KrF resists and process for implant layers at advanced nodes

The minimum design rule of device patterns for LSI implant layers has been shrinking constantly according to the industry requirements. Wavelength has been shortened and numerical aperture (NA) of the scanner has been enlarged to catch up with the required shrinkage. Implant layers are unique because the resist is nearly always used without an antireflective coating, and as a result, the resist is in direct contact with a multitude of substrate materials. In implant applications, the wafer topography sacrifices some of the lithographic performance in order to obtain adequate features on both top and bottom of the topography. KrF lithography has applied to most of the ion implant levels at today's advanced nodes. To solve the several issues in ion implant process, New KrF resist was designed specifically for the lithographic / implantation process requirements.