Film Bulk Acoustic Resonator Cavity Structure Without Sacrificial Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional film bulk acoustic resonator manufacturing methods damage device materials due to etching of sacrificial materials, affecting device reliability.
Innovation Solution
A film bulk acoustic resonator design that includes a substrate, buffer layer, first electrode layer, piezoelectric layer, and second electrode layer, with a cavity structure located between the substrate and the first electrode layer, partially in the buffer layer, eliminating the need for etching sacrificial materials by using an N-type semiconductor and a metal synergistic resistance reduction layer to form the cavity structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If etching method is used to remove sacrificial material, then cavity structure is formed, but device materials covering the sacrificial material are damaged
Solution Approach 1:
The patent extracts and removes the sacrificial material completely before forming the piezoelectric layer, eliminating the need for subsequent etching steps. This is achieved by forming a cavity structure in the buffer layer that exposes the electrode directly to air, allowing the sacrificial material to be removed without damaging other device materials.
Solution Approach 2:
The cavity structure is formed preliminarily in the buffer layer before depositing the piezoelectric layer. This preliminary action creates the necessary air interface for the electrode without requiring post-deposition etching of sacrificial materials, thereby preventing damage to device materials.
2Ease of operation
If sacrificial material is etched away, then air interface is formed for electrode operation, but other device materials are damaged to varying degrees
Solution Approach 1:
The buffer layer acts as an intermediary structure that contains the cavity. By forming the cavity within the buffer layer rather than etching through sacrificial material, the patent creates the necessary air interface for electrode operation while protecting other device materials from damage.
Solution Approach 2:
The sacrificial material is completely extracted and removed before piezoelectric layer formation, eliminating the need for harmful etching processes. The cavity structure in the buffer layer provides the air interface needed for electrode operation without requiring subsequent sacrificial material removal.
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 enhances device reliability by avoiding the damage caused by etching sacrificial materials and improves electrical resistivity and stability, while also simplifying the manufacturing process and reducing environmental pollution.
Implementation Method 1
a piezoelectric layer, a second electrode layer stacked in sequence
Data Source
AI summary
Disclosed are a film bulk acoustic resonator and a manufacturing method therefor. The film bulk acoustic resonator includes: a substrate, a buffer layer, a first electrode layer, a piezoelectric layer, a second electrode layer stacked in sequence, and a cavity structure arranged between the substrate and the first electrode layer and at least partially located in the buffer layer, where the first electrode layer includes an N-type semiconductor. The N-type semiconductor has an integrated structure and may be used as an electrode, so that the cavity structure at least partially located in the buffer layer may be formed first, and then the N-type semiconductor is arranged on the cavity structure. Thus, there is no need to etch sacrificial materials to form the cavity structure, thereby reducing probability of device reliability deterioration due to etching sacrificial materials.