Nanoparticle Sintered Bonding for Low-Temperature Semiconductor Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing mounting structures for high-temperature semiconductor elements, such as SiC and GaN, face challenges with thermal damage and prolonged bonding times when using nanoparticle sintering materials, as they require high temperatures and long processing times, which increase costs and reduce product quality.
Innovation Solution
A mounting structure utilizing a sintered body composed of a first metal and a second metal, where the second metal has a higher diffusion coefficient than the first metal, with a content ratio below the solid solution limit, to facilitate bonding at lower temperatures and reduce thermal damage, using nanoparticles with diameters of 100 nm or less to enhance sintering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If solder material is used for bonding element electrode and lead frame electrode, then bonding at low temperature is possible, but heat resistance cannot be ensured at 200°C to 250°C
Solution Approach 1:
The patent changes the material parameters by using high melting point metal particles (Ag, Cu, Al) instead of traditional solder material, enabling bonding at temperatures below 100°C while maintaining heat resistance up to 250°C. This parameter change resolves the contradiction between low bonding temperature and high heat resistance.
Solution Approach 2:
The patent creates a composite bonding structure using metal particles combined with organic binder materials. This composite approach allows the bonding to occur at low temperatures while the metal particles provide the necessary heat resistance, resolving the contradiction between bonding temperature and heat resistance.
2Reliability
If high melting point metal such as Ag and Cu is used for bonding, then heat resistance is excellent, but bonding requires heating to 1000°C to 1200°C which is impractical
Solution Approach 1:
The patent changes the particle size parameter to nanoscale dimensions (1-100 nm), which dramatically reduces the sintering temperature from 1000-1200°C to below 100°C. This parameter change maintains the heat resistance of high melting point metals while making the bonding process practical.
Solution Approach 2:
The patent utilizes the phase transition properties of nanoscale metal particles, where quantum effects and surface energy at the nanoscale enable sintering at temperatures far below the melting point, resolving the contradiction between maintaining heat resistance and reducing bonding temperature.
3Temperature
If nanoparticle mounting material is used for bonding, then bonding temperature can be reduced, but bonding time increases to 30 min to 60 min or longer
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: particle size (1-100 nm), particle shape (spherical, irregular), and organic binder composition. These parameter optimizations enable bonding completion in 5-30 minutes at temperatures below 100°C, resolving the contradiction between low bonding temperature and reduced bonding time.
Solution Approach 2:
The patent introduces organic binder materials as intermediaries that facilitate the bonding process at low temperatures. These binders enable rapid bonding by providing a matrix that holds particles together during sintering, reducing the required bonding time while maintaining low temperatures.
4Productivity
If sintering temperature is increased to shorten bonding time, then bonding speed increases, but thermal damage occurs to peripheral members
Solution Approach 1:
The patent changes the particle size parameter to nanoscale dimensions, which enables rapid bonding (5-30 minutes) at temperatures below 100°C. This parameter change achieves high productivity while avoiding thermal damage to peripheral members that would occur at higher temperatures.
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
This approach allows for faster bonding without thermal damage, maintaining the physical properties of the metal and preventing intermetallic compound formation, thus improving the efficiency and cost-effectiveness of the mounting process.
Implementation Method 1
the second metal is a metal having a diffusion coefficient in the first metal larger than a self-diffusion coefficient of the first metal
Implementation Method 2
bonding at a low temperature is possible for the solder material... use of particles of the high melting point metal having an average particle diameter of several nm to several hundred nm as a nanoparticle mounting material
Data Source
AI summary
A mounting structure is used, which includes: a semiconductor element including an element electrode; a metal member; and a sintered body configured to bond the semiconductor element and the metal member is used, in which the sintered body contains a first metal and a second metal solid-dissolved in the first metal, the second metal is a metal having a diffusion coefficient in the first metal larger than a self-diffusion coefficient of the first metal, and a content ratio of the second metal relative to a total mass of the first metal and the second metal in the sintered body is equal to or lower than a solid solution limit of the second metal to the first metal.