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 .
Status of Claims
This action is responsive to the amendment and remarks filed 7/6/26. Claims 1, 3, 13 and 19 have been amended. Claims 1–20 are pending and have been examined.
The rejections of claims 1–4, 9, 11–14 and 16–20 under 35 U.S.C. 102(a)(1) over Singh, and of claims 5–8, 10 and 15 under 35 U.S.C. 103 over Singh alone or in view of Parida or Joshi, are withdrawn for the reasons set forth in the Response to Arguments below. The objection to claim 3 is withdrawn in view of the amendment.
Claim Objections
Claim 20 is objected to because of the following informality: claim 20 recites "the at least one baseplates cooling channel." For consistency with the antecedent recitation "at least one baseplate cooling channel," the recitation should read "the at least one baseplate cooling channel." Appropriate correction is required.
Claim Interpretation
The following interpretations are applied under the broadest reasonable interpretation consistent with the specification. See MPEP 2111.
"Baseplate." The term is given its ordinary meaning of a plate that supports the components mounted upon it. The specification describes an embodiment in which the baseplate is a finned, low-thermal-impedance structure (¶0058), but claims 1, 13 and 19 recite no fins and no thermal property, and that embodiment is not read into those claims. Claims 8 and 14 separately recite a "low thermal impedance baseplate," which is addressed below.
"Onto." The specification uses "onto" for fluid that is brought into contact with the semiconductor die (¶0033–0034, ¶0059). A fluid in direct contact with the die is directed onto it.
"Channel." The term is given its ordinary meaning of a passage through which fluid is conveyed. The specification's inlet, outlet and cooling channels are passages that carry the fluid to, over and from the die and the baseplate (¶0033–0034) and are not limited to any particular geometry or to a fully enclosed conduit. A nozzle opening that conveys fluid to a surface, an outlet connection that conveys fluid away, and a gap through which fluid flows over a surface are each a channel.
"So as to transfer heat away from the semiconductor die and from the baseplate so as to cool the baseplate assembly." These recitations describe the function performed by the recited flow system. They are given weight and are met by a flow system that performs the recited function. See MPEP 2114.
"Low thermal impedance baseplate" (claims 8, 14). The specification describes this as a baseplate in contact with the cooling fluid so that heat passes to the fluid without intervening thermal interface material, exemplified by a plate with cooling structures machined into it (¶0058). The term is interpreted as a baseplate having a surface in direct contact with the cooling fluid.
"Single continuous flow path" (claims 4, 16, 20). The specification describes the fluid leaving the die and proceeding to the baseplate along one path (¶0035–0036). The term is interpreted as a flow path along which the same fluid proceeds from the region of the die to the region of the baseplate without an intervening separate supply; it does not require the path to be enclosed along its length.
Claim Rejections – 35 U.S.C. § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1–3, 9, 13, 14, 16, 17 and 19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Quon et al. (US 5,448,108, hereinafter "Quon").
Claim 1
Regarding claim 1, Quon discloses a thermal management system (a power module 10 cooled by flowing dielectric liquid, col. 2, ll. 9–13, FIG. 1), comprising:
a baseplate assembly including a baseplate (base plate 24, col. 2, ll. 24–28) defining an upper baseplate surface (the surface of base plate 24 that supports printed wiring board 28, col. 2, ll. 27–30) and a semiconductor die (dies 30, 32, 34, col. 2, ll. 31–32) defining an upper semiconductor surface (the exposed front faces of the dies, which face away from board 28 and are flushed by the dielectric liquid, col. 2, ll. 31–36; col. 3, ll. 7–8), the semiconductor die being arranged on the baseplate such that the upper semiconductor surface is spaced apart from the upper baseplate surface (the dies are mounted on the front of printed wiring board 28, which is in turn supported by base plate 24, col. 2, ll. 27–32; the board is interposed between the plate and the dies so that the die surfaces lie spaced from the plate surface, FIG. 1); and
a flow system (plenum 14, inlet connection 16, nozzle hole groups 18, 20 and 27, and outlet connection 22, col. 2, ll. 13–27) including a first flow path (the flow from nozzle groups 18 and 20 across dies 30–40 to outlet 22, col. 2, ll. 18–23 and 33–38) extending over and in thermal contact with the semiconductor die (the liquid is directed "directly across" the dies with "direct heat transfer" between the dies and the fluid, col. 2, ll. 35–36, 48–53) and a second flow path (the flow from nozzle holes 27 behind base plate 24, col. 2, ll. 26–27) in thermal contact with the baseplate (coolant delivered behind the plate flows against it in the gap held open by standoffs 23, 25, col. 2, ll. 24–27), the flow system including a fluid (the dielectric coolant liquid, col. 3, ll. 2–7) flowing through the first flow path and the second flow path (a single plenum 14 supplies all three nozzle groups from connection 16, col. 2, ll. 15–20, 26–27),
wherein the flow system is configured to direct the fluid over and onto the semiconductor die via the first flow path (nozzle groups 18 and 20 direct the liquid across the dies so that the coolant is "flowing in direct contact with the semiconductor power devices," col. 1, ll. 40–47; col. 2, ll. 33–38) and to the baseplate via the second flow path (nozzle holes 27 "deliver coolant flow behind the baseplate," col. 2, ll. 26–27) so as to transfer heat away from the semiconductor die and from the baseplate so as to cool the baseplate assembly (the coolant absorbs heat from the dies, col. 2, ll. 48–58; the coolant directed against base plate 24, a structural member that carries the heat-generating board, absorbs heat from that plate in the same manner, and the module within housing 12 is cooled by the flowing liquid, col. 1, ll. 5–11; col. 2, ll. 9–13).
