Showing papers by "Varian Associates published in 1986"

Sputter module for modular wafer processing system

Abstract: A machine for sputter deposition of a wafer workpiece also sputters on the wafer supporting mechanism. This causes a need for cleaning or replacement of the support mechanism. A sputter machine is provided in which the supporting mechanism can be isolated from the sputtering source, the pumps and other processing apparatus for cleaning without exposing the entire machine to atmosphere.

Wafer processing system

Abstract: A wafer processing system including wafer handling arms incorporated into vacuum isolation valves is described. A loadlock with elevator and optical sensors is used to inventory and position a cassette of wafers. The wafers in the cassette can be randomly accessed. A computer is used to control the system according to a task status table independent of time sequence.

Compressional wave hyperthermia treating method and apparatus

Abstract: A wide bandwidth compressional wave transducer array obtains information concerning tissue of a subject being treated and supplies hyperthermia compressional wave treating energy to a treated region of the subject. The array transducers are pulsed on and off with an on duty cycle portion of less than one. An array of compressional wave imaging transducers is in the center of the array of compressional wave hyperthermia focused far field transducers used to analyze and treat. The power and duty cycle of the compressional wave hyperthermia focused far field are varied to control the energy incident on certain regions in a treated subject. The ultrasonic frequencies of hyperthermia beams derived from individual transducers are randomly angle modulated so the energy of adjacent far field focused beams overlaps to a greater extent than focused coherent beams.

Wafer processing chuck using slanted clamping pins

Abstract: A wafer is introduced into a processing chamber on a transport device. Lifting pins receive the wafer from the transport device and lower the wafer to the surface of a chuck. Clamping pins lower and hold the wafer by means of enlargements on the ends of the clamping pins. Grooves on the surface of the chuck and internal channels in the chuck are used to supply gas to the back of the wafer for temperature control.

Apparatus and method for manufacturing planarized aluminum films

Abstract: An apparatus for planarizing an aluminum layer on a semiconductor wafer includes two deposition sources. The first source applies a refractory metal silicide layer to form a barrier to oxygen. The wafer is moved to a second deposition source which is an aluminum sputter device including a heater for the wafer, R.F. bias on the wafer and a magnetic mirror behind the wafer to move the plasma away from the wafer.

Valve incorporating wafer handling arm

Abstract: A valve for a wafer processing machine is formed with a wedge-shaped sliding gate. A folded wafer handling arm is stored within the wedge and pumped to keep the arm clean while the valve is closed.

Semiconductor etching apparatus with magnetic array and vertical shield

Abstract: In an apparatus for etching a large semiconductor wafer the etch rate and uniformity of etching at the edges is improved by using an array of magnets behind the collector plate to form a double ring of plasma and using a grounded shield ring with perforations to pass gases. The shield ring extends both above and below the surface of the wafer being etched.

Gate valve for wafer processing system

Abstract: A modular wafer processing system requires a gate valve of minimum thickness. A gate valve is provided in which the gate is an assymetric wedge on an assymetrically mounted drive shaft.

Sputter coating source having plural target rings

Abstract: A sputter coating source has separate annular targets spaced outwardly from each other around a central axis. Magnetic field generating means are provided to establish magnetic field lines over each target around an annular path. Each target has its own separate magnetic field generating means including an electromagnet having a separately controllable power supply whereby the strength of the magnetic field over each target may be separately controlled. The targets are electrically separated from each other, and each target has a separately controllable power supply whereby the plasma power for each target may be separately controlled. More than two separate targets may be employed, and the various targets may be positioned at different distances from the substrate. The targets may be made of magnetic material.

