Photosensitive Resin Composition Preventing Aggregate Formation
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Solution Overview
Problem
Current photosensitive resin compositions for dry film resists face challenges such as the formation of aggregates during development, reduced sensitivity, and inadequate resolution and adhesiveness, particularly when exposed to i-line and h-line radiation, which hinders their compatibility and performance in producing high-resolution patterns for printed circuit boards and other semiconductor applications.
Innovation Solution
A photosensitive resin composition comprising a thermoplastic copolymer, an addition polymerizable monomer, a triarylimidazolyl dimer as a photopolymerization initiator, and a pyrazoline compound, specifically formulated to prevent aggregate formation and ensure compatibility with both i-line and h-line radiation, allowing for high sensitivity, resolution, and adhesiveness, and enabling development with aqueous alkali solutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photosensitive resin compositions are used for dry film resists, then the basic photolithography function is achieved, but aggregates form during development causing shorting defects and increased filter replacement frequency
Solution Approach 1:
The patent modifies the chemical composition parameters of the photosensitive resin by incorporating specific copolymers with controlled carboxyl group content (100-600 acid equivalents) and weight-average molecular weight (5,000-500,000), along with addition polymerizable monomers and photopolymerization initiators, to prevent aggregate formation during development while maintaining reliable pattern formation
Solution Approach 2:
The invention creates a composite photosensitive resin composition combining multiple components: copolymer (20-90 wt%), addition polymerizable monomer (5-75 wt%), photopolymerization initiator (0.01-30 wt%), and other additives (0.001-10 wt%), where each component contributes specific properties that collectively prevent aggregate formation while ensuring reliable resist function
2Productivity
If the photosensitive resin composition is optimized for high sensitivity, then shorter exposure times are achieved, but resolution and adhesiveness may be compromised
Solution Approach 1:
The patent optimizes the molecular weight parameters of the copolymer (5,000-500,000) and carboxyl group content (100-600 acid equivalents) to balance sensitivity and resolution, allowing the resin to achieve adequate curing at reduced exposure times while maintaining precise pattern definition through controlled polymerization
3Productivity
If the photosensitive resin composition is optimized for high sensitivity, then shorter exposure times are achieved, but adhesiveness may be compromised
Solution Approach 1:
The invention controls the carboxyl group content (100-600 acid equivalents) and molecular weight (5,000-500,000) of the copolymer to maintain adequate adhesiveness while enabling high sensitivity, ensuring the resist layer adheres properly to the substrate even with reduced exposure times
Solution Approach 2:
The composite formulation combines copolymer, addition polymerizable monomer, and photopolymerization initiator in specific proportions to achieve a balance between sensitivity and adhesiveness, where the synergistic interaction of components ensures both rapid curing and strong substrate bonding
4Reliability
If a protective layer such as polyethylene film is present on the photosensitive resin layer, then the resin is protected during handling, but the protective layer must be released before exposure adding process steps
Solution Approach 1:
The patent employs a disposable protective film that is removed in a single release step before exposure, providing adequate handling protection without requiring complex multi-step removal processes, aligning with the principle of using simple, temporary protective elements
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 excellent compatibility, sensitivity, resolution, and adhesiveness, preventing aggregate formation during development and allowing for effective use in various semiconductor processes, including printed circuit boards, lead frames, and semiconductor packages, with improved performance across different exposure light sources.
Implementation Method 1
the photosensitive resin layer is exposed with ultraviolet rays such as i-line radiation (365 nm) from an ultrahigh pressure mercury lamp through a photomask with a wiring pattern, for polymerization curing of the exposed sections
Data Source
AI summary
[Purpose]To provide a photosensitive resin composition having satisfactory compatibility during dry film formation, exhibiting similar sensitivity for exposure with both i-line radiation and h-line radiation type exposure devices, having excellent resolution and adhesiveness, allowing development with aqueous alkali solutions, and preferably, having no generation of aggregates during development.[Solution Means]A photosensitive resin composition comprising (a) 20-90 wt % of a thermoplastic copolymer having a specific copolymerizing component copolymerized, and having a carboxyl group content of 100-600 acid equivalents and a weight-average molecular weight of 5,000-500,000, (b) 5-75 wt % of an addition polymerizable monomer having at least one terminal ethylenic unsaturated group, (c) 0.01-30 wt % of a photopolymerization initiator containing a triarylimidazolyl dimer, and (d) 0.001-10 wt % of a pyrazoline compound.