MEMS Eutectic Connection Layout for Stable Resonator Wiring
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Solution Overview
Problem
In MEMS devices, metal diffusion along connection wiring from the eutectic bonding between substrates can lead to unstable electrical connections and affect the underlying resonator element, causing a decrease in metal amount and disrupting eutectic reactions.
Innovation Solution
A resonance device with a connection wiring width smaller than the connection portion, formed of a eutectic alloy of first and second metals, reduces metal diffusion by minimizing the area for eutectic alloy metal to diffuse, thereby stabilizing the electrical connection and preventing metal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If eutectic bonding is used to bond the upper substrate and lower substrate, then bonding strength is improved, but metal diffusion along the connection wiring occurs causing unstable electrical connections
Solution Approach 1:
The connection portion is designed with a larger width than the connection wiring, creating a localized expansion area. This local quality change provides a broader bonding interface for eutectic bonding while restricting metal diffusion to a confined region, preventing diffusion along the narrower connection wiring path.
Solution Approach 2:
The connection portion introduces a width dimension that is larger than the connection wiring width, creating a two-dimensional expansion in the bonding area. This dimensional change provides sufficient bonding area for strong eutectic bonding while the boundaries of the connection portion confine metal diffusion laterally.
2Device complexity
If the connection portion has the same width as the connection wiring, then manufacturing complexity is reduced, but metal diffusion affects the element causing performance degradation
Solution Approach 1:
The connection portion is designed with a larger width than the connection wiring, creating a localized expansion area. This local quality change provides a broader bonding interface for eutectic bonding while restricting metal diffusion to a confined region, preventing diffusion along the narrower connection wiring path.
3Reliability
If the connection portion width is increased, then eutectic bonding reliability is improved, but device area increases
Solution Approach 1:
The connection portion is designed with a larger width than the connection wiring, creating a localized expansion area. This local quality change provides a broader bonding interface for eutectic bonding while restricting metal diffusion to a confined region, preventing diffusion along the narrower connection wiring path.
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 design effectively reduces metal diffusion along the connection wiring, maintaining the integrity of the eutectic reaction and ensuring stable electrical connections in the MEMS device.
Implementation Method 1
a connection portion electrically connected to the connection wiring and formed of a eutectic alloy of a first metal and a second metal
Data Source
AI summary
A MEMS device that includes a substrate including an element and a connection wiring electrically connected to the element, and a connection portion electrically connected to the connection wiring. The connection portion is formed of a eutectic alloy of a first metal and a second metal. A line width of the connection wiring is smaller than a width of the connection portion when a main surface of the substrate is viewed in a plan view.