MEMS Protrusion Fabrication for Reduced Bending and Breakage
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Solution Overview
Problem
Existing MEMS devices with oblong protrusions are vulnerable to bending or breaking, affecting their performance and functionality.
Innovation Solution
A method involving anisotropic etching and corner lithography is used to create a MEMS device with a protrusion having a broad base and a shorter, less vulnerable lower section, utilizing a monocrystalline wafer substrate and filler material to form a robust and less prone to damage tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If an oblong protrusion is created in MEMS devices, then the device structure is formed, but the protrusion becomes vulnerable to bending or breaking
Solution Approach 1:
The protrusion is divided into two distinct sections: an upper recess section and a lower recess section. This segmentation allows each section to be optimized independently - the upper section provides structural support while the lower section maintains the required functional shape, thereby reducing overall vulnerability
Solution Approach 2:
Different regions of the protrusion are given different properties through selective etching. The upper recess section has different dimensional characteristics compared to the lower recess section, allowing the base to be broader and more stable while the lower section remains functional but shorter and less vulnerable
2Manufacturing precision
If corner lithography is performed to create a broad base, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The mask is placed at the nadir (bottom) of the upper recess section before the lower section is etched. This preliminary positioning of the mask enables precise control of the lower recess geometry in a subsequent etching step, achieving high manufacturing precision through planned sequential operations
Solution Approach 2:
Corner lithography utilizes the vertical dimension by placing the mask at the nadir of the upper recess rather than on the surface. This three-dimensional masking approach enables precise control of the lower recess section's geometry, achieving high precision without requiring complex lateral patterning
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 method produces a mechanically robust MEMS device with reduced vulnerability, allowing for precise manipulation and minimal damage during sample injection or extraction, while maintaining mechanical strength and stiffness.
Implementation Method 1
creating the upper recess section in the wafer substrate using anisotropic etching
Implementation Method 2
performing directional etching using the cover layer as a mask so as to form the lower recess section
Data Source
AI summary
A method of manufacturing a MEMS device comprising a main body and a protrusion. To provide a generic method of manufacturing a protrusion with reduced vulnerability, the method includes creating a recess in a wafer substrate, said recess having an upper recess section and a lower recess section. The upper recess section is created using anisotropic etching and the lower recess section is formed using corner lithography followed by directional etching. Finally, a filler material is introduced in the recess and at least part of the wafer substrate material is removed so as to expose the filler material introduced in the recess. Additionally, the method allows for the batch-wise production of protrusions having oblique ends.