Patterned Structure Fabrication via Spacer-Assisted Self-Aligned Patterning
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Solution Overview
Problem
The semiconductor industry faces challenges in fabricating miniaturized patterned structures due to the limitations of conventional exposure techniques, leading to increased complexity and cost in manufacturing processes, especially when forming different shapes, dimensions, and densities in the same layer or different regions.
Innovation Solution
A method utilizing spacers to achieve self-aligned patterning, integrating patterning processes across different regions, and reducing the number of required photomasks to improve the process window, involving multiple pattern transfer layers and spacer formations to create specific patterns and layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional exposure techniques are used for miniaturization, then existing manufacturing processes can be maintained, but the techniques approach their limits and cannot achieve further miniaturization
Solution Approach 1:
The patent divides the patterning process into multiple sequential steps using multiple pattern transfer layers (first pattern transfer layer, second pattern transfer layer, third pattern transfer layer) instead of attempting to form all patterns in a single exposure step. This segmentation allows each layer to be processed independently, achieving miniaturization beyond the limits of conventional single-step exposure techniques.
Solution Approach 2:
The patent introduces vertical stacking of multiple pattern transfer layers to solve the miniaturization problem. By forming patterns in different layers at different heights and then selectively removing portions, the process achieves complex 3D pattern formation that overcomes the 2D limitations of conventional exposure techniques.
2Adaptability or versatility
If different photolithography processes are used to form patterned structures with different shapes, dimensions, and densities in the same layer or different regions, then the required patterns can be achieved, but the manufacturing process becomes more complicated and costs increase
Solution Approach 1:
The patent employs multiple pattern transfer layers that can be used for different purposes: some layers form patterns in first regions, others form patterns in second regions, and they can be selectively removed or retained. This universal approach allows a single multi-layer system to handle various pattern formation requirements (different shapes, dimensions, densities) without requiring separate dedicated processes for each case.
Solution Approach 2:
The patent performs preliminary patterning actions by forming multiple pattern transfer layers with different patterns before final pattern formation. The first pattern transfer layer, second pattern transfer layer, and third pattern transfer layer are all formed in advance with their respective patterns, allowing subsequent selective removal and pattern transfer processes to achieve complex final patterns without requiring complex real-time processing.
3Reliability
If multiple pattern transfer layers are formed and selectively removed to achieve self-aligned patterning, then manufacturing yield is enhanced and process window is improved, but the number of fabrication steps increases
Solution Approach 1:
The patent uses the pattern transfer layers themselves as masks for subsequent patterning steps. Each pattern transfer layer serves dual purposes: it defines the pattern to be formed and simultaneously acts as the masking layer that protects areas during etching. This self-service approach eliminates the need for separate mask layers, reducing overall process complexity despite the multiple layers involved.
Solution Approach 2:
The patent combines multiple functions into the pattern transfer layers: pattern definition, masking, and alignment reference. By merging these functions into the same structural elements (the pattern transfer layers), the process achieves self-aligned patterning where alignment is automatically ensured by the physical presence of the layers themselves, improving yield without requiring additional alignment steps.
Data Source
AI summary
A method of fabricating a patterned structure includes the following steps. A first pattern transfer layer and a second pattern transfer layer are formed on a material layer. A part of the second pattern transfer layer is patterned to be a first pattern. A first spacer is formed on sidewalls of the first pattern. The first pattern transfer layer is patterned to be a second pattern and a third pattern. A cover layer is formed covering the first pattern, the first spacer, the second pattern, and the third pattern. A part of the cover layer is removed for exposing the first pattern and the first spacer. The first spacer is removed, and a patterning process is performed to the first pattern transfer layer with the first pattern and the cover layer as a mask. The second pattern is patterned to be a fourth pattern by the patterning process.