Method and system for processing wafer

A method of processing wafer, comprising:

• providing a pump for extracting gas from a chamber via a first route and pumping down a second route to chuck a wafer placed in the chamber;
• closing a valve of the second route to stop chucking the wafer;
• and
• purging a join of the first route and the second route by another gas.

A system for processing wafer, comprising:

• a first pipe, connecting a chamber and a pump, and configured for the pump to extract gas from the chamber;
• a second pipe, connecting the chamber and the first pipe, and configured to be pumped down by the pump for chucking a wafer placed in the chamber;
• and
• a third pipe, connecting the second pipe and a gas source, and configured for the gas source to provide gas to purge a junction of the first pipe and the second pipe.