Abstract: A wafer transfer apparatus used in manufacturing high density semiconductor products is disclosed which includes at least three movable arms for supporting a wafer from below thereby preventing contact with the active surface of the wafer. A mechanism for moving the arms into and out of its wafer supporting position is diposed, in part, above the wafer when a wafer is supported thereby. The portions of the actuator mechanism disposed above the wafer are constructed in a way such that no sliding contact occurs between elements thereof. Sliding contact between elements disposed above a wafer has proved to produce microscopic particles which can fall onto the active surface of the wafer thereby contaminating the circuits contained thereon. As sliding contact is avoided by the apparatus of the present invention, contamination particles produced within the wafer transfer apparatus is substantially reduced, if not entirely eliminated.

Abstract: A system of interconnection of a set of coaxial cables to a device, such as a testing apparatus for an integrated circuit chip, includes an apertured plate of electrically conducting material which positions each of the connectors in registration with corresponding terminals of the device. Each connector includes a spring-loaded probe insulated from a housing of the connector and making connection between an inner conductor of a coaxial cable and the corresponding terminal of the device. Also included are signal-return spring-loaded probes mounted in the plate and electrically connected thereby to the other conductors of the coaxial cables to provide signal-return paths with corresponding terminals of the device. In alternative embodiments, a simpler connection is fashioned by use of a single connector and a single signal-return probe extending from a shoulder of the housing of the connector.

Abstract: A high precision, high throughput submicrometer workpiece positioning system, particularly useful as a workpiece positioning means in electron beam lithography tools. The positioning system increases mechanical stability by essentially eliminating mechanical hysteresis, which allows state of the art electron beam lithography systems to provide the repeatable, accurate and dense circuit patterns that modern semiconductor trends demand.The positioning system in preferred form comprises a movable positioning table, a workpiece supporting superstructure which is elastically joined to the movable positioning table by three geometrically distinct kinematic support means and a two-stage coupling means which mounts a workpiece (i.e., semiconductor mask or wafer) to the workpiece supporting superstructure. A laser interferometer locating-positioning system is utilized to position the workpiece. The interferometer mirrors are integral with the workpiece supporting superstructure.

Abstract: A communication system, adapted particularly for use in military tactical situations, includes a plurality of central stations and at least one remote station assigned to each such central station. Each central station includes an omnidirectional antenna and each remote station includes a directional antenna, directed toward the central station to which the remote station is assigned. Each central station transmits at a distinct frequency and each remote station assigned thereto receives at the frequency of its assigned central station and transmits at a different frequency, unique to itself. Transmission qualities between central stations is evaluated to optimize communication paths between remote stations.

Abstract: A coaxial line as a rigid probe interposer is particularly useful for connecting an electrical tester to a high speed integrated circuit utilizes two coaxial dielectrics for spacing a center conductor from an outer conductor in the form of a holed metallic body. The line center conductor is initially coated with a first dielectric. The dielectric coated center conductor is thereafter positioned in an oversized hole within the conductive body. The annular free space existing between the inside wall of the hole and the outer circumference of the first dielectric is filled as by capillary action, with a second, liquid dielectric which flows into the fissures and cracks within the first dielectric prior to curing.

Abstract: A slide plate hold-down spring is provided with a depending portion which is received in a well in a sewing machine bed. The depending portion includes a window in which a protuberance on the bed engages the spring, and a curved length which engages a wall of the well.

Abstract: An elevator drive shaft is air pressure counter-balanced and dampened under varying load and system pressure conditions by applying required air pressure to an appropriate side of a piston moving with the drive shaft in an electron beam semiconductor wafer writing apparatus vacuum chamber. Air pressure counterbalancing load forces minimize the actuating forces required to drive the elevator, substantially minimizing vibratory shock and distortion to the electron beam writing system and increasing speed of wafer movement. This permits electron beam writing on one wafer simultaneously with a load/unload operation of a second semiconductor wafer. The counter-balancing load forces also minimize the probability of accidental damage to the system or semiconductor wafers due to uncontrolled high forces or upon mechanical impact between moving and fixed parts, during apparatus malfunction.

Abstract: An electron beam vacuum chamber is provided with an elevator mechanism within the chamber including a platform closing off an opening within a horizontal vacuum chamber wall and separating the vacuum chamber from an overlying antechamber partially defined by a vertically displaceable lid overlying the opening and moving towards and away from the opening. Resilient peripheral seals are fixed to the lid facing the chamber wall and the elevator platform. A coil spring partially compressible upon contact with the first peripheral seal carried by the lid with the face of the vacuum chamber wall forms a first mechanical override and an annular spring metal diaphragm fixedly mounted about its outer peripheral edge to the vacuum chamber adjacent the opening has its inner peripheral edge freely flexible and is contacted by the resilient peripheral seal of the platform to form a second mechanical override.

Abstract: A digital system utilizing communication satellite links is arranged to minimize the satellite link transmission time delay variation and achieve bit synchronization of the incoming data to a common bit clock at a central tandem switching or collection center.The incoming data bit rate from each subsidiary center is monitored by suitable means such as a threshold detector to determine if the time delay rate is changing relative to the tandem center central timing. Each of the lines from every subsidiary center has minimal buffering means in the tandem center to absorb short-term changes in the input data rate. A message selecting and encoding network is provided in the tandem center for each subsidiary center to generate a return bit rate message to its respective subsidiary center. Each subsidiary center is provided with suitable decoders, logic, and an oscillator to change the data bit rate in response to the control message from the tandem center.

Abstract: A semiconductor wafer, which has chips formed thereon, is moved from a class 100 environment into a vacuum chamber in which pattern writing is performed on the chips by an electron beam without significantly affecting the vacuum level in the vacuum chamber. The wafer is initially disposed on an elevator, which is within the vacuum chamber, through an opening, which is vacuum sealed by the elevator at this time, in the top wall of the vacuum chamber. A lid is then placed over the opening from the exterior to cooperate with the elevator to form an ante chamber which the wafer disposed therein. The ante chamber, which is purged prior to the lid being placed over the opening, is then reduced to a vacuum of 5 .times. 10.sup..sup.-2 torr. The elevator then lowers the wafer into a horizonal plane in which a transfer mechanism is located to transfer the wafer from the elevator to an X-Y table on which the wafer is mounted for pattern writing of the chips. The transfer mechanism includes an arm, which is indexed 180.