15 days electron beam exposure for manufacturing of large area silicon based NIL master

• For the 1st time, a 300 mm bare Si wafer was exposed for 355 h (approx. 15 days).
• A variable shaped e-beam using a commercially available positive tone CAR was used.
• A linear resist degradation was observed resulting in a CD variation of 6.8 nm (3 σ).
• After 325 h of exposure, the shape size correction of e-beam is not working properly.
• Additionally to the resist degradation, the CD variation of contact holes increases.

In this paper, the feasibility of a large area exposure for the manufacturing of a NIL master (silicon wafer) dealing with a long writing time is shown. Fraunhofer CNT succeeded in a 355 h exposure with a variable shaped e-beam using a commercially available positive tone chemically amplified resist. The wafer has been evaluated in terms of resist contrast and stability, CD uniformity, linearity, pattern quality and defectivity. Electron beam tool parameters like Wehnelt voltage and stage temperature have been analyzed. Different writing strategies and concepts will be considered to optimize the exposure and minimize stitching error defects.

Figure optionsDownload as PowerPoint slide