Thermo-Mechanical Selective Laser Assisted Die Transfer

Abstract

Laser Induced Forward Transfer (LIFT) techniques show promise as a disruptive technology which will enable the placement of components smaller than what conventional pick-and-place techniques are capable of today. Limitations of current die-attach techniques are presented and discussed and present the opportunity for a new placement method. This study introduces the Thermo-Mechanical Selective Laser Assisted Die Transfer (tmSLADT) process and is an application of the unique blistering behavior of a dynamic releasing layer when irradiated by low energy focused UV laser pulses. The potential of tmSLADT as the next generation LIFT technique is demonstrated by the "touchless" transfer of 65 μm thick silicon tiles between two substrates spaced 195 μm apart. Additionally, the advantages of an enclosed blister-actuator mechanism over previously studied ablative and thermal releasing techniques are discussed. Finally, experimental results studying transfer precision indicate this non optimized die transfer process compares with, and may exceed, the placement precision of current assembly techniques.