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Showing papers by "Varian Associates published in 1983"


Patent
22 Aug 1983
TL;DR: In this article, a direct contact microwave hyperthermia applicator includes a plurality of rectangular waveguide sections each having a radiating aperture, mounted with their long sides abutting.
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.

180 citations


Patent
19 Jul 1983
TL;DR: In this article, a system for handling and individually processing a plurality of thin substrates is described, which includes a main chamber, entrance and exit load locks, a multiplicity of processing stations, a load lock load/unload means, a vertical transport means, and a horizontal transport means.
Abstract: A system for handling and individually processing a plurality of thin substrates is described The system includes a main chamber, entrance and exit load locks, a plurality of processing stations, a load lock load/unload means, a vertical transport means, and a horizontal transport means In one embodiment the processing stations are deployed in a U-shaped configuration, allowing the entrance and exit load locks to be positioned at the same end of the machine Idle stations between processing stations may also be employed The substrates are vertically oriented and are raised and lowered into and out of load locks and processing stations by means of dedicated lift blades Substrates are transferred within the main chamber from lift blades of one station to lift blades of an adjacent station by means of substrate carriers affixed to a walking beam mechanism Substrates are transferred from the entrance load lock side of the machine to the exit load lock side by means of a reversing mechanism, which may be a rotating beam mechanism, or which may be a transverse motion mechanism which affects a rotationless substrate transfer A lift blade symmetrically engages a substrate nearer the lower half of its periphery, holding the substrate securely with the aid of gravity, and negligibly obscuring or eclipsing either surface of the substrate The lift blades carry the substrates into the processing stations and hold them in place during processing, or simultaneous processing of both sides of the substrates may be carried out

80 citations


Journal ArticleDOI
TL;DR: Magnesium-doped GaAs has been grown by organometallic vapor phase epitaxy (OM-VPE) as discussed by the authors, and the material is of high electrical and optical quality; controllable doping over the range 1015 to 1019cm-3 is reproducibly attained.
Abstract: Magnesium-doped GaAs has been grown by organometallic vapor phase epitaxy (OM-VPE). Bis (cyclopentadienyl) mag-nesium (Cp2Mg) is used as the organometallic precursor to Mg. The epitaxial layers have been characterized by resis-tivity and Hall measurements, photoluminescence spectro-scopy and optical microscopy. The material is of high electrical and optical quality; controllable doping over the range 1015 to 1019cm-3 is reproducibly attained. The ionization energy of the Mg acceptor is determined to be 30 ± 2.5 meV at 77K. Negligible compensation is observed, consistent with clean thermolysis of the Cp2Mg under growth conditions. GaAs diodes have been fabricated using Mg as the p-dopant and either Se, Si, or Sn as the n-dopant. The diodes show very low leakage currents under reverse bias, even at relatively high doping levels. Degenerately-doped junctions for interconnecting monolithic cascade concentrator solar cells have also been successfully grown, displaying forward conductivities as high as 19 amps V−1 cm-2 at 0.05V forward bias.

80 citations


Patent
27 Dec 1983
TL;DR: The magnetic field of a magnetron sputter coating apparatus is controlled in response to measurements of plasma parameters to control deposition parameters, such as sputter deposition rate and material deposition thickness profile as mentioned in this paper.
Abstract: The magnetic field of a magnetron sputter coating apparatus is controlled in response to measurements of plasma parameters to control deposition parameters, such as sputter deposition rate and material deposition thickness profile. From time to time the apparatus is standardized to change preset values for parameters of the plasma to manage the deposition parameters.

61 citations


Journal ArticleDOI
TL;DR: In this paper, the operation of a millimeter-wave harmonic gyrotron is described in which the interaction is between large-orbit axis-encircling electrons and cylindrical cavity TEnll modes.
Abstract: The operation of a millimeter-wave harmonic gyrotron is described in which the interaction is between large-orbit axis-encircling electrons and cylindrical cavity TEnll modes. Efficiencies up to 15% have been measured for moderate harmonic interactions and multi-kW power levels have been attained at the tenth harmonic of the cyclotron frequency. The concept allows the magnetic field of the gyrotron to be reduced by an order of magnitude, thereby making a submillimeter-wave gyrotron feasible.

