Liquid Ejection Head Substrate Carbon-Silicon Barrier Protection
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Solution Overview
Problem
The reduction in orifice plate thickness in ink-jet recording apparatuses makes it difficult to protect the electrode pad with a resin-based adhesiveness improving layer, leading to challenges in preventing side etching during wet processing and compromising electrical reliability.
Innovation Solution
A liquid ejection head substrate with a barrier metal layer and a bonding layer, where the end side surface of the barrier metal layer is covered with a silicon-based film containing carbon, providing protection against side etching and enhancing electrical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the orifice plate is reduced to improve image quality and enable smaller liquid droplet ejection, then the required precision of flattening increases, making it difficult to protect the electrode pad with a resin-based adhesiveness improving layer
Solution Approach 1:
The patent changes the material parameter of the protective film from resin-based to silicon-based containing carbon. This material substitution allows the film to provide adequate protection with reduced thickness, meeting the stringent flattening precision requirements while maintaining electrical reliability through the barrier metal layer protection.
Solution Approach 2:
The patent employs a composite structure consisting of a barrier metal layer and a silicon-based film containing carbon. This composite material system provides both the mechanical protection needed for side etching prevention and the electrical reliability required for thin orifice plate configurations, resolving the contradiction between precision and reliability.
2Manufacturing precision
If protection using a resin-based adhesiveness improving layer is eliminated to achieve better flattening precision, then manufacturing precision improves, but side etching of the barrier metal layer occurs during wet processing
Solution Approach 1:
The patent changes the chemical composition parameter of the protective film from resin-based to silicon-based containing carbon. This material substitution provides resistance against side etching in wet processing while maintaining the thin profile needed for high flattening precision, eliminating the need for a separate adhesiveness improving layer.
Solution Approach 2:
The silicon-based film containing carbon serves as a temporary protective layer during manufacturing that can be removed or integrated into the final structure. It provides the necessary protection against side etching during wet processing steps and then fulfills its protective function, allowing the process to proceed without permanent complex protective structures.
3Manufacturing precision
If the amount of adhesiveness improving layer is reduced to meet flattening precision requirements, then manufacturing precision improves, but the electrode pad can no longer be protected
Solution Approach 1:
The patent fundamentally changes the material parameter of the protective film from resin-based to silicon-based containing carbon. This material substitution enables the film to provide adequate protection with significantly reduced thickness, meeting the stringent flattening precision requirements while simultaneously preventing side etching through the barrier metal layer protection.
Solution Approach 2:
The silicon-based film containing carbon performs multiple functions simultaneously: it provides protection against side etching, maintains electrical reliability, and satisfies flattening precision requirements. This multi-functional protective layer eliminates the need for separate adhesiveness improving layers, resolving the contradiction between precision and protection.
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 silicon-based film with carbon effectively protects the barrier metal layer from side etching during manufacturing and improves the durability and reliability of the ink-jet recording head by preventing corrosion and maintaining bonding properties.
Implementation Method 1
an end side surface of the barrier metal layer is covered with a silicon-based film containing carbon
Data Source
AI summary
Provided is a liquid ejection head substrate including: a substrate; a liquid ejection element that generates liquid ejection energy on the substrate; and an electrode pad that is electrically connected to the liquid ejection element, in which the electrode pad includes a barrier metal layer and a bonding layer on the barrier metal layer, and an end side surface of the barrier metal layer is covered with a silicon-based film containing carbon.