# US 8,569,632 B2 · Wiring board having through hole or non-through hole, and method for producing the same

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- Number: US 8,569,632 B2
- Document ID: US8569632B2
- Status: Granted
- Kind: B2
- Application number: 11/580,871
- Filed: 2006-10-16
- Published: 2008-04-24
- Granted: 2013-10-29
- Earliest claimed: 2006-10-16
- Assignees: Napra Co., Ltd.
- Applicants: Shigenobu Sekine; Yurina Sekine
- Inventors: Shigenobu Sekine; Yurina Sekine
- Web page: https://patentgrep.com/patent/US8569632B2

## CPC

- H05K 3/0094: {Filling or covering plated through-holes or blind plated vias, e.g. for masking or for mechanical reinforcement}
- H05K 3/4038: {Through-connections; Vertical interconnect access [VIA] connections (H05K3/403, H05K3/42 take precedence)}
- H05K 2201/0305: Solder used for other purposes than connections between PCB or components, e.g. for filling vias or for programmable patterns
- H05K 2203/0285: Using ultrasound, e.g. for cleaning, soldering or wet treatment
- H05K 2203/0425: Solder powder or solder coated metal powder
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

There is provided a circuit board including a substrate having a hole. Inside the hole, a metal wiring is formed. The wiring is made of a solder alloy having a melting point of 100 to 600° C., and the metal wiring includes a polycrystalline region of the solder alloy. The metal wiring of the present invention is superior in conductivity.

## Claims

### Claim 1

A circuit board, comprising;
a substrate having a hole having a diameter of 23 μm or less, and an aspect ratio of 5 or more; and
a wiring formed inside the hole, wherein the wiring is made of a lead free solder alloy having a melting point of 100 to 600° C., the solder alloy consisting of tin (Sn), bismuth (Bi), indium (In) and gallium (Ga),
wherein the wiring includes a polycrystalline region of the solder alloy, the wiring includes little voids,
wherein the tin (Sn) is included in the solder alloy at 30 to 80 wt %, and the bismuth (Bi) is included in the solder alloy at 20 to 58 wt %, and indium (In) is included in the solder alloy at 3 to 10 wt %, and gallium (Ga) is included in the solder alloy at 0.001 to 1 wt %.

### Claim 2 (depends on 1)

A circuit board according to claim 1, wherein the hole is a through hole or a non-through hole formed on the substrate.

### Claim 3 (depends on 1)

A circuit board according to claim 1, wherein the substrate is a wafer.

### Claim 4 (depends on 1)

A circuit board according to claim 1, wherein the wiring is formed by melting metal particles to fill the hole under a reduced pressure.

### Claim 5 (depends on 1)

A circuit board according to claim 1, wherein the solder alloy is a Sn based lead free alloy.

### Claim 6 (depends on 1)

A circuit board according to claim 1, wherein the diameter is 23 μm.

### Claim 7 (depends on 1)

A circuit board according to claim 1, wherein the tin (Sn) is included in the solder alloy at 30 to 85 wt %, and the bismuth (Bi) is included in the solder alloy at 15 to 60 wt %.

### Claim 8 (depends on 1)

A circuit board according to claim 1, wherein the tin (Sn) is included in the solder alloy at 30 to 85 wt %, and the bismuth (Bi) is included in the solder alloy at 15 to 60 wt %, and gallium (Ga) is included in the solder alloy at 0.001 to 3 wt %.