Grid Block The Reoxidation Of Eeprom Threshold Voltage And The Influence Of A Controlled Study

In modern IC fabrication, In order to get different kind of VT, We choose to twice deposition oxide on Silicon wafer or pre-injection before oxidation thus lead to different kind of oxidation deposition rate. Then we got two kind of MOS transisters, the HVMOS has thick gate oxide and the LVMOS has thin gate oxide。Gate Oxide plays an important role in IC(INTEGRATED IRCUITS)industry. Gate Oxide failure will directly impact all kind of MOS characteristics, such as threshold voltage, breakdown voltage, etc. Besides, it is also directly related with IC yield and reliability, but nowadays GOI inline monitor and inline thickness has become less useless while monitoring the gate-oxide quality which grown up with DCE gas, Count by a product average run cycle time, if you fail in monitoring the gate-oxide quality, it will became a disaster for our FAB that countless money will be lost due to mass production scrap.This Thesis is based on one case occurred in SMIC in Shang hai,8ch FAB, that gate oxide growing with DCE gas lead to different kind of VT, which lead to product low yield. We choose different gas flow,DCE,etc,to study the relation between them, analyzing Vfb,Qtot,Qm,Vs,SPV, and doing experiment by repeating test thus get the same result.It can be concluded that the small flux of DCE has positive influence to the device,but the lower flux of DCE has little impact to the inline thickness;but large affect to the characters of the VT performance, Qtot of Dual Gate oxide is as one monitor item to this process and is a good complementarity to the real time gate oxide monitoring,real time monitoring is strengthened,and Further more, Qtot is as one good way to align the transiter characters of different fab,or for tool expansion.Considering mass production and the quality of production,the meaning of this monitor is far-reaching by the way of real time monitoring.