Buried Connecting Structure for Micromechanical Component Sealing
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Solution Overview
Problem
The existing methods for manufacturing micromechanical components, such as inertial sensors, face challenges due to the topography of connecting structures on the substrate, which interfere with photolithographic patterning, leading to uneven photoresist deposition and unwanted scattering effects, resulting in fluctuations in structural dimensions and negative effects on electrical properties.
Innovation Solution
A method where a buried connecting structure is formed on the first substrate, allowing for a flat upper surface and subsequent precise microstructure production, with the connecting structure being recessed and filled with bonding material, providing high mechanical rigidity through a meshed configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connecting structure is formed on the upper surface of the functional substrate prior to forming the microstructure, then hermetic sealing is achieved, but photolithographic patterning precision deteriorates due to topography-induced photoresist unevenness
Solution Approach 1:
The connecting structure is formed in advance (preliminarily) on the functional substrate, but is recessed into the substrate rather than projecting from it. This preliminary formation allows the microstructure to be subsequently formed with high precision on a flat upper surface, while the connecting structure remains in place to provide hermetic sealing when bonded with the cap substrate.
Solution Approach 2:
The connecting structure is transitioned from a surface-projecting form to a subsurface-recessed form by changing its vertical position dimension. The connecting structure is formed at least partially within the functional substrate, extending from the upper surface downward, thereby eliminating topography interference while maintaining sealing functionality.
2Reliability
If the connecting structure is positioned close to the microstructure to ensure sealing, then hermetic sealing is improved, but structural dimension control deteriorates due to scattering effects
Solution Approach 1:
The connecting structure is preliminarily formed as a recessed structure within the functional substrate before microstructure fabrication. This preliminary recessed configuration allows close positioning to the microstructure for effective sealing while preventing scattering effects from affecting photolithographic patterning, since the connecting structure does not project from the upper surface during microstructure formation.
3Area of stationary object
If the connecting structure projects from the substrate surface, then bonding area is increased, but mechanical rigidity deteriorates due to lack of substrate integration
Solution Approach 1:
The connecting structure is nested within the functional substrate, with at least a portion of the connecting structure formed inside the substrate volume. The connecting structure extends from the upper surface downward into the substrate, creating an integrated, meshed configuration that enhances mechanical rigidity while maintaining adequate bonding area for hermetic sealing.
Solution Approach 2:
The connecting structure utilizes a composite configuration where bonding material is integrated with the functional substrate material. The connecting structure comprises a first material different from the functional substrate material, creating a composite structure that provides both adequate bonding area and enhanced mechanical rigidity through substrate integration.
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 reliable and precise production of micromechanical components with improved mechanical rigidity, reducing the adverse effects of topography on microstructure dimensions and electrical properties, and enhancing the hermetic sealing of the microstructure.
Implementation Method 1
joining the first and second substrates by carrying out a bonding process; the first and second connecting structures being joined to form a common connecting structure
Data Source
AI summary
A method is described for manufacturing a micromechanical component. The method includes providing a first substrate, forming a first connecting structure on the first substrate, and forming a microstructure on the first substrate after forming the first connecting structure. The microstructure has at least one movable functional element. The method further includes providing a second substrate having a second connecting structure, and joining the first and second substrates by carrying out a bonding process, the first and second connecting structures being joined to form a common connecting structure, and a sealed cavity being formed in the region of the microstructure. The method provides that the first connecting structure takes the form of a buried connecting structure extending up to an upper surface of the first substrate. Also described is a related micromechanical component.