# US 2020/0288570 A1 · Circuit Board with Improved Thermal, Moisture Resistance, and Electrical Properties > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0288570 A1 - Document ID: US20200288570A1 - Status: Published application - Kind: A1 - Application number: 16/359,840 - Filed: 2019-03-20 - Published: 2020-09-10 - Earliest claimed: 2019-03-04 - Assignees: OSI Electronics, Inc. - Applicants: OSI Electronics, Inc. - Inventors: Robert Jung; Konstantine Karavakis - Web page: https://patentgrep.com/patent/US20200288570A1 ## CPC - H05K 1/0326: {containing O} - H05K 3/285: {Permanent coating compositions} - H05K 1/0353: {consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement} - H05K 1/112: {directly combined with via connections} - H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions} - H05K 3/427: {initial plating of through-holes in metal-clad substrates} - H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)} - H05K 2201/0141: Liquid crystal polymer [LCP] - H05K 2201/0145: Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN] - H05K 2201/0191: wherein the thickness of the dielectric plays an important role - H05K 2201/0195: Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure - H05K 2201/0323: Carbon - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract A circuit board with improved reliability and ability to withstand sonication, autoclave sterilization, moisture exposure and high pH solution exposure. The circuit board has a substrate made of a liquid crystal polymer, one or more vias extending through the substrate, conductive traces positioned on surfaces of the substrate, and cover layers made of liquid crystal polymer material positioned over surfaces of the substrate. ## Claims ### Claim 1 A circuit board comprising: a substrate comprising a first liquid crystal polymer and two opposing sides, wherein the first of the two opposing sides defines a first surface layer and wherein the second of the two opposing sides defines a second surface layer; one or more vias extending through the substrate and two opposing sides, wherein each of the one or more vias comprises conductive material; a plurality of conductive traces positioned on at least one of the two opposing sides; a first adhesive positioned on the first surface layer; a second adhesive positioned on the second surface layer; a first cover layer positioned over the first adhesive on the first surface layer, wherein the first cover layer comprises a second liquid crystal polymer; and a second cover layer positioned over the second adhesive on the second surface layer, wherein the second cover layer comprises a third liquid crystal polymer. ### Claim 2 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer is at least one of a partially crystalline aromatic polyesters, a polyester comprising monomer units derived from 4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, a polyester comprising monomer units derived from 2,6-hydroxynaphthoic acid, terephthalic acid and acetaminophen, a polyester comprising monomer units derived from 4-hydroxybenzoic acid, terephthalic acid and 4,4′-biphenol, or a polyester comprising one or more aromatic dicarboxylic acids and alicyclic dicarboxylic acids, one or more aromatic diols, alicyclic diols and aliphatic diols, one or more aromatic hydroxy-carboxylic acids, one or more aromatic thiocarboxylic acids, one or more aromatic dithiols or aromatic dithiophenols, or one or more aromatic hydroxy hydroxylamines or aromatic diamines. ### Claim 3 (depends on 1) The circuit board of claim 1 wherein the second liquid crystal polymer is at least one of a partially crystalline aromatic polyesters, a polyester comprising monomer units derived from 4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, a polyester comprising monomer units derived from 2,6-hydroxynaphthoic acid, terephthalic acid and acetaminophen, a polyester comprising monomer units derived from 4-hydroxybenzoic acid, terephthalic acid and 4,4′-biphenol, or a polyester comprising one or more aromatic dicarboxylic acids and alicyclic dicarboxylic acids, one or more aromatic diols, alicyclic diols and aliphatic diols, one or more aromatic hydroxy-carboxylic acids, one or more aromatic thiocarboxylic acids, one or more aromatic dithiols or aromatic dithiophenols, or one or more aromatic hydroxy hydroxylamines or aromatic diamines. ### Claim 4 (depends on 1) The circuit board of claim 1 wherein the third liquid crystal polymer is at least one of a partially crystalline aromatic polyesters, a polyester comprising monomer units derived from 4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, a polyester comprising monomer units derived from 2,6-hydroxynaphthoic acid, terephthalic acid and acetaminophen, a polyester comprising monomer units derived from 4-hydroxybenzoic acid, terephthalic acid and 4,4′-biphenol, or a polyester comprising one or more aromatic dicarboxylic acids and alicyclic dicarboxylic acids, one or more aromatic diols, alicyclic diols and aliphatic diols, one or more aromatic hydroxy-carboxylic acids, one or more aromatic thiocarboxylic acids, one or more aromatic dithiols or aromatic dithiophenols, or one or more aromatic hydroxy hydroxylamines or aromatic diamines. ### Claim 5 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer, second liquid crystal polymer, and third liquid crystal polymer are a same liquid crystal polymer. ### Claim 6 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer has a thickness in a range of 25 to 