Pattern drawing apparatus using charged beams

Claim 1

A raster scan type charged beam pattern drawing apparatus including a bit data conversion circuit for converting IC pattern data into bit data which is in a one-to-one correspondence with a pattern to be drawn by the IC pattern data, a bit map memory for storing the bit data from said bit data conversion circuit, and a read circuit for reading out bit data from said bit map memory in synchronism with a scanning operation of a charged beam having a fixed size, and applying the bit data to means for controlling on/off of charged beams; wherein said apparatus comprises: a pattern re-size circuit for selectively magnifying and reducing the size of a part of a peripheral portion of a pattern expressed by the bit data without changing a portion thereof said re-size circuit comprising an output extracting means for extracting the bit data stored in said bit map memory, which corresponds to a specific address in a processed pattern and a plurality of adjacent addresses surrounding said specific address; re-size parameter setting means for setting data either "1" or "0" corresponding to each of said adjacent addresses, depending on the direction of magnification and reduction of the re-sized pattern; and logic/arithmetic means for logically operating the data at the plurality of adjacent addresses surrounding said specific address, which is extracted by said output extracting means, and the data corresponding to said adjacent addresses as set by said re-size parameter setting means, to determine the bit data at said specific address, and to supply it to said pattern re-size circuit.