San-Apro Ltd.

Extreme UV lithog. at 13.5 nm has become an essential technol. for the mass production of state-of-the-art semiconductor integrated circuits for use in devices such as smartphones.Chem. amplified resists are primarily used for their production, and several performance requirements have to be met to achieve fine patterning.The requirements are known for simultaneous achievement of resolution, low line edge roughness, high sensitivity, and low outgassing.As photoacid generators are ingredients for determine CARs sensitivity, high absorption of EUV light, acceptability of the secondary electron from matrix polymer, and high decomposability (high acid generation efficiency) are required in EUV lithog.Most onium-salt structures that have been proposed for use as EUV PAGs possess a sulfur atom at its center of cation.In this study, we focus on selenonium salts possessing selenium atoms at its center of cation, which exhibit strong absorption of EUV light, and evaluate their utility in EUV lithog.

In extreme UV (EUV) lithog. development, the reduction of line width roughness (LWR) is a one of the significant issues.It has been reported that the LWR of photoacid generator (PAG) bounded resist is lower than that of PAG blended resist.It is considered that the chem. composition distribution of PAG bounded resist is more uniform than PAG blended resist.However, it has not been evaluated systematically and exptl.In this study, we introduced the contact angle measurement method for the evaluation of the chem. composition distribution between PAG blended resist and PAG bounded resist.It is clarified that the resist thin film has a different chem. composition distribution from the center to the outside of wafer regardless of the type of resists.In particular, the chem. composition distribution of the bounded resist showed the opposite behavior to that the blended one.

Photo-irradiation responsible resins have attracted intense interest in research area of photolithog. technol. because of their application for semiconductors and organic EL displays.Although photosensitive resins including photoacid generators, which emit acidic moieties by photo-irradiation, have been developed, their utilization are limited because of corrosion of metals and resins due to residual acid.On the other hand, for the fabrication of materials available in long-term, resins containing photobase generators are focused because of prevention of the corrosions.However, there is no example of photobase generator in which strong bases are preparedFor the development of photobase generators, we purposed the investigation of basicity control based on the complexation of photoisomerization of a diarylethene derivative (BDAE) having boronate ring and 1,8- diazabicyclo[5.4.0]-7-undecene (DBU).Although decomposed products were obtained after UV-irradiation to an open-formed isomer of BDAE probably because of oxidative reaction, it was found that the basicity of a solution of a mixture of BDAE and DBU decreased due to complexation of DBU and phenylboronic acid produced by the decomposition of BDAE.