Halogen-Containing Resist Underlayer Coating Composition for Mask Blank
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Solution Overview
Problem
Chemically-amplified type resist coatings used in mask production suffer from shape defects and reduced resolving power due to inadequate adherence between the resist coating and the base layer, leading to poor patterning and etching performance.
Innovation Solution
A resist underlayer coating forming composition containing a polymer compound with a halogen atom-containing repeating structural unit and a solvent is used, which enhances adherence and etching rates, preventing acid deactivation and maintaining high resolving power during patterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a chemically-amplified type resist coating is used, then sensitivity and resolving power are improved, but shape defects occur due to acid deactivation at the interface with the base coating
Solution Approach 1:
The patent introduces an underlayer coating as an intermediary between the base coating (chromium oxide anti-reflective coating) and the chemically-amplified type resist coating. This underlayer prevents direct contact between the resist and the base coating, thereby preventing acid deactivation at the interface while maintaining the high resolving power of the chemically-amplified resist. The underlayer acts as a buffer that allows the acid-catalyzed reaction to proceed properly without being suppressed by the base coating.
2Reliability
If an inorganic coating of silicide materials or organic anti-reflective coating is introduced as a base coating, then shape defects are resolved, but the resolving property of patterning is lowered due to the influence of the resist underlayer coating
Solution Approach 1:
The patent carefully controls the parameters of the underlayer coating, including its thickness (optimized to prevent acid deactivation while minimizing interference with patterning), composition (specific polymer compounds with controlled molecular weight and functional groups), and crosslinking density. By optimizing these parameters, the underlayer provides sufficient protection against acid deactivation while maintaining high resolving property in the resist pattern.
3Measurement precision
If the accelerating voltage of electron beam is increased to 50 eV or more, then forward scattering is reduced and beam convergence is improved, but the resist occurs shortage of sensitivity
Solution Approach 1:
The patent employs a composite structure consisting of the base coating, underlayer coating, and chemically-amplified resist coating. This composite system is specifically designed to work with high-energy electron beams (50 eV or more). The underlayer coating in particular contains polymer compounds with functional groups that enhance sensitivity to high-energy electron beams, allowing the resist to maintain adequate sensitivity even when using accelerated electron beams for improved beam convergence and reduced forward scattering.
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 resist underlayer coating composition improves the adherence between the resist and base coatings, reduces shape defects, and maintains high resolving power, enabling effective patterning and etching without inhibiting acid-catalyzed reactions.
Implementation Method 1
Patent Document 2 discloses an anti-reflective coating forming composition comprising a polymer material containing halogen atom for forming an anti-reflective coating that strongly absorbs a light at wavelength 157 nm
Implementation Method 2
the resist underlayer coating having a relatively high dry etching rate and a function of preventing diffusion of acid generated in a resist coating
Data Source
AI summary
There is provided a resist underlayer coating forming composition used in processes for manufacturing a mask blank and a mask, and a mask blank and a mask manufactured from the composition. The resist underlayer coating forming composition comprises a polymer compound having a halogen atom-containing repeating structural unit and a solvent. In a mask blank including a thin film for forming transfer pattern and a chemically-amplified type resist coating on a substrate in that order, the composition is used for forming a resist underlayer coating between the thin film for forming transfer pattern and the resist coating. The polymer compound is preferably a compound containing a halogen atom in an amount of at least 10 mass %.