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 .
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on April 17, 2026 has been entered.
Claims 1, 4-6, and 8-20 are pending as amended on April 17, 2026. Support for amended claim 1 is found in [0101] of the instant specification and original claim 2. Claims 11-20 stand withdrawn from consideration.
Any objections and/or rejections made in the previous Office action and not repeated below are hereby withdrawn. The text of those sections of Title 35, U.S. Code not included in the action can be found in a prior Office action.
Response to Arguments
Applicant’s arguments, see page 8, filed April 17, 2026, with respect to the rejections of claims 1 and 6-9 under 35 U.S.C. 103 have been fully considered and are persuasive. Ogura (CN 109679343 A) does not suggest a diamine residue comprising TFMB residue, as required in amended claim 1. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Auman (US 2020/0140615 A1) in view of Kaneshiro (JP-2004292700-A) and Yun (US 2021/0198426 A1).
Applicant argues (page 8-9) that Ogura does not discuss residual stress in relation to Tg and CTE and therefore fails to provide a motivation to achieve the claimed HS stability balance. The new grounds of rejection similarly modifies the primary reference (Auman) with the residual stress taught by Yun, resulting in a range of HS index values that overlaps with the claimed range. The MPEP section 2144, subsection IV states, “The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant. See, e.g., In re Kahn, 441 F.3d 977, 987, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006).” In this case, one would have been motivated to modify the film of Auman to have the residual stress of Yun in order to utilize a suitable residual stress for avoiding defects. This modification leads to a range of HS stability values that overlaps with claimed range. Selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I.
Applicants may rebut a prima facie case of obviousness based on optimization of a variable disclosed in a range in the prior art by showing that the claimed variable was not recognized in the prior art to be a result-effective variable. E.I. Dupont de Nemours & Company v. Synvina C.V., 904 F.3d 996, 1008, 128 USPQ2d 1193, 1202 (Fed. Cir. 2018). See MPEP 2144.05 III. C. Applicant argues (page 9) that the HS index is critical. This argument is not persuasive because the obviousness rejections are based on overlapping HS index ranges, not optimized HS index ranges.
Applicant argues (page 9) that claim 1 is non-obvious because the specific monomeric combination required to achieve the interdependent HS Index and loop stiffness is neither taught nor suggested by the prior art. This argument is not persuasive because Auman teaches the claimed monomer combination.
Claim Rejections - 35 USC § 103
Claims 1, 4-6, and 8-10 are rejected under 35 U.S.C. 103 as being unpatentable over Auman (US 2020/0140615 A1) in view of Kaneshiro (JP-2004292700-A, English translation provided) and Yun (US 2021/0198426 A1, cited with 8/12/2025 Office action).
Regarding claims 1, 4, 6, and 8-9, Auman teaches a film comprising a polyimide layer comprising an aromatic diamine compound residue and an aromatic compound residue, wherein the aromatic dianhydride compound residue comprises PMDA residue, BPDA residue, and 6FDA residue and the aromatic diamine compound residue comprises TFMB residue (Auman, [0290] and Table 2). Auman’s dianhydride component consists of 50 mol% PMDA residue, 25 mol% BPDA residue, and 25 mol% 6FDA residue (Auman, PF-1 in Table 2). This reads on the three kinds of aromatic dianhydride compound residues comprise BPDA residue in an amount of 25 mol (claim 6) and PMDA in an amount of 50 mol% (claim 9) when the total amount of the aromatic dianhydride compound residue is 100 mol. The BPDA residue is about 33 mol% based on a sum of the number of moles of BPDA and PMDA (25/(25+50)=0.33) (claim 8).
The polyimide film has a yellowness index of 5 or less (Auman, [0266]), reading on claim 4. The coefficient of thermal expansion (H) is 5-30 ppm/°C (Auman, [0243]) and the glass transition temperature (Tg) is 350-450 °C (Auman, [0249]).
Auman does not teach the claimed loop stiffness value.
