Lead-Free Solder Alloy Electro-Migration Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lead-free solder alloys fail to sufficiently suppress electro-migration in solder joint portions, particularly in miniaturized components, leading to void formation and disconnection due to high current density.
Innovation Solution
A lead-free solder alloy comprising Sb in the range of 3.0% to 10% by mass, with Sn as the main component, and optionally including Ag, Cu, Ni, Co, and Ge, which maintains appropriate melting temperatures and flowability while effectively reducing electro-migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lead-free solder alloys are used, then the solder joint can be formed, but electro-migration occurs leading to void formation and disconnection in miniaturized components
Solution Approach 1:
The invention changes the compositional parameters of the solder alloy by specifying precise ranges for Sn (90-99.5 mass%), Sb (0.5-10 mass%), and Cu (0-5 mass%). This parameter optimization resolves the contradiction by achieving electro-migration suppression while maintaining solder joint integrity, directly addressing the void formation and disconnection problems in miniaturized components
2Volume of moving object
If the solder joint portion is miniaturized, then component size is reduced, but electro-migration increases causing reliability issues
Solution Approach 1:
The invention optimizes the compositional parameters of the solder alloy with specific ranges for Sn, Sb, and Cu to address electro-migration in miniaturized solder joints. The controlled composition maintains appropriate melting characteristics and flowability while providing electro-migration suppression, enabling reliable connections in fine solder joints without requiring changes to the miniaturization trend
3Reliability
If Ag or Cu is added to suppress electro-migration, then electro-migration resistance improves, but melting temperature control becomes difficult
Solution Approach 1:
The invention carefully controls the compositional parameters with Sn at 90-99.5 mass%, Sb at 0.5-10 mass%, and Cu at 0-5 mass% to achieve both electro-migration suppression and appropriate melting temperature. This balanced composition resolves the contradiction by preventing excessive melting temperature while maintaining electro-migration resistance
Solution Approach 2:
The invention creates a composite solder alloy system combining Sn, Sb, and Cu in optimized proportions. This composite material approach resolves the contradiction by leveraging the complementary properties of each element: Sn provides base solder characteristics, Sb enhances electro-migration resistance, and Cu improves strength while controlling melting behavior
Data Source
AI summary
Provided are a lead-free solder alloy which consists of Sb in an amount of more than 3.0% but 10% or less by mass, and the balance including Sn, and others.