Surface and subsurface characterisation in micro-milling of monocrystalline silicon.

Huo, Dehong; Lin, Chao; Choong, Zi Jie; Pancholi, Ketan; Degenaar, Patrick

Abstract

This paper presents an experimental investigation on surface and subsurface characterisation of micro-machined single-crystal silicon with (100) orientation. Full immersion slot milling was conducted using solid cubic boron nitride (CBN) and diamond-coated fine grain tungsten carbide micro-end mills with a uniform tool diameter of 0.5 mm. The micro-machining experiments were carried out on an ultra-precision micro-machining centre. Formal design of experiments (DoE) techniques were applied to design and analysis of the machining process. Surface roughness, edge chipping formation and subsurface residual stress under varying machining conditions were characterised using white light interferometry, SEM and Raman microspectroscopy. Tens of nanometre-level surface roughness can be achieved under the certain machining conditions, and influences of variation of cutting parameters including cutting speeds, feedrate and axial depth of cut on surface roughness were analysed using analysis of variance (ANOVA) method. Raman microspectroscopy studies show that compressive subsurface residual stress and amorphous phase transformation were observed on most of the micro-machined subsurface, which provides evidence of ductile mode cutting. Surface and subsurface characterisation studies show that the primary material removal mode is ductile or partial ductile using lower feedrate for both tools, and diamond-coated tools can produce better surface quality. Silicon brain implants were fabricated with good dimensional accuracy and edge quality using the optimised machining conditions, which demonstrated that micro-milling is an effective process for fabrication of silicon components at a few tens to a few hundreds of micron scale.

Citation

HUO, D., LIN, C., CHOONG, Z.J., PANCHOLI, K. and DEGENAAR, P. 2015. Surface and subsurface characterisation in micro-milling of monocrystalline silicon. International journal of advanced manufacturing technology [online], 81(5-8), pages 1319-1331. Available from: https://doi.org/10.1007/s00170-015-7308-7

• Journal Article Type: Article
• Acceptance Date: May 11, 2015
• Online Publication Date: May 21, 2015
• Publication Date: Nov 1, 2015
• Deposit Date: Jan 5, 2017
• Publicly Available Date: Jan 5, 2017
• Journal: International journal of advanced manufacturing technology
• Print ISSN: 0268-3768
• Electronic ISSN: 1433-3015
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 81
• Issue: 5-8
• Pages: 1319-1331
• DOI: https://doi.org/10.1007/s00170-015-7308-7
• Keywords: Micromilling; Monocrystalline silicon; Ductile mode cutting; Subsurface residual stress; Machining induced edge chipping; Diamond tool
• Public URL: http://hdl.handle.net/10059/2070