Abstract: A non-contacting, non-clogging, electro-mechanically operated marking device or inker for continuous or intermittently marking a semiconductor wafer die is disclosed together with a method of operating the device. The marking device has an ambient pressure ink reservoir within which is mounted a thin, capillary filament guide tube. A length of filament such as, fishline, is positioned within the tube and secured at one end to the plunger of a solenoid. The distal end of the filament is driven out of the capillary tube by the solenoid to force a small amount of the marking fluid or ink out of the reservoir and onto the die without the filament contacting the die. The solenoid coil is energized by a current pulse having a first current level and a second current level that is less than the first current level. The second current level provides a short holding current for the solenoid to prevent spattering of the marking fluid.

Abstract: A method and apparatus for damping stepper motors are disclosed. A tachometer feedback is used to modulate the phase angle of the stepper motor command currents to achieve damping.

Abstract: An automatic wafer loading and pre-alignment system for integrated circuit wafer-mask Aligners. A belt feed track system is employed to transport wafers from a "send" wafer storage carrier to a wafer pre-alignment station. The wafer is machanically pre-aligned with respect to the wafer chuck of the Aligner by means of a roller arm and flat-finder system. After completion of the pre-alignment process, the Aligner turntable is rotated to carry the pre-aligned wafer and chuck to the home position of the turntable and at the same time position another chuck at the pre-alignment station. If the new chuck at the pre-alignment station contains a wafer, the wafer is transported from the chuck to a "receive" wafer storage carrier by means of a belt return track system. The feed and return wafer belt track systems have a common portion between the pre-alignment station and the respective "send" and "receive" wafer storage carriers.

Abstract: An air bearing piston assembly for semiconductor mask-to-wafer aligner which utilizes a plurality of air bearings to produce a very low friction and a very predictable force system for bringing a mask into contact and level with a semiconductor wafer. Two small driver pistons are employed to move a main piston. An outside air bearing between a rotation clamp ring and the main piston and an inside air bearing between a piston guide and the main piston produce an almost frictionless system. A third air bearing is established between a leveling ball and the ball table so that the wafer with the chunk can level accurately with a minimum of force against the mask.

Abstract: A non-planar semiconductor wafer chuck having a plurality of outwardly extending channels in the chuck face and a plurality of vacuum/pressure ports extending through the chuck and communicating with the face thereof. When a semiconductor wafer is positioned with respect to an overlying photomask by the chuck, atmospheric pressure is applied to the centrally located port or ports and a vacuum is applied to the peripheral ports of the chuck. The resulting pressure differentials acting in concert with a surrounding vacuum chamber causes the central portion of the wafer to rise against the photomask while the peripheral portions of the wafer are drawn down into the channels. At this point in the operational sequence, the normally trapped nitrogen can escape through breaks in the peripheral seal between the mask and wafer which are formed by the downwardly extending wafer surface in each channel.

Abstract: A thermocompression, tailless wire bonder which permits the bonding operation to take place at any location along the path of the bonding tool without affecting the length of wire protruding below the bonding tool or the location of the end of the wire relative to the torch. A non-frictional wire tensioning device is employed to produce a constant and adjustable tension on the bonding wire. A virtual image, parallax free, optical positioning system is utilized to position the bonding tool.