Marc R Bergeron

US Patent:

47180196, Jan 5, 1988

Filed:

Jun 28, 1985

Appl. No.:

6/749644

Inventors:

Timothy I. Fillion - Burlington MA
Marc L. Bergeron - Bedford MA
Andrey Varpahovsky - Brookline MA

Assignee:

Control Data Corporation - Minneapolis MN

International Classification:

H01J 3700
G06F 1540

US Classification:

364491

Abstract:

In an electron beam system in which the beam is exposed in selected prescribed patterns on a target surface, stored pattern data specifies the location of the pattern as coordinates on the target plane of a reference point in the pattern, specifies the shape of the pattern as a code identifying one of several permissible shapes, and specifies the size of the pattern as dimensions of first and second pattern dimensions in the target plane. In exposing each pattern, the data is: modified to provide the selected pattern in the desired size; modified to determine the maximum beam size for the selected pattern; dynamically fragmented into individual beam flashes; and examined to determine the beam spot size, shape and position for each flash. All patterns are generally designated as trapezoids, with a triangle considered as a trapezoid having one side of zero length, a rectangle considered as a trapezoid having four right angles, etc.