# US 10,371,612 B2 · Prepreg, metal-clad laminated plate, wiring board, and method for measuring thermal stress of wiring board material

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- Number: US 10,371,612 B2
- Document ID: US10371612B2
- Status: Granted
- Kind: B2
- Application number: 15/757,002
- Filed: 2016-09-09
- Published: 2018-09-27
- Granted: 2019-08-06
- Earliest claimed: 2015-09-25
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Keiko Kashihara; Hiroharu Inoue; Shingo Yoshioka; Takashi Hoshi
- Web page: https://patentgrep.com/patent/US10371612B2

## CPC

- G01N 3/18: Performing tests at high or low temperatures
- B32B 5/022: {Non-woven fabric}
- B32B 5/024: {Woven fabric}
- B32B 5/28: impregnated with or embedded in a plastic substance {(not used)}
- B32B 15/08: of synthetic resin
- B32B 15/12: of paper or cardboard
- B32B 15/14: next to a fibrous or filamentary layer
- B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)}
- B32B 37/1018: {using only vacuum}
- C08J 5/244: {using glass fibres}
- 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 1/0373: {containing additives, e.g. fillers (H05K1/036 takes precedence)}
- H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)}
- B32B 37/10: characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
- B32B 2038/0076: {Curing, vulcanising, cross-linking}
- B32B 2250/03: 3 layers
- B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
- B32B 2260/021: Fibrous or filamentary layer
- B32B 2260/028: Paper layer
- B32B 2260/046: Synthetic resin
- B32B 2262/0269: Aromatic polyamide fibres
- B32B 2262/0276: Polyester fibres
- B32B 2262/101: Glass fibres
- B32B 2264/102: Oxide or hydroxide
- B32B 2264/104: Oxysalt, e.g. carbonate, sulfate, phosphate or nitrate particles
- B32B 2307/308: Heat stability
- B32B 2307/54: Yield strength; Tensile strength
- B32B 2309/02: Temperature
- B32B 2309/105: Thickness
- B32B 2457/08: PCBs, i.e. printed circuit boards
- C08J 2363/00: Characterised by the use of epoxy resins; Derivatives of epoxy resins
- G01N 2203/0017: Tensile
- G01N 2203/0057: using stresses due to heating, e.g. conductive heating, radiative heating
- H05K 1/038: {Textiles (used as reinforcing materials for organic insulating substrates H05K1/0366)}
- H05K 2201/0209: Inorganic, non-metallic particles
- H05K 2201/068: wherein the coefficient of thermal expansion is important
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

A prepreg includes a resin layer constituted by a half-cured product of a thermosetting resin composition, and a fibrous substrate provided in the resin layer. A prepreg test piece that is a cured product obtained by heat curing the thermosetting resin composition has a maximum value of 400 kPa or less for thermal shrinkage stress measured by a predetermined thermal stress test.

## Claims

### Claim 1

A prepreg comprising
a resin layer constituted by a half-cured product of a thermosetting resin composition, and
a fibrous substrate provided in the resin layer,
wherein a maximum value of thermal shrinkage stress of 400 kPa or less is measured during a thermal shrinkage test of a test piece of the prepreg,
the test piece being a cured product obtained by heat curing the thermosetting resin composition and having a thickness of 0.1 mm,
the thermal shrinkage stress being obtained by holding the prepreg test piece at both ends by jigs and measuring, as the thermal shrinkage stress, tensile stress between the jigs, and the tensile stress being measured during a period in which a temperature of the prepreg test piece is lowered from 260° C. to normal temperature after the prepreg test piece is heated to a temperature of 260° C. while a distance between the jigs is changed in a range from 0.01 ppm/° C. to 5 ppm/° C., inclusive, by allowing the jigs to come closer to each other.

### Claim 2

A prepreg comprising
a resin layer constituted by a half-cured product of a thermosetting resin composition, and
a fibrous substrate provided in the resin layer,
wherein a maximum value of thermal expansion stress of 100 kPa or less is measured during a thermal shrinkage test of a test piece of the prepreg,
the test piece being a cured product obtained by heat curing the thermosetting resin composition and having a thickness of 0.1 mm,
the thermal expansion stress being obtained by holding the prepreg test piece at both ends by jigs and measuring, as the thermal expansion stress, tensile stress between the jigs, and the tensile stress being measured during a period in which a temperature of the prepreg test piece is raised from normal temperature to 260° C. while a distance between the jigs is changed in a range from 0.01 ppm/° C. to 5 ppm/° C., inclusive, by allowing the jigs to separate from each other.

### Claim 3 (depends on 1)

The prepreg according to claim 1,
wherein a maximum value of thermal expansion stress of 100 kPa or less is measured during a thermal shrinkage test of a test piece of the prepreg,
the test piece being a cured product obtained by heat curing the thermosetting resin composition and having a thickness of 0.1 mm,
the thermal expansion stress being obtained by holding the prepreg test piece at both ends by jigs and measuring, as the thermal expansion stress, tensile stress between the jigs, and the tensile stress being measured during a period in which a temperature of the prepreg test piece is raised from normal temperature to 260° C. while a distance between the jigs is changed in a range from 0.01 ppm/° C. to 5 ppm/° C., inclusive, by allowing the jigs to separate from each other.

### Claim 4 (depends on 1)

The prepreg according to claim 1, wherein the thermosetting resin composition contains at least one resin selected from the group consisting of an epoxy resin, a polyimide resin, a polyphenylene oxide (PPO) resin, a radically polymerizable resin, and modified resins thereof.

### Claim 5 (depends on 1)

The prepreg according to claim 1, wherein the thermosetting resin composition contains at least two resins selected from the group consisting of an epoxy resin, a polyimide resin, a polyphenylene oxide (PPO) resin, a radically polymerizable resin, and modified resins thereof.

### Claim 6 (depends on 1)

The prepreg according to claim 1, wherein the fibrous substrate is woven fabric or nonwoven fabric.

### Claim 7 (depends on 1)

The prepreg according to claim 1, wherein the thermosetting resin composition further contains an inorganic filler.

### Claim 8 (depends on 1)

A metal-clad laminate comprising a cured product of the prepreg according to claim 1, and metal foil provided on at least one of upper surface of the cured product of the prepreg and lower surface of the cured product of the prepreg.

### Claim 9 (depends on 1)

A wiring board comprising a cured product of the prepreg according to claim 1, and a conductor pattern provided as a circuit on a surface of the cured product of the prepreg.

### Claim 10

A method for measuring thermal stress of a wiring board material, the method comprising:
holding both ends of a test piece constituted by the wiring board material by jigs, respectively, and
measuring tensile stress between the jigs which is defined as thermal shrinkage stress, the tensile stress being measured during a period in which a temperature of the test piece is lowered from 260° C. to normal temperature after the test piece is heated to a temperature of 260° C. while a distance between the jigs is changed in a range from 0.01 ppm/° C. to 5 ppm/° C., inclusive, by allowing the jigs to come closer to each other.

### Claim 11

A method for measuring thermal stress of a wiring board material, the method comprising:
holding both ends of a test piece constituted by the wiring board material by jigs, respectively, and
measuring tensile stress between the jigs which is defined as thermal expansion stress, the tensile stress being measured during a period in which a temperature of the test piece is raised from normal temperature to 260° C. while a distance between the jigs is changed in a range from 0.01 ppm/° C. to 5 ppm/° C., inclusive, by allowing the jigs to separate from each other.