| Research Abstract |
In this study, a fundamental investigation on short-pulse uv-laser micromachining of sapphire wafers was conducted for microfabrication of next-generation sensor-head devices. Examinations and results were as follows :
(i) Development of Fifth Harmonic Generation (HG) Pulse Nd : YAG System
With nonlinear crystals and temperature control systems, stable Forth-HG (wavelength: 266 nm) and Fifth-HG (213 nm) wave systems were assembled.
(ii) Development of PC-Controlled X-Y Stage Micromichining System
Controlling the uv-laser system and an X-Y stage with a personal computer, two-dimensional pattern machining became possible. With this system, hole-drilling, grooving, and surface removing characteristics of sapphire were investigated through a laser-microscope, SEM, and AFM. In addition, heat affecting zone (HAZ) depths were estimated after etching with hot phosphoric acid solution. As the results, holes of 10 μm in diameter and grooves with 20 μm-deep x 50 μm wide with limited HAZ were obtained.
(iii) Micromachining Characteristics of Q-sw Short-Pulse Fifth-HG Nd:YAG Pulses
Fine hole-drilling, fine grooving, and smooth surface removing characteristics with the uv-laser system were investigated. In each case, accurate surface removal was obtained. In these cases, bottom surfaces with average surface roughness of 200 nm could be achieved with homogenized beams.
(iv) Development of PC-Controlled X-Y Stage 3-D Micromachining System
Overlaying several two-dimensional patters, quasi-three-dimensional structures could be realized. With this system, 3-D structures, such as cubes or pyramids, could be machined, and each size of the structure were estimated by a laser-microscope. As the result, accuratesurface removing with the rate of 1〜15 μm/pulse for laser fluence of 60 J/cm^2 were obtained.
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