KrF Positive Photoresist Composition for Clean Fine Patterning
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Solution Overview
Problem
Conventional KrF positive photoresists suffer from limited resolution, vertical profile issues, and residual scum under patterns, making them inadequate for ultra-fine semiconductor manufacturing.
Innovation Solution
A chemically amplified positive photoresist composition for KrF lasers incorporating an under-pattern acid generating aid monomer additive with specific molecular weights and formulations, enhancing pattern profile and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional KrF positive photoresist is used, then the manufacturing process is simple, but the resolution and pattern profile are insufficient for ultra-fine patterns
Solution Approach 1:
The patent uses a composite photoresist system combining polyhydroxystyrene base resin with specific acid generating aids (sulfonium salts, carboxylic acid derivatives) and chain transfer agents. This composite formulation enables KrF laser compatibility with improved resolution by integrating multiple functional components that work synergistically to achieve both pattern fidelity and chemical amplification.
Solution Approach 2:
The patent optimizes molecular weight parameters of the photoresist components, specifically using polyhydroxystyrene with weight-average molecular weight of 5,000-50,000 and number-average molecular weight of 2,000-20,000. This parameter control enables better pattern resolution while maintaining film integrity and etch resistance during semiconductor manufacturing.
2Productivity
If photoresist film thickness is reduced for higher-density integration, then the pattern density increases, but the etching resistance and pattern profile deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the molecular weight distribution of polyhydroxystyrene (weight-average MW: 5,000-50,000, number-average MW: 2,000-20,000) and optimizing the thickness of the photoresist film. This enables the formation of ultra-fine patterns with maintained etching resistance even at reduced film thicknesses required for higher-density integration.
3Manufacturing precision
If conventional photoresist composition is used, then the formulation is simple, but residual scum remains under the pattern
Solution Approach 1:
The patent extracts and addresses the specific problem of residual scum formation by incorporating chain transfer agents (compounds with formulas 1-3) into the photoresist composition. These agents specifically target and eliminate scum formation under patterns while maintaining the overall simplicity of the base resin system.
Solution Approach 2:
The patent introduces acid generating aids and chain transfer agents as intermediary substances that mediate between the photoresist base and the development process. These intermediaries facilitate complete pattern formation by preventing scum formation and ensuring clean pattern edges during the chemically amplified positive photoresist process.
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 achieves improved sensitivity, resolution, and vertical profile with reduced residual scum, providing wider process margins for semiconductor manufacturing.
Implementation Method 1
a photoresist composition includes a photo acid generator that generates acid when irradiated with an excimer laser
Implementation Method 2
chemically amplified positive photoresist composition
Data Source
AI summary
The present disclosure relates to a chemically amplified positive photoresist composition for improving a pattern profile and resolution. The chemically amplified positive photoresist composition is characterized by including, based on the total weight of the composition, 5 to 60 wt % of a polymer resin, 0.1 to 5 wt % of an under-pattern acid generating aid monomer additive represented by Formula 1 to Formula 3, 0.05 to 10 wt % of a photo acid generator, 0.01 to 5 wt % of an acid dispersion inhibitor, and the remainder of a solvent. The chemically amplified positive photoresist composition provides an improved vertical profile and improved resolution and sensitivity compared to conventional positive photoresists and does not generate residual scum. Thus, the chemically amplified positive photoresist composition has excellent process margins.