On the fabrication of minimizing bulges and reducing the feature dimensions of microchannels using novel CO2 laser micromachining

The shape of a cross-microchannel in polymer is a common pattern in MEMS and can be fabricated using traditional CO2 laser micromachining in air-cooling environment. However, it always suffers some problems during the fabrication process such as bulges, splashes, resolidification and the appearance of a heat affected zone around the rims of channels. In this paper, a novel method of Foil-Assisted CO2 LAser Micromachining (FACLAM) is proposed to fabricate the cross-microchannels in polymethylmethacrylate (PMMA) by significantly diminishing the bulges and the channel's feature sizes. The feature size of the cross-channel can be greatly reduced from 229.1 to 63.6 mu m with no clogging effect shown in the cross-junction position. The bulge height of the PMMA microchannel using FACLAM was reduced from the conventional size of 8.2 mu m to as small as 0.2 mu m. The ANSYS software was also used to analyze the temperature distribution of the PMMA microchannel during machining in air-cooling environment and with foil-mask assistance. The FACLAM approach can improve laser processing quality in air-cooling environment and has the merits of low-cost, easy fabrication and high surface quality.