Basic Aqueous Rinse for Lithography Resist Pattern Integrity
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Solution Overview
Problem
Current lithography techniques, particularly positive tone development (PTD) and negative tone development (NTD) processes, face challenges in achieving sufficient resist pattern contrast and structural integrity due to issues like resist pattern swelling, deformation, collapse, and peeling, especially as technology nodes shrink.
Innovation Solution
The introduction of a basic aqueous rinse solution in the lithography process, which increases the deprotonating ability and reduces residues in the resist layer, thereby improving resist pattern solubility and reducing deformation issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PTD or NTD processes are used, then development function is achieved, but resist pattern structural integrity deteriorates (deformation, collapse, peeling)
Solution Approach 1:
The patent changes the chemical parameters of the rinse solution by adjusting pH to be greater than 7 (basic condition) and controlling base concentration between 0.1-10%. This parameter change prevents resist pattern deformation, collapse, and peeling while maintaining development function, directly resolving the contradiction between structural integrity and manufacturing precision
Solution Approach 2:
The patent applies preliminary anti-action by using a basic rinse solution before final resist pattern formation to prevent protonation of carboxyl groups. This preliminary treatment counteracts potential harmful effects on resist pattern structure before they can occur, maintaining both structural integrity and dimensional accuracy
2Object-generated harmful factors
If aqueous-based rinse solution is used, then rinsing function is achieved, but resist pattern residues increase due to protonation
Solution Approach 1:
The patent changes the pH parameter of the rinse solution to greater than 7 (basic condition), which prevents protonation of carboxyl groups in the resist material. This parameter change eliminates the formation of water-soluble residues while maintaining accurate critical dimensions, directly resolving the contradiction between reducing harmful factors and maintaining manufacturing precision
Solution Approach 2:
The patent converts the potentially harmful acidic environment into a beneficial basic environment. By using a basic rinse solution, the patent transforms what would normally be a harmful protonation process into a beneficial deprotonation process that prevents residue formation and maintains pattern integrity
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 approach enhances the structural integrity and contrast of resist patterns, reducing residues and improving the accuracy of critical dimensions in advanced technology nodes, thus addressing the limitations of existing PTD and NTD processes.
Implementation Method 1
The introduction of a basic aqueous rinse solution in the lithography process, which increases the deprotonating ability and reduces residues in the resist layer
Data Source
AI summary
A method includes illuminating radiation to a resist layer over a substrate to pattern the resist layer. The patterned resist layer is developed by using a positive tone developer. The patterned resist layer is rinsed using a basic aqueous rinse solution. A pH value of the basic aqueous rinse solution is lower than a pH value of the developer, and a rinse temperature of rinsing the patterned resist layer is in a range of about 20° C. to about 40° C.