Contact Hole Shrinking via MLD for Smoother EUV Resist Patterns
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Solution Overview
Problem
EUV lithography faces challenges with stochastic noise leading to non-uniform feature sizes and reduced throughput due to high sidewall roughness and CD non-uniformity, limiting the scaling of semiconductor devices to smaller dimensions.
Innovation Solution
A chemical vapor deposition (CVD) process, specifically molecular layer deposition (MLD), is used to treat the resist layer with precursor gases, infusing into the resist layer to reduce feature dimensions and smooth sidewalls, allowing for smaller critical dimensions without increasing EUV dosage or mask opening size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If EUV lithography is used to achieve smaller critical dimensions, then feature size is reduced, but sidewall roughness increases and stochastic noise issues occur
Solution Approach 1:
The patent applies preliminary action by performing MLD treatment on the resist layer before pattern transfer to underlying layers. The MLD process modifies the resist layer properties in advance, creating a more robust pattern that maintains dimensional control during subsequent etching processes, thereby reducing sidewall roughness before the critical dimension is fully realized in the final structure
Solution Approach 2:
The patent changes physical and chemical parameters of the resist layer through MLD processing. By depositing molecular layers that modify the resist's chemical composition and physical properties, the process alters the resist's response to EUV lithography, enabling smaller critical dimensions to be achieved with reduced sidewall roughness and improved stochastic noise performance
2Reliability
If larger mask openings are provided to increase image contrast, then stochastic noise is reduced, but formation of small holes is limited
Solution Approach 1:
The MLD process changes the chemical and physical parameters of the resist layer, enhancing its sensitivity and contrast response. This allows smaller mask openings to achieve the same effective image contrast as larger openings would provide in conventional resists, enabling formation of smaller holes while maintaining low stochastic noise
Solution Approach 2:
The patent creates a composite structure by integrating MLD-deposited molecular layers with the base resist material. This composite resist system combines the advantages of both materials, achieving enhanced image contrast and reduced stochastic noise while maintaining the ability to form small contact holes through optimized chemical composition and structural properties
3Reliability
If higher EUV dosages are applied to reduce stochastic noise, then image contrast increases, but throughput decreases
Solution Approach 1:
The MLD process modifies the resist layer's physical and chemical parameters to enhance its efficiency in utilizing EUV photons. The treated resist requires lower EUV dosage to achieve the same image contrast and stochastic noise performance, directly improving throughput while maintaining reliability
Solution Approach 2:
The MLD-pre-treated resist layer exhibits self-enhancing properties where the modified chemical structure automatically provides improved contrast and reduced stochastic noise at lower dosages. The resist essentially serves itself by having pre-installed molecular structures that optimize its response to EUV radiation, eliminating the need for high dosages and thereby improving throughput
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
The MLD process enables enhanced scaling to smaller critical dimensions by reducing feature sizes and sidewall roughness, improving throughput and local critical dimension uniformity without sacrificing EUV lithography performance.
Implementation Method 1
a chemical vapor deposition (CVD) process. In an embodiment, the CVD process reduces a dimension of the patterned feature, and the CVD process includes flowing a precursor gas into a chamber that infuses into the resist layer
Implementation Method 2
treating a resist layer with a patterned feature with a molecular layer deposition (MLD) process in a chamber. In an embodiment, the MLD process includes (a) supplying a pulse of a precursor gas into the chamber
Data Source
AI summary
Embodiments disclosed herein include a method for treating a resist layer comprising a patterned feature with a chemical vapor deposition (CVD) process. In an embodiment, the CVD process reduces a dimension of the patterned feature, and the CVD process includes flowing a precursor gas into a chamber that infuses into the resist layer. In an embodiment, the method further comprises transferring the patterned feature into a layer below the resist layer.