Selective Mandrel Formation for Uniform EUV Spacer Patterning
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Solution Overview
Problem
EUV lithography faces challenges in forming uniform sidewall spacers due to limited mandrel height and stochastic exposure effects, leading to random failures and increased complexity in semiconductor manufacturing.
Innovation Solution
A selective deposition and trim process is used to form a mandrel directly from a patterned resist layer, allowing for increased mandrel height and uniform spacer formation, which is then used as an etch mask to pattern underlying layers, all within a single plasma processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV lithography is used to pattern resist at sub-10 nm nodes, then resolution is improved, but stochastic exposure effects cause random printing failures
Solution Approach 1:
The patent segments the patterning process into multiple steps (mandrel formation, spacer deposition, mandrel removal) to overcome the limitations of single-step EUV lithography. This multi-step approach allows each step to be optimized independently, improving both resolution and reliability.
Solution Approach 2:
The patent introduces a mandrel structure as an intermediary element that facilitates the formation of final patterns. The mandrel serves as a template for spacer deposition, enabling more reliable pattern formation than direct EUV exposure alone.
2Device complexity
If conventional lithography is used to print patterns, then manufacturing complexity is reduced, but feature size resolution deteriorates at sub-10 nm nodes
Solution Approach 1:
The patent merges lithography with plasma processing steps (deposition, etching) in an integrated flow. This combination allows the process to achieve sub-10 nm resolution while managing complexity through synergistic process integration rather than relying solely on more complex lithography tools.
3Manufacturing precision
If mandrel height is increased to improve spacer uniformity, then manufacturing precision is improved, but the number of deposition steps increases
Solution Approach 1:
The patent implements continuous deposition processes where mandrel material is deposited in a single continuous step rather than multiple discrete steps. This maintains the necessary mandrel height for uniform spacer formation while minimizing the number of process interruptions and steps.
4Manufacturing precision
If multiple patterning masks are used to achieve higher resolution, then manufacturing precision is improved, but processing complexity and cost increase
Solution Approach 1:
The patent employs self-aligned spacer formation where the spacer structure automatically forms with the correct dimensions and alignment based on the mandrel geometry. This self-service mechanism eliminates the need for additional alignment steps and masks that would otherwise be required to achieve the same resolution.
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 process enables the formation of thinner features with improved resolution and reduced manufacturing complexity by enhancing mandrel aspect ratio and allowing integrated processing steps, thereby improving throughput and reducing costs.
Implementation Method 1
forming a mandrel in a plasma processing chamber by selectively depositing a mandrel material over the patterned resist layer
Implementation Method 2
removing the mandrel after forming the spacers, where depositing the mandrel material, forming the spacers, removing the mandrel are performed in a single process step
Data Source
AI summary
A method of forming a device includes forming a patterned resist layer over a substrate using an extreme ultraviolet (EUV) lithography process. The method includes forming a mandrel in a plasma processing chamber by selectively depositing a mandrel material over the patterned resist layer, the mandrel including the patterned resist layer and the mandrel material.