Flake-Shaped Silver Oxide Paste for Low-Temperature Die Bonding
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Solution Overview
Problem
Conventional silver oxide particles with a spherical shape exhibit insufficient bonding strength at low temperatures, leading to issues such as cracking and peeling in power semiconductor devices.
Innovation Solution
The use of nano-sized, flake-shaped silver oxide particles with specific thickness and D50 values, along with a dispersant and dispersion medium, facilitates bonding at low temperatures without cracking or peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If spherical silver oxide particles are used for bonding, then the bonding temperature can be kept low, but the bonding strength is insufficient and cracking/peeling occurs
Solution Approach 1:
The invention changes the shape parameter of silver oxide particles from spherical to flake-shaped, and controls the thickness parameter to be 1 to 100 nm. This parameter change enables the particles to provide sufficient bonding strength at low bonding temperatures (below 250°C) while preventing cracking and peeling, thus resolving the contradiction between low bonding temperature and sufficient bonding strength.
Solution Approach 2:
The invention creates a composite bonding material consisting of flake-shaped silver oxide particles combined with organic vehicle components. This composite structure leverages the unique properties of flake-shaped nanoparticles to achieve both low bonding temperature and high bonding strength, overcoming the limitations of conventional spherical particles.
2Reliability
If conventional bonding materials (solder alloys, epoxy-based conductive adhesives) are used, then bonding can be achieved, but they cannot withstand operating temperatures of 200°C or more
Solution Approach 1:
The invention uses silver oxide particles with controlled thickness (1 to 100 nm) and flake shape, which undergo reduction to metallic silver at low temperatures. This phase change parameter enables the bonding material to withstand operating temperatures of 200°C or more while maintaining reliability, unlike conventional bonding materials that degrade at such temperatures.
3Strength
If flake-shaped silver oxide particles with nano-sized thickness are used, then good bonding strength is achieved at low temperatures, but particle production and dispersion become more challenging
Solution Approach 1:
The invention uses organic vehicles (dispersants and dispersion media) as intermediaries to facilitate the dispersion and processing of flake-shaped silver oxide particles. The dispersant adsorbs onto the particle surfaces preventing aggregation, while the dispersion medium provides a suitable vehicle for application, thereby easing the manufacturing challenges of handling nano-sized flake particles.
Solution Approach 2:
The invention optimizes the thickness parameter of flake-shaped particles to 1 to 100 nm and controls the size distribution (D50 of 100 to 350 nm). These parameter optimizations balance the bonding performance with manufacturability, making the particles easier to produce and disperse while maintaining excellent low-temperature bonding strength.
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 flake-shaped silver oxide particles provide good bonding strength even at temperatures below 250°C, enhancing the reliability of semiconductor devices.
Implementation Method 1
silver oxide particles having an average thickness of 1 to 100 nm... bonding at low temperatures... reducing the thermal load on the semiconductor element
Data Source
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AI summary
The present invention provides a bonding material that achieves good bonding strength even when bonding at low temperatures. Flake-shaped silver oxide particles or a silver oxide powder containing the particles are provided. The flake-shaped silver oxide particles have an average thickness of 10 to 100 nm and a D50 of 100 to 350 nm. Moreover, the flake-shaped silver oxide particles or silver oxide powder containing the particles may be used as a paste for bonding a semiconductor substrate with, for example, a power semiconductor chip.