Bottom Antireflective Coating Composition for Semiconductor Lithography
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Solution Overview
Problem
Current bottom anti-reflective coatings for semiconductor lithography suffer from intermixing with photoresist layers, leading to precision issues and limited versatility due to their insolubility in alkaline developing solutions, making it difficult to control pattern formation and substrate thickness.
Innovation Solution
A composition comprising a polymer with a condensed polycyclic aromatic group, a maleimide or maleic anhydride derivative, and a solvent, which can be formulated to be either soluble or insoluble in alkaline developing solutions, allowing for controlled solubility and intermixing prevention through a Diels-Alder reaction, enabling the coating to be developed and removed with the photoresist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the bottom anti-reflective coating is made insoluble in photoresist solvents to prevent intermixing, then the coating stability is improved, but the coating cannot be removed together with the photoresist and requires additional dry-etching steps
Solution Approach 1:
The patent introduces a photosensitive group into the polymer structure of the bottom anti-reflective coating, transforming it from a non-photosensitive material to a photosensitive one. This parameter change enables the coating to undergo chemical transformation upon light exposure, allowing it to be dissolved in alkaline developing solutions and removed together with the photoresist, thereby eliminating the need for separate dry-etching steps while maintaining coating stability through controlled crosslinking
2Productivity
If the bottom anti-reflective coating is made soluble in alkaline developing solution to be removed with photoresist, then the manufacturing process is simplified, but the coating may intermix with the photoresist layer causing pattern precision degradation
Solution Approach 1:
The patent applies preliminary crosslinking to the bottom anti-reflective coating through exposure to actinic light before photoresist application. This preliminary action creates a crosslinked network structure that prevents intermixing with the photoresist layer, while the remaining unreacted photosensitive groups allow subsequent dissolution in alkaline developing solutions, enabling both pattern precision maintenance and simplified manufacturing
Solution Approach 2:
The patent creates a composite material system where the bottom anti-reflective coating combines a polymer backbone with both crosslinkable groups (for structural stability and intermixing prevention) and photosensitive groups (for controlled dissolution). This composite structure integrates multiple functions: mechanical stability, intermixing resistance, and selective removability, resolving the contradiction between coating stability and manufacturability
3Stability of the object's composition
If a thermo-crosslinkable composition is used for the bottom anti-reflective coating to prevent intermixing, then the coating stability is improved, but the coating requires dry-etching removal which may damage the photoresist layer
Solution Approach 1:
The patent replaces the mechanical/physical removal method (dry-etching) with a chemical dissolution method. By incorporating photosensitive groups that enable alkaline-soluble crosslinking, the coating can be removed chemically together with the photoresist in the same developing step, eliminating the need for separate dry-etching processes and avoiding photoresist damage while maintaining coating stability through crosslinking
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 prevents intermixing with the photoresist layer, allowing for precise pattern formation with a cross-section perpendicular to the substrate surface and enhances the versatility of photoresist composition selection by enabling the coating to be readily dissolved in alkaline solutions, thus improving lithographic performance.
Implementation Method 1
a polymer having a condensed polycyclic aromatic group which absorbs UV light
Implementation Method 2
a compound having a maleimide or a maleic anhydride
Data Source
AI summary
The present invention provides a composition for forming a bottom anti-reflective coating, and also provides a photoresist pattern formation method employing that composition. The composition gives a bottom anti-reflective coating used in a lithographic process for manufacturing semiconductor devices, and the coating can be developed with a developing solution for photoresist. The composition contains a solvent, a polymer having a condensed polycyclic aromatic group, and a compound having a maleimide derivative or a maleic anhydride derivative. The composition may further contain a photo acid generator or a crosslinking agent.