Developable Bottom Anti-Reflective Coating for Lithography Scum Prevention
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Solution Overview
Problem
Current bottom anti-reflective coatings used in semiconductor lithography suffer from scum formation and intermixing with photoresist, leading to precision issues and difficulties in pattern formation, especially when exposed to short-wavelength light.
Innovation Solution
A cross-linking agent represented by a specific formula, which reacts with a polymer to form a cross-linking structure, is used to create a bottom anti-reflective coating that is soluble in developing solutions, preventing scum formation and allowing for simultaneous development and removal with the photoresist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a bottom anti-reflective coating is made insoluble in developing solution to prevent intermixing with photoresist, then intermixing is prevented and pattern precision is maintained, but the coating cannot be removed together with photoresist and requires separate dry-etching removal
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of the cross-linking agent to include specific functional groups (carboxylic acid groups with pKa 3-6) that enable the coating to become soluble in developing solutions while maintaining cross-linked structure. This allows the coating to be removed together with photoresist through wet development, eliminating the need for separate dry-etching removal steps.
2Ease of manufacture
If a bottom anti-reflective coating is made soluble in developing solution to be removed together with photoresist, then removal process is simplified, but scum formation occurs during pattern formation
Solution Approach 1:
The patent employs composite materials by creating a cross-linked coating system that combines insoluble cross-linked structure with soluble functional groups. The cross-linking agent contains both cross-linkable groups (for forming insoluble network) and carboxylic acid groups (for providing solubility in developing solution). This composite structure prevents scum formation while enabling simultaneous removal with photoresist.
Solution Approach 2:
The patent applies local quality by creating different functional regions within the coating molecule: the cross-linked backbone provides structural integrity and prevents intermixing, while the carboxylic acid groups provide localized solubility for development. This spatial differentiation of functions allows the coating to maintain precision during patterning while being removable with photoresist.
3Productivity
If short-wavelength light is used for exposure to increase integration degree, then device integration is improved, but standing wave and diffuse reflection problems worsen
Solution Approach 1:
The patent uses the bottom anti-reflective coating as an intermediary layer between the photoresist and substrate. This coating absorbs excess light energy and prevents standing wave formation and diffuse reflection that would otherwise degrade pattern precision during short-wavelength exposure. The coating acts as a mediator that enables high integration exposure while maintaining pattern fidelity.
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 solution enables the formation of a bottom anti-reflective coating that prevents intermixing with the photoresist, maintains pattern precision, and avoids scum formation, allowing for effective pattern formation with both short and long wavelength light exposure.
Implementation Method 1
A cross-linking agent represented by a specific formula, which reacts with a polymer to form a cross-linking structure
Implementation Method 2
it is preferred for the bottom anti-reflective coating to largely absorb radiation used for exposure of the photoresist, to prevent diffuse reflection
Implementation Method 3
casting onto a substrate the above composition for forming a bottom anti-reflective coating, and then heating it
Data Source
AI summary
The present invention provides a cross-linking agent capable of preventing formation of scum from a bottom anti-reflective coating, and also provides a composition for forming a bottom anti-reflection coating containing the agent. The cross-linking agent is a nitrogen-containing aromatic compound having at least one vinyloxy group or N-methoxymethylamide group, and the composition contains the cross-linking agent. The cross-linking agent of the formula (1) can be produced by reaction of a nitrogen-containing aromatic compound, a halogen compound having a vinyloxy group or N-methoxymethylamide group and a basic compound.