Electrostatic Discharge Protection For Advanced Nanoscale Integrated Circuits And Processes

In integrated circuit industry,Electrostatic Discharge(ESD)failures account for a large proportion of the total failure modes,causing a lot of economic losses For advanced nanoscale integrated circuit processes,the power supply voltage is low,thinner gate oxides lead to lower breakdown voltages.As a result,the ESD design window has become much narrower and the design for ESD protection has become more difficult.In this article,the research of ESD protection devices and full chip ESD protection in nanoscale processes are summarized as follows:(1)This paper makes a research of the traditional ESD protection devices commonly used in advanced nanoscale integrated circuit processes,which include diode,MOSFET and SCR.By adjusting the important parameters of the device,the working mechanism and physical mechanism of three traditional ESD protection devices are analyzed and summarized in combination with the 55 nm flow film results.And according to the characteristics of the device,a corresponding ESD full chip protection scheme is proposed.It provides a reference for future ESD protection.(2)In 21 nm CMOS processes,the design window of I/O port is determined to be 1.32V-3.7V and the design window of power port is 2.8V-7V.Further,based on the narrow design window,DCSCR,DTSCR and diode-chain are designed to complete full chip ESD protection.Firstly,this article changes the trigger voltage of the DCSCR in a stacking manner so that it can meet different design windows,and the two DCSCRstacked device meet the power port design window and can be used for power port protection;then this article also proposes an improved layout method to reduce the onresistance of DCSCR by 1.5?;finally,in order to make the DTSCR turning on easily,the P-well resistance of the DTSCR is increased so that it can be used for I/O port protection.(3)For some advanced bidirectional I/O ports,ESD protection devices are usually required to have dual-directional current conduction capacity.A novel RC-triggered bidirectional ESD protection circuit is proposed to meet the requirement.In this circuit,the improved bridge rectifier circuit is formed by diode rectifier circuit paralleling MOSFET rectifier circuit.The circuit can convert the input voltage in I/O port ranging between negative and positive values into a single polarity input voltage to the RCtriggered circuit and turn on the clamping device NMOS to discharge the ESD current.The novel circuit can provide efficient bidirectional ESD protection for the I/O port when the input voltage in I/O port ranging between negative and positive values by verifying through SPICE simulation software.