A small chamber between the room and a process chamber, with a door or valve on each side. Wafers or parts go in, the load lock is pumped to a set pressure, and the inner valve opens for the transfer, so the main chamber stays at high vacuum and never takes on water from room air. Fab cluster tools often carry two load locks so one can cycle while the other feeds the tool.
Load lock takes ninety seconds to pump, that's what's capping throughput on this tool, not the process.
Also heard as
- loadlock
- LL
- airlock
Related terms
Gate valve
Full-bore valve with a sliding plate that isolates a high vacuum pump or a load lock from the chamber.
Rough out
To pump a vented chamber from atmosphere to crossover with the roughing pump, before the high vacuum valve opens.
Vent
To let gas back into an evacuated chamber, usually dry nitrogen, to bring it up to atmosphere.
Wet
Said of a chamber whose walls still hold adsorbed water, so it pumps down slowly and stalls high.