US 6,644,786 B1 · Method of manufacturing a thermally actuated liquid control device

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.

Claims42

Dependent claims

A method for manufacturing a thermal actuator for a micro-electromechanical device comprising the steps of:

forming a bottom layer of a bottom material on a substrate composed of a substrate material;
removing the bottom material in a bottom layer pattern wherein a moveable area located between opposing free edges remains on the substrate;
forming a deflector layer of a deflector material over the bottom layer;
removing the deflector material in a deflector layer pattern wherein the deflector material does not overlap the free edges of the bottom layer material;
and
removing the substrate material beneath the moveable area so that the free edges of the bottom layer are released from the substrate.

3 more elements

A method for manufacturing a liquid control device having a thermal actuator which moves against a working liquid contained in a liquid chamber having an inlet and an outlet comprising the steps of:

forming on a substrate having a flat surface and composed of a substrate material, a thermal actuator having a moveable area located between opposing actuator free edges wherein the substrate material remains exposed in a free edge area adjacent the actuator free edges,
conforming a sacrificial layer of a sacrificial material over the thermal actuator and substrate in sufficient thickness to result in a planar sacrificial layer surface parallel to the flat surface,
removing the sacrificial material in a sacrificial layer pattern wherein sacrificial material remains in a liquid chamber area which includes the moveable area of the thermal actuator and the free edge area,
conforming a structure layer of a structure material over the sacrificial layer;
removing the structure material in a structure layer pattern wherein sacrificial material is exposed via at least one structure opening in liquid chamber areas,
removing exposed sacrificial material from the liquid chamber area;
removing the substrate material beneath the moveable area and free edge area so that the free edges of the thermal actuator are released from the substrate allowing the thermal actuator to move in the liquid chamber and liquid to enter the liquid chamber through the substrate and around the thermal actuator.

4 more elements

Dependencies are inferred from the claim text.

Method of manufacturing a thermally actuated liquid control device

Life of this patent

Method of manufacturing a thermally actuated liquid control device

Life of this patent

Abstract

Claims42