Integrated thermal ink jet printhead and method of manufacture

A process for fabricating an integrated thermal ink jet and driver circuit including the steps of:

• a. providing a chosen resistive material on a printhead substrate,
• b. forming a layer of refractory metal on the surface of said resistive material and having an opening therein defining one dimension of a thermal ink jet resistor,
• c. providing a passivation layer or layers on the surface of said refractory metal and having an opening therein exposing a surface area of said refractory metal,
• d. reflowing said passivation layer or layers at a chosen elevated temperature to provide smooth contours therein which are compatible with multi-level metal integrated circuit connections, and
• e. depositing interconnect metallization in said opening to make electrical contact with said refractory metal, whereby MOS driver circuitry and the like may be fabricated on a common substrate with said thermal ink jet heater resistors in a monolithic multi-level metal integrated circuit arrangement especially well suited for multi-level metal interconnections.

An integrated circuit wherein driver circuitry and printhead resistor interconnect circuitry are fabricated on a common substrate, including:

• a. a substrate having a layer of resistive material thereon, said resistive material being selected from the group consisting of polycrystalline silicon and a refractory metal silicide,
• b. a layer of refractory metal disposed on said resistive material and having an opening therein defining one dimension of a thermal ink jet resistor, said refractory metal being selected from the group consisting of tungsten and titanium and tantalum and molybdenum,
• c. a passivation layer or layers disposed on the surface of said refractory metal and having an opening therein exposing a surface area of said refractory metal,
• d. driver interconnect metallization disposed in said opening in said passivation layer and in electrical contact with said refractory metal, whereby said interconnect metallization and said refractory metal may be formed in immediately adjacent layers in an MOS multi-level metal integrated circuit, and
• e. a metal barrier layer disposed on the surface of said passivation layer or layers and above an ink jet resistor to provide enhanced insulation from ink which is disposed above said thermal ink jet resistor, said metal barrier layer is tantalum, said interconnect metallization is aluminum, and one of said passivation layers is phosphorous doped glass.