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: A vaporizer generating feed gas for the arc chamber of an ion source has a crucible which is heated to a temperature at which material in the crucible sublimes to produce a vapour for use as the feed gas. In addition to the heating element for heating the crucible, there is a cooling element in the form of a cooling duct extending along the length of the crucible for receiving the cooling fluid. Forced cooling of the crucible when the heating element is switched off enables the crucible to be cooled more quickly so that the supply of a feed gas can be terminated sooner. This is important if an ion source is being switched from one feed gas to another. Also, the crucible may be forced cooled simultaneously while energizing the heating element to enable the crucible to be accurately controlled at a lower operating temperature if desired.

Abstract: This invention relates to a method of producing a dopant gas species containing a required dopant element for implanting in a target and to an ion source for implementing such a method. In particular, although not exclusively, this invention relates to producing dopant ions for implanting in semiconductor wafers using an ion implanter. The present invention provides a method of producing a dopant gas species containing a required dopant element for implanting in a target, the method comprising: exposing a source mass of the element to gaseous bromine and element react to form a reactant product, and ionising the reactant product to produce ions of the dopant gas species.

Abstract: Dose uniformity of a scanning ion implanter is determined. A base beam current is measured at the beginning and/or the end of a complete scan over the whole substrate area. This base beam current is measured at a time when the measurement should be unaffected by outgassing from a substrate being implanted and a base dose distribution map is then calculated for the scan in question. During the scan itself beam instability events are detected and the magnitude and position in the scan of the detected instability events is measured. Corresponding deviations in the calculated base dose map are determined and subtracted from the previously calculated base dose distribution map to provide a corrected distribution map. By determining overall dose uniformity substractively in this way, good overall accuracy can be obtained with lesser accuracy in the measurement of the beam instability events.

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 vapor. The vapor 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 ion implanter incorporates an r.f. accelerator assembly to provide ions for implant at high energies. The accelerator assembly includes electrodes mounted in the vacuum chamber so as to be movable between an operational position for generating and accelerating electric field and a non operational position within the vacuum chamber displaced clear of the beam path. An Actuator moves the electrode between the operational and non operation positions. For energy implanting, the electrodes are in the operational position and for low energy implants the actuator moves the electrodes to the non operational position clear of the beam path.

Abstract: An ion implanter has an ion source (10) and an ion beam extraction assembly (50) for extracting the ions. The extraction assembly (50) is a tetrode structure and one of the pairs of extraction electrodes (51) has left and right ports (54, 55) located in opposite sides of the ion beam emerging from the ion source (10). The left and right electrode ports (54, 55) are electrically isolated from each other and connected to independent voltage sources (210, 230). The ion implanter also has a baffle plate (60) at the entrance to a mass analyser (90) downstream of the extraction assembly (50). The baffle plate (60) is also split into two halves (60? and 60?). By measuring the beam current incident on the two halves (60?, 60?) of the baffle (60), the relative voltages supplied to the left and right electrode parts (54, 55) may be adjusted so as to steer the ion beam and adjust the angle of incidence of the longitudinal axis thereof relative to the input of the analysing magnet (90).

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: A force compensator is provided for a semiconductor processing apparatus having a moving member, in order to compensate for a fixed force on the moving member, such as gravity or atmospheric pressure. A vacuum and piston combination is connected between the movable member and a reaction point. One side of the piston is open to atmosphere and the other side defines an enclosed region which is evacuated. The cylinder is evacuated to a pressure which does not exceed 10% of ambient pressure during operation of the device, so that pressure changes in the low pressure region have minimal effect on the compensation force during movement of the movable member over its displacement range.

