Semiconductor Stack Pressure Distribution via Counter-Bored Insulating Plates
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Solution Overview
Problem
Pressure contact type semiconductor devices experience uneven pressure distribution due to the presence of a notch portion and varying distances from collector and emitter post surfaces, leading to decreased pressure application and increased risk of thermal destruction at the outer circumferential surface.
Innovation Solution
A pressure contact type semiconductor device stack with pressurizing means that includes metal fittings for insulating plates, conical or spherical pressurizing bodies, and spacers to ensure equal distances from pressurizing surfaces to chip surfaces, uniformly distributing pressure and preventing thermal destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the central portion of a press pack semiconductor device is pressurized with a spherical pressurizing surface, then unbalanced load is prevented, but the pressurized pressure decreases from the central portion toward the outer circumferential surface, making it difficult to uniformly pressurize the device and causing thermal destruction at the outer circumferential surface
Solution Approach 1:
The patent applies a spherical pressurizing surface to the pressurizing body to prevent unbalanced load. The spherical curvature allows the pressurizing body to self-align and distribute load evenly across the semiconductor device, preventing tilting and ensuring stable contact pressure distribution.
Solution Approach 2:
The patent applies counter boring to the pressurizing surface at the outer circumferential regions. This creates localized recesses that concentrate pressure at the outer edges where it is needed most, compensating for the natural pressure gradient that decreases from center to periphery in spherical pressurization.
2Ease of manufacture
If a press pack semiconductor device with a notch portion is pressurized, then the notch portion causes decreased pressure application, but uniform pressurization is difficult to achieve and thermal destruction risk increases at the outer circumferential surface
Solution Approach 1:
The counter boring feature creates localized pressure concentration zones at the outer circumferential surfaces. This compensates for pressure loss in regions with notch portions by directing additional pressure to areas that need it most, ensuring uniform overall pressurization despite structural variations.
3Reliability
If metal fittings for insulating plate with counter boring are used to apply pressure to the outer circumferential surface, then thermal destruction is prevented, but the overall pressure distribution uniformity across the device remains challenging
Solution Approach 1:
The metal fittings for insulating plate act as intermediary elements between the pressurizing body and the semiconductor device. The counter boring in these fittings creates localized pressure application points at the outer circumferential surfaces, preventing thermal destruction while the overall spherical pressurizing body maintains general pressure uniformity.
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
The solution ensures uniform pressurization of semiconductor devices, regardless of notch presence, thereby preventing thermal destruction by equalizing pressure distribution across the device stack.
Implementation Method 1
metal fittings for insulating plate each distributing a pressure applied by the pressuring body to an outer circumferential surface
Implementation Method 2
conical or spherical pressurizing bodies
Data Source
Figure 1
Figure 2(1)~2(2)
Figure 3(1)~3(2)
AI summary
To provide a pressure contact type semiconductor device stack which can uniformly pressurize pressure contact type semiconductor devices irrespective of presence or absence of a notch portion of the pressure contact type semiconductor device, and can prevent thermal destruction of the relevant pressure contact type semiconductor device. Pressurizing means for pressurizing between pressure contact type semiconductor devices and heat sinks which have been stacked is provided with pressuring bodies arranged at the upper and lower surfaces, metal fittings for insulating plate each for distributing a pressure applied by the pressuring body to an outer circumferential surface, and insulating plates each for pressuring the relevant heat sinks by the pressure applied to a pressurizing surface of the relevant metal fitting for insulating plate, and when the pressure contact type semiconductor device has a notch portion at a part of a peripheral portion of a post surface of any one of a collector post surface or an emitter post surface, the pressurizing means is provided with means for making a distance from a pressurizing surface of the metal fitting for insulating plate pressurized by the upper surface pressurizing body to a front surface of a chip equal to a distance from a pressurizing surface of the metal fitting for insulating plate pressurized by the lower surface pressurizing body to a back surface of a chip.