Semiconductor Isolation Structure with Varying Thickness
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Solution Overview
Problem
Improving semiconductor devices, such as low-side and high-side switches, is challenging due to the need for electrical isolation of different parts, sufficient thermal coupling between the source and heat sink, and reduction of parasitic inductances in a semiconductor body.
Innovation Solution
A semiconductor device with a first and second load terminal contact area and a control terminal contact, where an isolation structure extends through the semiconductor body to electrically isolate different parts, with varying thicknesses and isolation parts formed using trench and mask pattern processes to optimize functional elements and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolation structure extends through the entire semiconductor body, then electrical isolation between different parts is improved, but mechanical strength is reduced
Solution Approach 1:
The isolation structure is implemented with varying thickness throughout the semiconductor body. In regions requiring electrical isolation (such as between different transistor structures), the isolation structure extends fully through the substrate. In regions requiring mechanical strength (such as under contact areas or in support regions), the isolation structure has reduced thickness or is absent, allowing the semiconductor substrate to maintain its structural integrity.
2Productivity
If the semiconductor body is thinned for rear side processing, then integration density is improved, but mechanical strength and dicing stability are reduced
Solution Approach 1:
Different regions of the semiconductor body have different thicknesses. The active device regions are thinned to enable rear side processing and improve integration density, while specific support regions maintain greater thickness to provide mechanical strength and stability during dicing and handling. This selective thickness variation allows simultaneous achievement of high integration density and processing stability.
3Temperature
If thermal coupling between source and heat sink is enhanced, then thermal management is improved, but electrical isolation between different parts may be compromised
Solution Approach 1:
The isolation structure is divided into multiple segments or layers with different functions. Certain isolation regions are designed with higher thermal conductivity to enhance heat dissipation paths from active devices to heat sinks, while other isolation regions maintain high electrical resistance for electrical isolation. This segmented approach allows simultaneous optimization of thermal management and electrical isolation through material selection and structural design.
Data Source
AI summary
An embodiment of a semiconductor device comprises a first load terminal contact area at a first side of a semiconductor body. A second load terminal contact area is at a second side of the semiconductor body opposite to the first side. A control terminal contact area is at the second side of the semiconductor body. An isolation structure extends through the semiconductor body between the first and second sides. The isolation structure electrically isolates a first part of the semiconductor body from a second part of the semiconductor body. A first thickness of the first part of the semiconductor body is smaller than a second thickness of the second part of the semiconductor body.