UV laser microprocessing and post chemical etching on ultrathin Al_2O_3 ceramic substrate

摘要

In this study, an Nd:YVO_4 UV laser was used for microprocessing ultrathin (125 ìm) ceramic plates for use as a multi-layer microchip substrate. The effects of the UV laser microprocessing parameters, including laser power density, frequency, laser scanning speed, and pass delay on microprocessing accuracy and quality (kerf width and arithmetic average roughness R_a on the kerf sidewall) were investigated by means of a 4 x 4 orthogonal design. The key processing parameters were determined and optimized for small kerf width and minimal R_a of the kerf sidewall while retaining high production efficiency. Subsequent chemical etching of the laser processed areas was performed to reduce the kerf surface and kerf sidewall roughness by removing debris and the thin recast layer for the required size precision and post gilding treatment. The results showed that a clean surface and crack-free kerf sidewall with roughness R_a of 0.16 ìm could be achieved by laser microprocessing and chemical etching.