As to the recitations "so as to transfer heat away from the semiconductor die and from the baseplate" and "so as to cool the baseplate assembly," these are functional recitations of what the flow system does. They are given weight and are met. Quon's dielectric liquid is a coolant introduced into the housing to absorb heat (col. 1, ll. 5–11; col. 2, ll. 9–13); it is directed against the dies (col. 2, ll. 33–38) and behind base plate 24 (col. 2, ll. 26–27). A flowing coolant in contact with a heated body transfers heat away from it. Quon's base plate carries the wiring board on which the heat-generating dies are mounted (col. 2, ll. 27–32), and the coolant delivered behind it removes heat from it in the same manner it removes heat from the dies. The claimed function is therefore performed by the disclosed structure. See MPEP 2114.As to "baseplate," Quon's base plate 24 is expressly "a structural member which supports printed wiring board 28" (col. 2, ll. 27–29), which is the ordinary meaning of the term as set forth above.
As to "onto," Quon's liquid is in "direct contact" with the dies (col. 1, ll. 40–47), which is the sense in which the specification uses the term.
Claim 2
Regarding claim 2, Quon discloses the thermal management system of claim 1, wherein the first flow path is defined by at least one surface inlet channel that directs the fluid onto the semiconductor die (nozzle hole groups 18 and 20 are openings in the plenum through which the dielectric liquid is delivered directly across the dies, col. 2, ll. 18–21, 33–38; each nozzle hole is a channel that discharges the liquid onto the die surfaces) and at least one surface outlet channel that receives the fluid from the semiconductor die and directs the fluid away from the semiconductor die (outlet connection 22 near the top of housing 12 receives the liquid after it has passed over the dies and passes it out of the housing, col. 2, ll. 21–23; the liquid flows upward across the dies and board to the outlet, col. 1, ll. 60–63; col. 2, ll. 38–47).
Claim 3
Regarding claim 3, Quon discloses the thermal management system of claim 2, wherein the second flow path is defined by at least one baseplate inlet channel that directs the fluid into thermal contact with the baseplate (nozzle holes 27, which deliver coolant flow behind base plate 24, col. 2, ll. 26–27), at least one baseplate cooling channel that directs the fluid over or through the baseplate (the gap between base plate 24 and the back wall 26 of the housing, held open by standoffs 23 and 25, through which the coolant delivered by nozzle holes 27 flows over the rear face of the plate, col. 2, ll. 24–27, FIG. 1), and at least one baseplate outlet channel that receives the fluid from the at least one baseplate cooling channel and directs the fluid away from the baseplate (outlet connection 22, which passes the liquid from the housing, col. 2, ll. 21–23; the liquid in the housing, including that delivered behind the plate, flows upward to the outlet, col. 1, ll. 60–63).
As to "baseplate cooling channel," the gap between the plate and the back wall is a passage bounded on two sides by those members and on its ends by the standoffs, through which the fluid is conveyed over the plate. It is a channel under the interpretation set forth above.
Claim 9
Regarding claim 9, Quon discloses the thermal management system of claim 1, wherein the semiconductor die is directly exposed to the fluid (both the power and control electronics are exposed to the dielectric liquid coolant, col. 3, ll. 7–8; the coolant flows in direct contact with the semiconductor power devices, col. 1, ll. 40–47). Quon discloses that the dies are semiconductor power devices of a power module (col. 1, ll. 5–11; col. 2, ll. 31–32) but does not expressly state that the die is a field effect transistor die. This limitation is addressed under 35 U.S.C. 103 below.
