Resist Underlayer Film Tg Control for Wet Etching Stability
Solution Overview
Problem
In the multilayer resist process for semiconductor devices, the resist underlayer film often collapses due to external stimulation during wet etching, as its glass transition temperature is higher than the heating temperature, leading to poor adhesion and removal issues.
Innovation Solution
A resist underlayer film-forming composition with a polymer having a glass transition temperature of 0 to 180°C is used, which includes specific structural units to enhance adhesion and etching resistance, and a silicon-based oxide film is formed on the substrate for wet etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a resist underlayer film-forming composition with high glass transition temperature is used, then the film stability during storage is improved, but the film adhesion to substrate deteriorates and pattern integrity collapses during wet etching
Solution Approach 1:
The patent changes the glass transition temperature parameter of the polymer from high Tg to specifically 0 to 180°C range. This parameter change resolves the contradiction by providing optimal balance: the polymer remains stable during storage while maintaining sufficient adhesion and pattern integrity during wet etching processes.
Solution Approach 2:
The patent uses composite polymer structures including specific structural units (such as vinyl aromatic compounds, cycloolefin compounds, and carboxylic acid groups) to create a resist underlayer film-forming composition that combines both stability and adhesion properties, resolving the contradiction between film stability and adhesion strength.
2Stability of the object's composition
If the glass transition temperature of the resist underlayer film-forming composition is higher than the heating temperature, then the film stability is improved, but the film is removed from the substrate
Solution Approach 1:
The patent optimizes the glass transition temperature parameter to 0 to 180°C, which is lower than conventional high-Tg materials. This allows the film to remain stable during storage and processing while ensuring it does not detach from the substrate during heating and wet etching operations.
3Ease of manufacture
If wet etching is performed after forming the resist film, then the silicon-based oxide film is effectively removed, but the pattern of the resist underlayer film collapses due to external stimulation
Solution Approach 1:
The patent changes the polymer composition parameters to include specific structural units with appropriate Tg (0 to 180°C) and functional groups that provide wet etching resistance. This enables the resist underlayer film to maintain its pattern integrity during wet etching while still allowing effective removal of the silicon-based oxide film.
Solution Approach 2:
The patent converts the potential harmful effect of wet etching (which causes pattern collapse in conventional materials) into a beneficial process by using polymers with specific structural units that are inherently resistant to wet etching, allowing the etching process to effectively remove oxide while preserving 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
The composition ensures excellent adhesion to the substrate and resistance against wet etching, preventing pattern collapse and enabling the formation of finer patterns in semiconductor devices.
Implementation Method 1
a polymer having a glass transition temperature (Tg) of 0 to 180° C.
Data Source
AI summary
A resist underlayer film-forming composition includes a polymer having a glass transition temperature (Tg) of 0 to 180° C. The resist underlayer film-forming composition is used for a multilayer resist process. The multilayer resist process includes forming a silicon-based oxide film on a surface of a resist underlayer film, and subjecting the silicon-based oxide film to wet etching.