A Dual Mode Electrostatic Discharge Protection I/O Circuit

Abstract

The invention relates to the technical field of integrated circuit (IC: Integrated Circuit) electro-static discharge (ESD: Electro-Static Discharge) protection design in microelectronics and discloses a double-mode ESD protection I / O (Input / Output) circuit. The double-mode ESD protection I / O circuit is characterized in that a first-level protection circuit and a second-level protection circuit are collaboratively designed, an ESD high-current discharge path is provided, and meanwhile, comprehensive protection on a core circuit is realized through a bidirectional voltage clamp protection technology and protection on the ESD circuit is realized through a current limiting protection technology. The double-mode electro-static discharge protection I / O circuit of the invention can provide a targeted discharge path and targeted protection respectively for the two different discharge patterns: human body model discharge and electron gun model discharge.

Description

technical field [0001] The invention relates to a dual-mode electrostatic discharge protection I / O circuit, which is suitable for the design of electrostatic discharge protection of integrated circuits, and is especially suitable for the dual-mode electrostatic discharge protection design of a human body discharge model and an electron gun discharge model. Background technique [0002] As the level of integrated circuit manufacturing technology has entered the deep submicron era and nanometer era, the MOS transistors in the integrated circuit all adopt the lightly doped structure LDD (Lightly Doped Drain); the silicide is covered on the diffusion area of ​​the MOS transistor; the polycrystalline compound process It is used to reduce the series resistance of the gate polysilicon; and the thickness of the gate oxide layer of the MOS transistor is getting thinner and the channel length is getting smaller and smaller. These improvements have improved the integration of the chip,...

AI Technical Summary

Problems solved by technology

Therefore, the NMOS and PMOS directly connected to the I / O PAD in the core circuit are very prone to electrostatic discharge damage

When the ESD current flows through these devices, these devices are equivalent to a certain on-resistance, so a certain voltage difference will be formed along the ESD path, if the voltage difference between two nodes exceeds the breakdown of the devices connected to the nodes voltage, will cause breakdown failure

For example, in the nanometer process, the breakdown voltage of the core device may be lower than 10V. If the voltage difference formed by the ESD current at both ends of the core device exceeds 10V, it will cause the device to fail due to electrostatic breakdown.

[0005] Due to the large difference in the discharge current of the HBM and E-Gun models, taking the minimum protection requirement of 2000V electrostatic level in the industry as an example, the discharge current of the HBM model is about 1.33A, while the discharge current of the E-Gun model is about 6.5A, which also flows through a When turning on a device with a resistance of 2ohm, under HBM, the generated voltage difference is about 2.7V, which is far lower than the breakdown voltage of the device. The core circuit is relatively safe, but under the E-Gun model, the generated voltage difference is about 13V, which is already If the breakdown voltage of some devices is exceeded, the device will be broken down, and the circuit will fail in ESD

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