Claim 13
Regarding claim 13, Quon discloses a thermal management system (a power module 10 cooled by flowing dielectric liquid, col. 2, ll. 9–13, FIG. 1), comprising:
a baseplate assembly including a baseplate (base plate 24, col. 2, ll. 24–28) and a semiconductor die (dies 30, 32, 34, mounted on printed wiring board 28 which is supported by base plate 24, col. 2, ll. 27–32); and
a flow system (plenum 14, inlet connection 16, nozzle hole groups 18, 20 and 27, and outlet connection 22, col. 2, ll. 13–27) in thermal contact with the baseplate (nozzle holes 27 deliver coolant flow behind base plate 24, col. 2, ll. 26–27) and the semiconductor die (nozzle groups 18 and 20 deliver the liquid directly across the dies, col. 2, ll. 33–38) and including a fluid configured to flow through the flow system (the dielectric coolant liquid, introduced at connection 16, distributed through plenum 14, and discharged at outlet 22, col. 2, ll. 15–23; col. 3, ll. 2–7),
wherein the flow system is configured to direct the fluid over and onto the semiconductor die (the liquid is directed across the dies and is "flowing in direct contact with the semiconductor power devices," col. 1, ll. 40–47; col. 2, ll. 33–38) and to the baseplate (coolant flow is delivered behind the baseplate, col. 2, ll. 26–27) so as to transfer heat away from the semiconductor die and from the baseplate so as to cool the baseplate assembly (the coolant absorbs heat directly from the dies, col. 2, ll. 48–58; the coolant directed behind base plate 24, which carries the board on which the heat-generating dies are mounted, removes heat from the plate in the same manner; the module within housing 12 is cooled by the flowing liquid, col. 1, ll. 5–11; col. 2, ll. 9–13).
The functional recitations "so as to transfer heat away from the semiconductor die and from the baseplate" and "so as to cool the baseplate assembly" are given weight and are met for the reasons stated with respect to claim 1. See MPEP 2114. The interpretations of "baseplate" and "onto" set forth with respect to claim 1 apply equally to claim 13.
Claim 14
Regarding claim 14, Quon discloses the thermal management system of claim 13, wherein the baseplate is a low thermal impedance baseplate (base plate 24 has its rear face in direct contact with the coolant delivered by nozzle holes 27, with no intervening thermal interface material, col. 2, ll. 24–27; under the interpretation set forth above, a baseplate having a surface in direct contact with the cooling fluid is a low thermal impedance baseplate). Claim 14 is additionally rejected under 35 U.S.C. 103 below.
Claim 16
Regarding claim 16, Quon discloses the thermal management system of claim 14, wherein the flow system includes a single continuous flow path that extends over and is in thermal contact with the semiconductor die and that is in thermal contact with the low thermal impedance baseplate (the liquid delivered by nozzle groups 18 and 20 flows upward across the dies and across printed wiring board 28, which is supported on and in contact with base plate 24, to outlet 22, col. 1, ll. 60–63; col. 2, ll. 27–30, 33–47; this flow proceeds as one path from the dies along the board carried by the plate to the outlet, and is in thermal contact with the plate through the board it flows across).
As to "single continuous flow path," the flow from nozzle groups 18 and 20 to outlet 22 is one path of one fluid, uninterrupted by any separate supply, along which the fluid contacts the dies and then the board mounted on the plate. This is within the interpretation set forth above.
Claim 17
Regarding claim 17, Quon discloses the thermal management system of claim 14, wherein the flow system has at least two flow paths, the at least two flow paths including a first flow path that extends over and is in thermal contact with the semiconductor die (the flow from nozzle groups 18 and 20 across the dies, col. 2, ll. 18–21, 33–38) and a second flow path that is in thermal contact with the low thermal impedance baseplate (the flow from nozzle holes 27 behind base plate 24, col. 2, ll. 26–27).
