Abstract: A unique photoresist process is provided which achieves clean and complete lift-off of a thin film layer such as a sputtered thin film formed on a photoresist which is formed above a semiconductor substrate. The process of the present invention relies on a reentrant photoresist profile which breaks the continuity of the thin film layer. Accordingly, the process of the present invention ensures a clean lift-off. The desired photoresist profile which breaks the continuity of the thin film layer can be obtained by a typical photoresist process preceded by an oxidation process that takes place on the surface of the semiconductor substrate. The oxidation process provides a thin native oxide layer with thickness ranging from about 30 to 50 .ANG.. No extra processing steps involving dielectric film deposition and etch are required to achieve clean lift-off. Nevertheless, the process of the present invention ensures the clean lift-off of the thin film layer.

Abstract: A method of fabricating a self-aligned double gate recess profile in a semiconductor substrate is disclosed in which a first mask layer is formed over the substrate. A second mask layer having an opening is formed over the first mask layer. An opening at least as wide as the second mask layer's opening is formed through the first mask layer to expose the substrate beneath the second mask layer's opening. A first recess is etched in the semiconductor through the second mask layer's opening. The first mask layer's opening is then uniformly expanded and a wider recess, aligned to the first recess, is then formed in the semiconductor. The method is particularly applicable to the formation of self-aligned gate and channel recesses in a GaAs MESFET.

Abstract: A semiconductor substrate is etched in a two-step sequence, with two different liquid etchants that have different lateral etch rates. The relative time periods for which the etchants are applied are selected to achieve a close match between the actual etch profile and the desired profile. The process is particularly applicable to the formation of a gate recess in a GaAs MESFET for high power amplification.

Abstract: An I.C. insertor/extractor, which can press I.C.s on and extract the I.C.s from a printed circuit board, having an elongate handgrip element a clipping element, and a cap having a stem on its bottom end. The lower portion of the stem is maintained in the enlarged bore of the elongate body since a first C-ring is received by a groove disposed at a lower portion of the stem. The clipping element has a clipping housing with a cylindrical protrusion to be lodged in the elongate body. A spring-loaded rivet is retained within the cylindrical protrusion by a second C-ring mounted in a channel disposed at a bottom end of the cylindrical protrusion. A pair of pinching elements which are combined by a spring element is disposed under the rivet and a plate below the pinching elements has a hole on the center position of the plate to receive the rivet.