Silicon Micro-Mechanical Parts with Thick Amorphous Silicon Dioxide Coating
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Solution Overview
Problem
Silicon micro-mechanical parts, such as those in watch movements, are sensitive to shocks due to their inherent mechanical weakness, which can lead to breakage and malfunction during assembly or incidental impacts.
Innovation Solution
A thermal oxidation process is used to form a thick amorphous silicon dioxide layer on the silicon parts, significantly enhancing their mechanical properties and impact resistance, while also applying an anti-friction coating for additional benefits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If silicon is used to manufacture micro-mechanical parts, then density is reduced and magnetic field sensitivity is eliminated, but impact resistance and mechanical strength deteriorate
Solution Approach 1:
The patent applies composite materials by coating the silicon micro-mechanical part with a layer of amorphous silicon oxide. This creates a composite structure where the silicon core provides low density and magnetic field insensitivity, while the silicon oxide coating provides enhanced mechanical strength and impact resistance. The combination resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent changes the physical and chemical parameters of the silicon surface through thermal oxidation, transforming it into amorphous silicon oxide with different mechanical properties. This parameter change (from crystalline silicon to amorphous silicon oxide) enhances the surface hardness and fracture toughness, thereby improving impact resistance while maintaining the bulk silicon's low density.
2Object-affected harmful factors
If silicon is used to manufacture micro-mechanical parts, then magnetic field sensitivity is eliminated, but mechanical strength deteriorates
Solution Approach 1:
The patent uses composite materials by combining silicon with amorphous silicon oxide coating. The silicon core maintains magnetic field insensitivity, while the silicon oxide layer provides enhanced mechanical strength, resolving the contradiction between magnetic field resistance and mechanical strength.
3Strength
If a thick amorphous silicon oxide layer is formed on silicon parts, then mechanical strength and impact resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The patent replaces mechanical reinforcement methods with a chemical/thermal process (thermal oxidation) to form the silicon oxide layer. This substitution of manufacturing approach simplifies the process compared to mechanical reinforcement techniques, as thermal oxidation is a well-established semiconductor fabrication process that can be precisely controlled.
Solution Approach 2:
The patent uses parameter changes (temperature, time, oxygen atmosphere) to control the thermal oxidation process, forming the desired thickness of amorphous silicon oxide layer. By precisely controlling these parameters, the manufacturing process achieves consistent results without requiring complex multi-step procedures.
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 treated silicon parts exhibit improved mechanical strength and durability, withstanding shocks and maintaining satisfactory isochronism for extended periods, as demonstrated by increased success rates in assembly and impact tests compared to untreated parts.
Implementation Method 1
a thermal oxidation process is used to form a thick amorphous silicon dioxide layer on the silicon parts
Data Source
Figure 1~3
AI summary
The invention relates to a micromechanical part, for example a clock watch movement part, comprising a silicon core (1). Part or all of the surface (3) of said silicon core is coated with a thick amorphous material (2). Said material is preferably silicon dioxide and is at least five times thicker than native silicon dioxide.