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 .
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description: Figure 1 contains the characters “MFC”. Examiner notes that the Specification refers to a “mass flow controller” in paragraphs [0036] and [0040], which “MFC” may be intended to reference but the abbreviation is never used within the Specification. Corrected drawing sheets in compliance with 37 CFR 1.121(d), or amendment to the specification to add the reference character(s) in the description in compliance with 37 CFR 1.121(b) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Objections
Claim 1 is objected to because of the following informalities: line 7 recites “and; and” Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-10 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 1 recites the limitation "discharging the discharge gas to generate plasma" as part of the third step in line 8. Previously, as part of the second step, the discharge gas was supplied to the plasma chamber. It is unclear exactly what is required by the limitation "discharging the discharge gas” and how it relates to requirement that this step generate plasma. This limitation could be interpreted as requiring a continuation of the “supplying of the discharge gas” required during the second step. Alternatively, this limitation could be interpreted as requiring exhausting the discharge gas out of the plasma chamber as part of the process. Alternatively, this limitation could be interpreted as requiring discharging the discharge gas into an alternative chamber or portion of the claimed plasma chamber, where the plasma etching process would then take place. In each of the potential interpretations outlined above, it is unclear how this step directly relates to the requirement that this method step “generate plasma” as in each case such a step would not generate plasma without significant additional process step also being conducted. Due to the lack of clarity regarding what exactly is being required by the limitation "discharging the discharge gas to generate plasma", Claim 1 is indefinite. Claims 2-10 are indefinite due to being dependent upon claim 1. For the purpose of compact prosecution any supplying or discharging of the discharge gas, to or from any chamber, before during or after the plasma etching step will be considered as meeting the limitation “discharging the discharge gas to generate plasma”.
Claim 6 recites “and a silicon oxide thin film or a silicon nitride thin film is formed thereon”. It is unclear what exactly “thereon” refers to as both “an amorphous carbon layer” and “a silicon substrate” are referenced in the section immediately prior. Therefore, this limitation could require that the silicon oxide thin film or silicon nitride thin film be formed on top of an amorphous carbon layer, or it could require that the silicon oxide thin film or silicon nitride thin film be formed on top of a silicon substrate. As it is unclear what structure is exactly required, claim 6 is indefinite. For the purpose of compact prosecution claim 6 will be examined such that a silicon oxide thin film or a silicon nitride thin film formed on either a silicon substrate or an amorphous carbon layer will be considered as meeting the instant limitation.
Claims 8 and 9 each require a range of “a ratio of an etch selectivity” of one material “with respect to an etch selectivity” of another single material. It is unclear what is required by these claims because etch selectivity is, by definition, a ratio between the etch rates of one material and a different material in one process. Therefore, this limitation is requiring a range of a ratio between the two ratios of two different etch selectivities. However, the limitation only provides information on one material that is to be considered for each of the claimed etch selectivities. For example, each claim recites “…an etch selectivity of the silicon oxide thin film or the silicon nitride thin film…”, providing no further information regarding this etch selectivity and therefore it is unclear how this etch selectivity is supposed to be calculated (the etch rate of “the silicon oxide thin film or the silicon nitride thin film” will need to be compared to the etch rate of another, unspecified material, to calculate this etch selectivity). There is an alternative interpretation that the “ratio” recited refers back to the “etch selectivity” and therefore the claims are requiring a particular range of etch selectivity for the two materials mentioned within the claims. Further, claims 8 and 9 require that this “ratio of an etch selectivity” be exist “after the third step”, however there is nothing claimed within the method that occurs after the third step. Therefore, it is unclear even what process is occurring where the required “ratio of an etch selectivity” exists. There is an alternative interpretation of this limitation that the “ratio of an etch selectivity” should be determined based on the total etching completed during entirety of the third step. As it is unclear what exactly is required by claims 8 and 9, these claims are indefinite. Claim 10 is indefinite due to being dependent upon claim 8. For the purpose of compact prosecution, any teaching that meets limitations as interpreted in any of the above interpretations will be considered as meeting the claimed limitations.
