Proximity correction method for E-beam lithography

Method of proximity correction in an E-Beam lithography system for exposing, on an E-beam sensitive resist, a design comprising at least one design shape, the method comprising;

• contracting each design shape by a predetermined bias to form a contracted design shape wherein the shape control requirement is that each contracted design shape be enlarged, on development, by the value of the predetermined bias;
• and
• determining the E-beam dose required at any given point of the design such that, on development, a shape control requirement is satisfied, wherein the determination of the E-beam dose:
• a) is made in accordance with a predetermined relationship between an indicator and the required E-beam dose, the indicator being indicative of the degree of the proximity effect at any point on the design;
• b) is constrained so that the dose is zero at points not on a design shape;
• and
• c) comprises the step of calculating the solution of an integral equation relating the indicator to the E-beam dose distribution at least at a plurality of points on the design.