Semiconductor Electrode Filling Strategy for Terminal Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power semiconductors, the formation of fine terminal regions is hindered by thick electrode film thicknesses, leading to electrode fall-downs, cracks in protective films, and local current concentration, which reduces reliability due to external package stress and potential disconnection.
Innovation Solution
A semiconductor device design where the first electrode does not completely fill the contact hole in the main cell region, while the second electrode completely fills the contact hole in the terminal region, both made of the same material, with a third electrode filling the first contact hole, reducing height differences and current concentration, and using a semi-insulating film for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick AlSi electrode is used to fill the contact hole in the main cell region, then large current can flow vertically, but electrode fall-down and crack in protective film occur due to stress from external package
Solution Approach 1:
The patent applies different filling strategies to different contact holes based on their location and function. The first contact hole in the main cell region is partially filled to reduce stress, while the second contact hole in the terminal region is completely filled to ensure current carrying capacity. This local differentiation resolves the contradiction between mechanical strength and reliability.
Solution Approach 2:
The electrode structure is segmented into multiple parts: a first electrode in the first contact hole, a second electrode in the second contact hole, and a third electrode on top of the first electrode. This segmentation allows each electrode to be optimized for its specific function, with the third electrode providing additional current path without requiring the first electrode to be excessively thick.
2Area of stationary object
If fine terminal region is formed to reduce ineffective region, then device area is reduced, but electrode fall-down and crack occur due to large film thickness and high aspect ratio
Solution Approach 1:
The patent implements local quality by completely filling the second contact hole in the terminal region with the second electrode, ensuring robust current path and preventing electrode fall-down in the fine-pitched terminal area. This localized complete filling maintains reliability while allowing the terminal region to be made finer.
3Manufacturing precision
If electrode is made thin to enable fine patterning, then fine terminal region can be formed, but local current concentration and disconnection occur
Solution Approach 1:
The current path is segmented across multiple electrodes: the first electrode provides initial current conduction, the third electrode on top provides additional current path, and the second electrode in the terminal region ensures robust connection. This segmentation allows thin individual electrodes that can be precisely patterned while maintaining overall current conduction reliability through the combined effect of multiple electrodes.
Data Source
AI summary
A semiconductor device includes; a semiconductor substrate including a major surface; a first diffusion region in the major surface in a main cell region; a second diffusion region in the major surface in a terminal region; an insulating film on the major surface and having first and second contact holes on the first and second diffusion regions respectively; a first electrode in the first contact hole and connected to the first diffusion region; a second electrode in the second contact hole and connected to the second diffusion region; a semi-insulating film covering the second electrode; and a third electrode on the first electrode, wherein the first and second electrodes are made of the same material, the first electrode does not completely fill the first contact hole, the second electrode completely fills the second contact hole, and the third electrode completely fills the first contact hole.