Power Semiconductor Device Metallized Layer Thickness Ratio
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Solution Overview
Problem
The use of sinterable metal bonding materials in power semiconductor devices leads to weakened holding forces due to warping of semiconductor elements during thermal processes, resulting in reduced contact area and increased risk of displacement, which compromises the reliability and yield of the power module.
Innovation Solution
The thickness ratio of the rear-surface metallized layer to the front-surface metallized layer is adjusted between 0.5 to 2.0 to minimize warping and enhance the contact area, ensuring stable temporary fixation and bonding, thereby improving the reliability and yield of the power semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If sinterable metal bonding material is used for bonding semiconductor element to substrate, then heat resistance performance is improved, but holding force is weakened due to warping during thermal processes
Solution Approach 1:
The invention changes the physical-chemical parameters of the metallized layers by controlling their thickness ratio. By setting the thickness of the rear-surface metallized layer to 0.5-2.0 times the thickness of the front-surface metallized layer, the thermal stress distribution is optimized, reducing warping while maintaining bonding strength at high temperatures.
Solution Approach 2:
The invention applies different thickness ratios of metallized layers at different locations (front surface vs. rear surface) of the semiconductor element. This local differentiation allows the rear surface to have enhanced warping resistance through thicker metallization, while the front surface maintains its original design characteristics.
2Loss of energy
If sinterable metal bonding material is used, then heat dissipation property is improved, but contact area is reduced due to warping, leading to displacement
Solution Approach 1:
By adjusting the thickness parameter of the metallized layers, the invention controls the warping behavior of the semiconductor element during thermal processes. This ensures that the element maintains flat contact with the bonding material, preserving both heat dissipation efficiency and positioning accuracy.
3Loss of energy
If bonding layer is made thinner to improve heat dissipation, then heat dissipation property is improved, but reliability is reduced due to void generation
Solution Approach 1:
The invention enhances the local quality of the bonding interface by increasing the metallized layer thickness at the rear surface. This provides a larger bonding area and better mechanical interlocking, allowing the use of thinner bonding layers without compromising reliability, thus maintaining both heat dissipation and bonding strength.
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 thickness ratio adjustment effectively reduces warping and displacement of semiconductor elements, ensuring a higher yield and reliability of the power module by maintaining a stable bonding interface under thermal stress.
Implementation Method 1
a sinterable metal bonding material utilizing a sintering phenomenon of metal fine particles
Implementation Method 2
After bonding, diffusion bonding occurs between the metal fine particles, and diffusion bonding occurs also between a metalized layer of a semiconductor element and a surface of a substrate
Data Source
AI summary
This power semiconductor device is provided with: a substrate; and a semiconductor element which is bonded onto the substrate using a sinterable metal bonding material. The semiconductor element comprises: a base; a first conductive layer that is provided on a first surface of the base, said first surface being on the substrate side; and a second conductive layer that is provided on a second surface of the base, said second surface being on the reverse side of the first surface. The thickness of the first conductive layer is from 0.5 times to 2.0 times (inclusive) the thickness of the second conductive layer.