Multi-Color Resist Stack for Dense LLE Patterning
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Solution Overview
Problem
Current double patterning techniques, such as LELE, face challenges in scaling metal interconnect structures due to increased complexity and the need for precise mask alignment, which complicates the formation of dense patterns and requires additional etch steps, limiting the resolution and efficiency in integrated circuit manufacturing.
Innovation Solution
A multi-color resist structure is formed using a combination of non-chemically amplified resist (n-CAR) and CAR organic resist layers, with a multi-layer patterning stack, facilitating a litho-litho-etch (LLE) process that reduces the number of etch steps and inter-tool wafer exchange sequences, enabling improved feature placement and resolution without the need for multiple deposition and etch steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If LELE double patterning is used to increase pattern density, then manufacturing precision is improved, but device complexity increases due to twice the number of steps and complicated etch steps
Solution Approach 1:
The patent combines two separate lithography and etch processes into a single integrated LLE process. The multi-color resist structure allows both patterns to be formed and transferred in one etch step, merging what would traditionally require four separate steps (litho-etch-litho-etch) into three steps (litho-litho-etch), thereby reducing process complexity while maintaining high pattern density.
Solution Approach 2:
The patent segments the patterning process into distinct color layers (first color resist and second color resist) that can be independently exposed and developed. This segmentation allows complex patterns to be built up from simpler components, achieving high pattern density through systematic division of the patterning task while streamlining the overall process flow.
2Manufacturing precision
If LELE double patterning is used to achieve finer patterns, then manufacturing precision is improved, but loss of time increases due to inter-tool wafer exchange sequences
Solution Approach 1:
The patent merges the pattern transfer operations into a single etch step that processes both first color and second color patterns simultaneously. This eliminates the need for separate etch steps and intermediate wafer exchanges, reducing cycle time while achieving the same level of feature refinement that would otherwise require multiple sequential operations.
3Device complexity
If traditional single exposure patterning is used, then device complexity is reduced, but manufacturing precision deteriorates due to inability to print dense patterns
Solution Approach 1:
The patent applies different resist types (n-CAR and CAR organic resist) to different color layers, allowing each layer to be optimized for its specific patterning requirements. This local differentiation enables the system to achieve high pattern density in both colors while maintaining process simplicity, as each resist can be tailored to its specific function rather than requiring a complex single-exposure system.
4Manufacturing precision
If multiple deposition and etch steps are used in LELE, then manufacturing precision is improved, but ease of manufacture deteriorates due to additional process complexity
Solution Approach 1:
The patent merges the pattern transfer operations into a single etch step that processes both first color and second color patterns simultaneously. This eliminates the need for separate etch steps and intermediate wafer exchanges, reducing cycle time while achieving the same level of feature refinement that would otherwise require multiple sequential operations.
Data Source
AI summary
A method of forming a multi color resist structure includes providing a substrate including an underlayer material; forming a first organic planarizing layer on the substrate; forming a first anti reflecting layer on the first organic planarizing layer, forming and developing a first patterned resist on the first anti reflecting layer; forming a second organic planarizing layer on the first anti reflecting layer and on the first patterned resist; forming a second anti reflecting layer on the second organic planarizing layer and forming and developing the second patterned resist, wherein the first patterned resist is a non-chemically amplified resist (n-CAR) or metal resist and the second patterned resist is CAR organic resist.