U-Shape Mask Layer Patterning for SADP Symmetry
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Solution Overview
Problem
Traditional Self-Aligned Double Patterning (SADP) methods suffer from asymmetry issues in spacer formation, leading to inaccurate pattern transfer due to the asymmetrical influence of the first spacer on the second spacer, which affects the shape and subsequently the patterning process.
Innovation Solution
A patterning method involving the formation of multiple mask layers with sacrificial layers, where U-shape mask layers are created to maintain symmetry and accuracy, using protrusions of the U-shape mask layers as a mask for precise pattern transfer to the material layer, employing techniques like chemical vapor deposition, atomic layer deposition, and dry etching for layer formation and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional SADP method is used to reduce line width and line space, then smaller feature sizes are achieved, but asymmetry in spacer formation causes inaccurate pattern transfer
Solution Approach 1:
The patent segments the mask structure into multiple distinct layers (first mask layer, first photoresist layer, second mask layer, third mask layer) with different functions. Each layer is formed and processed separately to maintain symmetry, preventing the asymmetry problem that occurs in traditional SADP where a single spacer structure must serve multiple purposes.
Solution Approach 2:
The patent introduces sacrificial layers as intermediary structures between the mask layers and the material layer. These sacrificial layers are conformally deposited and then selectively removed to create symmetric U-shaped mask structures, acting as mediators that ensure symmetric pattern transfer without directly becoming part of the final pattern.
2Manufacturing precision
If multiple mask layers with sacrificial layers are formed to maintain symmetry, then pattern transfer accuracy is improved, but process complexity increases
Solution Approach 1:
The patent performs preliminary conformal deposition of multiple mask layers and sacrificial layers before the final patterning step. By pre-forming these symmetric structures with precise thickness control through conformal deposition, the actual patterning process becomes simpler and more accurate, as the symmetry is already established in the mask structure itself.
Solution Approach 2:
The patent changes the physical and chemical parameters of each layer (different materials, different deposition conditions, different etch selectivities) to create distinct functional zones. This allows each layer to be processed independently with optimized parameters, maintaining symmetry while managing complexity through parameter differentiation rather than structural complexity.
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 method ensures accurate pattern transfer by maintaining the desired shape of the mask layers, allowing for precise control and symmetry in the patterning process, thereby overcoming the asymmetry issues in traditional SADP methods.
Implementation Method 1
A second mask layer covering the mask structure is conformally formed on the material layer. A third mask layer is conformally formed on the first mask layer and the first U-shape mask layer
Implementation Method 2
employing techniques like chemical vapor deposition, atomic layer deposition, and dry etching for layer formation and removal
Implementation Method 3
employing techniques like chemical vapor deposition, atomic layer deposition, and dry etching for layer formation and removal
Data Source
AI summary
A patterning method is provided. Mask structures including first mask layers and first photoresist layers are formed sequentially on a material layer. A second mask layer covering the mask structures is conformally formed on the material layer. First sacrificed layers are formed between the mask structures. Parts of the second mask layer are removed to expose the first photoresist layers and form first U-shape mask layers. The first photoresist layers and the first sacrificed layers are removed. A third mask layer having first surfaces and second surfaces lower than the first surfaces is conformally formed on the material layer. Second sacrificed layers are formed on the second surfaces. Parts of the third mask layer are removed to expose protrusions of the first U-shape mask layers and form second U-shape mask layers. The material layer is patterned by using protrusions of the second U-shape mask layers as masks.