Semi-Insulating Termination Structure for Moisture-Resistant Semiconductors
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Solution Overview
Problem
Existing semiconductor devices face issues with moisture resistance, particularly in high-humidity environments, as fluids entering through gaps in the resin case can corrode aluminum electrodes, affecting the reliability of power IGBT modules.
Innovation Solution
A semiconductor device design featuring a first and second semi-insulating film structure, with a first insulating film covering the impurity region and a second semi-insulating film covering the termination region, along with a polysilicon film to form a two-stage field plate structure, enhancing moisture resistance and withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an aluminum electrode is provided in the termination region close to the resin case inner surface, then the device structure is simplified and manufacturing is easier, but the electrode is easily influenced by fluid entering from the resin case gap, reducing moisture resistance
Solution Approach 1:
A semi-insulating film is introduced as an intermediary layer between the aluminum electrode and the external environment. This film serves as a protective barrier that prevents fluid from directly contacting and corroding the aluminum electrode, while still allowing the electrode to function electrically. The semi-insulating film thus mediates between the need for simple electrode structure and the requirement for moisture resistance.
Solution Approach 2:
The patent uses a thin semi-insulating film layer that provides sufficient protection against moisture while maintaining electrical functionality. This thin protective layer acts as a sacrificial or disposable barrier that prevents fluid penetration to the aluminum electrode without requiring complex structural modifications.
2Volume of moving object
If the aluminum electrode is positioned close to the resin case for compact design, then the device size is reduced, but the electrode becomes more susceptible to fluid corrosion from the resin case gap
Solution Approach 1:
The semi-insulating film serves as a protective intermediary that shields the aluminum electrode from fluid corrosion. This allows the electrode to be positioned close to the resin case for compact design while the film barrier prevents harmful fluid contact, thus resolving the contradiction between compact size and corrosion resistance.
3Device complexity
If a conventional termination structure with aluminum electrode is used, then the manufacturing process is simpler, but the device shows reduced reliability in high humidity environments due to electrode corrosion
Solution Approach 1:
The semi-insulating film is introduced as a protective intermediary layer that maintains the simplicity of the conventional termination structure while adding corrosion protection. This film layer does not significantly increase structural complexity but dramatically improves reliability in high humidity environments by preventing fluid contact with the aluminum electrode.
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
The design significantly improves moisture resistance and withstand voltage, with the semi-insulating films acting as a barrier against corrosion and dispersing electrical field concentration, resulting in improved reliability under high humidity conditions.
Implementation Method 1
a first semi-insulating film covering a region from part of the impurity region which is not covered by the first insulating film to at least a partial upper side of the first insulating film; and a second semi-insulating film covering a region from the first semi-insulating film to a partial upper side of the first main electrode
Implementation Method 2
the semi-insulating films acting as a barrier against corrosion and dispersing electrical field concentration, resulting in improved reliability under high humidity conditions
Data Source
AI summary
A semiconductor substrate includes: an active region; and a termination region surrounding the active region, and the semiconductor device includes: a first main electrode provided on the active region; a second main electrode provided on an opposite side of the first main electrode; an impurity region provided on an outermost periphery of the termination region; a first insulating film provided on an outer end edge part; a second insulating film provided on a region from an inner end edge part of the termination region to an end edge part of the active region; a first semi-insulating film covering a region from part of the impurity region which is not covered by the first insulating film to a partial upper side of the first insulating film; and a second semi-insulating film covering a region from the first semi-insulating film to a partial upper side of the first main electrode.