Chemically Amplified Resist Composition for Copper Substrates
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Solution Overview
Problem
Current chemically amplified positive resist compositions face challenges in achieving high resolution and preventing the footing phenomenon when forming patterns on copper substrates with thick films, especially beyond 10 μm thickness, where the aspect ratio is less than 2 and the pattern profile is not rectangular.
Innovation Solution
A chemically amplified positive resist composition comprising a polymer that becomes soluble in alkaline aqueous solution under acid catalysis, combined with a photoacid generator, carboxylic acid, and a benzotriazole or imidazole compound, which enhances the resolution and prevents footing by improving the pattern profile on copper substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a chemically amplified positive photoresist composition is used for forming patterns on copper substrate, then high sensitivity and high resolution are achieved, but the footing phenomenon occurs and pattern profile deteriorates
Solution Approach 1:
The patent introduces a copper chelating agent as an intermediary substance that specifically binds to copper ions at the substrate interface. This mediator prevents the footing phenomenon by controlling the chemical interaction between the resist and copper substrate, thereby improving pattern profile while maintaining the high resolution enabled by chemically amplified positive photoresist
Solution Approach 2:
The patent modifies the chemical composition parameters of the photoresist by adding specific compounds (copper chelating agent, surfactant, and/or basic compound) to change the chemical environment at the copper interface. This parameter change prevents copper ion migration and footing, thereby improving pattern profile without sacrificing resolution
2Length of stationary object
If the thickness of resist film is increased beyond 10 μm, then the film can cover the substrate adequately, but the pattern on copper substrate can no longer be resolved
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist system by incorporating copper chelating agents and other additives that improve chemical uniformity and acid diffusion control. These parameter changes enable thick films (>10 μm) to maintain adequate copper ion suppression and pattern resolution throughout the entire film thickness
3Length of stationary object
If a thick resist film of more than 10 μm is formed on copper substrate, then adequate coverage is achieved, but the aspect ratio becomes less than 2 and footing phenomenon occurs
Solution Approach 1:
The copper chelating agent acts as an intermediary that specifically targets copper ion migration at the substrate interface. By binding copper ions, it prevents the footing phenomenon that would otherwise occur in thick films, thereby maintaining the required aspect ratio of at least 2 even when film thickness exceeds 10 μm
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 achieves high resolution with an aspect ratio of at least 2 and forms rectangular patterns even in thick films, effectively addressing the limitations of existing technologies by ensuring improved pattern shape and stability near the substrate.
Implementation Method 1
a chemically amplified positive resist composition comprising (A) a polymer adapted to turn soluble in alkaline aqueous solution under the action of acid, (B) a photoacid generator
Implementation Method 2
a polymer adapted to turn soluble in alkaline aqueous solution as a result of an acid labile group being eliminated under acid catalysis
Implementation Method 3
a chemically amplified positive resist composition comprising (A) a polymer adapted to turn soluble in alkaline aqueous solution under the action of acid, (B) a photoacid generator, (C) a carboxylic acid, and (D) at least one compound selected from (D-1) a benzotriazole compound and (D-2) an imidazole compound
Data Source
AI summary
A chemically amplified positive resist composition is provided comprising (A) a polymer adapted to tarn soluble in alkaline aqueous solution under the action, of acid, (B) a photoacid generator, (C) a car boxy lie acid, and (D) a benzotriazole compound and/or an imidazole compound. When the resist composition is coated on a copper substrate as a thick film of 5-250 μm thick and lithographically processed into a pattern, a high resolution is available and the pattern is of rectangular profile.