Implant patterning

摘要

After comparing the available technologies for patterning implants, it is clear that the engineer has choices in developing a process. A dyed photoresist covers existing topography well and thus provides adequate CD control. In contrast, due to its light-absorbing nature, a dyed photoresist can have sloping sidewalls, which reduce the control of the implant area. A photoresist with a TARC is a bilayer stack and thus requires two coating steps. The TARC can be applied to an existing process, but because the TARC is on the top of the litho stack, it cannot completely control reflectivity, has no effect on reflective notching, and provides less than optimum CD control. A developable BARC plus a photoresist provides the best CD control and therefore the best process. This process must first be optimized, as improper processing can result in undercutting, footing, or post-develop residue. This wet-developable BARC technology mitigates implant-patterning problems and meets predetermined product specifications.