Claim 19
Regarding claim 19, Quon discloses a method (the cooling of power module 10 by flowing dielectric liquid, col. 1, ll. 5–11; col. 2, ll. 9–13), comprising:
providing a baseplate assembly including a baseplate (base plate 24, col. 2, ll. 24–28) defining an upper baseplate surface (the surface of base plate 24 that supports printed wiring board 28, col. 2, ll. 27–30) and a semiconductor die (dies 30, 32, 34, col. 2, ll. 31–32) defining an upper semiconductor surface (the exposed faces of the dies flushed by the dielectric liquid, col. 2, ll. 31–36; col. 3, ll. 7–8);
arranging the semiconductor die on the baseplate such that the upper semiconductor surface is spaced apart from the upper baseplate surface (the dies are mounted on the front of printed wiring board 28, which is supported by base plate 24, col. 2, ll. 27–32; the board is interposed between the plate and the dies, FIG. 1);
providing a flow system (plenum 14, inlet connection 16, nozzle hole groups 18, 20 and 27, and outlet connection 22, col. 2, ll. 13–27) including a first flow path (the flow from nozzle groups 18 and 20 across the dies to outlet 22, col. 2, ll. 18–23, 33–38) extending over and in thermal contact with the semiconductor die (the liquid passes directly across the dies with direct heat transfer between the dies and the fluid, col. 2, ll. 35–36, 48–53) and a second flow path (the flow from nozzle holes 27 behind base plate 24, col. 2, ll. 26–27) in thermal contact with the baseplate (the coolant flows against the plate in the gap held open by standoffs 23, 25, col. 2, ll. 24–27), the flow system including a fluid (the dielectric coolant liquid, col. 3, ll. 2–7) flowing through the first flow path and the second flow path (a single plenum 14 supplies all nozzle groups from connection 16, col. 2, ll. 15–20, 26–27); and
directing the fluid over and onto the semiconductor die via the first flow path (nozzle groups 18 and 20 direct the liquid across the dies so that it is "flowing in direct contact with the semiconductor power devices," col. 1, ll. 40–47; col. 2, ll. 33–38) and to the baseplate via the second flow path (nozzle holes 27 "deliver coolant flow behind the baseplate," col. 2, ll. 26–27) so as to transfer heat away from the semiconductor die and from the baseplate so as to cool the baseplate assembly (the coolant absorbs heat directly from the dies, col. 2, ll. 48–58; the coolant directed behind base plate 24, which carries the board on which the heat-generating dies are mounted, removes heat from the plate in the same manner; the module within housing 12 is cooled by the flowing liquid, col. 1, ll. 5–11; col. 2, ll. 9–13).
As to the recitations "so as to transfer heat away from the semiconductor die and from the baseplate" and "so as to cool the baseplate assembly," these recite the result of the directing step. They are given weight and are met: Quon's directing of coolant against the dies and behind the base plate removes heat from both for the reasons stated with respect to claim 1. Quon describes the operation of its module with the coolant flowing (col. 2, ll. 48–58; col. 3, ll. 7–8), so each recited step is performed in the ordinary use of the disclosed structure. The interpretations of "baseplate" and "onto" set forth with respect to claim 1 apply equally to claim 19.
Claim Rejections – 35 U.S.C. § 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: determining the scope and content of the prior art; ascertaining the differences between the prior art and the claims at issue; resolving the level of ordinary skill in the pertinent art; and considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim 9 is, in the alternative, rejected under 35 U.S.C. 103 as being unpatentable over Quon in view of Singh et al. (GB 2,526,171 A, hereinafter "Singh").
Regarding claim 9, Quon discloses the system of claim 1 with the semiconductor die directly exposed to the fluid, as set forth above. Quon describes the dies as semiconductor power devices of a power module (col. 1, ll. 5–11; col. 2, ll. 31–32) but does not expressly state that the die is a field effect transistor die.
Singh discloses a power module for a vehicle in which the semiconductor switches on the substrate are packaged MOSFET chipsets (p. 4, ll. 20–32), i.e., field effect transistor dies.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ field effect transistor dies as Quon's semiconductor power devices, as Singh discloses, because Quon's module is a generic power module whose dies are semiconductor power switching devices and the MOSFET is a conventional such device; the selection of a known power switching die for a power module is the use of a known element for its established function with predictable results. See MPEP 2143(I)(A).
Claims 4, 5 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Quon in view of Campbell et al. (US 2011/0103019 A1, hereinafter "Campbell").Claim 4Regarding claim 4, Quon discloses the thermal management system of claim 3, including the surface outlet channel (outlet 22) and the baseplate inlet channel (nozzle holes 27), as set forth above. Quon discloses that the die-side flow from nozzle groups 18 and 20 and the baseplate-side flow from nozzle holes 27 are both supplied from plenum 14 and both discharge through outlet 22 (col. 2, ll. 15–27), i.e., in parallel. Quon does not disclose a common surface outlet channel fluidically connected to the at least one surface outlet channel and to the at least one baseplate inlet channel such that the fluid is configured to flow from the surface outlet channel to the baseplate inlet channel so as to define a single continuous flow path from the first flow path to the second flow path.
