Abstract: Thinned-portion substrates and processing of thinned-portion substrates is provided. A portion of a substrate, such as a mother glass used in touch screen manufacturing, can be thinned by forming a cavity in a surface of the substrate. Surface structures, such as touch sensing circuitry and/or display circuitry, can then be formed on the thinned portion of the substrate. For example, touch screen components can be formed as surface structures including touch sensing circuitry and display circuitry on one or more thinned substrate portions through processes including depositing, masking, etching, doping, etc. The thinned substrate portion, including the surface structures formed thereon, can then be detached from the surrounding thicker part of the substrate. In this way, for example, the surrounding thicker part of the substrate can provide structural integrity during various other manufacturing processes, while allowing surface structures to be formed directly on a thinner substrate.