Quartz Vibrating Arm Etching to Reduce Sidewall Stepped Sections
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Solution Overview
Problem
The existing method for manufacturing vibrator devices using dry etching on both surfaces of a piezoelectric substrate can lead to the formation of stepped sections at the side surfaces of the vibrating arms, causing unwanted vibrations, cracking, and chipping when impact is applied.
Innovation Solution
A method involving a preparation step for a quartz crystal substrate, followed by first and second dry etching steps from opposite surfaces to form grooves and part of the outer shapes of the vibrating arms, and a subsequent wet etching step to reduce the size of stepped sections at the side surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching is performed on both front and rear surfaces of the substrate, then grooves and outer shapes of vibrating arms are formed at once, but stepped sections are undesirably formed at the side surface due to positional shift between photoresist films
Solution Approach 1:
The patent divides the etching process into two separate stages: first forming grooves by dry etching from one surface, then forming outer shapes by dry etching from the other surface. This segmentation eliminates the positional shift problem that occurs when attempting to form both features simultaneously, as each etching step uses its own photoresist film applied to a specific surface.
Solution Approach 2:
The patent utilizes the third dimension (depth/thickness of the substrate) to resolve the positioning conflict. By performing groove formation and outer shape formation as separate sequential steps rather than simultaneous operations, the patent eliminates the need for precise alignment of photoresist films on opposite surfaces, thereby avoiding stepped sections.
2Ease of manufacture
If stepped sections are formed at the side surface of vibrating arms, then manufacturing is simplified, but unwanted vibration and damage such as cracking and chipping occur when impact acts on the device
Solution Approach 1:
The patent segments the manufacturing process into distinct steps: groove formation followed by outer shape formation. This prevents the creation of stepped sections that would compromise structural integrity, thereby eliminating the source of cracking and chipping while maintaining manufacturing efficiency through the use of dry etching for both features.
Solution Approach 2:
The patent performs groove formation as a preliminary step before forming outer shapes. By establishing the groove structure first and then adding the outer shape features in a subsequent step, the patent ensures that the final structure has uniform side surfaces that resist impact-induced damage, while still benefiting from the efficiency of dry etching throughout the process.
3Manufacturing precision
If photoresist films are formed on both surfaces with high precision alignment, then stepped sections are minimized, but manufacturing complexity and time increase
Solution Approach 1:
The patent segments the manufacturing process so that groove formation and outer shape formation are performed in separate steps, each requiring only a single photoresist film application and alignment operation. This eliminates the need for complex dual-surface alignment, reducing both manufacturing complexity and time while achieving high precision results.
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
The proposed method effectively reduces the size of stepped sections, thereby minimizing unwanted vibrations and damage to the vibrator device when subjected to impact, while maintaining the desired frequency and vibration characteristics.
Implementation Method 1
a first dry etching step of dry-etching the quartz crystal substrate from a side facing the first surface to form the first grooves and part of outer shapes of the first vibrating arm and the second vibrating arm, a second dry etching step of dry-etching the quartz crystal substrate from a side facing the second surface
Implementation Method 2
a wet etching step of wet-etching the side surfaces of the first and second vibrating arms
Data Source
AI summary
A method for manufacturing a vibrator device includes a first dry etching step of dry-etching a quartz crystal substrate having a first surface and a second surface from the side facing the first surface to form first grooves and part of the outer shapes of a first vibrating arm and a second vibrating arm, a second dry etching step of dry-etching the quartz crystal substrate from the side facing the second surface to form second grooves and part of the outer shapes of the first vibrating arm and the second vibrating arm, and thereafter, a wet etching step of wet-etching the side surfaces of the first vibrating arm and the second vibrating arm.