Bismuth Compound Anion Exchanger for Semiconductor Encapsulation

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Solution Overview

Problem

Current inorganic anion exchangers used in electronic component encapsulation face challenges such as insufficient anion exchange performance, high moisture absorbency, and thermal instability, which can lead to corrosion and reliability issues, especially with the increasing integration of semiconductors and the use of epoxy resins.

Innovation Solution

A novel bismuth compound represented by the formula Bi(OH)x(NO3)y.nH2O, where x is between 2.5 and 3, y is up to 0.5, and n is 0 or positive, with specific X-ray diffraction peak intensities, is developed, offering improved anion exchange capacity, thermal resistance, and environmental friendliness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional inorganic anion exchangers (hydrotalcites, hydrous bismuth oxide) are used in epoxy resin encapsulation, then anion exchange performance is provided, but moisture absorbency is high and thermal stability is insufficient

Engineering Contradiction:

Improveanion exchange performanceVSAvoidmoisture absorbency and thermal stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical composition parameters of bismuth compounds by controlling the ratio of Bi2O3 to Bi(NO3)3 and the hydration level (n in Bi(OH)x(NO3)y.nH2O), creating a compound with optimized anion exchange capacity while reducing moisture absorbency and improving thermal stability compared to conventional hydrotalcites and hydrous bismuth oxide

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system by combining bismuth oxide, bismuth nitrate, and controlled hydration to form a novel inorganic anion exchanger that integrates the advantages of both hydrotalcite-like structure and bismuth compound stability, achieving balanced performance in anion exchange, moisture resistance, and thermal stability

Inventive Principle:

Principle #40Composite materials

2Temperature

If flame retardants (antimony oxide, brominated epoxy resin) are added to epoxy resin to improve flame resistance, then flame retardancy is enhanced, but corrosion of aluminum interconnects is promoted

Engineering Contradiction:

Improveflame resistanceVSAvoidcorrosion of aluminum interconnects

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent removes harmful halogen-containing flame retardants (antimony oxide, brominated epoxy resin) from the encapsulation material composition and replaces them with the novel bismuth compound that provides flame resistance through different mechanisms (hydroxide decomposition) without generating corrosive gases that damage aluminum interconnects

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potential harm of using flame retardants into a benefit by selecting a flame retardant mechanism (bismuth hydroxide decomposition) that produces protective effects: the decomposition releases water vapor that forms a protective atmosphere preventing corrosion, while the bismuth compound simultaneously provides anion exchange capability to capture corrosive ions

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If higher integration of semiconductors is achieved by reducing aluminum interconnect width, then device integration is improved, but corrosion resistance deteriorates due to moisture and heat

Engineering Contradiction:

Improvesemiconductor integrationVSAvoidcorrosion resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The novel bismuth compound acts as an intermediary substance within the epoxy resin encapsulation material that mediates between the semiconductor device and the external environment: it captures harmful anions (Cl-, F-, OH-) through ion exchange, absorbs excess moisture, and provides thermal stability, thereby protecting the highly integrated semiconductor interconnects from corrosion while allowing continued miniaturization

Inventive Principle:

Principle #24Intermediary (Mediator)

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 novel bismuth compound enhances anion exchangeability and moisture resistance, suppressing anion release and improving the reliability of electronic and electrical components, suitable for encapsulation, coating, and insulation, while being environmentally friendly.

Implementation Method 1

The bismuth compound absorbs moisture from the environment through adsorption, enhancing anion exchangeability

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

A novel bismuth compound that is useful as an inorganic anion exchanger

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentUS8017661B2Inorganic anion exchanger composed of bismuth compound and resin composition for electronic component encapsulation using the same

Publication Date: 2011.09.13 TOAGOSEI CO LTD

AI summary

A bismuth compound, useful as an inorganic anion exchanger used for an encapsulating material for, e.g., semiconductors, has a peak intensity of 900 to 2000 cps at 2θ=27.9° to 28.1° and a peak intensity of 100 to 800 cps at 2θ=8.45° to 8.55° in a powder X-ray diffraction pattern, and is represented by the following formula (1):Bi(OH)x(NO3)y.nH2O (1)wherein x is a positive number not less than 2.5 and less than 3, y is a positive number not more than 0.5, x+y=3, and n is 0 or a positive number.