Issue Information

Cover Photograph: Top: The schematic representation of the experimental process followed in the present work to fabricate the through-holes in the glass wafers using the masking layer composed of Cr thin film and positive photoresist (AZ1512HS), (A) 4-inch and 500 μm thick Borofloat glass wafer, (B) Deposition of Cr thin film using DC magnetron sputtering method, (C) Deposition of positive photoresist using spin coating method, (D) Transfer of through-hole patterns utilizing UV exposure through a photomask with desired mask opening diameters, (E) Development of photoresist in developer solution, (F) Selective etching of Cr thin film in freshly prepared Cr etchant, (G) Etching of glass wafer in 25% or 30% HF by placing it in a custom made wafer holder, and (H) Resulting glass wafer with fabricated through-holes after complete removal of the demonstrated masking layer. Bottom: Scanning electron microscopy (SEM) images showing the Borofloat glass wafer surface and the through-holes of various dimensions that are fabricated in Borofloat glass using (A–C) 25% hydrofluoric acid (HF) and (D–F) 30% HF, respectively. These images are captured after completely removing the masking layer. The diameters given in the SEM images (e.g., 0.4 mm diameter) correspond to the designed mask opening diameters.