Abstract: The present invention relates to ion sources (14) comprising a cathode (20) and a counter-cathode (44) that are suitable for ion implanters (10). Typically, the ion source is held under vacuum and produces ions using a plasma generated within an arc chamber (16). Plasma ions are extracted from the arc chamber and subsequently implanted in a semiconductor wafer (12). The ion source according to the present invention further comprises a cathode (40) arranged to emit electrons into the arc chamber; an electrode (44) positioned in the arc chamber such that electrons emitted by the cathode are incident thereon; one or more voltage potential sources (76) arranged to bias the electrode; and a voltage potential adjuster (82) operable to switch between the voltage potential source biasing the electrode positively thereby to act as an anode and the voltage potential source biasing the electrode negatively thereby to act as a counter-cathode.

Abstract: The present invention relates to components in an ion implanter that may see incidence of the ion beam, such as a beam dump or a beam stop. Such components will be prone to the ions sputtering material from their surfaces, and sputtered material may become entrained in the ion beam. This entrained material is a source of contamination. The present invention provides an ion implanter comprising power supply apparatus and an ion-receiving component. The component has an opening that receives ions from an ion beam such that ions strike an internal surface. The power supply apparatus is arranged to provide an electrical bias to the internal surface to decelerate the ions prior to their striking the surface, thereby mitigating the problem of material being sputtered from the surface.

Abstract: A guide tube for an ion beam in an ion implanter which is located adjacent a semiconductor wafer being implanted has an outwardly tapering central bore, thereby alleviating problems of beam strike as the ion beam passes through the guide tube.

Abstract: The present invention relates to components in ion implanters having surfaces, such as graphite surfaces, adjacent to the path of the ion beam through the ion implanter. Such surfaces will be prone to sputtering, and sputtered material may become entrained in the ion beam. The present invention sees the use of surfaces that are formed so as to present a series of angled faces that meet at sharp intersections. In this way, any material will be sputtered away from the ion beam.

Abstract: Components in an ion implanter that may see incidence of the ion beam include a chamber having an elongate slot opening defined by edges so that a central portion of the ion beam enters the component through the opening with the edges clipping at least a peripheral portion of the ion beam. The arrangement mitigates the problem of sputtered material escaping back out from the component and becoming entrained in the ion beam.

Abstract: A scanning arm assembly for multi-directional mechanical scanning of a semiconductor wafer or other substrate to be implanted includes a pair of drive arms connected by two linkage arms to form a quadrilateral. Rotary joints are provided to join adjacent arms together, and a substrate holder is provided on one linkage arm where it joins the other linkage arm. Thus, rotating the drive arms causes the substrate holder to move. Suitable control of the drive arms allows the substrate holder to be moved through an ion beam to follow many different paths and hence implant patterns.

Abstract: A substrate holding apparatus for use in ion implanters includes two or more substrate holders that can adopt interchangeable positions, thereby allowing one substrate holder to scan a substrate through an ion beam while substrates can be swapped on the other substrate holder. The substrate holder assembly includes a base rotatable about a first axis and at least two support arms extending from the base to ends provided with substrate holders. Rotating the base allows the substrate holders to move between designated positions. One designated position may correspond to a position for implanting a substrate and another designated position may correspond to a loading/unloading station.

Abstract: A method of tuning an ion beam in an ion implanter relative to, e.g., ion beam current, energy, size and shape, includes retrieving a set of parameters associated with operation of the ion implanter, at least some of which are stored in a dynamic database, configuring the ion implanter according to the retrieved set of parameters, to thereby provide an ion beam, optimizing the ion beam by varying one or more of the parameters, and updating the parameters stored in the dynamic database which changed during optimization.

Abstract: The invention relates to improving the efficiency of ion flow from an ion source, by reducing heat loss from the source both in the ion chamber of the ion source and its constituent parts (e.g. the electron source). This is achieved by lining the interior of the ion chamber and/or the exterior with heat reflective and/or heat insulating material and by formation of an indirectly heated cathode tube such that heat transfer along the tube and away from the ion chamber is restricted by the formation of slits in the tube. Efficiency of the ion source is further enhanced by impregnating and/or coating the front plate of the ion chamber with a material which comprises an element or compound thereof, the ions of which element are the same specie as those to be implanted into the substrate from the source thereof.

