DETAILED ACTION
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 Arguments
RE: the rejection of claim 1 under 35 USC § 103, Applicant argues Czubarow does not disclose an underfill having aluminum oxide and diamond filler particles with a thermal conductivity of 2 W/mK, or an underfill having aluminum oxide filler particles with a thermal conductivity of 10 W/mK. Instead, Czubarow only generically discloses the use of aluminum oxide and diamond, without disclosing any connection between those filler particles (or combination thereof) and thermal conductivity. The art provides no reason to believe that the underfill compositions cited by the Office would have the thermal conductivities cited by the Office.
However, in paragraph [0100], Czubarrow discloses:
Aspect 5. The underfill composition of any one of aspects 1-4 and 6-16, wherein the bulk thermal conductivity of the underfill composition in the cured state is about 0.8 W/mK to about 20 W/mK.
Aspect 6. The underfill composition of any one of aspects 1-5 and 7-16, wherein the filler particles include an oxide.
Aspect 7. The underfill composition of any one of aspects 1-6 and 8-16, wherein the oxide is at least one selected from the group consisting of aluminum oxide.
Aspect 10. The underfill composition of any one of aspects 1-9 and 11-16, wherein the filler particles include diamond.
Accordingly, Czubarow explicitly discloses the use of aluminum oxide and diamond, and the connection between those filler particles and thermal conductivity, contrary to Applicant’s arguments. Further, Czubarow discloses a thermal conductivity of about 0.8 W/mK to about 20 W/mK for an underfill composition including aluminum oxide and also for an underfill composition including aluminum oxide and diamond. Accordingly, it would have been obvious to form an underfill composition having a lower thermal conductivity in the disclosed range of about 0.8 W/mK to about 20 W/mK, such as 2 W/mK and a different underfill composition having a higher thermal conductivity in the disclosed range of about 0.8 W/mK to about 20 W/mK, such as 10 W/mK.
Applicant further argues Czubarow's actually-disclosed compositions show a complex relationship between underfill composition and thermal conductivity. The Office relies on the presence of diamond to reach the "stiffness"-related elements of claim 1. But, based on these examples of Czubarow, a POSITA would expect a composition including diamond to have higher thermal conductivity, the opposite of the relationship required by the Office's rejection.
However, a POSITA would not necessarily expect a composition including diamond to have higher thermal conductivity, as this would also depend on the aluminum oxide content.
Applicant further argues Czubarow, although generically disclosing the inclusion of aluminum oxide, does not disclose any actual example using aluminum oxide, does not describe how aluminum oxide relates to thermal conductivity or stiffness in a filler composition, and does not describe how aluminum oxide might (or might not) interact with diamond (as in the Office's proposed modification) to result in a thermal conductivity or stiffness in a filler composition. In short, the relationship between composition (e.g., material and filler%), thermal conductivity, and stiffness in filler compositions is complex and unpredictable, and the Office has not sufficiently articulated how a POSITA would have achieved the proposed compositions and characteristics (Office Action, pg. 6-7) with a reasonable expectation of success.
However, as stated in MPEP 2158 even “a non-enabling disclosure is prior art for all it teaches for purposes of determining obviousness under 35 U.S.C. 103.” Czubarow discloses underfill compositions with aluminum oxide and/or diamond with a thermal conductivity of about 0.8 W/mK to about 20 W/mK, and this is relied upon for rejecting claim 1.
Applicant further argues although the Office cites Young's moduli of aluminum oxide or diamond as discrete materials, the "thermal conductivity" and "stiffness" of amended claim 1 are thermal conductivities and stiffnesses of the filler and the resin together (as the thermal interface materials).
However, claim 1 does not include that the stiffnesses are stiffnesses of the filler and the resin “together.” Accordingly, “together” cannot be given patentable weight. Further, the reference US20240170511A1 (“Komai”) discloses the sealing resin includes a base material and a reinforcing material having a Young's modulus or breaking strength higher than that of the base material, [0012]. Accordingly, under a broad reasonable interpretation, “a stiffness of the first thermal interface material” and “a stiffness of the second thermal interface material” as in claim 1 refer to a stiffness (Young’s modulus) of a portion of the first or second thermal interface material.