57 citations


Patent
09 Jun 1983
TL;DR: In this paper, a thermal transfer gas is used to transfer thermal energy between a semiconductor wafer and a platen during processing in a vacuum chamber, and 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: 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.

47 citations


Patent
08 Sep 1983
TL;DR: In this article, 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, which includes an internal processing zone (32) in which the requisite processing level vacuum is maintained.
Abstract: @ An envelope apparatus is provided for facilitating the production of a vacuum at a localized region on the surface (30) 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 (32) in which the requisite processing level vacuum is maintained. The envelope apparatus also includes intermediate vacuum zones (34) 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. The envelope apparatus is held either in a fixed position with respect to the surface of the article or actively tracks the topography of the surface of the article so that the gap between the external surface and the surface of the article lies within an acceptable range. For semiconductor processing applications, it has been found that a graded seal formed by two-stage differential pumping and having a gap in the range of 20 micrometers to 40 micrometers will permit vacuums on the order of 10.5 Torr to be maintained within the interior processing zone of the envelope apparatus.

45 citations


Patent
27 Dec 1983
TL;DR: In this article, a magnetron sputter coating source is described, in which magnetic sputter targets containing relatively large inventories of usable material may be employed, and the use of a Hall probe positioned adjacent and below the sputter target near the region of maximum erosion is disclosed.
Abstract: A novel magnetron sputter coating source is disclosed in which magnetic sputter targets containing relatively large inventories of usable material may be employed. This coating source may also be used efficiently and effectively with sputter target materials having properties which range from nonmagnetic to highly ferromagnetic. Use of an electromagnetic coil with a widely adjustable energizing current, rather than permanent magnets, allows a wide range of magnetic properties to be accommodated. Electrical impedance of the glow discharge is readily controlled using the current flow through the electromagnetic coil, allowing, for example, operation at desired values of voltage and current throughout the life of the sputter target. In addition, a momentary increase in electromagnet coil current can be used to achieve ignition of the glow discharge at a desired sputter gas operating pressure which is below the sputter gas pressure at which the glow discharge can normally be readily ignited. Also, use of the electromagnetic coil permits an easy conversion of the magnetron sputter coating source to a nonmagnetic diode apparatus. The use of a Hall probe positioned adjacent and below the sputter target near the region of maximum erosion is disclosed. The Hall probe voltage, which is proportional to the magnetic field intensity at the Hall probe position, may be measured throughout sputter target life to provide an independent means of assessing the approach to end of useful life. A novel sputter target cooling means is disclosed in which a water chamber below the sputter target is divided into inlet and outlet portions by a septum. The flow of water through a narrow gap between the septum and the sputter target leads to highly effective heat transfer, which is also highly uniform along the peripheral path of intense heating of the sputter target.

44 citations


PatentDOI
TL;DR: A direct contact hyperthermia applicator includes an ultrasonic lens with an arrays of ultrasonic transducers and an array of microwave antenna elements mounted behind the lens and positioned for transmission of ultrasonic wave energy and microwave energy therethrough.
Abstract: A direct contact hyperthermia applicator includes an ultrasonic lens with an array of ultrasonic transducers and an array of microwave antenna elements mounted behind the lens and positioned for transmission of ultrasonic wave energy and microwave energy therethrough. The antenna elements can be waveguide sections having radiating apertures or microstrip antenna elements. A fluid enclosure is defined between the front surface of the lens and a thin rubber sheet sealed around the periphery of the lens. During hyperthermia treatment, the rubber sheet conforms to the contours of the patient's body. The fluid, which is typically cooled distilled water, improves coupling of microwave energy and ultrasonic wave energy into the patient's body and cools the surface region.

