Power Semiconductor Package Cooling With Spacer-Controlled Solder Layer
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Solution Overview
Problem
Power semiconductor components face challenges in efficiently dissipating heat, particularly in high-power applications like electric vehicle chargers, where traditional cooling methods like thermal drilling are restricted by electrical insulation regulations.
Innovation Solution
A power semiconductor component design featuring a metal heat sink exposed on a plastic housing, connected to a wiring substrate with a large thermal conductivity copper layer via a solder layer and spacers, allowing for increased solder mass and effective heat dissipation, with the option of using vias for through-hole technology or surface-mountable configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal drilling is used for heat dissipation, then heat dissipation efficiency is improved, but electrical insulation regulations cannot be met
Solution Approach 1:
The heat dissipation path is segmented into multiple independent components: the wiring substrate with copper heat dissipation region, the solder layer, the spacers, and the heat sink on the power semiconductor package. This segmentation allows each component to fulfill its function without compromising electrical insulation, as the thermal path is separated from electrical conductors.
Solution Approach 2:
Non-conductive spacers are introduced as intermediary elements between the heat sink and the copper heat dissipation region. These spacers serve dual purposes: they maintain the necessary electrical insulation while allowing thermal energy to transfer from the heat sink to the copper layer, thus resolving the contradiction between heat dissipation efficiency and electrical insulation.
2Temperature
If solder layer thickness is increased for better heat dissipation, then heat dissipation efficiency is improved, but the distance between package and wiring substrate increases
Solution Approach 1:
Non-conductive spacers act as intermediary elements that enable the solder layer to be thicker without increasing the overall distance between the package and wiring substrate. The spacers are positioned at the edges, allowing the center area to have sufficient solder thickness for heat dissipation while maintaining compact overall dimensions.
Solution Approach 2:
The spacers are positioned at the peripheral edges of the heat dissipation region, utilizing the vertical dimension at the boundaries to maintain electrical insulation and structural support, while the central horizontal area maximizes solder layer thickness for optimal thermal conduction from the heat sink to the copper layer.
3Temperature
If solder mass is increased for better heat dissipation, then heat dissipation efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process leverages the existing through-hole via structure to automatically guide and contain the solder material. When solder paste is applied and reflowed, the via holes self-align to receive the solder, which then flows down to fill the space between the heat sink and copper layer. This self-service mechanism eliminates the need for complex manual solder application processes.
Solution Approach 2:
Solder paste is applied in advance to the heat dissipation region before the final assembly step. The spacers are pre-positioned to define the solder distribution area. During the reflow process, the solder automatically flows to the correct locations and quantities, eliminating the need for precise real-time control during assembly and reducing 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 significantly enhances heat dissipation by increasing the solder mass and thermal conductivity, effectively managing short-term power peaks and improving heat spreading, thus ensuring efficient cooling in constrained electrical environments.
Implementation Method 1
The housing is positioned on the wiring substrate such that the heat sink is connected to the cooling region via a solder layer
Implementation Method 2
A number of spacers, located between the heat sink and the cooling region, are embedded in the solder layer
Implementation Method 3
A heat dissipation region with increased thermal conductivity is arranged on the second main surface. For example, the heat dissipation region is formed by a copper layer of the circuit board arranged on the second main surface of the wiring substrate
Data Source
Figure 1~2
AI summary
Disclosed is a power semiconductor component (1), having - a power semiconductor component part (2) provided inside a housing (4), a heat sink (6) being exposed on a first surface (5) of the housing (4); - a wiring substrate (10) that holds the housing (4) comprising the power semiconductor component part (2), said substrate having a first main surface (12) and a second main surface (14), and a heat extraction region (16) with increased thermal conductivity being provided on the second main surface (14); wherein the housing (4) is provided on the wiring substrate (10) such that the heat sink (6) is connected to the heat extraction region (16) via a solder layer (20), and a number of spacers (28), provided between the heat sink (6) and the heat extraction region (16) are embedded in the solder layer (20). A method for producing a power semiconductor component is also disclosed.