This is a classic picture (from Ernst Kratschmer) showing how large features can be fully exposed while small features are underexposed. It’s a very old picture, and somewhat of an exaggeration, but you get the point: If this pattern were exposed at a higher dose, then the small features would develop properly while the large features bloom out and increase in size. These days we are using 100kV electrons and the effects are much more subtle. For example, if you are writing a 300um wide grating, then the lines at the edges will get about 10% lower dose than features in the middle. If you don’t care about the edges, then don’t worry about it! Are you worried? Ok, then let’s consider a few common solutions.