Semiconductor Electrode Structure for Wafer Warpage Reduction
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Solution Overview
Problem
Semiconductor wafers used in power semiconductor devices can warp due to stress caused by metal films during manufacturing, making it difficult to produce reliable devices.
Innovation Solution
Incorporating an insulator between the metal layers of the electrode structure in the semiconductor device to reduce stress and prevent warpage, using a layered metal-insulator configuration that includes a first metal layer, a second metal layer, and an insulator, with the insulator being sandwiched between the metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal films are used in the electrode structure, then electrical conductivity is improved, but stress-induced warpage increases
Solution Approach 1:
An insulator layer is introduced as an intermediary between the first metal layer and the second metal layer. This insulator acts as a stress buffer that mediates the stress generated by the metal films, preventing direct transmission of stress to the semiconductor wafer and thereby reducing warpage while maintaining the electrical functionality of the electrode structure
Solution Approach 2:
The electrode structure is designed as a composite multi-layer system comprising a first metal layer, an insulator layer, and a second metal layer. This composite structure combines materials with different mechanical and electrical properties to achieve both good electrical conductivity and reduced stress-induced warpage
2Ease of manufacture
If metal films are deposited on the semiconductor wafer, then electrode functionality is achieved, but manufacturing precision deteriorates due to warpage
Solution Approach 1:
The insulator layer serves as a mediator between the metal films and the semiconductor wafer, absorbing and distributing stress to maintain wafer flatness during subsequent manufacturing processes, thereby ensuring manufacturing precision is not compromised by warpage
3Device complexity
If stress from metal films is allowed to accumulate, then device structure is simplified, but mechanical strength decreases due to cracks
Solution Approach 1:
The insulator layer acts as a stress buffer that absorbs and distributes mechanical stress, preventing stress concentration that would lead to cracks. This intermediary layer enhances the mechanical strength and reliability of the device by mitigating the harmful effects of stress from the metal films
Solution Approach 2:
The insulator layer is positioned in advance between the metal layers to provide cushioning against stress accumulation. This prior cushioning prevents stress from building up to levels that would cause structural failure or cracking during device operation or manufacturing
Data Source
AI summary
A semiconductor device according to an embodiment includes: a first electrode including a first metal layer, a second metal layer, and an insulator; a second electrode; a semiconductor layer provided between the first electrode and the second electrode; and an insulating layer provided between the first electrode and the semiconductor layer, wherein the first electrode includes a first portion electrically connecting the semiconductor layer and the first electrode, the first portion is provided between one part of the insulating layer and another part of the insulating layer in a cross section parallel to a first direction connecting the first electrode and the second electrode, and the first portion includes the first metal layer in contact with the semiconductor layer, the second metal layer, and the insulator provided between the first metal layer and the second metal layer.