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Preventing Overshoot in Liquid Cooled Circuit Device

IP.com Disclosure Number: IPCOM000084656D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Anolick, ES: AUTHOR [+2]

Abstract

As a liquid cooled circuit component produces more heat, the method of cooling changes from convection cooling to cooling by nucleate boiling. This transition to nucleate boiling tends to occur only with a significant increase in the temperature of the component above the maximum temperature for convection cooling. It has been found that nucleate boiling is enhanced and this temperature overshoot is prevented, if nucleate boiling sites are created to produce a flow of bubbles across the surface of the component.

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Preventing Overshoot in Liquid Cooled Circuit Device

As a liquid cooled circuit component produces more heat, the method of cooling changes from convection cooling to cooling by nucleate boiling. This transition to nucleate boiling tends to occur only with a significant increase in the temperature of the component above the maximum temperature for convection cooling. It has been found that nucleate boiling is enhanced and this temperature overshoot is prevented, if nucleate boiling sites are created to produce a flow of bubbles across the surface of the component.

The drawing shows a semiconductor chip 2 that is mounted on a support 3. The chip and the support are located in an enclosure that contains a cooling fluid. A resistance wire 4 is connected between two terminal points 5 on support 3. The wire 4 is heated to a temperature to produce nucleate boiling. Bubbles 6 rise from wire 4 and sweep across the surface of chip 2, where they cause nucleate boiling to occur at a lower temperature that prevents the temperature overshoot.

In a second arrangement for enhancing nucleate boiling cooling of a chip 2, holes on the back of the chip form nucleate boiling sites. The chip is masked in a pattern for holes of about 0.25 mil diameter with a separation between holes of about 0.3 mil. The holes are then etched to a depth of about 1 mil. These holes taper to a very small cross section, and each hole is a nucleation site for boiling.

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