Campbell discloses liquid cooling of electronic components in which coolant is delivered first to the high-heat-flux component and the same coolant, having left that component, is then conveyed on to cool other surfaces in series. In the embodiment of FIGS. 3–4B, the open-flow cold plate has no closed loop; the coolant supplied to it exits through orifices 420 that provide direct impingement cooling to the high-heat-flux component and then provides coolant flow for the other immersed components (¶0035–0036). In the embodiment of FIGS. 5–6, the coolant first enters the internal fins 550 of cold plate 500, and after circulating through the fins is discharged through side ports 525 to provide immersion cooling to the components outside the module (¶0044–0045). In the system of FIG. 7, the coolant that flows through the open-flow cold plate is expelled into the enclosure and, as it returns to exit port 715, flows over other heated components and cools them (¶0049). Campbell thus teaches conveying the coolant from the first cooled surface directly to the second cooled surface along one continuous path, so that a single supply serves both surfaces and the effluent from the first is used to cool the second.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Quon's flow system so that the liquid leaving the dies is conveyed to the baseplate inlet, i.e., to connect the die-side outlet to the baseplate-side inlet in series as Campbell teaches, rather than feeding both from the plenum in parallel. Campbell supplies the reason: a single coolant supply is thereby made to serve both the primary cooled surface and the secondary surfaces, and the coolant, having taken heat from the primary surface, retains capacity to cool the lower-flux surfaces downstream (¶0035, ¶0044, ¶0049). Quon itself ranks its surfaces in the same order, identifying the dies as the surfaces from which heat is to be directly extracted and the base as a surface through which heat extraction need not be designed (col. 2, ll. 48–62). Routing the coolest liquid to the dies first and the effluent to the base plate second is the application of Campbell's series arrangement to Quon's two surfaces in accordance with Quon's own priority, with the predictable result that both surfaces are cooled from one supply. See MPEP 2143(I)(A), (C).
Claim 5
Regarding claim 5, Quon in view of Campbell teaches the thermal management system of claim 4. Quon discloses that the flow system is configured to control a flow of the fluid over the semiconductor die such that the fluid flows continuously and unimpeded over the upper semiconductor surface (the nozzle groups are positioned so that the liquid is directed directly across the dies in a generally vertical, upward flow and at increased velocity, col. 1, ll. 57–63; col. 2, ll. 33–38, 48–53; Quon's coolants are single-phase dielectric oils and esters, col. 3, ll. 2–7). Campbell likewise discloses continuous single-phase liquid flow directly over the cooled component (¶0035–0036). The recited "first operational mode" is the ordinary operation of Quon's system as modified.
Claim 20
Regarding claim 20, Quon discloses the method of claim 19 as set forth above, wherein the first flow path is defined by at least one surface inlet channel that directs the fluid onto the semiconductor die and at least one surface outlet channel that receives the fluid from the semiconductor die and directs the fluid away from the semiconductor die (nozzle hole groups 18 and 20; outlet 22; col. 2, ll. 18–23, 33–47, as set forth with respect to claim 2), wherein the second flow path is defined by at least one baseplate inlet channel that directs the fluid into thermal contact with the baseplate, at least one baseplate cooling channel that directs the fluid over or through the baseplate, and at least one baseplate outlet channel that receives the fluid from the at least one baseplate cooling channel and directs the fluid away from the baseplate (nozzle holes 27; the gap between base plate 24 and back wall 26; outlet 22; col. 2, ll. 21–27, as set forth with respect to claim 3). Quon does not disclose that the flow system further includes a common surface outlet channel fluidically connected to the at least one surface outlet channel and to the at least one baseplate inlet channel such that the fluid is configured to flow from the at least one surface outlet channel to the at least one baseplate inlet channel so as to define a single continuous flow path from the first flow path to the second flow path. Campbell teaches conveying the coolant from the first cooled surface to the second cooled surface in series, for the reasons and with the motivation set forth with respect to claim 4, which apply equally to the method of claim 20.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Quon in view of Campbell as applied to claim 4 above, and further in view of Tilton et al. (US 2006/0026970 A1, hereinafter "Tilton").
