Resonant Transducer Vibration Beam Strain Control Without Buckling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resonant transducer manufacturing methods face challenges in accurately controlling high tensile strain in thick vibration beams, leading to buckling issues and reduced sensitivity, due to defects and dislocations caused by epitaxial growth and long diffusion times.
Innovation Solution
Diffusing impurities like boron or phosphorus into the vibration beam from three directions after its formation, allowing for controlled heat treatment to achieve high tensile strain without warping, and forming a thick vibration beam with precise impurity concentration management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If epitaxial growth is used to form the vibration beam, then the beam can be formed with controlled strain, but defects and dislocations occur reducing manufacturing precision
Solution Approach 1:
The patent changes the fundamental parameter of beam formation from epitaxial growth to selective removal of sacrificial layers. This parameter change eliminates the defects and dislocations inherent in epitaxial growth while maintaining the ability to control strain through impurity diffusion, thereby resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
The patent introduces sacrificial layers (silicon oxide and silicon nitride) as intermediary elements that are selectively removed to form the vibration beam. These intermediary layers enable precise control of beam geometry and strain without the defects associated with direct epitaxial growth, resolving the contradiction between manufacturing precision and reliability
2Manufacturing precision
If long diffusion time is used to achieve high tensile strain, then strain control improves, but manufacturing time increases reducing productivity
Solution Approach 1:
The patent performs preliminary impurity diffusion into the sacrificial layers before beam formation, creating a reservoir of diffusable impurities. This preliminary action allows for shorter final diffusion times to achieve the desired strain, resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The patent applies impurity diffusion locally to specific regions where strain control is needed, rather than requiring long-duration uniform diffusion throughout the entire structure. This localized approach achieves precise strain control while significantly reducing overall manufacturing time, resolving the contradiction between manufacturing precision and productivity
3Strength
If thick vibration beam is formed, then structural stability improves, but strain control becomes difficult reducing manufacturing precision
Solution Approach 1:
The patent segments the strain control process into multiple stages: preliminary diffusion into sacrificial layers, beam formation, and final diffusion adjustment. This segmentation enables precise strain control in thick beams by allowing incremental strain accumulation without compromising structural stability, resolving the contradiction between strength and manufacturing precision
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 the formation of high-tensile-strain vibration beams that are less prone to buckling, reduces wafer warping, and allows for accurate strain control, improving measurement capabilities and sensitivity.
Implementation Method 1
Diffusing impurities like boron or phosphorus into the vibration beam from three directions after its formation, allowing for controlled heat treatment to achieve high tensile strain without warping
Data Source
Figure 1A~1B
Figure 2A~2E
Figure 3A~3E
AI summary
A method of manufacturing a resonant transducer having a vibration beam includes: (a) providing an SOI substrate including: a first silicon layer; a silicon oxide layer on the first silicon layer; and a second silicon layer on the silicon oxide layer; (b) forming a first gap and second gap through the second silicon layer by etching the second silicon layer using the silicon oxide layer as an etching stop layer; (c) forming an impurity diffusion source layer on the second silicon layer; (d) forming an impurity diffused layer in a surface portion of the second silicon layer; (e) removing the impurity diffusion source layer through etching; and (f) removing at least a portion of the silicon oxide layer through etching such that an air gap is formed between the first silicon layer and a region of the second silicon layer surrounded by the first and second gaps.