Laser-induced　plasma　ablation　(LIPA)　using　a　248　nm　KrF　excimer　laser　was　investigated　for　microchannel　fabrication.　Examination　of　the　morphology　in　relation　to　ablation　performance　was　emphasized,　and　a　synthetic　LIPA　mechanism　model　was　proposed　based　on　the　results.　Backside　LIPA　with　a　metal　target　on　the　bottom　can　be　attributed　to　a　combination　of　two　phenomena:　laser-induced　plasma　vaporization　thermal　ablation　from　the　metal　target　below　and　enhanced　laser-glass　direct　interaction　from　the　plasma　residuum.　The　laser　absorption　enhancement　of　quartz　substrate　resulting　from　the　metal　residuum　was　validated　clearly　using　absorption　spectrum　measurements.　The　influence　of　laser　parameters　on　the　etching　quality　during　LIPA　was　also　analyzed　for　processing　optimization.　Finally,　fused　quartz　glass　microchannels　of　outstanding　surface　quality　and　dimension　uniformity　were　implemented.　The　channel　depth　was　28　mu　m,　and　the　bottom　surface　roughness　was　better　than　several　hundred　nanometers.