Last year I asked about the maintenance issues with Cobilt/Quintel Mask
aligners. Here is a summary of the posts I received:

    Ken Westra

1) Cobilt's are an older mask aligner designed for three and four inch
wafers. They were production machines. Quintel was rebuilt them with a
better chuck design. They not actively supported anymore, however
universities and small MEMS start-ups still use them. You can pick thm
up from Bid Service for $ 1500 to $ 2000 US and free if you ask around.

2) Quintel Corp rebuilt the Cobilts and sold them under their name. The
difference between the two is that Quintel solved the laterial shift
problem (between the mask and the wafer) that the Cobilts were notorious
for. Quintel has moved on and is now selling their own product.

3) People have modified these machines to hold multiple objectives on
the microscope (as designed they only hold one). I don't have actual
designs, but I was told that people have used turrets or sliding pieces
with the objectives on them

4) Laterial Shift between alignment and contact positions
"Cobilt lateral alignment shift is due to 4 effects all which can be
managed. 1) particulates as in any contact printer, 2) poor chuck
leveling in the load sequence (which can either be due to excessive play
in the piston [not likely in a quintel rebuild but still possible] or
improper pressure/ vacuum sequencing) 3) warped mask plate (reduced
flatness) 4) too large of an align gap (which is easily adjustable)"
(Thanks to Mark Wendman)

5) Service:
a) Contact Quintel. They are not actively servicing these, but they
still have a few maintenance people from those days still around

b) Ron Becky of BTS phone (609) 768-0150 (Thanks to Myriam Buchbinder)

6) Dimensions
"We regularly use masks with 10 micron minimum distances
with good results, but anything smaller than that tends to be pretty
inconsistent." (Thanks "to Jason Tauscher)