# US 10,120,424 B2 · Conductive stress-relief washers in microelectronic assemblies > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,120,424 B2 - Document ID: US10120424B2 - Status: Granted - Kind: B2 - Application number: 15/410,667 - Filed: 2017-01-19 - Published: 2018-07-19 - Granted: 2018-11-06 - Earliest claimed: 2017-01-19 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Hyoung Il Kim - Web page: https://patentgrep.com/patent/US10120424B2 ## CPC - G06F 1/20: Cooling means - G06F 1/184: Mounting of motherboards - H01R 12/7005: {Guiding, mounting, polarizing or locking means; Extractors (for printed circuit boards H05K)} - H01R 12/7076: {for connection between PCB and component, e.g. display} - H01R 12/721: {cooperating directly with the edge of the rigid printed circuits} - H01R 12/73: connecting to other rigid printed circuits or like structures - H05K 1/0204: {using means for thermal conduction connection in the thickness direction of the substrate (H05K1/0207 takes precedence)} - H05K 1/0209: {External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings} - H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion} - H05K 1/092: {Dispersed materials, e.g. conductive pastes or inks} - H05K 1/111: {Pads for surface mounting, e.g. lay-out} - H05K 3/368: {parallel to each other (H05K3/361 takes precedence)} - H10W 40/611: {Bolts or screws} - H05K 1/0203: {Cooling of mounted components (H05K1/0272 takes precedence)} - H05K 1/117: {Pads along the edge of rigid circuit boards, e.g. for pluggable connectors} - H05K 1/144: {Stacked arrangements of planar printed circuit boards} - H05K 2201/041: Stacked PCBs, i.e. having neither an empty space nor mounted components in between - H05K 2201/042: Stacked spaced PCBs; Planar parts of folded flexible circuits having mounted components in between or spaced from each other - H05K 2201/066: Heatsink mounted on the surface of the printed circuit board [PCB] - H05K 2201/10159: Memory - H05K 2201/10325: Sockets, i.e. female type connectors comprising metallic connector elements integrated in, or bonded to a common dielectric support - H05K 2201/10409: Screws - H10W 40/235: {attached to package parts} - H10W 40/60: Securing means for detachable heating or cooling arrangements, e.g. clamps - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H01R: ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Microelectronic device assembly including a component attached to substrate by at least a screw. The screw applies compressive force against a pad of a thermally and electrically conductive material having sufficiently low modulus to mitigate stress in addition to providing a thermal and electrical path between the component and the substrate. In some embodiments, the screw affixes a printed circuit board hosting one or more integrated circuit components to a motherboard, or passive heat sink. The pad may be deformed to assuage stress applied through the screw during assembly of the device and/or as the device experiences thermal cycling, for example associated with intermittent operation. ## Claims ### Claim 1 A microelectronic device assembly, comprising: a first substrate; a second substrate including one or more integrated circuit (IC) components electrically coupled to the second substrate; a screw affixing the second substrate to the first substrate; and an electrically and thermally conductive pad between a head of the screw and a metal feature on the first or second substrate, wherein the pad is deformed by a force maintained by the screw, wherein the pad comprises a material having a hardness below 50 Shore C; wherein the pad comprises a material having a thermal conductivity of at least 1 W/m-K; and wherein the pad comprises a material having a volume resistivity no more than 1.0×104 Ω-cm. ### Claim 2 (depends on 1) The assembly of claim 1, wherein the pad comprises a material having a hardness below 50 Shore A. ### Claim 3 (depends on 1) The assembly of claim 1, wherein the pad comprises a material having a thermal conductivity of at least 30 W/m-K. ### Claim 4 (depends on 1) The assembly of claim 1, wherein the pad comprises a material having a volume resistivity no more than 500 Ω-cm. ### Claim 5 (depends on 1) The assembly of claim 1, wherein the pad has a thickness no greater than 1 mm and an outer diameter (OD) no more than 2 mm. ### Claim 6 (depends on 5) The assembly of claim 5, wherein the pad OD is no larger than an OD of the screw head. ### Claim 7 (depends on 1) The assembly of claim 1, wherein the pad comprises a material having: a hardness no more than 50 Shore A; a thermal conductivity of at least 30 W/m-K; and a volume resistivity no more than 500 Ω-cm. ### Claim 8 (depends on 1) The assembly of claim 1, wherein the pad comprises a material loaded with a conductive filler. ### Claim 9 (depends on 1) The assembly of claim 1, wherein the material comprises silicone and the filler comprises at least one of carbon particles, metal particles, or metal-coated particles. ### Claim 10 (depends on 1) The assembly of claim 1, wherein: the first substrate comprises a first printed circuit board (PCB) including an edge connector socket and a screw mount, the screw mated to the screw mount, and the screw mount electrically coupled to a ground plane of the first PCB; the second substrate comprises a second PCB having: edge connector traces at a first edge of the second PCB mated with the edge connector socket; one or more sockets or lands coupling the one or more IC components to the edge connector traces; and a semicircular indent or through hole at a second edge of the second PCB, the screw extending through the indent or hole, wherein the metal feature comprises an electrically conductive trace adjacent to an edge of the indent or through hole and electrically coupled to a ground plane of the second PCB; wherein the pad comprises an annular washer surrounding the screw that is compressed between the screw head and the electrically conductive trace. ### Claim 11 (depends on 10) The assembly of claim 10, wherein: the one or more IC components comprise a plurality of non-volatile memory ICs; and the edge connector and the screw mount are only physical connections between the first and second substrates. ### Claim 12 (depends on 1) The assembly of claim 1, wherein the first substrate is a metal heat sink and the second substrate is a printed circuit board (PCB). ### Claim 13 An electronic computing device, comprising: a mother board including a screw mount electrically coupled to a ground plane of the motherboard, and an edge connector socket; a solid state drive (SSD) including a plurality of non-volatile memory ICs mounted to a printed circuit board (PCB), the PCB having: edge connector traces at a first edge of the PCB mated with the edge connector socket, the traces coupled to the memory ICs; a semicircular indent or through hole at a second edge of the PCB; and an electrically conductive trace adjacent to an edge of the indent or through hole, and electrically coupled to a ground plane of the PCB; a screw affixing the PCB to the motherboard, the screw passing through the indent or hole; and an annular washer surrounding the screw and located between a head of the screw and the electrically conductive trace, wherein: the ground planes of the PCB and motherboard are electrically coupled through at least the washer; the PCB is thermally coupled to the motherboard through at least the washer; and the washer is elastically deformed between a head of the screw and the PCB; wherein the washer comprises a material having a hardness below 50 Shore C; wherein the washer comprises a material having a thermal conductivity of at least 1 W/m-K; and wherein the washer comprises a material having a volume resistivity no more than 1.0×104 Ω-cm. ### Claim 14 (depends on 13) The device of claim 13, wherein the washer comprises a material loaded with a conductive filler. ### Claim 15 (depends on 14) The device of claim 14, wherein: the loaded material comprises silicone; the filler comprises at least one of carbon particles, metal particles, or metal-coated particles; and the loaded material has: a hardness no more than 50 Shore A; a thermal conductivity of at least 30 W/m-K; and a volume resistivity no more than 500 Ω-cm. ### Claim 16 (depends on 13) The device of claim 13, further comprising: a microprocessor electrically coupled to the motherboard; and a chassis to which the motherboard is mounted.