# US 12,218,031 B2 · Thermal interface material containment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,218,031 B2 - Document ID: US12218031B2 - Status: Granted - Kind: B2 - Application number: 17/568,535 - Filed: 2022-01-04 - Published: 2022-07-07 - Granted: 2025-02-04 - Earliest claimed: 2021-01-04 - Assignees: Infinera Corporation - Applicants: Infinera Corp. - Inventors: John W. Osenbach; Gannon Reichert; Vinh Nguyen - Web page: https://patentgrep.com/patent/US12218031B2 ## CPC - H10W 40/611: {Bolts or screws} - H10W 40/77: Auxiliary members characterised by their shape - H10W 40/226: {characterised by projecting parts, e.g. fins to increase surface area (leadframes for cooling H10W70/461)} - H10W 40/257: {having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh or porous structures (H10W40/254, H10W40/251 take precedence)} - H10W 42/121: {protecting against mechanical damage (H10W76/00, H10W74/00 take precedence)} - H10W 95/00: Packaging processes not covered by the other groups of this subclass - H10W 40/625: {Clamping parts not primarily conducting heat} - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Systems and methods of providing a bare circuit integrated circuit package with a containment ring are described. The bare circuit integrated circuit package may be provided with a substrate connected to a printed circuit board. An integrated circuit may be connected to the substrate. A stiffener ring that surrounds the integrated circuit may be attached to the substrate. A heat sink may be positioned on the stiffener ring and over the integrated circuit such that there is a space between a top of the integrated circuit and a bottom surface of the heat sink. A thermal interface material may be provided to thermally connect the integrated circuit and the heat sink. A containment ring may be positioned between the stiffener ring and the integrated circuit, the containment ring sized and positioned to prevent pumping and/or displacement of the thermal interface material. ## Claims ### Claim 1 A bare circuit integrated circuit package, comprising: a substrate connected to a printed circuit board; an integrated circuit connected to the substrate, the integrated circuit having a top; a stiffener ring attached to the substrate, the stiffener ring surrounding the integrated circuit; a heat sink having a bottom surface that is positioned on the stiffener ring and over the integrated circuit such that there is a space between the top of the integrated circuit and the bottom surface of the heat sink, the heat sink connected to the printed circuit board; a thermal interface material, the thermal interface material having an uncompressed volume and a compressed volume, the compressed volume being a volume of the thermal interface material compressed in the space between the top of the integrated circuit and the bottom surface of the heat sink to thermally connect the integrated circuit and the heat sink; and a containment ring having a first wall and a second wall positioned between the stiffener ring and the integrated circuit, the containment ring sized and positioned such that a gap between the first wall of the containment ring and the integrated circuit has a volume of air of between zero percent and thirty percent smaller than the compressed volume of the thermal interface material. ### Claim 2 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the containment ring has a height that is between 0.05 mm and 1 mm higher than a height of the integrated circuit when connected to the substrate plus the space between the top of the integrated circuit and the bottom of the heat sink. ### Claim 3 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the containment ring is a stepped containment ring having a first step and a second step. ### Claim 4 (depends on 3) The bare circuit integrated circuit package of claim 3, wherein the first step of the stepped containment ring has a first height substantially equal to a height of the integrated circuit when connected to the substrate and the second step having a second height that is between 0.05 mm and 1 mm higher than a height of the integrated circuit when connected to the substrate plus the space between the top of the integrated circuit and the bottom of the heat sink. ### Claim 5 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein when the heat sink is connected to the printed circuit board a force exerted on the stiffener ring is between 7.8 Kgf and 11.8 Kgf. ### Claim 6 (depends on 5) The bare circuit integrated circuit package of claim 5, wherein the space between the top of the integrated circuit and the bottom surface of the heat sink is between 25 μm and 50 μm when the heat sink is connected to the printed circuit board such that the force exerted on the stiffener ring is between 7.8 Kgf and 11.8 Kgf. ### Claim 7 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the thermal interface material is a thermal phase change material. ### Claim 8 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the thermal interface material is a thermal grease. ### Claim 9 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the containment ring is constructed of a compressible and deformable material. ### Claim 10 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the substrate is a multi-layer ball grid array substrate. ### Claim 11 A method of assembling a bare circuit integrated circuit package, comprising: connecting an integrated circuit to a substrate; connecting a stiffener ring to the substrate surrounding the integrated circuit; positioning a containment ring having a first wall and a second wall between the stiffener ring and the integrated circuit, the containment ring sized and positioned such that a gap between the first wall of the containment ring and the integrated circuit has a volume of air of between zero percent and thirty percent of a compressed volume of thermal interface material; applying the thermal interface material to a top surface of the integrated circuit, the thermal interface material having an uncompressed volume and a compressed volume, the compressed volume being a volume of the thermal interface material compressed in a space; and applying a heat sink to compress the thermal interface material and to cover the integrated circuit and the containment ring, the heat sink having a bottom surface that is positioned on the stiffener ring and over the integrated circuit. ### Claim 12 (depends on 11) The method of assembling the bare circuit integrated circuit package of claim 11, wherein the containment ring has a height that is between 0.05 mm and 1 mm higher than a height of the integrated circuit when connected to the substrate plus the space between the top of the integrated circuit and the bottom of the heat sink. ### Claim 13 (depends on 11) The method of assembling the bare circuit integrated circuit package of claim 11, wherein the containment ring is a stepped containment ring having a first step and a second step, and wherein the step of positioning the containment ring includes positioning the first step adjacent to an outer peripheral edge of the integrated circuit. ### Claim 14 (depends on 13) The method of assembling a bare circuit integrated circuit package of claim 13, wherein the first step of the stepped containment ring has a first height substantially equal to a height of the integrated circuit when connected to the substrate and the second step having a second height that is between 0.05 mm and 1 mm higher than a height of the integrated circuit when connected to the substrate plus the space between the top of the integrated circuit and the bottom of the heat sink. ### Claim 15 (depends on 11) The method of assembling a bare circuit integrated circuit package of claim 11, wherein applying the heat sink is defined further as exerting a force on the stiffener ring between 7.8 Kgf and 11.8 Kgf. ### Claim 16 (depends on 15) The method of assembling a bare circuit integrated circuit package of claim 15, wherein the applying the heat sink forms a space between the top of the integrated circuit and the bottom surface of the heat sink between 25 μm and 50 μm. ### Claim 17 (depends on 11) The method of assembling a bare circuit integrated circuit package of claim 11, wherein applying the thermal interface material is defined further as applying the thermal interface material in a solid form, the thermal interface material being a thermal phase change material. ### Claim 18 (depends on 11) The method of assembling a bare circuit integrated circuit package of claim 11, wherein applying the thermal interface material is defined further as applying the thermal interface material in a liquid form, the thermal interface material being a thermal grease. ### Claim 19 (depends on 1) The bare circuit integrated circuit package of claim 1, wherein the integrated circuit includes silicon.