Antireflective Coating Composition for Photoresist Stability
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to challenges in photolithography, including thin film interference and reflective notching due to back reflection from highly reflective substrates, which result in line width variations and photoresist loss, and existing antireflective coatings can form defects during storage and transportation.
Innovation Solution
An antireflective coating composition comprising a polymeric crosslinker and a solvent mixture with specific organic solvents, which is substantially free of defects and has a low particle count after accelerated aging, ensuring stability and preventing particle formation during storage and transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antireflective coating compositions are used, then lithographic performance is improved by reducing back reflection, but coating defects form during storage and transportation
Solution Approach 1:
The patent changes the chemical composition parameters of the antireflective coating by incorporating specific additives including chelating agents (e.g., EDTA, DTPA), antioxidants (e.g., BHT, BHA), and stabilizers. These compositional modifications prevent degradation reactions during storage while maintaining the coating's antireflective properties and lithographic performance.
Solution Approach 2:
The patent introduces intermediary substances such as chelating agents that bind to metal ions and prevent catalytic degradation, and antioxidants that intercept free radicals before they can cause polymer degradation. These intermediaries protect the coating system from degradation pathways without interfering with the coating's primary function.
2Manufacturing precision
If the photoresist is patterned over reflective substrates with topographical features, then miniaturization is achieved, but reflective notching causes line width variations and photoresist loss
Solution Approach 1:
The patent converts the harmful back-reflected light into a beneficial effect by adding radiation-absorbing components to the antireflective coating. These components absorb the reflected radiation at wavelengths matching the photoresist sensitivity, preventing notching while allowing the coating to maintain its protective function. The harmful reflection is transformed into useful radiation absorption.
Solution Approach 2:
The patent creates a composite antireflective coating system that combines multiple functional components: polymers for film formation, crosslinkers for adhesion and stability, radiation-absorbing additives for preventing notching, and stabilizers for storage durability. This composite structure addresses multiple requirements simultaneously.
3Manufacturing precision
If thin film interference effects occur due to back reflection, then lithographic processing is complicated, but critical line width dimensions vary
Solution Approach 1:
The patent addresses thin film interference by incorporating radiation-absorbing additives that selectively absorb reflected light at wavelengths where the photoresist is sensitive. This converts the interfering reflected radiation into absorbed energy, eliminating the standing wave patterns that cause line width variations without adding process complexity.
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 effectively reduces defects and maintains stability, improving lithographic performance by minimizing line width variations and photoresist loss, while ensuring low particle counts to prevent yield loss in semiconductor device manufacturing.
Implementation Method 1
Solvents that prevent insoluble materials from forming in the composition or in the coating are highly desirable
Implementation Method 2
Absorbing antireflective coatings in photolithography are used to diminish problems that result from back reflection of light from highly reflective substrates
Implementation Method 3
a thin coating of film of a photoresist composition is first applied to a substrate material
Data Source
AI summary
The invention relates to an antireflective coating composition capable of being coated beneath a photoresist layer, where the antireflective coating composition comprises a polymeric crosslinker and a solvent mixture, where the solvent mixture comprises at least one primary organic solvent and at least one secondary organic solvent selected from any of structures 1, 2 and 3, Formula (I) (II) (III) where, R1, R3, and R4, are selected from H and C1-C6alkyl, and R2, R5, R6, R7, R8, and R9 are selected from C1-C6alkyl, and n=1 -5. The invention also relates to an antireflective coating composition capable of being coated beneath a photoresist layer, where the antireflective coating composition comprises a polymeric crosslinker and a solvent mixture, where the solvent mixture comprises at least 2 organic solvents, and where the antireflective coating composition has a liquid particle count at 0.2 micron of less than 100/ml after accelerated aging.