Mask opening

Microabrasion using compressed air is a modification based on sandblasting, the micropowder blasting. This process enables all types of glass, ceramics and semiconductor materials, irrespective of their chemical composition and crystal structure, to be inexpensively processed down to the micrometer scale. The micropowder blasting is a masked procedure and works quasi-parallel on the whole substrate. A powder jet drives systematically over the substrate. Material is removed at the mask openings (see Figure 2.17). 

Figure 13.27 Diffraction pattern of a coherently illuminated mask opening at near (Fresnel) and far (Fraunhofer) distances. (Reprinted with permission from Taylor Francis Group LLC. )...

Lack of proper clearance on solder mask openings... 

The masking material used is Si02 or Si3N4 (see Table 3.3). Rectangular mask openings oriented in the (110) direction lead to the creation of rectangular troughs... 

It is possible to control the depth of geometrical structures in a glass sheet using a fine pattern (substructure) of mask openings which allows fabrication of three-dimensional structures (without undercut). 

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