Power Semiconductor Device Sealing with Casing Protrusion
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Solution Overview
Problem
Existing power semiconductor devices face challenges in filling a narrow spaced portion between two insulating circuit boards with a sealing material without gaps, which can lead to operational issues such as discharge of power.
Innovation Solution
A power semiconductor device configuration where a casing surrounds a first and second insulating circuit board, with a semiconductor element sandwiched between them, and a sealing material is introduced through a hole in one of the circuit boards and controlled by a protrusion on the casing to ensure complete filling without gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a narrow spaced portion is formed between two insulating circuit boards to achieve higher density, then the current conduction capability is improved, but the sealing material cannot be introduced without gaps
Solution Approach 1:
A protrusion is formed on the inner wall surface of the casing before sealing to extend into the narrow spaced portion. This preliminary structural arrangement guides the sealing material flow and ensures complete filling of the narrow gap between insulating circuit boards, preventing gaps that would compromise reliability
Solution Approach 2:
The protrusion acts as an intermediary structure between the casing and the narrow spaced portion. It mediates the sealing material introduction process by providing a flow path and pressure distribution mechanism that enables complete filling of the difficult-to-reach narrow gap while maintaining the high-density configuration
2Reliability
If a protrusion is added to control sealing material flow, then the sealing completeness is improved, but the device complexity increases
Solution Approach 1:
The protrusion is integrated directly into the casing structure, merging the sealing control function with the existing protective housing. This combination approach adds the necessary sealing guidance capability without requiring separate components or complex assembly steps, thus limiting the increase in device complexity
Data Source
AI summary
A power semiconductor device includes a casing, a first insulating circuit board, a second insulating circuit board, and a sealing material. The first insulating circuit board is disposed to be surrounded by the casing. The second insulating circuit board is surrounded by the casing and spaced from the first insulating circuit board so as to sandwich a semiconductor element between the first insulating circuit board and the second insulating circuit board. The sealing material fills a region surrounded by the casing. The first or second insulating circuit board is provided with a hole extending from one main surface to the other main surface opposite to one main surface. From at least a portion of an inner wall surface of the casing a protrusion extending to a region overlapping the first or second insulating circuit board in a plan view extends toward the region surrounded by the casing.