THERMAL INK JET WAFER PAIR TACKING WITH BUILT-IN HEATERS
Original Publication Date: 1998-Aug-31
Included in the Prior Art Database: 2004-Apr-08
Xerox Disclosure Journal
Disclosed is the use of polysilicon heater elements to locally heat tack an adhesive so that it cures and temporarily bonds a heater and channel wafer together. Accurate bonding of thermal ink jet wafer pairs is essential for good die module print quality and drop ejection. At the present time, it is difticult to reliably tack the heater and channel wafers together. Once the wafer pair is tacked, the pair is then vacuum laminated to force intimate contact between the heater and channel wafers. If the tack is not sufficient, the wafers are observed to slip when laminated, and the features become misaligned. One problem with tacking is that features (tack holes), which can readily be etched in the channel wafer, look like inverted funnels (broad at the base), so UV curable adhesives cannot be easily used. Anaerobic adhesives tend to run between the channel and heater wafers and cause spreading of the pair. When vacuum lamination is performed, the pair stays separated around the tack holes.