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Ultrasonic Bonds with Delayed Thermal Pulse

IP.com Disclosure Number: IPCOM000073355D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Joshi, KC: AUTHOR

Abstract

The success of ultrasonic bonding depends on close material compatibility. Since close control in surface and mechanical characteristics is difficult, a simple way of attaining consistent bonds is desirable.

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Ultrasonic Bonds with Delayed Thermal Pulse

The success of ultrasonic bonding depends on close material compatibility. Since close control in surface and mechanical characteristics is difficult, a simple way of attaining consistent bonds is desirable.

This technique leads to less scatter in bond data and widens the range of material properties suitable for ultrasonic bonding. Based on a softening theory of ultrasonic bonding, if during the last 25% to 30% of the bonding cycle a thermal pulse is superimposed, then the localized softening enhances the bonds which also become more consistent. The temperature necessary for gold is in a range of from 200 degrees to 300 degrees C. Once the clean surfaces have been brought into intimate contact, a short pulse of heat will accelerate the softening and enhance the bond formation.

This technique has superior effects on the bonding of harder materials which also have high recrystallization temperatures. However, in order to prevent undue oxidation it may be necessary to use an inert atmosphere during the bonding operation.

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