Periodic Reporting for period 1 - ADMAIR (Area-selective Deposition-enabled ultiMAte extensIon of lithogRaphy)
Reporting period: 2020-06-01 to 2022-05-31
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
Approach 1: no relevant results but very elegant and innovative approach. Need to work in close collaboration with material suppliers
Approach 2: interesting results are demonstrated
- NF3 plasma allows to graft F bonds at the PR surface
- F-bonds block the HM growth around 100 cycles
- Material is still sensitive at EUV exposure even if sensitivity is degraded
- Necessary to find the best compromise between passivation efficiency and PR sensitivity
Approach 3: few interesting observations have been done but necessary to work in close collaboration with material suppliers to achieve the ASD process
- Nucleation delay is found on exposed area as expected
- However, Ti diffusion is detected which is bad for etch contrast
- Higher exposure dose allows to reduce Ti diffusion mechanisms, but nucleation delay is reduced
- Need to develop new material with higher density to avoid the Ti diffusion
Approach 4: good preliminary results
- DMA-TMS treatment block HM growth on Si based surfaces. No impact for growth on PR.
- Selectivity is degraded for blanket unexposed samples.
- Need to tune exposure dose and PEB T to get an efficiency rinse. Mandate to reach the Si surface and have TMS grafting good enough.
- More promising results / need to progress
- To be able to block HM material nucleation on non-growth area, WCA value needs to be above 100° and the polar part as low as possible
- The density of the PR/UL needs to be high enough in order to avoid precursor diffusion (in case of ALD precursor has a small size) and etch contrast degradation
- Add a passivation step can help to block HM nucleation but the PR/UL sensitivity is reduced and so selectivity window can be too short