Repeating Defect Analysis And Solution For Semiconductor Manufactory Litho Process

At21st century, according to china semiconductor company,65nm technology hadbeen passed,45/40nm technology also are released at china semiconductor company,32/28nm technology productor had completed developement now. So chinasemiconductor company must shortened the gap between the world advancedsemiconductor company, in order to keep the company development, the key factorare that develope the advanced technology, keep the line yield and gain the revenue.Because chip CD narrow down, semiconductor litho process has to faced morechallenge since it is the most important process in semiconductor manufactory.During regular operation, litho repeating defect is the first yield killer, and inducedwafer yield loss, even caused wafer scrap. It is the line excursion and will impactsemiconductor compay revenue. Particle contamination, mask HAZE, ESD damage,mask scratch, scanner exposure unit contamination are the key index of litho repeatingdefect.This paper introduced the basic theory of litho process, including resist coating,exposure, developer, Overlay and Critical Demetion inline check. Then introducedmask and basic photomask manufacturing process, introduced the relationshipbetween mask and litho repeating defect.This paper analyzed the real litho repeating defect case that happened duringsemiconductor manufactory, described4litho repeating defect case, troubleshooting method, finding and conclusion.In-line wafer inspectin and mask offline inspection is the most effective tools forLitho repeating defect reduction, in world wild semiconductor manufactory, brightand dark filed inspection sytem are used for wafer inspection, UV inspection systemand IRIS scan are used for mask inspection.At last chapter, this paper provided the total solution about litho repeating defectreduction according to the experience, include mask storage environmentimprovement, HAZE issue improvement, lithi area particle improvement, scannerexposure process particle control, litho area ESD control, mask clean control andimprovement, mask inline monitor methold optimize, all these effect can reduce thecase happening ratio of litho repeating defect...