DETAILED ACTION
This is the Office action based on the 19051385 application filed February 12, 2025, and in response to applicant’s argument/remark filed on May 26, 2026. Claims 1-20 are currently pending and have been considered below.
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 .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103:
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 of this title, 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 1-8 and 10-20 rejected under 35 U.S.C. 103 as obvious over Blomberg et al. (U.S. PGPub. No. 20180182597), hereinafter “Blomberg”, in view of Chen et al. (U.S. PGPub. No. 20190122865), hereinafter “Chen”, and Brooks et al. (U.S. Pat. No. 5786276) hereinafter “Brooks”:--Claims 1, 2, 3, 4, 5, 6, 7, 12, 16, 18: Blomberg teaches a method of etching a substrate, comprisingi) providing a substrate comprising a metal, such as Hf or HfO2 ([0144]);ii) exposing the substrate to a first gas comprising a fluorinating gas, then removing excess first gas (Steps 500 and 510 in Fig. 5; [0022, 0083-0092]); iii) exposing the substrate to a second gas comprising a chlorinating gas, then removing excess second gas (Steps 520 and 530 in Fig. 5);iv) repeating steps i) and ii) a plurality of cycles ([0040, 0128]). Blomberg further teaches that the first gas may form reactant species on the substrate surface, the second gas may react with the reactant species to form volatile species comprising one or more atoms from the substrate surface, and the volatile species may be removed from the reaction chamber, such as by purging with an inert gas ([0006]). Blomberg further teaches that the fluorinating gas may be NF3 ([0072-0076, 0097]) and the chlorinating gas may be BCl3 ([0027-0031, 0097]), and that the etching process may be thermal etching or plasma etching ([0068, 0077]). Blomberg further teaches that the surface may be pre-treated with plasma ([0133]). Blomberg further teaches that one or more additional step of exposing the substrate to a reactant gas or a purge gas may be added before step ii) ([0085]), wherein the reactant may comprise oxygen, water or ozone and a halide, or an oxygen scavenger, such as CHyClx or CCl4 , or a ligand-exchanger, such as Hacac, TMA, Sn(acac)2, hexafluoro acetylacetonato (Hhfac), diacetyl, thd, M(thd)x, wherein M is metal, such as a transition metal or alkaline earth metal, and x can be greater than 1, or a metal and at least one ‘thd’ and/or at least one ‘acac’ group, or both, for example Mg(thd)(acac). ([0122-0125]). Therefore, it would have been obvious to one of ordinary skill in the art, in routine experimentations, to expose the substrate having the Hf or HfO2 to expose to a plasma comprising oxygen prior to step ii). This would inherently modify at least a portion of the metal oxide layer at the top surface to an amorphous metal oxide, as taught by Applicant ([0007], claim 6). Since the modified metal oxide is exposed to the plasma comprising the fluorinating gas, the contacting would inherently produce at least some hafnium oxy-fluoride, as taught by Applicant. Since the HfO2 substrate is exposed to the plasma comprising the fluorinating gas, the contacting would inherently produce at least some hafnium oxy-fluoride, as taught by Applicant. According to MPEP 2112 “[T]he discovery of a previously unappreciated property of a prior art composition, or of a scientific explanation for the prior art’s functioning, does not render the old composition patentably new to the discoverer.”, Atlas Powder Co. v. Ireco Inc., 190 F.3d 1342, 1347, 51 USPQ2d 1943, 1947 (Fed. Cir. 1999). Thus the claiming of a new use, new function or unknown property which is inherently present in the prior art does not necessarily make the claim patentable. In re Best, 562 F.2d 1252, 1254, 195 USPQ 430, 433 (CCPA 1977)”. Blomberg is silent about a method of forming the plasma.
Chen, also directed to a method of treating a substrate with an oxygen plasma ([0049]), teaches that the oxygen plasma may be formed in a remote plasma system by a power about 100-20KW ([0054]), then is directed to the substrate (Fig. 2A, [0044]). Brooks, also directed to a method of fluorine-based plasma etching while using PID temperature control and remote plasma, teaches that remote formation of the plasma advantageously prevent ions from the plasma damaging the wafer or causing unwanted heating of the wafer (Col. 4, Line 57 through Col. 5, Line 5).
Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to form the plasma in a remote plasma system then direct the plasma to the substrate because Blomberg teaches that the etchant may be a plasma of oxygen but is silent about the details of forming the plasma, and Chen teaches that such method would be effective, and Brooks teaches that such method would advantageously prevent ions from the plasma damaging the wafer or causing unwanted heating of the wafer. It is noted that the plasma power range taught by Chen overlaps the power range taught in the specification ([0051]) and would cause an amorphous region at the surface of the substrate, as taught by Applicant.--Claims 4, 8: For the same reason taught by Chen and Brooks, it would also have been obvious to one of ordinary skill in the art at the effective filing date of the invention to form the plasma in a remote plasma system then direct the plasma to the substrate for steps ii) and iii). Since only non-ionic species are supplied to the chamber, the chamber would be plasma-free. Alternately, since Blomberg further teaches that thermal ALE methods can be more desirable in some situations than plasma ALE methods because thermal ALE methods can be less damaging to the underlying substrate ([0068]); therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to use a low power plasma, such as 100W, in the invention of Blomberg since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. It is noted that this is within the range 100-20KW taught by Chen.--Claims 10, 11: Blomberg further teaches that etching is performed at 0.001-100 torr. Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to perform step ii) at a pressure lower than 5 Torr and step iii) at above 20 Torr. --Claim 13: It is noted that water contains hydrogen.--Claim 14: Since Chen teaches that the oxygen plasma may be formed in a remote plasma system by a power about 100-20KW in a remote region and only non-ionic species are allowed to flow to the process chamber, and Blomberg teaches that plasma may cause damage to the substrate, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to use a low power plasma, such as 100W, in the invention of Blomberg to modify a thickness less than about 20 nm of the metal oxide since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233.--Claim 15: Chen teaches that the pressure of the chamber may be less than about 1 Torr ([0059-0060]).--Claims 17, 19: Blomberg further teaches that the etching may be performed at about 75°C to 600°C ([0141]). This overlaps the temperature range recited in claim 17 and 19.--Claim 20: Since Blomberg further teaches that the first gas may form reactant species on the substrate surface, the second gas may react with the reactant species to form volatile species comprising one or more atoms from the substrate surface, and the volatile species may be removed from the reaction chamber, such as by purging with an inert gas ([0006]), it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to cause an increase in the chamber pressure when flowing the purge gas into the chamber to remove the volatile species.
Claim 9 rejected under U.S.C. 103 as being obvious over Blomberg in view of Chen and Brooks as applied to claim 1 above, and further in view of Minkovich et al. (U.S. PGPub. No. 20070251939) hereinafter “Minkovich”: --Claim 9: Blomberg teaches the invention as above. Blomberg further teaches that the etching may be performed at about 75°C to 600°C ([0141]). In an experiment Blomberg further teaches that etching is performed at 458°C (Table 1). Blomberg is silent about a method of controlling the temperature at such temperature. Minkovich, also directed to controlling temperature of a wafer, teaches that the temperature may be controlled by using a PID controller, wherein temperature routinely fluctuates around a setpoint, and that when the temperature drops below the setpoint the PID controller provides heating to increase the temperature back to the setpoint (abstract, [0021]). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, during routine processing, to provide heating to the substrate to increase the temperature to 350°C in the invention of Blomberg because Blomberg teaches to control the temperature to 458°C but is silent about the details, and Minkovich teaches that temperature routinely drops below the setpoint during processing, and to provide heating to the substrate to increase the temperature back to the setpoint during PID temperature control. Since controlling the process temperature would cause the chamber temperature would fluctuate around a setpoint during the etching process, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, that the temperature in step iii) to be higher than in step ii). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to increase the temperature of the chamber prior to step iii), such as during adjusting the temperature to maintain such temperature.
Response to Arguments
Applicant's arguments filed May 26, 2026 have been fully considered as follows:--Regarding Applicant’s argument that one skilled in the art would have no motivation to combine Blomberg with Chen to introduce plasma effluents because introducing plasma effluents in Blomberg would frustrate the intended purpose of Blomberg, this argument is not persuasive. Blomberg clearly teaches that the substrate may be pre-treated by using a plasma, which may comprise oxygen ([0133, 0122-0125]). However, Blomberg is silent about a method of forming the plasma.
Chen, also directed to a method of treating a substrate with an oxygen plasma ([0049]), teaches that the oxygen plasma may be formed in a remote plasma system by a power about 100-20KW ([0054]), then is directed to the substrate (Fig. 2A, [0044]). Brooks, also directed to a method of fluorine-based plasma etching while using PID temperature control and remote plasma, teaches that remote formation of the plasma advantageously prevent ions from the plasma damaging the wafer or causing unwanted heating of the wafer (Col. 4, Line 57 through Col. 5, Line 5).
Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to form the plasma in a remote plasma system then direct the plasma to the substrate because Blomberg teaches that the etchant may be a plasma of oxygen but is silent about the details of forming the plasma, and Chen teaches that such method would be effective, and Brooks teaches that such method would advantageously prevent ions from the plasma damaging the wafer or causing unwanted heating of the wafer. It is noted that the plasma power range taught by Chen overlaps the power range taught in the specification ([0051]) and would cause an amorphous region at the surface of the substrate, as taught by Applicant.--Regarding Applicant’s argument that one of skill in the art would not combine Blomberg with Chen because Blomberg is directed to etching a metal oxide and Chen is directed to etching silicon nitride, this argument is not persuasive. One of skill in the art would be motivated to combine Blomberg with Chen because Blomberg teaches that the substrate may be pre-treated by using a plasma, which may comprise oxygen ([0133, 0122-0125]). However, Blomberg is silent about a method of forming the plasma, while Chen teaches a method of treating a substrate with an oxygen plasma ([0049]), --Regarding Applicant’s argument that Blomberg desires only a thermal ALE and purposefully avoids plasma, this argument is not persuasive. Blomberg clearly teaches that the substrate may be pre-treated by using a plasma, prior to performing the etching. Furthermore, Blomberg teaches that the etching process itself may be thermal etching or plasma etching, although a thermal etching is preferable ([0068, 0077]).
Conclusion
THIS ACTION IS MADE FINAL. See MPEP §706.07(a). 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 extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to THOMAS PHAM whose telephone number is (571) 270-7670 and fax number is (571) 270-8670. The examiner can normally be reached on MTWThF9to6 PST.
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/THOMAS T PHAM/Primary Examiner, Art Unit 1713
