MEMS Micro-Mirror Fabrication with Selective ARC Removal
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Solution Overview
Problem
Current MEMS nanostructure fabrication techniques face challenges in achieving precise formation and integration of micro-mirrors with enhanced reflectivity and bio-compatibility for applications such as inertial sensors and biological sensing structures, particularly in forming micro-mirrors with precise dimensions and bio-compatible materials.
Innovation Solution
A method involving recessing a substrate to form mesas, depositing a light reflecting layer, forming a protection layer, and an anti-reflective coating (ARC) layer, followed by selective removal to expose the mesa surfaces, allowing for the integration of a micro-mirror structure with enhanced reflectivity and bio-compatibility, using materials like aluminum-copper for the light reflecting layer and titanium nitride for the ARC layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional MEMS fabrication techniques are used, then manufacturing process is simple, but manufacturing precision of micro-mirrors is insufficient
Solution Approach 1:
The fabrication process is divided into multiple sequential steps including recess formation, light reflecting layer deposition, protection layer formation, ARC layer formation, and selective removal. Each step addresses a specific aspect of micro-mirror formation, enabling precise control over the final structure while maintaining systematic process management
Solution Approach 2:
The light reflecting layer is deposited over the recessed substrate before the protection layer is formed. This preliminary action ensures that the reflective surface is established early in the process, allowing subsequent layers to be configured around it without compromising the mirror's optical properties
2Illumination intensity
If light reflecting layer is deposited to enhance reflectivity, then optical performance is improved, but device complexity increases
Solution Approach 1:
The micro-mirror structure employs a composite layered architecture consisting of a light reflecting layer deposited over the recessed substrate, followed by a protection layer and an anti-reflective coating layer. This composite structure optimizes optical performance by combining materials with different functional properties while maintaining structural integrity
Solution Approach 2:
The light reflecting layer is selectively deposited only over the recessed portions of the substrate where micro-mirrors are to be formed, rather than covering the entire substrate. This localized approach enhances reflectivity where needed while reducing unnecessary material usage and process complexity
3Reliability
If protection layer and ARC layer are added for bio-compatibility, then bio-compatibility is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The protection layer is formed over the light reflecting layer before the anti-reflective coating layer is deposited. This preliminary protection ensures that the delicate reflective surface is safeguarded during subsequent processing steps, reducing the risk of damage and maintaining manufacturing precision
Solution Approach 2:
The combination of protection layer and anti-reflective coating layer creates a composite structure that provides both mechanical protection and optical functionality. This multi-layer composite approach enhances bio-compatibility and structural integrity while managing the complexity of precise thickness control through specialized deposition processes
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 MEMS nanostructures with improved reflectivity and bio-compatibility, enhancing their performance in applications like biological sensing and optical systems by ensuring precise control over the micro-mirror surfaces and preventing metal complex formation that could interfere with analyte detection.
Implementation Method 1
removing the ARC layer in a wet solution comprising H2O2, the ARC layer being exposed to the H2O2 at a flow rate greater than about 10 standard cubic centimeters per minute (sccm)
Implementation Method 2
depositing a light reflecting layer, followed by selective removal to expose the mesa surfaces, which includes using a photo resist layer and etching processes to create openings capable of housing analytes, enhancing reflectivity and bio-compatibility
Data Source
AI summary
A method of forming a semiconductor device includes depositing a light reflecting layer over a substrate. The method also includes forming a protection layer over the light reflecting layer. The method further includes forming an anti-reflective coating (ARC) layer over the protection layer. The method additionally includes forming an opening in the ARC layer, the protection layer and the light reflecting layer exposing the substrate. The method also includes removing the ARC layer in a wet solution comprising H2O2, the ARC layer being exposed to the H2O2 at a flow rate greater than about 10 standard cubic centimeters per minute (sccm).