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 .
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 are rejected under 35 U.S.C. 103 as being unpatentable over Shah et al. (“Shah” US 2022/0199429), Osenbach et al. (“Osenbach” US 2022/0216127), Rawlings et al. (“Rawlings” US 2019/0393118), and Huang et al. (“Huang” US 2022/0399245).
Regarding claim 1, Shah discloses a method of manufacturing a semiconductor device (Figures 2B, 4), comprising:
adhering a first Thermal Interface Material (TIM) (202) over a first portion of a first package (chips 102/204, here the first portion is considered as the perimeter of the upper surfaces of the chips 102/104);
dispensing a second TIM (110) over a second portion of the first package (102/204, here the second portion is considered the inner region of the chips’ upper surfaces);
initiating an initial cross-linking of the first TIM (202) by curing the first TIM (202) after the dispensing the second TIM (110, see Figure 4 which shows the TIMs, “stiffening adhesive” 202 and TIM 110, being places on the chip prior to curing the “stiffening adhesive” TIM 202, see step 408, thus the TIM 202 undergoes an initial cross-linking due to the curing step, see also para. [0032]); and
attaching a heat sink (lid 106) to the first TIM (202, see Figure 2B, para. [0033]).
Shah does not disclose that the first TIM is formed from a phase-change material.
Osenbach discloses, however, a “containment ring” (102a) analogous to the claimed first TIM that is formed from a phase-change material (see para. [0080]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Osenbach into the teachings of Shah to include a phase-change material for the first TIM for the purpose of utilizing a material with higher strength (see Osenbach, para. [0080]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
Shah and Osenbach do not disclose that the second TIM is formed from a liquid metal.
Rawlings discloses, however, a second TIM (109) formed from a liquid metal (109, para. [0016]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Rawlings into the teachings of Shah and Osenbach to include that the second TIM is formed from a liquid metal for the purpose of increasing compliance to warping (para. [0013]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
Shah, Osenbach, and Rawlings do not teach that the first TIM has a first height, and wherein after dispensing the second TIM has a second height larger than the first height.
Huang teaches a first TIM (22) having a first height (see Figure 2B), and a second TIM (23) wherein after dispensing the second TIM (23) over a first portion of a first package (see Figure 2B, over the die 25), the second TIM has a second height larger than the first height (see height differences of the first TIM 22 and second TIM 23 after dispensing the second TIM 23, the second TIM 23 on the die has a greater height than that of the first TIM 22).
It would have been obvious to a person having ordinary skill in the art to incorporate the teachings of Huang into the teachings of Shah, Osenbach, and Rawlings to include the claimed height differences of the thermal interface materials. The combination would yield a predictable result to a person having ordinary skill in the art, where one must dispense enough of the second TIM to cover the larger, inner portion of the package relative to the smaller amount of the first TIM to cover the outer ring perimeter of the package, thus after dispensing, the predictable result would be a larger height of the second TIM than the height of the first TIM. See KSR International Co. v. Teleflex Inc., 82 USPQ2d 1385 (2007). Additionally, one of ordinary skill in the art before the effective filing date of the claimed invention would have recognized TIM coverage area to be a result effective variable affecting the height of the TIM after dispensing the TIM on the area it is to cover. Thus, it would have been obvious to modify the device of Shah, Osenbach, and Rawlings to have the relative thicknesses of the TIMs as claimed in order to adequately provide coverage of the top of the die, providing optimal heat dissipation, and since optimum or workable ranges of such variables are discoverable through routine experimentation. See MPEP 2144.05 II.B and 2143.
Regarding claim 2, Shah discloses wherein the first TIM (202) covers an exterior area of the first package (102/204, see Figure 2B) and the second TIM (110) covers an interior area of the first package (102/204, see Figure 2B).
Regarding claim 3, Shah further discloses forming a first strip (strip of first TIM 202 on the right side of the left sided die 102) of the first TIM (202) that bisects the first package (102/204, the strip of the first TIM 202 on the right side of the left sided chip 102 essentially bisects the package 102/204 into two parts), wherein the second portion (inner regions of upper surfaces of the chips 102/205) further comprises a first isolated region (inner upper surface of the left sided die 102) and a second isolated region (inner upper surface of the right sided die 204, see Figure 2B).
Regarding claim 4, Shah discloses wherein the first TIM (202) covers a perimeter of a die (chip 102, see Figure 2B) in the first package (102/204) and the second TIM (110) covers a first isolated area (area on the top surface of die 204) outside the first TIM (202, a portion of the second TIM 110 is located outside the first TIM 202 that covers the die 102, since a portion of the second TIM 110 is also placed on the other die 204) and a second isolated area (area on the top surface of die 102) inside the first TIM (202, see the first TIM 202 on the die 102 within which a portion of the second TIM 110 is place, thus is also located in a second isolated area inside the first TIM 202 on die 102).
