Resist materials for transition to green processing in semiconductor industry

Project Information

RESIN GREEN

Grant agreement ID: 101135783

DOI

10.3030/101135783

EC signature date 25 October 2023

Start date 1 January 2024

End date 30 June 2027

Funded under

• Digital, Industry and Space

Total cost

€ 3 777 574,50

EU contribution

€ 3 777 574,50

Coordinated by

"NATIONAL CENTER FOR SCIENTIFIC RESEARCH ""DEMOKRITOS"""
Greece

Periodic Reporting for period 1 - RESIN GREEN (Resist materials for transition to green processing in semiconductor industry)

Reporting period: 2024-01-01 to 2025-06-30

Summary of the context and overall objectives of the project

The global semiconductor market, with a size of 527.88 billion dollars in 2021, is one of the most profitable and largest ones that influences several digital and emerging technologies such as automotive, computers, tablets, telecommunications, etc. Unfortunately, the semiconductor manufacturing process entails a lot of toxic materials and/or materials causing environmental deterioration.

RESIN GREEN aims to develop green and environmentally friendly materials with high efficiency for photolithography, one of the most critical steps in semiconductor manufacturing. It is expected that by the end of the project, we will have developed three green materials platforms with high sensitivity, low line edge roughness, and high resolution (TRL4). The aforementioned technologies can be exploited almost directly by the industry, taking into consideration that STMicroelectronics is already a partner in the consortium, and ASML has already expressed interest.

In this context, we will develop new resist materials to eliminate or drastically reduce the use of organic solvents and aqueous alkaline solutions currently used in the lithographic process at the semiconductor manufacturing industry. The lithographical process steps that demand the significant amounts of solvents are the spin coating solution of the photoresist as well as the development process. We target to replace the standard organic solvents used in spin coating and the highly alkaline TMAH solutions used in development primarily with water. Greener organic solvents and very dilute basic developers will only be considered, if necessary, for meeting high-performance requirements. We aim to investigate both bio-sourced materials and new synthetic polymer-based photoresist platforms suitable for exposure at 193 nm, 248 nm, I-line and EUV and achieve significant breakthroughs . In addition, e-beam lithography will be considered, especially for evaluating the high-resolution potential of the proposed resist materials.

Furthermore, RESIN GREEN aims to demonstrate performance towards industrial viability of the greener resist materials to be developed. In this context advanced metrology techniques based on AFM-SEM and AI models will be elaborated and extensively used. Finally, the expected green outcome from the use of the new resist platforms will be evaluated and quantified.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

To accomplish the RESIN GREEN main goals we develop and investigate new resist materials based on 3 main approaches:
1st Approach: Bio-sourced resists (starting TRL: 2 – ending TRL:4)
2nd Approach: Negative tone hybrid photoresist materials (starting TRL:1 – ending TRL:4)
3rd Approach: Positive tone thermoresponsive (co)polymers (starting TRL:1 – ending TRL:4)

In the case of 1st Approach we continued work started by 2 partners of the project (CEA and CNRS/UCBL) on chitosan-based resists and extended this work at a range of additional exposure wavelengths to the ones investigated before. We developed new formulations with appropriate photosensitizers and we succeeded to dramatically improving the resist sensitivity at 193nm. In addition we demonstrated improved of sensitivity at 248 nm, where depending on the process and the specific formulation both positive and negative tone resist materials have been developed. Finally we have already demonstrated printing 100nm lines (pitch 200nm) with chitosan based resist formulation using e-beam exposure.

In the 2nd and 3rd approach we started from scratch by synthesizing new polymers for novel resist platforms, which are either hybrid organic/inorganic materials (2nd approach) or copolymers (3rd approach). In this case the polymers are not obtained from bio-sources but we again targeted to environmentally friendly processing characteristics as mentioned above. Resist materials based on these 2 approaches were first evaluated in UV lithography.

In the metrological part of the project the work carried out so far was devoted to the definition of a protocol for performing resist pattern metrology which is a prerequisite for the successful implementation of the next metrological tasks concerning SEM and AFM-based measurements of dimensional and roughness metrics of line/space and hole patterns. Also, NanoLER software was validated using actual SEM images of high-resolution photoresist materials patterns (line/space and contact holes) acquired following the defined metrology protocol.

Concerning Machine Learning metrological aspects, a comprehensive survey of related literature has been conducted combined with an update and re-implementation of existing software for SEM denoising and generation of synthetic data. Also, a new high-performance computing server was acquired to support ML applications while a novel hybrid AI-based Proportional-Integral-Derivative controller was developed at the PTB to improve the quality, speed, and accuracy of AFM measurements.

Design and planning of the first outgassing experiments involving green photoresist materials was initiated.

A first evaluation of the environmental benefits related to the use of bio-sourced resists has been accomplished.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The use of bio-sourced resists based on chitosan was successfully extended in new wavelength ranges. Improved lithographic performance was demonstrated beyond the state of the art.

New polymers were synthesized for both positive and negative tone resists processable in water or organic friendly solvents. These polymers were used as basic components of photoresist formulations and promising lithographic patterning was demonstrated.

New water soluble and/or water dispersible photoacid generators were synthesized and successfully incorporated in both bio-sourced resist formulations based on chitosan and also on novel resist formulations based on newly synthesized polymers. Among them PFAS free, newly synthesized PAGs were synthesized and successfully tested in resist formulations.

A novel kind of AFM scanner was developed hybridizing three different kinds of nano-positioning techniques: a 3-axes monocrystalline piezo stage, a 6-axes polycrystalline piezo stage and a 6-axes large-stroke magnetic levitation (MagLev) stage. All stages (MagLev and piezo stages) move sample and/or tip in parallel under real-time servo control in a coordinated manner, thus realizing long-stroke, high-speed and highly accurate AFM scanning.