Abstract: 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.

Abstract: The present invention relates to a guide tube for an ion beam in an ion implanter located adjacent a semiconductor wafer. Such guide tubes are provided to confine charged particles used for wafer neutralisation during implantation. According to the invention, a guide tube comprises an axis, open ends to receive an ion beam along said axis, a tube wall substantially parallel with said axis, and at least one opening through the tube wall forming a gas conduction passage from inside to outside the guide tube, said passage having a length aligned at an acute angle to said guide tube axis and a minimum dimension transverse to said length such that a line of sight through the passage perpendicular to said guide tube axis is substantially occluded.

Abstract: Monotomic dopant ions for ion implantation are supplied from vapour of a species containing plural atoms of the desired dopant. The vapour is fed to a plasma chamber and a plasma produced in the chamber with sufficient energy density to disassociate the vapour species to produce monatomic dopant ions in the plasma for implantation.

Abstract: This invention relates to a method of measuring a property of an ion beam, for example an ion beam current profile or the emittance of an ion beam. A Faraday array comprising an array of ion beam current sensors is employed. The array can provide an ion beam current profile at the plane of the array. The Faraday array is also used in conjunction with an occluding element that may be moved through the ion beam upstream of the Faraday array, there obscuring varying portions of the ion beam from the Faraday array. Suitable manipulation of the signals from the Faraday allows the ion beam current profile to be determined for the plane of the occluding element, and also for the emittance of the ion beam at the plane of the occluding element to be determined.

Abstract: A wafer support for an ion implanter includes a wafer holder and a support arm for the holder in the implant chamber. A portion of the support arm adjacent the wafer holder is at least intermittently exposed to the ion beam during implantation, as a result of the relative scanning of the ion beam and the wafer holder. An arm shield mechanism has a plurality of shielding surfaces which can be selectively disposed to receive the ion beam to protect the exposed portion of the support arm. The shielding surfaces may form a sleeve arranged over the arm which may be rotatable above the arm to present selected surfaces to the ion beam. Cross contamination when successively implanting different species can be reduced by presenting different shield surfaces to the beam.

Abstract: The invention relates to methods of controlling the effect of ions of an ionisable source gas that can react with interior surfaces of an arc chamber, by introducing ions of a displacement gas into the arc chamber, where the displacement gas ions are more chemically reactive with the material of the interior surfaces than the ions of the source gas. The source gas ions may typically be oxygen ions and the displacement gas ions are then typically fluorine ions where the interior surfaces comprise tungsten. The fluorine ions may, by way of example, be sourced from fluorine, silicon tetrafluoride or nitrogen trifluoride.

Abstract: A particle monitor in the process chamber of a semiconductor device manufacturing apparatus provides a measure of a flux of contaminant particles in the chamber. The flux is measured whilst process conditions are produced in the process chamber and a process parameter is adjusted in response to the measured flux in order to reduce this flux during the process. In an ion implanter, the particle sensor measures the flux of particles entrained with the ion beam at a location in front of the wafer being processed.

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: Monotomic boron ions for ion implantation are supplied from decaborane vapour. The vapour is fed to a plasma chamber and a plasma produced in the chamber with sufficient energy density to disassociate the decaborane molecules to produce monatomic boron ions in the plasma.

Abstract: An end station for an ion implanter has a vacuum chamber which receives an ion beam. A wafer holder is mounted at the distal end of a scanning arm which has its proximal end attached to the chamber wall. The scanning arm has at least two rotary joints providing articulation of the arm to permit movement of the wafer holder in two orthogonal scan directions in a scan plane transverse to the beam path through the vacuum chamber. A scanning arm driver moves the substrate holder in the scan plane in a desired two-dimensional scan pattern relative to the beam path.

Abstract: A gripper for loading wafers onto an implant wheel W and removing them from the wheel. The gripper having a substrate engaging mechanism (14) for engaging the substrate and a means for rotating this substrate engaging mechanism, such that wafers can be removed from the implant wheel, rotated to a second orientation and replaced without leaving the process chamber.