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:
This invention relates to a method of scanning a substrate through an ion beam in an ion implanter to provide uniform dosing of the substrate. The method comprises causing relative motion between the substrate and the ion beam such that the ion beam passes over all of the substrate and rotating the substrate substantially about its centre while causing the relative motion. Rotating the substrate while causing the relative motion between the substrate and the ion beam has several advantages including avoiding problematic angular effects, increasing uniformity, increasing throughput and allowing a greater range of ion beam profiles to be tolerated.
摘要:
A fluid bearing vacuum seal assembly comprises an annular stator with first and second opposed surfaces, at least part of the first surface defining a first bearing surface. The stator also defines an aperture having a wall extending between the first and second surfaces. The assembly also comprises a rotor with first and second opposed surfaces, the second surface defining in part a second bearing surface which is supported relative to the first bearing surface in use so that the rotor is rotatable relative to the stator. A cylindrical wall projects axially from the second surface of the rotor through the aperture in the stator. An annular flange projects radially outwardly from the cylindrical wall adjacent to the second surface of the stator. At least one annular differential pumping channel is defined in each of the first and second surfaces of the stator and the wall which connects the first and second surfaces. This configuration allows the differential pumping channels to be spaced apart to a greater extent, improving the performance of the vacuum seal and allowing a better vacuum to be achieved.
摘要:
Semiconductor processing apparatus is disclosed which provides for movement of a scanning arm 60 of a substrate or wafer holder 180, in at least two generally orthogonal directions (so-called X-Y scanning). Scanning in a first direction is longitudinally through an aperture 55 in a vacuum chamber wall. The arm 60 is reciprocated by one or more linear motors 90A, 90B. The arm 60 is supported relative to a slide 100 using gimballed air bearings so as to provide cantilever support for the arm relative to the slide 100. A compliant feedthrough 130 into the vacuum chamber for the arm 60 then acts as a vacuum seal and guide but does not itself need to provide bearing support. A Faraday 450 is attached to the arm 60 adjacent the substrate holder 180 to allow beam profiling to be carried out both prior to and during implant. The Faraday 450 can instead or additionally be mounted adjacent the rear of the substrate holder or at 90° to it to allow beam profiling to be carried out prior to implant, with the substrate support reversed or horizontal and out of the beam line.
摘要:
This invention relates to a method of scanning a substrate through an ion beam in an ion implanter to provide uniform dosing of the substrate. The method comprises causing relative motion between the substrate and the ion beam such that the ion beam passes over all of the substrate and rotating the substrate substantially about its centre while causing the relative motion. Rotating the substrate while causing the relative motion between the substrate and the ion beam has several advantages including avoiding problematic angular effects, increasing uniformity, increasing throughput and allowing a greater range of ion beam profiles to be tolerated.
摘要:
An ion electrode extraction assembly comprising an ion source 20 and at least one electrode 50 having a gap through which a beam of extracted ions passes in use. An electrode manipulator assembly 55 is provided to move the electrode so as to vary the width of the gap transversely to the ion beam, move the electrode transversely to the ion beam, and move the electrode in the direction of the ion beam. The three degrees of movement being carried out independently of one another.
摘要:
A fluid bearing and seal for an ion implanter is disclosed. The fluid bearing has a stator attached to a base and a moving member provided over the stator so that a fluid bearing can be formed between the opposing surfaces of the stator and the moving member. Either the base or the stator has a locating member extending normal to the bearing surface and the other one of either the base or the stator has a recess shaped to receive the locating member. A fluid seal enables the member to slide in the recess in the normal direction to seal off an enclosed volume between the member and the other one of either the stator or the base. A plurality of fixtures are distributed at points in a plane parallel to the bearing surface to fix the locating member and the other one of either the stator or the base together at these points to form the enclosed volume. The number of the fixtures is the minimum necessary so that the bearing surface of the stator remains undistorted. A fluid controller controls the supply of a fluid to the enclosed volume to maintain the planar bearing surface undistorted under the loading of the moving member.
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.