Chemically Amplified Resist Patterning for Sub-10nm Resolution
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Solution Overview
Problem
Current pattern formation technologies face challenges in achieving high sensitivity and resolution with low line width roughness (LWR) due to acid diffusion issues in chemically amplified resists, particularly at the 10-nm node and below, where image blur and acid diffusion distance pose limitations.
Innovation Solution
A pattern forming process involving a resist film with recurring units having C4-C6 tertiary alkoxy or alkoxycarbonyl groups as acid labile groups and anion-bound acid generators, which generate polymer backbone-bound acids upon exposure, optionally post-exposure baking at 30 to 70°C, and developing in an alkaline solution to minimize acid diffusion and enhance alkaline solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If chemically amplified resist is used to achieve high sensitivity, then sensitivity is improved, but image blur by acid diffusion occurs and resolution deteriorates
Solution Approach 1:
The patent extracts and removes the acid diffusion problem from the chemically amplified resist system by introducing a non-chemically amplified resist material that does not rely on acid diffusion for pattern formation, thereby eliminating image blur while maintaining sensitivity
Solution Approach 2:
The patent changes the fundamental mechanism parameter from acid diffusion-based chemical amplification to direct photochemical reaction, transforming the resist action mode to eliminate image blur while preserving exposure sensitivity
2Manufacturing precision
If PEB temperature is lowered to reduce acid diffusion distance, then resolution is improved, but deprotection reaction efficiency decreases and sensitivity worsens
Solution Approach 1:
The patent extracts and eliminates the PEB step entirely from the process flow, removing the need to balance temperature parameters for acid diffusion control versus deprotection efficiency, thereby resolving the contradiction between resolution and sensitivity
Solution Approach 2:
The patent performs the deprotection reaction during the exposure step itself rather than requiring a separate PEB step, allowing the reaction to occur at the exposure temperature and eliminating the temperature-time optimization dilemma
3Manufacturing precision
If non-chemically amplified resist material is used to eliminate image blur, then resolution is improved, but sensitivity and contrast become very low
Solution Approach 1:
The patent creates a composite resist system combining the non-chemically amplified resist material with a specific base resin and solvent system that enhances both sensitivity and contrast while maintaining the resolution benefits of eliminating acid diffusion
Solution Approach 2:
The patent optimizes multiple parameters including resist material composition, base resin selection, and solvent system to simultaneously achieve high sensitivity, high contrast, and high resolution in a non-chemically amplified resist system
4Productivity
If pattern feature size is reduced to 10 nm or below, then integration density is improved, but acid diffusion causes image blur and resolution limit is reached
Solution Approach 1:
The patent extracts and eliminates the acid diffusion mechanism from the pattern formation process, removing the fundamental limitation that prevents achieving resolution at 10 nm and below feature sizes
Solution Approach 2:
The patent performs the complete pattern formation action during the exposure step itself, with deprotection occurring immediately upon photoirradiation rather than requiring subsequent thermal diffusion processes, enabling direct formation of sub-10 nm patterns
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 achieves a good balance of sensitivity, resolution, and LWR by reducing acid diffusion, eliminating image blur, and improving dissolution contrast, thereby forming patterns with high resolution and low LWR.
Implementation Method 1
Upon light exposure, the cation-bound acid generator generates a free acid whereas the anion-bound acid generator generates an acid bound to the polymer backbone
Implementation Method 2
it is effective to lower the temperature or to shorten the time of post-exposure bake (PEB) step for incurring deprotection reaction to increase alkaline solubility
Implementation Method 3
A pattern is formed by developing the resist film while omitting PEB
Data Source
AI summary
A pattern having a good balance of sensitivity, resolution and LWR is formed by providing a resist film comprising a base resin comprising recurring units having a C4-C6 tertiary alkoxy or alkoxycarbonyl group as an acid labile group and recurring units capable of generating a backbone-bound acid upon exposure, exposing the resist film to radiation, optionally post-exposure baking the resist film at a low temperature of 30-70° C., and developing the film.