Semiconductor Integrated Circuit Device Abnormal Voltage Protection
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Solution Overview
Problem
Conventional protective circuits for semiconductor integrated circuits with multiple power supply systems struggle to effectively protect against abnormal voltages due to a narrow design window between clamping voltage and breakdown voltage, particularly in ultra-thin film transistors, where the signal line protective circuit's clamping voltage has a significant influence, leading to potential gate oxide breakdown.
Innovation Solution
A semiconductor integrated circuit device with a first and second power supply system, a signal line, a discharge path for abnormal current, a detecting circuit to measure potential differences, and a signal line protective circuit that operates based on detected thresholds to suppress voltage increases on the signal line, using MOS transistors and diodes or resistors to manage abnormal currents and prevent breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional protective circuit using snap-back operation of MOS parasitic bipolar transistor is used, then the signal line is protected against abnormal voltage, but the gate oxide film is more likely to break before the start of snap-back operation in ultra-thin film transistors
Solution Approach 1:
The patent introduces a detecting circuit as an intermediary component that monitors the potential difference between power supply lines and triggers the protective circuit before the abnormal voltage reaches harmful levels. The detecting circuit acts as a mediator between the power supply system and the protective circuit, enabling early detection and response to potential breakdown conditions.
Solution Approach 2:
The protective circuit is designed to operate in advance by detecting potential differences that indicate approaching breakdown conditions. The detecting circuit continuously monitors the electrical state and activates the protective mechanism before the gate oxide film breakdown occurs, performing preliminary protection action rather than reactive protection after damage begins.
2Productivity
If the design window between clamping voltage and breakdown voltage is narrowed in 90 nm process, then higher integration is achieved, but the protective circuit becomes less effective as Vclamp and VBD converge
Solution Approach 1:
The patent replaces the conventional voltage-threshold-based protective mechanism with an electrical field-based detection system. Instead of relying on the mechanical snap-back operation of parasitic bipolar transistors, the system uses electric field sensing through the detecting circuit to monitor potential differences and trigger protection, substituting a more sensitive detection mechanism.
Solution Approach 2:
The patent changes the operational parameter from clamping voltage threshold to potential difference detection. By monitoring the potential difference between power supply lines rather than relying on fixed clamping voltage levels, the system can detect abnormal conditions earlier and respond more effectively within the narrowed design window of advanced process nodes.
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 solution effectively raises the level of abnormal voltage that can be withstood by the semiconductor integrated circuit, suppressing signal line voltage increases and preventing gate oxide breakdown, while maintaining normal operation by only activating the protective circuit during abnormal conditions.
Implementation Method 1
a detecting circuit for detecting a potential difference between two positions in the discharge path through which the abnormal current flows
Implementation Method 2
a discharge path which is different from the signal line and through which an abnormal current flows when an abnormal voltage is applied
Data Source
AI summary
A semiconductor integrated circuit device of the invention includes: a first power supply system including a first circuit connected with a first power supply line; a second power supply system including a second circuit connected with a second power supply line; a signal line connected between the first circuit and the second circuit, and transmitting a signal between the first circuit and the second circuit; a discharge path which is different from the signal line and through which an abnormal current flows when an abnormal voltage is applied between the first power supply system and the second power supply system; a detecting circuit for detecting a potential difference between two positions in the discharge path through which the abnormal current flows when the abnormal voltage is generated; and a protective circuit that operates based on an output of the detecting circuit to suppress a voltage increase of the signal line.