Nanopatterning is the core of semiconductor technology as it drives the downscaling below the 7 nm node, enabling higher speed, density of transistors and computing performance. In addition, nanofabricated three-dimensional patterned structures are used in devices for photonics, biotechnology and other forms of nanotechnology.[1] In the early 2000s, the 193nm immersion lithography enabled 45nm node patterning. From then, for scaling, either light source (from 193nm to Ar-F) or integration routes (multiple patterning) have been developed. For beyond the 10nm node, extreme ultraviolet lithography (EUVL) with a light source of 13.5 nm, can be applied. , Associated with nano-patterning, there is a long list of challenges: (i) EUVL photoresists (PR) and mask infrastructure and control of the created nanoscale patterns; (ii) low throughput and process cost; (iii) environmental footprint as it is based on litho-etch subtractive processes; (iv) high complexity thus decreasing fabrication reliability; (v) overlay errors and defectivity. Therefore, innovative solutions are required. Area selective deposition (ASD) offers the potential to relax downstream processing steps by enabling self-aligned processes and bottom-up lithography. The main goal of this MSCA proposal Area-selective Deposition-enabled ultiMAte extensIon of lithogRaphy (ADMAIR) is to overcome the potentially show-stopping challenges associated with EUV lithography and EUV materials at the sub-10nm scale by depositing additive bottom-up materials.
As planned, the project duration was 24 months but within this period, ADMAIR has not been able to address fully all the scientific objectives. In resolution, alternative approaches have been investigated, opening promising perspectives for future application domains. The project did benefit from interdisciplinary joint development projects involving material suppliers and lithography stakeholders, which is a unique advantage of IMEC and offered valuable professional development and training opportunities for the MSCA candidate.
The details of those approaches will be descripted in the part B of the report. The initial WP are presented below.
Work Package 1 (WP1): Surface treatments and ASD on blankets and patterned
Work Package 2 (WP2): Surface characterization methodologies
Work Package 3 (WP3): Development of defect removal strategies
Work Package 4 (WP4): Application oriented demonstrators
A new project plan focusing on the three applications described above was worked out and executed and is presented in the table 1. The different applications identified have been defined as individual work packages.
• Approach 1: Hard Mask ASD lithography
• Approach 2: Add a passivation step to get a nucleation delay
• Approach 3: Tone inversion using hydrophobic sensitive materials
• Approach 4: Resist Hardening
