摘要:
A d. c. charged particle accelerator comprises accelerator electrodes separated by insulating spacers defining acceleration gaps between adjacent pairs of electrodes. Individually regulated gap voltages are applied across each adjacent pair of accelerator electrodes. In an embodiment, direct connections are provided to gap electrodes from the stage points of a multistage Cockcroft Walton type voltage multiplier circuit. The described embodiment enables an ion beam to be accelerated to high energies and high beam currents, with good accelerator stability.
摘要:
A hydrogen ion implanter for the exfoliation of silicon from silicon wafers uses a large scan wheel carrying 50+ wafers around its periphery and rotating about an axis. In one embodiment, the axis of rotation of the wheel is fixed and a ribbon beam of hydrogen ions is directed down on a peripheral edge of the wheel. The ribbon beam extends over the full radial width of wafers on the wheel. The beam is generated by an ion source providing an extracted ribbon beam having at least 100 mm major cross-sectional diameter. The ion source may use core-less saddle type coils to provide a uniform field confining the plasma in the ion source. The ribbon beam may be passed through a 90° bending magnet which bends the beam in the plane of the ribbon.
摘要:
A vacuum bearing structure comprises a combination of a planar gas bearing with a differentially-pumped vacuum seal. The bearing surface and the vacuum seal surfaces are formed of a porous material divided into a first outer region through which bearing gas can percolate to provide support and an inner second region providing the vacuum seal. An exhaust groove separates the two regions so that bearing gas can flow to atmosphere. The resulting structure can operate at a lower fly height to reduce loading on the differentially-pumped vacuum seal. The structure is particularly useful for motion feedthroughs into vacuum processes such as ion implantation.
摘要:
A vacuum seal and fluid bearing apparatus for reducing the distortion of the bearing surfaces of a gas bearing is described. The apparatus includes a stator attached around an aperture in a vacuum housing and having a first planar fluid bearing surface. A movable member for closing the vacuum housing aperture having a second fluid bearing surface extending parallel to the first bearing surface is adapted to be supported spaced from the first bearing surface by a bearing fluid. A vacuum seal is provided between the movable member and the stator. In use, a force due to atmospheric pressure acts on the movable member in a direction normal to the bearing surfaces and a movable member includes a pressure relief structure to reduce any bending moment produced in the movable member by the force.
摘要:
A d. c. charged particle accelerator comprises accelerator electrodes separated by insulating spacers defining acceleration gaps between adjacent pairs of electrodes. Individually regulated gap voltages are applied across each adjacent pair of accelerator electrodes. In an embodiment, direct connections are provided to gap electrodes from the stage points of a multistage Cockcroft Walton type voltage multiplier circuit. The described embodiment enables an ion beam to be accelerated to high energies and high beam currents, with good accelerator stability.
摘要:
A hydrogen ion implanter for the exfoliation of silicon from silicon wafers uses a large scan wheel carrying 50+ wafers around its periphery and rotating about an axis. In one embodiment, the axis of rotation of the wheel is fixed and a ribbon beam of hydrogen ions is directed down on a peripheral edge of the wheel. The ribbon beam extends over the full radial width of wafers on the wheel. The beam is generated by an ion source providing an extracted ribbon beam having at least 100 mm major cross-sectional diameter. The ribbon beam may be passed through a 90° bending magnet which bends the beam in the plane of the ribbon. The magnet provides intensity correction across the ribbon to compensate for the dependency on the radial distance from the wheel axis of the speed at which parts of the wafers pass through the ribbon beam.
摘要:
A hydrogen ion implanter for the exfoliation of silicon from silicon wafers uses a large scan wheel carrying 50+ wafers around its periphery and rotating about an axis. In one embodiment, the axis of rotation of the wheel is fixed and the wheel is formed with tensioned spokes supporting a rim carrying the wafer supports. The spokes may be used for carrying cooling fluid to and from the wafer supports. Detachable connections in the cooling fluid conduits in the vacuum chamber may comprise tandem seals with an intermediate chamber between them which can be vented outside the vacuum chamber, or independently vacuum pumped. In one embodiment, a ribbon beam of hydrogen ions is directed down on a peripheral edge of the wheel. The ribbon beam extends over the full radial width of wafers on the wheel.
摘要:
A hydrogen ion implanter for the exfoliation of silicon from silicon wafers uses a large scan wheel carrying 50+ wafers around its periphery and rotating about an axis. In one embodiment, the axis of rotation of the wheel is fixed and the wheel is formed with tensioned spokes supporting a rim carrying the wafer supports. The spokes may be used for carrying cooling fluid to and from the wafer supports. Detachable connections in the cooling fluid conduits in the vacuum chamber may comprise tandem seals with an intermediate chamber between them which can be vented outside the vacuum chamber, or independently vacuum pumped. In one embodiment, a ribbon beam of hydrogen ions is directed down on a peripheral edge of the wheel. The ribbon beam extends over the full radial width of wafers on the wheel.
摘要:
A wafer holder assembly includes first and second main structural members from which first and second wafer-holding arms extend. The first arm is secured to the main structural members by a graphite distal retaining member. The second arm is pivotally biased to a wafer-hold position by a graphite bias member. This arrangement provides a conductive path from the wafer to the assembly for inhibiting electrical discharges from the wafer during the ion implantation process. The assembly can further include additional graphite retaining members for maintaining the structural integrity of the assembly during the extreme conditions associated with SIMOX wafer processing without the need for potentially wafer-contaminating adhesives and conventional fasteners. The wafer-contacting pins at the distal end of the arms can be formed from silicon. The silicon pins can be coated with titanium nitride to enhance electrical contact with the wafer and to provide an abrasion resistant surface. The pins can have a limited profile to minimize the amount of pin material proximate the wafer for reducing the likelihood of electrical arcing from the wafer to the pin.
摘要:
An ion source assembly 10 is disclosed, the assembly comprising a source sub assembly having an ion source 20, an extraction electrode 40 and an electrically insulating high voltage bushing 60 to support the extraction electrode 40 relative to the ion source 20. The ion source assembly further includes a chamber 70 having an exit aperture to allow egress of ions to an ion implanter. The chamber 70 encloses one or more further electrodes 80,90. The source sub assembly is mounted to the chamber 70 via a hinge 150. This allows ready access to the inner walls of the chamber 70, which in turn allows easier maintenance and cleaning of the further electrodes 80,90 as well as the inner walls of the chamber 70. Preferably, a liner 160 is employed on the inner walls of the chamber 70.