Method of forming thermal bend actuator with connector posts connected to drive circuitry
View Patent ↗A method of forming a thermal bend actuator in an inkjet nozzle assembly. The method includes: depositing sidewalls and a roof layer to define a nozzle chamber; defining first and second vias in one sidewall to reveal first and second electrodes; filling the vias with a conductive material using electroless plating to provide first and second connector posts; depositing an active beam material onto the roof layer; etching the active beam material to define a planar active beam member comprising a bent or serpentine beam element; and etching the roof layer to define the thermal bend actuator.
1. A method of forming a thermal bend actuator in an inkjet nozzle assembly, said method comprising the steps of:
(a) providing a substrate having a layer of drive circuitry, said drive circuitry including first and second electrodes for connection to the thermal bend actuator;
(b) depositing sidewalls and a roof layer to define a nozzle chamber, wherein a first sidewall is deposited over said first and second electrodes;
(c) defining first and second vias in said first sidewall, said vias revealing said first and second electrodes;
(d) filling said first and second vias with a conductive material using electroless plating to provide first and second connector posts, said first and second connector posts being adjacent each other;
(e) depositing an active beam material onto said roof layer such that said active beam material extends from said first and second connector posts in a plane perpendicular to said posts;
(f) etching said active beam material to define a planar active beam member comprising a bent or serpentine beam element, said beam element having a first end positioned over said first connector post and a second end positioned over said second connector post; and
(g) etching said roof layer to define the thermal bend actuator, said thermal bend actuator being moveable towards said substrate upon actuation.
2. The method of claim 1 , wherein a distance between said actuator and said electrode is at least 5 microns.
3. The method of claim 1 , wherein said layer of drive circuitry is a CMOS layer of a silicon substrate.
4. The method of claim 1 , wherein said sidewalls are comprised of silicon dioxide.
5. The method of claim 1 , wherein said vias have sidewalls perpendicular to a face of said substrate.
6. The method of claim 1 , wherein said vias have a minimum cross-sectional dimension of 1 micron or greater.
7. The method of claim 1 , wherein said conductive material is a metal.
8. The method of claim 1 , wherein said conductive material is copper.
9. The method of claim 1 , comprising the further step of:
depositing a catalyst layer on a base of said vias prior to said electroless plating.
10. The method of claim 9 , wherein said catalyst is palladium.
11. The method of claim 1 , wherein said conductive material is planarized by chemical mechanical planarization prior to forming said actuator.
12. The method of claim 1 , further comprising the step of:
depositing a first metal pad over a top of said first and second connector posts prior to deposition of said active beam material, said first metal pad being configured to facilitate current flow between the connector posts and the active beam member.
13. The method of claim 12 , further comprising the step of:
depositing one or more second metal pads onto said passive beam material prior to deposition of said active beam material, said second metal pad being positioned to facilitate current flow in bend regions of said beam element.
14. The method of claim 1 , wherein said first and second connectors posts extend linearly from said electrodes.