Hi,
We use 1813 resist to image LOR 5B, and develop with 319 developer (which etched
LOR 5B). Undercut can be very fast (maybe 1 um for 10 seconds over-etch) but we
found that increasing the bake time for the LOR helps the problem.  Currently I
bake LOR 5B at 200 deg C. for 10 Minutes.

-Bill


> Does anyone have any experience using LOR with Shipley 1800 series as the
>imaging resist for lift-off metallization? I have been evaluating the LOR B
>resist and find that the undercut rates I get are much higher (up to 4
>times) than that shown in the datasheet. I have been using exactly the same
>processing conditions as specified  but can't reproduce the rates that are
>shown in the datasheet.