Lead-Free Solder Alloy Composition for Thermal and Impact Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lead-free solder alloys face challenges in simultaneously achieving high temperature cycle performance and drop impact performance, as the increase in silver content improves temperature cycle performance but deteriorates drop impact performance, and vice versa, while also being affected by the formation of intermetallic compound layers which impact solder joint reliability.
Innovation Solution
A lead-free solder alloy comprising 0.8-1.2 wt% silver, 0.8-1.2 wt% copper, 0.01-1.0 wt% palladium, 0.001-0.1 wt% tellurium, and the balance of tin, manufactured using a high-frequency vacuum induction furnace, which improves mechanical strength, thermal strength, and drop impact performance by forming denser intermetallic compound layers that prevent crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If intermetallic compound layers form during reflow soldering, then solder joint reliability is affected, but crack propagation resistance is reduced
Solution Approach 1:
The invention optimizes the composition parameters (Ag: 0.5-3.0 wt%, Cu: 0.1-5.0 wt%, Pd: 0.01-1.0 wt%) to control the formation and morphology of intermetallic compound layers, creating a balanced structure that maintains solder joint reliability while improving crack propagation resistance through refined microstructure
Solution Approach 2:
The Sn-Ag-Cu-Pd composite alloy system creates a refined microstructure with controlled intermetallic compound distribution, where palladium plays a key role in refining the structure and creating a balanced intermetallic layer that provides both reliability and crack resistance
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 alloy achieves improved temperature cycle and drop impact performance by forming denser intermetallic compound layers that enhance mechanical and thermal strength, addressing the limitations of prior alloys and meeting the reliability demands for electronic devices and printed circuit boards.
Implementation Method 1
manufactured using a high-frequency vacuum induction furnace
Data Source
AI summary
Disclosed herein are a lead-free solder alloy and a manufacturing method thereof. More specifically, disclosed are: a lead-free solder alloy, which comprises 0.8-1.2 wt % silver (Ag), 0.8-1.2 wt % copper (Cu), 0.01-1.0 wt % palladium (Pd), 0.001-0.1 wt % tellurium (Te), and a balance of tin (Sn), and thus has a melting point similar to those of prior lead-free solder alloys, excellent wettability, very low segregation ratio, and excellent weldability with a welding base metal, such that it improves temperature cycle performance and drop impact resistance simultaneously, when it is applied to electronic devices and printed circuit boards; a manufacturing method of the above alloy; and electronic devices and printed circuit boards which include the same.