Abstract: An ion implanter comprises an ion beam generator to generate a beam of ions to be implanted which are directed into a process chamber. A scanning device is provided which is movable in linear reciprocating motion along a first axis relative to said process chamber. A wafer support structure having a longitudinal axis is mounted within the process chamber with the axis substantially horizontal. An end of the wafer support structure protrudes out of the process chamber through an aperture in its wall and is secured to the scanning device. At least one piston is attached to the end of the wafer support structure and is slidably received in at least one cylinder for reciprocating movement along a second axis parallel to the first axis. The cylinder has a first end which is open to allow atmospheric pressure to act on the piston, and the chamber within the cylinder enclosed by the piston is evacuated in use.

Abstract: An ion implantation system for producing silicon wafers having relatively low defect densities, e.g., below about 1×106/cm2, includes a fluid port in the ion implantation chamber for introducing a background gas into the chamber during the ion implantation process. The introduced gas, such as water vapor, reduces the defect density of the top silicon layer that is separated from the buried silicon dioxide layer.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for reducing heating of a workpiece during ion implantation. The method comprises generating an ion beam for implantation of ions into a workpiece is, the workpiece having a surface defining a plane; scanning the ion beam relative to the surface of the workpiece in a first direction in the plane; repeatedly reciprocating the workpiece in a second direction transverse to the first direction to traverse to and from through the scanned ion beam; and rotating the workpiece 180 degrees about a central axis of the workpiece between each successive traverse of the wafer through the scanned ion beam, so that the wafer always presents the same leading edge to the beam on each traverse.

Abstract: An ion implantation system for producing silicon wafers having relatively low defect densities, e.g., below about 1×106/cm2, includes a fluid port in the ion implantation chamber for introducing a background gas into the chamber during the ion implantation process. The introduced gas, such as water vapor, reduces the defect density of the top silicon layer that is separated from the buried silicon dioxide layer.

Abstract: An apparatus used to control a workpiece inside a vacuum chamber. The workpiece is supported on a workpiece holder in the vacuum chamber. The workpiece is isolated from the atmosphere outside of the vacuum chamber by differentially pumped vacuum seals and an integral air bearing support. The differentially pumped vacuum seals and integral air bearing support allow for multiple independent motions to be transmitted to the workpiece supported by the workpiece holder. The workpiece holder motions provided are (1) rotation about the X axis, (2) translation back and forth along the Y direction of an X-Y plane on the surface of the workpiece holder, and (3) rotation of the workpiece in the X-Y plane about its Z axis. Concentric seals, oval for the translation motion and circular for the rotational motion, are differentially pumped through common ports to provide successively decreasing pressure and gas flow in order to reduce the gas load into the vacuum vessel to a negligible rate.

Abstract: An apparatus used to control a workpiece inside a vacuum chamber. The workpiece is supported on a workpiece holder in the vacuum chamber. The workpiece is isolated from the atmosphere outside of the vacuum chamber by differentially pumped vacuum seals and an integral air bearing support. The differentially pumped vacuum seals and integral air bearing support allow for multiple independent motions to be transmitted to the workpiece supported by the workpiece holder. The workpiece holder motions provided are (1) rotation about the X axis, (2) translation back and forth along the Y direction of an X-Y plane on the surface of the workpiece holder, and (3) rotation of the workpiece in the X-Y plane about its Z axis. Concentric seals, oval for the translation motion and circular for the rotational motion, are differentially pumped through common ports to provide successively decreasing pressure and gas flow in order to reduce the gas load into the vacuum vessel to a negligible rate.

Abstract: A target chamber for a mechanically scanned ion implanter in which semiconductor wafers are maintained in contact with a rotating target disk entirely by body forces, thus eliminating the need for clamping members contacting the wafer surface. The axis of the disk is inclined, and the disk is in the form of a shallow dish having an inclined rim with cooled wafer-receiving stations formed on the inner surface of the rim. Centrifugal force is relied on to force the wafers against the cooled disk. Each wafer-receiving station includes fence structures which are engaged by the wafer during loading and when the disk is spinning. The fence structures are resilient so that wafer damage and thus particulate contamination is minimized. In accordance with another aspect of the invention the ion beam is projected against the wafers obliquely to the radius of the disk as to minimize striping effects and overscan.

Abstract: In apparatus for controlling the treatment of a workpiece by a beam emanating from a source, there is translational relative movement in two orthogonal directions between the beam and the workpiece support element, and control of velocity in one (control) direction occurs in response to a detector, mounted behind the support, which periodically samples the beam through a moving slot in the support element. This slot extends over the range of movement in the control direction. An ion implanter is shown in which the support element is a constantly spinning disk the axis of which is translated in the control direction. Another ion implanter is shown in which the support element is a moving belt. A simple control circuit, useful for both embodiments, achieves a uniform ion dosage upon semiconductor substrates at a high production rate despite variations in beam intensity. The detector is not affected by a shower of electrons upon the support that neutralizes charge on the workpieces.

Abstract: Apparatus for directing a beam at a workpiece in vacuum has a special planar sliding multiple seal arrangement that enables repeated scanning movement of the workpiece across the beam. The seal includes a planar slide plate and an opposed relatively movable seal support member, also preferrably a plate parallel to the slide plate. Aligned apertures are in the members, one of which is larger in the direction of relative movement than the other enabling the relative movement while maintaining the alignment. A plurality of concentric resilient seals, which may be of oval race track configuration, bear with a sliding contact against the planar surface, these seals preferably comprising composites of a thin high density polyethylene seal element and a soft and only milding compressed backing element that applies a feather-light seal pressure. Between-seal pumping is provided to reduce the differential pressure across any seal to to remove gas that may leak into the space.

Abstract: Ion implantation equipment of the spinning disk type has an automated disk exchange system employing a pair of arms that interchange disks between a pair of exchange stations. One exchange station is defined by a back cover of a target chamber that hinges down. The disk drive motor is mounted on that cover and introduces water cooling for the disk through the drive shaft. Heat conductive elastomeric material interposed between the disk and its support on the shaft ensures good heat transfer from the disk in a high vacuum environment. The exchange system employs linear and rotary actuators of the fluid cylinder type, and the pickup head employs a pneumatic robot that operates a toggle clamp that secures the disk for its scanning rotation.

Abstract: An apparatus for distributing a beam substantially uniformly over a workpiece comprising a workpiece holder, first means for rotating the holder in a generally circular path about a first axis which is generally perpendicular to the axis of the beam, second means for counter-rotating the holder about a second axis parallel to the first axis at a rate dependent upon the rate of rotation of the holder about the first axis to provide, in cooperation with the first means, a constant orientation of the holder relative to the beam, and third means for producing relative motion between the workpiece and the beam in a direction parallel to the first axis.

Abstract: An isolation lock through which a workpiece item can move in a path between first and second regions at different pressures, the lock comprising a housing having an upper item entrance and a lower item exit at opposite sides of the housing, a movable member within the housing defining an item-receiving surface disposed substantially in a plane which lies at a constant acute angle to the horizontal regardless of its position to enable gravity movement of the workpiece over the surface, the member movable to translate the item-receiving surface between upper and lower positions in which, respectively, the uppermost portion of the surface is adjacent the entrance to receive the workpiece and the lowermost portion of the surface is adjacent the exit to deliver the workpiece and means providing an air-tight seal between the exit and the surface when the surface is in its upper position and between the entrance and the surface when the surface is in its lower position.