Semiconductor Device Creepage Distance via Hollow Portion
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Solution Overview
Problem
Conventional semiconductor devices face challenges in increasing breakdown voltage due to limitations in creepage distance and clearance between external terminals and metallic components.
Innovation Solution
The semiconductor device design incorporates a case portion with a protruding wall and a depressed hollow portion on its front surface, allowing for increased creepage distance and clearance by positioning external terminals within the hollow portion, which can be deeper than the wall, and featuring irregularities on the side surface to enhance electrical insulation and voltage handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the creepage distance and clearance between external terminal and metallic portion are increased to raise breakdown voltage, then the breakdown voltage is improved, but the device size increases
Solution Approach 1:
The patent utilizes the depth dimension by forming a hollow portion that extends downward from the front surface of the case portion. The external terminal is positioned within this hollow portion, allowing the creepage distance to extend in the depth direction rather than only in the planar area. This dimensional transition enables increased breakdown voltage without proportionally increasing the device footprint area.
Solution Approach 2:
The external terminal is nested within the hollow portion of the case portion, creating a layered structure where the terminal is positioned inside a recessed space. This nesting arrangement allows the terminal to be surrounded by insulating material in multiple directions, effectively increasing the creepage distance and clearance without requiring additional lateral space, thus resolving the contradiction between reliability improvement and device size control.
2Reliability
If the hollow portion depth is increased to further increase creepage distance, then the breakdown voltage is improved, but the manufacturing complexity increases
Solution Approach 1:
The hollow portion is designed with specific dimensional relationships where its depth is controlled relative to the wall portion height. The patent specifies that the hollow portion depth should be at least twice the wall portion height, creating a segmented structure that can be molded in stages or with controlled cavity pressure. This segmentation approach allows for increased creepage distance while managing manufacturing complexity through structured design parameters.
Solution Approach 2:
The patent establishes specific parameter relationships to balance breakdown voltage improvement with manufacturing feasibility. The hollow portion depth is set as a multiple (at least twice) of the wall portion height, creating a scalable parameter system. This parameter-based design allows manufacturers to adjust dimensions while maintaining the functional relationship, making it easier to control molding processes even as the hollow portion depth increases for higher breakdown voltage requirements.
Data Source
AI summary
For a purpose of raising the breakdown voltage of a semiconductor device, the creepage distance and clearance between an electrode terminal and another metallic portion are preferably increased. A semiconductor device is provided, the semiconductor device including: a semiconductor element; a case portion that houses the semiconductor element; and an external terminal provided to a front surface of the case portion, wherein the front surface of the case portion has, formed thereon: a wall portion that protrudes from the front surface; and a hollow portion that is provided to a region surrounded by the wall portion and is depressed relative to the front surface, and the external terminal is arranged on a floor surface of the hollow portion.