ADI : After Development Inspection ACI : After Cleaning Inspection FI : Final Inspection DI : Developing Inspection CD skew (CD bias) = ACI - ADI (삼성) = FI - DI (하이닉스) CD 측정 설비 : ILS(In-line SEM) (Hitachi SEM) 단면 관찰 설비 : Broken SEM (SK), VSEM (Samsung)