Power Semiconductor Terminal Stack for Reliable Encapsulation Bonding
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Solution Overview
Problem
Existing power semiconductor devices face challenges in ensuring a reliable and safe coupling between terminals and encapsulation, which is crucial for insulation and environmental sealing, particularly in high-voltage and high-current applications.
Innovation Solution
The implementation of a copper-silicon-nitride (CuSiN) or copper-germanium-nitride (CuGeN) coupling layer between the atomic layer deposition (ALD) layer and the copper base layer at the load or control terminals, enhancing the adhesion and reliability of the terminal-encapsulation interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a copper base layer is used at the load terminal for electrical conductivity, then electrical conductivity is improved, but adhesion to the encapsulation deteriorates
Solution Approach 1:
The patent employs a composite layer structure comprising a copper base layer, an intermediate coupling layer (e.g., copper-silicon-nitride CuSiN or copper-germanium-nitride CuGeN), and an outer ALD layer. This composite structure combines the high electrical conductivity of copper with the adhesion properties of the intermediate layer, resolving the contradiction between electrical conductivity and adhesion strength at the terminal-encapsulation interface.
Solution Approach 2:
The intermediate coupling layer (CuSiN or CuGeN) acts as a mediator between the copper base layer and the ALD layer/encapsulation. This intermediate layer provides both electrical conductivity pathways and strong bonding interfaces, enabling the copper to maintain its conductivity function while the coupling layer ensures strong adhesion to the encapsulation material.
2Reliability
If an ALD layer is applied at the first side of the load terminal for insulation, then insulation performance is improved, but adhesion to the encapsulation deteriorates
Solution Approach 1:
The patent creates a composite structure where the ALD layer (providing insulation) is combined with the copper-based coupling layers (providing adhesion). The multi-layer composite ensures that the ALD layer maintains its insulation function while the underlying copper and intermediate layers provide strong mechanical adhesion to the encapsulation.
Solution Approach 2:
The copper and copper-nitride layers serve as intermediary bonding layers between the ALD insulating layer and the encapsulation. These intermediary layers ensure that the ALD layer adheres strongly to the encapsulation while maintaining the insulation properties of the ALD layer itself.
3Strength
If a coupling layer comprising copper-silicon-nitride or copper-germanium-nitride is introduced between the ALD layer and the copper base layer, then adhesion is improved, but device complexity increases
Solution Approach 1:
The patent optimizes the parameters of the coupling layer, including its composition (copper-silicon-nitride or copper-germanium-nitride), thickness (e.g., 5-50 nm), and deposition conditions, to achieve maximum adhesion with minimal additional complexity. By carefully controlling these parameters, the coupling layer provides enhanced adhesion while maintaining a relatively simple overall structure that can be integrated into existing manufacturing processes.
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 configuration improves the reliability and safety of the terminal-encapsulation coupling, ensuring effective insulation and environmental sealing, even in high-stress conditions, thereby enhancing the performance and durability of power semiconductor devices.
Implementation Method 1
The first load terminal comprises: at the first side, an atomic layer deposition, ALD, layer
Implementation Method 2
between the ALD layer and the base layer, a coupling layer, wherein the coupling layer comprises copper-silicon-nitride, CuSiN
Data Source
AI summary
A power semiconductor device includes a semiconductor body; a first load terminal at the semiconductor body; and a second load terminal at the semiconductor body. The power semiconductor device is configured to conduct a load current between the first load terminal and the second load terminal. The first load terminal has a first side and a second side adjoining the semiconductor body. The first load terminal includes: at the first side, an atomic layer deposition (ALD) layer; at the second side, a base layer including copper; and between the ALD layer and the base layer, a coupling layer that includes copper-silicon-nitride (CuSiN).