Applicant argues Czubarow is not enabled, arguing The Office cites several disclosures of Czubarow relating to thermal conductivity, such as a TC of "10 W/mk" to address claim 1 (Office Action, 6) and a TC in a "range of 10 W/mK to 20 W/mK" to address claim 8 (Office Action, 17). But these teachings, although provided generically in Czubarow, are not enabled and therefore do not demonstrate obviousness. The compositions manufactured in Czubarow only have thermal conductivities less than 2 W/mK, as shown in Tables 1-3. Czubarow does not disclose or suggest how to achieve TC in a "range of 10 W/mK to 20 W/mK," and a POSITA would not have had a reasonable expectation of success in achieving this TC based on Czubarow, let alone achieving these TCs in conjunction with the aluminum oxide/diamond compositions proposed by the Office.
However, Tables 1-3 in Czubarow are examples, with Tables 2-3 being examples in accordance with Czubarow’s invention (see [0095] Czubarow). These Tables do not disclose aluminum oxide were used filler particles. Additionally, as stated in MPEP 2158 even “a non-enabling disclosure is prior art for all it teaches for purposes of determining obviousness under 35 U.S.C. 103.”
Furtermore, Czubarow discloses The filler particles included in the disclosed underfill composition are generally configured to allow the underfill composition to have the following properties: (2) a bulk thermal conductivity that is greater than about 0.8 W/mK when in the cured state, [0051]. In some examples, the filler particles can include an oxide, a nitride and/or diamond, [0052]. Czubarow further discloses In some examples, the filler particles have a bulk thermal conductivity of greater than about 20 W/mK, [0066]. Accordingly, a POSITA would have understood that the filler particles control bulk thermal conductivity, to result in a bulk thermal conductivity greater than about 0.8 W/mK. With filler particles having a bulk thermal conductivity of 20 W/mK, a POSITA would have understood the thermal conductivity of the underfill composition would approach 20 W/mK as the percent volume of the filler particles approaches 100%. Accordingly, Czubarow is considered enabled.
Applicant argues The rejection of claim 2 is inconsistent with Czubarow's teachings. In Czubarow's full disclosed compositions that include diamond, the diamond has a higher vol% than oxides. Thus, a POSITA following Czubarow would not have found it obvious to modify Zhou to have "an amount of the filler in the second thermal interface material [] greater than an amount of the filler in the first thermal interface material," as recited in amended claim.
However, in the proposed modification for claim 2, diamond does not necessarily have a lower %vol than aluminum oxide for any underfill composition. In the proposed modification for claim 2, only the filler % volume (which includes aluminum oxide and/or diamond) is modified.
Applicant argues The proposed modification used to reject claim 19 would not have been obvious. Applicant further argues this modification is unmotivated and would not have been obvious. Nakamura discloses only a target range ("30% to 90%"), without disclosing any difference in performance or characteristics between 30% and 90%. Nakamura, [0137]. A POSITA would have had no reason to make one layer 30% and another layer 90%, because Nakamura discloses no different in characteristics therebetween. For example, Nakamura provides no reason to believe that a 30% layer would provide a different thermal conductivity than a 90% layer (as discussed in the cited [0041] of Luo), and therefore would have had no reason to vary the volume% as proposed by the Office.
However, the rejection of claim 19 is based on the primary reference Zhou, and also on the secondary reference Luo. Luo renders obvious making underfill compositions different under an obvious to try rationale, see MPEP 2143. Nakamura discloses an underfill composition having a filler content of 30% by volume to 90% by volume to improve thermal conductivity. Accordingly, selecting a filler content of 30% for the first and second underfill layers in Zhou would improve thermal conductivity for the first and second underfill layers in Zhou, and selecting a filler content of 90% for the third and fourth underfill layers in Zhou would also improve thermal conductivity for the third and fourth underfill layers in Zhou.
