DTSCR ESD Protection Circuit for Thin-Oxide CDM Robustness
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Solution Overview
Problem
Advanced semiconductor manufacturing processes face challenges in electrostatic discharge (ESD) protection due to the breakdown voltage of the oxide layer being less than that of the junction, leading to ineffective CDM electrostatic protection in conventional designs.
Innovation Solution
The implementation of DTSCR circuits and diodes between the internal circuit and power supply/ground pads provides a bidirectional electrostatic discharge path, ensuring that the oxide layer of the MOS device is not compromised during ESD events, thereby enhancing the electrostatic protection capability of the chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional CDM electrostatic protection circuit is used with MOS devices, then electrostatic protection is provided, but the oxide layer of the input buffer MOS device breaks down before the protection MOS device when ESD occurs
Solution Approach 1:
The patent changes the breakdown voltage parameter relationship by using a non-MOS device (such as a diode or SCR) for electrostatic protection instead of a MOS device. This alternative device type has different electrical characteristics, specifically a higher breakdown voltage than the input buffer's oxide layer, thereby preventing premature oxide layer breakdown during ESD events while maintaining protection functionality.
2Productivity
If advanced manufacturing processes are used to shorten channel length and reduce oxide thickness, then device performance is improved, but the ESD protection design window shrinks
Solution Approach 1:
The patent introduces an intermediary protection device between the input buffer and the ESD source. This intermediary device (non-MOS type) acts as a mediator that handles the ESD stress, preventing it from reaching and damaging the thin oxide layer of the input buffer. This allows advanced process benefits to be retained while ESD protection is maintained through the intermediary's higher breakdown voltage characteristic.
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 solution effectively prevents the breakdown of the oxide layer during ESD, ensuring reliable electrostatic protection and maintaining normal operation of the input circuit, even in advanced manufacturing processes where the oxide layer's breakdown voltage is lower than the junction's.
Implementation Method 1
an electrostatic discharge (ESD) design
Implementation Method 2
a breakdown voltage of an oxide layer of a Metal Oxide Semiconductor (MOS) device
Data Source
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AI summary
An electrostatic protection circuit connected with an internal circuit is provided. The electrostatic protection circuit includes: a first circuit, a first diode connected in parallel with the first circuit, a second circuit, and a second diode connected in parallel with the second circuit. The first circuit is connected between a power supply pad and an internal circuit input terminal. The second circuit is connected between the internal circuit input terminal and a ground pad. The first circuit and the second circuit are diode-triggered silicon controlled rectifier circuits. The technical solution of the disclosure can improve electrostatic protection capability of a charged device model of a chip.