Strange pattern on Tek CCD chip

[Michael P. Lesser]

Hi Jim,

Last year I repaired a broken wire bond on a Tek CCD for CTIO which had the
same surface pattern seen in ESO's crocodile image.  I saw it through the
bonder microscope, I did not image the CCD.  The CTIO folks might be able to
say more about what the images from that CCD look like.

I think the problem is a cracked AR coating, although I have created similar 
patterns on back illuminated devices when our oxidation process went wrong.

There is a considerable stress generated in some AR coating layers due
to the expansion coefficients of the materials and the depoistion 
process. 

-Mike Lesser