Claim Interpretation
Claim 1 recites “a first step of vaporizing each of liquid heptafluoropropyl methyl ether (HFE-347mcc3) and liquid heptafluoroisopropyl methyl ether (HFE-347mmy)”. Examiner is interpreting the parenthetical terms “HFE-347mcc3” and “HFE-347mmy” as being merely alternative names for their respective preceding chemical compounds. As alternative names, these terms provide no additional structural limitations to the claims.
Claim Rejections - 35 USC § 103
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-3 and 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (KR-20220065365-A, machine translation) in view of Matsuura (US-20170243756-A1) and Kim et al. (US-20220246439-A1, hereafter Kim ’439).
Regarding Claim 1, Kim teaches a plasma etching method (Paragraph [0001] teaches a plasma etching method) comprising:
a first step of vaporizing liquid heptafluoropropyl methyl ether (HFE-347mcc3) (Paragraph [0008] a first step of vaporizing liquid heptafluoropropyl methyl ether);
a second step of supplying a discharge gas including a mixed gas and argon gas to a plasma chamber in which an etching target is received, wherein the mixed gas includes the vaporized heptafluoropropyl methyl ether (Paragraph [0008] second step of supplying discharge gas that includes argon and vaporized heptafluoropropyl methyl ether to a plasma chamber); and
a third step of discharging the discharge gas to generate plasma (Paragraph [0008] process includes supplying discharge gas that includes argon and vaporized heptafluoropropyl methyl ether to a plasma chamber), and plasma-etching the etching target using the generated plasma (Paragraph [0008] generating plasma of the discharge gas to etch a target).
Kim fails to teach that the first step includes vaporizing liquid heptafluoroisopropyl methyl ether (HFE-347mmy) and further includes supplying this vapor within the mixed gas. However, Kim does teach that another compound can be vaporized and included within the mixed gas (Paragraph [0008] pentafluoropropanol is vaporized and included in the mixed gas supplied to the plasma chamber).
Matsuura teaches methods of plasma etching silicon oxide (Paragraph [0001]). Matsuura teaches that the etching gas used can include multiple hydrofluoroether compounds, which can be heptafluoropropyl methyl ether and heptafluoroisopropyl methyl ether (Paragraphs [0015-0016]).
Kim ‘439 teaches methods of plasma etching (Paragraph [0001]). Kim ‘439 teaches the use of etchants that have low global warming potential and includes heptafluoroisopropyl methyl ether as one such etchant (Paragraphs [0006-0007]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Kim by either further including heptafluoroisopropyl methyl ether within the mixed gas, or alternatively replacing pentafluoropropanol with heptafluoroisopropyl methyl ether. With this modification, the heptafluoroisopropyl methyl ether would have been vaporized (as outlined by Kim with regards to both pentafluoropropanol and heptafluoropropyl methyl ether) such that it would be successfully supplied to the plasma chamber and utilized within the mixed in the generation of plasma.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. This modification would have the predictable result using of heptafluoroisopropyl methyl ether as an etchant with heptafluoropropyl methyl ether as is taught by Matsuura. See MPEP 2143(I)(A). Additionally, this modification would have been obvious as Kim teaches that pentafluoropropanol and heptafluoropropyl methyl ether are low global warming potential etchantants (Paragraph [0001]), while Kim ‘439 teaches that heptafluoroisopropyl methyl ether is a low global warming potential etchant (Paragraphs [0006-0007]). Therefore this modification could have been the simple substitution of one low global warming potential etchant for another. The simple substitution of one known element for another is likely to be obvious when predictable results are achieved. See MPEP §2143(B). Furthermore, 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 2, modified Kim teaches all the limitations of claim 1 as outlined above. Kim further teaches wherein in order to vaporize the liquid heptafluoropropyl methyl ether and provide the vaporized heptafluoropropyl methyl ether to the plasma chamber, a first container receiving therein the liquid heptafluoropropyl methyl ether is heated to a first temperature equal to or higher than a boiling point of the heptafluoropropyl methyl ether, and a connection pipe connecting the first container and the plasma chamber to each other is heated to a second temperature higher than the first temperature (Paragraph [0009] "a first container holding the liquid HFE-347mcc3 may be heated to a first temperature above the boiling point of the HFE-347mcc3, a first connecting pipe connecting the first container and the plasma chamber may be heated to a second temperature higher than the first temperature").
