Removal of SU-8 resists using hydrogen radicals generated by tungsten hot-wire catalyzer

We investigated removal of chemically amplified negative-tone i-line resist SU-8 using hydrogen radicals, which was generated by the catalytic decomposition of H2/N2 mixed gas (H2:N2 = 10:90vol.%) using tungsten hot-wire catalyzer. SU-8 with exposure dose from 7 (Dg100×0.5) to 280mJ/cm2(Dg100×20) were removed by hydrogen radicals without a residual layer. When the distance between the catalyzer and the substrate was 100mm, the catalyzer temperature was 2400°C, and the initial substrate temperature was 50°C, removal rate of SU-8 was 0.17m/min independent of exposure dose to the SU-8. Finally, we obtained high removal rate for SU-8 (exposure dose = 14mJ/cm2(Dg100)) of approximately 4m/min when the distance between the catalyzer and the substrate was 20mm, the catalyzer temperature was 2400°C, and the initial substrate temperature was 165°C.