Trench Shielding Structure for Semiconductor Devices
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Solution Overview
Problem
Current semiconductor devices with shield electrodes face challenges in integration with other structures, including additional masking steps, non-planar topographies, and excessive die area consumption, which impact cost and manufacturability, while also seeking to enhance performance.
Innovation Solution
A shielding structure is formed in closely spaced trenches with insulator layers and shield electrodes connected to ground potential, placed beneath control pad or runner configurations, reducing capacitive effects and gate-to-drain capacitance by optimizing the placement and design of shield electrodes within the semiconductor device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shield electrodes are integrated into trench MOSFET devices, then gate-to-drain capacitance is reduced and switching performance is improved, but device complexity and manufacturing complexity increase due to additional masking steps and non-planar topographies
Solution Approach 1:
The patent combines the shield electrode formation with the existing trench gate formation process. The shield electrode is formed as part of the same trench structure, eliminating the need for separate masking and deposition steps. This merging of functions reduces manufacturing complexity while maintaining the capacitance reduction benefit.
Solution Approach 2:
The trench structure serves multiple functions: it forms the gate electrode, provides mechanical support, and simultaneously houses the shield electrode for capacitance reduction. This multi-functionality approach integrates the shield electrode without requiring additional process steps or increasing device complexity.
2Reliability
If shield electrodes are added to reduce capacitive effects, then switching characteristics are improved, but die area consumption increases
Solution Approach 1:
The patent transitions from planar shield electrode configurations to a vertical three-dimensional trench structure. The shield electrode is positioned within the trench depth, utilizing the vertical dimension rather than consuming additional horizontal die area. This dimensional transition maintains switching performance while preserving die area.
3Reliability
If additional shield electrode structures are incorporated, then gate-to-drain capacitance is reduced, but manufacturing complexity increases due to additional masking steps
Solution Approach 1:
The shield electrode is formed during the same trench etching and filling process as the gate electrode. By combining these two electrode formations into a single process sequence, the patent eliminates additional masking steps while achieving the desired capacitance reduction.
Solution Approach 2:
The shield electrode position and dimensions are predetermined during the trench design phase, allowing it to be formed automatically during standard processing without requiring additional masking or alignment steps. This preliminary planning integrates the shield function into existing manufacturing workflows.
Data Source
AI summary
A shielding structure for a semiconductor device includes a plurality of trenches. The trenches include passivation liners and shield electrodes, which are formed therein. In one embodiment, the shielding structure is placed beneath a control pad. In another embodiment, the shielding structure is placed beneath a control runner.