Semiconductor Bonding Substrate With Edge Concaves for Solder Voids
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Solution Overview
Problem
Solder shrinkage cavities occur during the bonding of semiconductor elements to substrates, leading to reduced heat radiation properties and electrical characteristics, particularly in high-temperature and high-current-density applications like SiC and GaN semiconductors, necessitating a solution to suppress cavity formation and improve heat radiation.
Innovation Solution
A semiconductor element bonding substrate with a metal pattern featuring concave or grooved regions near the edge of the bonding area, where the solder is supplied and clots first, and varying heights or conductivities to control solder shrinkage, thereby reducing cavity formation and enhancing heat radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar metal pattern is used for solder-bonding the semiconductor element, then the bonding process is simple and easy to manufacture, but a shrinkage cavity easily occurs in the solder, reducing heat radiation property and electrical characteristics
Solution Approach 1:
The metal pattern is designed with a concave portion at a specific location (closer to the edge than the center of the bonding region) to create local structural variation. This local quality change allows the solder to fill the concave area first during bonding, controlling the solidification sequence and preventing shrinkage cavities from forming under the semiconductor element, thus improving heat radiation property while maintaining manufacturing simplicity
2Device complexity
If a planar metal pattern is used for solder-bonding the semiconductor element, then the device structure is simple, but a shrinkage cavity occurs immediately below the semiconductor element, reducing productivity due to rework or discarding
Solution Approach 1:
The concave portion is pre-formed in the metal pattern at the optimal location before the soldering process. This preliminary structural preparation ensures that when solder is applied, it naturally fills the concave area first and solidifies in a controlled sequence, preventing shrinkage cavity formation before the semiconductor element is fully bonded. This eliminates the need for rework or discarding defective devices, thereby improving productivity
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 proposed substrate design effectively suppresses solder shrinkage cavities, improving heat radiation properties and maintaining stable semiconductor device operation by ensuring uniform solder distribution and reducing thermal resistance.
Implementation Method 1
When the melted solder is clotted, the solder filling the inner side of the concave part shrinks
Implementation Method 2
The at least one concave part is located closer to an edge of the bonding region in relation to a center part of the bonding region
Data Source
AI summary
A semiconductor element bonding substrate according to the present invention includes an insulating plate, and a metal pattern bonded to a main surface of the insulating plate. A main surface of the metal pattern on an opposite side of the insulating plate includes a bonding region to which a semiconductor element is bonded by a solder. The metal pattern includes at least one concave part located in the main surface. The at least one concave part is located closer to an edge of the bonding region in relation to a center part of the bonding region in the bonding region.