Fluid-Ejection Device Wafer Bonding Resonance Optimization
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Solution Overview
Problem
The presence of a feeding channel in fluid-ejection devices can cause deterioration of the resonance frequency and reduce the velocity of fluid ejection, leading to inefficiencies in printing and other applications.
Innovation Solution
A fluid-ejection device is manufactured using piezoelectric technology by bonding three wafers, with the nozzle formation on the third wafer prior to coupling, incorporating a hydrophilic region to enhance wettability and optimize fluid flow, and reducing the thickness of the substrate to improve handling and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a feeding channel is added to enable fluid transport from chamber to nozzle, then fluid delivery function is improved, but resonance frequency deteriorates and ejection velocity is reduced
Solution Approach 1:
The patent removes the feeding channel from the device structure, extracting the harmful element that caused resonance frequency deterioration and reduced ejection velocity, while maintaining fluid delivery through alternative means
2Ease of manufacture
If wafer thickness is increased to enable proper handling during bonding, then ease of manufacture is improved, but device thickness increases and handling precision may be affected
Solution Approach 1:
The patent changes the thickness parameter of the wafer to an optimized value that balances handling ease during bonding with final device thickness requirements, achieving both manufacturability and compact form factor
3Strength
If multiple wafers are coupled together to form the device, then structural integrity is improved, but manufacturing complexity and alignment precision requirements increase
Solution Approach 1:
The patent merges multiple wafers into a single integrated structure through coupling, achieving structural integrity while reducing the number of separate components and simplifying the overall manufacturing process
4Manufacturing precision
If nozzle formation is performed after wafer coupling, then manufacturing precision is improved, but device thickness increases due to additional structural layers
Solution Approach 1:
The patent performs nozzle formation on the third wafer before coupling it to the other wafers, executing the precision-critical operation in advance when the wafer is still accessible and can be properly processed, avoiding the need for additional thick structural layers
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 optimizes the resonance frequency and increases the velocity of fluid ejection, reduces manufacturing costs, and minimizes misalignment risks while maintaining high wettability characteristics.
Implementation Method 1
a first wafer (2) comprising a substrate (11) and at least one piezoelectric actuator (3), which is designed to be governed for generating a deflection of a membrane (7)
Implementation Method 2
incorporating a hydrophilic region to enhance wettability and optimize fluid flow
Data Source
AI summary
A method for manufacturing a device for ejecting a fluid, including the steps of: forming, in a first semiconductor wafer that houses a nozzle of the ejection device, a first structural layer; removing selective portions of the first structural layer to form a first portion of a chamber for containing the fluid; removing, in a second semiconductor wafer that houses an actuator of the ejection device, selective portions of a second structural layer to form a second portion of the chamber; and coupling together the first and second semiconductor wafers so that the first portion directly faces the second portion, thus forming the chamber. The first portion defines a part of volume of the chamber that is larger than a respective part of volume of the chamber defined by the second portion.