Masatoshi Echigo

Development of new xanthendiol derivatives applied to the negative-tone molecular resists for EB/EUVL

In this paper, we report the development of new xanthendiol derivatives applied to the negative-tone molecular resists for EB/EUVL. The new xanthendiol derivatives were easily synthesized by the condensation of aldehydes and dihydroxyaromatic compounds. We found 13,13’-biphenyl-bis(13H-benzoxanthen-2,11-diol) was showed the good applicability to the raw material for the resist for EB/EUVL. The EB patterning result showed the resist containing xanthendiol derivative could resolve the 20 nm half-pitch pattern, and 15 nm half-pitch patterns were partially resolved.

Development of molecular resists based on Phenyl[4]calixarene derivatives.

We have developed negative-tone molecular resist based on C-4-cyclohexylphenylcalix[4]resorcinarene(MGR108) and positive-tone molecular resist based on protected C-4-isopropylphenylcalix[4]resorcinarene (MGR104P). Both MGR108 and MGR104P showed high solubility in both conventional resist solvents such as propylene glycol monomethyl ether and conventional alkaline developer of 0.26N TMAHaq. In this paper, we show current performance of resists by EB lithography (EBL) and EUV lithography (EUVL).

Development of new phenylcalix[4]resorcinarene: its application to positive-tone molecular resist for EB and EUV lithography

We have developed new positive-tone molecular resist material, C-4-(2-methyl-2-adamantyloxycarbonylmethoxy) phenylcalix[4]resorcinarene (MGR110P). MGR110P showed high solubility in both conventional resist solvents such as propylene glycol monomethyl ether and cyclohexanone. MGR110P was single molecular without molecular weight disperse. A positive-tone molecular resist based on MGR110P was evaluated by EB lithography (EBL) and EUV lithography (EUVL). This resist could be developed a standard alkaline developer of 0.26N TMAHaq. EB patterning results showed the resolution of this resist on a HMDS primed Si wafer to be 40 nm line and space at an EB exposure dose of 28μC/cm2. The line edge roughness (LER) showed 3.8 nm at 50 nm line and space pattern at EB exposure dose of 26μC/cm2. Unfortunately, 30 nm line and space pattern collapsed. In addition, EUV patterning results showed the resolution on an organic layer substrate to be 45 nm line and space at an EUV exposure dose of 10.3 mJ/cm2. Unfortunately, 40 nm to 30 nm line and space pattern collapsed.

Development of molecular resists based on Phenyl[4]calixarene for EBL

In this paper, we report current performance of the negative-tone molecular resists based on calix[4]resorcinarene (CRA) by Electron Beam Lithography (EBL). We have developed hydroxyphenyl calix[4]resorcinarenes (H-CRAs) designed hydroxy-groups outer to adhere patterns to wafers. Hydroxy groups help patterns adhere to wafers, to restrain collapse of patterns. Moreover, we additionally controlled hydrophobicity of H-CRA by the alkyl-groups (R), which make the sensitivity higher. The negative-tone resist based on these H-CRAs shows well-defined 25-50nm half-pitch patterns, and the increase in hydrophobicity of H-CRA by the alkyl-groups (R) made the high sensitivity. Furthermore, the optimization of these resist formulation improved sensitivity and LER.

EUV sensitizer for resists and spin-on-carbon materials

We are developing the EUV sensitizer for resists and Spin-on-Carbon materials. In previous report, we reported that we had developed the novel materials containing the iodine having high EUV absorption ability, and EUV absorption rate proved to be calculable from density and element composition. In this report, we calculated the improvement rate of the EUV absorption rate when materials with high EUV absorption were used for EUV sensitizers. As the result of this, we found that materials with high EUV absorption were useful for EUV sensitizers. Additionally, we will also report on new materials with a high EUV absorption ability.

Development of the negative-tone molecular resists for EB/EUVL having high EUV absorption capacity and molecular design method

In this paper, we designed the synthesis of negative-type molecular resist materials for EB and EUVL exposure tools, and their properties were examined. The resist materials for EUVL have been required showing higher sensitivity for high throughput in the lithographic process, and expecting lower shot noise to improve a roughness. In EUVL process, the resist materials must be ionized by absorbing EUV to emit more secondary electrons. The EUV absorption of the synthesized resist materials was measured using their thin films on the silicon wafer, and it was observed that the ratio of EUV absorption of the synthesized resist was higher than in the comparison of that of PHS as a reference., i.e., 2.4 times higher absorption was shown. Furthermore, we examined the relationship between the ratios of EUV absorptions and functional groups of the resist materials. As the result, the sensitivity of resist materials under EUV exposure tool was consistent with their structures.

Development of heat resistant polyphenol compounds applied to the spin-on carbon hardmask

In this paper, we report the development of a new polyphenol, NF7177, applied to the Spin-On Carbon Hardmask and the thermosetting properties. The new polyphenol derivatives were easily synthesized by the condensation of aldehydes and dihydroxybiphenyl compounds. We found new polyphenol NF7177 was showed the good applicability to the raw material for the Spin-On Carbon Hardmask [1]. It was indicated that the heat resistance of NF7177 was due to cross-linking based on dehydration reaction. Furthermore the thermosetting properties seem to be depend on the number and position of OH group.

Investigation of correlation with the octanol water partition coefficient and the sensitivity of negative-tone molecular resists

In this paper, we report the investigation of correlation with the octanol water partition coefficient and the sensitivity of negative-tone molecular resists based on calix[4]resorcinarene (CRA) by Electron Beam Lithography (EBL). The sensitivity of negative-tone molecular resists were higher as the value of the Octanol water partition coefficient got smaller. It was confirmed that the octanol water partition coefficient was useful to the guess of sensitivity of negativetone molecular resists. Furthermore, we have developed calix[4]resorcinarenes showing well-defined sub 20nm halfpitch patterns.