Etec Systems, Inc.

Applied Materials, Inc.

Richard W Prior

Frank E Abboud

The present invention relates to bi-directional raster scanning (&ldquo;serpentine scanning&rdquo;) for an electron beam lithography system. Improved circuit components are described for generating the true triangular waveform required in bi-directional scanning. The circuitry of the present invention provides control of signal amplitude, frequency and phase to better than 1 ppm by making use of signal generation circuitry described pursuant to the present invention. A series of coarse and fine tuning delay adjustments pursuant to the present invention accommodate a variety of operating conditions. Another embodiment of the present invention relates to an optimization of the data path hardware for bi-directional scanning, including isolating a section of the data path hardware specifically to provide calibration scans. The delay circuit built into the data preparation hardware helps compensate for delays caused by finite bandwidth in the analogue drivers. A two-level beam deflection is described in which fast, low-voltage electrostatic deflectors are employed (preferably one for each scan direction) in conjunction with a slower magnetic beam deflector. The two level deflection system pursuant to the present invention allows for controlling the retroscan signal to match the polarity of the main magnetic deflection signal.

Bi-directional electron beam scanning apparatus

An electron gun assembly which integrates electronics required to power the electron gun and the electron gun itself in one module in a high voltage operating environment. The assembly has four major sections: interface cables; electronic circuits (active and high voltage); the electron emitter; and a mechanical enclosure for the assembly. The electronics portion of the assembly has two distinct sections: an active electronics section (which contains digital to analog converters, interface to a control computer, and analog outputs terminals to control the high voltage electronics) and a high voltage electronics section (which contains high-voltage multiplying circuits and feedback and filtering elements). These two sections are electrically connected and are present within an internal box at one end of the assembly, or alternately, the high voltage electronics section is disposed below the active electronics section and outside the internal box. The high voltage electronics section, in turn, is electrically connected to the electron emitter by soldered wiring or alternately, by a mating connector. The integration of the major sections of the power supply for the electron emitter with the electron emitter in one assembly eliminates the bulky, complex and expensive cables relied on in previous designs. Additionally, by modularizing the design so that the active electronics (which are the most prone to failure) are present within the internal box located at one end of the assembly, serviceability in the field is made easier.

Integrated electron gun and electronics module

A method of electronically measuring parameters of an beam in a raster scan system includes the steps of: choosing a predetermined pixel to be calibrated, moving a grid adjacent this pixel, strobing the beam, incrementally moving the beam toward an axis of the grid, and integrating the signal resulting from the beam as the beam moves toward the axis. The steps of strobing the beam, incrementally moving the beam, and integrating the signal are repeated until the beam crosses the axis. The value of the accumulated signals, provided for example by a charge amplifier, is used to determine the relative position of the axis of the grid. The value of the accumulated signals associated with another axis is also determined. The relative positions of the two axes determine the relative location of the grid. If the grid location is known, the location of an associated substrate which is typically adjacent the grid is also known.

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Fremont, CA, United States of America

Richard W Prior