Semiconductor Edge Termination Layout for Moisture-Resistant Insulation
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Solution Overview
Problem
The front surface protective film and sealing materials in semiconductor devices, particularly under high humidity, are prone to moisture absorption, leading to deposition reactions that can crack or peel, compromising the insulation reliability by creating leakage paths.
Innovation Solution
A semiconductor device design featuring a termination well region and an outer peripheral wire layer configuration that reduces electric field strength and moisture-induced reactions, enhancing insulation reliability by positioning the outer peripheral wire layer to cover the termination well region and connecting it to the front surface electrode through an interlayer insulation film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a front surface protective film made of polyimide or gel is used to cover the front surface electrode, then the electrode is protected from environmental damage, but the protective film absorbs moisture under high humidity leading to deposition reactions, cracks, and peeling that degrade insulation reliability
Solution Approach 1:
The patent introduces an outer peripheral wire layer as an intermediary element positioned between the front surface electrode and the protective film. This wire layer serves as a mediator that reduces the direct interaction between moisture absorbed by the protective film and the front surface electrode, thereby preventing deposition reactions and maintaining insulation reliability even when the protective film absorbs moisture under high humidity conditions.
Solution Approach 2:
The patent segments the protective structure into multiple functional layers: the front surface electrode, the outer peripheral wire layer, and the protective film. By dividing the system into separate functional components with the outer peripheral wire layer positioned between the electrode and protective film, the patent isolates the electrode from moisture-related damage while maintaining the protective function of the film.
2Reliability
If the front surface electrode extends to the outer periphery to maximize electrical connection area, then electrical performance is improved, but electric field concentration at the electrode ends causes breakdown and reduces insulation reliability
Solution Approach 1:
The outer peripheral wire layer acts as an intermediary that distributes and reduces electric field concentration at the ends of the front surface electrode. By positioning this conductive layer between the electrode end and the protective film, the patent creates a field-distributing structure that prevents electric field concentration while maintaining electrical connectivity.
Solution Approach 2:
The patent modifies the electrical parameters at the electrode periphery by introducing the outer peripheral wire layer with specific conductivity characteristics. This changes the electric field distribution pattern from concentrated to distributed, reducing the maximum electric field strength at critical points while maintaining overall electrical performance.
3Area of stationary object
If the outer peripheral wire layer is positioned close to the front surface electrode to minimize space, then device compactness is improved, but moisture and electric field effects still reach the electrode causing deposition and peeling
Solution Approach 1:
The outer peripheral wire layer serves as a protective intermediary that can be positioned close to the front surface electrode while still providing effective protection. Its strategic positioning and conductive properties create an electromagnetic and physical barrier that prevents moisture and electric field effects from directly reaching the electrode, even in compact configurations.
Solution Approach 2:
The patent applies local quality enhancement by positioning the outer peripheral wire layer specifically at critical regions where moisture and electric field effects are most problematic. This localized protection strategy provides targeted shielding at the electrode periphery without requiring comprehensive coverage that would increase device footprint.
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
This configuration effectively reduces the generation of deposited materials and cracks or peeling at the front surface electrode, thereby enhancing the insulation reliability of the semiconductor device by minimizing leakage current and air discharge.
Implementation Method 1
an electric field generated when a reverse voltage is applied to a main electrode of the semiconductor device is reduced by a depletion layer formed by a pn junction between the n-type semiconductor layer and the p-type guard ring region
Implementation Method 2
a depletion layer formed by a pn junction between the n-type semiconductor layer and the p-type guard ring region
Implementation Method 3
The front surface protective film made of polyimide or the like and the sealing material such as gel described above are liable to contain moisture under a high humidity environment
Data Source
AI summary
In a semiconductor device, a semiconductor substrate is divided into an inner region in which an active region is provided and an outer region surrounding the inner region. The semiconductor device includes a semiconductor layer of a first conductivity type, a termination well region of a second conductivity type selectively provided in an upper layer portion of the semiconductor layer to surround the inner region, an impurity region selectively provided in an upper layer portion of the termination well region, a front surface electrode, a back surface electrode, an insulation film being provided to partially cover a top of the termination well region, an outer peripheral wire layer surrounding the inner region, at least a part of which is provided on the insulation film, and an interlayer insulation film at least covering the insulation film and the outer peripheral wire layer.