Deposition of AZ5214-E Layers on Non-planar Substrates with a "Draping" Technique

A draping technique was tested to deposit AZ5214-E resist on non-planar (100)-oriented III-V substrates that contained various three-dimensional topographies. In each draping experiment, an AZ5214-E sheet was: (1) formed floating on the water surface, (2) lowered onto a non-planar substrate, and (3) draped over it during drying. Self-sustained and conformal AZ5214-E layers were formed over the non-planar substrates depending on drying temperature. Interactions between water and AZ5214-E can result in the depression of the glass transition temperature T_g of AZ5214-E material during drying. Hence, an AZ5214-E sheet that was formed glassy can become rubbery. At room temperature T < T_g, the sheet is glassy, and it can form a self-sustained or bridging layer over a 3D topography. By contrast, at T ap or > T_g, the sheet becomes rubbery and mouldable by adhesion and capillary forces. As the result, it can contour a 3D topography