Surface Acoustic Wave Apparatus Frame Lid Sealing
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Solution Overview
Problem
Conventional methods for manufacturing surface acoustic wave apparatuses face issues with degradation of electric characteristics due to etchant and etching products remaining in hollow portions, and require complex processes for forming these hollows using sacrifice layers.
Innovation Solution
A method that forms a tightly-closed space without a sacrifice layer by creating a frame member and lid on a piezoelectric substrate, using films that are patterned and cured to form a protective cover, thereby reducing the number of processes and preventing etchant residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sacrifice layer is used to form a hollow portion, then the hollow portion can be formed, but electric characteristics deteriorate due to etchant and etching products remaining in the hollow portion
Solution Approach 1:
The invention extracts and removes the harmful element (sacrifice layer) from the system. Instead of using a polysilicon sacrifice layer that requires etching and leaves residues, the patent forms the hollow portion directly by removing material and then sealing it with a protective cover, eliminating the source of etchant contamination and improving electric characteristics
Solution Approach 2:
The invention inverts the conventional approach by not using a sacrifice layer at all. Rather than forming a hollow portion through sacrifice layer deposition and subsequent removal, the patent directly creates the hollow space and seals it, reversing the traditional sequence and eliminating the harmful etching process
2Manufacturing precision
If a sacrifice layer is used to form a hollow portion, then the hollow portion can be created, but the manufacturing process becomes complex with many required steps
Solution Approach 1:
The invention extracts and eliminates the sacrifice layer from the manufacturing process. By removing this intermediate material that requires multiple processing steps (deposition, patterning, etching, cleaning), the patent simplifies the overall manufacturing process while still achieving the desired hollow portion formation
Solution Approach 2:
The patent inverts the conventional manufacturing sequence by directly forming the hollow portion and then sealing it with a protective cover, rather than using a sacrifice layer that must be deposited and subsequently removed. This reversal reduces the number of manufacturing steps and process complexity
3Volume of moving object
If the surface acoustic wave apparatus is miniaturized for surface packaging, then packaging density improves, but it becomes difficult to ensure vibration space and achieve air-tight sealing
Solution Approach 1:
The invention applies the nesting principle by integrating the protective cover directly onto the piezoelectric substrate in a wafer-level packaging structure. The protective cover is formed as an integral part of the miniaturized device, creating nested layers that provide both vibration space and air-tight sealing within a compact form factor suitable for surface mounting
Solution Approach 2:
The patent uses thin film structures for the protective cover that can conform to the miniaturized device geometry. These flexible thin films provide effective air-tight sealing and maintain the required vibration space even in highly compacted WLP-type packages, enabling reliable operation in small-size applications
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 the reliability of surface acoustic wave apparatuses by minimizing electric characteristic degradation and simplifying the manufacturing process, resulting in improved productivity and air-tight properties.
Implementation Method 1
an IDT electrode 102...formed on an upper surface of a piezoelectric substrate 101
Implementation Method 2
forming a protective cover which consists of the frame member 106 and a lid 107 that covers the formation area and composes inner wall of tightly-closed space
Data Source
AI summary
Provided is a method for manufacturing a surface acoustic wave apparatus that can reduce degradation of electric characteristics and also reduce the number of manufacturing processes. The method for manufacturing a surface acoustic wave apparatus includes the steps of: forming an IDT electrode on an upper surface of a piezoelectric substrate, forming a frame member surrounding a formation area in which the IDT electrode is formed on the piezoelectric substrate, and mounting a film-shaped lid member on the upper surface of the frame member so as to be joined to the frame member so that a protective cover, used for covering the formation area and for providing a tightly-closed space between it and the formation area, is formed.