Mr. Ashish Rathore Profile

Ashish Rathore

at imec

SPIE Involvement:

Author

Publications (7)

Proceedings Article | 31 October 2022 Poster

SCREEN's DT-3000 track-booster system: how can hardware improve EUV performance?

Andreia Santos, Yuji Tanaka, Masaya Asai, Masahiko Harumoto, Wesley Zanders, Jelle Vandereyken, Lander Verstraete, Ashish Rathore, Hyo Seon Suh

Proceedings Volume PC12292, PC122920W (2022) https://doi.org/10.1117/12.2643150

KEYWORDS: Extreme ultraviolet, Lithography, Line width roughness, Extreme ultraviolet lithography, Semiconducting wafers, Optical lithography, Ecosystems

Proceedings Article | 7 June 2022 Presentation

Exploring the synergy between EUV lithography and directed self-assembly

Hyo Seon Suh, Lander Verstraete, Julie Van Bel, Philippe Bézard, Geert Mannaert, Jae Uk Lee, Shouhua Wang, Ivan Pollentier, Ashish Rathore

Proceedings Volume PC12054, PC1205402 (2022) https://doi.org/10.1117/12.2622565

KEYWORDS: Directed self assembly, Extreme ultraviolet lithography, Optical lithography, Extreme ultraviolet, Semiconductors, Semiconducting wafers, Lithography, Light-matter interactions

Read Abstract +

Proceedings Article | 25 May 2022 Presentation + Paper

Improved resolution with main chain scission resists for EUV lithography

Akihide Shirotori, Manabu Hoshino, Ashish Rathore, SinFu Yeh , Danilo De Simone, Geert Vandenberghe, Hirokazu Matsumoto

Proceedings Volume 12055, 120550E (2022) https://doi.org/10.1117/12.2613445

KEYWORDS: Extreme ultraviolet lithography, Polymers, Lithography, Extreme ultraviolet, Electron beam lithography, Etching, Photoresist processing, Optical lithography, Photoresist materials, Photomasks

Read Abstract +

Proceedings Article | 25 May 2022 Presentation + Paper

To bake or not to bake... : the impact of prebake in the EUV resist process

Ivan Pollentier, Ashish Rathore, Mihir Gupta, Danilo De Simone, Hyo Seon Suh

Proceedings Volume 12055, 1205507 (2022) https://doi.org/10.1117/12.2616094

KEYWORDS: Extreme ultraviolet lithography, Extreme ultraviolet, Photo decomposable quencher, Chemistry, Silicon, Photoresist processing, Photoresist materials

Read Abstract +

In photoresist processing a prebake is traditionally used after coating the photoresist on a wafer to drive off solvents in the resist, resulting in a more stable film. In comparison to other stages of the lithography process (e.g. the conditions of exposure and post-exposure events), limited attention is paid in the prebake optimization for the EUV application. In this work, investigation is done to clarify its role for the case of chemically amplified resists (CAR). Compared to the earlier DUV application, this resist is used at significantly smaller thicknesses and has a significantly different composition in terms of photo acid generator (PAG) and quencher types and concentration. In a first screening, a commercial CAR material – coated on Si – was investigated towards contrast changes at different prebake temperatures. It was found that lower temperature can result in adhesion failure when substrate conditions are not optimized for adhesion. With proper adhesion promotion however, it was found that prebake temperature could be lowered significantly or even omitted, without clear change in contrast. Using model resists in combination with residual gas analysis (RGA), it was found that the use of photo-decomposable quencher could be responsible for maintaining contrast to lower bake temperatures. In a second investigation, an assessment towards outgas risk was done when using resists at lower prebake temperatures in EUV scanner environment. Finally, the printability of commercial CAR was tested on the NXE3400 EUV scanner at different prebake temperatures. This was done by coating the CAR on two available underlayer materials: spin-on-glass and deposited underlayer. Results show that the prebake temperature could be reduced or even omitted without a clear deterioration in process window, line edge roughness and defectivity. It was found that proper choice of underlayer material could even improve slightly the printing performance at lower prebake condition.

SPIE Journal Paper | 14 July 2021

Feasibility of unzipping polymer polyphthalaldehyde for extreme ultraviolet lithography

Ashish Rathore, Ivan Pollentier, Sunkuru S. Kumar, Danilo De Simone, Stefan De Gendt

JM3, Vol. 20, Issue 03, 034602, (July 2021) https://doi.org/10.1117/12.10.1117/1.JMM.20.3.034602

KEYWORDS: Extreme ultraviolet lithography, Polymers, Extreme ultraviolet, Chemical analysis, FT-IR spectroscopy, Photoresist materials, Spectroscopy, Semiconducting wafers, Photoresist developing, Optical lithography

Read Abstract +

Proceedings Article | 26 September 2019 Presentation + Paper

Development of main chain scission type photoresists for EUV lithography

A. Shirotori, Y. Vesters, M. Hoshino, A. Rathore, D. De Simone, G. Vandenberghe, H. Matsumoto

Proceedings Volume 11147, 111470J (2019) https://doi.org/10.1117/12.2536348

KEYWORDS: Extreme ultraviolet lithography, Polymers, Lithography, Photoresist materials, Photoresist developing, Extreme ultraviolet, Electron beam lithography, Line width roughness, Semiconducting wafers, Line edge roughness

Read Abstract +

Proceedings Article | 19 March 2018 Presentation + Paper

Unraveling the role of photons and electrons upon their chemical interaction with photoresist during EUV exposure

Ivan Pollentier, Yannick Vesters, John Petersen, Pieter Vanelderen, Ashish Rathore, Danilo de Simone, Geert Vandenberghe

Proceedings Volume 10586, 105860C (2018) https://doi.org/10.1117/12.2299593

KEYWORDS: Polymers, Electrons, Extreme ultraviolet lithography, Photons, Extreme ultraviolet, Chemistry, Polymerization, Chemical analysis, Photoresist materials, Chemical reactions

Read Abstract +

The interaction of 91.6 eV EUV photons with photoresist – in particular chemically amplified resist (CAR) – is different than exposure at 193 nm and 248 nm wavelengths. The latter is understood well and it is known that photons interact with electrons in the resist’s molecular valence orbitals (for chemically amplified resist (CAR) the photon interacts with the photo acid generator (PAG), which leads to a deprotection reaction on a polymer after a thermal catalytic reaction during a post-exposure-bake.). At EUV however, more steps are involved in the radiolysis process between the absorption of the photon and the final chemical modification. These are related to the generation of primary electrons and their decay to lower energy secondary electrons, and most of this steps are not well understood. In this paper, the reaction products from EUV and low energy electron exposure are examined using Residual Gas Analysis (RGA), which measures and analyzes the outgassing products related to the ongoing reactions. This investigation is applied firstly on a model CAR where details of the resist chemical constituents were known prior to testing. The measurement not only resolved information on the expected acid related reactions from the PAG and protection groups, but also exhibited direct scission reactions of the polymer, where some of them lead to polymerization reactions. Moreover, the measurement quantifies the balance between the different ongoing reactions, which were confirmed by contrast curve measurements. Based on learnings on the model resist, applied the measurement technique to commercial resists, where actual resist chemistry composition is not known. Despite that, it was found that information could be deduced to distinguish between acid related ongoing reactions and direct scission of reaction on the base polymer and quantify their relation. Moreover, different generations of commercial resists based on similar chemistry platform were investigated, which revealed that improvements in printing performance could be explained by PAG reaction yield increase.

Showing 5 of 7 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years