Silphenylene Polymer Photo-Curable Resin for Low-Temperature Curing
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Solution Overview
Problem
Existing photosensitive protective films for semiconductor devices and dielectric films for multilayer printed wiring boards face challenges such as high temperature requirements, susceptibility to oxygen interference, film slimming, limited chemical resistance, and difficulty in forming thick films with fine feature sizes, which affect their reliability and performance.
Innovation Solution
A photo-curable resin composition comprising a silphenylene-bearing polymer with recurring units of specific formula, combined with amino condensates, phenol compounds, and a photoacid generator, which allows for the formation of films with varying thicknesses, including thick films, and provides improved adhesion, heat resistance, and chemical resistance, using a patterning process involving radiation and optional post-exposure heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photosensitive polyimide materials are used requiring imidization treatment above 300°C, then the desired polyimide film is produced, but the underlying substrate cannot withstand high temperatures and interconnecting copper can be oxidized
Solution Approach 1:
The patent changes the chemical structure of the polymer from conventional polyimide to silphenylene-bearing polymer, which fundamentally alters the curing characteristics. This structural modification enables the material to cure at low temperatures (below 200°C) while maintaining the desired film properties, thus resolving the contradiction between achieving high-quality polyimide film and avoiding high temperature damage to substrates and copper interconnections
Solution Approach 2:
The patent creates a composite material system combining silphenylene-bearing polymer with specific crosslinking agents (amino condensates, phenol compounds, or epoxy compounds). This composite approach enables low-temperature curing through photo-initiated crosslinking reactions, achieving both the desired film quality and low processing temperature requirements
2Temperature
If solvent-soluble resins with (meth)acrylic radicals are used to lower post-curing temperature, then post-curing temperature is reduced, but the materials are susceptible to oxygen interference and film slimming during development, making it difficult to improve resolution
Solution Approach 1:
The patent changes the photo-curing mechanism from free-radical polymerization of (meth)acrylic groups to cationic photo-curing of silphenylene structures. This fundamental parameter change in the curing chemistry eliminates susceptibility to oxygen interference and film slimming, enabling high-resolution patterning even at low post-curing temperatures
Solution Approach 2:
The patent introduces a photoacid generator as an intermediary substance that mediates the photo-curing process. The photoacid generator absorbs UV light and generates acid, which then catalyzes the crosslinking reaction of the silphenylene-bearing polymer. This intermediary mechanism enables low-temperature curing without the harmful side effects of direct free-radical polymerization
3Ease of manufacture
If positive compositions with polyimide structure having phenolic hydroxyl radicals are used, then the composition can be developed, but the light transmittance makes it difficult to form thick films in excess of 10 microns
Solution Approach 1:
The patent changes the optical and chemical parameters of the resin system by using silphenylene-bearing polymer with high UV light transmittance. This parameter change enables deep UV penetration through thick films, allowing formation of films exceeding 10 microns in thickness while maintaining pattern definition and development capability
4Temperature
If photosensitive epoxy composition is used that can be cured at low temperatures below 200°C, then low temperature curing is achieved, but the cured coating lacks flexibility and moisture-resistant adhesion
Solution Approach 1:
The patent creates a composite material system combining silphenylene-bearing polymer with crosslinking agents (amino condensates, phenol compounds, or epoxy compounds). This composite structure provides both low-temperature photo-curing capability and enhanced mechanical properties including flexibility and moisture-resistant adhesion, resolving the contradiction between low curing temperature and film reliability
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 solution enables the creation of films with fine feature sizes and enhanced reliability, suitable for protective and dielectric applications, offering good adhesion, heat resistance, and chemical resistance, even at low temperatures, thus addressing the limitations of existing technologies.
Implementation Method 1
a photoacid generator which is decomposed with radiation of 190 to 500 nm to generate an acid
Implementation Method 2
photo-curable resin composition comprising a silphenylene-bearing polymer
Data Source
AI summary
A photo-curable resin composition comprising a silphenylene-bearing polymer having a Mw of 3,000-500,000 can be processed to form patterned films having a widely varying thickness from submicron to more than 20 µm. The cured films have good adhesion to substrates, heat resistance, electrical insulation and chemical resistance.