Here is the abstract you requested from the IMAPS_2009 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Micron Level Placement Accuracy for Wafer Scale Packaging of P-Side Down Lasers in Optoelectronic Products|
|Keywords: Wafer Scale Package, P-Side Down Laser, Eutectic Attach|
|Applications requiring ultra high placement accuracies of 1um to 3um are resurfacing in several optoelectronic applications such as Arrayed Laser Print Heads, P-Side-Down Laser Applications, and multi-channel optical communication products. An overview of the technology and the placement accuracy and attachment method is presented for wafer level P-Side down AuSn Laser attachment. This paper will cover the differences in measurement, material, and process controls that are required to successfully achieve high placement accuracies of 3um at the wafer level for chip to wafer (C2W) or Die to Wafer (D2W) eutectic attachment. P-Side down laser attachment using eutectic solder is a mature process and has been used extensively for long haul and metro distance laser transmit modules. The P-Side laser attach to heat spreader has traditionally been done using singulated heat spreaders with a pulsed heat in-situ reflow stage. Continued work in P-Side-Down laser attachment has expanded the technology to Wafer Scale – P-Side Laser Die to Wafer attachment. This technology shifts away from singulated submounts to bonding directly on wafer. Design considerations for component heat flow, power limits, and reliability are significantly affected by specific geometry, materials, and interconnect process. This case study will focus on the pick and place and attachment capability. Substrate time at temperature and its effect on solder reflow and solder aging are explored. Measurement methods for P-Side down laser attachment provide some challenges during process development and will be covered. A review of guidelines and actual results will be shared in this paper.|
|Daniel D. Evans, Jr., Senior Scientist / Applications Manager