Lead-Free Solder Composition Using Flower-Shaped Nanoparticles
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Solution Overview
Problem
Existing lead-free solder alloy compositions with spherical metal nano-particles suffer from agglomeration issues, leading to reduced mechanical properties and misalignment during soldering processes due to high adhesion forces, which affects the performance and reliability of semiconductor devices.
Innovation Solution
Incorporating flower-shaped metal nano-particles with protrusion portions extending from a metal core, made of a single metal element, into the lead-free solder alloy composition to reduce adhesion forces and enhance dispersion, thereby improving mechanical properties and preventing misalignment during soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spherical metal nano-particles are used in lead-free solder alloy composition, then the composition can be manufactured with conventional methods, but the nano-particles suffer from agglomeration due to high adhesion forces, leading to reduced mechanical properties and misalignment during soldering
Solution Approach 1:
The patent applies asymmetry by changing the shape of metal nano-particles from spherical to flower-shaped with protrusion portions. This asymmetric geometry reduces adhesion forces between particles, preventing agglomeration while maintaining ease of manufacture. The flower-shaped particles with their extended protrusions have lower surface contact area, directly resolving the contradiction between manufacturability and reliability.
2Device complexity
If spherical metal nano-particles are used, then the manufacturing process remains simple, but the high adhesion forces cause agglomeration and misalignment during soldering processes
Solution Approach 1:
The flower-shaped metal nano-particles with protrusion portions create asymmetric structures that reduce inter-particle adhesion. This shape modification prevents agglomeration and improves alignment precision during soldering without significantly complicating the manufacturing process, as the flower-shaped particles can be produced using conventional nanoparticle synthesis methods.
Solution Approach 2:
The patent changes the geometric parameters of metal nano-particles by introducing protrusion portions extending from the core surface. This parameter change in particle morphology (from spherical to flower-shaped) reduces adhesion forces and improves alignment precision while maintaining manufacturing simplicity.
3Ease of manufacture
If conventional spherical metal nano-particles are used, then the solder alloy composition can be easily manufactured, but the mechanical properties such as flexural modulus, shear modulus, and toughness are reduced due to agglomeration
Solution Approach 1:
The flower-shaped metal nano-particles with protrusion portions create asymmetric structures that minimize contact area between particles, reducing adhesion forces and preventing agglomeration. This maintains uniform dispersion in the solder alloy, thereby preserving and enhancing mechanical properties such as flexural modulus, shear modulus, and toughness while keeping the manufacturing process simple.
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 use of flower-shaped metal nano-particles in the lead-free solder alloy composition improves mechanical properties such as flexural modulus, strain, shear modulus, ultimate tensile strength, rigidity, and toughness, while preventing misalignment between solder paste and solder ball, thus enhancing the reliability of hybrid bonding structures in semiconductor devices.
Implementation Method 1
mixing the lead-free solder alloy with the metal nano-particle by performing an ultrasonic processing
Implementation Method 2
removing the hexane solution by performing a thermal treatment
Data Source
AI summary
A lead-free solder alloy composition includes a lead-free solder alloy; and a flower-shaped metal nano-particle including a metal core and protrusion portions extending from a surface of the metal core, wherein the metal core and the protrusion portions of the metal nano-particle include only one metal element.