Texas Instruments Corporation

Nikon Corporation

Denis F Spicer

Michael R Sogard

Thomas J Aton

Simon C Garth

John N Sackett

Christopher T Black

A linear brushless electric motor ( ) including a magnet component ( ), a conductor component ( ) that interacts with the magnet component ( ) and a control system ( ) for directing current to the conductor component ( ) is provided herein. Uniquely, the conductor component ( ) includes an auxiliary conductor array ( ) that reduces stray magnetic fields generated by the electric motor ( ), without significantly influencing the dynamic performance of the motor ( ) and without significantly increasing the size of the motor ( ). Because of the conductor component ( ) provided herein, the motor ( ) is particularly useful in manufacturing, measurement and/or inspection processes that are sensitive and/or influenced by stray AC magnetic fields. More specifically, the present invention is particularly useful with an exposure apparatus ( ) that utilizes an illumination system ( ) that generates a charged particle beam, such as an electron beam.

Brushless electric motors with reduced stray AC magnetic fields

An air bearing is usable in a vacuum, by restricting the air escaping from the air bearing to the immediate vicinity of the air bearing. This is accomplished by one or more pump-out slots concentrically surrounding the air bearing orifice, and by concentrically surrounding the outer pump-out slot with a sealing sheet which confines air escaping from outside the pump-out slots to within the perimeter of the sealing sheet. The sealing sheet is a compliant mechanical 'wall', making only marginal contact with the bearing support surface, and is not a high friction seal. Hence free movement of the air bearing structure on the supporting surface is allowed, thus making this air bearing compatible with for instance an XY stage used in a vacuum chamber.

Air bearing operable in a vacuum region

An electron beam imaging system (10) includes a photoemitter plate (12). An optical image beam (15) is directed through a pattern mask (18), which is imaged onto the photoemitter (12). The photoemitter (12) emits electrons from those unmasked regions illuminated by the optical image beam, emitting an extended-source electron beam that carries the mask image. The extended-source electron beam is focused (34) onto a device under fabrication (40), providing a single-stage electron lithographic patterning function. The optical source (16) is chosen so that optical image beam energy is nearly identical to the work function for the photoemissive coating (14) of the photoemitter (12). As a result, the photoemitter (12) emits electrons with substantially zero kinetic energy, allowing the emitted electrons to be accelerated through the electron beam focusing elements (34) with very nearly identical electron velocities, thereby minimizing chromatic aberrations. In one embodiment, an aperture (85) is used to limit the extended-source electron beam to those electrons with trajectories requiring no more than a maximum amount of focusing, thereby minimizing spherical aberrations.

Extended source e-beam mask imaging system including a light source and

An electron beam imaging system (10) includes a photoemitter plate (12). An optical image beam (15) is directed through a pattern mask (18), which is imaged onto the photoemitter (12). The photoemitter (12) emits electrons from those unmasked regions illuminated by the optical image beam, emitting an extended-source electron beam that carries the mask image. The extended-source electron beam is focused (34) onto a device under fabrication (40), providing a single-stage electron lithographic patterning function. The optical source (16) is chosen so that the optical image beam energy is nearly identical to the work function for the photoemissive coating (14) of the photoemitter (12). As a result, the photoemitter (12) emits electrons with substantially zero kinetic energy, allowing the emitted electrons to be accelerated through the electron beam focusing elements (34) with very nearly identical electron velocities, thereby minimizing chromatic aberrations. In one embodiment, an aperture (85) is used to limit the extended-source electron beam to those electrons with trajectories requiring no more than a maximum amount of focusing, thereby minimizing spherical aberrations.

Extended source E-beam mask imaging system and method

Electron beam apparatus for use in testing integrated circuits uses a magnetic electron objective lens having a first end adjacent the circuit under test and a second end remote from the circuit. The magnetic field of the lens increases steeply to a maximum near the first end and falls gradually towards the second end. Secondary electrons emitted from the circuit are accelerated strongly by an electrostatic field into the first end of the lens and are retarded abruptly to speeds of the same order as their emission speeds in the region of maximum magnetic field. Further gradual retardation of the electrons takes place so that the electrons approach the second end of the lens parallel to the axis of the lens at substantially their emission speeds. A filter grid located at the second end of the lens and a collector of electrons passing through the filter grid enable the emission speeds of the secondary electrons to be measured.

Electron beam apparatus and method for detecting secondary electrons

An apparatus and a method for monitoring the functioning of an integrated circuit in operation using an electron beam directed to a particular node of the circuit which is of interest and measuring the energy of the secondary electrons emitted, in which the energy measurement is made using a filter grid, the bias on which is set by comparing a voltage representing the rate of receipt of secondary electrons past the filter grid with a reference voltage and adjusting the bias in response to the comparison so as to reduce the number of electrons received. A current is produced proportional to the difference between the two voltages and applied to charge a capacitor, the voltage on which is used to set the voltage on the filter grid. The electron beam may be pulsed and the comparison gated in synchronism with the pulsing but delayed relative to it so that the control of the filter grid bias is effected only when the signal due to the secondary electrons emitted in response to the beam pulse is received by the comparator.

Electron beam testing of integrated circuits

A magnetic field generator having a conductor winding shaped to lie over the surface of a cylinder such that four pairs of straight conductor elements lie parallel to the axis of symmetry (Z axis) of the cylinder equally spaced around its periphery. These elements are joined by 90 degree arc conductor elements. The winding is such that in the straight elements of each pair, current flow is the same direction while in adjacent peripheral elements, current flow is in opposite directions so that the magnetic field due to the current flowing through the peripheral elements is zero on the Z-axis while the current flow through the straight elements forms a quadripole magnetic field about the Z-axis. Modifications of the structure can be made to provide for six-pole, 8-pole, 12-pole, etc., structures. In each case, a single conductor formed into an appropriate sequence of meanders can be used to produce the desired structure, thereby simplifying fabrication. Such structures have the advantage of reduced winding induction in relation to the magnetic field strength produced by the coil structure and are particularly suited for use in electron beam machines, for example, in the provision of an astigmatism correction coil.

Magnetic quadripole

A line interlaced video signal having odd and even alternating fields produces an alphanumeric character display in the form of a dot matrix character, each matrix location comprising segments of two next adjacent lines in the display. To improve the resolution of the characters, diagonals are detected and partly filled to provide a rounded effect. Two parallel-in serial-out shift registers are used, one of the shift registers having an associated input buffer store. A binary word representing dot information for one row of a character is read out from a dot matrix character generator ROM and loaded into one of the shift registers. On even (odd) fields the ROM output for the previous (succeeding) row is read and loaded into the other shift register. The last two bits of the two shift registers are compared to detect diagonals in the character information and used to modify the video signal to lengthen the leading or trailing edge of the corresponding dot to produce the rounded character.

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Bedford, United Kingdom

Denis F Spicer