Semiconductor Module Base Plate Recess for Insulation and Compactness
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Solution Overview
Problem
Conventional semiconductor units face a challenge in achieving both insulation properties between the screw for attaching a cooler and a horizontal terminal of a semiconductor module and downsizing, as these requirements are often contradictory.
Innovation Solution
The semiconductor unit design includes a base plate with screw holes that have a spot facing part with a smaller depth than the base plate thickness, allowing screws to be housed within this part, ensuring insulation properties while enabling downsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base plate is made larger to ensure insulation distance between the screw and horizontal terminal, then insulation properties are improved, but the overall size of the semiconductor unit increases
Solution Approach 1:
The invention transitions from ensuring insulation through horizontal distance (2D plane) to ensuring insulation through vertical depth (3D space). By creating a spot facing part that extends downward into the base plate, the insulation distance is measured vertically from the terminal surface to the screw head, rather than horizontally across the base plate surface. This dimensional change allows compact horizontal spacing while maintaining adequate insulation clearance.
Solution Approach 2:
The screw head is nested within the spot facing part of the base plate. The spot facing part creates a recess that houses the screw head, positioning it below the terminal surface level. This nesting arrangement ensures that the screw does not protrude beyond the base plate surface, thereby maintaining insulation distance without requiring additional horizontal space.
2Volume of stationary object
If the screw is positioned closer to the terminal to reduce unit size, then downsizing is achieved, but insulation properties deteriorate
Solution Approach 1:
The invention resolves this contradiction by measuring insulation distance in the vertical dimension rather than the horizontal dimension. The spot facing part depth creates a vertical clearance between the terminal surface and the screw head, allowing the screw to be positioned closer horizontally to the terminal while maintaining adequate insulation distance through the vertical depth of the spot facing part.
3Reliability
If a deep spot facing part is provided to house the screw completely, then insulation properties are improved, but manufacturing complexity and base plate thickness increase
Solution Approach 1:
The invention optimizes the depth parameter of the spot facing part to balance insulation performance with manufacturing simplicity. Rather than creating an excessively deep recess, the spot facing part depth is set to a practical value that provides sufficient insulation clearance while remaining manufacturable using conventional machining processes. This parameter optimization avoids excessive base plate thickness and manufacturing complexity.
Solution Approach 2:
The spot facing part is provided only at specific locations where screws are required, rather than throughout the entire base plate. This localized approach creates the necessary insulation structure only where needed, maintaining simple construction in other areas of the base plate and avoiding unnecessary increases in overall base plate thickness and manufacturing complexity.
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
This design achieves both effective insulation between the screw and horizontal terminal and reduces the overall size of the semiconductor unit, enhancing its structural integrity and cooling efficiency.
Implementation Method 1
a cooler (2) attached to the lower surface of the base plate (3) and cooling the semiconductor module (1)
Implementation Method 2
a cooler (2) attached to the lower surface of the base plate (3) and cooling the semiconductor module (1)
Data Source
AI summary
A semiconductor unit includes: a semiconductor module including a semiconductor device and a horizontal terminal; a base plate including an upper surface to which the semiconductor module is bonded and a plurality of screw holes passing through the base plate from the upper surface to a lower surface; a cooler attached to the lower surface of the base plate and cooling the semiconductor module; and a plurality of screws screwed to the plurality of screw holes of the base plate, respectively, so that the cooler is attached to the lower surface of the base plate. A spot facing part having a depth smaller than a thickness of the base plate is provided to a part of at least one of the plurality of screw holes on a side of the upper surface of the base plate.