Photoresist Basic Gas Treatment for Uniform Lithography Profiles
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Solution Overview
Problem
The existing photolithography processes in semiconductor manufacturing result in undesirable T-topping pattern profiles and non-uniform critical dimensions due to photoacid diffusion in the photoresist layer, leading to image blurring and poor resolution.
Innovation Solution
Treating the photoresist layer with a basic gas after exposure to react with diffusing photoacid, thereby reducing its concentration and modifying the photoresist surface to improve critical dimension uniformity and reduce T-topping profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography process is used, then the photoresist layer is exposed and developed to form a pattern, but photoacid diffusion occurs resulting in T-topping pattern profiles and non-uniform critical dimensions
Solution Approach 1:
The patent introduces a basic gas treatment step that converts the harmful photoacid diffusion into a beneficial effect. The basic gas reacts with the photoacid to neutralize it, transforming the harmful acidic environment into a controlled chemical reaction that prevents T-topping and improves critical dimension uniformity while maintaining the desired pattern profile
Solution Approach 2:
The basic gas acts as an intermediary substance between the photoacid and the photoresist layer. It mediates the harmful interaction by reacting with photoacid to form a neutral compound, thereby preventing photoacid from causing T-topping pattern profiles and non-uniform critical dimensions during the development process
2Manufacturing precision
If basic gas treatment is applied to react with photoacid, then critical dimension uniformity and resolution are improved, but an additional process step is required
Solution Approach 1:
The patent combines the basic gas treatment step with the existing post-exposure bake (PEB) process by performing both treatments in the same processing chamber. This merging of operations achieves the desired pattern profile improvement while minimizing the increase in process complexity, as the chamber is already heated for PEB and can simultaneously deliver the basic gas treatment
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 method achieves improved critical dimension uniformity and resolution by minimizing photoacid diffusion, resulting in patterned photoresist layers with straight sidewalls and uniform dimensions.
Implementation Method 1
A basic gas is caused flowing over the photoresist layer to react with the photoacid in the photoresist layer
Implementation Method 2
A first region of the photoresist layer is exposed to a radiation to produce photoacid in the photoresist layer
Implementation Method 3
undesirable T-topping pattern profiles and non-uniform critical dimensions due to photoacid diffusion in the photoresist layer
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a photoresist layer over a substrate. A portion of the photoresist layer is exposed, using a mask, to a radiation. The photoresist layer is treated, using a basic gas. The photoresist layer is developed to form a patterned photoresist layer over the substrate.