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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 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.
Claim(s) 1-2, 6, 9-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over US20160035648A1 (“Zhou”) in view of US20130119527A1 (“Luo”), further in view of US20150252217A1 (“Czubarow”).
RE: Claim 1, Zhou discloses A semiconductor package (100 in FIG. 1), comprising:
a substrate (120 or 102b) including a plurality of vias (120 includes vias, [0012]; FIG. 1 shows 102b includes vias 110);
a first chip stack on the substrate, the first chip stack including a plurality of first semiconductor chips (bottommost 102a and second 102a from the bottom as shown in Annotated FIG. 1 below) sequentially stacked on the substrate;
a second chip stack on the first chip stack, the second chip stack including a plurality of second semiconductor chips (third 102a and fourth 102a from the bottom as shown in Annotated FIG. 1 below) sequentially stacked on the first chip stack;
a plurality of first thermal conductive layers (115 under the bottommost 102a, 115 over the bottommost 102a as shown in Annotated FIG. 1 below), a first one of the plurality of first thermal conductive layers (115 under the bottommost 102a, hereinafter “first underfill layer”) between the substrate and the first chip stack, and at least a second one (115 over the bottommost 102a, hereinafter “second underfill layer”) of the plurality of first thermal conductive layers between first semiconductor chips that are adjacent to each other; and
a plurality of second thermal conductive layers (115 under third 102a from the bottom, 115 over third 102a from the bottom as shown in Annotated FIG. 1 below), a first one of the plurality of second thermal conductive layers (115 under third 102a from the bottom, hereinafter “third underfill layer”) between the first chip stack and the second chip stack, and at least a second one of the plurality of second thermal conductive layers (115 over third 102a from the bottom, hereinafter “fourth underfill layer”) between second semiconductor chips that are adjacent to each other,
wherein the first thermal conductive layers include a first thermal interface material (115 includes underfill material based on its thermal conductivity, [0014], accordingly the first and second underfill layers would have thermal conductive interface material interfacing with 102),
wherein the second thermal conductive layers include a second thermal interface material (115 includes underfill material based on its thermal conductivity, [0014] accordingly the third and fourth underfill layers would have thermal conductive interface material interfacing with 102).
Zhou does not explicitly disclose wherein a thermal conductivity of the second thermal interface material is greater than a thermal conductivity of the first thermal interface material, and
wherein a stiffness of the first thermal interface material is greater than a stiffness of the second thermal interface material;
wherein the first thermal interface material and the second thermal interface material each include a filler and a resin.
However, in the same field of endeavor, Luo discloses the same or different underfill materials 160 may be employed between logic die 102 and memory die 108a, and between each of memory dice 108a through 108d, [0041]. Accordingly, before the effective filing date of the claimed invention, there was a need to determine if the material of the third and fourth underfill layers should be different or the same relative to the material of the first and second underfill layers.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers to have a different material from that of the first and second underfill layers as this would have been obvious to try since different materials is one solution for materials in underfill layers identified by Luo and this would have had a reasonable expectation of success, see MPEP 2143.
In the same field of endeavor, Czubarow discloses the uncured underfill composition generally includes an epoxy resin, a curing agent and a plurality of filler particles, [0011] and that the filler particles can include an oxide, a nitride and/or diamond [0052].
Czubarow further discloses the filler particles included in the underfill composition are made of an oxide. In some instances, the oxide can be a metal oxide. In some examples, the oxide can include, but is not limited to, aluminum oxide, [0023].
Czubarow further discloses the disclosed underfill composition in an uncured state can achieve a superior fluidity value at a bond line of about 20 microns or less and still have a superior bulk thermal conductivity in the cured state, [0010].
