SMT Power Package Through-Hole Clamping for Heat Sink Contact
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Solution Overview
Problem
The existing power device assembly processes, such as wave soldering, are inefficient and costly due to the complexity of electrical connections and poor heat dissipation efficiency caused by inadequate contact between the power device and the heat sink, leading to high thermal resistance.
Innovation Solution
A power device assembly that includes a power device with a through hole for direct connection to a heat sink via a fastener, eliminating the need for component holes and enhancing heat dissipation by reducing voids between the power device and the heat sink, utilizing a thermally conductive substrate and interface layers for improved thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wave soldering process is used to implement electrical connection between pins and circuit board, then electrical connection is achieved, but processing efficiency is reduced and manufacturing complexity increases
Solution Approach 1:
The patent extracts the pins from the traditional through-hole insertion process and integrates them directly onto the circuit board surface using SMT technology. This eliminates the need for opening component holes and inserting pins, thereby simplifying the assembly process and improving processing efficiency while maintaining electrical connection functionality
Solution Approach 2:
The patent replaces the mechanical insertion and soldering process (wave soldering) with a surface-mount technology process. This substitution changes the assembly methodology from mechanical hole insertion to surface mounting, reducing process complexity and improving manufacturing efficiency
2Temperature
If heat sink is provided for power device in SMT, then heat dissipation structure is established, but thermal contact is insufficient due to tolerance, causing high thermal resistance
Solution Approach 1:
The patent incorporates a through hole extending through the substrate structure and molded package during the manufacturing process, before final assembly. This preliminary action ensures that a fastener can be inserted to mechanically secure the heat sink to the power device, guaranteeing intimate thermal contact and reducing thermal resistance caused by assembly tolerances
Solution Approach 2:
The patent introduces a fastener as an intermediary element that mediates between the heat sink and the power device. This fastener passes through the pre-formed through hole to mechanically connect the heat sink to the substrate, ensuring reliable thermal contact and improving heat dissipation efficiency by eliminating gaps caused by tolerance accumulation
3Strength
If fastener is used to connect circuit board and heat sink externally, then power device is sandwiched between them, but large voids remain between power device and heat sink
Solution Approach 1:
The patent moves the fastener connection from an external peripheral connection to an internal through-hole connection. By passing the fastener through the substrate structure and molded package via a through hole, the connection is established in the vertical dimension through the device, ensuring intimate contact between the heat sink and the power device substrate, thereby eliminating large voids while maintaining mechanical strength
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 solution simplifies the assembly process, reduces manufacturing costs, and significantly improves heat dissipation efficiency by ensuring close contact between the power device and the heat sink, addressing the limitations of existing technologies.
Implementation Method 1
the power device is provided with the through hole that extends through the substrate structure and the molded package and is configured to pass through a fastener, to fixedly connect the circuit board, the power device, and the heat sink
Implementation Method 2
a heat sink needs to be provided for the power device to dissipate heat... increasing an area of fitting between the heat dissipation surface of the power device and an assembling surface of the heat sink, and reducing voids on an interface... thereby reducing a thermal resistance
Data Source
Figure 1~3
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Figure 7a~7b
AI summary
This application provides a power device, a power device assembly, and a related apparatus. The power device includes a package body and a plurality of pins. The package body includes a substrate structure, a semiconductor die, and a molded package. The semiconductor die is disposed on the substrate structure. The substrate structure includes a heat dissipation surface to be connected to a heat sink. A first end of each of the pins is fixed to the substrate structure. The molded package covers the semiconductor die and the substrate structure except the heat dissipation surface. A second end of each of the pins and the heat dissipation surface are both exposed from the molded package. The second end of each of the pins includes a mounting surface to be mounted to a circuit board through a surface-mount technology for an electrical connection. The power device is further provided with a through hole extending through the substrate structure and the molded package. An inner wall of the through hole is covered with the molded package. A fastener passes through the through hole and the heat sink for a fixed connection between the heat dissipation surface and the heat sink, so that the power device is crimped onto the heat sink, which facilitates reduction of voids on an interface between the power device and the heat sink, thereby improving the heat dissipation efficiency.