Pan Pacific Symposium Conference Proceedings


Author: Joel Sigmund
Company: SONIX INC.
Date Published: 2/2/1999   Conference: Pan Pacific Symposium

Abstract: Flip chip packages are becoming increasingly popular in the microelectronics industry to meet the need for product miniaturization and increased device input and output (i/o). Advanced products such as cell phones, computers, smart cards and pagers are getting smaller and becoming more powerful. Flip chips offer a smaller package outline with greater electrical interconnections necessary to meet the performance and demands of these advanced products. However, when a flip chip is assembled the electrical connections are no longer visible as they are with conventional perimeter leaded devices. Optical imaging methods are rendered obsolete in assuring the integrity of the electrical interconnects and bonded interfaces within the flip chip package since they are hidden by the chip itself. Without a method to assure the integrity of critical interfaces, control of the process and ultimately long term reliability of the device becomes questionable.

A need has arisen for a nondestructive tool which is capable of examining the integrity of flip chip interfaces. Acoustic microscopes now play an important role in the assembly of flip chip packages because they can look underneath the chip at the critical interfaces without cutting the package. Package defects such as underfill voiding, interconnect bump voiding, delamination, flux residue and alignment of bump to substrate metallization are detectable using a scanning acoustic microscope. This work summarizes the application of a digital scanning acoustic microscope on specific flip chip packaging problems.

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