Advanced e‐beam lithography

The acceleration voltage dependence of electron‐beam (EB) lithography was investigated. A low acceleration voltage is suitable for a mask (reticle) of several magnifications, because the proximity effect correction is not required. A reticle writing system EX‐8 with an acceleration voltage of 12.5 to 20 kV has been developed. A high acceleration voltage is preferable for the direct writing of fine patterns. A direct writing system EX‐7 with a typical acceleration voltage of 40 kV has been developed. A new shaped beam calibration method and a new astigmatism correction method have enabled the EX‐7 to write a pattern with 0.1 μm. High accuracy shaped beam calibration and alignment as required by small patterns were realized for a high acceleration voltage.