Fabrication of silicon carbide microchannels by thin diamond wheel grinding

Abstract

Silicon carbide (SiC) microchannels are attractive for their wide applications in microsensors, MOS devices, UV photodiodes, microcatalytic reactors, and microchannel heat exchangers in harsh environments. However, the machining of SiC microchannels poses many challenges because of the difficulty and cost involved in the material removal process due to the high hardness and brittleness of SiC ceramic. In the present study, we developed a thin diamond wheel grinding process to fabricate SiC microchannels in a conventional vertical milling machine. Microchannels with trapezoidal shapes were successfully processed in SiC substrates by thin diamond wheels. The formation, geometric dimensions, and surface quality of SiC microchannels were studied together with the analysis of material removal mechanism. The effects of grinding processing parameters, i.e., wheel speed, feed speed, grinding depth, and grinding tool parameters including grit size and thickness of diamond grinding wheel, on the geometric dimension and surface morphology were comprehensively explored. The top width of microchannels first increased and then decreased with the increase in wheel speed, whereas a reverse tendency was observed with increasing grinding depth, feed speed, and grit size. The surface roughness decreased continuously with increasing wheel speed, but it tended to increase with the increase in feed speed generally. The variations in geometric dimensions and surface roughness of SiC microchannels can be related to the crack or fracture propagations and material removal mechanism during the thin diamond wheel grinding process. Besides, the influential significance of the above processing and grinding tool parameters were also evaluated by analysis of variance (ANOVA).

High-Speed Dicing of SiC Wafers with 0.048 mm Diamond Blades via Rolling-Slitting

“…This could be because, in the case of an even higher spindle speed, the dicing distance of single abrasive grains decreased sharply, and the vertical grinding force tended to be smaller. Xie et al [21] observed a similar phenomenon when grinding silicon carbide microchannels, and they concluded that the grinding distance of single abrasive grains decreased at higher speeds, which reduced the vertical cutting force of a single abrasive, resulting in less material removal and a narrower kerf width. Nevertheless, when the spindle speed increased up to 28,000 rpm, the kerf width increased again, which is probably because the blade is vulnerable to instability during cutting with a high spindle speed; in short, the dicing blade body vibrates away from the blade-moving forward axis so that the width of the cutting slit broadened against the increase in amplitude.…”

“…Several researchers have attempted to dice silicon carbide [14][15][16][17][18][19][20][21][22][23][24][25], for example, using a diamond wire sawing [14], coating the blade with metallic glass [15,19], applying laser trimming to the blade or adjusting the binder materials [20,24]. Cvetkovic et al [18] demonstrated the viability of ultra-precision dicing and wire sawing to obtain a high surface quality and minimal edge chipping.…”

“…Yuan et al [20] performed high-speed micro-cutting of SiC using resin-bonded cutting blades and metal-bonded cutting blades, respectively, indicating that the performance of the metal-bonded cutting blades was inferior to that of the resin-bonded cutting blades. Xie et al [21] fabricated SiC microchannels with thin diamond grinding wheels and investigated the material removal mechanism of SiC microchannel grinding, and explored the effects of wheel speed, feed speed and grinding depth on SiC geometry and surface quality. Mu et al [22,23] designed a Ti-rich metal-based blade through a formula that exhibits good cutting quality when cutting silicon carbide; furthermore, they applied a sintered metal-bonded diamond blade for dicing single crystal SiC.…”