Czubarow further discloses wherein the bulk thermal conductivity of the underfill composition in the cured state is about 0.8 W/mK to about 20 W/mK, [0100].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the first and second underfill layers 115 to have an underfill composition including epoxy resin, aluminum oxide, and diamond filler particles and with a lower thermal conductivity in the disclosed range of about 0.8 W/mK to about 20 W/mK, such as 2 W/mK as taught by Czubarow in order to obtain a superior bulk thermal conductivity in these underfill layers as further taught by Czubarow.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers 115 to include an underfill composition with aluminum oxide filler particles and with a higher thermal conductivity in the disclosed range of about 0.8 W/mK to about 20 W/mK, such as 10 W/mK as taught by Czubarow in order to obtain a superior bulk thermal conductivity in these underfill layers as further taught by Czubarow.
As a result, a thermal conductivity of the thermal interface material / underfill composition in the third and fourth underfill layers 115 would be greater than a thermal conductivity of the thermal interface material / underfill composition in the first and second underfill layers 115.
Further, the reference US 20200294934 A1 (“Ono”) discloses that aluminum oxide has a Young’s modulus of 350 to 390 GPa, [0021].
The reference US 20120257647 A1 (“Shu”) discloses that diamond has a Young’s modulus of 1220 GPa, [0033].
The reference US 20080280383 A1 (“Wang”) discloses Young's modulus is a measure of material stiffness, [0026].
As a result, a stiffness of the diamond in the first and second underfill layers would be greater than a stiffness of the aluminum oxide in the third and fourth underfill layers and therefore a stiffness of a portion of the material in the first and second underfill layers would be greater than a stiffness of a portion of the material in the third and fourth underfill layers.
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Annotated FIG. 1 of Zhou
RE: Claim 2, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, wherein
an amount of the filler in the second thermal interface material is greater than an amount of the filler in the first thermal interface material (Czubarow discloses the filler particles included in the underfill composition has a bimodal particle size distribution and are a blend of first and second populations of particle sizes that have respective D50 particle size distributions of about 0.5 microns and about 2.5 to about 3.0 microns. In some examples, where the total volume of the underfill composition sums to a volume fraction of 100%, the first population of filler particles can have a volume fraction of about 5% to about 10%, alternately about 2% to about 7%, alternately about 7% to about 35%, alternately about 10% to about 20% and the second population of particles can have a volume fraction of about 7% to about 20%, alternately about 10% to about 20%, alternately about 7% to about 35%, [0019]; Thus, there was a need to select volume fractions for the first and second population of particles before the effective filing date of the claimed invention.
It would have been obvious to try using a volume fraction of 10% for the first population and 10% for the second population of filler particles in the first and second underfill layers as these are solutions for volume fractions of filler particles for an underfill composition identified by Czubarow and these would have had a reasonable expectation of success, see MPEP 2143. As a result, the combined volume fraction for the filler particles in the first and second underfill layers would be 10%+10% = 20%.
It would have been further obvious to try using a volume fraction of 35% for the first population and 35% for the second population of filler particles in the third and fourth underfill layers as these are solutions for volume fractions of filler particles for an underfill composition identified by Czubarow and these would have had a reasonable expectation of success, see MPEP 2143. As a result, the combined volume fraction for the filler particles in the first and second underfill layers would be 35%+35% = 70%. Therefore, the amount of the filler particles in the third and fourth underfill layers would be greater than the amount of the filler particles in the first and second underfill layers).
RE: Claim 6, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, wherein
a thermal conductivity of the first thermal interface material is in a range of 2 W/mK to 5 W/mK (As modified, a thermal conductivity of the thermal interface material / underfill composition in the first and second underfill layers would be 2 W/mK ), and
a thermal conductivity of the second thermal interface material is in a range of 10 W/mK to 15 W/mK (As modified, a thermal conductivity of the thermal interface material / underfill composition in the third and fourth underfill layers would be 10 W/mK).
