Abstract: A system for mounting VLSI devices on a substrate is disclosed, offering a high contact density. Each package consists of a semiconductor device having protruding elongated contact pin (2) on its surface and a wiring substrate having a cavity (3) on its surface. The cavities are filed with a conductive material (7) of a low melting point composition and sealed with a thin non-conductive foil (4). During packaging, the contact pins are made to penetrate the foil, and extend into the conductive alloy, thus making electrical contact therewith. To ease the penetration of the foil, the contact pins could be set into oscillating motion by means of an ultrasonic generator.

Abstract: The compressor cascade comprises a plurality of tandem-connected membrane pumps, each of the pumps having a plurality of stroke chambers whose volumes decrease in the direction of the fluid flow through the pumps. Each chamber has several parallel-connected input/output channels for interconnecting the individual membrane pumps and a check valve in each input/output channel for forcing the fluid in a specified direction. By electrostatic attraction forces, the membranes in the pumps are energized synchronously to resonance oscillations of the same frequency and deflection, building up the necessary operating pressure as the fluid is moved from the stroke chamber of one membrane pump into the smaller volume stroke chamber of the next succeeding membrane pump. The movement of the fluid through the membrane pumps of the compressor cascade leads to its compression, and the pressure at the end of the cascade is related to the reduction in volume of each succeeding stroke chamber.

Abstract: A circuit arrangement is provided for the continual operation monitoring and error diagnosis of a stepper motor controllable at its windings by control logic and driver stages using stepping pulses which are phase-shifted relative to each other. A multi-stage ring counter is used for logically representing the desired values of the stepping pulses with the ring counter under control of the stepping control pulses applied to the input of the control logic stage. A multi-stage compare circuit arrangement is used to compare the logical values of the stepping pulses from the ring counter with the logical values of the output signals from both the control logic stage and driver stage.