Electronic Module Side Groove Fillet for Thermal Stress Relief
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Solution Overview
Problem
The reduction in size and increased density of electronic components lead to challenges in the reliability of connection between mounting electrodes on the side surface of insulating substrates and connecting circuit portions on circuit boards, particularly under thermal stress.
Innovation Solution
An electronic module design where the mounting electrodes are disposed within grooves on the side surface of the insulating substrate, with a fillet of joining material extending from the electrode to the circuit board, reducing thermal stress and enhancing the reliability of the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the mounting electrodes are reduced in size to decrease the wiring board size and increase density, then the board size is reduced and density is increased, but the reliability of connection between the mounting electrodes and connecting circuit portions deteriorates under thermal stress
Solution Approach 1:
The mounting electrodes are disposed on the side surface of the insulating substrate rather than the principal surface, transitioning from a planar arrangement to a three-dimensional configuration. This allows the electrodes to extend vertically along the side surface, increasing their effective connection area without increasing the horizontal footprint of the wiring board, thus maintaining size reduction while improving connection reliability
Solution Approach 2:
Grooves are formed on the side surface of the insulating substrate to accommodate the mounting electrodes, creating a curved or recessed structure. This groove configuration increases the surface area available for electrode placement and provides a mechanical interlock structure that enhances connection reliability under thermal stress while maintaining compact dimensions
2Volume of moving object
If the mounting electrodes are disposed on the side surface of the insulating substrate, then the wiring board size is reduced, but the connection reliability under thermal stress deteriorates due to the small surface area available
Solution Approach 1:
The mounting electrodes utilize the vertical dimension of the side surface rather than only the horizontal plane, extending the electrode structure along the thickness direction of the insulating substrate. This three-dimensional arrangement increases the effective connection area without increasing the wiring board's horizontal dimensions
Solution Approach 2:
Grooves are formed on the side surface to create a recessed structure that accommodates the mounting electrodes. This curved or recessed geometry increases the available surface area for electrode placement and provides mechanical interlocking, thereby improving connection reliability while maintaining compact board size
Data Source
AI summary
In an electronic module 30, a groove 3 is disposed in a single side surface A of an electronic device 20 that faces an outer principal surface 33 of a circuit board 31. In the groove 3, an end portion of a mounting electrode 2 near a joining body 21 is located further toward an insulating substrate 1 than an end portion 3 of the groove 3 near the joining body 21. A fillet F of a joining material 41 is disposed in a region of the groove 3 near the joining body 21. Owing to the fillet F, the reliability of connection between the electronic device 20 and the circuit board 31 can be increased.