Implementing a Tab Tape-based Known Good Die Method

Abstract

The success of nearly every multichip electronic system depends on the availability of functional, reliable chips. As chip counts in a multichip system increase, this dependency is critical. In most cases, "known good" die (KGD) are not readily available in an unpackaged form. This was a prime consideration in MCC's. Flip Chip Development Project. As part of this project, MCC was chartered with developing a method for high speed test and dynamic burn-in of single, bare IC chips. The method developed can be implemented by bare die users using "off-the-shelf" technology. It can also be implemented by bare chip suppliers without modification to the existing fabrication processes. The heart of this process is a TAB tape-based carrier. TAB tape is used to contact the chip bond pads (without actual metallurgical bonding) at about 10 grams per lead contact force. The chip is clamped to the TAB leads, and held in place so that the tape site (in its JEDEC-standard slide carrier) can be transported, tested, and burned-in just like TAB chip-on-tape. Upon test completion, the chip is removed, and is ready for wire bonding, flip chip attach, etc. The carrier has been characterized with aluminum, gold, and solder-bumped chip bond pads, and is compatible with these pad metallizations. Four re-uses of the carrier through 168 hours/150"C of burn-in have been demonstrated. In this paper, the results of MCC's initial prototype testing are discussed. Data includes contact resistance vs. pressure, chip metallurgy, and time. The cost of this approach is presented for a wide range of production volumes. In addition, preliminary results from beta-site testing (by a bare chip supplier) of this method are presented.