Micromechanical Component With Through Electrode
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Solution Overview
Problem
Current methods for producing micromechanical components, such as inertial sensors, are complex, costly, and prone to errors due to the need for buried conductor tracks and sealing glass, which increase component size and risk of outgassing.
Innovation Solution
A method involving a first substrate with a microstructure and a second substrate with an electrode, where the substrates are connected via metallic layers for a hermetically sealed cavity, eliminating the need for buried conductor tracks and using eutectic or thermocompression bonding to ensure a small, cost-effective, and gas-tight assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buried conductor tracks are used to provide electrical paths to contact elements, then electrical connectivity is achieved, but the component area increases and manufacturing complexity increases
Solution Approach 1:
The patent moves the electrode from the traditional planar buried conductor track configuration to a three-dimensional structure where the electrode is formed on the cap substrate and extends into the cavity space. This dimensional change allows electrical connectivity without increasing the planar component footprint, as the electrode utilizes the vertical cavity space rather than requiring lateral expansion.
Solution Approach 2:
Instead of forming conductor tracks in the functional substrate and bringing contact elements to the exterior, the patent inverts the approach by forming the electrode on the cap substrate and allowing it to abut the cavity. This inversion eliminates the need for complex buried conductor tracks and external contact elements, reducing both area and manufacturing complexity.
2Manufacturing precision
If more than ten lithographic structuring levels are used to form the microstructure, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent segments the manufacturing process into distinct modules: functional substrate fabrication, cap substrate fabrication with electrode formation, and bonding. This segmentation allows each module to be optimized independently, reducing the need for numerous lithographic structuring levels while maintaining precision through focused process control in each segment.
Solution Approach 2:
The electrode is formed on the cap substrate in advance during cap substrate fabrication, before bonding to the functional substrate. This preliminary action eliminates the need for subsequent complex lithographic steps to create conductor tracks and contact elements, reducing overall process complexity while maintaining manufacturing precision.
3Reliability
If sealing glass is used to connect substrates, then hermetic sealing is achieved, but the bonding frame width increases and solvent outgassing may occur
Solution Approach 1:
The patent changes the material parameter from sealing glass to metallic layers for substrate connection. This parameter change achieves hermetic sealing through the metallic bond while eliminating the need for a wide bonding frame, as metallic bonding can be performed with thinner connection layers. It also eliminates solvent outgassing issues inherent to sealing glass application methods.
Solution Approach 2:
The patent replaces the mechanical screen printing process used for applying sealing glass with a metallic layer deposition and bonding process. This substitution eliminates the solvent-based application method that causes outgassing and allows for a thinner bonding frame while maintaining hermetic sealing reliability.
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 results in a compact, inexpensive micromechanical component with reduced process steps and no risk of outgassing, allowing for precise pressure control within the cavity.
Implementation Method 1
using eutectic or thermocompression bonding to ensure a small, cost-effective, and gas-tight assembly
Implementation Method 2
using eutectic or thermocompression bonding to ensure a small, cost-effective, and gas-tight assembly
Implementation Method 3
the first and second substrates being connected to one another in such a way that the functional element is separated from a cavity enclosed by the first and second substrates... an electrode for capacitively detecting a deflection of the functional element
Data Source
Figure 1~2
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Figure 6
AI summary
The invention relates to a method for producing a micromechanical component (300) that comprises providing a first substrate (100), forming a microstructure (150) on the first substrate (100), wherein the microstructure (150) comprises a moving function element (151), providing a second substrate (200), and forming in the second substrate (200) an electrode (251) for capacitively measuring a deflection of the function element (151). The method further comprises connecting the first and the second substrates (100; 200), wherein a closed cavity which encloses the function element (151) is formed, and wherein the electrode (251) adjoins the cavity in an area of the function element (151).