Research Disclosure

摘要

The present development relates to Wafer Stages, such as may be applied in lithographic machines and processes. More specifically,the present development relates to Increasing a wafer stage pressure to improve defectivity by adding a diffuser in center of the wafer stage. Wafer defectivity on EUV system is a challenge for Extreme Ultraviolet lithography at this moment. A potential solution is flow shielding. However, despite such improvement, a present analysis indicates extra improvement may still be required. The main idea of (he present development is to increase a wafer stage pressure by adding an extra H2 inlet, while keeping pumps at their designed operation mode, so as to overcome the disadvantages/risks due to switching off pumps or pump tuning. Accordingly, an diffuser is added in center of the wafer stage e.g. with separate controller to regulate pressure to higher levels. The added diffusor may be used to disperse the incoming gas to vacuum with low velocity.