Photosensitive Polyimide Resin Adhesion at Low Cure Temperatures
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Solution Overview
Problem
Conventional resin compositions fail to produce a cured film with sufficient adhesiveness, especially when stored at high temperatures, which is crucial for advanced semiconductor packaging like multi-die fan-out wafer level packaging that requires low-temperature curing to protect high-performance dies and ensure yield.
Innovation Solution
A photosensitive resin composition combining a polyimide precursor with a polymerizable unsaturated bond, a polymerizable monomer with an alicyclic skeleton, a photopolymerization initiator, and tetrazole or its derivatives, which allows for high adhesiveness even after storage at elevated temperatures when cured at 200° C or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional resin compositions are used, then the producing process can be simplified by using photosensitive resin, but the cured film does not have sufficient adhesiveness especially after storage at high temperatures
Solution Approach 1:
The patent uses a composite resin composition containing polyimide resin, polybenzoxazole resin, and specific coupling agents (silane coupling agent or titanate coupling agent) to achieve both ease of manufacture through photosensitive processing and high adhesiveness after high-temperature storage. The coupling agents form strong bonds between the resin and substrate, maintaining adhesiveness even after storage at 85°C or higher for extended periods.
Solution Approach 2:
The patent optimizes the molecular weight and chemical structure of the polyimide and polybenzoxazole resins, as well as the type and amount of coupling agents used, to achieve the desired balance between processability and adhesiveness. By carefully selecting parameters such as resin composition ratios and coupling agent concentrations, the cured film maintains high adhesiveness after high-temperature storage while remaining suitable for photosensitive processing.
2Temperature
If low-temperature curing is used to protect high-performance dies and sealing materials, then heat resistance of components is protected, but the cured film may not achieve sufficient crosslinking and adhesiveness
Solution Approach 1:
The patent modifies the chemical composition of the resin system by incorporating specific polyimide and polybenzoxazole resins with appropriate molecular weights and structures, along with coupling agents, to enable effective crosslinking and adhesion formation at low curing temperatures (200°C or lower). This composition optimization allows sufficient crosslinking density to be achieved without requiring high curing temperatures that would damage sensitive components.
Solution Approach 2:
The coupling agents (silane or titanate coupling agents) act as intermediaries between the resin matrix and the substrate, facilitating strong adhesion formation at low curing temperatures. These coupling agents create robust interfacial bonds that compensate for the reduced crosslinking density that would otherwise result from low-temperature curing, thereby maintaining high adhesiveness without damaging sensitive dies or sealing materials.
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 adhesiveness and durability of the cured film under high-temperature and high-humidity conditions, maintaining performance and reliability in electronic components, particularly in semiconductor packaging.
Implementation Method 1
a photopolymerization initiator
Data Source
AI summary
A photosensitive resin composition comprising (A) a polyimide precursor having a polymerizable unsaturated bond; (B) a polymerizable monomer having an alicyclic skeleton; (C) a photopolymerization initiator; and (D) one or more compounds selected from the group consisting of tetrazole and a tetrazole derivative.