RE: Claim 9, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, wherein
the substrate is a silicon wafer (Zhou teaches 102 are each formed from silicon, [0015]), and
each of the first semiconductor chips and second semiconductor chips is a memory chip (Zhou teaches 102a provide data storage (e.g., DRAM dies), [0015] and are therefore each 102a is considered a memory chip).
RE: Claim 10, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, further comprising a molding layer (In Zhou,132) on the substrate, the molding layer covering the first chip stack and the second chip stack (FIG. 1 shows 132 covering all 102a; Zhou teaches 132 (e.g., an epoxy mold compound) surrounds the first semiconductor dies 102 a, [0016]).
RE: Claim 11, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, further comprising
a plurality of chip terminals (In Zhou,112), each of the plurality of chip terminals between a corresponding one of
the substrate and the first chip stack (FIG. 1 shows 112 between all 102a and 120 or 102b),
first semiconductor chips that are adjacent to each other (FIG. 1 shows 112 between all adjacent 102a),
the first chip stack and the second chip stack (FIG. 1 shows 112 between all adjacent 102a), or
second semiconductor chips that are adjacent to each other (FIG. 1 shows 112 between all adjacent 102a),
wherein lateral surfaces of the chip terminals are in contact with a corresponding one of the first thermal conductive layers or the second thermal conductive layers (115 electrically isolates 112, [0014]; FIG. 1 shows lateral surfaces of 112 in contact with corresponding first, second, third, fourth underfill layers 115).
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou in view of Luo, further in view of Czubarow as applied to claim 2, further in view of US20180247910 A1 (“Jin”).
RE: Claim 3, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 2, wherein the filler includes aluminum oxide or aluminum nitride (As modified, each of the first, second, third, and fourth underfill layers include aluminum oxide filler particles).
The combination of Zhou, Luo, Czubarow does not explicitly disclose:
wherein an amount of the aluminum oxide or the aluminum nitride in the second thermal interface material is greater than an amount of the aluminum oxide or the aluminum nitride in the first thermal interface material.
However, Czubarow discloses an amount of the filler particles that can be included in the underfill composition can be about 30% by weight to about 80% by weight, alternately about 50% by weight to about 70% by weight based on the total weight of the composition, [0021].
Accordingly it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the first and second underfill layers 115 to include an underfill composition containing a lower filler amount by weight in the range 30% by weight to about 80% by weight such as 30% to 60% by weight as taught by Czubarow in order to obtain a superior bulk thermal conductivity in these underfill layers as further taught by Czubarow.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers 115 to include an underfill composition containing a higher filler amount by weight in the range 30% by weight to about 80% by weight such as 70% to 80% by weight as taught by Czubarow in order to obtain a superior bulk thermal conductivity in these underfill layers as further taught by Czubarow.
In the same field of endeavor, Jin discloses the resin composition contains the inorganic filler at high concentration as described above, so that cured product 42 has high thermal conductivity, [0035].
Jin further discloses the inorganic filler contains preferably a metal oxide or a metal nitride, more preferably at least any one of alumina, aluminum nitride, and magnesium oxide, [0066].
Jin further discloses The inorganic filler containing alumina remarkably increases the thermal conductivity of cured product 42 and the heat dissipation of semiconductor 1 because alumina has a coefficient of thermal conductivity of as high as 30 W/mk. A content proportion of alumina ranges preferably from 50% by mass to 95% by mass, more preferably from 70% by mass to 95% by mass relative to a whole resin composition, [0066].
Jin further discloses Cured product 42 obtained through thermal curing of the resin composition preferably has a coefficient of thermal conductivity of 1.0 W/mk or more, [0087]. The coefficient of thermal conductivity of cured product 42 is preferably 10 W/mK or less, [0087].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the first and second underfill layers 115 to include an underfill composition containing a lower alumina % mass in the range 50% by mass to 95% by mass such as 50% to 60% by mass as taught by Jin in order to ensure the first and second underfill layers have a high thermal conductivity as taught by Jin.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers 115 to include an underfill composition containing a higher alumina % mass in the range 70% by mass to 95% such as 70% to 95% by mass as taught by Jin in order to ensure the third and fourth underfill layers have a high thermal conductivity as taught by Jin.
