Component optimisation in the multi-trigger resist

Popescu, Carmen; O'Callaghan, Greg; McClelland, Alexander; Roth, John R.; Jackson, Ed; Robinson, Alex P. G.

doi:10.1117/12.2614217

Cited by 4 publications

(6 citation statements)

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“…The MTR material is not generally compatible with spin-on-glass (SOG) underlayers, and whilst performance can be improved with customised SOG processing, the organic Brewer Scientific OptistackAL412 underlayer [19] was found to give the best performance of a commercial underlayer. The search for the optimum underlayer, which provides good compatibility with the MTR resist and renders equal or better lithographic performance to AL412 continues.…”

Section: Underlayer Optimisationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[16] In particular, we showed that good lithographic performance for P28 L/S with doses below 20 mJ/cm 2 and P36 and P34 hexagonal pillars with doses below 30 mJ/cm 2 . [19,20] More recently we have explored three separate routes to significantly improve the Z-factor of the MTR system, either by increasing the activation rate of the monomer activation (Gen2.1); adjusting the relative reaction rates of the initiation and propagation rates of the ROP (Gen2.2); and via a more efficient multi-trigger quenching mechanism (Gen2.3). Here we present more detailed information on the Gen2.1 approach, together with initial results for Gen2.3, and first indications that the advantages gained by each approach are not correlated, and thus can be combined for further improvements of the MTR Z-factor (Gen2.5).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

EUV lithography patterning using multi-trigger resist

Popescu¹,

O'Callaghan²,

McClelland³

et al. 2023

Advances in Patterning Materials and Processes XL

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Research and development of EUV photoresists capable of supporting future requirements such as high-NA EUV continues. It is foreseen that, to contend with much higher photon-shot noise, resists will require high EUV absorbance to offset the need for thin films in high-NA, where depth of focus may be less than 20nm. We are developing a photoresist based on the multi-trigger concept, which seeks to suppress roughness using a new photoresist mechanism, and which is based on molecular rather than polymeric materials to maximize resolution. MTR Resist absorbance of greater than 18 μm-1 has been measured. Here we present recent NXE3400 results where, by modifying the PAG to optimize the reactions rates in the MTR mechanism, we have reduced the dose requirement compared to the orthodox high opacity MTR resists previously presented. Lines of 14 nm width at p28 nm can be patterned at a dose between 21 mJ/cm2 and 48 mJ/cm2 dependent on formulation ratio, with optimum LWR (3.9 nm, biased) occurring at 43 mJ/cm2 with a film thickness of 20.7 nm. Similarly, we present p34 pillars patterned between 21 mJ/cm2 and 59 mJ/cm2 doses for 17 nm diameter pillars, with a minimum LCDU for 19 nm diameter pillars of 3.05 nm occurring with a 21.7 nm FT at 58 mJ/cm2. The same resist can pattern p36 pillars at 52 mJ/cm2 with an LCDU of 3.44 nm at 18 nm diameter with no measured defects between 15.9 nm and 18.1 nm diameter. The impact of the substrate (such as use of various organic underlayers or SOG layers) on defectivity issues such as bridging or falling pillars will be presented here.

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Section: Underlayer Optimisationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

EUV lithography patterning using multi-trigger resist

Popescu¹,

O'Callaghan²,

McClelland³

et al. 2023

Advances in Patterning Materials and Processes XL

View full text Add to dashboard Cite

show abstract

“…Transfer of lines and pillar patterns from MTR films using SiN as a hard mask and standard etch processes, even from thin films (26 nm post-coat; 24 nm post-development) has been demonstrated. [22] MTR Generation 2 (Gen2) was introduced in 2022, and initial results were presented. [19] In particular, we showed that good lithographic performance for P28 L/S with doses below 20 mJ/cm 2 and p36 and p34 hexagonal pillars with doses below 30 mJ/cm 2 .…”

Section: Introductionmentioning

confidence: 99%

“…[19] In particular, we showed that good lithographic performance for P28 L/S with doses below 20 mJ/cm 2 and p36 and p34 hexagonal pillars with doses below 30 mJ/cm 2 . [22,23] More recently we have explored three separate routes to significantly improve the Z-factor of the MTR system, either by increasing the activation rate of the monomer activation (Gen2.1); adjusting the relative reaction rates of the initiation and propagation rates of the ROP (Gen2.2); and via a more efficient multi-trigger quenching mechanism (Gen2.3). Additionally, the advantages gained by each approach are not correlated, and thus can be combined for further improvements of the MTR Z-factor (Gen2.4 and Gen 2.5) [24,25].…”

