Abstract: An optical system for forming two separate images. A beamsplitter disposed in the path of a converging or diverging beam of light forms a reflected image and transmitted image. A thin positive lens disposed in the path of the transmitted beam of light selectively corrects the transmitted image for any or all of the following problems--spherical aberrations, coma, astigmatism, longitudinal and lateral color.

Abstract: An electrostatic cassette assembly comprising, a cassette body having a central opening for receiving a wafer to be processed in a particle beam lithographic system, a charge plate with a top surface having a coating of dielectric (nonconductive) material or a plurality of nonconductive means, or both, on which the wafer is supported, means for forcing said charge plate and wafer into contact with stop means to hold the wafer rigidly in said cassette assembly, and means for applying a potential difference between the wafer and the charge plate to flatten said wafer by Coulombic force so that the wafer is held both mechanically and electrostatically in said cassette assembly. Means are also provided for insuring a good electrical contact with the wafer and for aligning the wafer in the cassette assembly.

Abstract: Disclosed is a detector for determining the location of wafers moving in a sputtering system, for example, to and from the sputtering chamber where the wafers are processed, including a capacitive transducer, located in the path of travel of the wafers, to which is coupled an oscillator supplying a constant current thereto. This current is detected by a sensor, whose output is processed and applied to a comparator. The comparator is preferably preset to supply a digital "0" when the current through the transducer is at a static or no-wafer condition, and a digital "1" when the capacity of the transducer changes due to the presence of a wafer in close proximity to the transducer which is sensed as an increase in current which is reflected as a change of voltage level applied to the comparator.

Abstract: Anisotropic etching of thick photoresist under plasma conditions to achieve a vertical side wall with or without undercutting is accomplished by operating at a low excitation frequency, a pressure in the range of 0.3 to 2 Torr and a controlled concentration of active species.

Abstract: A modified cordierite (2MgO.2Al.sub.2 O.sub.3.5SiO.sub.2) composition in which at least a portion of the silicon dioxide is replaced with germanium oxide. These compositions have low thermal expansion, excellent formability and thermal shock resistance making them especially suitable for the manufacture of mirror substrates to be used at elevated temperatures. By selecting the proportion of germanium oxide according to the intended operating temperature, substantially zero thermal expansion can be achieved between room temperature and the selected operating temperature. Methods of manufacturing the material and of selecting the thermal expansion characteristics are also disclosed.

Abstract: In particle beam optical instrumentation, an array of conventional sputter ion pump cells distributed in a ring shaped array about the circumference of the volume (optical column) to be pumped. An axially symmetrical, hollow, toroid magnetic circuit, formed by axially symmetrical magnets, either of the permanent type or of the electromagnetic type (or a combination of both), is used and the pumping action is outward from the central throughbore in the column so that the bore space could be occupied by other instrumentation. The magnetic circit may be used for particle beam focusing (optical lens) as well as for the pumping action by introducing magnetic gaps in either a series or parallel configuration.

Abstract: A discrete-time analog filter for eliminating a variable frequency carrier of an amplitude-modulated signal. The filter comprises a plurality of unit delay circuits, each of which is sampled at a rate which varies in proportion to the frequency of the carrier so as to automatically tune the filter's reject band to follow the carrier frequency.

Abstract: The disclosed circuitry for integrating an analog voltage signal with respect to time, t, while simultaneously dividing the integral by time, t, is valuable for use in medical pulmonary analyzers and includes a ramp generator for developing a voltage level proportional to time, a duty cycle modulator for generating an inverted time signal, 1/t, a multiplier for multiplying the analog voltage signal, V, by the inverted time signal, 1/t, followed by an integrator to produce the required output of 1/t .intg.V dt.

Abstract: An apparatus for automatically compensating for deviation of a capacitance manometer reading from true pressure. The capacitance manometer is connected to a source of pressure having a value less than the pressure the capacitance manometer is capable of reading and the indicated pressure is stored as a correction factor. Thereafter, each pressure read by the manometer is adjusted by the correction factor.

Abstract: A system for machining a glass workpiece comprises means for rotating the workpiece. A concentrated beam of energy is axially directed to the surface of the workpiece to soften the glass material. The softened glass material is then removed by a pointed or relatively narrow tool which is precisely located with respect to the area treated by the energy beam.

Abstract: An R.F. generator for providing power to a load via a transmission line wherein load impedance is automatically matched to the surge impedance of the transmission to provide maximum transfer of energy from the generator to the load. Voltages representative of input power and reflected power are utilized to control a load match circuit to cause load impedance to equal transmission line impedance. Feedback loop means are also provided to maintain net load power at an externally commanded level.

