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 .
Response to Amendment
Claims 1-12 are pending in the Preliminary Amendment filed 08/16/2024.
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 1-7 and 10-12 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu et al. (US 20190206696 A1).
As to claim 1, discloses an etching method comprising:
an etching step [claim 1] of setting a temperature of a member to be etched having an etching object containing silicon to 00C or less [claim 14], bringing an etching gas containing an etching compound into contact with the member to be etched, and etching the etching object [claim 1 and claim 14],
wherein the etching gas contains or does not contain high-boiling-point impurities, the high- boiling-point impurities being compounds having at least one type of atom among a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydrogen atom, and an oxygen atom in a molecule and having a boiling point of 20°C or more under a pressure of 101 kPa, and, when the etching gas contains the high-boiling-point impurities, a total concentration of all types of the contained high-boiling-point impurities is 500 ppm by volume or less [claim 1; para. 0123, “The disclosed fluorine containing etching gases are provided at greater than 95% by volume purity, preferably at greater than 99.99% by volume purity, and more preferably at greater than 99.999% by volume purity. The disclosed fluorine containing etching gases contain less than 5% by volume trace gas impurities, with less than 150 ppm by volume of impurity gases, such as N.sub.2 and/or H.sub.2O and/or CO.sub.2, contained in said trace gaseous impurities. For example, FNO has less than 0.1% by volume trace gas impurities that include F.sub.2, HF, and H.sub.2O. Preferably, the water content in the disclosed fluorine containing etching gases is less than 20 ppmw by weight.”].
Hsu at para. 0123, fails to explicitly disclose a specific example (i.e., “less than 0.1% by volume trace gas impurities that include F.sub.2, HF, and H.sub.2O.”, or less than 1000 ppm) that is within the claimed range (i.e., “a total concentration of all types of the contained high-boiling-point impurities is 500 ppm by volume or less”), but nonetheless discloses broad ranges that encompasses the claimed range, and therefore supports a prima facie case of obviousness over the claimed range. See MPEP 2144.05, I.
As to claim 2, modified Hsu discloses the etching method according to claim 1, wherein the total concentration of all types of the contained high-boiling-point impurities is 0.01 ppm by volume or more and 300 ppm by volume or less [para. 0123, “greater than 99.99% by volume purity”, which overlaps the claimed range and therefore supports a prima facie case of obviousness, see MPEP 2155.05, I].
As to claim 3, modified Hsu discloses the etching method according to claim 1, wherein the high- boiling-point impurity is at least one type among water [para. 0123], hydrogen fluoride [para. 0123], ethanol, isopropanol, chloroform, dichloromethane, cyclohexane, benzene, iodine molecules, and bromine molecules.
As to claim 4, modified Hsu discloses the etching method according to claim 1,wherein the etching compound is a compound having at least one type of atom among a fluorine atom [para. 0123, “FNO”, nitrosyl fluoride], a chlorine atom [para. 0136], a bromine atom [para. 0136], an iodine atom, and a hydrogen atom in a molecule and having a boiling point of 15°C or less under a pressure of 101 kPa [para. 0123].
As to claim 5, modified Hsu discloses the etching method according to claim 4, wherein the etching compound is the compound having a fluorine atom in the molecule [Fig. 6, para. 0136] and is at least one type among sulfur hexafluoride, nitrogen trifluoride, chlorine trifluoride, iodine heptafluoride, phosphorus trifluoride, silicon tetrafluoride, fluorine gas [Fig. 6, para. 0136], trifluoroiodomethane, carbonyl fluoride, trifluoromethyl hypofluoride, chain saturated perfluorocarbons having 1 or more and 3 or less carbon atoms, chain saturated hydrofluorocarbons having 1 or more and 3 or less carbon atoms, unsaturated perfluorocarbons having 2 or more and 5 or less carbon atoms, unsaturated hydrofluorocarbons having 2 or more and 4 or less carbon atoms, cyclic perfluorocarbons having 3 or more and 5 or less carbon atoms, and cyclic hydrofluorocarbons having 3 or more and 5 or less carbon atoms.
As to claim 6, modified Hsu discloses the etching method according to claim 4, wherein the etching compound is the compound having a chlorine atom in the molecule and is at least one type among boron trichloride, chlorine gas [para. 0136], hydrogen chloride, chlorine trifluoride, chain saturated chlorinated hydrocarbons having 1 or more and 3 or less carbon atoms, and unsaturated chlorinated hydrocarbons having 2 or 3 carbon atoms.
As to claim 7, modified Hsu discloses the etching method according to claim 4, wherein the etching compound is the compound having a bromine atom in the molecule and is at least one type among hydrogen bromide [para. 0136], chain saturated brominated hydrocarbons having 1 or more and 3 or less carbon atoms, and unsaturated brominated hydrocarbons having 2 carbon atoms.
As to claim 10, modified Hsu discloses the etching method according to claim 2, wherein the high-boiling-point impurity is at least one type among water [para. 0123], hydrogen fluoride [para. 0123], ethanol, isopropanol, chloroform, dichloromethane, cyclohexane, benzene, iodine molecules, and bromine molecules.