Regarding claim 6, Quon in view of Campbell teaches the thermal management system of claim 4. Quon's coolants are single-phase dielectric liquids (col. 3, ll. 2–7), and Quon in view of Campbell does not teach that the flow system is configured to control the flow such that, in a second operational mode, the fluid is directed onto the upper semiconductor surface and then remains on the upper semiconductor surface for a predetermined period of time such that the fluid boils.
Tilton discloses evaporative cooling of electronic components in which a dielectric coolant is directed onto the surface from which heat is to be transferred and is maintained as a thin liquid film on that surface so that it evaporates there (¶0001, ¶0004; ¶0069, describing two-phase flow in which the liquid is preferably a thin film on the surface from which heat is to be transferred and the evaporation of the coolant is caused by heat transfer from that surface). Tilton discloses that the cooled surface may be a bare die with the coolant in direct contact with the chip (¶0021–0022, FIGS. 10–11; ¶0092, FIG. 14, "direct cooling on a chip 250"). Tilton teaches that evaporative cooling of the surface provides higher heat flux removal than single-phase liquid cooling (¶0004).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to configure the flow system of Quon as modified by Campbell so that, in a further operational mode, the dielectric liquid directed onto the dies is retained on the die surfaces as a film that boils, as Tilton teaches for a bare die in direct contact with the coolant, in order to obtain the higher heat-flux removal that Tilton attributes to evaporation at the cooled surface (¶0004). Quon already directs a dielectric liquid onto the exposed die faces; Tilton teaches operating such a directly wetted die in the evaporative regime and the reason for doing so. Providing the two regimes as alternative operational modes is the provision of a known cooling regime for its known benefit. See MPEP 2143(I)(C), (G).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Quon in view of Campbell as applied to claim 4 above, and further in view of Zeighami et al. (US 6,704,200 B2, hereinafter "Zeighami").
Regarding claim 7, Quon in view of Campbell teaches the thermal management system of claim 4, including the surface inlet channel (nozzle groups 18 and 20) that directs the fluid onto the die. Quon in view of Campbell does not teach that the flow system further includes at least one heat transfer enhancement arranged on the upper semiconductor surface, the heat transfer enhancement including at least one of microchannels, a porous foam material, or a pin fin array, wherein the surface inlet channel directs the fluid through the heat transfer enhancement.
Zeighami discloses a semiconductor die 12 having a plurality of micro-channels 18 etched into the die's substrate (col. 1, ll. 64–67; col. 4, ll. 14–16, FIG. 2, etch line 18A), through which a cooling fluid is directed from an inlet header 29A (col. 2, ll. 24–27; col. 4, ll. 24–26, 53–55, FIG. 3). Zeighami states that micro-channels etched into the semiconductor substrate were known to provide increased-area cooling of the substrate, the micro-channels forming a series of fins in the substrate that assist in dissipating internally generated heat (col. 1, ll. 31–38), and explains the reason: approximately two-thirds of the thermal resistance between the junction and the cooling fluid is internal to the package, so that directly cooling the die itself is needed to reduce thermal impedance and increase dissipation (col. 1, ll. 20–29, 57–61). Zeighami identifies Fluorinert, a dielectric fluid, among the suitable coolants (col. 2, ll. 46–48).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to etch micro-channels into the exposed faces of Quon's dies, as Zeighami teaches, so that the dielectric liquid directed onto the dies by Quon's nozzle groups 18 and 20 is directed through the micro-channels. Zeighami supplies the reason: micro-channels etched into the die increase the surface area through which heat passes to the fluid and reduce the internal thermal impedance that Zeighami identifies as the dominant resistance (col. 1, ll. 20–38). Quon already directs a dielectric liquid onto the exposed die faces in order to extract heat directly from the dies (col. 1, ll. 40–47; col. 2, ll. 48–53); providing the die faces with the known etched-channel enhancement is the application of a known technique to a known device ready for improvement, with the predictable result of increased heat transfer from the die to the liquid. See MPEP 2143(I)(C), (D). As to Zeighami's sealing plate 24 (col. 2, ll. 16–19), the enhancement taught is the etched channels; the plate is an option Zeighami describes for its pumpless closed loop and is not required to obtain the increased area that motivates the combination.
Claims 8, 10 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Quon in view of Parida et al. (US 2019/0348345 A1, hereinafter "Parida").