Diffusion bonded x-ray target

Abstract: A rotatable x-ray target assembly and process for manufacturing the same is provided for an x-ray tube. The x-ray target assembly comprises an x-ray target member having an opening disposed therethrough and a support member having: a mounting surface disposed transversely to the axis of rotation, a lower surface of the target member being disposed on the mounting surface; and, a threaded stem extending from said mounting surface through the opening of the target member. The support member also comprises a nut adapted to receive the threaded stem, the nut engaging an upper surface of the target member. The target member is secured to the support member by brazing material disposed between the lower surface of the target member and the mounting surface, a first portion of the brazing material being diffused into the target member and a second portion of the brazing material being diffused into the mounting surface of the support member. With such arrangement, the target member is structurally bonded to the support member. Thus, the target member is substantially prevented from slipping on the support member during the rotation of the x-ray target member during operation of the x-ray tube, thereby preventing the target member from becoming imbalanced on the support member and substantially eliminating vibration of the target member during rotation.

A ladder circuit coupled-cavity TWT at 80-100 GHz

Abstract: The radar, electronic warfare and communications industries will benefit from the recent development of a new family of coupled-cavity traveling wave tubes The new tubes, given the generic name of MILLITRONS can now provide these industries with affordable and available devices for high power millimeter wave transmitters Conventional techniques for manufacturing coupled-cavity traveling wave tubes become impractical for millimeter wave frequencies because of extremely tight tolerances The ladder is a new circuit which eliminates cumulative errors of stacked tubes by a method of simultaneously machining cavities of a circuit The MILLITRON uniquely incorporates ladder technology in the development of millimeter wave devices A recent accomplishment is a 100 W CW coupled-cavity traveling wave tube operating from 80 to 100 GHz

Low compliance seal for gas-enhanced wafer cooling in vacuum

Abstract: Apparatus for thermal transfer with a semiconductor wafer in a vacuum processing chamber includes a platen with a surface for supporting the wafer, a clamping ring for clamping the wafer to the platen, and passages for supplying a low pressure gas into a thermal transfer region between the wafer and the platen surface. A low compliance seal surrounds the thermal transfer region and inhibits the gas from reaching the processing chamber without overstressing the wafer. The seal includes an elastomer ring having an elongated cross-section, and a sealing groove having a first groove portion for gripping one edge of the ring and a second groove portion which receives the other edge of the ring by bending deformation thereof when a wafer is clamped to the platen. In a preferred embodiment, the ring has a parallelogram-shaped cross-section and is oriented at an acute angle to the platen surface.

Magnetron sputter device having separate confining magnetic fields to separate targets and magnetically enhanced r.f. bias

Abstract: A first target for a magnetron sputter device has a planar annular emitting surface bounded by an inner radius R1 and an outer radius R2. A second target has a sloped emitting surface defined by a side wall of a frustum of a cone. The second target is limited by an inner radius R3 and outer radius R4. R3 is greater than R2. Each target element has pins in diametrically opposite holes to assist in holding the target elements in situ in bayonet slots in the sputter device. The targets are fit closely in cooling rings so that as the targets heat during operation, thermal expansion of the targets assists thermal conduction into the cooling rings. A coil is formed behind the workpiece to act as a mirror to the plasma. The field of the coil moves the plasma away from the workpiece which permits putting high power R.F. bias on the workpiece. The R.F. bias in combination with gas heating the wafer from behind aids in sputtering a coating of superior conformality.

Targets for magnetron sputter device having separate confining magnetic fields to separate targets subject to separate discharges

Abstract: A first target for a magnetron sputter device has a planar annular emitting surface bounded by an inner radius R1 and an outer radius R2. A second target has a concave emitting surface defined by a side wall of a frustum of a cone. The second target is limited by an inner radius R3 and outer radius R4. R3 is greater than R2. Each target element has pins in diametrically opposite holes to assist in holding the target elements in situ in bayonet slots in the sputter device. The targets are fit closely in cooling rings so that as the targets heat during operation, thermal expansion of the targets assists thermal conduction into the cooling rings.

Inverted re-entrant magnetron ion source

Abstract: An ion source for an intense ion beam from a solid source is formed with a cathode around a central anode. A source of magnetic field with closely spaced poles is formed around a central region of the cathode so that the most intense region of the magnetic field is a torus on the inside of the cathode and the field at the anode is weak. A torus of plasma can be formed near the inside surface of the cathode which can be coated with solid source material. An ion beam can be extracted through an aperture in the cathode.

