Browse Prior Art Database

BUILT IN INFRARED ALIGNMENT TARGETS FOR THERMAL INK JET

IP.com Disclosure Number: IPCOM000027658D
Original Publication Date: 1998-Aug-31
Included in the Prior Art Database: 2004-Apr-08
Document File: 2 page(s) / 90K

Publishing Venue

Xerox Disclosure Journal

Abstract

Disclosed is the use of polysilicon heater elements in alignment area targets of thermal ink jet wafer pairs. The polysilicon heater elements are heated to emit near infrared radiation for wafer alignment. Since an infrared light source is incorporated on the surface of the heater wafer, a single side polished wafer can be used.

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XEROX DISCLOSURE JOURNAL

BUILT IN INFRARED ALIGNMENT TARGETS FOR THERMAL INK JET William G. Hawkins

Proposed Classification
U. S. C1. 347/026 Int. C1. B41j 2/165

Disclosed is the use of polysilicon heater elements in alignment area targets of thermal ink jet wafer pairs. The polysilicon heater elements are heated to emit near infrared radiation for wafer alignment. Since an infrared light source is incorporated on the surface of the heater wafer, a single side polished wafer can be used.

Accurate alignment of the heater and channel wafer pair is important for good thermal ink jet die module performance. At the present time, the wafer pair is aligned by use of double side polished heater and channel wafers. The double side polished wafer pair allows infrared light transmission without diffuse scattering. Alignment targets are built into the confronting surfaces of the wafer pair. The heater wafer alignment target is aluminum (opaque to infrared) while the channel wafer alignment target is an orientation dependent etched house roof structure that diffracts light at an oblique angle, and therefore, also appears opaque in transmission. The heater wafer target is an oversized frame and the channel wafer target is an opaque square which fits inside it.

This disclosure suggests the construction of polysilicon heating elements on the top surface of the heater wafer. The polysilicon heating elements are connected to aluminum metallization and routed to bonding pads to form a probe. Identical processes are used for...