Quartz Vibrator Element Etching With Dual-Rate Protective Films
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Solution Overview
Problem
Existing manufacturing methods for tuning fork-type vibrator elements face challenges in collectively forming the outer shape and grooves without complexity, leading to potential vibration issues and restricted design freedom due to separate etching steps or reliance on the micro-loading effect.
Innovation Solution
A method involving the use of protective films with different etching rates for dry etching, allowing simultaneous formation of grooves and outer shapes without micro-loading effects, thereby enhancing design freedom and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate wet etching and dry etching steps are used to form the outer shape and grooves respectively, then the manufacturing process can be simplified, but the grooves tend to be displaced relative to the outer shape and unnecessary vibration occurs
Solution Approach 1:
The patent combines the formation of the outer shape and grooves into a single dry etching step by using a patterned protective film that exposes both the outer shape regions and groove regions simultaneously. This merging of operations eliminates the displacement problem between grooves and outer shape while maintaining manufacturing simplicity.
2Manufacturing precision
If the outer shape and grooves are collectively formed using the micro-loading effect in dry etching, then groove displacement is avoided, but the settings of dimensions including widths of vibrating arms and widths and depths of grooves are restricted and design freedom is reduced
Solution Approach 1:
The patent applies local quality by using a patterned protective film with different etching resistance properties in different regions. The protective film is formed with specific thickness variations corresponding to groove formation regions versus outer shape formation regions, allowing independent dimension control of each feature while maintaining precise relative positioning through the unified etching process.
3Device complexity
If a single dry etching step is used to form both outer shape and grooves, then manufacturing complexity is reduced, but control over groove and arm dimensions becomes more difficult
Solution Approach 1:
The patent employs preliminary action by pre-forming a protective film with specifically controlled thickness distribution before the dry etching step. The protective film thickness is predetermined to be greater in groove formation regions than in outer shape formation regions, allowing precise dimensional control of both grooves and outer shape to be established in advance before the actual etching occurs.
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 enables precise control over groove and arm dimensions, reduces unnecessary vibrations, and increases the manufacturing accuracy and cost-effectiveness by integrating groove and outer shape formation in a single dry etching step.
Implementation Method 1
a first dry etching step of dry etching the quartz crystal substrate from the first substrate surface side via the first protective film and the second protective film and forming the first surface, the first grooves, and outer shapes of the first vibrating arm and the second vibrating arm
Data Source
AI summary
A manufacturing method for a vibrator element includes a preparation step of preparing a quartz crystal substrate having a first substrate surface and a second substrate surface, a first protective film formation step of forming a first protective film in first groove formation areas of the first substrate surface, a second protective film formation step of forming a second protective film in an area except the first groove formation areas of a first vibrating arm formation area and a second vibrating arm formation area of the first substrate surface, and a first dry etching step of dry etching the quartz crystal substrate from the first substrate surface side via the first protective film and the second protective film and forming a first surface, first grooves, and outer shapes of the first vibrating arm and the second vibrating arm, wherein r1>r2, where an etching rate of the first protective film is r1 and an etching rate of the second protective film is r2.