As a result, an amount of the aluminum oxide in the third and fourth underfill layers would be greater than an amount of the aluminum oxide in the first and second underfill layers 115.
Claim(s) 4-5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou in view of Luo, further in view of Czubarow, further in view of JP2019052316A (“Nakamura”).
RE: Claim 4, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 2, wherein
an amount of the filler in the first thermal interface material is in a range of 20 vol% to 50 vol% (As modified, the volume fraction of the filler particles in the first and second underfill layers is 20%).
The combination of Zhou, Luo, Czubarow does not explicitly disclose an amount of the filler in the second thermal interface material is in a range of 80 vol% to 97 vol%.
However, in the same field of endeavor, Nakamura discloses There is no particular limitation on the content in the case where the resin composition for mold underfill contains an inorganic filler, and it is 30% by volume to 90% by volume in the total amount of the resin composition for mold underfill from the viewpoint of fluidity and strength, pg. 30, lines 21-23.
Nakamura further discloses If the content of the inorganic filler in the resin composition for mold underfill is 30% by volume or more, properties such as the thermal expansion coefficient, thermal conductivity, and elastic modulus of the cured product tend to be further improved, pg. 30, lines 25-27.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to increase the amount of the filler in the third and fourth underfill layers to 90% as taught by Nakamura in order to further improve thermal conductivity as further taught by Nakamura.
RE: Claim 5, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 2, wherein
an amount of the filler in the first thermal interface material is in a range of 20 vol% to 50 vol% (As modified, the volume fraction of the filler particles in the first and second underfill layers is 20%).
The combination of Zhou, Luo, Czubarow does not explicitly disclose an amount of the filler in the second thermal interface material is in a range of 90 vol% to 92 vol%.
However, in the same field of endeavor, Nakamura discloses There is no particular limitation on the content in the case where the resin composition for mold underfill contains an inorganic filler, and it is 30% by volume to 90% by volume in the total amount of the resin composition for mold underfill from the viewpoint of fluidity and strength, pg. 30, lines 21-23.
Nakamura further discloses If the content of the inorganic filler in the resin composition for mold underfill is 30% by volume or more, properties such as the thermal expansion coefficient, thermal conductivity, and elastic modulus of the cured product tend to be further improved, pg. 30, lines 25-27.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to increase the amount of the filler in the third and fourth underfill layers to 90% as taught by Nakamura in order to further improve thermal conductivity as further taught by Nakamura.
Claim(s) 7-8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou in view of Luo, further in view of Czubarow, further in view of US 20040224163A1 (“Tobita”).
RE: Claim 7, the combination of Zhou, Luo, Czubarow discloses The semiconductor package of claim 1, further comprising:
a third chip stack on the second chip stack, the third chip stack including a plurality of third semiconductor chips sequentially stacked on the second chip stack (Zhou discloses although the assembly 100 includes six dies stacked on the interposer 120, in other embodiments the assembly 100 can include fewer than six dies (e.g., two dies, three dies, four dies, or five dies) or more than six dies (e.g., eight dies, twelve dies, sixteen dies, thirty-two dies, etc.), [0015]; Accordingly, with twelve dies, there would be a third stack of die including the uppermost 102a in FIG. 1 and six additional dies sequentially stacked on the second stack including the second semiconductor chips in Annotated FIG. 1); and
a plurality of third thermal conductive layers, a first one of the plurality of third thermal conductive layers between the second chip stack and the third chip stack, and at least a second one of the plurality of third thermal conductive layers between third semiconductor chips that are adjacent to each other (Zhou discloses The semiconductor dies 102 can be at least partially encapsulated in a dielectric underfill material 115. The underfill material 115 can be deposited or otherwise formed around and/or between the semiconductor dies 102, [0014]; Accordingly, a plurality of third conductive layers 115 would include one 115 between the second chip stack and the third stack and other layers 115 between adjacent dies 102 in the third stack),
wherein the third thermal conductive layers include a third thermal interface material (Zhou discloses underfill material 115 can be selected based on its thermal conductivity to enhance heat dissipation through the semiconductor dies 102, [0014]; Accordingly, 115 would include a thermally conductive interface with dies 102).
