MEMS Device Bonding Region Width for Adhesive Particle Distribution
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Solution Overview
Problem
In MEMS devices and liquid ejecting heads, the uneven distribution of solid particles in adhesives during bonding reduces the bonding strength between substrates, leading to unreliable connections.
Innovation Solution
Designing the bonding region with a width wider than the maximum particle diameter of solid particles in the adhesive, allowing for uniform distribution and enhanced bonding strength by ensuring the adhesive spreads evenly, thereby improving the electrical and mechanical connections between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive with solid particles is used for bonding substrates, then bonding strength is improved, but if solid particles are unevenly distributed, bonding strength is lowered
Solution Approach 1:
The patent changes the geometric parameter of the bonding region (width) to be larger than the particle diameter, which transforms the distribution problem into a spatial accommodation problem. This parameter change ensures that particles can be uniformly distributed without aggregation, resolving the contradiction between achieving strong bonding and maintaining manufacturing precision.
Solution Approach 2:
The patent introduces a dimensional consideration by comparing the width of the bonding region with the diameter of solid particles. By ensuring the bonding region width exceeds particle diameter, the patent creates sufficient spatial dimension for particles to distribute uniformly, thereby resolving the distribution uniformity issue while maintaining bonding strength.
2Manufacturing precision
If bonding region width is increased to accommodate solid particles, then particle distribution uniformity is improved, but bonding region area is increased
Solution Approach 1:
The patent optimizes the width parameter of the bonding region to be just sufficient (larger than particle diameter) rather than excessively large. This parameter optimization achieves uniform particle distribution while minimizing the bonding region area, thus resolving the contradiction between manufacturing precision and area consumption.
3Strength
If adhesive contains solid particles for enhanced bonding, then bonding strength is improved, but electrical connection reliability is reduced due to particle aggregation
Solution Approach 1:
The patent changes the bonding region width parameter to prevent particle aggregation, which simultaneously achieves strong bonding and reliable electrical connections. By ensuring sufficient space for particle distribution, the patent eliminates the harmful aggregation effect while maintaining the beneficial bonding strength enhancement.
Solution Approach 2:
The patent converts the potential harm of solid particles (aggregation causing poor electrical connection) into a benefit by providing sufficient space for their uniform distribution. The same solid particles that could cause reliability issues become beneficial for bonding strength when properly distributed, resolving the contradiction between strength and reliability.
Data Source
AI summary
In an MEMS device, in a Z direction that is a direction in which a first core portion, a plurality of first bump wiring, and a plurality of first individual wiring are laminated, a width between the first core portion and a wiring substrate is wider than a maximum particle diameter of solid particles contained in an adhesive, and a width between a first wiring and a second wiring and a width between a third wiring and a fourth wiring are wider than the maximum particle diameter of the solid particles.