Wide bandwidth linear motor system

Abstract: A wide bandwidth linear motor system suitable for high performance applications such as driving the tuning plunger of a magnetron oscillator. The linear motor includes a coil assembly with a structure which suppresses secondary resonances, thereby permitting the linear motor to be used in a wide bandwidth servo control loop. The coil assembly includes a cylindrical coil support, a bushing coaxial with the coil support for attachment to the linear motor shaft, a plurality of radial ribs connecting the coil support to the bushing and a coil having multiple turns wound circumferentially around the coil support. The coil support is subdivided by axial gaps into at least two separate coil support elements, each connected by a radial rib to the bushing. Resonance of the coil support and the coil is suppressed by the separate coil support elements and the lossy connection therebetween.

Double staggered ladder circuit

Abstract: A double-coupled ladder circuit for a traveling-wave tube has been a slow-wave circuit formed of a pair of combs, each cut from a single piece of metal. Transverse grooves are cut in each piece to form teeth and axial grooves are cut in the ends of the teeth. The two combs are joined at teeth ends to form a ladder with the transverse grooves aligned to form cavities and the axial grooves aligned to form a beam passageway. Coupling apertures are cut in both sides of a first set of alternating ladder rungs and a second set of apertures cut in the comb backing members over the second, interleaved, set of rungs. Thus, each cavity is coupled on two opposite sides to its preceding cavity and on the two remaining sides to its following cavity. The double coupling provides increased bandwidth and efficiency. Finally, side plates are affixed to cover the apertures, complete the cavity walls and form the vacuum envelope.

Pulse width modulator for AM-RF transmitter

Abstract: An RF-AM transmitter of the type including a power pulse amplifier driving an RF amplifier with a modulating voltage via a low pass filter includes a pulse width modulator for deriving variable frequency pulses having a frequency that is a direct function of an RMS like function of the amplitude and frequency of an information source; the width of the pulses is determined by the instantaneous amplitude of the information signal source. The pulse width modulator includes a constant amplitude, variable frequency triangular wave voltage controlled oscillator responsive to a DC signal representing the frequency and amplitude of the information source. In response to amplitude crossovers between the variable frequency triangular wave and the information source, transitions in the pulse width modulated wave are derived.

System for measuring the position of a wafer in a cassette

Abstract: In order to compensate for worn or distorted wafer cassettes and missing wafers, the cassette of wafers is scanned through a beam. The timing of the interruptions of the beam is used to inventory the wafers present and measure the exact position of each wafer relative to the base of the cassette.

Method and apparatus for performing an NMR experiment

Abstract: In a method for NMR excitation of a sample, an Rf pulse is applied to an irradiation coil (6) proximate the sample, in the presence of an external DC magnetic field and an adiabatic passage is performed wherein the Rf pulse is controlled such that: B1 =V A sin 2πνt and ΔH=A(cos 2πνt+s), or B1 =v A cos 2πνt and ΔH=A(sin 2πνt+s), where s=S/A, where S is the frequency offset of a nucleus from the center of the spectrum, and where v allows for variation of B1 throughout the sample, ΔH is the resonance offset of the nuclear spins, and B1 is the rf field of a spin-lock pulse.

High current mass spectrometer using space charge lens

Abstract: Charged particle beam apparatus includes a source 6, 8, 10, 12, 14 for forming a charged particle beam 18 along a beam axis, a mass analyzing magnet 22 for imposing on the beam 18 a magnetic field perpendicular to the beam axis, a resolving slit 24 downstream of the analyzing magnet 22 and a space charge lens 20 positioned between the source and the analyzing magnet in close proximity to the magnet entrance. The apparatus provides a mass spectrometer with high current capability while maintaining the size and weight of the system within acceptable limits. The apparatus is particularly useful in ion implantation systems.

Coding NMR samples for automated changers

Abstract: 57 Analysis samples are presented to an analysis system in respective containers bearing encoded information which is read by optical means and utilized to identify the sample and control the analysis system accordingly.

