# US 2021/0243893 A1 · Printed circuit board and method of manufacturing printed circuit board

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- Number: US 2021/0243893 A1
- Document ID: US20210243893A1
- Status: Published application
- Kind: A1
- Application number: 17/166,110
- Filed: 2021-02-03
- Published: 2021-08-05
- Earliest claimed: 2020-02-04
- Assignees: Yazaki Corporation
- Applicants: Yazaki Corporation
- Inventors: Yukito AOYAMA; Shota SATO; Rie TONE; Kosuke TASHIRO; Toshio YAMAGUCHI
- Web page: https://patentgrep.com/patent/US20210243893A1

## CPC

- H05K 1/095: {for polymer thick films, i.e. having a permanent organic polymeric binder}
- C08L 1/02: Cellulose; Modified cellulose
- C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins
- H05K 1/0296: {Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 (H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18)}
- H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions}
- H05K 3/1283: {After-treatment of the printed patterns, e.g. sintering or curing methods}
- H05K 1/028: {Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence)}
- H05K 1/032: {consisting of one material}
- H05K 1/097: {Inks comprising nanoparticles and specially adapted for being sintered at low temperature (H05K1/095 takes precedence)}
- H05K 1/181: associated with surface mounted components
- H05K 3/1216: {by screen printing or stencil printing}
- H05K 2201/0215: Metallic fillers
- H05K 2201/0257: Nanoparticles
- H05K 2201/0266: Size distribution
- H05K 2201/0272: Mixed conductive particles, i.e. using different conductive particles, e.g. differing in shape
- H05K 2201/10015: Non-printed capacitor
- H05K 2201/10022: Non-printed resistor
- H05K 2201/10151: Sensor
- H05K 2201/10166: Transistor
- H05K 2201/10174: Diode
- H05K 2203/1572: Processing both sides of a PCB by the same process; Providing a similar arrangement of components on both sides; Making interlayer connections from two sides
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

A printed circuit board includes a substrate and wiring provided on a surface of the substrate and including a cured conductive paste. The conductive paste contains metal nanoparticles having an average particle diameter of 30 nm or more and 600 nm or less, metal particles having an average particle diameter larger than that of the metal nanoparticles, a thermosetting resin having an oxirane ring in a molecule, a curing agent, and a cellulose resin. The wiring has a width of 0.3 mm or more and 6 mm or less, a thickness of 10 μm or more and 40 μm or less, and a resistance value of 500 mΩ/m or more and 5000 mΩ/m or less, and a welding strength of the electronic component to the substrate is 30 N or more.

## Claims

### Claim 1

A printed circuit board comprising:
a substrate;
wiring provided on a surface of the substrate and including a cured conductive paste containing metal nanoparticles having an average particle diameter of 30 nm or more and 600 nm or less, metal particles having an average particle diameter larger than that of the metal nanoparticles, a thermosetting resin having an oxirane ring in a molecule, a curing agent, and a cellulose resin; and
an electronic component connected to the substrate via the wiring,
wherein the wiring has a width of 0.3 mm or more and 6 mm or less, a thickness of 10 μm or more and 40 μm or less, and a resistance value of 500 mΩ/m or more and 5000 mΩ/m or less, and
a welding strength of the electronic component to the substrate is 30 N or more.

### Claim 2 (depends on 1)

The printed circuit board according to claim 1, wherein the thermosetting resin having the oxirane ring in the molecule is at least one selected from the group consisting of a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a novolac type epoxy resin, a glycidylamine type epoxy resin, and an aliphatic type epoxy resin.

### Claim 3 (depends on 1)

The printed circuit board according to claim 1, wherein the average particle diameter of the metal particles is 1 μm or more and 5 μm or less.

### Claim 4 (depends on 1)

The printed circuit board according to claim 1, wherein the wiring is provided on both surfaces of the substrate.

### Claim 5 (depends on 1)

The printed circuit board according to claim 1, wherein the substrate has a curved surface, and the wiring is provided on the curved surface.

### Claim 6

A method of manufacturing a printed circuit board, comprising:
applying a conductive paste to a surface of a substrate; and
curing the applied conductive paste to form wiring,
wherein the conductive paste contains metal nanoparticles having an average particle diameter of 30 nm or more and 600 nm or less, metal particles having an average particle diameter larger than that of the metal nanoparticles, a thermosetting resin having an oxirane ring in a molecule, a curing agent, and a cellulose resin,
the wiring has a width of 0.3 mm or more and 6 mm or less, a thickness of 10 μm or more and 40 μm or less, and a resistance value of 500 mΩ/m or more and 5000 mΩ/m or less, and
a welding strength of the electronic component to the substrate is 30 N or more.