Section: Introductionmentioning

confidence: 99%

EUV lithography patterning using multi-trigger resist

Popescu,

O'Callaghan,

McClelland

et al. 2024

Advances in Patterning Materials and Processes XLI

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Irresistible Materials is developing a novel photoresist for EUV lithography including high-NA patterning. A major concern for the key research area of high-NA EUV resists is that stochastics in such resist materials can lead both to roughness and defects causing failures, which means high-NA resists remain a priority research area. We are developing a photoresist based on the multi-trigger concept, which seeks to suppress line edge roughness using a new photoresist mechanism, and which is based on molecular rather than polymeric materials to maximize resolution. It also has relatively high EUV absorbance to increase photon capture despite the need for thin films in high-NA due to limited depth-of-focus.By modifying the MTM molecule, crosslinker and PAG, both individually and in combination, we can optimize the reaction rates in the MTR mechanism. Different combinations have been designated Gen 2.1 to Gen 2.6 and show an LWR improvement in Gen 2.4, 2.5 and 2.6 combinations. Here we present the lithographic performance at pitch 28nm dense line/space where 14.1 wide lines were patterned at 59 mJ/cm 2 with an unbiased LER of 2.09 nm using a Gen 2.4 resist. We show hexagonal pillar results: pitch 32 nm patterned at 42 mJ/cm 2 to obtain a pillar diameter of 16 nm with an unbiased LCDU of 2.8 nm; and additionally p32 pillars of 16 nm diameter were patterned at 74 mJ/cm 2 with an unbiased LCDU of 2.7nm; and of 18.5 nm diameter at 82 mJ/cm 2 with an unbiased LCDU of 2.3nm. We also show data which shows using a Gen 2.6 resist can reduce the LCDU of p32 hex pillars by 0.2 nm and biased LWR of p28 l/s by 0.3 nm compared to a comparable Gen 2.4 resist.Performance improvements such as reduced roughness and defectivity can also be shown to be affected by choices such as underlayer and developer. Additionally, the modification of the developer can be shown to influence the patterning performance of the resist at high resolution.

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Recent accomplishments in EUV lithography patterning for multi-trigger resist

Popescu¹,

O'Callaghan²,

McClelland³

et al. 2022

International Conference on Extreme Ultraviolet Lithography 2022

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EUV lithography is becoming established in high volume manufacturing but there are still many challenges to be overcome within the ecosystem including next generation exposure tools and the materials used in the patterning stack. EUV photoresists with the appropriate capability to support future roadmap requirements such as high-NA remain a high priority area of research. EUV photons have significantly higher energy than in previous photolithographic techniques, and the resist is exposed by radiation chemistry routes rather than the well-known photochemistry from earlier nodes. In addition, resists must contend with much higher photon-shot noise, require high EUV absorbance to offset the need for very thin films, especially in High-NA EUV, where the depth of focus will be less than 20 nm, and ultimately the theoretical resolution limits of EUV will approach the size of typical photoresist molecules. We are developing a new type of photoresist based on the multi-trigger concept, which seeks to suppress line edge roughness using a new photoresist mechanism, and which is based on molecular rather than polymeric materials to maximize resolution.Here we present results showing improved lithography accomplishments due to the enhancement of the highopacity multi trigger resist system. We present a range of process conditions and formulation variations including substrate changes which impact roughness and defectivity. The lithographic performance at pitch 28 nm patterned on an ASML NXE3400 scanner is presented on a variety of substrates. Lines with a width of 12.5 nm can be patterned at 59 mJ/cm 2 with a biased LWR of 3.9 nm using a resist spun on the Brewer Optistack AL412 underlayer (12 nm thickness). We also present results on SOG/SOC stacks and the optimization required of the substrate to improve LWR and decrease defectivity. We further present results where we have been targeting sub-30 mJ/cm 2 patterning. Introducing an alternative PAG but maintaining constant formulation and process conditions has enabled the patterning of p28 lines lines/spaces, with 12 nm lines having been patterned at a dose of 17.5 mJ/cm 2 and a film thickness of 14.5 nm. Work is continuing to reduce the LWR whilst maintaining a sub 30 mJ/cm 2 dose. Multi-trigger resist has also been used to pattern pillars arranged in a hexagonal pattern. We show results at pitch 36 nm, again patterned on an ASML NXE3400, exposed at 66 mJ/cm 2 to obtain a pillar diameter of 18 nm with a biased LCDU of 3.6 nm. We also show pitch 34 nm hexagonal pillars, patterned at 65 mJ/cm 2 to obtain a pillar diameter of 17 nm with a biased LCDU of 3.6 nm with a focus window of over 60 nm. A film thickness of 22 nm was used. Additionally, carefully controlling the rates of the various reactions in the MTR mechanism, we have shown that we can reduce the dose required for 19 nm diameter hexagonally arranged pillars at p34 to 28 mJ/cm 2 with a biased LCDU of 4.3 nm using a 17 nm resist film thickness.

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Component optimisation in the multi-trigger resist

Cited by 4 publications

References 0 publications

EUV lithography patterning using multi-trigger resist

EUV lithography patterning using multi-trigger resist

EUV lithography patterning using multi-trigger resist

Recent accomplishments in EUV lithography patterning for multi-trigger resist

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