MEMS and NEMS Structures With Sub-Lithographic Feature Patterning
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Solution Overview
Problem
Low-cost LCD manufacturing methods are inferior to CMOS alternatives in producing MEMS and NEMS devices with narrow linewidths or sub-micron features due to limitations in lithographic capabilities.
Innovation Solution
A method involving an etch stop layer is used to separate dependencies among different layers, allowing for improved pattern transfer accuracy and material selection, and material diffusion is utilized to pattern structures below the lithographic limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography processes are used, then manufacturing process is simple, but structural features cannot be manufactured below lithographic limit dimensions
Solution Approach 1:
The manufacturing process is divided into multiple sequential stages: forming mandrels at first pitch, depositing spacers, selectively removing portions, and repeating the process. This segmentation allows achievement of sub-lithographic dimensions through multiple simpler steps rather than requiring a single complex lithography process
Solution Approach 2:
The patent transitions from two-dimensional lithographic patterning to three-dimensional spacer formation. By depositing conformal layers that wrap around mandrels and then anisotropically etching, the process creates features in the vertical dimension that translate to precise horizontal dimensions, bypassing lithographic resolution limits
2Manufacturing precision
If lithographic limit is approached, then manufacturing precision improves, but manufacturing cost increases
Solution Approach 1:
Spacer materials serve as intermediaries that define the final feature dimensions. The spacer thickness, controlled by conformal deposition processes with better precision than lithography, determines the structural feature size. This intermediary approach allows precise dimension control using more cost-effective deposition equipment rather than expensive advanced lithography tools
3Manufacturing precision
If feature size is reduced below lithographic limit, then device performance improves, but manufacturing reliability decreases
Solution Approach 1:
The spacer structure is self-aligned to the mandrel, automatically defining precise feature locations and dimensions without requiring additional alignment steps. The conformal deposition process naturally creates uniform thickness around mandrels of varying shapes, and anisotropic etching self-stop at the mandrel surface ensures consistent feature depths, all without complex process control
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
Enables the production of MEMS and NEMS devices with sub-micron features at low cost, enhancing flexibility and precision in manufacturing processes.
Implementation Method 1
A method of manufacturing an electromechanical systems structure includes manufacturing sub-micron structural features. In some embodiments, the structural features are less than the lithographic limit of a lithography process.
Implementation Method 2
The etch may be a self-aligned etch process in which case no additional lithography or alignment is needed to perform the etch.
Data Source
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AI summary
A method of manufacturing an electromechanical systems structure includes manufacturing sub-micron structural features. In some embodiments, the structural features are less than the lithographic limit of a lithography process.