The combination of Zhou, Luo, Czubarow does not explicitly disclose wherein the third thermal interface material includes a carbon fiber.
However, in the same field of endeavor, Luo discloses the same or different underfill materials 160 may be employed between logic die 102 and memory die 108a, and between each of memory dice 108a through 108d, [0041]. Accordingly, before the effective filing date of the claimed invention, there was a need to determine if the material of the third conductive layers 115 should be different or the same relative to the first and second underfill layers.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the plurality of third conductive layers 115 to have a different material from that of the first, second, third, fourth underfill layers as this would have been obvious to try since different materials is one solution for materials in underfill layers identified by Luo and this would have had a reasonable expectation of success, see MPEP 2143.
Further, Czubarow discloses the uncured underfill composition generally includes an epoxy resin, a curing agent and a plurality of filler particles, [0011].
In the same field of endeavor, Tobita discloses a thermally-conductive epoxy resin molded article comprising an epoxy resin having molecular chains that contain an azomethine group (—CH=N—). The molded article has a thermal conductivity in the range of 0.5 to 30 W/(m·K), [0008].
Tobita further discloses A suitable amount of thermally-conductive filler can be mixed into the epoxy resin composition in order to improve the thermal conductivity of the thermally-conductive epoxy resin molded article. Examples of thermally-conductive filler include metals, metal oxides, metal nitrides, metal carbides, metal hydroxides, metal-coated resins, carbon fibers [0033].
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the underfill layers 115 in the third chip stack to include the thermally conductive epoxy resin molded article composition including carbon fibers with a thermal conductivity in the range 10 W/(m·K) to 20 W/(m·K) as taught by Tobita in order to improve the thermal conductivity of these layers.
RE: Claim 8, the combination of Zhou, Luo, Czubarow, Tobita discloses The semiconductor package of claim 7, wherein a thermal conductivity of the third thermal interface material is in a range of 10 W/mK to 20 W/mK (As modified, the thermal conductivity of the underfill layers in the third chip stack would be in the range 10 W/(m·K) to 20 W/(m·K)).
Claim(s) 19-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhou in view of Luo, and further in view of Nakamura.
RE: Claim 19, Zhou discloses A semiconductor package (100 in FIG. 1), comprising:
a substrate including a plurality of vias (120 or 102b) including a plurality of vias (120 includes vias, [0012]; FIG. 1 shows 102b includes vias 110);
a first chip stack mounted on the substrate, the first chip stack including a plurality of first semiconductor chips (bottommost 102a and second 102a from the bottom as shown in Annotated FIG. 1 below) sequentially stacked on the substrate;
a second chip stack mounted on a top surface of the first chip stack, the second chip stack including a plurality of second semiconductor chips (third 102a and fourth 102a from the bottom as shown in Annotated FIG. 1 below) sequentially stacked on the first chip stack;
a plurality of first thermal conductive layers (115 under third 102a from the bottom, 115 over third 102a from the bottom as shown in Annotated FIG. 1 below), a first one of the plurality of first thermal conductive layers (115 under third 102a from the bottom, hereinafter “third underfill layer”) between the substrate and the first chip stack, and at least a second one of the plurality of first thermal conductive layers (115 over third 102a from the bottom, hereinafter “fourth underfill layer”) between first semiconductor chips that are adjacent to each other, the first thermal conductive layers including a first thermal interface material (115 includes underfill material based on its thermal conductivity, [0014], accordingly the first and second underfill layers would have thermal conductive interface material interfacing with 102);
a plurality of second thermal conductive layers (115 under third 102a from the bottom, 115 over third 102a from the bottom as shown in Annotated FIG. 1 below), a first one of the plurality of second thermal conductive layers (115 under third 102a from the bottom, hereinafter “third underfill layer”) between the first chip stack and the second chip stack, and at least a second one of the plurality of second thermal conductive layers (115 over third 102a from the bottom, hereinafter “fourth underfill layer”) between second semiconductor chips that are adjacent to each other, the second thermal conductive layers including a second thermal interface material (115 includes underfill material based on its thermal conductivity, [0014] accordingly the third and fourth underfill layers would have thermal conductive interface material interfacing with 102); and
a molding layer (132) on the substrate, the molding layer covering the first chip stack and the second chip stack (FIG. 1 shows 132 covering all 102a; Zhou teaches 132 (e.g., an epoxy mold compound) surrounds the first semiconductor dies 102 a, [0016]).
