PCB-Embedded Half-Bridge Cell With Integrated RC Snubber Decoupling
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Solution Overview
Problem
Existing power module packaging technologies face challenges in providing effective sealing, electrical connections, thermal management, and reducing parasitic elements, especially in prepackages used for buck/boost designs, which are inflexible and have high parasitic elements.
Innovation Solution
A semiconductor package is proposed with a pair of power switch dies connected in series, embedded in a PCB with a silicon RC snubber die, using vias for interconnections and a decoupling function, integrated into a PCB with copper layers and epoxy laminate layers to form a prepackaged half bridge switching cell, which includes vias for connections and cooling surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power devices are embedded in a multilayer PCB laminate with vias for interconnection, then electrical connections and thermal paths are provided, but parasitic elements remain high and switching transitions are not clean
Solution Approach 1:
The patent combines the RC snubber circuit with the power device embedding structure by integrating capacitor plates into the PCB laminate layers. The capacitor plates are formed within the epoxy laminate layers themselves, merging the decoupling function with the structural substrate, thereby reducing parasitic elements and providing cleaner switching transitions.
Solution Approach 2:
The patent introduces an intermediary RC snubber circuit with capacitor plates embedded in the PCB laminate to mediate between the power devices and the external circuitry. This intermediary structure provides local decoupling and filters high-frequency noise, reducing EMI and improving switching transition quality without requiring external components.
2Reliability
If RC snubber components are added to reduce parasitic elements and improve switching transitions, then EMI noise and overshoots are reduced, but device complexity and packaging difficulty increase
Solution Approach 1:
The patent merges the RC snubber circuit with the PCB laminate structure by forming capacitor plates within the epoxy layers and using the same vias for both mechanical support and electrical connection. This integration eliminates the need for separate snubber component packages, reducing overall device complexity while maintaining the decoupling function.
Solution Approach 2:
The PCB laminate structure serves multiple functions simultaneously: it provides mechanical support for embedded power devices, creates electrical connections through vias, forms capacitor plates for the RC snubber circuit, and provides thermal management paths. This multi-functionality reduces the need for additional components and simplifies the overall package structure.
3Adaptability or versatility
If conventional prepackages are used for buck/boost designs, then single semiconductor prepackages are provided, but flexibility is limited and parasitic elements remain high
Solution Approach 1:
The patent segments the prepackage into multiple functional layers within the PCB laminate, with separate regions for power devices, RC snubber circuits, and interconnection vias. This segmentation allows independent optimization of each function while maintaining overall flexibility for different buck/boost design configurations and reduces parasitic elements through localized decoupling.
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 integrated silicon RC snubber die limits stray elements, providing cleaner switching transitions, reduces EMI noise and overshoots, and allows for compact PCB layouts with improved temperature stability and sensing capabilities.
Implementation Method 1
The RC snubber near decoupling has the advantage of containing the switching loop to the close vicinity of power devices thus limiting the impact of stray elements located outside.
Implementation Method 2
first vias in the PCB interconnect connection pads of the dies and connection pads of said RC snubber component with tracks made in at least one of said top copper layer and said bottom copper layer
Implementation Method 3
at least some tracks on said bottom layer providing cooling surfaces for said package
Data Source
Figure 1~3
Figure 2A~2B
Figure 4
AI summary
Semiconductor package (1) comprising at least a pair of power switch dies (11, 12) connected in series to form a half bridge switching CELL, said pair of power dies being connected in parallel with one or more RC snubber die (13) with a silicon substrate, said power switch dies and RC snubber die being embedded in a PCB (20) comprising a top copper layer (21), PCB epoxy laminate layers (22, 24) and a bottom copper layer (23) for forming a prepackaged half bridge switching cell, wherein first vias (33, 34, 35, 36, 37) in the PCB (22) interconnect connection pads of the dies and connection pads of said RC snubber component with tracks (S2h, S2, D2S1, D1, 51) made in at least one of said top copper layer and said bottom copper layer and wherein second vias (31, 32) to interconnect tracks on said top copper layer and tracks on said bottom copper layer, at least some tracks on said top copper layer providing further connection pads on said top copper layer to connect said semiconductor package to a further PCB, at least some tracks on said bottom layer providing cooling surfaces for said package.