We present a low-temperature post-processing module, utilizing polyimide as a sacrificial layer and novel materials such as PECVD SiC and metals (sputtered aluminium and titanium) as structural layers. The use of spin-on polyimide allows an all-dry final release step overcoming stiction problems often encountered in wet sacrificial etching processes. The spinning and curing procedure has been tailored to the specific needs of the IC-compatible post-process module. For the patterning of the polyimide, thin films of aluminium, PECVD silicon oxide or silicon carbide are employed as a mask layer. Anisotropic etching of the mask film and of the polyimide layer is accomplished by RIE. After patterning the structural layer, sacrificial etching of the polyimide is done using an isotropic dry etch process in high-density oxygen plasma. An underetch rate of 4 μm min−1 is achieved. Compatibility with different structural materials is tested and test structures are designed and realized in a fully post-processing surface micromachining module.

In this work, we present a technology for fabrication of nanochannels created in glass with which bio-analysis can be performed in combination with fluorescence microscopy. The technology is based on a glass-to-glass anodic bonding process. In the bonding process, an intermediate layer (thin insulating film) is deposited on one of the two glass wafers. The channel is then defined, with one or two photo-patterning steps, in the intermediate layer. In our approach, a 33 nm thick amorphous silicon layer deposited by low-pressure chemical vapor deposition (LPCVD) was used as an intermediate layer. The depth of the channel is defined during the etching of this layer.

The fabrication and characteristics of CMOS compatible absolute pressure sensors for harsh environments are presented in this paper. The sensor which was fabricated using post-processing surface micromachining consists of 100 circular membranes with a total capacity of 14 pF. PECVD SiC was used due to its good mechanical properties, but since SiC has high resistivity, aluminium layers were used for electrodes. The stiction problems were avoided by using polyimide PI2610 as a sacrificial layer. The pressure sensors were fabricated and the change of capacitance over full pressure range, 5 bar, was 3.4 pF.

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