Advancing Semiconductor Processes with Novel Extreme UV Photoresist Materials

Advancing Semiconductor Processes with Novel Extreme UV Photoresist Materials
by Rupesh Yelhekar on 09-06-2023 at 10:00 am

Banner Advancing Semiconductor Processes with Novel Extreme UV Photoresist Materials

Introduction

The ever-growing demand for faster, smaller, and more efficient electronic devices has fueled the semiconductor industry’s relentless pursuit of innovation. One crucial technology at the heart of semiconductor manufacturing is Extreme Ultraviolet Lithography (EUVL) to achieve smaller feature sizes… Read More


Lithography Resolution Limits: The Point Spread Function

Lithography Resolution Limits: The Point Spread Function
by Fred Chen on 03-21-2023 at 6:00 am

Lithography Resolution Limits The Point Spread Function

The point spread function is the basic metric defining the resolution of an optical system [1]. A focused spot will have a diameter defined by the Airy disk [2], which is itself a part of the diffraction pattern, based on a Bessel function of the 1st kind and 1st order J1(x), with x being a normalized coordinate defined by pi*radius/(0.5… Read More


Multiple Monopole Exposures: The Correct Way to Tame Aberrations in EUV Lithography?

Multiple Monopole Exposures: The Correct Way to Tame Aberrations in EUV Lithography?
by Fred Chen on 02-01-2023 at 6:00 am

Multiple Monopole Exposures 1

For a leading-edge lithography technology, EUV (extreme ultraviolet) lithography is still plagued by some fundamental issues. While stochastically occurring defects probably have been the most often discussed, other issues, such as image shifts and fading [1-5], are an intrinsic part of using reflective EUV optics. However,… Read More


Secondary Electron Blur Randomness as the Origin of EUV Stochastic Defects

Secondary Electron Blur Randomness as the Origin of EUV Stochastic Defects
by Fred Chen on 01-09-2023 at 10:00 am

Secondary Electron Blur Randomness as the Origin of EUV Stochastic Defects

Stochastic defects in EUV lithography have been studied over the last few years. For years, the Poisson noise from the low photon density of EUV had been suspected [1,2]. EUV distinguishes itself from DUV lithography with secondary electrons functioning as intermediary agents in generating reactions in the resist. Therefore,… Read More


Electron Blur Impact in EUV Resist Films from Interface Reflection

Electron Blur Impact in EUV Resist Films from Interface Reflection
by Fred Chen on 11-08-2022 at 6:00 am

Electron Blur Impact in EUV Resist Films from Interface Reflection

The resolution of EUV lithography is commonly expected to benefit from the shorter wavelengths (13.2-13.8 nm) but in actuality the printing process needs to include Pde the consideration of the lower energy electrons released by the absorption of EUV photons. The EUV photon energy itself has a nominal energy range of 90-94 eV,… Read More


Where Are EUV Doses Headed?

Where Are EUV Doses Headed?
by Fred Chen on 10-11-2022 at 6:00 am

Where Are EUV Doses Headed 1

In spite of increasing usage of EUV lithography, stochastic defects have not gone away. What’s becoming clearer is that EUV doses must be managed to minimize the impact from such defects. The 2022 edition of the International Roadmap for Devices and Systems has updated its Lithography portion [1]. An upward trend with decreasing… Read More


EUV’s Pupil Fill and Resist Limitations at 3nm

EUV’s Pupil Fill and Resist Limitations at 3nm
by Fred Chen on 08-08-2022 at 10:00 am

EUV Pupil Fill and Resist Limitations at 3nm p1

The 3nm node is projected to feature around a 22 nm metal pitch [1,2]. This poses some new challenges for the use of EUV lithography. Some challenges are different for the 0.33NA vs. 0.55NA systems.

0.33 NA

For 0.33 NA systems, 22 nm pitch can only be supported by illumination filling 4% of the pupil, well below the 20% lower limit for

Read More

Demonstration of Dose-Driven Photoelectron Spread in EUV Resists

Demonstration of Dose-Driven Photoelectron Spread in EUV Resists
by Fred Chen on 05-08-2022 at 10:00 am

Demonstration of Dose Driven Photoelectron Spread in EUV Resists

As a consequence of having a ~13.5 nm wavelength, EUV photons transfer ~90% of their energy to ionized photoelectrons. Thus, EUV lithography is fundamentally mostly EUV photoelectron lithography. The actual resolution becomes dependent on photoelectron trajectories.

Photoelectron trajectories in EUV lithography were… Read More


Adding Random Secondary Electron Generation to Photon Shot Noise: Compounding EUV Stochastic Edge Roughness

Adding Random Secondary Electron Generation to Photon Shot Noise: Compounding EUV Stochastic Edge Roughness
by Fred Chen on 04-26-2022 at 6:00 am

Compounding EUV Stochastic Edge Roughness 2

The list of possible stochastic patterning issues for EUV lithography keeps growing longer: CD variation, edge roughness, placement error, defects [1]. The origins of stochastic behavior are now well-known. For a given EUV photon flux into the resist, a limited fraction are absorbed. Since the absorption is less than 5% affected… Read More


EUV Resist Absorption Impact on Stochastic Defects

EUV Resist Absorption Impact on Stochastic Defects
by Fred Chen on 04-03-2022 at 10:00 am

EUV Resist Absorption Impact on Stochastic Defects 1

Stochastic defects continue to draw attention in the area of EUV lithography. It is now widely recognized that stochastic issues not only come from photon shot noise due to low (absorbed) EUV photon density, but also the resist material and process factors [1-4].

It stands to reason that resist absorption of EUV light, which is … Read More