Multilayer Passivation Stack for Humidity-Resistant Semiconductor Edges
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Solution Overview
Problem
Conventional passivation layers on semiconductor devices degrade in humid and hot environments, leading to corrosion and a reduction in voltage blocking capability, necessitating a more robust mechanical and chemical solution.
Innovation Solution
A multi-layer passivation stack comprising an oxide, nitride, and imide layers is applied to the semiconductor device, with specific thicknesses and configurations to protect the surface from humidity and corrosion, including a layer stack with a first layer of oxide, a second layer of nitride, and a third layer of imide, each with distinct edge alignments to enhance corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional passivation layer is applied to protect the semiconductor surface, then the surface is protected from corrosion, but the passivation layer degrades in humid and hot environments leading to corrosion and reduced voltage blocking capability
Solution Approach 1:
The patent applies a multi-layer composite passivation structure consisting of different materials (oxide layer, nitride layer, and imide layer) with complementary properties. Each layer provides specific protection mechanisms, and their combination creates a synergistic effect that prevents corrosion while maintaining stability in humid and hot environments, thereby resolving the contradiction between corrosion resistance and long-term compositional stability.
Solution Approach 2:
The passivation layer is segmented into multiple distinct layers (oxide, nitride, imide) rather than using a single conventional layer. This segmentation allows each layer to perform its specific function optimally and prevents the degradation issues that affect single-layer passivation structures in harsh environments.
2Reliability
If a passivation layer is formed on the semiconductor body surface, then voltage blocking capability is maintained, but the passivation layer may cause corrosion under certain environmental conditions
Solution Approach 1:
The multi-layer composite structure with oxide, nitride, and imide layers provides enhanced protection against environmental corrosion while maintaining the necessary electrical properties for voltage blocking. The combination of materials with different chemical and physical properties creates a more robust barrier that prevents harmful environmental factors from reaching the semiconductor body.
Solution Approach 2:
Different layers in the passivation structure are positioned to address specific local requirements: the oxide layer provides initial protection and adhesion, the nitride layer offers chemical inertness and barrier properties, and the imide layer provides additional environmental stability. This local differentiation of material properties optimizes protection against corrosion while preserving voltage blocking capability.
Data Source
AI summary
A semiconductor device includes a semiconductor body comprising a first surface and an edge surface, a contact electrode formed on the first surface and comprising an outer edge side, and a passivation layer section conformally covering the outer edge side of the contact electrode. The passivation layer section is a multi-layer stack comprising a first layer, a second layer, and a third layer. Each of the first, second and third layers include outer edge sides facing the edge surface and opposite facing inner edge sides. The outer edge side of the contact electrode is disposed laterally between the inner edge sides and the outer edge sides of each layer.