Fast mask CD uniformity measurement using zero order diffraction from memory array pattern

CD Uniformity (CDU) control is getting more concerning in lithographic process and required to control tighter as design rule shrinkage. Traditionally CDU is measured through discrete spatial sampling based data and interpolated data map represents uniformity trends within shot and wafer. There is growing requirement on more high sampling resolution for the CDU mapping from wafer. However, it requires huge time consumption for CD measurements with traditional methods like CD-SEM and OCD. To overcome the throughput limitation, there was an approach with inspection tool to measure CD trends on array area which showed good correlation to the traditional CD measurement. In this paper, we suggest a fast mask CD error estimation method using 0 th order of diffraction. To accomplish fast measurement, simple macro inspection tool was adopted to cover full wafer area and scan result gives good correlation with mask uniformity data.