Exposure method utilizing partial exposure stitch area

A method for forming a desired pattern on the surface of an object by exposing the surface of the object with an exposure apparatus having a main deflector and at least one-stage sub-deflector, comprising the steps of:

• dividing an area to be exposed into a plurality of fields each being determined by the deflection width of the main deflector;
• dividing each field into a plurality of sub-fields each being determined by the deflection width of the sub-deflector;
• applying a sequential exposure process to each field by using a variable shaped electron beam, and applying a multiple exposure process to an area where adjacent fields overlap each other,
• wherein:
• said multiple exposure process is conducted in the area in units of sub-field,
• the exposure dose at each of exposure unit is determined such that the total exposure dosage in the area subject to the multiple exposure process is set equal to an exposure dosage for single exposure at each of exposure units, the exposure dosage in said area subject to multiple exposure process is increased in steps, within the range between a least exposure dose and an exposure dose less than a predetermined exposure dose by the least exposure dose, in the direction perpendicular to the longitudinal direction of the boundary portion from the outer edge of the field towards the inside of the field,
• an exposure dosage in the area subject to the multiple exposure process is determined on the basis of the minimum exposure dosage available in the exposure apparatus.