Dave Fish,

First, the color of the overglaze (to my knowledge) cannot be changed by the end user. It is purchased to the desired specifications. For overglaze products, visit the web site for a thick-film product supplier such as Emca-Remex or more specifically their data sheets on overglaze. ( I think the 7550D for example is transparent blue )

As far as the fiducials go, we placed 20 mil circles in the corners of the substrate printed on the same layer with the Pt/Pd/Ag conductors (our substrates were single conductor layer). After firing the conductors, a protective overglaze layer was printed and fired. On the overglaze layer, we did NOT unmask the area around the fiducials which put a transparent blue masking over the Pt/Pd/Ag fiducial. This masking cut the glare from the fiducial recognition camera and allowed 100% recognition.

I hope this answers your questions.

-Dave R.


David Ratte
Mfg/Process Engineer
Superior Circuit Technologies, Inc.
Tel  (407) 733-7021
Fax (407) 733-7118
[log in to unmask]
http://www.superiorcircuits.com



----------
From:  David Fish [SMTP:[log in to unmask]]
Sent:  Friday, October 30, 1998 10:08 AM
To:  TechNet E-Mail Forum.; David Ratte
Subject:  Re: SMT Assembly on Ceramic substrate?

David Ratte in you response to Enza Hill, you mentioned: "At a previous
employer, we solved our fiducial problems by glassing over the
fiducials."

How do you glass over fiducials?
How do you change color of the glass?

Dave F

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