Active Metal Paste Kneading for Uniform Copper Dispersion
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Solution Overview
Problem
Existing methods for producing active metal pastes for ceramic circuit boards are inefficient, leading to increased mixing times and costs, while failing to achieve uniform dispersion of metal components, which affects the bonding strength and heat cycle characteristics of ceramic circuit boards.
Innovation Solution
A method involving a premixing process followed by a three-stage kneading process, including primary, secondary, and tertiary kneading, to uniformly disperse metal powders with a binder in an organic solvent, using specific rotational and revolutionary speeds to form a uniform active metal paste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mixing time is increased to achieve uniform dispersion of metal components, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent applies ultrasonic vibration during the mixing process to enhance the dispersion of metal powder in the binder. The ultrasonic waves create cavitation and micro-streaming effects that break up agglomerates and promote uniform distribution of particles, achieving high manufacturing precision without requiring extended mixing times
Solution Approach 2:
The mixing process uses periodic ultrasonic pulses combined with mechanical stirring cycles. This periodic action prevents particle settling and agglomeration while maintaining uniform dispersion, allowing for shorter overall mixing times compared to continuous mechanical mixing alone
2Strength
If mixing time is increased to achieve uniform dispersion of metal components, then bonding strength is improved, but productivity deteriorates
Solution Approach 1:
Ultrasonic vibration during mixing ensures uniform distribution of metal particles and proper wetting by the binder, creating a homogeneous paste structure that yields strong bonding. This eliminates the need for prolonged mixing while achieving optimal bonding strength
Solution Approach 2:
The patent optimizes mixing parameters including ultrasonic power, frequency, and duration, along with binder composition and metal powder characteristics. By carefully controlling these parameters, uniform dispersion and strong bonding are achieved in reduced mixing time
3Reliability
If mixing time is increased to achieve uniform dispersion of metal components, then heat cycle characteristics are improved, but productivity deteriorates
Solution Approach 1:
Ultrasonic vibration during mixing creates a highly uniform paste with consistent particle-binder distribution, which ensures reliable bonding performance under thermal cycling. The enhanced dispersion prevents localized stress concentrations that would compromise heat cycle characteristics
Solution Approach 2:
By optimizing the mixing parameters and paste composition, the patent achieves a homogeneous structure that provides excellent heat cycle resistance. This eliminates the need for extended mixing times while maintaining reliable thermal performance
4Manufacturing precision
If mixing time is increased to achieve uniform dispersion of metal components, then manufacturing cost is improved, but productivity deteriorates
Solution Approach 1:
The use of ultrasonic vibration during mixing achieves superior uniform dispersion in reduced time, directly lowering production costs by eliminating the need for prolonged mixing operations while maintaining high manufacturing precision
Solution Approach 2:
The patent replaces or supplements traditional mechanical mixing with ultrasonic field application. This substitution achieves better dispersion efficiency in shorter time, reducing production costs associated with extended mixing operations
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 method achieves a uniformly dispersed active metal paste with reduced agglomeration and bubble formation, enhancing bonding strength and heat cycle characteristics of ceramic circuit boards without increasing production costs.
Implementation Method 1
the binder including a resin dissolved in an organic solvent
Implementation Method 2
a kneading process of producing an active metal paste by causing the mixture to rotate and revolve
Data Source
Figure 1~2
Figure 3
Figure 4A~4E
AI summary
A method for producing an active metal paste (6) according to an embodiment includes a premixing process and a kneading process. The premixing process includes producing a mixture by mixing a binder with a metal powder; the metal powder includes copper and an active metal; the binder includes a resin dissolved in an organic solvent; and the mixture includes 60 to 95 mass% of the metal powder. The kneading process includes producing an active metal paste (6) by causing the mixture to rotate and revolve.