Printed Circuit Board Thermal Management via Microvias and Carbon Resistors
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Solution Overview
Problem
Existing printed circuit boards face limitations in high-temperature environments and mechanical stress, with ceramic substrate-based solutions being costly and complex, while microvia heat dissipation technologies are not suitable for temperatures above 120°C.
Innovation Solution
Combining microvia heat dissipation technology with printed carbon-polymer resistors on the rear side of the printed circuit board, which allows for effective heat dissipation and higher integration density, enabling use in temperatures above 125°C without the need for clean room conditions or unpackaged components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If microvia heat dissipation technology is used, then heat dissipation performance is improved, but temperature resistance is limited to below 120°C
Solution Approach 1:
The patent combines microvia heat dissipation technology with printed carbon-polymer resistors on the rear side of the circuit board. This merging of two different technologies (microvia through-platings for heat dissipation and printed carbon-polymer resistors for temperature resistance) creates a hybrid solution that achieves both effective heat dissipation and high temperature resistance (>125°C), resolving the contradiction between heat dissipation performance and temperature resistance limitation
Solution Approach 2:
The invention uses composite material structures including copper through-platings filled with conductive adhesive, carbon-polymer resistors printed on the rear side, and multiple layers of insulating and conductive materials. This composite approach integrates materials with different properties (thermal conductivity, temperature resistance, electrical conductivity) to simultaneously achieve heat dissipation and high-temperature operation capability
2Temperature
If ceramic substrates with thick-film hybrid technology are used, then temperature resistance above 120°C is achieved, but integration density is low
Solution Approach 1:
The patent transitions from traditional planar circuit board design to a multi-layered three-dimensional structure with insulating outer layers, conductor layers, and embedded microvias. This dimensional evolution allows for higher integration density by utilizing vertical space and multiple stacking layers, while maintaining the temperature resistance benefits of ceramic-like materials through the use of printed carbon-polymer resistors and thermally conductive adhesives
3Temperature
If low-temperature co-fired ceramics are used, then high temperature resistance is achieved, but production cost is high
Solution Approach 1:
The invention replaces expensive low-temperature co-fired ceramics with a more cost-effective combination of standard circuit board materials, printed carbon-polymer resistors, and thermally conductive adhesives. This substitution uses cheaper, easily manufacturable materials and processes (printing and bonding) to achieve comparable high-temperature resistance, significantly reducing production costs while maintaining performance
Solution Approach 2:
The patent replaces complex mechanical ceramic firing processes with simpler printing and bonding operations. Instead of requiring high-temperature co-firing of ceramic layers, the invention uses printed carbon-polymer resistor patterns and thermally conductive adhesive bonding, which are less complex, more cost-effective manufacturing processes that achieve similar high-temperature resistance outcomes
4Quantity of substance
If unpackaged integrated circuits with thin-wire bonding are used, then high integration density is achieved, but production complexity increases due to clean room requirements
Solution Approach 1:
The patent extracts and eliminates the need for unpackaged integrated circuits and thin-wire bonding technology from the design. By using packaged components mounted on a circuit board with printed carbon-polymer resistors and microvia heat dissipation, the invention removes the requirement for clean room environments and complex wire bonding processes, thereby reducing production complexity while maintaining integration density through the printed circuit board architecture
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 provides a cost-effective, high-density interconnect circuit board capable of operating in temperatures above 125°C, with effective heat dissipation and reduced production complexity, suitable for motor vehicle control units.
Implementation Method 1
heat dissipation means which have these microvias being provided for heat dissipation from a component side of the printed circuit board to a rear side of the printed circuit board opposite the component side
Implementation Method 2
the rear side can be contacted in a thermally conductive manner with a heat sink in order to cool the printed circuit board
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a printed circuit board (1) having a component side (10) and a rear side (4) that lies opposite the component side (10). The surface of the rear side (4) is designed substantially in a flat manner such that the rear side (4) can be thermally conductively contacted with a heat sink (8), in particular on a substantially flat contact face, in order to cool the printed circuit board (1). The printed circuit board (1) also has cooling means (12), which comprise microvias (14, 16, 20, 22) and buried vias (28), for cooling the component side (10) in the direction of the rear side (4). Printed carbon polymer resistors (34, 40) are provided on the component side (10) and/or on the rear side (4) and/or in at least one inner conductor layer (26) of the printed circuit board (1) located between the component side (10) and the rear side (4). The printed circuit board (1) can thus be used at ambient temperatures of greater than 125oC and at the same time can be produced economically. The invention also relates to a control device (50) comprising the printed circuit board (1), a device and a motor vehicle therewith, and methods for producing the printed circuit board (1), the control device (50) and the device.