Polymer Compound for Negative Resist Composition Defect Reduction
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Solution Overview
Problem
Current negative resist compositions for semiconductor and photomask substrates face challenges in achieving high resolution, small line edge roughness (LER), and low temperature dependence, particularly for electron beam lithography, where defects such as radial defects can significantly reduce semiconductor device yield.
Innovation Solution
A polymer compound with specific repeating units, including acid-labile groups and aromatic rings, is used to create a negative resist composition that promotes high resolution, reduces LER, and minimizes defects, incorporating acid generators and diffusion controllers to ensure precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional negative resist compositions are used for electron beam lithography, then pattern formation is achieved, but radial defects occur that reduce semiconductor device yield
Solution Approach 1:
The patent modifies the chemical parameters of the resist composition by incorporating specific polymer compounds with controlled molecular weights, functional group compositions, and structural characteristics. These parameter changes optimize the interaction between the resist and electron beam exposure, preventing radial defect formation while maintaining high pattern fidelity and improving semiconductor device yield.
Solution Approach 2:
The patent employs composite resist compositions that integrate multiple functional components: polymer compounds containing specific repeating units with acid-labile groups, crosslinking agents, and additives. This composite structure synergistically combines pattern formation capability with defect suppression, achieving both high reliability and productivity in electron beam lithography processes.
2Manufacturing precision
If high resolution patterning is pursued, then line edge roughness increases and temperature dependence worsens
Solution Approach 1:
The patent optimizes the molecular weight, functional group composition, and structural parameters of the polymer compound to achieve a balance between resolution and thermal stability. By carefully controlling these parameters, the resist maintains sharp line edges at high resolution while exhibiting reduced temperature dependence, ensuring consistent patterning performance across varying process conditions.
3Ease of operation
If phenol units are used in the polymer for alkali solubility, then dissolution in aqueous alkaline developer is achieved, but transmittance to ArF excimer laser beam is lost
Solution Approach 1:
The patent applies local quality by incorporating acid-labile groups at specific positions within the polymer structure that enable crosslinking only in exposed regions. This localized chemical modification allows the unexposed portions to remain alkali-soluble for easy dissolution, while the exposed portions form insoluble crosslinked structures, achieving both alkali solubility and high light transmittance properties.
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 polymer compound achieves high resolution of 50 nm or less, reduces LER, and minimizes defects, enabling the production of semiconductor devices with improved yield and quality, especially in electron beam lithography.
Implementation Method 1
an acid generator that can decompose by photo-exposure and generate acid
Implementation Method 2
a crosslinking agent that can crosslink the polymer by using the acid as a catalyst and then insolubilize the polymer in the developer
Data Source
Figure 1
AI summary
The present invention provides a polymer compound containing a repeating unit shown by the following general formula (1). There can be provided a polymer compound usable in a negative resist composition that can achieve high resolution of 50 nm or less and small LER and cause very few defects, a negative resist composition using the polymer compound, and a patterning process using the negative resist composition.