Liquid Ejection Head Alignment via Sacrificial Layer Mold
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Solution Overview
Problem
The accuracy of positional alignment between the protecting layer and the flow path forming member in liquid ejection heads is a challenge, leading to issues such as exposed substrate areas without protection, altered liquid flow resistance, residue accumulation at ejection ports, weak adhesion between layers, and damage during removal of protective members.
Innovation Solution
A method involving a protecting layer forming step, sacrificial layer forming step, patterning step, and flow path forming step, where the protecting layer is formed only on exposed substrate areas, and a sacrificial layer is used as a mold for the flow path, improving alignment accuracy and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protecting layer is formed on the entire surface of the substrate and then patterned, then the substrate is protected from liquid, but the positional alignment accuracy between the protecting layer and the flow path forming member deteriorates
Solution Approach 1:
The protecting layer is formed on the substrate surface before the flow path forming member is positioned. This preliminary formation allows the protecting layer to serve as a reference for subsequent alignment operations, ensuring that when the flow path forming member is later placed, the positional relationship can be accurately controlled based on the already-formed protecting layer pattern
Solution Approach 2:
The protecting layer formation process is divided into separate stages: first forming the protecting layer on the substrate, then patterning it, and finally using it as a reference for flow path forming member alignment. This segmentation allows each step to be optimized independently, maintaining both protection reliability and alignment precision
2Ease of manufacture
If the flow path forming member and patterned protecting layer are positionally misaligned, then the manufacturing process is simpler, but the quality of the liquid ejection head deteriorates due to exposed substrate areas
Solution Approach 1:
The patterned protecting layer serves as an intermediary reference element between the substrate and the flow path forming member. By using the protecting layer pattern as an alignment reference, the system achieves high positional accuracy without requiring complex direct alignment mechanisms, thus maintaining ease of manufacture while improving precision
3Manufacturing precision
If a protecting layer is formed only on exposed substrate areas using a sacrificial layer mold, then the positional alignment accuracy is improved, but the device complexity increases
Solution Approach 1:
The sacrificial layer is formed using the protecting layer pattern itself as a mask, allowing the protecting layer to define its own boundary conditions for the sacrificial layer formation. This self-service approach ensures automatic positional alignment between the protecting layer and the resulting flow path, achieving high precision without adding complex external alignment devices
Solution Approach 2:
The sacrificial layer is temporarily introduced as a mold material, used to form the flow path, and then removed. This temporary element enables precise flow path formation aligned with the protecting layer without permanently adding complexity to the final device structure, as the sacrificial layer is discarded after serving its molding purpose
Data Source
AI summary
A liquid ejection head is manufactured by covering a mold material arranged on a patterned protecting layer on a substrate and subsequently removing the mold material to produce a flow path. A sacrificial layer employed as the mold material operates as mask for patterning the protecting layer.