Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: 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.

Abstract: This invention relates to an ion beam monitoring arrangement for use in an ion implanter where it is desirable to monitor the flux and/or a cross-sectional profile of the ion beam used for implantation. It is often desirable to measure the flux and/or cross-sectional profile of an ion beam in an ion implanter in order to improve control of ion implantation of a semiconductor wafer or similar. The present invention describes adapting the wafer holder to allow such beam profiling to be performed. The substrate holder may be used progressively to occlude the ion beam from a downstream flux monitor or a flux monitor may be located on the wafer holder that is provided with a slit entrance aperture.

Abstract: This invention relates to a method of implanting ions in a substrate using an ion beam where instabilities in the ion beam may be present and to an ion implanter for use with such a method. This invention also relates to an ion source for generating an ion beam that can be switched off rapidly. In essence, the invention provides a method of implanting ions comprising switching off the ion beam when an instability has been detected whilst continuing motion of the substrate relative to the ion beam to leave an unimplanted portion of a scan line across the substrate, establishing a stable ion beam once more and finishing the scan line by implanting the unimplanted portion of the path.

Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: An indirectly heated button cathode for use in the ion source of an ion implanter has a button member formed of a slug piece mounted in a collar piece. The slug piece is thermally insulated from the collar piece to enable it to operate at a higher temperature so that electron emission is enhanced and concentrated over the surface of the slug piece. The slug piece and collar piece can be both of tungsten. Instead the slug piece may be of tantalum to provide a lower thermionic work function. The resultant concentrated plasma in the ion source is effective to enhance the production of higher charge state ions, particularly P+++ for subsequent acceleration for high energy implantation.

Abstract: This invention is concerned with the control of implanting ions into a substrate, such as doping semiconductor wafers. The ion beam is measured to ensure waters are implanted with the correct, uniform ion dose. The incident ion beam comprises ions and neutrals, yet detectors measure only ions. The ions/neutrals ratio varies with the ion implanter's chamber pressure that in turn is known to rise and fall when the ion beam is on and off the wafer respectively, according to a characteristic time constant. This invention provides methods of correcting measured ionic currents to account for neutrals using the time constant. Initially an assumed time constant is used that is later improved by measuring the ionic current after a delay sufficient to allow the chamber pressure to recover to its base value. The time constant may also be improved by removing any quadratic variation in already determined true beam current values.

Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: An indirectly heated button cathode for use in the ion source of an ion implanter has a button member formed of a slug piece mounted in a collar piece. The slug piece is thermally insulated from the collar piece to enable it to operate at a higher temperature so that electron emission is enhanced and concentrated over the surface of the slug piece. The slug piece and collar piece can be both of tungsten. Instead the slug piece may be of tantalum to provide a lower thermionic work function. The resultant concentrated plasma in the ion source is effective to enhance the production of higher charge state ions, particularly P+++ for subsequent acceleration for high energy implantation.

Abstract: An implanter provides two-dimensional scanning of a substrate relative to an implant beam so that the beam draws a raster of scan lines on the substrate. The beam current is measured at turnaround points off the substrate and the current value is used to control the subsequent fast scan speed so as to compensate for the effect of any variation in beam current on dose uniformity in the slow scan direction. The scanning may produce a raster of non-intersecting uniformly spaced parallel scan lines and the spacing between the lines is selected to ensure appropriate dose uniformity.

Abstract: 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.

Abstract: An indirectly heated button cathode for use in the ion source of an ion implanter has a button member formed of a slug of tantalum mounted in a collar of tungsten. The lower thermionic work function of tantalum causes electron emission to be concentrated over the surface of a tantalum slug. The tantalum slug may be mounted to enable it to operate at a higher temperature compared to the surrounding tungsten collar portion. The resultant concentrated plasma in the ion source is effective to enhance the production of higher charge state ions, particularly P+++ for subsequent acceleration for high energy implantation.

Abstract: 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.

Abstract: 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.

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: A charge exchange cell for ion implanters employing a tandem accelerator has a hollow-wall construction with a heating element inserted inside the hollow wall.