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Structures and Methods to Attach Ultra Thin Die to Printed Wiring Boards: 1)Using a Transparent Wafer and Heat Release Adhesive and 2) Using a Transparent Wafer and Photodegradable Adhesive

IP.com Disclosure Number: IPCOM000008481D
Original Publication Date: 2002-Jun-17
Included in the Prior Art Database: 2002-Jun-17
Document File: 3 page(s) / 57K

Publishing Venue

Motorola

Related People

Krishna Kalyanasundaram: AUTHOR [+4]

Abstract

Lower semiconductor package thickness and less weight are among the significant benefits of using ultra-thin die. The methodology used today to assemble circuits with ultra-thin die is time and labor-intensive as well as costly. A high-volume-compatible IC structure for a microelectronic device enabling the attachment of thin die to substrates is proposed that addresses the aforementioned issues.

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Structures and Methods to Attach Ultra Thin Die to Printed Wiring Boards: 1)Using a Transparent Wafer and Heat Release Adhesive and 2) Using a Transparent Wafer and Photodegradable Adhesive

 

By Krishna Kalyanasundaram, Daniel Gamota, Steve Schiefers and Andrew Skipor


SUMMARY

Lower semiconductor package thickness and less weight are among the significant benefits of using ultra-thin die. The methodology used today to assemble circuits with ultra-thin die is time and labor-intensive as well as costly. A high-volume-compatible IC structure for a microelectronic device enabling the attachment of thin die to substrates is proposed that addresses the aforementioned issues.

 

 

PROBLEM

Reduction in wafer thickness has increased the opportunities for miniaturization of portable electronics. Ultra-thin die provide the same functionality of standard thick die, while allowing for reduction of semiconductor package thickness and weight. The current methodology to handle ultra-thin die consists of attaching a thick non-transparent silicon wafer to the backside of the fragile ultra-thin die that acts as a planarizer and as a rigidizer. The ultra-thin die with the rigidizer is attached to the substrate using a standard pick-and-place machine (Fig. 1). The rigidizer/backing is released by immersing the circuit board assembly in a suitable solvent that degrades the adhesive.  The optimized process requires approximately 2hrs for the adhesive to be attacked by the solvent.  This methodology is slow and does not meet the cycle time demand that is typical of high-volume manufacturing. Further, this methodology requires additional equipment and manufacturing floor space. This, in turn, requires modification of a standard surface mo...