Photoimageable Bottom Antireflective Coating for Aqueous Development
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Solution Overview
Problem
Existing antireflective coatings in photolithography require dry etching, which can damage substrates and is costly, and do not effectively support the miniaturization of semiconductor devices due to limitations in etch rate and lithographic performance.
Innovation Solution
A novel aqueous developable antireflective coating composition that uses a crosslinking compound and nonmiscible polymers, allowing for photoimageable and soluble properties in an alkaline solution, eliminating the need for dry etching and enabling simultaneous development with photoresist patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dry etching is used to remove antireflective coatings, then the coating can be removed, but substrate damage occurs and processing cost increases
Solution Approach 1:
The patent changes the chemical parameters of the antireflective coating by incorporating base-soluble polymer components and base-labile crosslinking agents. This allows the coating to be removed via chemical dissolution in aqueous alkaline solutions rather than physical sputtering, eliminating substrate damage while maintaining effective coating removal
Solution Approach 2:
The patent replaces the mechanical/physical dry etching process with a chemical wet development process. The antireflective coating is designed to be soluble in aqueous alkaline developers, substituting the mechanical sputtering mechanism with chemical dissolution, thereby removing the harmful mechanical impact on the substrate
2Ease of manufacture
If dry etching is used to remove antireflective coatings, then the coating can be removed, but processing cost increases
Solution Approach 1:
The patent merges the antireflective coating removal step with the photoresist development step by designing the coating to be soluble in the same aqueous alkaline developer used for photoresist. This combines two separate processing steps into one, reducing overall processing cost and time while maintaining effective coating removal
Solution Approach 2:
The patent employs conventional, cost-effective aqueous alkaline developer solutions (such as TMAH-based developers) rather than expensive specialized dry etching chemicals or equipment. This uses inexpensive, readily available materials to achieve the coating removal function
3Ease of manufacture
If the antireflective coating is made soluble in aqueous alkaline solution, then dry etching is eliminated, but the coating must be designed with specific polymer composition
Solution Approach 1:
The patent uses composite polymer materials comprising base-soluble polymers (such as polyhydroxystyrene, polyacrylic acid, polyacrylamide) combined with base-labile crosslinking agents. This composite structure provides both the required aqueous alkaline solubility for simplified processing and the necessary coating performance characteristics
Solution Approach 2:
The patent segments the coating composition into distinct functional components: base-soluble polymer matrices for developer accessibility, base-labile crosslinking agents for controlled solubility activation, and antireflective agents for optical performance. This segmentation allows each component to be optimized independently while working together to achieve overall coating functionality
4Productivity
If the antireflective coating and photoresist are developed simultaneously, then processing steps are reduced, but the coating must be imageable in the same developer as photoresist
Solution Approach 1:
The patent designs the antireflective coating to perform multiple functions: providing antireflective optical performance, enabling photopatterning through photoacid generator incorporation, and ensuring solubility in the same aqueous alkaline developer as photoresist. This multi-functionality allows simultaneous development while maintaining all required coating performances
Solution Approach 2:
The patent uses photoacid generators as intermediaries that, upon UV exposure, generate acid to trigger base-labile deprotection reactions in the coating. This intermediary mechanism enables the coating to respond to UV exposure and become soluble in aqueous alkaline developer, facilitating simultaneous imaging with photoresist
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
This solution simplifies the lithographic process, reduces substrate damage, and enhances the delineation of photoresist images by allowing the antireflective coating to be removed in an aqueous alkaline solution, improving the precision and cost-effectiveness of semiconductor fabrication.
Implementation Method 1
at least one photoacid generator... which upon exposure to a wavelength of light used to expose a positive photoresist forms an acid
Implementation Method 2
a crosslinking compound... wherein the antireflective coating is crosslinked
Data Source
AI summary
The invention relates to a photoimageable antireflective coating composition capable of forming a pattern by development in an aqueous alkaline solution, comprising, (i) a polymer A soluble in a coating solvent and comprises a chromophore, a crosslinking moiety, and optionally a cleavable group which under acid or thermal conditions produces a functionality which aids in the solubility of the polymer in an aqueous alkaline solution and; (ii) at least one photoacid generator; (iii) a crosslinking agent; (iv) optionally, a thermal acid generator; (v) a polymer B which is soluble in an aqueous alkaline solution prior to development, where polymer B is non-miscible with polymer A and soluble in the coating solvent, and; (vi) a coating solvent composition, and (vii) optionally, a quencher. The invention also relates to a process for imaging the antireflective coating.