Regarding claim 5, Shah discloses wherein the attaching the heat sink (106) to the first TIM (202) spreads the liquid metal (incorporated into the second TIM 110 by Rawlings) across the second portion (inner region of the chips’ 102/204 upper surfaces) of the first package (102/204, para. [0029] discloses that the application of the lid 106 will cause a degree of spreading of the first TIM 202, thus it would be obvious to a person having ordinary skill in the art that the application of the lid, since the lid is placed after the placement of the second TIM 110, would also spread the second TIM across the upper surfaces of the package).
Regarding claim 6, The combination of Shah, Osenbach, and Rawlings further discloses cross-linking the first TIM (202) to form a cross-linked gel (Shah discloses curing the first TIM 202, the materials of the TIMs incorporated by Osenbach and Rawlings, thus resulting in a cross-linked gel material).
Shah does not explicitly disclose a cross-linked gel. However, the instant specification does not provide any mechanism by which the cross-linking is formed other than a curing process, which Shah discloses (see para. [0034]). Therefore, a person of ordinary skill in the art would expect that, as Shah provides the disclosed method and Rawlings and Osenbach provide the TIM materials (phase change material and liquid metal), the cross-linking of the first TIM (202) by curing, a cross-linked gel would also have formed.
Regarding claim 7, The combination of Shah, Osenbach, and Rawlings further discloses cross-linking the first TIM with the second TIM to form a cross-linked product at an interface between the first TIM and the second TIM.
Shah does not explicitly disclose a cross-linked interface. However, the instant specification does not provide any mechanism by which the cross-linked interface is formed other than a curing process, which Shah discloses (para. [0034]). Therefore, a person of ordinary skill in the art would expect that, as Shah provides the curing method and Rawlings and Osenbach provide the TIM materials, the cross-linking of the first TIM and second TIM would also have occurred.
Claims 21, 23-24, and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Shah et al. (“Shah” US 2022/0199429), Osenbach et al. (“Osenbach” US 2022/0216127), Rawlings et al. (“Rawlings” US 2019/0393118), and Chee et al. (“Chee” US 2022/0344297).
Regarding claim 21, Shah discloses a method of manufacturing a semiconductor device (Figures 2A, 4) comprising:
bonding a package component (chip 102) to a package substrate (104, see Figure 2A, para. [0022]);
dispensing a boundary layer (202) on a perimeter of a first top surface of the package component (102, see Figure 2A), wherein during the dispensing a material of the boundary layer (202) has a first amount of cross- linking (the material of the boundary layer itself 202 would have a certain amount of cross-linking in its pre-cured form);
dispensing a [material] (110) onto the package component (102) within the perimeter (see Figure 2A);
placing a heat sink (106) in contact with the boundary layer (202) and the [material] (110, see Figure 2A);
performing a clamping process, the clamping process comprising pressing the heat sink (106) towards the package substrate (104, since the process disclosed by Shah describes the heat sink 106 being applied to the package component and the boundary layer causes a degree of spreading of the boundary layer 202, see para. [0029], thus it is obvious to a person having ordinary skill in the art that the application of the lid comprises pressing the lid towards the package substrate); and
after the performing the clamping process (406, see Figure 4), curing the boundary layer (202, para. [0034]) to increase cross-linking in the material of the boundary layer (202) from the first amount (amount during dispensing of the boundary layer 202) to a second amount (an increased amount, since the boundary layer 202 is hardened during the curing process), wherein after the curing the boundary layer (202) is solidified (see para. [0034]).
Shah does not disclose that the boundary layer comprises a phase-change material.
Osenbach discloses, however, a “containment ring” (102a) analogous to the claimed boundary layer that comprises a phase-change material (see para. [0080]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Osenbach into the teachings of Shah to include a phase-change material for the boundary layer for the purpose of utilizing a material with higher strength (see Osenbach, para. [0080]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
Shah and Osenbach not disclose that the material dispensed onto the package component within the perimeter is a liquid metal.
