Semiconductor Device Double-Sided Cooling Lead Frame
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Solution Overview
Problem
Discrete package semiconductor devices are limited by single-sided cooling, which restricts their power density and functionality.
Innovation Solution
The implementation of semiconductor devices with multiple exposed die pads on different surfaces allows for double-sided cooling, achieved through a lead frame structure where two lead frames with die pads are stacked before encapsulation, enabling increased power density without modifying die and wire bonding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-sided cooling is used in discrete package semiconductor devices, then the device structure is simple, but the power density and functionality are limited
Solution Approach 1:
The patent transitions from single-sided cooling to double-sided cooling by utilizing both surfaces of the package, effectively adding a dimensional aspect to heat dissipation. Two lead frames with die pads are stacked and encapsulated, allowing heat to be removed from both the top and bottom surfaces of the semiconductor device, thereby doubling the cooling capacity and enabling higher power density without proportionally increasing device complexity.
2Power
If double-sided cooling is implemented with stacked lead frames, then power density increases, but device complexity increases
Solution Approach 1:
The patent combines two lead frames with die pads into a single encapsulated structure, merging their cooling functions while maintaining individual die pad exposure on opposite surfaces. The encapsulation material integrates both lead frames, semiconductor chips, and interconnect structures into one unified package, achieving double-sided cooling without requiring separate cooling systems or complex external modifications.
Solution Approach 2:
The lead frame structure serves multiple functions simultaneously: it provides mechanical support, electrical interconnection, and dual-sided heat dissipation. The same lead frames that carry electrical signals also serve as thermal pathways, and the encapsulation material both protects the internal components and facilitates heat removal from both surfaces, reducing the need for additional specialized components.
3Area of moving object
If die pads are exposed on both surfaces, then usable chip area doubles, but manufacturing complexity increases
Solution Approach 1:
The die pads are prepared and positioned on both lead frames before encapsulation, with alignment features and bonding surfaces pre-configured. The lead frames are stacked in the correct orientation with die pads facing opposite directions, and all electrical interconnections are established before the final encapsulation step, simplifying the overall manufacturing process despite the increased final product complexity.
Data Source
AI summary
A semiconductor device includes a first lead frame, a second lead frame, a first semiconductor chip, and an encapsulation material. The first lead frame includes a first die pad having a first surface and a second surface opposite to the first surface. The second lead frame includes a second die pad having a first surface and a second surface opposite to the first surface. The first surface of the second die pad faces the first surface of the first die pad. The first semiconductor chip is attached to the first surface of the first die pad. The encapsulation material encapsulates the first semiconductor chip and portions of the first lead frame and the second lead frame. The encapsulation material has a first surface aligned with the second surface of the first die pad and a second surface aligned with the second surface of the second die pad.