Amorphous Metal Passivation for Inkjet Printhead Energy Reduction
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Solution Overview
Problem
Forming very thin, robust, and reliable passivation structures for inkjet printheads is challenging, particularly for longer, thinner printhead dies, as polycrystalline tantalum linings are prone to oxidation and mechanical failures due to grain boundaries, which affect power efficiency and cost.
Innovation Solution
A new printhead structure combines an amorphous metal with multiple insulators, including a thicker PECVD insulator, a thinner ALD insulator, and an amorphous metal layer, which reduces the overall thickness while providing robust and reliable passivation, improving power efficiency and mechanical robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycrystalline tantalum lining is used for passivation structure, then chemical resistance and mechanical resistance are improved, but oxidation resistance and reliability deteriorate due to grain boundaries
Solution Approach 1:
The patent changes the structural parameter of the metal layer from polycrystalline to amorphous state. This eliminates grain boundaries while maintaining mechanical strength, and simultaneously improves oxidation resistance by providing a uniform structure without preferential oxidation paths along grain boundaries.
Solution Approach 2:
The patent creates a composite passivation structure combining amorphous metal layer with insulator layers. The amorphous metal provides mechanical strength and chemical resistance, while the insulator layers provide electrical isolation and additional protection, creating a synergistic multi-layer system.
2Use of energy by moving object
If passivation structure thickness is reduced to improve power efficiency, then energy consumption decreases, but mechanical robustness and reliability worsen
Solution Approach 1:
The patent changes the material structure from polycrystalline to amorphous, enabling thinner passivation structures. The amorphous structure provides superior mechanical properties and oxidation resistance per unit thickness, allowing reduction of overall passivation thickness while maintaining or improving reliability.
Solution Approach 2:
The patent uses a multi-layer composite structure with amorphous metal and insulator layers. This composite approach allows optimization of each layer's thickness for its specific function, achieving overall thinner passivation while maintaining mechanical robustness through the combined properties of different materials.
3Productivity
If thinner printhead dies are used to improve productivity, then manufacturing efficiency increases, but passivation reliability and mechanical stability worsen
Solution Approach 1:
The patent changes the metal layer structure to amorphous, which provides superior mechanical properties and oxidation resistance at reduced thickness. This enables reliable passivation on thinner printhead dies by providing a material structure that maintains integrity and protection capabilities at smaller dimensions.
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 multi-layer insulator and amorphous metal combination results in a 25% reduction in turn-on energy consumption and enhanced mechanical stability, making the passivation structure more efficient and reliable, even for longer, thinner printheads.
Implementation Method 1
protect the underlying insulators and the ejector elements against cavitation damage
Implementation Method 2
a first, thicker insulator covering the ejector element and formed by PECVD (plasma enhance chemical vapor deposition)
Implementation Method 3
Oxide growth in crystalline materials usually follows these grain boundaries, and consumption by oxidation is one failure mode of a polycrystalline tantalum layer
Data Source
AI summary
In one example, a printhead structure includes an ejector element, a multi-layer insulator covering the ejector element, and an amorphous metal on the insulator.