Rawlings discloses, however, a thermal interface material (109), analogous to the “material” 110 of Shah above, formed from a liquid metal (109, para. [0016]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Rawlings into the teachings of Shah and Osenbach to include that the material 110 of Shah is formed from a liquid metal for the purpose of increasing compliance to warping (para. [0013]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
The combination of Shah, Osenbach, and Rawlings teaches the limitation “wherein during the curing the boundary layer and the liquid metal intermingle in a liquid state”. Osenbach teaches the PCM material for the boundary layer has a melting point between 30°C and 85°C (para. [0008]), and Rawlings teaches the liquid metal has a melting point below 30°C (para. [0037]). Curing temperatures are greater than softening/melting temperatures of the material (as evidenced by Chee, see para. [0051]) in order to initiate the cross-linking of the material, thus would be greater than at the most 85°C. Curing at these above-melting temperatures would result in the boundary layer and the thermal interface material being physically in contact with each other, each in a liquid state, thus would intermingle during curing in a liquid state.
Regarding claim 23, The combination of Shah, Osenbach, and Rawlings discloses wherein the performing the clamping process spreads the liquid metal (liquid metal incorporated by Osenbach into TIM 110 of Shah, para. [0029] discloses that the application of the lid 106, or the pressing process of clamping, will cause a degree of spreading of the boundary layer 202, thus it would be obvious to a person having ordinary skill in the art that the application of the lid, since the lid is placed after the placement of the material 110, would also spread the material 110 across the upper surfaces of the chip 102), the boundary layer (202) keeping the liquid metal (110, liquid metal material incorporated by Rawlings) within the perimeter (see para. [0032] and Figure 2A, the boundary layer 202 frames the material 110).
Regarding claim 24, The combination of Shah, Osenbach, and Rawlings discloses wherein after the clamping process (Figure 4, 406) the liquid metal (110, liquid metal material incorporated by Rawlings) has a second top surface that is planar with a bottom surface of the heat sink (106, finished product of Figure 2A after the clamping/pressing/application of the lid 106 shows the surfaces coplanar with each other).
Claims 22 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Shah, Osenbach, Rawlings, and Chee as applied to claim 21 above, and further in view of Honeywell (Honeywell Portfolio of Products, Brochure, August 2021).
Regarding claim 22, the combinations of teachings of Shah, Osenbach, Rawlings, and Chee do not disclose that the boundary layer has a glass- transition temperature between about 45 °C and about 60 °C.
Honeywell discloses a phase-change material, analogous to the boundary layer of the combination of teachings above, has a glass- transition temperature between about 45 °C and about 60 °C (page 7 discloses that the phase change temperature is 45°C).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Honeywell into the teachings of Shah, Osenbach, and Rawlings to include wherein the boundary layer has a glass- transition temperature between about 45 °C and about 60 °C to provide optimal surface wetting at manufacturing temperatures (Honeywell, page 7).
Claims 27-31 and 33 are rejected under 35 U.S.C. 103 as being unpatentable over Shah et al. (“Shah” US 2022/0199429), Osenbach et al. (“Osenbach” US 2022/0216127), Rawlings et al. (“Rawlings” US 2019/0393118), and Stathakis et al. (“Stathakis” US 2018/0374715).
Regarding claim 27, Shah discloses a method of manufacturing a semiconductor device (Figures 2B, 4), the method comprising:
forming a boundary layer (202) on a perimeter of a first top surface of a package component (102, see Figure 2B);
dispensing a [material] (110) onto the package component (102) within the perimeter (see Figure 2B, para. [0032]);
placing a heat sink (106) in contact with the boundary layer (202) and the [material] (110, see Figure 2B); and
beginning a cross-linking by curing (Figure 4, 408, para. [0034]) the boundary layer (202) after the placing the heat sink (106, see flow chart of order of processing steps in Figure 4, which shows the curing occurring after the placement of the heat sink, 406), wherein at a beginning of the cross-linking, the boundary layer (202) is cross-linked a substantially similar amount as during the dispensing (since the boundary layer 202 is unaltered further after dispensing until the only curing process, 408, it is obvious that the degree of cross-linking of the boundary layer 202 would substantially be the same since dispensing).
Shah does not disclose that the boundary layer comprises a phase-change material.
Osenbach discloses, however, a “containment ring” (102a) analogous to the claimed boundary layer that comprises a phase-change material (see para. [0080]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Osenbach into the teachings of Shah to include a phase-change material for the boundary layer for the purpose of utilizing a material with higher strength (see Osenbach, para. [0080]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
Shah and Osenbach do not disclose that the material dispensed onto the package component within the perimeter is a liquid metal.
Rawlings discloses, however, a thermal interface material (109), analogous to the “material” 110 of Shah above, formed from a liquid metal (109, para. [0016]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Rawlings into the teachings of Shah and Osenbach to include that the material 110 of Shah is formed from a liquid metal for the purpose of increasing compliance to warping (para. [0013]). Additionally, the selection of a known material based on its suitability for its intended use is prima facie obvious. See MPEP 2144.07.
