# US 11,445,620 B2 · Method of making printed circuit board structure including a closed cavity with vias > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,445,620 B2 - Document ID: US11445620B2 - Status: Granted - Kind: B2 - Application number: 17/230,584 - Filed: 2021-04-14 - Published: 2021-10-07 - Granted: 2022-09-13 - Earliest claimed: 2017-05-05 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Ki Wook Lee - Web page: https://patentgrep.com/patent/US11445620B2 ## CPC - H05K 3/4697: {having cavities, e.g. for mounting components (H05K3/4691 takes precedence)} - H01Q 1/38: formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142)} - H05K 1/165: {incorporating printed inductors} - H05K 3/4623: {the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards (H05K3/462 takes precedence)} - H05K 3/4655: {by using a laminate characterized by the insulating layer (general-purpose insulating materials H05K1/03, H05K3/4673)} - H01Q 9/0407: {Substantially flat resonant element parallel to ground plane, e.g. patch antenna (dipole H01Q9/285; monopole H01Q9/40)} - H05K 3/0026: {by laser ablation} - H05K 3/0047: {Drilling of holes} - H05K 3/005: {Punching of holes} - H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)} - H05K 3/4038: {Through-connections; Vertical interconnect access [VIA] connections (H05K3/403, H05K3/42 take precedence)} - H05K 3/429: {Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers} - H05K 2201/10098: Components for radio transmission, e.g. radio frequency identification [RFID] tag, printed or non-printed antennas - Y10T 29/49016: Antenna or wave energy "plumbing" making - Y10T 29/5317: Laminated device - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of making a printed circuit board structure including a closed cavity is provided. The method can include the steps of forming a cavity in a core structure of a core layer, laminating each of a top surface and a bottom surface of the core structure with an adhesive layer and a metal layer to prepare a laminate structure and cover the cavity to define a closed cavity. The method also includes forming vias through the laminate structure, and patterning the metal layers in the laminate structure. ## Claims ### Claim 1 A method of making a printed circuit board comprising: providing a printed circuit board structure having an open cavity defined in a core layer; laying a cover layer over the printed circuit board structure so that the cover layer extends over the open cavity to cover the open cavity and define a closed cavity antenna filled with air; laminating a board over the cover layer, the board having at least two layers; forming one or more through bores through the cover layer; and plating the one or more through bores to form one or more vias between a top metal layer of the board and a bottom metal layer of the board. ### Claim 2 (depends on 1) The method of claim 1 wherein the board is a 2-layer board. ### Claim 3 (depends on 1) The method of claim 1 wherein the cover layer is a prepreg layer. ### Claim 4 (depends on 1) The method of claim 1 wherein the cover layer is a no-flow or low-flow adhesive layer. ### Claim 5 (depends on 1) The method of claim 1 wherein the cover layer defines a top wall of the closed cavity. ### Claim 6 (depends on 1) The method of claim 1 wherein forming one or more through bores includes forming the bores with a laser. ### Claim 7 (depends on 1) The method of claim 1 further comprising forming a vent hole between the closed cavity and an outer edge of the printed circuit board to allow air to exit the closed cavity, thereby inhibiting damage to the closed cavity from increased pressure from air in the closed cavity during a heating process. ### Claim 8 (depends on 1) The method of claim 1 wherein the closed cavity antenna is U shaped. ### Claim 9 (depends on 1) The method of claim 1 wherein the closed cavity antenna is coil shaped. ### Claim 10 (depends on 1) The method of claim 1 wherein the closed cavity antenna is a loop antenna. ### Claim 11 A closed-cavity printed circuit board comprising: a printed circuit board structure having an open cavity defined in a core layer; a cover layer over the printed circuit board structure so that the cover layer extends over the open cavity to cover the cavity and define a closed cavity antenna filled with air; a board over the cover layer, the board having at least two layers; one or more through bores through the cover layer; and one or more plated through bores to form one or more vias between a top metal layer of the board and a bottom metal layer of the board. ### Claim 12 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the board is a 2-layer board. ### Claim 13 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the cover layer is a prepreg layer. ### Claim 14 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the cover layer is a no-flow or low-flow adhesive layer. ### Claim 15 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the cover layer defines a top wall of the closed cavity. ### Claim 16 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein forming one or more through bores includes forming the bores with a laser. ### Claim 17 (depends on 11) The closed-cavity printed circuit board of claim 11 further comprising a vent hole between the closed cavity and an outer edge of the printed circuit board to allow air to exit the closed cavity, thereby inhibiting damage to the closed cavity from increased pressure from air in the closed cavity during a heating process. ### Claim 18 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the closed cavity antenna is U shaped. ### Claim 19 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the closed cavity antenna is coil shaped. ### Claim 20 (depends on 11) The closed-cavity printed circuit board of claim 11 wherein the closed cavity antenna is a loop antenna.