Acrylic-Type Resist Removal Using 532 nm Laser Pulses

Abstract

We have developed a resist removal process that uses a laser. Laser irradiation far below the ablation threshold was useful to remove a resist that was strongly adhered to the substrate. We used the second harmonics of Nd:YAG ͑Y 3 Al 5 O 12 ͒ laser pulses ͑532 nm͒ to irradiate the polyacrylic-type resist for manufacturing printed circuit boards. At appropriate laser fluence, the resist, which transmits the laser light 80% at 532 nm, was detached from the substrate while retaining its original shape. This technique is not based on laser ablation. Therefore, no damage occurred to the substrate. It was a dry process: it used neither water nor chemicals. Compared to conventional chemical processing, environmental pollution is prevented. Power consumption and running costs can be reduced.

Effect of heat-treatment temperature after polymer melt and blending ratio on the crystalline structure of PVDF in a PVDF/PMMA blend

“…21 We reported in our previous study that PVDF (form I) is obtained by heat treatment for 1 day at 120 1C with quenching after hot-press with PVDF/PMMA blend ratio 70:30 wt%. [22][23][24][25][26][27] In case of pure PVDF, PVDF became cloudy, although PVDF was quenched just after the hot-press, without heat treatment, and it formed crystal conformation of PVDF (form II). This result indicates rapid crystallization speed of PVDF.…”

“…This result indicates rapid crystallization speed of PVDF. 25 Therefore, we assume that the formation of PVDF (form I) with a PVDF/PMMA blend is strongly affected by the compatibility of PVDF and PMMA. Thus, the crystalline structure of PVDF can be controlled when the compatibility of PVDF and PMMA changes with the heat-treatment temperature at the instant PVDF and PMMA are blended.…”