Grooved Current Detection Resistor for Compact IGBT Integration
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Solution Overview
Problem
Conventional power modules require a large mounting area for shunt resistors due to their vertical structure, which is challenging to integrate with complex semiconductor devices like IGBTs, especially with insulating films partitioning the electrodes, making it difficult to reduce the footprint.
Innovation Solution
A current detection resistor with a plate-like resistive body and stacked electrodes, where the first electrode has a groove portion, allowing for vertical integration and reducing the mounting area by eliminating the need for bonding wires and minimizing the adhesive volume, with surface processing films for improved adhesion and connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shunt resistor is mounted adjacent to the IGBT device on the substrate, then the current detection function is achieved, but the mounting area increases
Solution Approach 1:
The shunt resistor is integrated directly onto the upper surface of the IGBT device, merging two previously separate components (IGBT and shunt resistor) into a single composite structure. This eliminates the need for separate mounting space on the substrate, thereby reducing the overall mounting area while maintaining current detection functionality.
Solution Approach 2:
The shunt resistor is positioned in the vertical dimension (on the upper surface) rather than the horizontal plane (adjacent on substrate). This three-dimensional integration approach allows the shunt resistor to occupy space above the IGBT device, effectively utilizing the vertical dimension to reduce the horizontal footprint of the module.
2Area of stationary object
If a vertical shunt resistor structure is provided on the upper surface of the power semiconductor, then the mounting area is reduced, but the complex electrode structure with insulating films makes integration difficult
Solution Approach 1:
The upper surface electrodes of the IGBT device are segmented into multiple divided portions (comb-shaped electrodes) by insulating films. The shunt resistor is designed to bridge across these segmented electrodes, with its electrode structure divided into multiple regions that correspond to the segmented IGBT electrodes. This segmentation allows the shunt resistor to be integrated despite the complex electrode structure.
Solution Approach 2:
The shunt resistor electrode structure is designed with different local configurations: some regions contact the IGBT emitter electrodes directly, while other regions are separated by insulating films. This local differentiation in electrode structure allows the shunt resistor to adapt to the complex IGBT electrode arrangement while maintaining electrical connectivity where needed and electrical isolation where required.
3Reliability
If bonding wires are used to connect emitter electrodes and shunt resistor electrodes, then electrical connectivity is achieved, but the mounting area and device complexity increase
Solution Approach 1:
The shunt resistor electrode structure is designed to directly contact and integrate with the IGBT emitter electrodes, merging the electrical connection function into the resistor structure itself. This eliminates the need for separate bonding wires, as the resistor electrodes serve as both the detection elements and the electrical connection points.
Solution Approach 2:
The bonding wire connection function is extracted and eliminated by designing the shunt resistor with integrated electrode contacts that directly interface with the IGBT electrodes. This removes the bonding wires from the system, simplifying the structure and reducing the mounting area.
4Area of stationary object
If the IGBT device and shunt resistor are integrated vertically, then the mounting area is reduced, but adhesive volume must be secured and excess solder attachment must be prevented
Solution Approach 1:
Groove portions are pre-formed in the shunt resistor electrode structure at locations where adhesive will be applied. These grooves are designed with specific dimensions and positions that preliminary define the adhesive application area, ensuring that the adhesive is contained within precise boundaries during the bonding process, thereby controlling adhesive volume and preventing excess solder attachment.
Solution Approach 2:
The groove portions in the electrode structure serve as intermediary containment features that mediate between the adhesive and the bonding surfaces. These grooves act as physical barriers that guide and limit adhesive flow, ensuring proper adhesive distribution and preventing adhesive or solder from spreading to unwanted areas during the bonding process.
Data Source
AI summary
The mounting area for an electronic component and a resistor for current detection is reduced. A current detection resistor for detecting current includes a plate-like resistive body, and a first electrode and an opposite second electrode which are stacked in a thickness direction of the resistive body and are disposed so as to sandwich the resistive body. The first electrode has a groove portion.