Liquid Ejection Head Carbon Stop Layer for Precise Ink Ports
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Solution Overview
Problem
Existing liquid ejection heads face issues with ink compatibility due to the dissolution of silicon and silicon monoxide materials, leading to ejection port shape and dimension changes, and complex manufacturing processes involving complete coating with oxide-based metal films.
Innovation Solution
A manufacturing method for a liquid ejection head that forms a silicon-based film layer including carbon, laminates a silicon substrate onto this layer, and uses it as a stop layer for precise processing to form ejection ports, utilizing the carbon film's high resistance to ink and etching, thereby maintaining ejection port integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a silicon substrate coated with SiO2 film is used as an ejection port forming member, then the manufacturing process can be simplified, but the ink dissolves the silicon and SiO2 materials causing ejection port shape and dimension changes
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of a silicon substrate, SiO2 film, and Ta2O5 film. This composite structure combines the ease of manufacturing with silicon-based materials while adding the ink resistance properties of tantalum pentoxide, thereby preventing ink dissolution and maintaining ejection port precision.
Solution Approach 2:
The patent changes the material parameter by replacing pure silicon or simple SiO2 coating with a Ta2O5-coated structure. This parameter change (material composition) fundamentally alters the chemical resistance properties while maintaining the manufacturing advantages of silicon substrates, preventing ink from dissolving the ejection port materials.
2Reliability
If the entire ejection port forming member is coated with oxide-based metal film, then ink resistance is improved, but the manufacturing process becomes complicated
Solution Approach 1:
The patent applies local quality by coating only the specific regions where ink contact occurs (the ejection port areas) with Ta2O5 film, rather than coating the entire substrate uniformly. This localized approach provides ink resistance exactly where needed while minimizing the complexity of the manufacturing process.
Solution Approach 2:
The manufacturing process is segmented into distinct steps: forming the silicon substrate, depositing the SiO2 film, and then selectively coating with Ta2O5. This segmentation allows each layer to be optimized independently, achieving ink resistance without requiring a completely complex manufacturing process.
3Reliability
If conventional coating methods are used to protect the silicon substrate, then ink resistance is achieved, but the ejection port shape precision deteriorates due to complete coating
Solution Approach 1:
The patent implements local quality by ensuring that the Ta2O5 film is applied specifically to regions where ink contact occurs, maintaining precise ejection port shapes. The selective coating approach prevents ink from dissolving materials only at the critical interfaces, preserving the overall shape precision of the ejection ports.
Solution Approach 2:
The multi-layer composite structure (silicon substrate + SiO2 film + Ta2O5 film) provides both ink resistance and shape precision. The Ta2O5 layer acts as a protective barrier at the ink interface while the underlying silicon and SiO2 layers maintain the structural integrity and precise geometry of the ejection ports.
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 ensures precise ejection port shape and dimensions, reduces manufacturing complexity, and maintains good liquid ejection performance by using a carbon-containing film layer as an etching stop, providing resistance to ink and other substances.
Implementation Method 1
processing the silicon substrate bonded to the film layer using the film layer as a stop layer and forming a lower hole portion
Implementation Method 2
the use of such ink may dissolve silicon (Si) and silicon monoxide (SiO), which are common materials for ejection port forming members... the carbon film's high resistance to ink and etching
Implementation Method 3
laminating a silicon substrate on the film layer formed on the one surface of the base substrate and bonding the silicon substrate to the film layer
Data Source
AI summary
A method for manufacturing an element substrate of a liquid ejection head, the method includes forming a silicon-based film layer including carbon on one surface of a base substrate, laminating a silicon substrate on the film layer formed on the one surface of the base substrate and bonding the silicon substrate to the film layer, processing the silicon substrate bonded to the film layer using the film layer as a stop layer and forming a lower hole portion, processing the base substrate using the film layer as the stop layer and removing the base substrate to expose the film layer, and forming an opening portion communicating with the lower hole portion in the exposed film layer.