Projection optics for extreme ultraviolet lithography (EUVL) micro-field exposure tools (METs) with a numerical aperture of 0.5

In support of the Extreme Ultraviolet Lithography (EUVL) roadmap, a SEMATECH/CNSE joint program is under way to develop 13.5 mn R and D photolithography tools with small fields (micro-field exposure tools [METs]) and numerical apertures (NAs) of 0.5. The transmitted wavefront error of the two-mirror optical projection module (projection optics box [FOB]) is specified to less than 1 mn root mean square (RMS) over its 30 μm x 200 μm image field. Not accounting for scatter and flare losses, its Strehl ratio computes to 82%. Previously reported lithography modeling on this system [1] predicted a resolution of 11 mn with a k-factor of 0.41 and a resolution of 8 mn with extreme dipole illumination. The FOB's magnification (5X), track length, and mechanical interfaces match the currently installed 0.3 NA FOBs [2] [3] [6], so that significant changes to the current tool platforms and other adjacent modules will not be necessary. The distance between the reticle stage and the secondary mirror had to be significantly increased to make space available for the upgraded 0.5 NA illumination modules [1].

[1]  Louis Andrew Marchetti.  Fabrication and metrology of 10X Schwarschild optics for EUV imaging , 2004, SPIE Optics + Photonics.

[2]  Kim Dean,et al.  The EUV resist test center at SEMATECH-North , 2006, SPIE Advanced Lithography.

[3]  G.E. Moore,et al.  Cramming More Components Onto Integrated Circuits , 1998, Proceedings of the IEEE.

[4]  M. Booth,et al.  High-resolution EUV imaging tools for resist exposure and aerial image monitoring , 2005, SPIE Advanced Lithography.

[5]  Dominic Ashworth,et al.  The SEMATECH Berkeley MET: demonstration of 15-nm half-pitch in chemically amplified EUV resist and sensitivity of EUV resists at 6.x-nm , 2012, Advanced Lithography.

[6]  Lisa R. Rich,et al.  Contamination and degradation of 157-nm stepper optical components: field experience at International SEMATECH , 2002, SPIE Advanced Lithography.

[7]  K. Freischlad.  Absolute interferometric testing based on reconstruction of rotational shear. , 2001, Applied optics.

[8]  Malcolm C. Gower,et al.  High-resolution EUV microstepper tool for resist testing and technology evaluation , 2004, SPIE Advanced Lithography.

[9]  Kenneth A. Goldberg,et al.  Recent results from the Berkeley 0.3-NA EUV microfield exposure tool , 2007, SPIE Advanced Lithography.

[10]  Regina Soufli,et al.  Sub-diffraction-limited multilayer coatings for the 0.3 numerical aperture micro-exposure tool for extreme ultraviolet lithography. , 2007, Applied optics.

[11]  Kenneth A. Goldberg,et al.  Status of EUV micro-exposure capabilities at the ALS using the 0.3-NA MET optic , 2004, SPIE Advanced Lithography.

[12]  Emil C. Piscani,et al.  Demonstration of sub-45-nm features using azimuthal polarization on a 1.30NA immersion microstepper , 2007, SPIE Advanced Lithography.

[13]  Guenther Seitz,et al.  Mirror substrates for EUV lithography: progress in metrology and optical fabrication technology , 2000, SPIE Optics + Photonics.

[14]  Russell M. Hudyma,et al.  High-NA Camera for an EUVL Microstepper , 2000 .

[15]  P. Naulleau,et al.  Extreme-ultraviolet microexposure tool at 0.5 NA for sub-16 nm lithography. , 2008, Optics letters.

[16]  C. Evans,et al.  Test optics error removal. , 1996, Applied optics.

[17]  Steven M. Arnold,et al.  Verification and certification of CGH aspheric nulls , 1995, Optics & Photonics.