Claim 8
Regarding claim 8, Quon discloses the thermal management system of claim 1, wherein the baseplate is a low thermal impedance baseplate (base plate 24 has its rear face in direct contact with the coolant with no intervening interface material, col. 2, ll. 24–27; see the interpretation set forth above). Quon discloses that the fluid is a dielectric coolant liquid, such as polyalphaolefin, silicate ester or silicone (col. 3, ll. 2–7), but does not disclose that the fluid is a dielectric refrigerant.
Parida discloses cooling of a heat-dissipating electronic device with a working fluid and teaches that a dielectric fluid is preferable for use around electronic components, where electrically conductive coolants can pose risks, and identifies as suitable dielectric fluids R1234ze, R134a and R245fa (¶0033), each of which is a refrigerant.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ one of the dielectric refrigerants identified by Parida as the dielectric coolant liquid of Quon. Quon requires a dielectric liquid because the electronics are exposed to it (col. 3, ll. 7–8) and states that any of the widely available dielectric coolant liquids may be used (col. 3, ll. 5–7); Parida identifies the recited refrigerants as dielectric fluids suitable for that use (¶0033). The substitution of one known dielectric coolant for another in a system that expressly admits any such coolant is the simple substitution of one known element for another to obtain predictable results. See MPEP 2143(I)(B).
Claim 10
Regarding claim 10, Quon in view of Parida teaches the thermal management system of claim 1 with the fluid being a hydrofluorocarbon refrigerant (R134a, 1,1,1,2-tetrafluoroethane, and R245fa, 1,1,1,3,3-pentafluoropropane, are hydrofluorocarbons, Parida ¶0033), for the reasons and with the motivation set forth with respect to claim 8.
Claim 15
Regarding claim 15, Quon in view of Parida teaches the thermal management system of claim 13 with the fluid being a dielectric refrigerant (Parida ¶0033), for the reasons and with the motivation set forth with respect to claim 8.
Claims 11, 12 and 18 are rejected, and claim 14 is in the alternative rejected, under 35 U.S.C. 103 as being unpatentable over Quon in view of Gradinger et al. (US 2022/0262707 A1, hereinafter "Gradinger").
Claim 11
Regarding claim 11, Quon discloses the thermal management system of claim 3, including the first flow path over the dies and the second flow path behind the base plate, as set forth above. Quon's single plenum 14 supplies both paths with the same dielectric liquid, which discharges through the common outlet 22 (col. 2, ll. 15–27). Quon does not disclose that the fluid includes a first fluid and a second fluid, that the flow system further includes a surface inlet supply channel configured to supply the first fluid to the first flow path and a baseplate inlet supply channel configured to supply the second fluid to the second flow path, or that the first flow path is not in fluidic communication with the second flow path.
Gradinger discloses the cooling of a power semiconductor module baseplate 10 having power semiconductor devices 14 on its first side 12 (¶0061–0062) by a cooler 38 providing a cooling channel 26 that is fixed to the second side 18 of the baseplate in a sealed manner so that the baseplate closes the channel (¶0052, ¶0069–0070, FIG. 3). The cooling channel carries its own coolant flow 24, which contacts the second side of the baseplate to dissipate heat from it (¶0027, ¶0063, ¶0065). The baseplate carries on its second side integral cooling pins 32, formed with the baseplate by forging, between which the coolant flows in direct contact with the pins (¶0034, ¶0048, ¶0066). Gradinger teaches that the coolant is preferably a liquid and more preferably a mixture of water and glycol (¶0027), and that pin-fin baseplate cooling of this kind provides an especially efficient and homogeneous dissipation of heat from the devices (¶0003–0004, ¶0034).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide Quon's base plate 24 with a sealed, separately supplied cooling channel of the kind Gradinger discloses, in place of the open gap fed from Quon's plenum, so that the base plate is cooled by its own water-glycol coolant flow through a pin-finned channel closed by the plate, while the dies continue to be flushed by the dielectric liquid from Quon's plenum. Gradinger supplies the reason: a sealed, pin-finned baseplate channel with a water-glycol coolant is the preferred and especially efficient way to dissipate heat from a power-module baseplate (¶0003–0004, ¶0027, ¶0034), and Quon's baseplate flow is the part of Quon's system that Quon does not rely upon for heat extraction (col. 2, ll. 58–62), so that substituting Gradinger's more effective baseplate cooling for it is an improvement of that part of Quon's system by a known technique. See MPEP 2143(I)(C), (D). In the resulting system, the dielectric liquid supplied to the dies from Quon's plenum 14 through nozzle groups 18 and 20 is the first fluid supplied through a surface inlet supply channel (inlet connection 16 and plenum 14) to the first flow path, and Gradinger's water-glycol coolant supplied to the sealed baseplate channel is the second fluid supplied through a baseplate inlet supply channel (the inlet of cooler 38) to the second flow path. The two paths are necessarily not in fluidic communication: Quon's die-side liquid must be dielectric because the electronics are exposed to it (col. 3, ll. 7–8), while Gradinger's water-glycol coolant is electrically conductive and is usable only because its channel is sealed from the electronics (¶0027, ¶0052). One of ordinary skill in the art would have kept the two fluids in separate, non-communicating circuits for that reason.
