Browse Prior Art Database

Heat Transfer From Silicon Chips and Wafers

IP.com Disclosure Number: IPCOM000083354D
Original Publication Date: 1975-May-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Noth, RW: AUTHOR

Abstract

Roughing the back surface 10 of a silicon chip or wafer 12, shown in Figs. 1 and 2, with a laser beam improves heat transfer between a chip or wafer 12 which may be immersed in a liquid coolant, not shown.

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Heat Transfer From Silicon Chips and Wafers

Roughing the back surface 10 of a silicon chip or wafer 12, shown in Figs. 1 and 2, with a laser beam improves heat transfer between a chip or wafer 12 which may be immersed in a liquid coolant, not shown.

Back surface 12 may be cut by any suitable laser beam to a depth of approximately 5 or 6 mils on an 8 mil pitch, to form a first set of lines or grooves 14. A similar second set of lines or grooves 16 is arranged substantially orthogonally with respect to the first set 14. The laser beam converts the silicon of the chip or wafer 12 into a silicon dioxide mass 18, indicated in Fig. 2, which is a sectional view of a portion of the wafer 12 shown in Fig. 1.

This mass 18 located within grooves 14 and 16 is permeable to the liquid coolant.

It is known that the difference in temperature between the chip or wafer 12 and the liquid coolant is a function of the heat transfer coefficient h, with higher values of h producing a smaller difference in temperature. The laser-cut back surface 10 significantly increases the heat transfer coefficient h, by providing not only an increase in surface area of the silicon at the back surface 10 but also by providing the permeable silicon dioxide mass 18, which creates additional surface area and boiling sites for earlier nucleate boiling of the liquid coolant.

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