Acoustic Wave Resonance Structure Protection During Fabrication
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Solution Overview
Problem
The fabrication processes of acoustic wave devices can damage the 'air bridge' structure at the resonance region, affecting the performance of the device.
Innovation Solution
A protective layer is arranged above the surface, far away from the substrate, specifically at the overlapping region of the first and second electrode layers, to shield and protect the 'air bridge' structure during fabrication, preventing damage from fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fabrication processes (bump formation, substrate thinning, cutting) are performed to manufacture the acoustic wave device, then the device can be produced and packaged, but the 'air bridge' structure at the resonance region is damaged and performance deteriorates
Solution Approach 1:
A protective layer is formed over the resonance region before fabrication processes such as bump formation, substrate thinning, and cutting are performed. This preliminary protective action prevents damage to the air bridge structure during subsequent manufacturing steps, allowing both device production and performance preservation
Solution Approach 2:
The protective layer acts as an intermediary element between the fabrication processes and the sensitive air bridge structure. It absorbs or shields against mechanical stresses and damages from bump formation, substrate thinning, and cutting operations, thereby protecting the resonance region while enabling normal manufacturing procedures
2Reliability
If the protective layer is formed to protect the resonance region, then the air bridge structure is shielded from damage, but the fabrication process complexity increases
Solution Approach 1:
The protective layer is segmented into different regions with different thicknesses: a first thickness over the resonance region and a second thickness over other areas. This segmentation allows targeted protection where needed while minimizing additional process complexity and material usage in non-critical areas
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 solution effectively shields the 'air bridge' structure from fabrication-induced damage, thereby improving the performance and stability of the acoustic wave device by avoiding resonance region interference.
Implementation Method 1
a piezoelectric layer (3) and a second electrode layer (4) which are sequentially arranged on the substrate (1)
Data Source
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AI summary
An acoustic wave device is provided, which includes a substrate, as well as a first electrode layer, a piezoelectric layer and a second electrode layer which are sequentially arranged on the substrate. The device further includes a protective layer. The protective layer is at least arranged at a first position above the surface, far away from the substrate, of the second electrode layer. The first position is a position, corresponding to a first overlapping region, above the second electrode layer. The first overlapping region, where an active area of the acoustic wave device is located, is at least a part of a region where the first electrode layer, the second electrode layer and the piezoelectric layer are overlapped. A fabrication method for an acoustic wave device is also provided.