42 citations


Journal ArticleDOI
Frank J. Yang1

39 citations



Patent
08 Sep 1983
TL;DR: In this article, the gap between localized vacuum processing envelope apparatus and a semiconductor wafer is measured by a gap sensor and an actuating means for varying the gap in response to the error signal.
Abstract: Apparatus for controlling the gap between localized vacuum processing envelope apparatus and a workpiece as the workpiece, typically a semiconductor wafer, is moved laterally with respect to the envelope apparatus. The envelope apparatus includes an envelope which defines an internal vacuum processing zone and a generally planar tip spaced from the workpiece during processing by the gap. The gap control apparatus includes a gap sensor for measuring the gap, a control circuit for comparing the measured gap with a required gap and generating an error signal, and an actuating means for varying the gap in response to the error signal. The gap can be sensed by sensing the pressure level in the vacuum processing apparatus. The actuating means can include a plurality of piezoelectric actuators which can vary both the gap and the angle of the workpiece with respect to the tip of the vacuum processing apparatus. The disclosed apparatus is particularly useful in connection with particle beam systems such as electron beam lithography systems. In another embodiment, the gap is controlled by an air bearing between the envelope apparatus and the workpiece.

Patent
21 Jan 1983
TL;DR: In this article, a heater assembly for annealing a semiconductor wafer in a vacuum chamber includes a blackbody source having a constant planar energy flux charactertistic and a wafer support for supporting the wafer adjacent to, but not spaced apart from, the source in planar parallel alignment therewith.
Abstract: A heater assembly for annealing a semiconductor wafer in a vacuum chamber includes a blackbody source having a constant planar energy flux charactertistic and a wafer support for supporting the wafer adjacent to, but not spaced apart from, the source in planar parallel alignment therewith. The heater assembly further includes radiation shields and a housing providing support for the source, the wafer support and the radiation shields in fixed relationship. The housing includes a heat sink for removal of thermal energy and a slot for insertion and removal of the wafer. The heater assembly confines thermal energy and reduces input energy requirements. In addition, the requirement for a movable shutter is eliminated.

Patent
02 Nov 1983
TL;DR: In this paper, a substrate having two parallel planar faces and an edge with a groove is simultaneously coated on both sides in a vacuum chamber, and the parallel faces are vertically disposed by a blade inserted into the groove so that while the substrate is coated an unobstructed path exists for the coating material to the faces.
Abstract: A substrate having two parallel planar faces and an edge with a groove is simultaneously coated on both sides in a vacuum chamber. The substrate is raised, lowered and held on edge while the parallel faces are vertically disposed by a blade inserted into the groove so that while the substrate is coated an unobstructed path exists for the coating material to the faces.

Journal ArticleDOI
R.A. Powell1, R. Chow1, C. Thridandam1, R.T. Fulks2, I.A. Blech2, J.-D.T. Pan2 
TL;DR: Titanium silicide thin films, sputter deposited from a composite silicide target, have been rapidly sintered in ∼10 s to produce extremely uniform highly conductive layers (≲ Ω/sq +mn; 1 percent over a 4-in wafer) with film stress comparable to furnace-annealed films as discussed by the authors.
Abstract: Titanium silicide thin films, sputter deposited from a composite silicide target, have been rapidly sintered in ∼10 s to produce extremely uniform highly conductive layers (≲ Ω/sq \plusmn; 1 percent over a 4-in wafer) with film stress comparable to furnace-annealed films. Such films are suitable for VLSI applications. In addition, silicide formation and activation of ion-implanted species in adjacent Si regions can be accomplished in the same rapid processing step without significant dopant redistribution.

Patent
19 Sep 1983
TL;DR: In this paper, an x-y table, a stage assembly movable along the z-axis for holding the wafer, coupled with a plurality of fluid-containing bellows coupled between the 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.
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.

Patent
08 Apr 1983
TL;DR: In this article, an RF probe for a gyromagnetic resonance spectrometer includes a coil cage for supporting the probe coil, which is formed of a number of rod-like members displaced parallel to the coil axis and spaced apart from the axis at a constant distance.
Abstract: An RF probe for a gyromagnetic resonance spectrometer includes a coil cage for supporting the probe coil preferably within the cage formed of a number of rod-like members displaced parallel to the coil axis and spaced apart from the axis at a constant distance. Access to the coil through an axial continuous slot 46 or equivalent eliminates axial discontinuity in susceptibility due to discrete holes in the coil form.

