# US 2019/0172767 A1 · Apparatus and mechanisms for reducing warpage and increasing surface mount technology yields in high performance integrated circuit packages > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0172767 A1 - Document ID: US20190172767A1 - Status: Published application - Kind: A1 - Application number: 16/000,637 - Filed: 2018-06-05 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: Google Inc. - Applicants: Google LLC - Inventors: Woon Seong Kwon; Phillip La; Michael Trent Wise - Web page: https://patentgrep.com/patent/US20190172767A1 ## CPC - H10W 76/47: Solid or gel fillings - H10P 72/0431: {Apparatus for thermal treatment} - H10P 72/0438: {Apparatus for making assemblies not otherwise provided for, e.g. package constructions} - H10W 42/121: {protecting against mechanical damage (H10W76/00, H10W74/00 take precedence)} - H10W 76/40: Fillings or auxiliary members in containers, e.g. centering rings (fillings or auxiliary members for thermal protection or control in containers or encapsulations H10W40/70) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A stiffener apparatus for reducing warpage of an integrated circuit package during heating and cooling are provided. The stiffener apparatus includes an IC substrate configured to receive an IC die on a top side of the IC substrate. The stiffener apparatus includes a primary stiffener ring adhered to the top side of the IC substrate and defining an opening in a region of the IC die such that the primary stiffener ring surrounds the region of the IC die. The primary stiffener ring defines a plurality of grooves. The stiffener apparatus includes a secondary stiffener ring having a plurality of catches configured to engage with the plurality of grooves to removably attach the secondary stiffener ring to the primary stiffener ring on a side of the primary stiffener ring opposite the IC substrate. A method of using a stiffener apparatus during a manufacturing operation is also provided. ## Claims ### Claim 1 A stiffener apparatus for reducing warpage of an integrated circuit (IC) package during heating and cooling, the stiffener apparatus comprising: a primary stiffener ring adhered to a top side of an IC substrate and defining an opening in a region of the IC substrate configured to receive an IC die such that the primary stiffener ring surrounds the region; a secondary stiffener ring configured to removably attach to the primary stiffener ring on a side of the primary stiffener ring opposite the IC substrate. ### Claim 2 (depends on 1) The stiffener apparatus of claim 1, wherein: the primary stiffener ring includes a plurality of steps defined by a region of narrower thickness at a periphery of the primary stiffener ring, each step forming a recess between the primary stiffener ring and the IC substrate; and the secondary stiffener includes a plurality of catches, each catch formed by a protrusion directed inward from near a periphery of the secondary stiffener ring. ### Claim 3 (depends on 2) The stiffener apparatus of claim 2, wherein: the catches are configured to engage with the recesses when the secondary stiffener ring is placed onto the primary stiffener ring and rotated relative to the primary stiffener ring in a plane parallel to the top surface of the IC substrate such that the catches engage with the recesses. ### Claim 4 (depends on 3) The stiffener apparatus of claim 3, wherein the steps are defined at corners of the primary stiffener ring and the catches are defined at corners of the secondary stiffener ring. ### Claim 5 (depends on 3) The stiffener apparatus of claim 3, wherein the secondary stiffener ring defines a plurality of notches along its periphery for receiving a tool to rotate the secondary stiffener ring. ### Claim 6 (depends on 2) The stiffener apparatus of claim 2 wherein: the catches are configured to engage with the recesses when the secondary stiffener ring is placed onto and offset from the primary stiffener ring, and the secondary stiffener ring is moved relative to the primary stiffener ring in a plane parallel to the top surface of the IC substrate. ### Claim 7 (depends on 2) The stiffener apparatus of claim 2, wherein: the catches are configured to engage with the recesses when a force is exerted downward on the secondary stiffener ring in the direction of the primary stiffener ring such that the catches bend outward and around sides of the primary stiffener ring and then snap into the recesses. ### Claim 8 (depends on 1) The stiffener apparatus of claim 1, wherein: the primary stiffener ring includes a magnetic metal or alloy, and the secondary stiffener ring includes a plurality of magnets, each magnet placed in regions of the secondary stiffener ring between the catches. ### Claim 9 (depends on 1) The stiffener apparatus of claim 1, wherein the primary stiffener ring has a height relative to the top surface of the IC substrate that is equal to or less than a height of an IC die relative to the top surface of the IC substrate. ### Claim 10 (depends on 1) The stiffener apparatus of claim 1, wherein the secondary stiffener ring has a thickness in a direction normal to the top surface of the IC substrate that is thicker than a thickness of the primary stiffener ring. ### Claim 11 A method of using a stiffener apparatus during a manufacturing operation, the method comprising: adhering a primary stiffener ring to a top surface of an integrated circuit (IC) substrate; removably attaching a secondary stiffener ring to the primary stiffener ring; mounting the assembly including the IC substrate, the primary stiffener ring, and the secondary stiffener ring to a printed circuit board (PCB); and removing the secondary stiffener ring from the primary stiffener ring. ### Claim 12 (depends on 11) The method of claim 11, wherein mounting the assembly to the PCB includes a reflow soldering process. ### Claim 13 (depends on 11) The method of claim 11, wherein: the primary stiffener ring includes a plurality of steps defined by a region of narrower thickness at a periphery of the primary stiffener ring, each step forming a recess between the primary stiffener ring and the IC substrate; and the secondary stiffener includes a plurality of catches, each catch formed by a protrusion directed inward from near a periphery of the secondary stiffener ring. ### Claim 14 (depends on 13) The method of claim 13, wherein: removably attaching the secondary stiffener ring to the primary stiffener ring includes placing the secondary stiffener ring onto the primary stiffener ring and rotating the secondary stiffener ring relative to the primary stiffener ring in a plane parallel to the top surface of the IC substrate such that the catches engage with the recesses. ### Claim 15 (depends on 14) The method of claim 14, wherein: rotating the secondary stiffener ring includes engaging a tool into a plurality of notches defined along a periphery of the secondary stiffener ring and rotating the secondary stiffener ring using the tool. ### Claim 16 (depends on 13) The method of claim 13, wherein: removably attaching the secondary stiffener ring to the primary stiffener ring includes placing the secondary stiffener ring onto and offset from the primary stiffener ring, and sliding the secondary stiffener ring relative to the primary stiffener ring in a plane parallel to the top surface of the IC substrate such that the catches engage with the recesses. ### Claim 17 (depends on 13) The method of claim 13, wherein: removably attaching the secondary stiffener ring to the primary stiffener ring includes exerting a force on the secondary stiffener ring downward in the direction of the primary stiffener ring such that the catches bend outward and around sides of the primary stiffener ring and then snap into the recesses. ### Claim 18 (depends on 11) The method of claim 11, wherein: the primary stiffener ring includes a magnetic metal or alloy; the secondary stiffener ring includes a plurality of magnets, each magnet placed in regions of the secondary stiffener ring between the catches; and removably attaching the secondary stiffener ring to the primary stiffener ring includes engaging the magnets of the secondary stiffener ring to the primary stiffener ring. ### Claim 19 (depends on 11) The method of claim 11, wherein the primary stiffener ring has a height relative to the top surface of the IC substrate that is equal to or less than a height of an IC die relative to the top surface of the IC substrate. ### Claim 20 (depends on 11) The method of claim 11, wherein the secondary stiffener ring has a thickness in a direction normal to the top surface of the IC substrate that is thicker than a thickness of the primary stiffener ring.