Study on the picosecond-pulsed laser micromachining for substrate-removed HgCdTe IRFPAs

The ps-laser micro-machining technology for substrate-removed HgCdTe IRFPAs is researched in this paper. By analysis the microstructure morphologies under different pulse energy, the ablation threshold is fitted. Based on the analysis of ablation threshold, we optimize the laser parameters and etch grooves on the HgCdTe chip which is substrate removed and thinned to 5μm. The FPAs experiment test results show that thermal effected area was about 10μm away from the grooves, and the laser has no effect on the ROIC under the HgCdTe chip. The results are important to verify the optimal strategy of ps-pulsed laser for robust operation of substrate-removed HgCdTe IRFPAs and for laser micromachining industrial applications.