Controlled layer of tantalum for thermal ink jet printer
AssigneeLexmark International, Inc.
InventorCharles Spencer Whitman
Life of this patent
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Abstract
A thermal ink jet printhead has a protective layer of Ta with an optimum thickness of about 9,000 A deposited on a protective layer of SiC under deposition conditions determined by a regression equation. The protective layer of SiC has an optimum thickness of about 5,000 A. The life of a thermal ink jet printhead having these two optimum thicknesses is at least twenty times the life of a thermal ink jet printhead not having these two optimum thicknesses in at least one embodiment. Etching of the layer of SiC prior to depositing the layer of Ta further increases the life of a thermal ink jet printhead.
Claims8
A thermal ink jet printhead including:
- a rigid substrate;
- a layer of heat insulating material overlying said substrate;
- a resistive heating layer overlying said layer of heat insulating material;
- an electrically conductive layer overlying only portions of said resistive heating layer to leave other portions of said resistive heating layer exposed to function as heaters for ink;
- a protective layer of silicon nitride of a selected thickness overlying said electrically conductive layer and the exposed portions of said resistive heating layer;
- a protective layer of silicon carbide of a selected thickness in a range of 3250 A to 5000 A overlying said protective layer of silicon nitride;
- and a protective layer of tantalum of a selected thickness overlying said protective layer of silicon carbide, said protective layer of tantalum having a selected thickness greater than 7500 A and no greater than about 9000 A.
Dependencies are inferred from the claim text.