Patent
Albert P. Zens1
07 Apr 1983
TL;DR: In this paper, the magnetic susceptibility of materials can be tailored to achieve a desired value to suppress magnetic perturbation without introducing extraneous signals, where the sample is rotated along an axis transverse to the field.
Abstract: It is desired to promote magnetic homogeneity of materials, including structural elements, present in the sensitive volume of a gyromagnetic analysis apparatus. Where the sample is rotated along an axis transverse to the field the requirement reduces to establishing axial homogeneity. Plugs which match the solvent magnetic susceptibility are employed to constrain a sample within the central region of an RF probe coil thereby appearing relatively invisible in the magnetic sense to the instrument. The susceptibility of materials can be tailored to achieve a desired value to suppress magnetic perturbation without introducing extraneous signals.

Patent
28 Jul 1983
TL;DR: 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 as discussed by the authors.
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.

Patent
23 May 1983
TL;DR: In this article, a rotatable vacuum chuck is used to rotate a semiconductor wafer in an ion implantation system so as to limit channeling and to control the depth of penetration of impinging ions.
Abstract: Apparatus for programmably orienting a semiconductor wafer (122) in an ion implantation system so as to limit channeling and to control the depth of penetration of impinging ions. The apparatus is associated with a processing chamber door (134) and includes a rotatable vacuum chuck (138) for engaging the wafer (122) and a motor (142) for rotating the vacuum chuck (138) and the wafer (122) through a preselected angular displacement. The apparatus further includes a programmable control assembly (144) operative to deenergize the motor (142) upon sensing rotation of the vacuum chuck (138) through the preselected angular displacement. The wafer orientation apparatus is typically utilized in a system for the vertical transfer of wafers between a cassette and a processing chamber (114).

Patent
12 Oct 1983
TL;DR: In this paper, 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.
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 coupled between the ridges and the fingers and the phase or amplitude of the signals is detected. An aligner utilizing multiple groups of ridges and fingers allows rotational alignment or two axis lateral alignment. An aligner having reference ledges to which the mask and the wafer are capacitively coupled allows alignment when the distance between the mask and the wafer is too great to permit meaningful capacitive coupling between the mask and the wafer to occur.

Journal ArticleDOI
TL;DR: A selective oxidation of thioridazine to give exclusively its ring sulfoxides and a separation of the resulting products as diastereoisomeric pairs of enantiomers (DL, LD and DD, LL) are reported.

Journal ArticleDOI
Steve Bandy1, Y.G. Chai, R. Chow, C.K. Nishimoto, G. Zdasiuk 
TL;DR: In this article, the reduction in gate metallization resistance and improvement in performance of submicron-gate GaAs FET's has been achieved by employing a mushroom profile defined by electron-beam exposure.
Abstract: The substantial reduction in gate metallization resistance and improvement in performance of submicron-gate GaAs FET's has been achieved by employing a mushroom profile defined by electron-beam exposure. Using MBE growth of buffer, channel, and n+ contact layers, minimum noise figures of 1.0-1.1 dB have been demonstrated at 8 GHz, with associated gains of 13-14 dB.

Patent
23 May 1983
TL;DR: In this paper, a photo sensor is used to detect the presence of a missing or broken wafer at a second position along a prescribed path and inhibits the counter, and the count stored in the counter is compared with a predetermined count corresponding to the time required for movement of an unbroken wafer to the second position.
Abstract: Apparatus for sensing a missing or broken wafer in an automated wafer transfer system. The apparatus includes means for moving a wafer transfer mechanism from a first position along a prescribed path. A counter coupled to an oscillator is enabled when the wafer transfer mechanism and a wafer are moved away from the first position. A photosensor senses the presence of the wafer at a second position along the prescribed path and inhibits the counter. The count stored in the counter is compared with a predetermined count corresponding to the time required for movement of an unbroken wafer to the second position. If the counts do not agree, a missing or broken wafer is indicated and corrective action is taken.

Patent
23 May 1983
TL;DR: In this paper, the authors present an apparatus for displaying a plurality of remotely measured parameters, which 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.
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.

