Nanoparticle Photoresists: Ligand Exchange as a New, Sensitive EUV Patterning Mechanism

Kryask, Marie; Trikeriotis, Markos; Ouyang, Can; Chakrabarty, Sovik; Giannelis, Emmanuel P.; Ober, Christopher K.

doi:10.2494/photopolymer.26.659

Cited by 45 publications

(34 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resulting HfMAA nanoparticles have shown excellent EUV patterning capabilities with sensitivities of 4.2 mJ/cm 2 and resolution of ~20 nm. [1]- [3] All EUV exposures reported here were carried out at Lawrence Berkeley National Laboratories. In the past year, several material systems were investigated.…”

Section: Introductionmentioning

confidence: 99%

New developments in ligand-stabilized metal oxide nanoparticle photoresists for EUV lithography

et al. 2015

View full text Add to dashboard Cite

The introduction of EUV lithography to manufacturing requires the development of both new EUV exposure tools and photoresists. The main challenges for photoresists are to achieve high resolution, and low roughness patterning at very high sensitivity given the limited intensity of current sources. A new class of photoresist formed from ligand-stabilized metal oxide nanoparticles shows extraordinary sensitivity for EUV lithography. These nanoparticles are processed in traditional organic solvents for both deposition and development as negative tone resist; positive tone images are possible if the aqueous base developer is used in addition to a post-exposure bake step. This paper presents new developments in the study of ligand-stabilized nanoparticle photoresists for EUV lithography. It is our current understanding that a key aspect of the solubility change of these photoresists during exposure involves ligand displacement by anions generated from photoactive compounds such as sulfonic acid photoacid generators. Both positive and negative tone patterning are possible and depend on thermal treatment history and choice of developer. On the basis of a non-chemically amplified ligand exchange mechanism, new resist structures were created. Both aromatic and aliphatic carboxylic acids with different functional groups have been studied in the formation of the nanoparticles and include dimethylacrylic acid, isobutyric acid, toluic acid. It has been shown that those nanoparticles with higher binding affinity ligands show better resolution and line edge roughness under EUV exposure. Some formulations demonstrate EUV sensitivity as high as 1.4 mJ/cm 2 , while other formulations demonstrate that improved LER values of 3-5nm. The overall resolution, sensitivity and roughness tradeoff has been evaluated and provides an understanding of structure -property relationships. In this paper, we also discuss major efforts on the further understanding of the patterning mechanism. By testing the dissolution rate and plotting it in Hansen interaction triangles, we can compare the differences between different formulations and choose a suitable developer for each formulation. We also used the dissolution rate study to confirm the important role of PAG and ligand exchange for pattern formation. In addition, aspects of the EHS properties of these new photoresists have been investigated and will be discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

New developments in ligand-stabilized metal oxide nanoparticle photoresists for EUV lithography

et al. 2015

View full text Add to dashboard Cite

show abstract

“…ZrO2-p-toluic acid resists compositions were formulated containing 5 wt-% of a nonionic photoacid generator (PAG) as per protocols mentioned in earlier studies [12]. The resist formulation was spin coated onto silicon wafers at 4000 rpm for 40 nm films.…”

Section: Euv Results Of Nanoparticles With Aromatic Ligandsmentioning

confidence: 99%

Oxide Nanoparticle EUV (ONE) Photoresists: Current Understanding of the Unusual Patterning Mechanism

Jiang

Zhang

et al. 2015

J. Photopol. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

In the past few years, industry has made significant progress to deliver a stable high power EUV scanner and a 100 W light source is now being tested on the manufacuring scale. The success of a high power EUV source demands a fast and high resolution EUV resist. However, chemcially amplied resists encounter unprecedented challenges beyond the 22 nm node due to resolution, roughness and sensitivity tradeoffs. Unless novel solutions for EUV resists are proposed and further optimzed, breakthroughs can hardly be achieved. Oxide nanoparticle EUV (ONE) resists stablized by organic ligands were originally proposed by Ober et al. Recently this work attracts more and more attention due to its extraordinanry EUV sensitivity. This new class of photoresist utilizes ligand cleavage with a ligand exchange mechanism to switch its solubilty for dual-tone patterning. Therefore, ligand selection of the nanoparticles is extremely important to its EUV performance.

show abstract

“…The patterning mechanism of ligand stabilized nanoparticles resist involves both ligand exchange and particles aggregations. [5]- [7] The binding affinity of ligands on the as-prepared resists are weaker and thus replaced by the ligands generated from photoactive compound during exposure. [8] The loss of ligands initiates particle aggregation which leads to the nanoparticles being less soluble in organic developer, resulting in negative tone patterning.…”

Section: Introductionmentioning

confidence: 99%

Systematic study of ligand structures of metal oxide EUV nanoparticle photoresists

Jiang

Zhang

et al. 2015

SPIE Proceedings

Self Cite

View full text Add to dashboard Cite

Ligand stabilized metal oxide nanoparticle resists are promising candidates for EUV lithography due to their high sensitivity for high-resolution patterning and high etching resistance. As ligand exchange is responsible for the patterning mechanism, we systematically studied the influence of ligand structures of metal oxide EUV nanoparticles on their sensitivity and dissolution behavior. ZrO 2 nanoparticles were protected with various aromatic ligands with electron withdrawing and electron donating groups. These nanoparticles have lower sensitivity compared to those with aliphatic ligands suggesting the structures of these ligands is more important than their pka on resist sensitivity. The influence of ligand structure was further studied by comparing the nanoparticles' solubility for a single type ligand to mixtures of ligands. The mixture of nanoparticles showed improved pattern quality.

show abstract

Nanoparticle Photoresists: Ligand Exchange as a New, Sensitive EUV Patterning Mechanism

Cited by 45 publications

References 5 publications

New developments in ligand-stabilized metal oxide nanoparticle photoresists for EUV lithography

New developments in ligand-stabilized metal oxide nanoparticle photoresists for EUV lithography

Oxide Nanoparticle EUV (ONE) Photoresists: Current Understanding of the Unusual Patterning Mechanism

Systematic study of ligand structures of metal oxide EUV nanoparticle photoresists

Contact Info

Product

Resources

About