Repetitive Operation of A Dense Plasma Soft X-ray Source for Micromachining

• Main Authors: Wong, D, Tan, T L, Patran, A, Hassan, S M, Zhang, T, Springham, S V, Lee, S, Rawat, R S, Lee, P
• Format: Conference Proceeding
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASPECT RATIO; KEV RANGE; MACHINING; NEON; PLASMA; PLASMA DIAGNOSTICS; PLASMA FOCUS; PLASMA PRODUCTION; SOFT X RADIATION; SWITCHES
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.2159359

The NX2 device, a low energy plasma focus, at the Nanyang Technological University in Singapore, was used as a soft X-ray (SXR) source for micromachining. The gas used was neon which produced SXRs in a narrow spectral range of 0.9 - 1.6 keV. The SXR yield from repetitive operation of the NX2 device was monitored and measured using a cost effective multi-channel SXR spectrometric system. The system consists of filtered BPX65 PIN diodes, with the associated electronics - an integrator, sample and peak holder, analogue switch, an A/D converter and a microcontroller. The system enables easy shot-to-shot statistical analysis under repetitive operation at adjustable preset trigger frequencies. A total of 4000 shots were fired at 0.5 Hz, using the same gas filling. The SXR production was at an average yield of 60 J/shot and a maximum single-shot yield of more than 100 J. The SXRs emitted by the NX2 device was used for contact micromachining, producing structures with an excellent aspect ratio of up to 20:1 on 25 mum SU-8 resist.