.0.25 Micron Cmos Process, Multi-level Gate Oxide Integrity

Reliability problems of IC(integrated circuit) became much important in ULSI(ultra large scale integrated circuit) development. Reliability test and analysis can improve ULSI quality and reliability level, which can provide suggestion to IC designer & manufacturing for performance improvement, advice customer operation and maintenance method.Gate Oxide Integrity(GOI)plays an important role in IC 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.Original single gate process can' t meet current functional IC requirement, multiple gate oxide is more popular in mix signal and flash IC. Based on 0.25um CMOS process, there are multiple gate oxide thickness devices on one chip, and study the GOI failure for multiple gate oxide process specialty.The paper also discussed the silicon oxidation and GOI reliability. To improve the GOI, especially consider the charge' s influence to HF etching and illumination effect for charge release. Many experiments have done to find optimization illumination, which is a new way to improve multiple gate oxide GOI performance.The conclusion has been applied to 0.25um embedded flash IC production.