Rinse Solution for Pattern Formation
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Solution Overview
Problem
The challenge in pattern formation for LSI devices is the occurrence of pattern collapse during the rinsing and drying process, which is not adequately addressed by existing methods, especially for fine feature sizes, as they fail to minimize interfacial stress effectively.
Innovation Solution
A rinse solution comprising a heat/acid-decomposable polymer and water is used to fill spaces between resist pattern features, which is then decomposed by heating, eliminating the risk of pattern collapse without applying stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water rinsing is used after alkaline development, then developer is removed from resist pattern, but interfacial stress causes pattern collapse during spin drying
Solution Approach 1:
The patent introduces a surfactant as an intermediary substance in the rinse solution that mediates between the water and the resist pattern. The surfactant reduces surface tension and interfacial stress at the boundary between liquid and resist pattern, preventing pattern collapse during drying while still allowing effective developer removal.
Solution Approach 2:
The patent changes the physical-chemical parameters of the rinse solution by adding surfactants that modify surface tension properties. This parameter change allows the solution to wet the resist pattern effectively for developer removal while reducing the harmful interfacial stress that causes pattern collapse during subsequent drying.
2Object-affected harmful factors
If surfactant is added to rinse solution, then interfacial stress is reduced, but pattern collapse prevention is still insufficient
Solution Approach 1:
The patent creates a composite rinse solution system combining multiple components: water, surfactants for surface tension control, and polymers that form protective films. This composite approach provides synergistic effects where the polymer layer offers additional mechanical support and stress distribution beyond what surfactants alone can achieve, thereby sufficiently preventing pattern collapse.
Solution Approach 2:
The patent applies a protective polymer coating to the resist pattern before the drying process. This beforehand cushioning layer acts as a buffer that distributes and absorbs the interfacial stress during spin drying, preventing direct stress transmission to the delicate resist pattern features and avoiding collapse.
3Reliability
If freeze drying with supercritical carbon dioxide is used, then pattern collapse is prevented, but throughput is reduced due to sequential chamber processing
Solution Approach 1:
The patent enables the rinse solution itself to provide the protective function that would otherwise require a separate freeze drying process. The polymer-containing rinse solution dries autonomously in ambient conditions, with the polymer forming a protective film that prevents collapse, eliminating the need for specialized high-pressure chambers and sequential processing.
Solution Approach 2:
The patent replaces the complex mechanical system of supercritical fluid freeze drying with a simple chemical solution approach. Instead of using high-pressure carbon dioxide chambers and phase transition mechanics, the invention uses a chemically formulated rinse solution with polymers that provides equivalent protection during conventional ambient drying, dramatically simplifying the process and enabling parallel 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
This approach enables the formation of fine feature size patterns with minimized collapse, facilitating high-throughput processing and mass productivity in pattern formation.
Implementation Method 1
a heat/acid-decomposable polymer... which is then decomposed by heating
Data Source
AI summary
In a resist pattern forming process, a rinse solution comprising (A) a heat/acid-decomposable polymer and (B) water is effective. The pattern forming process using the rinse solution is successful in forming fine feature size patterns while minimizing the occurrence of pattern collapse. High-throughput processing is possible.