask layer (element 302) that includes openings and is over the substrate layer, which is etched. Paragraph [0049] the mask layer can contain amorphous carbon), the etching of the target material comprising forming a first passivation layer comprising a polymer material over sidewalls of the openings while etching the target material (Paragraph [0051] The substrate is etched by exposure to the plasma. Paragraph [0055] the etch process forms a sidewall coating from polymeric material), the first plasma comprising a fluorocarbon (Paragraphs [0049-0052] the first etch generates a first plasma using an etch chemistry that includes fluorocarbons); and
with a second plasma depositing a second passivation layer comprising tungsten, the second plasma being generated from a precursor gas mixture comprising tungsten fluoride (WF6), the precursor gas mixture being free of fluorocarbons (Paragraphs [0066-0067] a second plasma is formed, using a metal-containing gas that can be tungsten hexafluoride. The substrate is exposed to the second plasma to deposit material on the sidewalls. Paragraphs [0067-0070] the gas supplied may or may not contain other components besides tungsten hexafluoride, therefore the gas can be free of fluorocarbons), wherein each cycle of the plasma etching comprises etching with the first plasma and the second plasma (Paragraph [0049] Figure 4 a first etch step (element 410) is conducted, utilizing a first plasma. Following the second step (element 420), another etch step (element 430) is conducted. Paragraph [0087] the process steps represented by 420 and 430 can be cyclically repeated. Paragraphs [0080-0085] the process conditions of the “second plasma” used in step 430 may be more aggressive or different than those used in step 410, which means that they could be the same or similar such that step 430 and step 410 could both be considered iterations of the claimed “first etch step” within the cyclic process. In an alternative interpretation, in the cyclic etching process taught, the first instance of step 430 could be considered the first instance of the claimed “first etch step” and the following instance of step 420 could be considered the first instance of the claimed “second etch step”).
Veber fails to teach that the second step is an etch step that etches a part of the first passivation layer.
Dole teaches methods of etching a semiconductor substrate (Paragraph [0004]). Dole teaches a method of etching that utilizes a plasma generated from a process gas that comprises tungsten hexafluoride (WF6) (Paragraph [0005]). Dole teaches that during etching, tungsten-containing fragments will deposit on sidewalls (Paragraph [0010]).
Han teaches methods of fabricating a semiconductor device that include etching a layer on a substrate (Paragraph [0004]). Han teaches that a method of etching that includes a first etch process that forms a layer on the sidewalls of a trench from ions from the plasma and by-products of the etching process (Paragraph [0043] first sidewall patterns are formed). Han teaches that the method of etching includes a second etch process that deforms the first layer formed on the sidewall and further deposits material on the sidewalls to form a second layer on the sidewalls (Paragraphs [0047-0048]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Veber by modifying the second step such that the second step included both etching the first passivation layer, as taught by Han, and forming a second passivation layer with the tungsten hexafluoride gas, as taught by Veber. This would be possible because as taught by Dole, the use of tungsten hexafluoride as a plasma process gas can allow for a process that both etches and deposits material.
One of ordinary skill in the art would have been motivated to make this modification because by modifying the shape of the sidewall passivation as taught by Han, the etch target layer could be more effectively etched (Han Paragraph [0058]). This modification would have been obvious as it can be considered the application of a known technique to a known method to yield predictable results. The method of Veber can be considered a base method and the teachings of Han, regarding the second process step, would be applicable to this base method (because, as taught by Dole, tungsten hexafluoride is a process gas known to be suitable for such a process step) and would have had the predictable result of a second step that would both etch a first passivation layer and deposit a second passivation layer. See MPEP 2143(I)(D).
Regarding Claim 22, modified Veber teaches all the limitations of claim 21 as outlined above. Veber further teaches wherein the precursor gas mixture further comprises nitrogen (N2), hydrogen (H2), oxygen (02), carbonyl sulfide (COS), or combinations thereof (Paragraph [0068] second plasma can include hydrogen (H2). Paragraph [0076] second plasma can include nitrogen (N2)).
Regarding Claim 23, modified Veber teaches all the limitations of claim 21 as outlined above. Veber further teaches wherein the etching with the first plasma is performed for a first duration and the etching with the second plasma is performed for a second duration, the second duration being different than the first duration (Paragraph [0074] exposing the substrate to the second plasma can occur for between 0.5 and 1000 seconds. The exposure time for the second plasma may be different than the exposure time for the first plasma).
Regarding Claim 25, modified Veber teaches all the limitations of claim 1 as outlined above.
Modified Veber as outlined above fails to teach wherein performing the first etch step comprises forming the first passivation layer with a primary facet and a secondary facet, and wherein performing the second etch step comprises removing secondary facet and depositing a second passivation layer comprising tungsten.
However, Han further teaches that in a process that comprises two process steps, where each step etches and deposits material on the sidewall of the feature being etched, the second step removes the pattern created by the first step by creating a new pattern (Paragraphs [0020] and [0051-0058] Figures 6 and 7 the first process step forms passivation layer that can be considered to comprise a first facet and a second facet, as shown in Figure 6. The second process step removes these facets and creates alternative facets, as shown in Figure 7. See reference images below).
