# US 11,114,354 B2 · Printed wiring board, printed circuit board, prepreg

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- Number: US 11,114,354 B2
- Document ID: US11114354B2
- Status: Granted
- Kind: B2
- Application number: 16/324,199
- Filed: 2017-08-22
- Published: 2019-07-11
- Granted: 2021-09-07
- Earliest claimed: 2016-09-06
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Akira Ito; Eiichiro Saito; Kengo Yamanouti
- Web page: https://patentgrep.com/patent/US11114354B2

## CPC

- H10W 70/05: of insulating or insulated package substrates, or of interposers, or of redistribution layers (manufacture or treatment of leadframes H10W70/04)
- H10W 70/6875: {being on a metallic substrate, e.g. insulated metal substrates [IMS]}
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 3/4626: {characterised by the insulating layers or materials (H05K3/4688 takes precedence)}
- H05K 3/4655: {by using a laminate characterized by the insulating layer (general-purpose insulating materials H05K1/03, H05K3/4673)}
- H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40)
- H10W 70/685: comprising multiple insulating layers
- H10W 70/69: Insulating materials thereof
- H10W 70/692: Ceramics or glasses
- H10W 70/695: Organic materials
- H10W 90/401: {characterised by multiple insulating or insulated package substrates, interposers or RDLs}
- H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion}
- H05K 1/0366: {reinforced, e.g. by fibres, fabrics (H05K1/036 takes precedence)}
- H05K 1/0373: {containing additives, e.g. fillers (H05K1/036 takes precedence)}
- H05K 2201/068: wherein the coefficient of thermal expansion is important
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

A printed wiring board includes: an inner insulating layer including a conductive wire; a first outermost insulating layer disposed on a first surface of the inner insulating layer; and a second outermost insulating layer disposed on a second surface of the inner insulating layer. A bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from ¼ to ¾, inclusive, of a bending elastic modulus of the inner insulating layer. A glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

## Claims

### Claim 1

A printed wiring board comprising:
an inner insulating layer including a conductive wire;
a first outermost insulating layer disposed on a first surface of the inner insulating layer; and
a second outermost insulating layer disposed on a second surface of the inner insulating layer, wherein:
each of the first outermost insulating layer and the second outermost insulating layer is a cured product of a prepreg, the prepreg including a thermosetting resin composition and a base material impregnated with the thermosetting resin composition,
the thermosetting resin composition includes an elasticity lowering agent,
the elasticity lowering agent includes at least one selected from the group consisting of ethylene-acrylic rubber including carboxyl group, nitrile rubber including carboxyl group, core-shell type rubber, acrylic rubber powers, and silicone powders,
a bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from ¼ to ¾, inclusive, of a bending elastic modulus of the inner insulating layer, and
a glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

### Claim 2 (depends on 1)

The printed wiring board according to claim 1, wherein a coefficient of thermal expansion in a direction perpendicular to a thickness direction of the first outermost insulating layer and the second outermost insulating layer falls within ±30% of a coefficient of thermal expansion in a direction perpendicular to a thickness direction of the inner insulating layer.

### Claim 3 (depends on 1)

The printed wiring board according to claim 1, wherein:
the thermosetting resin composition further includes an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, and
with respect to 100 parts by mass of the epoxy resin, a mass ratio of the inorganic filler ranges from 50 parts by mass to 200 parts by mass, inclusive, and a mass ratio of the elasticity lowering agent ranges from 5 parts by mass to 70 parts by mass, inclusive.

### Claim 4 (depends on 1)

The printed wiring board according to claim 1, wherein:
the inner insulating layer includes an adhesive layer, a first inner layer member disposed on a first surface of the adhesive layer, and a second inner layer member disposed on a second surface of the adhesive layer,
the adhesive layer has insulating property,
the first inner layer member includes a first substrate and a first conductive wire disposed on a surface of the first substrate, and
the second inner layer member includes a second substrate and a second conductive wire disposed on a surface of the second substrate.

### Claim 5 (depends on 1)

A printed circuit board comprising:
the printed wiring board according to claim 1;
an outermost conductive wire disposed on an outside surface of at least one of the first outermost insulating layer and the second outermost insulating laver; and
an electronic component that is mounted so as to electrically connect to the outermost conductive wire.

### Claim 6

A prepreg used as a material for a printed wiring board, the printed wiring board including: an inner insulating layer including a conductive wire; a first outermost insulating layer disposed on a first surface of the inner insulating layer; and a second outermost insulating layer disposed on a second surface of the inner insulating layer, wherein:
a cured product of the prepreg constitutes each of the first outermost insulating layer and the second outermost insulating layer,
each of the first outermost insulating layer and the second outermost insulating layer is a cured product of a prepreg, the prepreg including a thermosetting resin composition and a base material impregnated with the thermosetting resin composition,
the thermosetting resin composition includes an elasticity lowering agent,
the elasticity lowering agent includes at least one selected from the group consisting of ethylene-acrylic rubber including carboxyl group, nitrile rubber including carboxyl group, core-shell type rubber, acrylic rubber powers, and silicone powders,
a bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from ¼ to ¾, inclusive, of a bending elastic modulus of the inner insulating layer, and
a glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

### Claim 7 (depends on 6)

The prepreg according to claim 6, wherein a coefficient of thermal expansion in a direction perpendicular to a thickness direction of the first outermost insulating layer and the second outermost insulating layer falls within ±30% of a coefficient of thermal expansion in a direction perpendicular to a thickness direction of the inner insulating layer.

### Claim 8 (depends on 6)

The prepreg according to claim 6, wherein:
the thermosetting resin composition further includes an epoxy resin, a curing agent, a curing accelerator, and an inorganic filler, and
with respect to 100 parts by mass of the epoxy resin, a mass ratio of the inorganic filler ranges from 50 parts by mass to 200 parts by mass, inclusive, and a mass ratio of the elasticity lowering agent ranges from 5 parts by mass to 70 parts by mass, inclusive.