Silicon Watch Component Etching With Test Specimens for Stiffness Control
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Solution Overview
Problem
Existing manufacturing processes for watch components, such as balance springs, exhibit significant geometric variation leading to inconsistent stiffness, which affects the accuracy of watch movements, and existing methods to correct this variation are time-consuming and prone to contamination.
Innovation Solution
A manufacturing process that includes forming watch components on a silicon-based substrate using deep reactive ion etching with a photosensitive resin mask, utilizing a test specimen on the same wafer to characterize and correct dimensional deviations, allowing for quick and reproducible production of components with optimized stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deep reactive ion etching is used to manufacture watch components, then manufacturing precision is improved, but geometric dispersion increases due to substrate variations
Solution Approach 1:
The patent applies preliminary action by forming test pieces with different geometries (rectangular, L-shaped, T-shaped) on the substrate before manufacturing the actual watch components. These test pieces are used to characterize substrate properties and predict component dimensions, allowing compensation for substrate variations before the actual component fabrication occurs.
Solution Approach 2:
The patent implements feedback by measuring the actual dimensions of test pieces after etching, comparing them with target dimensions, and using this information to adjust manufacturing parameters for subsequent components. This closed-loop approach compensates for geometric dispersion caused by substrate variations.
2Measurement precision
If frequency measurement is used to determine hairspring stiffness, then measurement precision is improved, but time consumption increases significantly
Solution Approach 1:
The patent uses test pieces as simplified copies or proxies of the actual hairsprings. Instead of measuring and characterizing each individual hairspring through time-consuming frequency measurements, the test pieces are measured once per substrate batch, and their characteristics are used to predict the properties of all components made from that substrate.
Solution Approach 2:
The test pieces serve multiple functions: they characterize substrate properties, predict component dimensions, and enable stiffness determination without direct measurement of the final components. This multi-functionality reduces the overall time required for quality control.
3Measurement precision
If frequency measurement is performed to determine component characteristics, then measurement precision is improved, but risk of pollution increases
Solution Approach 1:
The patent introduces test pieces as intermediary elements that are used for measurement and characterization instead of the actual hairsprings. These test pieces are sacrificed or used exclusively for testing, protecting the valuable final components from pollution or damage during the measurement process.
4Manufacturing precision
If corrected masks with different window dimensions are used, then geometric dispersion is reduced, but device complexity increases
Solution Approach 1:
The patent changes the geometric parameters of test pieces (different shapes and dimensions) to optimize their effectiveness for characterizing various substrate properties. By varying test piece geometry rather than mask complexity, the approach achieves dimensional consistency without significantly increasing device complexity.
Data Source
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AI summary
The present invention relates to a method for manufacturing watch components (110), in which, in a silicon-based wafer (100), watch components (110) are formed according to target dimensions, as well as at least one test specimen (120) of geometry different from that of the components (110), at least one characterization parameter of the test specimen (120) representative of a characteristic of the components is determined, and from said parameter, said characteristic of the components is determined and/or it is determined whether a dimensional correction should be applied to the components (110).