However, prior to the effective filing date of the claimed invention, loop stiffness was known to be a result effective variable for balancing warpage and heat resistance, as taught by Kaneshiro. Kaneshiro teaches polyimide substrates (Kaneshiro, [0001]) with a loop stiffness range of 3-50 g/cm (Kaneshiro, [0038]). This range converts to about 3-50 N/m (e.g. 3 g * 1kg/1000 g * 9.8 m/s^2 = 0.0294 N and 0.0294 N/cm * 100 cm/m = 2.94 N/m). Below this range, the warpage characteristics decrease and above this range the solder heat resistance deteriorates (Kaneshiro, [0038]).
Because Kaneshiro exemplifies a polyimide film thickness of 50 µm (Kaneshiro, [0054]), one of ordinary skill would have understood that a loop stiffness of 3-50 N/m based on a thickness of 50 µm is an appropriate loop stiffness. In addition, one would have understood that decreasing the loop stiffness leads to warpage and increasing the loop stiffness leads to decreased solder heat resistance. Therefore, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to have optimized the loop stiffness of Auman to any stiffness within the range of 3-50 N/m taught by Kaneshiro, including a loop stiffness that falls within the claimed range of 3-4.5 N/m based on a thickness of 50 µm. One would have been motivated to optimize the loop stiffness in order to balance warpage with heat resistance. The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980) (see MPEP § 2144.05, II.).
Auman does not teach the residual stress value (RS) needed to calculate the claimed HS index.
However, Yun teaches polyimide films used as flexible substrates (Yun,[0002]). Yun teaches a residual stress after curing the film on an inorganic substrate of 10 to 25 MPa (Yun, [0089]) and further teaches that when residual stress increases, bending of the substrate may occur, resulting in defects (Yun, [0071]). Given the disclosure Yun, one of ordinary skill would have recognized that a residual stress in the range of 10 to 25 MPa is desirable for polyimide films used in flexible substrates. Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to form a film according to Auman having a residual stress in the range of 10 to 25 MPa, as Yun demonstrates this range as being suitable for avoiding defects in similar films. This represents the use of a suitable range of residual stress in a similar flexible substrate application. "The combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results." KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 416-21 (2007). See MPEP 2141.
The range of heat resistance stability index (HS index) values are calculated using the formula
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. The low end of the HS index range taught by modified Auman is therefore about 4.7 °C2/ppm-MPa ((350 °C * 10)/(30 ppm/° C * 25 MPa) = 4.66 °C2/ppm-MPa). The high end of the HS index range taught by modified Auman is 90 °C2/ppm-MPa ((450 °C * 10)/(5 ppm/° C * 10 MPa) = 90 °C2/ppm-MPa). It would have been obvious to one of ordinary skill in the art to have selected any combination of Tg, H, and RS taught by modified Auman resulting in any HS index in the range of 4.7-90 °C2/ppm-MPa. A HS index range of 4.7-90 °C2/ppm-MPa overlaps with the claimed range of 5 to 15 °C2/ppm-MPa. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have selected the overlapping portion of the ranges disclosed by the reference because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I.
Regarding claim 5, modified Auman teaches the polyimide layer of claim 1 where the Tg is 350-450 °C, the yellowness index (YI) is 5 or less, and H is 5-30 ppm/°C. Auman further teaches a thickness of 5-25 µm (Auman, [0282]). It would have been obvious to one of ordinary skill in the art prior to the effective filing date to have selected a polyimide film with a YI of 5 or less when measured for any thickness taught by Auman, including a thickness of 10 µm.
The claimed T Index is calculated using the formula
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. The lower end of the T Index range taught by modified Auman is therefore 2.3 °C2/ppm ((350 °C)/(30 ppm/° C * 5) = 2.3). The upper end of the T Index range taught by modified Auman is 90 °C2/ppm ((450 °C)/(5 ppm/° C * 1) = 90). A range of 2.3-90 °C2/ppm falls within the claimed range of 2 °C2/ppm or more.
Regarding claim 10, modified Auman teaches the polyimide layer of claim 1. Auman further teaches an electronic device with a substrate, an anode layer, a cathode layer, and a photoactive layer (Auman, [0668]), reading on a multilayer electronic device. The polyimide film is the substrate layer (Auman, [0668], [0677], and [0101]). The photoactive layer reads on a radiant functional layer.
Conclusion
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/AUDRA J DESTEFANO/Examiner, Art Unit 1766
/RANDY P GULAKOWSKI/Supervisory Patent Examiner, Art Unit 1766
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