Shutdown svgcoat2 SNF 2009-10-15 14:53:27: Vacuum problem

gsosa at snf.stanford.edu gsosa at snf.stanford.edu
Fri Oct 16 11:40:28 PDT 2009


Large vacuum drop on spindle when flowing with no wafer on chuck. Vacuum would drop to 10" Hg. The vacuum drop was large enough to stop wafer processing on coater #1( vacuum errors on spindle and hotplates). Traced back vacuum hoses to the source in finger wall. THe suppy to the track came from the equipment vacuum source.  The 3/8" supply tube split into 2 3/8" tubes( Tee) , entered the track at the utility plate and supplied vacuum to 2 large vacuum accumulators( 1 for each track). Each vacuum accumulator provides vacuum sources to the variuos modules( spindle vacuum, hotplate vacuum)without significant vacuum drops. The incoming vacuum was unaple to supply enough vacuum to create  a steady state vacuum to both tracks. Removed the Tee's vacuum sourse and plumbed in a second equipment vacuum line from the main vacuum supply in fingerwall. Each track has a dedicated equipment vacuum source. Re-tested open flow vacuum at spindle. Now the vacuum drops to only 19" Hg when no wafer is on the chuck(very stable). Ran both tracks  at the same time with standard programs. All systems OK now. 




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