Abstract
Techniques to introduce of electron beam direct writing (EBDW) technology into the volume production lines for the 65
nm process technology are shown and discussed. In order to apply these techniques in a harmonious way, partial
modifications to the current production line infrastructures are required, because those infrastructures have been
optimized for the conventional photolithography technology. One of the large differences is with the alignment. For the
gate layer, the appropriate solution is to have an additional process step to remove SiO2 material filled in the shallow
trench isolation alignment marks before the patterning. For the dual damascene process at the metal layers, careful
consideration of the choice between the indirect alignment or the direct alignment is necessary, when the metal layer is
aligned to the previous via layer underneath. We expect that these techniques can be used for the advanced node devices
as well, while some new structures would be applied on these devices. In addition to the optimizing the alignment mark
structures, the appropriate adjustment of EBDW system parameters by advanced process control (APC) is required, in
order to have enough overlay accuracy at the actual production use. Although such process control systems are normally
optimized to photolithography, we have confirmed that APC system can be also used for the EBDW technology for
appropriate overlay accuracy control. Furthermore, the alignment budget in our systems is created and the alignment
accuracy in our future system is estimated based on it. Based on the findings from these discussions, we expect that the EBDW with e-beam-only alignment will be applicable for the production of the 11 nm half-pitch process technology node and the beyond.
