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

Abstract

In support of the Extreme Ultraviolet Lithography (EUVL) roadmap, a SEMATECH †/CNSE ‡ joint program is under way to develop 13.5 nm R&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 [POB]) is specified to less than 1 nm root mean square (RMS) over its 30 µm × 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 nm with a k-factor of 0.41 and a resolution of 8 nm with extreme dipole illumination. The POB's magnification (5X), track length, and mechanical interfaces match the currently installed 0.3 NA POBs [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].This manuscript discusses the on-going efforts to develop and fabricate this optical projection module.

Traceable Reference Full Metrology Chain for Innovative Aspheric and Freeform Optical Surfaces Accurate at the Nanometer Level

“…[ 1 , 2 , 3 , 4 ], metrology capabilities of aspheric and freeform surfaces must be aligned with advances made in the optical design domain [ 5 ]. The need for an accurate full metrology chain for asphere and freeform optics is not exclusively reserved to the extreme ultraviolet lithography (EUVL) [ 6 ], but it concerns also the synchrotron [ 7 , 8 ], astronomy [ 9 , 10 ], medical device [ 11 ], security and several other domains. The full metrology chain could include the development of robust reference mathematical least-squares (LS) and minimum zone (MZ) fitting algorithms, thermo-invariant material measures and ultra-high precision measuring machines ( Figure 1 ); the three components are necessary for building the traceable full metrology chain at NMIs (national metrology institutes) and DIs (Designated Institutes).…”

Modelling and simulation of mid-spatial-frequency error generation in CCOS

“…Ultra-precision optical elements have high machining accuracy, and play very important roles in advanced optical systems, such as, the large astronomical telescope, the extreme ultraviolet lithography and the high power laser device [1][2][3]. These optical systems have put forward the higher requirements (i.e., MSF errors, surface roughness, and surface defects) of optical elements than those in the traditional optical systems.…”

Distortion of removal function based on the local asphericity of aspheric surface and the viscoelasticity of polishing tool in computer-controlled optical surfacing

“…Therefore, it plays an important role in the projects such as high power laser engineering, large astronomical telescope project, and extreme ultraviolet lithography engineering. [1][2][3][4][5] In order to meet the requirements of high precision and mass production of aspheric element, a batch manufacturing process flow for large aspheric has been proposed, which includes ''ultra precision grinding and deterministic polishing''. Indeed, the precision grinding is utilized for shaping formation of the aspheric element firstly.…”