Abstract: A method is provided for uniformly implanting a wafer with an ion beam. The wafer is generally of the type with a surface area in the form of a disk with a diameter and center. The ion beam is first formed as an elongated shape incident on the wafer, the shape having a length along a first axis smaller than the diameter, and a width shorter than the length along a second axis. Next, the wafer is translated at a variable translational velocity in a direction substantially parallel with the second axis. The wafer is also rotated substantially about the center at a rotational velocity. These movements are made such that the ion beam implants the wafer with substantially uniform dose across the surface area of the wafer. The wafer is preferably translated such that the ion beam implants the wafer from one side of the wafer, across the surface area of the wafer, and through another side of the wafer, in a selected velocity versus position profile.

Abstract: The invention relates to an ion source for an ion implanter in which source material for providing desired ions is provided in the form of a plate or liner which can be fitted into the reactant chamber of the ion source.

Abstract: G2 electrode is mounted so as to be movable along the beam line and, optionally, perpendicular to it as well. G1 and G2 are curved with a constant gap between G1 and G2 in the radial direction (so that the two electrodes are concentric). This contrasts with the prior art where G1 and G2 were equidistantly spaced along the beam line direction instead. G1 is made re-entrant adjacent the slit so as to improve extraction efficiency from the plasma. Finally, a lens such as a quadrupole lens is formed downstream of G3.

Abstract: An apparatus for processing wafers one at a time. The apparatus has a vacuum chamber into which wafers are loaded through a pair of loadlocks which are spaced one above the other. A robot within the vacuum chamber has a pair of gripper arms which are moveable along and rotatable about a vertical axis so as to be moveable between the loadlocks and a wafer processing position. Each of the loadlocks has a vertically moveable portion which is moveable away from the remainder of the loadlock to provide access in a horizontal plane for one of the gripper arms. Signals from encoders and optical sensors are used to determine that a handoff position has been reached.

Abstract: The invention relates to an ion source for an ion implanter in which source material for providing desired ions is provided in the form of a plate or liner which can be fitted into the reactant chamber of the ion source.

Abstract: An electrically insulating vacuum coupling for use in an ion implanter for connecting any two parts of the vacuum chamber housing together while maintaining the electrical potentials of the two parts. The coupling comprises an inner sleeve of ceramic material (e.g. Al2O3) and an outer sleeve of a polymer/litharge mixture. The polymer may be a urethane polymer. Litharge is included in the material of the outer sleeve to absorb x-rays produced within the vacuum chamber.

Abstract: An apparatus for processing wafers one at a time. The apparatus has a vacuum chamber 1 into which wafers are loaded through a pair of loadlocks 3, 4 which are spaced one above the other. A robot within the vacuum chamber 1 has a pair of gripper arms 22, 29 which are moveable along and rotatable about a vertical axis 23 so as to be moveable between the loadlocks 3, 4 and a wafer processing position. Each of the loadlocks 3, 4 has a vertically moveable portion 8, 26 which is moveable away from the remainder of the loadlock to provide access in a horizontal plane for one of the gripper arms 22, 29.

Abstract: A scan wheel for an ion implanter. The scan wheel having a plurality of wafer support elements each having an elastomer layer 7 on which a wafer is supported. Each wafer support element 3 has a plurality of spring loaded plungers 10 of a material having a lower coefficient of friction than that of the elastomer layer 7 so as to support a wafer such that it can be slid across the wafer support element 3 without sticking to the elastomer layer 7. A position detector 33 can be provided on a gripper which mounts each wafer on a wafer support element to detect that the wafer has been correctly positioned.

Abstract: A method is provided for uniformly implanting a wafer with an ion beam. The wafer is generally of the type with a surface area in the form of a disk with a diameter and center. The ion beam is first formed as an elongated shape incident on the wafer, the shape having a length along a first axis smaller than the diameter, and a width shorter than the length along a second axis. Next, the wafer is translated at a variable translational velocity in a direction substantially parallel with the second axis. The wafer is also rotated substantially about the center at a rotational velocity. These movements are made such that the ion beam implants the wafer with substantially uniform dose across the surface area of the wafer. The wafer is preferably translated such that the ion beam implants the wafer from one side of the wafer, across the surface area of the wafer, and through another side of the wafer, in a selected velocity versus position profile.