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Promoting Nucleate Boiling of Semiconductor Devices in a Fluorocarbon

IP.com Disclosure Number: IPCOM000089064D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Alcorn, GE: AUTHOR [+2]

Abstract

In liquid-cooled semiconductor device packages a troublesome problem is the initiation of nucleate boiling on the device submerged in the coolant, typically a fluorocarbon coolant. Normally the initiation of boiling takes place at the irregularly cut edges of the semiconductor device, or in the confined space between the device and its carrier. The edge nucleation is purely random in nature and occasionally a device will be found to have no easily activated nucleate sites. In such a case the device temperature will rise to an unsatisfactory level during operation. The simple act of roughening the backside of the device, such as by sandblasting or etching, provides a marginal improvement over an untreated surface.

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Promoting Nucleate Boiling of Semiconductor Devices in a Fluorocarbon

In liquid-cooled semiconductor device packages a troublesome problem is the initiation of nucleate boiling on the device submerged in the coolant, typically a fluorocarbon coolant. Normally the initiation of boiling takes place at the irregularly cut edges of the semiconductor device, or in the confined space between the device and its carrier. The edge nucleation is purely random in nature and occasionally a device will be found to have no easily activated nucleate sites. In such a case the device temperature will rise to an unsatisfactory level during operation. The simple act of roughening the backside of the device, such as by sandblasting or etching, provides a marginal improvement over an untreated surface.

In this method the back surface of the device to be immersed in the coolant is subjected to a plasma etching or reactive ion etching operation in a suitable atmosphere, such as CF(4) 8% O(2). The process of roughening the surface can be varied by varying the power, the gas flow, the time, and the pressure of the gas. The process is compatible with present semiconductor device fabrication steps, and, therefore, may be integrated into a device fabrication line. It is a low cost, dry process that leaves no significant amount of particulates or chemical residues as by-products of the process.

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