Biological lithography: Improvements in DNA synthesis methods

We have recently succeeded in synthesizing long oligonucleotides (90-mers) with high yield. This synthesis requires 360 virtual masks, and thus puts challenges on image placement and local contrast. We have updated our DNA synthesis modeling to Monte Carlo simulation from numerical approach. We also devised a method, called "Inverted Capping." to remove sequence errors from edge scattering of light, which provides a large error reduction and the possibility of fabrication of higher resolutions. Finally, we have also implemented an image locking method to eliminate image drifts. (C) 2004 American Vacuum Society.