Zhou does not explicitly disclose wherein the first thermal interface material and the second thermal interface material include aluminum oxide,
wherein an amount of the aluminum oxide in the second thermal interface material is greater than an amount of the aluminum oxide in the first thermal interface material.
However, in the same field of endeavor, Luo discloses the same or different underfill materials 160 may be employed between logic die 102 and memory die 108a, and between each of memory dice 108a through 108d, [0041]. Accordingly, before the effective filing date of the claimed invention, there was a need to determine if the material of the third and fourth underfill layers should be different or the same relative to the material of the first and second underfill layers.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers to have a different material from that of the first and second underfill layers as this would have been obvious to try since different materials is one solution for materials in underfill layers identified by Luo and this would have had a reasonable expectation of success, see MPEP 2143.
In the same field of endeavor, Nakamura discloses The resin composition for mold underfill of the present invention preferably contains (E) an inorganic filler. The inorganic filler is not particularly limited as long as it is generally used for a sealing molding material. For example, spherical silica (fused silica etc.), crystalline silica, glass, alumina, pg. 30, lines 7-10.
Alumina is aluminum oxide.
Nakamura further discloses There is no particular limitation on the content in the case where the resin composition for mold underfill contains an inorganic filler, and it is 30% by volume to 90% by volume in the total amount of the resin composition for mold underfill from the viewpoint of fluidity and strength, pg. 30, lines 21-23.
Nakamura further discloses If the content of the inorganic filler in the resin composition for mold underfill is 30% by volume or more, properties such as the thermal expansion coefficient, thermal conductivity, and elastic modulus of the cured product tend to be further improved, pg. 30, lines 25-27.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the first and second underfill layers 115 to include an underfill composition containing 30% aluminum oxide by volume as taught by Nakamura in order to improve thermal conductivity as further taught by Nakamura.
It would have been further obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the third and fourth underfill layers 115 to include an underfill composition containing 90% aluminum oxide by volume as taught by Nakamura in order to improve thermal conductivity as further taught by Nakamura.
As a result, an amount of the aluminum oxide in the third and fourth underfill layers would be greater than an amount of the aluminum oxide in the first and second underfill layers 115.
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Annotated FIG. 1 of Zhou
RE: Claim 20, the combination of Zhou, Luo, Nakamura discloses The semiconductor package of claim 19, wherein
the amount of the aluminum oxide in the first thermal interface material is in a range of 20 vol% to 50 vol% (As modified, the first and second underfill layers 115 have an aluminum oxide content of 30% by volume), and
the amount of the aluminum oxide in the second thermal interface material is in a range of 80 vol% to 97 vol% (As modified, the third and fourth underfill layers 115 have an aluminum oxide content of 90% by volume).
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 MICHAEL ANGUIANO whose telephone number is (703)756-1226. The examiner can normally be reached Monday through Friday.
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/MICHAEL ANGUIANO/Examiner, Art Unit 2899
/Brent A. Fairbanks/Supervisory Patent Examiner, Art Unit 2899
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