Influence of Incident Angle Change Caused by Different Off-Axis Illumination on 16 nm Node Extreme Ultraviolet Lithography - (PPT)

摘要

Currently, 6 degree oblique incidence is main stream, but 5 degree incident angle is also studied for 0.25 NA in EUVL. Incident angles larger than 6 degree are also considered for larger NA. This incident angle will affect many things, eventually to the line width. The shadow effect in the EUVL mask is an important factor that decreases the contrast of the aerial image and causes a directional problem, thus it will make line width variation. The off-axis illumination (OAI) will be used with conventional on-axis illumination to make much smaller patterns. This OAI will split the main beam and change the incident angle. We focused on influence of incident angle change due to illumination type for the 22 nm & 16 nm node line and space (L/S) patterns. We checked the influence of incident angel variation caused by different pole position of various illuminations. And, the influence of OAI was studied by checking horizontal-vertical (H-V) CD difference.