Abstract: A vacuum pick suitable for removing semiconductor wafers from and replacing wafers in a cassette holder. The vacuum pick includes a thin profile housing having a wafer support surface with a cavity therein, a resilient, flexible member covering a portion of the cavity to form an enclosure, and a rigid chuck mounted on the flexible member so as to permit movement of the chuck relative to the housing. The chuck includes a wafer-receiving surface connected through a passage to the enclosure. When a vacuum is applied to the enclosure, the wafer and the chuck are retracted against the housing and held firmly in place. The chuck tilts relative to the housing when it contacts a tilted wafer, thereby insuring reliable attachment to the wafer.

Abstract: An X-ray lithography apparatus permits the successive exposure of each of four quadrants of a semiconductor wafer through a single mask. The mask overlays one quadrant of the wafer at a time and the wafer is rotated through 90 degrees after exposure of a quadrant to allow exposure of succeeding wafer quadrants; each wafer quadrant is independently aligned to the mask prior to exposure. In an alternative preferred embodiment, a rotatable diaphragm is used to select a single mask quadrant from a mask which overlays the entire surface of the semiconductor wafer. Both the wafer and the diaphragm may be rotated to allow various exposure combinations of mask and wafer quadrants.

Abstract: A Freeman type electron bombardment ion source includes dual filament electrodes positioned in an arc chamber having a slit for extraction of an ion beam. The filament electrodes are symmetrically positioned with respect to the extraction slit. The filament electrode currents are equal in magnitude and oppositely directed. As a result, lateral magnetic fields in the region of the extraction slit are substantially eliminated.

Abstract: An aligner for aligning a mask and a wafer during photolithography of a semiconductor chip uses detection of the differential capacitance between two sets of conductive fingers on the mask and ridges on the wafer. An A.C. signal is applied to the ridges and the phase or amplitude of the signals coupled to the two sets of fingers is detected and compared. A shield is positioned between the ridges and the fingers to ensure that coupling occurs only between desired portions of the ridges and the fingers.

Abstract: A charged particle beam lithography machine includes a beam source and beam steering and forming elements within an evacuated column. A stage assembly for supporting a semiconductor wafer or mask is positioned in ambient and proximate the exit end of said beam steering and forming elements. A vacuum envelope apparatus is affixed to the exit end of the beam steering and forming elements so that the outer surface or tip of the vacuum envelope apparatus rests in spaced apart, close coupled opposition to the wafer or mask supported on the stage. The vacuum envelope apparatus includes internal structural members which define an internal vacuum processing zone and at least one surrounding intermediate vacuum zone. A graded vacuum seal is formed between the tip of the vacuum envelope and the mask or wafer. The seal extends from the internal vacuum processing zone to the external ambient.

Abstract: A multiple wafer holder generally of the size and shape of a standard wafer has on its front surface a plurality of pockets. The edge of each pocket is generally V-shaped and grooved so that wafers of different sizes can be carried by each holder and more than one wafer can be transported together into the processing chamber of an implanter from a cassette.

Abstract: Provided is an apparatus for improving alignment accuracy by distorting in a controlled manner an X-ray lithographic mask to compensate for mask distortions induced primarily by thermally induced clamping effects in E-beam and X-ray exposure systems. A system of additional alignment sensors is used to provide localized misalignment information. This information is then used to provide feedback to a servo system which in turn activates electromechanically translatable clamps which distort the X-ray mask so as to minimize misalignment over the exposure field.

Abstract: A direct contact microwave hyperthermia applicator includes a plurality of rectangular waveguide sections each having a radiating aperture. The waveguide sections are mounted with their long sides abutting. A pair of shutter elements for individually varying the radiating aperture is associated with each of the waveguide sections. The shutters can be adjusted to form a desired composite aperture which produces a radiation pattern adapted for efficient hyperthermia treatment of a tumor having a prescribed size, shape and location. Microwave power supplied to the radiating elements can be varied in phase and power level to further control the radiation pattern.

Abstract: A coaxial magnetron has a high-Q resonant cavity surrounding a multiple-resonator anode circuit and coupled by slots to alternate anode resonators. The cavity is resonant in the TE.sub.111 mode, having two zero points of electric field on its periphery. The anode circuit is correspondingly resonant in its N/2-1 mode.Mode suppression means damp out the degenerate TE.sub.111 mode which is not coupled to the output iris.The size and weight of the magnetron are much less than conventional tubes using a cavity resonant in the TE.sub.011 mode with circular electric field.

Abstract: An envelope apparatus is provided for facilitating the production of a vacuum at a localized region on the surface of an article such as a semiconductor wafer. The vacuum permits vacuum processing in the localized region. The envelope apparatus includes an internal processing zone in which the requisite processing level vacuum is maintained. The envelope apparatus also includes intermediate vacuum zones surrounding the internal processing zone. The internal processing zone and surrounding intermediate vacuum zones are exposed at an external surface so that when the external surface is placed in spaced apart, close coupled opposition to the article being processed a graded vacuum seal is formed. The graded seal extends from the internal processing zone, past the intermediate vacuum zones and out to ambient.

Abstract: Apparatus for displaying a plurality of remotely measured parameters. The data words representing the parameters have different scale factors and include a parameter identifier and a parameter value. The apparatus includes a decoder for determining from the parameter identifier the scale factor associated with a data word and a scaling circuit for scaling the parameter value. The scaling circuit can include binary dividers, one of which is selected by the decoder output. The scaled parameter value addresses a ROM which provides BCD digits for energizing a display unit associated with the parameter.

