Electron-beam lithography is one of the techniques used in transferring circuit patterns onto substrates. Proximity effect caused by electron scattering imposes a severe limitation on the ultimate spatial resolution attainable by E-beam lithography. Therefore, proximity effect correction is essential particularly for fine-feature, high-density circuit patterns. Proximity effect correction is very time-consuming due to intensive computation required in the correction procedure and a large size of circuit pattern data to be processed. Therefore, it is an ideal candidate for distributed computing where the otherwise-unused CPU cycles of a number of computers on a network (cluster) can be efficiently utilized. One of the characteristics of such a cluster is its heterogeneity, i.e., the available computing power varies with computer and/or time. This variation may degrade performance of distributed computing significantly. In this paper, a distributed implementation of proximity effect correction, and static and dynamic load balancing schemes which attempt to minimize execution time of distributed proximity effect correction by considering heterogeneity of a cluster and non-uniformity in a circuit pattern, are described. Also, experimental results obtained on a cluster of Sun workstations shared by multiple users are presented.