Browsing by Author "Yang, CR"

Now showing 1 - 3 of 3

High etching rate of GaN films by KrF excimer laser
(2001-05-22)
Chu, CF
;
Lee, CK
;
Yu, CC
;
Wang, YK
;
Tasi, JY
A study of laser processing of gallium nitride (GaN) material is reported. A pulsed KrF excimer laser at 248 nm with 20-nsec pulse width and 1 Hz repetition rate is used to etch the GaN film. We establish the material etching parameters under different environmental conditions. By changing the pulsed energy at constant pulse numbers, ablation of GaN surface was observed at threshold laser fluence about 0.3 J cm(-2). Laser etching increase with reducing environment pressure. Al 1.0 J cm (-2) laser fluence, the etching fate is about 35 nm per pulse at atmosphere pressure and increases to 60 nm per pulse at low pressure. The etched depth also increases with increasing laser fluence. The surface morphology of the etched surface was also investigated. (C) 2001 Elsevier Science B.V. All rights reserved.
Surface roughness measurement on microchannels by atomic force microscopy using a bent tapered fiber probe
(2000-10-01)
Chen, SH
;
Lin, HN
;
Yang, CR
;
電子物理學系
;
Department of Electrophysics
We demonstrate a high-resolution and nondestructive surface roughness measurement on microchannels by atomic force microscopy with the use of a bent tapered optical fiber probe. The probe was fabricated by a combination of laser heating-pulling and electric arc bending. Microchannels with a width of 41.5 mu m and a height of 31.9 mu m were fabricated on polycarbonate by excimer laser ablation and the resultant roughness was measured to be 4.8 nm. (C) 2000 American Institute of Physics. [S0034-6748(00)00210-0].
Ultrathick SU-8 mold formation and removal, and its application to the fabrication of LIGA-like micromotors with embedded roots
(2002-12-01)
Ho, CH
;
Chin, KP
;
Yang, CR
;
Wu, HM
;
Chen, SL
In this study, a novel method to completely remove crosslinked SU-8 without remnants of the resist or destroying the electroplated microstructures was utilized. The LIGA-like fabrication of a side-driven electrostatic micromotor was employed as an example to describe polymerized SU-8 resist removal. Using near-UV light, nickel components of the micromotor were electroplated 160 Pm in a 300 mum-thick SU-8 mold. A comparison of various approaches based on a commercial remover was performed during the mold removal process. Experimental results showed that components having 1 mum-deep substructures embedded in the substrate could provide stronger structures to withstand the internal stress due to the photoresist deformation. In addition, when the height of the electroplated structure was below two-thirds of the photoresist mold thickness, the net clamping force on the resist could be effectively reduced to make the removal of SU-8 with heated remover successfully. The rotor and the stator with embedded roots were released cleanly and thereby, assembled to form a high-aspect-ratio micromotor. The technique of SU-8 removal and LIGA-like process presented herein can be applied to the fabrication of other high-powered microactuators. (C) 2002 Elsevier Science B.V. All rights reserved.