Liquid Discharge Head Adhesion via Natural Oxide Film
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Solution Overview
Problem
The adhesion between the chamber substrate and the surface treatment film in liquid discharge heads is poor, leading to initial failure and reliability issues, with contaminants like carbon and fluorine inhibiting siloxane bond formation and causing film peeling.
Innovation Solution
A natural oxide film with a thickness of 2 nm or more is formed on the channel forming member, and a surface treatment film is applied on top, with carbon and fluorine content at 5 atomic % or less at the interface, using methods like O2 plasma processing and atomic layer deposition to enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface treatment film is formed on a chamber substrate made of single-crystal silicon, then the liquid discharge head can be manufactured, but the adhesion between the chamber substrate and the surface treatment film is poor, causing film peeling and reliability failures
Solution Approach 1:
A natural oxide film is formed on the outermost surface of the channel forming member before forming the surface treatment film. This preliminary oxidation creates a clean, contaminant-free surface that promotes strong adhesion between the chamber substrate and the subsequent surface treatment film, preventing film peeling during bonding and operation.
Solution Approach 2:
The oxidation state of the silicon surface is changed by forming a natural oxide film. This parameter change from metallic silicon to oxidized silicon surface creates a chemically active interface that enhances bonding strength and eliminates contaminants like carbon and fluorine that would otherwise inhibit adhesion.
2Reliability
If heat cycle tests are performed to select conforming products, then product quality can be ensured, but manufacturing time and cost increase
Solution Approach 1:
The natural oxide film is formed in advance during the manufacturing process, ensuring strong adhesion before final assembly. This preliminary surface preparation eliminates the need for subsequent heat cycle testing to verify adhesion quality, as the oxide film guarantees reliable bonding from the start, thereby reducing manufacturing time while maintaining product quality.
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
This approach improves the adhesion between the channel forming member and the surface treatment film, reducing defects like film peeling and enhancing the reliability and quality of the liquid discharge head.
Implementation Method 1
O2 plasma processing
Implementation Method 2
atomic layer deposition
Implementation Method 3
natural oxide film
Data Source
AI summary
A liquid discharge head includes a channel forming member made of silicon, the channel forming member including a plurality of liquid channels, a natural oxide film having a film thickness of 2 nm or more on an outermost surface of the plurality of liquid channels of the channel forming member, and a surface treatment film on the natural oxide film to contact the natural oxide film. Each of a carbon content and a fluorine content in an interface between the natural oxide film and the surface treatment film is 5 atomic % or less.