Amorphous Bismuth Anion Exchanger for Electronic Sealing
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Solution Overview
Problem
Conventional resin compositions for electronic component sealing, particularly those using epoxy resins, face challenges with large particle sizes of inorganic ion exchangers that hinder infiltration into confined chip areas, and crystalline bismuth oxide exhibits lower ion exchange rates and capacities compared to amorphous forms, necessitating a more effective and smaller particle-sized amorphous bismuth compound for enhanced sealing performance.
Innovation Solution
The development of an amorphous inorganic anion exchanger with a specific particle size range and high ion exchange capacity, produced through a process involving a precipitate formation step at controlled pH and temperature, followed by washing and drying, to create microparticles with low nitrate content, which can be incorporated into resin compositions for improved sealing efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional inorganic ion exchangers with large particle sizes are used, then ion exchange capacity is sufficient, but infiltration into confined chip areas is hindered
Solution Approach 1:
The invention segments the inorganic ion exchanger into ultra-fine particles with a maximum particle size of 5 μm or less, preferably 1 μm or less. This segmentation enables the particles to infiltrate confined areas within semiconductor chips while maintaining sufficient ion exchange capacity, directly resolving the contradiction between particle size and infiltration capability.
2Reliability
If crystalline bismuth oxide is used, then water resistance is good, but ion exchange rate is lower compared to amorphous bismuth oxide
Solution Approach 1:
The invention changes the structural parameter of bismuth oxide from crystalline to amorphous form. This parameter change dramatically increases the ion exchange rate while the controlled particle size and composition maintain adequate water resistance, resolving the contradiction between ion exchange rate and water resistance.
3Reliability
If bismuth compound with high nitrate content is used, then ion exchange capacity is improved, but water resistance deteriorates
Solution Approach 1:
The invention optimizes the nitrate content parameter to within 0-10 wt% of the total composition. This parameter optimization maintains sufficient ion exchange capacity while preventing water resistance deterioration, resolving the contradiction between ion exchange capacity and water resistance.
4Strength
If epoxy resin is used for sealing, then adhesion to metal wiring and heat resistance are good, but ionic impurities cause corrosion of metal wiring
Solution Approach 1:
The invention introduces an inorganic anion exchanger as an intermediary substance mixed into the epoxy resin composition. This intermediary captures and removes ionic impurities from the resin system, preventing corrosion of metal wiring while preserving the excellent adhesion and heat resistance properties of the epoxy resin.
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 resulting amorphous bismuth compound demonstrates superior ion exchangeability and corrosion prevention capabilities, suitable for sealing electronic components with narrow pitches or thin coatings, enhancing reliability and preventing metal wiring corrosion within electronic devices.
Implementation Method 1
an epoxy resin composition for semiconductor sealing formed by mixing an epoxy resin with a bismuth compound, which is an inorganic anion exchanger
Implementation Method 2
a process for producing an amorphous bismuth compound, comprising a precipitate formation step of forming a precipitate by subjecting an acidic aqueous solution comprising trivalent Bi ions to a temperature in the range of higher than 0° C. but less than 20° C. and a pH of at least 12
Data Source
AI summary
The amorphous inorganic anion exchanger of the present invention is represented by Formula (1) and has an average primary particle size observed with an electron microscope of at least 1 nm but no greater than 500 nm and an NO3 content of no greater than 1 wt % of the whole:BiO(OH) Formula (1).