By combining advanced imaging schemes, innovative resist materials and optimized settings on ASML’s NXE:3400B system in imec’s cleanroom, the system is capable of printing lines/spaces at 24 nm pitch in a single exposure step. This imaging performance enables imec’s ecosystem of resist and patterning partners to use the NXE:3400B as a platform for early material development for future process nodes that will be enabled by ASML’s next-gen EUV system, which will first ship in 2022. The EXE:5000 will have a numerical aperture of 0.55, much higher than the 0.33 of current EUV systems like NXE:3400B.
The NXE:3400B allows illumination of the mask under high incident angles. Under standard illumination the EUV mask tends to distort the wafer image under these high incident angles – creating poor resist profiles. Through a fundamental understanding of EUV mask effects, obtained from a joint imec/ASML study, the teams have found an innovative way to compensate for unwanted image distortion. In combination with an illumination optimization, this enabled the teams to print a pitch as small as 24 nm in a single EUV exposure step with a minimum exposure dose of 34J/cm2. ASML’s NXE:3400B was installed in imec’s 300mm cleanroom in Q2 2019. It is now an important part of imec’s R&D activities.