| Popis: |
To extend the effectiveness of photo lithography, Optical Proximity Effect Correction (OPC) and Resolution Enhancement Technique (RET) incorporate increasingly complicated process steps, handling large volumes of data. This poses a challenge for mask making with EB lithography in two areas: data transfer speed and the reliability of pattern data processed by hardware. Traditionally, JEOL's variable shaped beam mask writers used single board CPU control to save in buffer memory pattern data per field on a magnetic disk. We developed a new parallel transfer technique using a dual board CPU to enhance the data transfer speed to buffer memory. This technique improved the data transfer speed from 40 MB/sec to 80 MB/sec or higher. To insure the reliability of pattern data processed by hardware, we also devised a way to save in the hard disk the shot position, size, and dose of patterns processed in the data transfer system. We verified that the system was able to record in real time 250G shot pattern data (size and positional data of figures to be exposed). |