Claim 12
Regarding claim 12, Quon in view of Gradinger teaches the thermal management system of claim 11, wherein the first fluid is different than the second fluid (the dielectric liquid of Quon, col. 3, ll. 2–7, and the water-glycol mixture of Gradinger, ¶0027), for the reasons set forth with respect to claim 11.
Claim 14
Regarding claim 14, Quon discloses the thermal management system of claim 13, as set forth above. To the extent Quon's bare base plate 24 is not considered a low thermal impedance baseplate, Gradinger discloses a power-module baseplate 10 having integral cooling pins 32 formed with it by forging, in direct contact with the coolant, made of copper, aluminum or AlSiC (¶0034, ¶0048, ¶0066), which is a baseplate with cooling structures formed in it and in direct contact with the cooling fluid, i.e., a low thermal impedance baseplate as the specification describes the term (¶0058). It would have been obvious to provide Quon's base plate 24 with Gradinger's integral pin-fin cooling structure for the reasons and with the motivation set forth with respect to claim 11.
Claim 18
Regarding claim 18, Quon discloses the thermal management system of claim 17, including the first flow path over the dies and the second flow path behind the base plate (col. 2, ll. 18–27). Quon does not disclose that the fluid includes a first fluid flowing through the first flow path and a second fluid flowing through the second flow path, the first fluid being different than the second fluid. Gradinger teaches a sealed, separately supplied baseplate cooling channel with a water-glycol coolant, and it would have been obvious to provide Quon's base plate with such a channel while retaining the dielectric liquid for the dies, for the reasons and with the motivation set forth with respect to claim 11, whereby the first fluid (Quon's dielectric liquid) is different than the second fluid (Gradinger's water-glycol mixture).
Response to Arguments
Applicant's arguments filed 7/6/26 with respect to the rejections of claims 1–4, 9, 11–14 and 16–20 under 35 U.S.C. 102(a)(1) as anticipated by Singh, and of claims 5–8, 10 and 15 under 35 U.S.C. 103 over Singh alone or in view of Parida or Joshi, have been fully considered but are moot because the new grounds of rejection set forth above do not rely on Singh for any teaching or matter specifically challenged in the argument. The rejections over Singh are withdrawn. Singh is applied above only as a secondary reference to claim 9 for its disclosure of MOSFET dies, a teaching not addressed in applicant's remarks.
As to the characterization of the interview of June 25, 2026, the Examiner's Interview Summary of record reflects that no agreement was reached as to the merits; the examiner indicated that applicant's arguments would be given further consideration and that further search was required. The rejections set forth above are the result of that search and consideration.
Applicant's remarks regarding the objection to claim 3 have been considered. The objection is withdrawn in view of the amendment. Claim 20 is objected to for the reason set forth above.
Conclusion
Independent claims 1, 13 and 19 were amended to recite that the fluid is directed "over and onto" the semiconductor die. As amended, these claims recite a scope not previously presented: the recitation is not accompanied by the surface inlet and outlet channel structure of claim 2, from which it was drawn, and the resulting claims are therefore neither the originally presented independent claims nor original claim 2. The rejections set forth above are made against the claims as amended and the claims that depend from them.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Joshi et al. (US 2017/0094837 A1), two-phase jet impingement cooling of a target plate coupled to a heat-generating device; Prasher et al. (US 2005/0276014 A1), a cold plate with low- and high-heat-flux channels in series; Romero et al. (US 5,565,705), a power module baseplate having an internal coolant cavity.
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 Examiner Zhengfu J. Feng, whose telephone number is 571-272-2949. The examiner can normally be reached Mon – Fri 10AM -6PM. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, JAYPRAKASH GANDHI, can be reached at 571-272-3740. Information regarding the status of an application may be obtained from Patent Center.
/ZHENGFU J FENG/Primary Examiner, Art Unit 2841 September 16, 2026
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