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Digital Magnetic Corrections Calculator For E Beam Lithographic Systems Disclosure Number: IPCOM000067054D
Original Publication Date: 1979-Jun-01
Included in the Prior Art Database: 2005-Feb-20

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Trotter, RR [+details]


E-beam lithographic systems require deflection corrections to compensate for errors caused by linear drifts, wafer rotation, magnification differences and pin-cushion effects. The sequential digital calculator, described below, produces magnetic deflection correction terms for the X and Y axes that are 14 bits wide. The correction terms are calculated using nominal X and Y vector scan positions (12 bits each) and software derived correction coefficients. The nominal positions and resultant correction terms are converted to beam deflection currents using digital to analog conversion techniques. The X and Y magnetic correction algorithms are: Delta Xm = Ai + A + BXm + CYm + DXm Ym Delta Ym = Ei + E + FXm + GYm + HXm Ym