Regarding Claim 3, modified Kim teaches all the limitations of claim 1 as outlined above.
Kim does not explicitly teach that in order to vaporize the liquid heptafluoroisopropyl methyl ether and provide the vaporized heptafluoroisopropyl methyl ether to the plasma chamber, a second container receiving therein the liquid heptafluoroisopropyl methyl ether is heated to a third temperature equal to or higher than a boiling point of the heptafluoroisopropyl methyl ether, and a connection pipe connecting the second container and the plasma chamber to each other is heated to a fourth temperature higher than the third temperature.
However, Kim teaches that the same process as claimed for vaporizing a liquid etchant is suitable for pentafluoropropanol and heptafluoropropyl methyl ether (Paragraph [0009]). Kim ‘439 teaches that the claimed process can be used for the vaporization of heptafluoroisopropyl methyl ether in a similar plasma etching method (Paragraph [0040]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Kim by using the same vaporization methods taught within Kim for vaporizing heptafluoroisopropyl methyl ether, as Kim ‘439 teaches this method is suitable for heptafluoroisopropyl methyl ether.
This modification would have been obvious as it would have been the combination of prior art elements according to known methods to yield predictable results. This modification would have had the predictable result of proving a suitable means for supplying heptafluoroisopropyl methyl ether to the plasma chamber for the plasma etching process. See MPEP 2143(I)(A).
Regarding Claim 5, modified Kim teaches all the limitations of claim 1 as outlined above. Kim fails to explicitly teach wherein a bias voltage of -800 to -1200V is applied to a substrate supporting the etching target in the plasma chamber during the third step.
However, Kim further teaches that the bias voltage used can be between -1300V and -350V (Paragraph [0035]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a bias voltage at a level within the disclosed range of -1300V to -350V, including at amounts that overlap with the claimed range of -800V to -1200V. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Regarding Claim 6, modified Kim teaches all the limitations of claim 1 as outlined above. Kim further teaches wherein the etching target is a semiconductor substrate on which an amorphous carbon layer (ACL) is formed on a silicon substrate and a silicon oxide thin film or a silicon nitride thin film is formed thereon (Paragraph [0020] a substrate that can comprise a film of silicon oxide or silicon nitride can be the etching target, the substrate can further comprise any amorphous carbon layer).
Claims 4 and 7-10 are rejected under 35 U.S.C. 103 as being unpatentable over Kim in view of Matsuura and Kim ’439, as applied to claims 1 and 6 above, and further in view of Demmin et al. (US-6635185).
Regarding Claim 4, modified Kim teaches all the limitations of claim 1 as outlined above. Kim fails to explicitly teach that the mixed gas and the argon gas are supplied to the plasma chamber at a flow rate ratio of 1:2. However, Kim further teaches that the flow rate ratio of the etchant gases to the argon gas can be from 1:1 to 1:3 (Paragraph [0010]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a flow rate ratio for the mixed gas and argon gas at a level within the disclosed range of 1:1 to 1:3, including at amounts that overlap with the claimed value of 1:2. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Kim fails to teach wherein the vaporized heptafluoropropyl methyl ether and the vaporized heptafluoroisopropyl methyl ether in the mixed gas are supplied to the plasma chamber at a flow rate ratio of 1:3 to 3:1. However, Kim teaches that heptafluoropropyl methyl ether comprises 37.5-75% of fluorocarbon gas supplied (Paragraph [0010]).
Demmin teaches methods of plasma etching (Column 1, line 6-12). Demmin teaches that the etching composition flow rates are a result effective variable that affect 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 Kim by selecting a flow rate ratio for the vaporized heptafluoropropyl methyl ether and the vaporized heptafluoroisopropyl methyl ether in the mixed gas within the claimed range. This modification would have been obvious because Kim provides some guidance how much heptafluoropropyl methyl ether to include within a mixed gas of similar components, and Demmin teaches that the flow rates of different components within an etching composition for a plasma etching process are a result effective variable that affect the results achieved by the etching. See MPEP 2144.05 IIB.
