# US 8,465,719 B2 · Silicon carbide substrate, semiconductor device, wiring substrate, and silicon carbide manufacturing method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,465,719 B2
- Document ID: US8465719B2
- Status: Granted
- Kind: B2
- Application number: 12/425,247
- Filed: 2009-04-16
- Published: 2009-10-22
- Granted: 2013-06-18
- Earliest claimed: 2008-04-18
- Assignees: National University Corporation Tohoku University; Mitsui Engineering & Shipbuilding Co., Ltd.
- Applicants: Tadahiro Ohmi; Akinobu Teramoto; Sumio Sano; Fusao Fujita
- Inventors: Tadahiro Ohmi; Akinobu Teramoto; Sumio Sano; Fusao Fujita
- Web page: https://patentgrep.com/patent/US8465719B2

## CPC

- C23C 16/325: {Silicon carbide}
- C23C 16/01: on temporary substrates, e.g. substrates subsequently removed by etching
- C23C 16/56: After-treatment
- H05K 3/0011: {Working of insulating substrates or insulating layers}
- H10W 70/66: Conductive materials thereof
- H05K 1/024: {Dielectric details, e.g. changing the dielectric material around a transmission line}
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 2203/1105: Heating or thermal processing not related to soldering, firing, curing or laminating, e.g. for shaping the substrate or during finish plating
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- 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

## Abstract

A silicon carbide substrate has a high-frequency loss equal to or less than 2.0 dB/mm at 20 GHz is effective to mount and operate electronic components. The silicon carbide substrate is heated at 2000° C. or more to be reduced to the high-frequency loss equal to 2.0 dB/mm or less at 20 GHz. Moreover, manufacturing the silicon carbide substrate by CVD without flowing nitrogen into a heater enables the high-frequency loss to be reduced to 2.0 dB/mm or less.

## Claims

### Claim 1

A silicon carbide substrate manufacturing method comprising:
preparing a preliminary silicon carbide substrate that is formed by chemical vapor deposition (CVD) and that has an RF loss higher than 2 dB/mm at a frequency of 20 GHz, when the RF loss is represented by an operation transmission matrix (S21) of signal passage characteristics; and
heating the preliminary CVDed silicon carbide substrate in a noble gas atmosphere at a temperature between 2000° C. and 2300° C. to reduce the RF loss equal to or less than 2 dB/mm; and
wherein:
the preliminary CVDed silicon substrate is heated under a nitrogen atmosphere to a temperature lower than 2000° C. and then heated to a temperature between 2000° C. and 2300° C. under the noble gas atmosphere.

### Claim 2 (depends on 1)

The silicon carbide substrate manufacturing method claimed in claim 1, wherein the CVD is performed by the use of a CVD apparatus having a heater unit and the preliminary CVDed silicon carbide substrate is formed by the CVD in a state of flowing nitrogen into the heater unit or without flowing nitrogen into the heater unit.

### Claim 3 (depends on 1)

The silicon carbide substrate manufacturing method claimed in claim 1, wherein the preliminary CVDed silicon carbide substrate is heated to a temperature of 800° C. which is lower than 2000° C. and then heated to the temperature between 2000° C. and 2300° C.