Vibration levels in MET5 exposures were reduced from 1.5 nm RMS to 0.8 nm RMS by tuning the vibration isolation system and removing non-compliant hardware. Frequency doubling exposures were improved by replacing the Fourier synthesis pupil scanner mirror. Focus-exposure-matrix outliers have been solved by patching a bug in the control software. 9 nm half-pitch lines and 8 nm half-pitch lines were printed in 11 nm thick MOx resist.
A 0.5-NA extreme ultraviolet micro-field exposure tool has been installed and commissioned at beamline 188.8.131.52 of the Advanced Light Source synchrotron facility at Lawrence Berkeley National Laboratory. Commissioning has demonstrated a patterning resolution of 13 nm half-pitch with annular 0.35 – 0.55 illumination; a patterning resolution of 8 nm half-pitch with annular 0.1 – 0.2 illumination; critical dimension (CD) uniformity of 0.7 nm 1σ on 16 nm nominal CD across 80% of the 200 um x 30 um aberration corrected field of view; aerial image vibration relative to the wafer of 0.75 nn RMS and focus control and focus stepping better than 15 nm.
The Berkeley MET5, funded by EUREKA, is a 0.5-NA EUV projection lithography tool located at the Advanced Light Source at Berkeley National Lab. Wavefront measurements of the MET5 optic have been performed using a custom in- situ lateral shearing interferometer suitable for high-NA interferometry. In this paper, we report on the most recent characterization of the MET5 optic demonstrating an RMS wavefront 0.31 nm, and discuss the specialized mask patterns, gratings, and illumination geometries that were employed to accommodate the many challenges associated with high-NA EUV interferometry.
The SEMATECH High Numerical Aperture Actinic Reticle Review Project (SHARP) is a synchrotron-based extreme ultraviolet (EUV) microscope dedicated to photomask research. SHARP has been operational and serving users since June, 2013, and in eight months, SHARP has recorded over 71,000 high-resolution images. Exposure times are 5 to 8 seconds, and 8 or more through-focus series can be collected per hour at positions spanning the entire mask surface. SHARP’s lossless coherence-control illuminator and variable numerical aperture (NA) enable researchers to emulate the imaging properties of both current and future EUV lithography tools. SHARP’s performance continues to improve over time due to tool learning and upgraded capabilities, described here. Within a centered, 3-μm square image region, we demonstrate an illumination power stability above 99%, and an average uniformity of 98.4%. Demonstrations of through-focus imaging with various illumination coherence settings highlight the capabilities of SHARP.
The SEMATECH High Numerical Aperture Actinic Reticle Review Project (SHARP) is a newly commissioned,
synchrotron-based extreme ultraviolet (EUV) microscope dedicated to photomask research. SHARP offers several major
advances including objective lenses with 4xNA values from 0.25 to 0.625, flexible, lossless coherence control through a
Fourier-synthesis illuminator, a rotating azimuthal plane of incidence up to ±25°, illumination central ray angles from 6 to 10°, and a continuously tunable, EUV illumination wavelength. SHARP is now being used to study programmed and
native mask defects, defect repairs, mask architecture, optical proximity correction, and the influence of mask substrate
roughness on imaging. SHARP has the ability to emulate a variety of current and future lithography tool numerical
apertures, and illumination properties. Here, we present various performance studies and examples where SHARP’s
unique capabilities are used in EUV mask research.
The SEMATECH High-NA Actinic Reticle review Project (SHARP) is a synchrotron-based, EUV-wavelength microscope, dedicated to photomask imaging, now being commissioned at Lawrence Berkeley National Laboratory. In terms of throughput, resolution, coherence control, stability and ease of use, SHARP represents a significant advance over its predecessor, the SEMATECH Berkeley Actinic Inspection Tool (AIT), which was decommissioned in September 2012. SHARP utilizes several advanced technologies to achieve its design goals: including the first Fouriersynthesis illuminator on a zoneplate microscope, EUV MEMS mirrors, and high-efficiency freestanding zoneplate lenses
with numerical aperture values up to 0.625 (4×). In its first week of operation, SHARP demonstrated approximately 150 times higher light throughput than AIT and a spatial resolution down to 55-nm half-pitch with 0.42 4×NA (i.e. the smallest feature size on our test mask.) This paper describes the current status of the tool commissioning and the performance metrics available at this early stage.