Novel fusion welding technology of Si/glass using ultrashort laser pulses with high pulse repetition rates

Using ps laser pulses with high pulse repetition rates, novel fusion welding technique of Si/glass material combination has been developed, which can overcome the most problems encountered in existing anodic bonding, providing excellent joint strength and throughput. Our technique allows welding of Si/glass without pre- and post-heating at high spatial resolution down to 10μm at maximum joint strength of 80MPa, and is shown to provide much better performance than ns laser pulses based on the analysis of laser-matter interaction. No defects are found by cutting using standard blade dicer and accelerated life test (500 cycles: -40C∼85C) of the laser-welded joint, demonstrating the welding technique has excellent performance for applications to wafer-level packaging and hermetic sealing.