Core-Shell Solder Particles for Low-Temperature Semiconductor Bonding
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Solution Overview
Problem
Existing solder materials with high melting points cause thermal stress and defects in highly integrated semiconductor packages due to thermal expansion coefficient mismatches, necessitating a low-temperature mounting solution that maintains mechanical integrity.
Innovation Solution
A metal particle for adhesive paste with a core-shell structure, where the core has a higher melting point than the shell, and nanoparticles are uniformly distributed in the shell to prevent coagulation and enhance mechanical properties, allowing low-temperature bonding without degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high melting point solder materials are used, then bonding strength is improved, but thermal stress and defects increase due to thermal expansion coefficient mismatches
Solution Approach 1:
The solder particle is divided into a core and a shell. The core (high melting point metal) provides bonding strength, while the shell (low melting point metal) reduces thermal stress. This segmentation allows each component to fulfill its specific function, resolving the contradiction between strength and thermal stress.
Solution Approach 2:
The invention uses a composite structure combining high melting point metal (core) and low melting point metal (shell). This composite material approach allows the solder particle to exhibit both high bonding strength (from the core) and low thermal stress (from the shell), directly resolving the technical contradiction.
2Object-affected harmful factors
If low melting point materials are used for mounting, then thermal stress is reduced, but mechanical integrity and bonding strength deteriorate
Solution Approach 1:
The solder particle is segmented into core and shell, where the shell (low melting point) reduces thermal stress during mounting, while the core (high melting point) maintains mechanical integrity. This segmentation resolves the contradiction by assigning different functions to different parts.
Solution Approach 2:
The composite structure of high melting point core and low melting point shell allows the material to exhibit both low thermal stress (from the shell) and high mechanical integrity (from the core), resolving the contradiction between these two properties.
3Strength
If nanoparticles are added to enhance mechanical properties, then bonding strength is improved, but nanoparticle coagulation occurs reducing uniformity
Solution Approach 1:
The shell metal matrix acts as an intermediary that uniformly distributes and stabilizes nanoparticles. The shell prevents nanoparticle coagulation by providing a protective matrix, while still allowing the nanoparticles to enhance mechanical properties. This resolves the contradiction between strength enhancement and composition stability.
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 core-shell structure with nanoparticles improves mechanical properties and reduces thermal stress, minimizing defects in semiconductor packages by uniformly distributing nanoparticles in the shell metal matrix, enhancing bonding strength and toughness.
Implementation Method 1
the shell may include a metal having a lower melting point than the core
Implementation Method 2
nanoparticles uniformly distributed in the shell metal matrix
Implementation Method 3
a large number of semiconductor devices are mounted on a single board with a high level of integration. Here, a material enabling mounting at a low temperature of 200° C. or less is needed in order to reduce defects and performance degradation in semiconductor packages or modules caused by thermal damage
Data Source
AI summary
Provided is a metal particle for adhesive paste. The metal particle may include a core including at least one metal; and a shell on at least one surface of the core and including at least one metal and nanoparticles. The metal particle may be a transient liquid phase particle and the at least one metal of the core may have a higher melting point than a melting point of the at least one metal of the shell. In addition, provided are a method of preparing the metal particle for adhesive paste, a composite bonding structure formed from the metal particle for adhesive paste, and a semiconductor device including the composite bonding structure.