Tool and process optimization for 100-nm maskmaking using a 50-kV variable shaped e-beam system

An overview will be presented of high-resolution e-beam lithography equipment issues and processes used in the fabrication of photomasks/reticles needed for 100nm maskmaking. As reported and discussed repeatedly, the emerging advanced optical and next generation lithography for 100nm and beyond requires masks with a well controlled CD variation and high pattern placement accuracy. Our paper shows the possibility of 100nm patterning by using standard resist materials (e.g. ZEP 7000) or other advanced resist materials under optimized processing exposed with a 50keV shaped-beam vector-scan Leica SB350MW mask writer e-beam pattern generator. The presented results will show that this commercially available e-beam system together with built-in exposure optimization methods (proximity, local heating, fogging) meets the challenges of the 100nm device generation with extendibility to at least 70nm. Details of the exposure optimization possibilities, including a flexible determination method of proximity input parameters and resist-pattern transfer methods maintaining the required CD-control will be discussed also.