As to claim 11, modified Hsu discloses the etching method according to claim 2, wherein the etching compound is a compound having at least one type of atom among a fluorine atom [para. 0123], a chlorine atom [para. 0136], a bromine atom [para. 0136], an iodine atom, and a hydrogen atom [para. 0136] in a molecule and having a boiling point of 15°C or less under a pressure of 101 kPa.
As to claim 12, modified Hsu discloses the etching method according to claim 3, wherein the etching compound is a compound having at least one type of atom among a fluorine atom [para. 0123], a chlorine atom [para. 0136], a bromine atom [para. 0136], an iodine atom, and a hydrogen atom [para. 0136] in a molecule and having a boiling point of 15°C or less under a pressure of 101 kPa.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Hsu et al. (US 20190206696 A1), as applied to claims 1-7 and 10-12 above, and further in view of Tomura (US 20190074190 A1).
As to claim 8, Hsu discloses the etching method according to claim 4, but fails to explicitly disclose:
wherein the etching compound is the compound having an iodine atom in the molecule and is at least one type among iodine heptafluoride, hydrogen iodide, trifluoroiodomethane, and pentafluoroiodoethane.
However, Tomura (US 20190074190 A1) teaches a low temperature etching method [Abstract; para. 0053, “temperature of the workpiece W is set to a temperature of 0° C. or less”; claim 1] utilizing fluorine-containing etchant [para. 0050, “one or more of fluorocarbon gas such as CF.sub.4 gas, hydrofluorocarbon gas, SF.sub.6 gas, and NF.sub.3 gas”] and an iodine-containing etchant [para. 0050, “one or more gases selected from hydrogen iodide gas (HI gas), iodofluorocarbon gas (CF.sub.xI.sub.y gas or C.sub.zF.sub.xI.sub.y gas), IF.sub.5 gas, IF.sub.7 gas, and iodine gas (I.sub.2 gas).”] to etch a silicon nitride film [para. 0051-54, para. 0061].
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of etching a silicon nitride film, of Hsu, to include the etch chemistry for etching a silicon nitride film, of Tomura, in order to effectively etch a silicon nitride film, as taught by Tomura [Abstract; claim 1]
Claims 1-2, 4, 7, 9, and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Nakamura et al. (US 5316616 A).
As to claim 1, Nakamura discloses an etching method [Abstract; claim 1] comprising:
an etching step of setting a temperature of a member to be etched having an etching object containing silicon to 00C or less [claim 1], bringing an etching gas containing an etching compound into contact with the member to be etched, and etching the etching object [claim 1],
wherein the etching gas contains or does not contain high-boiling-point impurities, the high- boiling-point impurities being compounds having at least one type of atom among a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydrogen atom, and an oxygen atom in a molecule and having a boiling point of 20°C or more under a pressure of 101 kPa [Examples 29-31, CO2], and, when the etching gas contains the high-boiling-point impurities, a total concentration of all types of the contained high-boiling-point impurities is 500 ppm by volume or less [Example 31, “30 ppm (by volume CO2)”].
Example 31 of Nakamura utilizes a temperature of 50 to 150 degrees Celsius to achieve vertical etching [Table 6, Example 31], and therefore fails to anticipate claim 1.
However, Nakamura teaches that an etching temperature of 00C or less [claim 1; Fig. 5] may be optimized to achieve a desired inclination angle of the side wall of the etched feature [Abstract; claim 1].
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the etching parameters of Example 31, to include an etching temperature that is 00C or less, of Nakamura, in order to achieve a desired inclination angle of the side wall of the etched feature, as taught by Nakamura [Abstract; claim 1].
As to claim 2, modified Nakamura discloses the etching method according to claim 1, wherein the total concentration of all types of the contained high-boiling-point impurities is 0.01 ppm by volume or more and 300 ppm by volume or less [Example 31, “30 ppm (by volume CO2)”].
As to claim 4, modified Nakamura discloses the etching method according to claim 1,wherein the etching compound is a compound having at least one type of atom among a fluorine atom, a chlorine atom, a bromine atom [Example 31], an iodine atom, and a hydrogen atom [Example 31] in a molecule and having a boiling point of 15°C or less under a pressure of 101 kPa.
As to claim 7, modified Nakamura discloses the etching method according to claim 4, wherein the etching compound is the compound having a bromine atom in the molecule and is at least one type among hydrogen bromide [Example 31], chain saturated brominated hydrocarbons having 1 or more and 3 or less carbon atoms, and unsaturated brominated hydrocarbons having 2 carbon atoms.
As to claim 9, modified Nakamura discloses the etching method according to claim 4, wherein the etching compound is the compound having a hydrogen atom in the molecule and is at least one type among chain saturated hydrocarbons having 1 or more and 4 or less carbon atoms [Example 31, “CH.sub.4”], unsaturated hydrocarbons having 2 or more and 4 or less carbon atoms, and cyclic hydrocarbons having 3 or 4 carbon atoms.
As to claim 11, discloses the etching method according to claim 2, wherein the etching compound is a compound having at least one type of atom among a fluorine atom, a chlorine atom, a bromine atom [Example 31], an iodine atom, and a hydrogen atom [Example 31] in a molecule and having a boiling point of 15°C or less under a pressure of 101 kPa.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: The additionally cited references are cited to show etching methods utilizing etching gases comprising a specified purity level and/or cryogenic etching chemistries [Abstracts].
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/CHRISTOPHER REMAVEGE/Examiner, Art Unit 1713
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