Patent
09 Jun 1983
TL;DR: In this article, a system for imaging P-31 spectra from different slices through a living body specimen positioned in the bore of the hollow main field magnet of an NMR spectrometer is presented.
Abstract: A system for imaging P-31 spectra from different slices through a living body specimen positioned in the bore of the hollow main field magnet of an NMR spectrometer, consisting of applying a timed series of different discrete different-amplitude magnetic field gradient pulses to the specimen, whereby to generate time-spaced echo signals from respective points along the specimen while timed RF resonance excitation pulses are applied to the specimen. The echo signals are used to derive respective chemical shift spectra from the points, each spectrum containing information showing the in vivo metabolic state at one of the points. The various spectra can be simultaneously displayed to enable concurrent slice-by-slice interpretation of the metabolic information. The gradient pulses are derived from coils mounted inside the main field magnet arranged to generate a magnetic field vector traversing the specimen. The gradient coils are energized by using a suitably programmed computer. The gradient current pulses are applied concurrently with the RF excitation pulses.

Patent
Frank J. Yang1
21 Apr 1983
TL;DR: In this article, a plume is moved out of seated engagement within a cavity to permit a jet stream of mobile phase fluid to sweep the sample from the sample groove out through the outlet end of the cavity and onto a chromatographic column connected to the injector housing.
Abstract: A plunger seats in the outlet end of a cavity formed in an injector housing. The plunger is moveable within the cavity between seated engagement with the outlet end and a position which permits fluid to flow out the outlet end. The cavity is sealed to withstand pressures on the order of 2000 bar. A groove formed in the wall of the plunger or in the wall of the cavity receives liquid sample from a sample feed line which is formed in the body of the housing and terminates adjacent the groove when the plunger is seated in the outlet end of the cavity. A source of mobile phase fluid is connected to the upper end of the cavity by an inlet line. By external displacement means, the plunger is moved out of seated engagement within said cavity to permit a jet stream of mobile phase fluid to sweep the sample from the sample groove out through the outlet end of the cavity and onto a chromatographic column connected to the injector housing.

Patent
27 Jul 1983
TL;DR: In this article, a calorimetric load for very high microwave power at very high frequencies is formed by a metallic, cylindrical chamber into which the waveguide carrying the power opens.
Abstract: A calorimetric load for very high microwave power at very high frequencies is formed by a metallic, cylindrical chamber into which the wave-guide carrying the power opens. Inside the metallic cylinder is a coaxial dielectric cylinder, with a space between full of circulating wave-absorbing fluid such as water. The incoming wave may be in a higher-order mode. To make it disperse rapidly into the absorbing fluid, a conical reflector is located inside the dielectric cylinder to reflect the wave outward.

Journal ArticleDOI
Eiji Tanabe1
TL;DR: In this paper, a multiple-use cavity test system was developed to establish the criteria for voltage breakdown in S-band pulsed electron linear accelerator cavities, in terms of cavity geometry, accelerating gradient, RF pulse shape and repetition rate, surface finish, temperature and external magnetic field.
Abstract: Voltage breakdown is one of the major limiting factors in the design of a high accelerating gradient linear accelerator structure. A multiple-use cavity test system was developed to establish the criteria for voltage breakdown in S-band pulsed electron linear accelerator cavities, in terms of cavity geometry, accelerating gradient, RF pulse shape and repetition rate, surface finish, temperature and external magnetic field. The experimental set-up and test procedure, as well as the experimental results, are presented.

Patent
19 Aug 1983
TL;DR: In this paper, a method of sputter depositing a desired film thickness profile on a substrate is accomplished by depositing material onto a substrate at spaced apart coating stations whereby a substrate from any of said stations is not coated by the sputter coating action at any of the other sputter stations.
Abstract: A method of sputter depositing a desired film thickness profile on a substrate is accomplished by depositing material onto a substrate at spaced apart coating stations whereby a substrate at any of said stations is not coated by the sputter coating action at any of the other sputter stations. The substrate is held stationary during complete sputtering at each station. A blocking shield is placed in fixed position between the substrate and the sputter coating source at one or more of the stations. The duration of sputter coating time at one station may be different than at another station.