DNQ-Free Chemically Amplified Resist for Thick-Film Profile Control
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Solution Overview
Problem
Existing photoresist compositions face challenges in thick film applications due to sloped profiles and high costs, while chemically amplified resists suffer from post-exposure delay issues leading to manufacturing defects and low throughput.
Innovation Solution
A hybrid resist formulation combining Novolak-based resins with acetal and tertiary-alkyl protected (meth)acrylate polymers, eliminating diazonaphthoquinone (DNQ) components, which provides high resolution, flexibility across thin and thick films, and reduces post-exposure delay effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional Novolak/DNQ resist platforms are used for thick film applications, then film absorption is improved, but sloped profiles are produced
Solution Approach 1:
The patent uses a composite resist system combining Novolak resin with chemically amplified components (PAG and acid-labile protecting groups). This hybrid approach merges the high absorption characteristics of conventional Novolak/DNQ systems with the enhanced profile control of chemically amplified resists, eliminating the sloped profile issue while maintaining thick film performance
Solution Approach 2:
The invention changes the chemical parameters of the resist system by introducing acid-labile protecting groups that can be selectively removed through photoacid generation. This parameter change enables controlled dissolution rates that produce vertical profiles even in thick films, overcoming the limitations of conventional systems
2Manufacturing precision
If positive chemically amplified resists with high activation energy protecting groups are used, then resolution is improved, but post exposure delay sensitivity increases causing T-topping
Solution Approach 1:
The patent applies different types of acid-labile protecting groups at different locations within the resist system. By using a mixture of protecting groups with different activation energies, the system achieves both high resolution (through the high activation energy groups) and reduced PED sensitivity (through the low activation energy groups that prevent acid depletion effects)
Solution Approach 2:
The resist composition combines multiple protecting group types with different acid cleavage characteristics. This composite approach creates a synergistic effect where the diverse protecting groups compensate for each other's weaknesses, eliminating T-topping while maintaining resolution
3Length of stationary object
If conventional chemically amplified resists are used for thick films, then film thickness performance is improved, but cost increases
Solution Approach 1:
The patent segments the resist system into distinct functional components: Novolak resin (cost-effective base), PAG (photoacid generator), and acid-labile protecting groups. This segmentation allows the use of inexpensive Novolak resin as the primary binder while adding only the necessary minimal amounts of chemically amplified components to achieve thick film performance, thereby controlling costs
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 hybrid resist composition offers cost-effective, high-resolution photoresists with extended post-exposure delay latitude, minimizing defects and enhancing manufacturing throughput.
Implementation Method 1
the catalytic acid is formed by photodecomposition of a photo-acid generator (PAG) component
Implementation Method 2
a base soluble resin, usually a phenolic resin or (meth)acrylate resin, is released in areas of the resist exposed to radiation, rendering it aqueous base developable, by an acid catalyzed cleavage of protecting groups on these resins
Implementation Method 3
The coated substrate is next subjected to an image-wise exposure to imaging radiation. This radiation exposure causes a chemical transformation in the exposed areas of the coated surface
Data Source
AI summary
The disclosed subject matter relates to resist compositions that include: (A) an acetal functionalized acrylic polymer component comprising repeat units selected from ones having structure (1), (2), (3), (4), (5), (6), and (7); (B) a tert-alkyl functionalized acrylic polymer component comprising repeat units selected from ones having structure (1a), (2a), (3a), (4a), (5a), (6a), and (7a); (C) a phenolic resin component comprising a Novolak-based resin; (D) a photo acid generator (PAG) component and (E) a solvent component where the resist compositions does not include a diazonaphthoquinone (DNQ) component.