Zinc-Based Lead-Free Solder Composition for Reliable Electronics Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronics packaging technologies face challenges with lead-free and tin-free solder compositions that fail to provide desirable melting, mechanical, and wetting properties, particularly in forming reliable connections between chips and lead frames without causing internal cracking failures.
Innovation Solution
The development of zinc-based solder compositions incorporating zinc, aluminum, germanium, gallium, and magnesium, along with a copper/zinc intermetallic layer formed during the soldering process, which promotes uniform wetting and prevents cracking by consuming the copper layer, ensuring a thin and durable intermetallic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free and tin-free solder compositions are developed, then health and environmental safety is improved, but desirable melting, mechanical, and wetting properties are not achieved
Solution Approach 1:
The patent changes the compositional parameters of the solder alloy by using zinc as the base metal with specific proportions of aluminum (3-15 wt%), germanium (3-7 wt%), gallium (0.25-0.50 wt%), and magnesium (0.125-0.35 wt%). This parameter optimization enables the solder to achieve desirable melting properties (liquidus temperature of 360-380°C), mechanical properties (elongation greater than 5%), and wetting properties without containing lead or tin
Solution Approach 2:
The patent creates a composite solder material system where zinc serves as the base metal combined with multiple alloying elements (aluminum, germanium, gallium, magnesium). This composite composition synergistically provides both the required health and environmental safety (lead-free, tin-free) and the necessary functional properties for reliable soldering connections
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 zinc-based solder compositions exhibit improved melting, mechanical, and wetting properties, reducing the likelihood of cracking failures and enhancing the endurance of electronics packaging arrangements by forming a thin, durable copper/zinc intermetallic layer during the soldering process.
Implementation Method 1
a copper/zinc intermetallic layer is formed during the flow and solidification of the solder
Implementation Method 2
a relatively thin wetting promoting layer to promote uniform wetting of a solder, such as a lead-free and tin-free, zinc-based solder, onto the lead frame
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
Electronic packaging arrangements having lead-free solders are disclosed. In particular, lead-free solder compositions and lead frame constructs for use therewith are disclosed. The lead-free solder compositions may be zinc-based and may include zinc, aluminum, and germanium as major components and gallium and magnesium as minor components. The lead-free, zinc-based solder compositions may exhibit desirable melting properties, mechanical properties, and wetting properties, for example.