Regarding Claim 7, modified Kim teaches all the limitations of claim 1 as outlined above. Kim fails to explicitly teach that the mixed gas and the argon gas are supplied to the plasma chamber at a flow rate ratio of 1:2. However, Kim further teaches that the flow rate ratio of the etchant gases to the argon gas can be from 1:1 to 1:3 (Paragraph [0010]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a flow rate ratio for the mixed gas and argon gas at a level within the disclosed range of 1:1 to 1:3, including at amounts that overlap with the claimed value of 1:2. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Kim fails to teach wherein the vaporized heptafluoropropyl methyl ether and the vaporized heptafluoroisopropyl methyl ether in the mixed gas are supplied to the plasma chamber at a flow rate ratio of 1:2.3 to 2.3:1. However, Kim teaches that heptafluoropropyl methyl ether comprises 37.5-75% of fluorocarbon gas supplied (Paragraph [0010]).
Demmin teaches methods of plasma etching (Column 1, line 6-12). Demmin teaches that the etching composition flow rates are a result effective variable that affect 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 Kim by selecting a flow rate ratio for the vaporized heptafluoropropyl methyl ether and the vaporized heptafluoroisopropyl methyl ether in the mixed gas within the claimed range. This modification would have been obvious because Kim provides some guidance how much heptafluoropropyl methyl ether to include within a mixed gas of similar components, and Demmin teaches that the flow rates of different components within an etching composition for a plasma etching process are a result effective variable that affect the results achieved by the etching. See MPEP 2144.05 IIB.
Regarding Claim 8, modified Kim teaches all the limitations of claims 1, 6, and 7 as outlined above. Modified Kim fails to explicitly teach wherein after the third step, a ratio of an etch selectivity of the silicon oxide thin film or the silicon nitride thin film with respect to an etch selectivity of the silicon substrate is 7.5 or greater.
However, Kim teaches that the etch selectivity of Si3N4 to poly-Si can range from about 2.5 to about 30 (Figure 3B shows that the etch selectivity of Si3N4 to poly-Si can range from about 2.5 to about 30 depending on the processing conditions).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated an etch selectivity of the silicon oxide thin film or the silicon nitride thin film with respect to the silicon substrate at a level within the disclosed range of about 2.5 to about 30, including at amounts that overlap with the claimed range of 7.5 or greater. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Regarding Claim 9, modified Kim teaches all the limitations of claims 1, 6, and 7 as outlined above. Modified Kim fails to explicitly teach wherein after the third step, a ratio of an etch selectivity of the silicon oxide thin film or the silicon nitride thin film with respect to an etch selectivity of the amorphous carbon layer (ACL) is 10 or greater.
However, Kim further teaches that the etch selectivity of SiO2 to ACL can range from about 5 to infinity based (Figure 3C shows that the etch selectivity of SiO2 to ACL can range from about 5 to infinity based on the processing conditions)
It would have been obvious to one of ordinary skill in the art to have selected and incorporated an etch selectivity of the silicon oxide thin film or the silicon nitride thin film with respect to the amorphous carbon layer at a level within the disclosed range of about 5 to infinity, including at amounts that overlap with the claimed range of 10 or greater. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Regarding Claim 10, modified Kim teaches all the limitations of claims 1, 6, 7, and 8 as outlined above. Kim fails to explicitly teach wherein a bias voltage of -800 to -1200V is applied to a substrate supporting the etching target in the plasma chamber during the third step.
However, Kim further teaches that the bias voltage used can be between -1300V and -350V (Paragraph [0035]).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a bias voltage at a level within the disclosed range of -1300V to -350V, including at amounts that overlap with the claimed range of -800V to -1200V. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Examiner takes the position that the limitation “wherein as a magnitude of the applied bias voltage increases, the ratio of the etch selectivity of the silicon oxide thin film or the silicon nitride thin film with respect to the etch selectivity of each of the silicon substrate and the amorphous carbon layer (ACL) decreases” is an intrinsic result of the process taught by the prior art. This limitation does not include an active method step but instead is describing a relationship that intrinsically exists between bias voltage and etch selectivity. Examiner further notes that this relationship, as claimed, is taught in Figure 3C of Kim.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDREW KEELAN LAOBAK whose telephone number is (703)756-5447. The examiner can normally be reached Monday - Friday 8:00am - 5:30pm.
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/A.K.L./ Examiner, Art Unit 1713 /DUY VU N DEO/Primary Examiner, Art Unit 1713
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