Stochastic Effects from Photon Distribution Entropy in High-k1 EUV Lithography

Stochastic Effects from Photon Distribution Entropy in High-k1 EUV Lithography
by Fred Chen on 08-04-2021 at 10:00 am

Stochastic Effects from Photon Distribution Entropy in High k1 EUV Lithography

Recent advances in EUV lithography have largely focused on “low-k1” imaging, i.e., features with pitches less than the wavelength divided by the numerical aperture (k1<0.5). With a nominal wavelength of 13.5 nm and a numerical aperture of 0.33, this means sub-40 nm pitches. It is naturally expected that larger… Read More


Stochastic Origins of EUV Feature Edge Roughness

Stochastic Origins of EUV Feature Edge Roughness
by Fred Chen on 07-11-2021 at 10:00 am

Stochastic Origins of EUV Feature Edge Roughness

Due to the higher energy of EUV (13.3-13.7 nm wavelength) compared to ArF (193 nm wavelength) light, images produced by EUV are more susceptible to photon shot noise.

Figure 1. (Left) 40 nm dense (half-pitch) line image projected onto wafer at 35 mJ/cm2; (Right) 20 nm dense (half-pitch) line image projected onto wafer at 70 mJ/cm2.Read More


SPIE 2021 – ASML DUV and EUV Updates

SPIE 2021 – ASML DUV and EUV Updates
by Scotten Jones on 03-17-2021 at 10:00 am

SPIE DUV 2021 ASML NXT4 DryWet Presentation final noWPD2 Page 42

At the SPIE Advanced Lithography Conference held in February, ASML presented the latest information on their Deep Ultraviolet (DUV) and Extreme Ultraviolet (EUV) exposure systems. I recently got to interview Mike Lercel of ASML to discuss the presentations.

DUV

Despite all the attention EUV is getting, most layers are still… Read More


How Line Cuts Became Necessarily Separate Steps in Lithography

How Line Cuts Became Necessarily Separate Steps in Lithography
by Fred Chen on 12-08-2020 at 10:00 am

How Line Cuts Became Necessarily Separate Steps in Lithography

Pretty much all the semiconductor nodes in the last two decades have had at least one layer where the minimum pitch pushes the limitation of the state-of-the-art lithography tool, with a k1 factor < 0.5, i.e., the half-pitch is less than 0.5*wavelength/numerical aperture. A number of published reports [1-4] have touched upon… Read More


Impact of Defocus and Illumination on Imaging of Pitch

Impact of Defocus and Illumination on Imaging of Pitch
by Fred Chen on 10-26-2020 at 10:00 am

Impact of Defocus

In an earlier article [1], the resolution limit for the space between paired features was described by the Rayleigh criterion of ~0.6 wavelength/numerical aperture, where the numerical aperture (NA) represented the sine of the largest angle for a ray focused from the lens to a point. It is also given by the radius of the lens divided… Read More


Lithography Resolution Limits – Arrayed Features

Lithography Resolution Limits – Arrayed Features
by Fred Chen on 04-17-2020 at 6:00 am

Lithography Resolution Limits Arrayed Features

State-of-the-art chips will always include some portions which are memory arrays, which also happen to be the densest portions of the chip. Arrayed features are the main targets for lithography evaluation, as the feature pitch is well-defined, and is directly linked to the cost scaling (more features per wafer) from generation… Read More


A Forbidden Pitch Combination at Advanced Lithography Nodes

A Forbidden Pitch Combination at Advanced Lithography Nodes
by Fred Chen on 03-06-2020 at 10:00 am

A Forbidden Pitch Combination at Advanced Lithography Nodes

The current leading edge of advanced lithography nodes (e.g., “7nm” or “1Z nm”) features pitches (center-center distances between lines) in the range of 30-40 nm. Whether EUV (13.5 nm wavelength) or ArF (193 nm wavelength) lithography is used, one thing for certain is that the minimum imaged pitch … Read More


EUV is NOT Ready for 7nm!

EUV is NOT Ready for 7nm!
by Daniel Nenni on 02-27-2017 at 8:00 am

The annual SPIE Advanced Lithography Conference kicked off last night with vendor sponsored networking events and such. SPIE is the international society for optics and photonics but this year SPIE Advanced Lithography is all about the highly anticipated EUV technology. Scotten Jones and I are at SPIE so expect more detailedRead More