Sample valve for solute modulated synchronous detection

Abstract: A sample valve for solute modulated synchronous detection alternately directs into a detector a sample gas stream F1 which passes through a modulator cell and a reference gas stream F2 which passes through a balance cell. The sample valve is made of a symmetrically structured chamber with inlets and outlets. An ordinary valve causes a control gas to stream into the chamber alternately though one of two openings to exit openings of the chamber are synchronously opened and closed so that gas streams F1 and F2 are alternately led into the detector and out of the system.

Planar penning magnetron sputtering device

Abstract: An improved magnetron sputter source particularly suitable for magnetic materials is provided in the forming of an unfolded Penning discharge source. The two cathodes are in the form of an inner cathode roughly coplanar with an outer cathode ring. An anode radially between the cathodes is raised above the cathode surfaces so as to block line of sight from the inner cathode surface to the outer. A magnetic flux vector is imposed which passed from one cathode surface to the other. Raising the anode surface about one-fourth inch above the cathode surfaces allows raising the applied voltage so that a source of 5 kilowatts or greater is possible. Raising the anode also spreads the distribution of discharge more uniformly over the target surface and permits low pressure operation thereby facilitating good adhesion and uniform coverage of the substrate.

A UHF-TV klystron using multistage depressed collector technology

Abstract: A program to incorporate depressed collector technology into UHF-TV klystrons was initiated in June 1984. Support for this program was provided by a cooperative group including NASA, National Association of Broadcasters, Public Broadcasting System, transmitter manufacturers and Varian. The objective of the program was to develop a klystron with enhanced efficiency so that in TV service, power consumption would be reduced one half. This paper describes the program accomplishments. A design was achieved using computer aided design technology. Also developed were carbon-coating techniques to minimize the adverse effects of secondary electrons. An experimental 60 kW klystron incorporating the design was constructed. Test data will be presented demonstrating the performance achieved.

Method and apparatus for sample confirmation in gas chromatography

Abstract: A method and apparatus for use in gas chromatography for confirming the presence of compounds in the sample. By directly comparing the transient decay time domain signals of the sample and of known compounds as detected in an ion cyclotron resonance mass spectrometer connected to the chromatographic column, one is able to effect sample confirmation without the computer intensive processes of Fourier transformation and analysis of the resulting mass spectrum.

Higher order modes and instabilities in coupled-cavity TWT's

Abstract: Laboratory records available to the authors, dating back to 1975, report several test CCTWT's troubled by an uncommon "trapped oscillation," explained as a tube section operating as a multigap monotron or extended-interaction klystron (EIK) involving a higher order mode of the interaction circuit. Antisymmetric RF field distributions for these modes tend to make the section a resonator with little external coupling at multiple close-spaced frequencies. All varieties of CCTWT interaction circuit are equally able to support such modes and the list of problem tubes inculpates no type or feature of the circuit per se (as opposed to beam conductance, which was relatively prominent in all). RF fields and propagation characteristics for these modes are discussed in three categories of interaction circuit. When the tube is designed for a given performance as a TWT (based on the conventional mode), parameters such as beam conductance and circuit length and loss combine to determine gain through the well-known TWT relationships. The fact that these parameters combine under very different relationships as regards potential oscillation as an EIK involving a higher order mode, however, helps explain why fairly similar tubes are not all troubled by the instability in question. Since conventional one-dimensional analytic approaches are inadequate for modeling beam interaction with antisymmetrically distributed RF fields, fully three-dimensional modeling capability is looked to as the analytic tool needed to evaluate CCTWT designs (and corrective changes when necessary) relative to the instability discussed.

Emission degradation characteristics of coated dispenser cathodes

Abstract: This paper describes several fundamentally different characteristics of dispenser cathode emission degradation with time. This knowledge is important when predicting useful emission life in applications such as space tubes. The degradation characteristics include a gradual decrease in perveance, an overall work function distribution (WFD) change with time and a work function distribution change with temperature that also changes with time. Along with these effects, "apparent" cathode emission degradation caused by improper gun design is discussed.