Abstract: An rf multiplexer includes a plurality of rf switch assemblies for switching a selected rf signal to an output in response to an optical control signal. Each rf switch assembly includes a switch circuit mounted in a conductive enclosure. The optical control signal from a control circuit is coupled by an optical fiber into the enclosure to an optical receiver which energizes a diode rf switch. Spurious conduction of rf signals along switch control lines is thereby eliminated without using filters. The multiplexer is particularly useful in a direct frequency synthesizer requiring high speed switching.

Abstract: Apparatus for providing thermal transfer between a semiconductor wafer and a heat sink or source in a vacuum processing chamber includes a platen against which the wafer is sealed to define a thermal transfer region therebetween. The platen includes a passage for gas flow between the chamber and the thermal transfer region. The apparatus further includes a valve for controllably opening and closing the passage and a controller for closing the valve when the pressure in the chamber reaches a predetermined value. Gas at the predetermined pressure, typically 0.5 to 100 Torr, is trapped in the thermal transfer region and conducts thermal energy between the workpiece and the platen. In a preferred embodiment, a plurality of platens are positioned on a rotating disc in an ion implantation system and a centrifugally operated valve is utilized to close the passage.

Abstract: Apparatus for positioning a semiconductor wafer with respect to a localized vacuum envelope so as to maintain a prescribed gap between the tip of the vacuum envelope and the wafer includes an x-y table, a stage assembly movable along the z-axis for holding the wafer and a z-axis actuator assembly. The z-axis actuator assembly includes a plurality of fluid-containing bellows coupled between the x-y table and the stage assembly and a hydraulic controller operated by a linear stepper motor for varying the fluid volume in each of the bellows in response to an actuator control signal so as to move the stage assembly along the z-axis. The z-axis actuator assembly can further include a flexible disk positioned in the plane of x-y movement and coupled between the x-y table and the stage assembly for preventing lateral and rotational movement of the stage assembly relative to the x-y table. The positioning apparatus is suitable for use in an electron beam lithography system.

Abstract: A magnetic lens for imaging and rotation of a charged particle beam includes a pair of focus elements axially spaced along a lens bore through which the beam passes and a rotation element positioned axially between the focus elements. Each of the lens elements includes a polepiece having opposing portions surrounding the lens bore and axially spaced apart to define a circumferential gap, and a winding for energizing the polepiece and the gap. The focus elements are energized by equal and opposite magnetic fields which focus the electron beam without substantial beam rotation. The beam can be rotated, without substantial change in focus or magnification, by varying the magnetic field of the rotation element. The lens is particularly suited for use in a shaped electron beam lithography system.

Abstract: Methods and apparatus for differential pumping of a thermal transfer gas used to transfer thermal energy between a semiconductor wafer and a platen during processing in a vacuum chamber. Housing structure defines an intermediate region adjacent to and surrounding the platen. The gas, which is introduced into a thermal transfer region behind the wafer, is restricted from flowing into the intermediate region by intimate contact between the wafer and the platen. A clamping ring, which clamps the wafer to the platen, and a bellows coupled between the clamping ring and the housing restrict flow of gas from the intermediate region to the vacuum chamber. The intermediate region is vacuum pumped to a pressure lower than the pressure in the thermal transfer region whereby leakage of the gas into the vacuum chamber is reduced.

Abstract: Conductive heat transfer between a thin deformable workpiece and heat sink is optimized by imposing a load over the workpiece resulting in a uniform contact pressure distribution in said workpiece which is also the maximum stress consistent with the elastic properties of the workpiece. The surface of the heat sink is given a contour determined by these criteria for a thin circular disk clamped thereto.

Abstract: Conductive heat transfer between a thin deformable workpiece and heat sink is optimized by imposing a load over the workpiece resulting in a uniform contact pressure distribution in said workpiece which is also the maximum stress consistent with the elastic properties of the workpiece. The surface of the heat sink is given a contour determined by these criteria for a thin circular disk clamped thereto.

Abstract: Apparatus for providing thermal transfer between a semiconductor wafer and a heat sink or source in a vacuum processing chamber includes a platen against which the wafer is sealed to define a thermal transfer region therebetween. The platen includes a passage for gas flow between the chamber and the thermal transfer region. The apparatus further includes a valve for controllably opening and closing the passage and a controller for closing the valve when the pressure in the chamber reaches a predetermined value. Gas at the predetermined pressure, typically 0.5 to 100 Torr, is trapped in the thermal transfer region and conducts thermal energy between the workpiece and the platen. In a preferred embodiment, a plurality of platens are positioned on a rotating disc in an ion implantation system and a centrifugally operated valve is utilized to close the passage.

Abstract: Apparatus for providing thermal transfer between a semiconductor wafer and a heat sink or source in a vacuum processing chamber includes a platen against which the wafer is sealed to define a thermal transfer region therebetween. The platen includes a passage for gas flow between the chamber and the thermal transfer region and a conduit for circulation of a cooling fluid. The platen further includes a fluid-actuated valve responsive to the pressure of the cooling fluid for closing the passage. When the pressure in the chamber reaches a predetermined value, the cooling fluid is turned on and closes the valve. Gas at the predetermined pressure, typically in the range of 0.5 to 100 Torr, is trapped in the thermal transfer region and conducts thermal energy. In a preferred embodiment, a plurality of platens are positioned on a rotating disc in an ion implantation system.