75 microns. ### Claim 7 (depends on 1) The circuit board of claim 1 wherein each of the first liquid crystal polymer or second liquid crystal polymer has a thickness in a range of 25 to 75 microns. ### Claim 8 (depends on 1) The circuit board of claim 1 wherein the adhesive covers all of the first surface layer. ### Claim 9 (depends on 8) The circuit board of claim 8 wherein the adhesive covers all of the second surface layer. ### Claim 10 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer has a thickness that is less than a thickness of the second liquid crystal polymer and less than a thickness of the third liquid crystal polymer and wherein the thickness of the second liquid crystal polymer is equal to the thickness of the third liquid crystal polymer. ### Claim 11 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer has a thickness that is more than a thickness of the second liquid crystal polymer and more than a thickness of the third liquid crystal polymer and wherein the thickness of the second liquid crystal polymer is equal to the thickness of the third liquid crystal polymer. ### Claim 12 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer has a thickness that is equal to a thickness of the second liquid crystal polymer and equal to a thickness of the third liquid crystal polymer and wherein the thickness of the second liquid crystal polymer is equal to the thickness of the third liquid crystal polymer ### Claim 13 (depends on 1) The circuit board of claim 1, wherein, in each of the one or more vias, the conductive material is configured to interconnect one of the plurality of conductive traces on the first surface layer with another one of the plurality of conductive traces on the second surface layer. ### Claim 14 A circuit board comprising: a liquid crystal polymer substrate defined by a thickness of 25 to 75 microns and including two opposing sides, wherein the first of the two opposing sides defines a first surface layer and wherein the second of the two opposing sides defines a second surface layer; one or more vias extending through the substrate and two opposing sides, wherein each of the one or more vias comprises at least one of conductive material or material plated to one or more walls of each of the one or more vias; a plurality of conductive traces positioned on at least one of the two opposing sides, wherein each of the one or more vias is configured to interconnect one of the plurality of conductive traces on the first surface layer with another one of the plurality of conductive traces on the second surface layer; a first adhesive positioned on the first surface layer, wherein the adhesive covers all of the first surface layer; a second adhesive positioned on the second surface layer, wherein the adhesive covers all of the second surface layer; a first cover layer positioned over the first adhesive on the first surface layer, wherein the first cover layer comprises a second liquid crystal polymer; and a second cover layer positioned over the second adhesive on the second surface layer, wherein the second cover layer comprises a third liquid crystal polymer. ### Claim 15 (depends on 14) The circuit board of claim 14 wherein each of the first liquid crystal polymer, the second liquid crystal polymer, and the third liquid crystal polymer is at least one of a partially crystalline aromatic polyesters, a polyester comprising monomer units derived from 4-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, a polyester comprising monomer units derived from 2,6-hydroxynaphthoic acid, terephthalic acid and acetaminophen, a polyester comprising monomer units derived from 4-hydroxybenzoic acid, terephthalic acid and 4,4′-biphenol, or a polyester comprising one or more aromatic dicarboxylic acids and alicyclic dicarboxylic acids, one or more aromatic diols, alicyclic diols and aliphatic diols, one or more aromatic hydroxy-carboxylic acids, one or more aromatic thiocarboxylic acids, one or more aromatic dithiols or aromatic dithiophenols, or one or more aromatic hydroxy hydroxylamines or aromatic diamines. ### Claim 16 (depends on 15) The circuit board of claim 15 wherein the first liquid crystal polymer, second liquid crystal polymer, and third liquid crystal polymer are a same liquid crystal polymer. ### Claim 17 (depends on 14) The circuit board of claim 14 wherein the first liquid crystal polymer has a thickness that is less than a thickness of the second liquid crystal polymer and less than a thickness of the third liquid crystal polymer and wherein the thickness of the second liquid crystal polymer is equal to the thickness of the third liquid crystal polymer. ### Claim 18 (depends on 14) The circuit board of claim 14 wherein the first liquid crystal polymer has a thickness that is less than a thickness of the second liquid crystal polymer and less than a thickness of the third liquid crystal polymer. ### Claim 19 (depends on 1) The circuit board of claim 1 wherein the first liquid crystal polymer has a thickness that is equal to a thickness of the second liquid crystal polymer and equal to a thickness of the third liquid crystal polymer. ### Claim 20 (depends on 14) The circuit board of claim 14 wherein the first liquid crystal polymer has a thickness that is more than a thickness of the second liquid crystal polymer and more than a thickness of the third liquid crystal polymer and wherein the thickness of the second liquid crystal polymer is equal to the thickness of the third liquid crystal polymer.