Double Exposure Lithography Pattern Formation
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Solution Overview
Problem
In semiconductor manufacturing, maintaining desired critical dimensions during lithography patterning is challenging due to pattern collapse and CD degradation, especially with high aspect ratio features and double patterning techniques, which also increase manufacturing costs and introduce issues like profile scum and round corners.
Innovation Solution
A method involving the formation of multiple layers with specific properties, including an underlying material layer, a middle layer, and a top layer, where patterned resist layers are used for double exposure and single etch processes to minimize CD variation and manufacturing costs, utilizing etching processes that differentiate between the layers to achieve precise feature formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double patterning techniques are utilized to achieve smaller feature sizes, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent divides the patterning process into multiple exposure steps (first exposure and second exposure) with different resist layers (first resist layer and second resist layer). Each exposure step forms a portion of the final pattern, allowing complex patterns to be built incrementally while maintaining control over critical dimensions at each stage.
Solution Approach 2:
The patent introduces a vertical dimension by stacking multiple resist layers and material layers (first material layer, second material layer, third material layer) to achieve double patterning. This multi-layer approach allows pattern formation in three-dimensional space, enabling precise CD control through selective etching of each layer.
2Manufacturing precision
If high aspect ratio resist layers are used to achieve smaller feature sizes, then manufacturing precision is improved, but reliability decreases due to pattern collapse and CD degradation
Solution Approach 1:
The patent segments the high aspect ratio patterning task across multiple lower aspect ratio steps. By forming patterns in separate exposure steps with intermediate material layers, each resist layer has reduced aspect ratio requirements, improving pattern stability and reducing collapse while still achieving the final small feature dimensions.
Solution Approach 2:
The patent introduces intermediate material layers (first material layer, second material layer, third material layer) between resist layers that act as spacers and structural supports. These intermediary layers provide mechanical support during processing, preventing pattern collapse while enabling the formation of high-resolution features.
3Manufacturing precision
If double patterning techniques are utilized to achieve smaller feature sizes, then manufacturing precision is improved, but loss of substance increases due to profile scum formation
Solution Approach 1:
The patent uses selective removal of material layers through targeted etching processes. Each material layer is removed only where needed based on the pattern formed in the corresponding resist layer, minimizing unnecessary material loss and preventing profile scum formation by precisely controlling where etching occurs.
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 reduces manufacturing costs and minimizes critical dimension variations, enabling the formation of precise features with reduced pattern collapse and improved etching resistance, suitable for advanced semiconductor technologies.
Implementation Method 1
etching the first and second material layers uncovered by the first and second patterned resist layers
Data Source
AI summary
A method of lithography patterning includes forming a first material layer on a substrate; forming a first patterned resist layer including at least one opening therein on the first material layer; forming a second material layer on the first patterned resist layer and the first material layer; forming a second patterned resist layer including at least one opening therein on the second material layer; and etching the first and second material layers uncovered by the first and second patterned resist layers.