# US 5,349,499 A · Immersion cooling coolant and electronic device using this coolant

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- Number: US 5,349,499 A
- Document ID: US5349499A
- Status: Granted
- Kind: A
- Application number: 08/053,452
- Filed: 1993-04-28
- Granted: 1994-09-20
- Earliest claimed: 1990-05-11
- Assignees: Fujitsu Limited
- Inventors: Mitsutaka Yamada; Kishio Yokouchi; Nobuo Kamehara; Koichi Niwa
- Web page: https://patentgrep.com/patent/US5349499A

## CPC

- H10W 40/73: for cooling by change of state
- H05K 7/203: {by immersion}
- 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 coolant for cooling a semiconductor element by direct immersion, cooling, which has an improved cooling capability, is disclosed. The coolant comprises a low boiling point fluorocarbon having a boiling point of 30.degree. C. to 100.degree. C. and a high boiling point fluorocarbon having a boiling point higher than that of the low boiling point fluorocarbon by at least 100.degree. C.; an amount of the high boiling point fluorocarbon being less than 20% by volume, based on the volume of the low boiling point fluorocarbon.

## Claims

### Claim 1

A boiling cooling-type electronic device for using at a temperature in a range of room temperature to 80.degree. C., comprising an electronic element having a heat generating portion immersed in a liquid coolant, the liquid coolant comprising a low boiling point fluorocarbon having a boiling point of 30.degree. C. to 100.degree. C. and a high boiling point fluorocarbon having a boiling point of 150.degree. C. to 260.degree. C. and higher than that of the low boiling point fluorocarbon by at least 100.degree. C., an amount of the high boiling point fluorocarbon being from 1.5% by volume to 20% by volume, based on the volume of the low boiling point fluorocarbon.

### Claim 2 (depends on 1)

A device according to claim 1, wherein said low boiling point fluorocarbon has a boiling point of 30.degree. to 56.degree. C. and said high boiling point fluorocarbon has a boiling point of 215.degree. to 253.degree. C.

### Claim 3 (depends on 1)

A device according to claim 1, wherein said high boiling point fluorocarbon is contained in an amount of less than 9% by volume, based on the volume of the low boiling point fluorocarbon.

### Claim 4 (depends on 1)

A device according to claim 1, wherein said high boiling point fluorocarbon is selected from the group consisting of tris(p-fluoropentyl)amine, p-fluoroanthracene and tris(p-fluorophenanthrene).

### Claim 5 (depends on 1)

A device according to claim 1, wherein said high boiling point fluorocarbon is tris(p-fluoropentyl)amine.

### Claim 6 (depends on 1)

A device according to claim 1, wherein said high boiling point fluorocarbon is p-fluoroanthracene.

### Claim 7 (depends on 1)

A device according to claim 1, wherein the high boiling point fluorocarbon is tris(p-fluorophenanthrene).

### Claim 8 (depends on 1)

A device according to claim 1, wherein said low boiling point fluorocarbon is selected from the group consisting of C.sub.5 F.sub.12 and C.sub.6 F.sub.14.

### Claim 9 (depends on 1)

A device according to claim 1, wherein said low and high boiling point fluorocarbons are selected from compounds represented by the formula C.sub.n F.sub.2n+2 and C.sub.n F.sub.2n, where n is a positive integer.