Chemically-Amplified Resist Composition for Low Line Edge Roughness
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Solution Overview
Problem
Current photoresist technologies face challenges in achieving high resolution and low line edge roughness for semiconductor manufacturing, particularly for pattern rules of 45 nanometers or less, where existing solutions either compromise on resolution or suffer from scum formation and pattern profile deterioration.
Innovation Solution
A chemically-amplified positive resist composition using a base polymer with a weight-average molecular weight of 4,000 to 7,000, specifically 4,500 to 5,500, comprising monomer units such as styrene and indene or acenaphthylene units, with a phenolic hydroxyl group protected by an acid-labile acetal group, to achieve high resolution and reduced line edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a base polymer with high molecular weight (Mw ≥ 10,000) is used in a photo resist, then the resist pattern shows good dissolution properties, but scum formation occurs due to re-adhering of dissolved polymer
Solution Approach 1:
The patent applies parameter changes by precisely controlling the weight-average molecular weight of the base polymer to be 4,000 to 7,000 (specifically 4,500 to 5,500), which is lower than conventional values. This molecular weight optimization resolves the contradiction by preventing scum formation while maintaining adequate dissolution properties, as the lower molecular weight reduces polymer re-adhesion tendency while the specific range ensures proper film formation and dissolution control.
2Object-generated harmful factors
If a base polymer with low molecular weight (Mw ≤ 5,000) is used in a photo resist, then scum formation is reduced, but the resist pattern shows round head instead of rectangular head
Solution Approach 1:
The patent resolves this contradiction by optimizing the molecular weight parameter to a specific range of 4,000 to 7,000 (specifically 4,500 to 5,500), which is higher than the ≤5,000 value that causes round heads. This optimized range provides sufficient polymer chain length for proper pattern profile formation while maintaining low enough molecular weight to prevent scum formation, thus achieving both rectangular head patterns and scum-free surfaces.
3Ease of manufacture
If conventional photo resist materials are used for pattern rules of 45 nanometers or less, then manufacturing process is simple, but resolution and line edge roughness are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the base polymer molecular weight to 4,000 to 7,000 (specifically 4,500 to 5,500), which enables achievement of 65 nanometers or less pattern rules with excellent line edge roughness. This molecular weight optimization improves resolution and pattern precision while maintaining manufacturing simplicity, as it works with conventional chemically-amplified resist mechanisms and standard fabrication processes.
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 composition enables the formation of fine resist patterns with excellent line edge roughness and high reliability for semiconductor manufacturing, particularly for pattern rules of 65 nanometers or less, improving both resolution and pattern precision without scum formation.
Implementation Method 1
a phenolic hydroxyl group protected by an acid-labile acetal group
Implementation Method 2
a chemically-amplified positive resist composition
Data Source
Figure 1
AI summary
There is disclosed a resist patterning process with a minimum line width of 65 nanometers or less may be formed by using a resist composition containing a polymer, as a base polymer of a chemically-amplified resist composition, composed of a styrene unit whose hydroxyl group is protected by an acid labile group, and an indene unit, and/or an acenaphthalene unit, wherein the polymer has the weight-average molecular weight of 4,000 to 7,000, and in particular, 4,500 to 5,500.One of the currently existing problems to be solved is the line edge roughness. To solve this problem by an acid-generator and a basic compound, there is a problem of the trade-off relationship with a resolution power. There can be provided a resist composition having a high resolution containing a base polymer such as hydroxystyrene that is protected by an acid labile group, a resist patterning process with a pattern rule of 65 nanometers or less having a reduced line edge roughness.