Inkjet Nozzle Connector Posts for Electrical Loss Reduction
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Solution Overview
Problem
Inkjet nozzle designs face significant electrical losses due to sub-optimal actuator material conductivity and tortuous current paths, particularly in mechanical thermal bend-actuated nozzles, which exacerbate energy inefficiencies and complicate MEMS fabrication processes.
Innovation Solution
A method is developed to form electrical connections between electrodes and actuators using copper connector posts formed through electroless plating, with perpendicular sidewalls and minimal bends, reducing current losses and enhancing structural integrity by eliminating the need for PECVD deposition, resulting in a planar ink ejection face and improved nozzle assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional PECVD deposition methods are used to form electrical connections, then the current path becomes tortuous with multiple bends, but this increases electrical losses and reduces manufacturing precision
Solution Approach 1:
Instead of forming the current path by depositing material along a tortuous route, the invention inverts the approach by etching perpendicular vias through the substrate and filling them with highly conductive copper material. This creates a straight, minimal-bend current path from the electrode to the actuator, dramatically reducing electrical losses while simplifying the current path geometry.
Solution Approach 2:
The invention changes the material parameter by using electroless plating to deposit copper with superior electrical conductivity compared to traditional PECVD deposited materials. This parameter change in material conductivity directly reduces electrical losses in the current path while maintaining structural integrity.
2Manufacturing precision
If perpendicular via walls are formed, then manufacturing precision is improved, but this increases device complexity
Solution Approach 1:
The invention applies preliminary action by first depositing a sacrificial layer and forming the via pattern before etching. This preliminary structuring enables the formation of perpendicular via walls through standard anisotropic etching processes, achieving high manufacturing precision without excessive complexity in the overall fabrication sequence.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly reduces electrical losses and enhances the structural integrity of inkjet nozzle assemblies by providing a direct, highly conductive path between electrodes and actuators, allowing for more efficient ink ejection and improved compatibility with standard MEMS fabrication processes.
Implementation Method 1
copper connector posts formed through electroless plating
Implementation Method 2
Thermal bend actuation generally means bend movement generated by thermal expansion of one material, having a current passing therethough, relative to another material
Data Source
AI summary
A printhead integrated circuit is provided. The printhead integrated circuit comprises a silicon substrate having a plurality of inkjet nozzles assemblies formed on a surface of the substrate. The substrate has drive circuitry for supplying power to the nozzle assemblies. Each nozzle assembly comprises: a nozzle chamber for containing ink, the nozzle chamber having a nozzle opening defined therein; an actuator for ejecting ink through the nozzle opening; a pair of electrodes positioned at the surface of the substrate, the electrodes being electrically connected to the drive circuitry; and a pair of connector posts, each connector post electrically connecting a respective electrode to the actuator. Each connector post extends linearly from a respective electrode to the actuator.