Abstract: A non-destructive ion dose monitor senses instantaneous dose increment in respect of a secondary radiation from known instantaneous coordinates of the ion beam, and a dose image distribution function of workpiece surface coordinates is accumulated in a memory. At intervals, the dose image is compared with a preselected desired dose distribution to obtain a difference distribution function of the ion beam scanning coordinates. The subsequent scanning regime is altered in accord with the difference distribution to cause the sensed dose image to converge with the desired distribution.

Abstract: Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feedback the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the cyclic sequence is accomplished at the expiration of a preselected number of complete cycles.

Abstract: Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feedback the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of a selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the cyclic sequence is accomplished at the expiration of a preselected number of complete repetitions of the cyclic sequence.

Abstract: An end station for a material treatment apparatus such as ion implantation system employs a dish shaped disc for sequentially presenting a plurality of semiconductor wafers arranged on the periphery of the disc to an ion beam. Coolant is circulated via rotating joints through channels in a disc to maintain same at a preselected base temperature. A thin layer of thermally conductive resilient material is disposed between each semiconductor wafer and the disc. Centrifugal force acting to press the wafer against the resilient material establishes good thermal contact therebetween and further compression of the resilient material increases the thermal conductance of the layer whereby the temperature of the wafers under implantation is selectably controlled.

Abstract: Precise control of radiation dose distribution over the surface of a workpiece is obtained by differential scanning in accord with a density of scanning traces function. This may be accomplished by differential repetition of the trace in the incremented area dA at generalized coordinates (p,q) of the surface, by frequency modulation of the waveform(s) controlling the scan, by spatial modulation of the scan through choice of scan pattern, or by combinations of these approaches.

Abstract: Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feedback the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of a selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the repetitions of the cyclic sequence is accomplished at the expiration of a preselected number of complete cycles.