Quartz Vibration Element Etching for Stable Groove Depth
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Solution Overview
Problem
The existing method for manufacturing vibration elements using dry etching is prone to variations in groove depth due to changes in dry etching time, affecting the vibration characteristics of the element.
Innovation Solution
A method involving a quartz crystal substrate with protective films applied on specific regions for controlled dry etching from both surfaces, ensuring the micro-loading effect maintains consistent groove depths relative to contour depths, thereby stabilizing vibration characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If dry etching time is increased to deepen the groove, then groove depth increases, but vibration characteristics vary due to excessive depth
Solution Approach 1:
The etching process is divided into two separate stages: first etching the groove to a preliminary depth, then etching the inter-arm region to a greater depth. This segmentation allows independent control of groove depth and inter-arm region depth, preventing over-etching of the groove while achieving the required inter-arm etching depth, thus maintaining consistent vibration characteristics.
Solution Approach 2:
The groove is etched to its final depth first, before etching the inter-arm region. By performing the groove etching as a preliminary action with controlled depth, the method ensures that subsequent etching of the inter-arm region does not affect the already-formed groove depth, thereby maintaining manufacturing precision.
2Manufacturing precision
If dry etching time is decreased to maintain groove depth, then groove depth remains consistent, but inter-arm region etching is insufficient
Solution Approach 1:
The etching process is divided into two separate stages: first etching the groove to a preliminary depth, then etching the inter-arm region to a greater depth. This segmentation allows independent control of groove depth and inter-arm region depth, preventing over-etching of the groove while achieving the required inter-arm etching depth, thus maintaining consistent vibration characteristics.
Solution Approach 2:
The method applies partial etching to the groove region (stopping at preliminary depth) and excessive etching to the inter-arm region (etching deeper than the groove). This selective partial and excessive action ensures the groove maintains its required depth consistency while the inter-arm region receives sufficient etching.
3Ease of manufacture
If single-sided dry etching is used to simplify the process, then manufacturing complexity decreases, but groove depth and contour shape cannot be independently controlled
Solution Approach 1:
The etching process is divided into two separate stages: first etching the groove to a preliminary depth, then etching the inter-arm region to a greater depth. This segmentation allows independent control of groove depth and inter-arm region depth, preventing over-etching of the groove while achieving the required inter-arm etching depth, thus maintaining consistent vibration characteristics.
Solution Approach 2:
The method transitions from single-sided etching to dual-sided etching, adding a new dimension to the etching process. By etching from both the first surface and the second surface of the quartz crystal substrate, the method achieves independent control of groove depth and contour shape that cannot be accomplished with single-sided etching alone.
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 reduces thermoelastic loss and enhances vibration characteristics by maintaining consistent groove depths and contour shapes, improving manufacturing accuracy and cost-effectiveness.
Implementation Method 1
a first protective film forming step of forming a first protective film on the first surface of the quartz crystal substrate, excluding first groove forming regions where the first grooves are formed and an inter-arm region located between a first vibrating arm forming region where the first vibrating arm is formed and a second vibrating arm forming region where the second vibrating arm is formed
Implementation Method 2
a first dry etching step of dry etching the quartz crystal substrate from a first surface side via the first protective film and forming the first grooves and contours of the first vibrating arm and the second vibrating arm on the first surface
Data Source
AI summary
A method for manufacturing a vibration element includes: a first dry etching step of dry etching the quartz crystal substrate from a first surface and forming first grooves and contours of a first vibrating arm and a second vibrating arm on the first surface; and a second dry etching step of dry etching the quartz crystal substrate from a second surface side and forming second grooves and contours of the first vibrating arm and the second vibrating arm on the second surface, in which Wa/Aa<1 in at least one of the first and second dry etching steps, Wa is a depth of the first and second grooves formed in the first and second dry etching steps, and Aa is a depth of the contours formed in the first and second dry etching steps.