Photocurable Epoxy Resin for Rugged Substrate Coating
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Solution Overview
Problem
Current photocurable resin compositions face challenges in achieving even coating on rugged substrates, leading to gaps and defects, and struggle with flexibility, adhesion, and transparency, especially in high-aspect-ratio structures and thick films, which affects their reliability and sensitivity in electronic part protection and substrate lamination.
Innovation Solution
A photocurable resin composition incorporating an epoxy group-containing polymer compound with specific molecular weight and a photoacid generator, capable of crosslinking under various wavelengths, is developed, along with a dry film and pattern forming method, to enhance film thickness uniformity, adhesion, and sensitivity, while minimizing internal stress and light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spin coating method is used to apply photocurable resin composition, then wide range of film thickness can be achieved, but coating uniformity deteriorates on rugged substrates due to gaps and voids at step portions
Solution Approach 1:
The patent changes the viscosity parameter of the photocurable resin composition by selecting specific epoxy resins with appropriate molecular weights and structures. This parameter adjustment enables the resin to flow into and fill rugged substrate features while maintaining coating uniformity, resolving the contradiction between adaptability to different thicknesses and manufacturing precision on rugged surfaces
Solution Approach 2:
The patent employs a composite photocurable resin composition combining multiple epoxy resins with different characteristics (viscosity, molecular weight, functional groups) and compatible curing agents. This composite formulation achieves both wide film thickness range and excellent coating uniformity on rugged substrates by balancing flowability and structural integrity
2Ease of manufacture
If spraying method is used as alternative applying method, then application process is simplified, but film defects increase including height differences, film interruption, and pinholes
Solution Approach 1:
The patent optimizes the viscosity parameter of the photocurable resin composition to a specific range that enables smooth spraying application without generating defects. The controlled viscosity ensures proper atomization and uniform deposition, maintaining high film quality while simplifying the application process
Solution Approach 2:
The patent formulates the resin composition with local quality considerations, ensuring that the material properties are optimized for spraying application at the point of deposition. The composition maintains appropriate rheological characteristics that prevent film interruption and pinhole formation during the spraying process
3Length of stationary object
If high viscosity composition is used for spraying to obtain required film thickness, then film thickness is achieved, but planarization and step coverage problems persist
Solution Approach 1:
The patent precisely controls the viscosity parameter within an optimal range rather than using high viscosity. This parameter optimization allows the composition to achieve required film thickness through spraying while maintaining excellent planarization and step coverage, as the resin flows properly to fill substrate features without being too thick
4Strength
If photocurable resin composition with good adhesion is used, then substrate bonding is improved, but internal stress increases reducing flexibility in lamination
Solution Approach 1:
The patent uses a composite formulation combining multiple epoxy resins and curing agents that work synergistically. This composite approach achieves strong adhesion to substrates while the specific composition balance minimizes internal stress during curing, maintaining flexibility for lamination applications
Solution Approach 2:
The patent adjusts the chemical composition parameters, including epoxy resin molecular weight, functional group types, and curing agent ratios, to optimize the balance between adhesion strength and internal stress. This parameter optimization ensures both strong substrate bonding and low internal stress for flexible lamination
5Length of stationary object
If thick film is formed to provide adequate protection, then protective function is enhanced, but light absorption increases lowering sensitivity and causing exposure energy difference between surface and bottom
Solution Approach 1:
The patent optimizes the optical and rheological parameters of the photocurable resin composition. By selecting epoxy resins with appropriate transparency and controlling the formulation, the composition achieves adequate film thickness for protection while maintaining high light transmission, ensuring uniform sensitivity and exposure energy distribution from surface to bottom
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 enables fine pattern formation with excellent verticality and adhesion on rugged surfaces, providing high reliability as an insulating protective film with improved heat resistance and mechanical characteristics, suitable for electronic parts and substrate bonding.
Implementation Method 1
a photoacid generator represented by the general formula (8) and capable of generating an acid through decomposition, particularly, under radiations with a wavelength of 190 to 500 nm
Implementation Method 2
an epoxy group-containing polymer compound having repeating units represented by the general formula (1)... capable of crosslinking under various wavelengths
Data Source
AI summary
A photocurable composition includes:(A) an epoxy group-containing polymer compound having repeating units represented by the following formula (1),where R1 to R4 are each a hydrocarbon group, m is an integer of 1 to 100, a, b, c and d are each 0 or a positive number, such that 0<(c+d)/(a+b+c+d)≦1.0, and X and Y are each the formula (2) or (3), provided that at least one group of the formula (3) is present,(B) a photoacid generator represented by the formula (8) and(C) a solvent.