Abstract: A pattern is aligned and exposed with a lithography system so that chips larger than the deflection field can be formed by exposing M.times.N fields in a mosaic pattern. The method corrects the deflection field to compensate for the orientation of a previous pattern on a substrate and compensates for errors due to height caused by the beam landing non perpendicular to the target. Two basic procedures disclosed are called "3-mark" which are only applicable to 2.times.2 arrays of fields, and "M.times.N" which covers the general situation, but with slightly less accuracy.

Abstract: A dynamic correction arrangement for an electron beam projection/deflection system provides high order correction values for deflection in accordance with a correction equation. Particularly as applied to high accuracy telecentric deflection, the coefficients of terms of the correction equation may be determined by calibration for a small number of test points. Correction values may be stored in a look-up table or computed in real time by using a math co-processor in a processing pipeline. The correction provided corrects landing angle errors through the third order in telecentric projection/deflection systems such as systems utilizing variable axis immersion lenses.

Abstract: A digital-to-analog converter system includes a logic system which receives input signals, receives an increment/decrement signal, and provides a digital word composed of most significant bits and least significant bits. The system includes two DACs haaving separate data rates and ranges for converting the most significant bits and the least significant bits, respectively, the data rate of the second DAC being greater than the data rate of the first DAC. Combining circuitry produces an analog signal representative of the digital word from the first and second analog outputs. The data rate of the combined output may be as fast as the data rate of the second DAC, and the range of the combined output may be as large as the range of the first DAC. The system also includes track and hold circuitry which holds the value of the output of the first DAC until glitches are settled.

Abstract: A push pull digital-to-analog converter circuit configuration improves the signal-to-noise ratio when used in the common bipolar (both positive and negative) mode of operation, thereby improving its absolute accuracy. Digital data is supplied to a data buffer which includes an inverter. The inverter supplies the data to one of a pair of push pull connected DACS, referred to as dual DACS. The buffer supplies the data to the other DAC without inversion. The outputs of the pair of DACS are combined by an op-amp circuit which takes the two analog outputs from those circuits and combines them while the push pull circuits are opposed so noise is reduced and accuracy of the conversion is enhanced.

Abstract: A three-stage E-beam deflection system employs breaking the entire field to be scanned into clusters and sub-fields. The scanning provided by the first stage of deflection which scans within the entire field is rectilinear and discontinuous with the scan stopping in the center of each of the clusters where an exposure is to be made, and scanning is the same within each cluster from sub-field to sub-field. The scanning within a cluster by the second stage stops in the center of each sub-field where exposure is to be made. The third stage uses high speed electrostatic deflection to provide scanning with a vector scanning mode within the sub-field being scanned.

Abstract: A high speed focus control circuit for an electron beam projection system. The circuit includes a conventional digital to analog converter, comprising a register for storing an n-bit digital value, and n current drivers, each of which provides a current which is proportional to the associated bit weighted value. Rather than summing the currents from all n current drivers and driving a single focus coil, each current driver is connected to one of n individual coils, wound on a common bobbin. This reduces circuit capacitance and permits higher switching speed.