Subject: Please report if you are seeing star shaped or trillium shaped patterns at the end of your exposures.
From: James Conway <jwc@snf.stanford.edu>
Date: Thu, 10 Jun 2004 18:41:00 -0700
Thu, 10 Jun 2004 18:41:00 -0700
Greetings:

Two weeks ago KaiMei Fu reported an odd looking feature in her patterns written with UV-N 30 exposed at 1 uC/cm^2 dose.
I have attached an images of this type of defect.


During PCM testing this week on 100 nm PMMA I have also started seeing this artifact at the position the system comes to at the end of the writing job.  It is always located in the upper right hand corner of a writefield but outside the write fields area.
I will be doing more test tomorrow to determine if this is leakage from the beam blanking circuit, or from a flash as the EHT power supply ramps down on EHT turn off at the unloading sequence.

Users are encouraged to be especially vigilant in their inspections and please report your results to this list with high priority.

Thank you,

James Conway


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