Power Converter Package Layout for Isolation and Heat Dissipation
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Solution Overview
Problem
Existing power converter package structures face challenges in achieving high voltage isolation between power devices and control circuits, leading to potential incorrect operation and leakage current, while also compromising heat dissipation and increasing manufacturing costs due to parallel die pad arrangement and extended bonding wire lengths.
Innovation Solution
A package structure for power converters is designed with a die pad, insulation adhesive layers formed using wafer backside coating (WBC) and dispensing processes, and conductive adhesive layers to isolate power and control circuit dies, utilizing a leadframe for improved heat dissipation and reduced bonding wire lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If power devices and control circuit are encapsulated in a single package structure, then the volume of the power supply can be decreased, but high voltage isolation between power devices and control circuits becomes difficult to achieve
Solution Approach 1:
The adhesive layer is segmented into two distinct layers: a first adhesive layer (conductive) between the power device die and die pad, and a second adhesive layer (insulative) between the control circuit die and die pad. This segmentation allows both power devices and control circuit to be encapsulated in a single package while maintaining high voltage isolation between them, resolving the contradiction between miniaturization and electrical isolation.
2Ease of manufacture
If parallel die pad arrangement is used, then manufacturing can be simplified, but bonding wire lengths are extended leading to increased costs
Solution Approach 1:
The patent transitions from a planar parallel arrangement of die pads to a stacked three-dimensional arrangement where the control circuit die is positioned above the power device die. This dimensional change allows both dies to be connected to the same die pad area, significantly reducing bonding wire lengths while maintaining ease of manufacture through the standardized adhesive layer application process.
3Reliability
If insulation adhesive layer is used to separate power and control circuit, then high voltage isolation is achieved, but heat dissipation performance deteriorates
Solution Approach 1:
The adhesive structure exhibits local quality differentiation: the second adhesive layer (between control circuit die and die pad) provides high voltage isolation with insulative properties, while the first adhesive layer (between power device die and die pad) provides conductive properties for efficient heat dissipation. This localized functional differentiation allows simultaneous achievement of electrical isolation and thermal management.
Data Source
AI summary
A package structure of a power converter, can include: a die pad; an insulation adhesive layer and a conductive adhesive layer on the die pad; a control circuit die on the insulation adhesive layer, where the insulation adhesive layer comprises a first insulation adhesive layer on a back surface of the control circuit die, and a second insulation adhesive on a surface of the die pad, where the first insulation adhesive layer is connected to the second insulation adhesive layer; and a power device die on the conductive adhesive layer, where the insulation adhesive layer is separated from the conductive adhesive layer.