# US 5,702,807 A · Ceramic circuit board and manufacturing method thereof

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- Number: US 5,702,807 A
- Document ID: US5702807A
- Status: Granted
- Kind: A
- Application number: 08/734,315
- Filed: 1996-10-21
- Granted: 1997-12-30
- Earliest claimed: 1994-03-03
- Assignees: Shiko Electric Industries Co., Ltd.
- Inventors: Michio Horiuchi; Yoichi Harayama
- Web page: https://patentgrep.com/patent/US5702807A

## CPC

- H05K 3/4061: {for via connections in inorganic insulating substrates}
- H05K 1/092: {Dispersed materials, e.g. conductive pastes or inks}
- H10W 70/05: of insulating or insulated package substrates, or of interposers, or of redistribution layers (manufacture or treatment of leadframes H10W70/04)
- H10W 70/095: {of vias therein}
- H10W 70/098: {Applying pastes or inks, e.g. screen printing (H10W70/095 takes precedence)}
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 3/245: {Reinforcing conductive patterns made by printing techniques or by other techniques for applying conductive pastes, inks or powders; Reinforcing other conductive patterns by such techniques}
- H05K 3/4611: {by laminating two or more circuit boards (H05K3/4652 takes precedence)}
- H05K 3/4629: {laminating inorganic sheets comprising printed circuits, e.g. green ceramic sheets}
- H05K 2201/0317: Thin film conductor layer; Thin film passive component
- H05K 2203/025: Abrading, e.g. grinding or sand blasting
- H05K 2203/1383: Temporary protective insulating layer
- Y10S 428/901: Printed circuit
- Y10T 428/24917: including metal layer
- Y10T 428/24926: including ceramic, glass, porcelain or quartz layer
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A conductor circuit 12 made of aluminum is provided on a green sheet 10, the primary material of which is ceramic powder. The green sheets 10 are laminated and integrated into one body so that the conductor circuit 12 is not exposed onto the surface but is covered with the green sheet 10. The laminated body is fired at the firing temperature not lower than 660.degree. C. and a portion of the inner conductor circuit of the thus obtained sintered body is then exposed onto a surface of the substrate.

## Claims

### Claim 1

A fired ceramic circuit board structure comprising:
an insulating ceramic substrate; and
an aluminum wiring surrounded by said substrate,
said ceramic circuit board structure being characterized by having been fired at a temperature not lower than 660.degree. C. with said wiring surrounded by a ceramic greensheet precursor of said insulating ceramic substrate.

### Claim 2 (depends on 1)

The fired ceramic circuit board according to claim 1 wherein the ceramic substrate comprises at least one of alumina, mullite, cordierite and aluminum nitride.

### Claim 3 (depends on 2)

The fired ceramic circuit board according to claim 2, wherein the ceramic substrate further comprises glass phase containing silica.

### Claim 4 (depends on 1)

The fired ceramic circuit board according to claim 1, further comprising an exposed surface conductor circuit thereon formed by grinding said insulating ceramic substrate, after firing, to expose the surface conductor circuit.

### Claim 5

A ceramic circuit board structure comprising:
a solid, sintered body having an internal expanse and a plurality of external surfaces surrounding said internal expanse; and
an aluminum conductor element disposed entirely within said internal expanse and out of contact with said external surfaces.