Shah, Osenbach, and Rawlings do not explicitly teach wherein after the curing the liquid metal is thinner at a center of the liquid metal than at a perimeter of the liquid metal, the perimeter being location within the boundary layer.
Stathakis teaches a boundary layer (104) and a TIM within the boundary layer (see thermally conductive material 326) having a thinner portion at the center portion (see Figure 3) than at a perimeter of the material within the boundary layer (see Figure 3, the thickness of the TIM 326 is greater at its edges than at the center).
It would have been obvious to a person having ordinary skill in the art to incorporate the teachings of Stathakis into the teachings of Shah, Osenbach, and Rawlings to include the different thicknesses of the TIM (the liquid metal of the Shah/Osenbach/Rawlings combination) within the boundary layer in order to further reduce thermal resistance (Stahtakis, para. [0075]).
Regarding claim 28, Shah discloses wherein after the curing (408) the boundary layer (202) is solidified (see para. [0034]).
Regarding claim 29, The combination of Shah, Osenbach, and Rawlings discloses wherein a cross-linked gel is formed at an interface between the boundary layer (202) and the liquid metal (110, liquid metal material incorporated by Rawlings).
Shah does not explicitly disclose a cross-linked gel at the interface of elements 202/110. However, the instant specification does not provide any mechanism by which the cross-linked interface is formed other than a curing process, which Shah discloses (para. [0034]). Therefore, a person of ordinary skill in the art would expect that, as Shah provides the curing method and Rawlings and Osenbach provide the phase change and liquid materials, the cross-linking of the boundary layer and the liquid metal would also have occurred.
Regarding claim 30, The combination of Shah, Osenbach, and Rawlings discloses wherein the liquid metal (110, liquid metal material incorporated by Rawlings) contacts the boundary layer (202) after placing the heat sink (106) in contact with the boundary layer (202, see Figure 2B which shows the contact between the material 110 and boundary layer 202).
Regarding claim 31, The combination of Shah, Osenbach, and Rawlings discloses wherein after placing the heat sink (106, Figure 2B), a top surface of the liquid metal (110, liquid metal material incorporated by Rawlings ) is level with a top surface of the boundary layer (202, see Figure 2B).
Regarding claim 33, Shah discloses wherein the liquid metal (110, liquid metal material incorporated by Rawlings) is split into two or more isolated regions (see region of 110 over chip 102, and another portion of material 110 over chip 204, thus is split into two or more isolated regions).
Regarding claim 25, the combinations of teachings of Shah, Osenbach, and Rawlings do not disclose wherein the phase-change material has a melting point above 40 °C.
Honeywell discloses wherein the phase-change material has a melting point above 40 °C (PCM has a phase change temperature of 45°C, page 7).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Honeywell into the teachings of Shah, Osenbach, and Rawlings to include wherein the boundary layer has a glass- transition temperature between about 45 °C and about 60 °C to provide optimal surface wetting at manufacturing temperatures (Honeywell, page 7).
Claim 32 is rejected under 35 U.S.C. 103 as being unpatentable over Shah, Osenbach, Rawlings, and Stathakis as applied to claim 27 above, and further in view of Honeywell (Honeywell Portfolio of Products, Brochure, August 2021).
Regarding claim 32, the combinations of teachings of Shah, Osenbach, and Rawlings do not disclose wherein the phase-change material has a thermal conductivity value of about 5 W/mk or greater and a Young's modulus value of about 10 MPa or less.
Honeywell discloses wherein the phase-change material (page 7) has a thermal conductivity value of about 5 W/mk or greater (page 7 discloses a thermal conductivity of 6.0-8.5 W/mK).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the present invention to incorporate the teachings of Honeywell into the teachings of Shah, Osenbach, and Rawlings to include wherein the phase-change material has a thermal conductivity value of about 5 W/mk or greater for the purpose of high thermal performance (Honeywell, page 7).
While Honeywell and Chee do not explicitly disclose the Young’s modulus of the phase change material, the instant specification discloses that the TIM may be a commercially available Honeywell PCM (para. [0028]). Since Applicant’s disclosure is enabling for this claim, the Honeywell PCM disclosed in the cited brochure would read on the claim limitations, specifically the Young’s modulus being about 10 MPa or less as claimed in claim 32.
Response to Arguments
Applicant’s arguments with respect to claims 1, 21, and 27 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, 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 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Genevieve G Bullard-Connor whose telephone number is (571)270-0609. The examiner can normally be reached Mon-Fri, 9am-5pm.
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/Genevieve G Bullard-Connor/Examiner, Art Unit 2899 /DALE E PAGE/Supervisory Patent Examiner, Art Unit 2899
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