Power Module Guide Groove Structure for Solder Overflow Control
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Solution Overview
Problem
The overflow and movement of solder during the bonding process of a semiconductor chip and spacer to a substrate in power modules can lead to electrical short circuits and exposure of insulating layers, compromising bonding quality and durability under high temperature conditions.
Innovation Solution
A power module design incorporating guide grooves on the substrates to guide molten solder in a horizontal direction, preventing vertical overflow and minimizing insulator exposure, thereby enhancing bonding quality and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is performed to bond chip and spacer to substrates, then electrical connection is achieved, but solder overflow occurs causing short circuits and insulator exposure
Solution Approach 1:
The substrate surface is segmented into multiple regions by forming guide grooves that divide the solder flow path. These grooves create separate zones that guide and contain the molten solder, preventing uncontrolled overflow while maintaining effective bonding areas. The segmentation approach transforms the continuous substrate surface into a structured pattern that controls solder distribution.
Solution Approach 2:
Guide grooves are introduced as intermediary structures between the chip/spacer components and the substrate. These grooves act as mediators that intercept and redirect the molten solder flow, preventing direct contact between excess solder and critical areas like insulators. The grooves serve as a buffer zone that manages solder overflow without compromising the bonding function.
2Manufacturing precision
If solder is allowed to flow freely during bonding, then complete coverage is achieved, but insulating layers are exposed and thermal stress concentrates
Solution Approach 1:
The guide grooves are pre-formed on the substrate surface before the soldering process. This preliminary action creates a predetermined path and boundary for the molten solder, ensuring that when soldering occurs, the solder is automatically guided along the grooves and contained within safe zones. The pre-existing groove structure proactively prevents insulator exposure before it can occur.
Solution Approach 2:
The guide grooves create local variations in the substrate surface properties, establishing distinct zones with different functions. Areas within the grooves are designed to accommodate and guide solder flow, while areas between grooves maintain their insulating properties. This local differentiation allows solder to be concentrated in specific regions without exposing vulnerable insulating layers elsewhere.
3Object-affected harmful factors
If guide grooves are formed around chip connection portions, then solder overflow is prevented, but substrate structure becomes more complex
Solution Approach 1:
Rather than adding complex three-dimensional structures or multiple layers to prevent solder overflow, the solution utilizes the two-dimensional surface of the substrate by etching grooves into it. This approach controls solder flow in the horizontal plane through the groove patterns, avoiding the need for vertical complexity such as multiple substrate layers or additional protective components.
Solution Approach 2:
The guide grooves replace the need for mechanical solder containment structures such as solder stops, barriers, or additional protective components. Instead of using separate mechanical elements to physically block solder, the grooves use the substrate's own geometry and surface tension effects to guide and contain the molten solder through capillary action and surface adhesion.
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 guide grooves effectively prevent solder overflow and short circuits, ensuring reliable bonding and improved thermal and electrical performance by reducing insulator exposure and stress concentration.
Implementation Method 1
a guide groove portion formed of a plurality of grooves which is recessively formed in the upper substrate and the lower substrate around a connection portion of the chip, the guide groove portion being configured to guide molten solder when the chip is bonded to the upper substrate and the lower substrate by a soldering process
Data Source
AI summary
Provided is a power module capable of preventing an overflow situation of solder and a movement of the solder when a chip and a spacer are bonded to each substrate by a soldering process, thereby being capable of increasing bonding quality between components through the soldering process.