Importance

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Abstract

Methods for manufacturing thermally actuated liquid control devices such as ink jet printheads and fluid microvalves are disclosed. Thermal actuators for a micro-electromechanical devices are manufactured by process steps of forming a bottom layer of a bottom material on a substrate having a flat surface and composed of a substrate material; and removing the bottom material in a bottom layer pattern wherein a moveable area located between opposing free edges remains on the substrate. A deflector layer of a deflector material is formed over the bottom layer and patterned so that the deflector material does not overlap the free edges of the bottom layer material. A top layer of a top material is formed over the deflector layer, the bottom layer, and the substrate and patterned so that the top material overlaps the deflector layer material but does not completely overlap the substrate material in the free edge area. A layer of a sacrificial material is conformed over the top, deflector, bottom layers and substrate in sufficient thickness to result in a planar sacrificial layer surface parallel to the flat surface of the substrate. The sacrificial material is patterned so that sacrificial material remains in movement areas and adjacent free edge areas. A structure layer of a structure material is formed over the sacrificial layer and patterned to have openings which expose the sacrificial material in movement areas. The substrate material beneath the moveable area is removed so that the free edges of the bottom layer are released from the substrate and the exposed sacrificial material is removed from the movement areas and free edge areas thereby creating a movement volume for the thermal actuator. High temperature microelectronic fabrication processes may be used for forming the bottom, deflector and top layer materials. The openings in the structure material may serve as nozzles for a liquid drop emitter or as outlet ports for a microvalve. In some preferred embodiments of the inventions, the deflector layer of the thermal actuator may be formed with an electrically resistive material, especially titanium aluminide, the bottom layer may be formed by oxidation of the substrate, and the sacrificial material may be non-photoimageable polyimide.

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First Claim