Multi-zone Gas Distribution Plate for MEMS Etching Uniformity
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Solution Overview
Problem
Achieving uniform plasma-based etching in the manufacture of microelectromechanical systems (MEMS) motion sensors is challenging due to non-uniformities in plasma distribution caused by the layout of the process chamber, leading to inconsistencies in critical dimensions and drive frequencies, which affect the sensitivity and accuracy of gyroscopes and accelerometers.
Innovation Solution
A multi-zone gas distribution plate (GDP) with zones having different cross-sectional profiles for holes is designed to compensate for non-uniform plasma distribution, allowing for improved etching uniformity by adjusting process gas flow based on plasma intensity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional gas distribution plate with uniform holes is used, then the device complexity is low, but the etching uniformity deteriorates due to non-uniform plasma distribution
Solution Approach 1:
The gas distribution plate is divided into multiple zones, each with holes of different cross-sectional profiles. This segmentation allows different regions to deliver different gas flow characteristics, compensating for non-uniform plasma distribution and improving etching uniformity across the substrate surface.
Solution Approach 2:
Different zones of the gas distribution plate are assigned different hole cross-sectional profiles tailored to local plasma intensity requirements. Regions with lower plasma intensity receive zones with larger or more numerous holes to increase gas flow, while regions with higher plasma intensity receive zones with smaller holes to reduce gas flow, achieving localized optimization of etching uniformity.
2Manufacturing precision
If the hole cross-sectional profiles are made different across zones, then the plasma distribution uniformity improves, but the ease of manufacture deteriorates
Solution Approach 1:
The invention varies the cross-sectional profile parameters of holes (such as diameter, shape, or orientation) across different zones of the gas distribution plate. This parameter changes approach allows systematic control of gas flow distribution to match plasma intensity variations, improving plasma distribution uniformity while maintaining manufacturability through controlled geometric variations.
3Manufacturing precision
If the gas flow is increased in low plasma intensity regions, then the plasma uniformity improves, but the energy consumption increases
Solution Approach 1:
The gas distribution plate implements local quality by providing different hole cross-sectional profiles in different zones. Low plasma intensity regions receive zones with larger or more numerous holes to increase local gas flow and plasma generation, while high plasma intensity regions receive zones with smaller holes to maintain lower gas flow and reduce energy consumption, achieving plasma uniformity with optimized energy usage.
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 multi-zone GDP enhances etching uniformity, increasing the sensitivity and accuracy of MEMS motion sensors by addressing non-uniformities in plasma distribution, thereby improving the performance of MEMS devices during bulk manufacture.
Implementation Method 1
A multi-zone gas distribution plate (GDP) with zones having different cross-sectional profiles for holes is designed to compensate for non-uniform plasma distribution, allowing for improved etching uniformity by adjusting process gas flow based on plasma intensity variations
Data Source
AI summary
A multi-zone gas distribution plate (GDP) for high uniformity in plasma-based etching is provided. A housing defines a process chamber and comprises a gas inlet configured to receive a process gas. A GDP is arranged in the process chamber and is configured to distribute the process gas within the process chamber. The GDP comprises a plurality of holes extending through the GDP, and further comprises a plurality of zones into which the holes are grouped. The zones comprise a first zone and a second zone. Holes of the first zone share a first cross-sectional profile and holes of the second zone share a second cross-sectional profile different than the first cross-sectional profile. A method for designing the multi-zone GDP is also provided.