Noncontact Selective Laser-Assisted Placement of Thinned Semiconductor Dice

New laser-induced forward transfer (LIFT) techniques promise to be a disruptive technology by enabling high-volume placement of ultrathin bare dice. Limitations of current die-attach techniques such as pick-and-place are presented and discussed which inspired the development of this new placement method. The thermo-mechanical selective laser-assisted die transfer (tmSLADT) process is introduced as an application of the unique blistering behavior of a dynamic releasing layer when irradiated by low-energy-focused UV laser pulses. The potential for tmSLADT to be the next generation LIFT technique is demonstrated by the touchless transfer of 65-mu m-thick silicon tiles between two substrates spaced 195 mu m apart. Additionally, the advantages of an enclosed blister actuator mechanism over previously studied ablative and thermal releasing techniques are discussed. Finally, experimental results indicate that this nonoptimized die transfer process compares with, and may exceed, the placement precision of current assembly techniques.