# US 2021/0084751 A1 · Printed Wiring Board

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- Number: US 2021/0084751 A1
- Document ID: US20210084751A1
- Status: Published application
- Kind: A1
- Application number: 17/106,438
- Filed: 2020-11-30
- Published: 2021-03-18
- Earliest claimed: 2017-02-13
- Assignees: Tatsuta Electric Wire & Cable Co., Ltd.
- Applicants: Tatsuta Electric Wire & Cable Co., Ltd.
- Inventors: Yuusuke HARUNA; Takahiko KATSUKI; Tsuyoshi HASEGAWA; Hiroshi TAJIMA
- Web page: https://patentgrep.com/patent/US20210084751A1

## CPC

- H05K 1/0265: {characterized by the lay-out of or details of the printed conductors, e.g. reinforced conductors, redundant conductors, conductors having different cross-sections}
- H05K 1/0215: {Grounding of printed circuits by connection to external grounding means}
- H05K 1/0218: {by printed shielding conductors, ground planes or power plane (H05K1/0236 takes precedence)}
- H05K 9/00: Screening of apparatus or components against electric or magnetic fields (devices for absorbing radiation from an antenna H01Q17/00)
- H05K 3/323: {by applying an anisotropic conductive adhesive layer over an array of pads}
- H05K 2201/0776: Resistance and impedance
- H05K 2201/10371: Shields or metal cases
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Embodiments of a printed wiring board configured to inhibit increases in electrical resistance between a ground circuit and a reinforcement member are disclosed. The printed wiring board has a substrate film with a base film and a printed circuit, which printed circuit includes a ground circuit; an adhesive layer formed on the substrate film; and a conductive reinforcement member formed on the adhesive layer. The adhesive layer includes conductive particles. One or more layers of low-melting-point metal is or are provided between the adhesive layer and the substrate film; between the adhesive layer and the reinforcement member; and/or around the conductive particles.

## Claims

### Claim 1

A printed wiring board comprising:
a substrate film including a base film and a printed circuit including a ground circuit;
an adhesive layer formed on the substrate film; and
a conductive reinforcement member formed on the adhesive layer,
wherein the adhesive layer contains conductive particles and an adhesive resin,
a third low-melting-point metal layer is formed between the adhesive layer and the reinforcement member,
the ground circuit is electrically connected to the reinforcement member via the third low-melting-point metal layer.

### Claim 2 (depends on 1)

The printed wiring board according to claim 1,
wherein the third low-melting-point metal layer is formed from a metal having a melting point of 300° C. or lower.

### Claim 3 (depends on 1)

The printed wiring board according to claim 1,
wherein the third low-melting-point metal layer has a thickness of 0.1 to 50 μm.

### Claim 4 (depends on 1)

The printed wiring board according to claim 1,
wherein the third low-melting-point metal layer contains a flux.

### Claim 5 (depends on 1)

The printed wiring board according to claim 1,
wherein the conductive particles are at least one selected from the group consisting of first conductive particles each including a non-conductive core particle and a first low-melting-point metal layer formed on the non-conductive core, intrinsically conductive second conductive particles, and third conductive particles each including a conductive core particle and a first low-melting-point metal layer formed on the conductive core.

### Claim 6 (depends on 5)

The printed wiring board according to claim 5,
wherein the conductive particles are the first conductive particles and/or third conductive particles, and
the first low-melting-point metal layer is formed from a metal having a melting point of 300° C. or lower.

### Claim 7 (depends on 6)

The printed wiring board according to claim 6,
wherein the first low-melting-point metal layer has a thickness of 0.1 to 50 μm.

### Claim 8 (depends on 6)

The printed wiring board according to claim 6,
wherein the first low-melting-point metal layer contains a flux.

### Claim 9 (depends on 1)

The printed wiring board according to claim 1,
wherein a second low-melting-point metal layer is formed between the substrate film and the adhesive layer.

### Claim 10 (depends on 9)

The printed wiring board according to claim 9,
wherein the second low-melting-point metal layer is formed from a metal having a melting point of 300° C. or lower.

### Claim 11 (depends on 9)

The printed wiring board according to claim 9,
wherein the second low-melting-point metal layer has a thickness of 0.1 to 50 μm.

### Claim 12 (depends on 9)

The printed wiring board according to claim 9,
wherein the second low-melting-point metal layer contains a flux.

### Claim 13 (depends on 1)

The printed wiring board according to claim 1,
wherein the conductive particles have an average particle size of 1 to 200 μm.