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It would have been obvious to one of ordinary skill in the art to have modified the method of modified Veber such that during the second etch step, the second facet was removed and a different facet was formed with the formation of the second passivation layer. Examiner takes the position that this is equivalent to the limitation as claimed. Examiner notes that as seen in Figure 2 of the instant application, the removal of the second facet (labeled as element 23) does not comprise the full removal of the polymer material (element 22), but merely removes some of the polymer material such that a different shape of the polymer material is created, forming a different facet.
One of ordinary skill in the art would have been motivated to make this modification because by modifying the shape of the sidewall passivation as taught by Han, the etch target layer could be more effectively etched (Han Paragraph [0058]). Additionally, this modification could be considered the combination of prior art elements according to known methods to yield predictable results. This combination would have had the predictable result of modifying the shape of the passivation layer on the sidewalls during the second etching step. See MPEP 2143(I)(A).
Claim 24 are rejected under 35 U.S.C. 103 as being unpatentable over in view of Dole and Han, as applied to claim 1 above, and further in view of Demmin et al. (US-6635185-B2).
Regarding Claim 24, modified Veber teaches all the limitations of claim 1 as outlined above. Veber further teaches that the first etch step can be biased (Paragraph [0084] second plasma may be biased, where as outlined in the rejection of claim 1, the step that uses the second plasma can be considered to be equivalent to the first etch step). Dole further teaches that the second etch step can be biased (Paragraph [0005] the process utilizing tungsten hexafluoride can be biased).
Modified Veber as outlined above fails to teach wherein performing the first etch step comprises applying a first bias power at a first etch bias power level and wherein performing the second etch step comprises applying a second bias power at a second etch bias power level lower than the first etch bias power level.
Demmin teaches methods related to plasma etching (Column 1 lines 5-12). Demmin teaches that changing the bias used during plasma etching affects the results obtained by the etching process (Column 7 lines 15-25).
It would have been obvious to one of ordinary skill in the art to have modified the method of modified Veber such that the bias power applied during the second etch step was lower than the bias power applied during the first etch step, because Demmin teaches that changing the process parameters of a plasma etching process, such as the bias, is a result-effective variable which can be optimized and through the optimization of the bias powers applied during the two etching steps the claimed limitation could be achieved. See MPEP 2144.05 IIB.
Response to Arguments
The objections to the drawings have been withdrawn due to proper amendments remedying the issue moot.
Applicant’s arguments, see Remarks Pg. 1-2, filed 05/18/2026, with respect to the 35 U.S.C. § 103 rejection have been fully considered and are not persuasive.
Applicant argues that Veber fails to teach a cyclic process that can be considered the comprise a first etch step as claimed.
Examiner respectfully disagrees. Examiner has further clarified their position regarding the teachings of Veber in the rejections above. Although Veber does not teach the step represented by block 410 as part of the cyclic process, Examiner takes the position that the limitations regarding the claimed first etch step can be met steps taught by Veber represented by block 410 and 430 together, or in an alternative interpretation, by block 430 alone within the cyclic process taught by Veber.
Applicant argues that there is no motivation to combine the teachings of Veber, Han, and Dole as outlined in the rejections of the previous office action, in particular noting that Han teaches a process that involves different chemistry than Veber.
Examiner respectfully disagrees. First, examiner has presented an alternative rejection within this office action that relies on an interpretation that the etching of the second step is an inherent feature of the process taught by Veber. Second, relating to specific rejections argued against by applicant, as further clarified in the rejections above, Dole does provide a direct motivation to combine prior art. Third, examiner takes the position that even without this direct teaching by Dole there exists motivation to combine the prior art to meet the claimed limitations. Applicant highlighted the use of fluorine-containing gases taught by Veber; however this is only one process condition taught by Veber that can be used to control the conformality of the deposition of the protective layer (Veber Paragraphs [0077-0078]). Veber teaches that the goal of this control over the conformality of the deposition is to create a protective layer that would prevent undesired lateral etching and enable desired vertical etching (Veber Paragraph [0079]). This is substantially similar to the stated goals taught by Han, where controlling the conformality (specially the angles created by non-conformal deposition and etching on the sidewalls) is used to create a vertical sidewall (which would require vertical etching without undesired lateral etching) (Han Paragraph [0061]). Examiner takes the position that although some of the specific chemistries involved in the methods taught by Han and Veber differ, one of ordinary skill in the art would understand the commonality between the two prior arts, namely control over the conformality of the sidewall deposition and shape of the sidewall to create the desired etched feature shape, and be able to apply the teachings of Han to the method of Veber.
Examiner would also like to clarify that the rejections are not proposing to replace the chemistry taught by Veber with the chemistry taught by Han.
Conclusion
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.
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/A.K.L./Examiner, Art Unit 1713 /DUY VU N DEO/Primary Examiner, Art Unit 1713
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