Elastic Wave Device Wiring Connection Reliability
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Solution Overview
Problem
Conventional elastic wave devices face connection reliability issues due to increased resistance and disconnection probabilities at the transition region where the second wiring electrode transitions from the first wiring electrode to the dielectric film, often resulting in protrusions and stress at the edge of the dielectric film, which deteriorates coatability and increases disconnection risks.
Innovation Solution
An elastic wave device design featuring a substrate with an interdigital transducer electrode, a first wiring electrode with a cutout in the second region adjacent to the first region, and a second wiring electrode that crosses the first wiring electrode at different heights, where the dielectric film covers the second region but not the first region, ensuring improved connection reliability by reducing excessive thinning and stress at the edge of the dielectric film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second wiring electrode transitions from the upper surface of the first wiring electrode to the upper surface of the dielectric film, then the wiring structure is formed, but the second wiring electrode thins excessively at the transition region causing increased resistance and disconnection probability
Solution Approach 1:
A protrusion is formed on the first wiring electrode at the transition region before the second wiring electrode is deposited. This preliminary structural preparation ensures that the second wiring electrode maintains adequate thickness at the transition region, preventing excessive thinning and the associated reliability issues.
Solution Approach 2:
The first wiring electrode is designed with a localized protrusion at the specific transition region where it meets the dielectric film. This local structural modification addresses the thickness uniformity problem only where needed, without affecting other regions of the wiring electrode.
2Reliability
If the dielectric film edge protrudes due to manufacturing process, then the dielectric film is formed, but the wiring electrode experiences stress at the edge causing increased disconnection probability
Solution Approach 1:
The protrusion on the first wiring electrode is formed in advance to compensate for potential edge protrusions of the dielectric film. This preliminary action creates a buffer that reduces stress concentration at the dielectric film edge, preventing wiring electrode disconnection.
3Device complexity
If the second wiring electrode is made thin to achieve different grade crossing, then the crossing structure is achieved, but the resistance value of the wiring electrode increases
Solution Approach 1:
The protrusion on the first wiring electrode is created before depositing the second wiring electrode. This preliminary action ensures that the second wiring electrode maintains sufficient thickness even when crossing at a different grade, thereby preventing excessive resistance while achieving the required crossing structure.
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 configuration enhances the connection reliability and performance of the elastic wave device by maintaining mechanical strength and reducing conduction resistance, thereby improving the reliability of the wirings crossed at different grades.
Implementation Method 1
an interdigital transducer (IDT) electrode provided on a piezoelectric substrate
Data Source
AI summary
An elastic wave device including a substrate, an interdigital transducer (IDT) electrode provided on an upper surface of the substrate, a first wiring electrode provided on the upper surface of the substrate and connected to the IDT electrode, a dielectric film that does not cover a first region of the first wiring electrode but covers a second region of the first wiring electrode above the substrate, the first wiring electrode including a cutout in the second region, and a second wiring electrode that covers an upper surface of the first wiring electrode in the first region and an upper surface of the dielectric film in the second region above the substrate.