Abstract: A flowmeter system having a device defining a path for confining the flow of a fluid medium therethrough, first and second transducers disposed along said flow path for generating and receiving acoustic compression waves in the fluid medium between the transducers, a phase lock loop transmit/receive system including a voltage controlled oscillator for adjusting the frequency of the acoustic compression waves to maintain the compression wave length constant, a phase detector for measuring the phase difference of the received acoustic compression waves relative to that transmitted and for producing a sum signal proportional to the sum of the measured phase differences to vary the output of said voltage controlled oscillator, circuitry for producing a difference signal proportional to the difference of the measured phased differences representing the direction and magnitude of the flow of the fluid medium as well as changes in its composition, and circuitry for adjusting the phase of the transmit signal during i

Abstract: A flowmeter system having circuitry defining a path for confining the flow of a fluid medium therethrough, first and second transducers disposed along said flow path for generating and receiving acoustic compression waves in the fluid medium between the transducers, a phase lock loop receiver/transmitter system including a voltage controlled oscillator for adjusting the frequency of the acoustic compression waves to maintain the compression wave length constant, a phase detector for measuring the phase difference of the received acoustic compression waves relative to that transmitted and for producing a sum signal proportional to the sum of the measured phase differences to vary the output of said voltage controlled oscillator, circuitry for producing a difference signal proportional to the difference of the measured phase differences representing the direction and magnitude of the flow of the fluid medium as well as changes in its composition and an active filter in the loop for increasing the loop gain of t

Abstract: A high speed temperature controlled, microcircuit electrometer comprising a preamplifier with a very high resistance feedback resistor and temperature sensor on a substrate which is temperature controlled by a thermo-electric module on which the substrate is mounted and which is held within a very small temperature range by temperature control circuitry. The preamplifier, feedback resistor, temperature sensor and thermo-electric module are all enclosed in a hermetically sealed, dry gas environment, maintained at an essentially constant temperature, to reduce the effects of hostile environments, such as temperature changes, vibration, contamination, and humidity. This electrometer operates at high speed and is highly responsive to small current values such as ion currents generated by ionized gas molecules in a mass spectrometer.

Abstract: A high track density recording head assembly which eliminates cross-talk in high track density recording systems by positioning very thin neutralization heads between each pair of adjacent recording heads. The neutralization heads are provided with air gaps aligned with the gaps in the adjacent heads and have coils wound to develop a polarity opposite to that in the adjacent recording head. The neutralization head flux thus produced cancels the recording head lateral fringing flux that is responsible for recording interference in the adjacent recording tracks.

Abstract: Apparatus for the etching of semiconductor devices which includes, in combination, an etching chamber containing the semiconductor device to be etched, an electrodeless etching plasma forming chamber having an inlet connected to a source of continuously flowing etching gas and having an outlet connected to said etching chamber in fluid flow communication; a helical inductive resonator coupler for coupling a source of R.F.

Abstract: This invention relates to a plasma etching system, which includes a lower flange and a spaced upper flange; a chamber wall mounted between the flanges to form a closed etching chamber; a grounded wafer support plate disposed in said chamber for receiving thereon a wafer to be processed; an electrical insulating element interposed between the chamber wall and the support plate; a sintered or sintered-like porous electrode plate mounted in the chamber in spaced relationship with respect to the wafer; said plate having a gas inlet for receiving a supply of etching gas; circuitry for applying an excitation voltage to this plate, and said chamber having a gas outlet leading to a vacuum source.

Abstract: An apparatus for controlling the volume of flow of a gas. A reference volume has an input conduit connected to the source of gas and an output conduit connected to a utilization device. Valves in the input and output conduits are cyclically controlled to permit pressure in the reference volume to reach a high and then to attain a low. The reference volume pressure is measured twice during each cycle to provide voltages representative of the high and low pressures. Circuit means control the time and duration of operation of the valves to cause the difference between the high and low pressures to equal a predetermined value.

Abstract: In a ring field projection optical system for imaging a mask on a wafer the illumination source has readily adjustable means for obtaining uniform exposure along the length of the arcuate zone of illumination.

Abstract: A target for use in aligning masks used in producing microcircuits which is of a size that can be printed on a microcircuit chip without interfering with the lines thereon, consisting only of lines vertically or diagonally disposed with respect to the image transducer is disclosed. Also disclosed is an automatic system for aligning such targets.