A layout is decomposed into partial patterns. An intermediate mask is drawn for each of the partial patterns. The intermediate masks are used in a mask stepper or scanner progressively for projection again into a common pattern on a test mask. A line width distribution LB(x,y) is determined from the test mask or from a test wafer exposed using the mask, and is converted into a distribution of dose corrections. The transmission T(x,y) of the respective intermediate masks is adapted based upon the calculated dose correction. This can be achieved using additional optical elements which are assigned to the intermediate masks and have shading structure elements, or by laser-induced rear-side introduction of shading elements in the quartz substrate of the intermediate masks themselves.