Study of device mass production capability of the character projection based electron beam direct writing process technology toward 14 nm node and beyond

Abstract. Techniques to appropriately control the key factors for a character projection (CP) based electron beam direct writing technology for mass production are shown and discussed. In order to achieve accurate CD control, the CP technique using the master CP is adopted. Another CP technique, the Packed CP, is used to obtain suitable shot count. For the alignment on the some critical layers which normally have an even surface, the process removing SiO2 material filled in the alignment marks is added and then the alignment marks can be detected using electron beam. The proximity effect correction using the simplified electron energy flux model and the hybrid exposure are used to obtain enough process margins. As a result, the sufficient CD accuracy, overlay accuracy, and yield are obtained on the 65 nm node device. Due to the proper system control, more than 10,000 production wafers have been successfully exposed so far without any major system downtime. It is shown that those techniques can be adapted to the 32 nm node production with slight modifications. It is expected that by using the Multi Column Cell exposure method, those techniques will be applicable to the rapid establishment for the 14 nm node technology.