Excluded volume effects caused by high concentration addition of acid generators in chemically amplified resists used for extreme ultraviolet lithography

Abstract

The resolution of lithography used for the high-volume production of semiconductor devices has been improved to meet the market demands for highly integrated circuits. With the reduction in feature size, the molecular size becomes non-negligible in the resist material design. In this study, the excluded volume effects caused by adding high-concentration acid generators were investigated for triphenylsulfonium nonaflate. The resist film density was measured by X-ray diffractometry. The dependences of absorption coefficient and protected unit concentration on acid generator weight ratio were calculated from the measured film density. Using these values, the effects on the decomposition yield of acid generators, the protected unit fluctuation, and the line edge roughness (LER) were evaluated by simulation on the basis of sensitization and reaction mechanisms of chemically amplified extreme ultraviolet resists. The positive effects of the increase in acid generator weight ratio on LER were predominant below the acid generator weight ratio of 0.3, while the negative effects became equivalent to the positive effects above the acid generator weight ratio of 0.3 owing to the excluded volume effects.

Regression analysis of photodecomposable quencher concentration effects on chemical gradient in chemically amplified extreme ultraviolet resist processes

“…It has been reported for chemically amplified electron beam resists that PDQ also works as an information receiver and its effect is the same as that of PAG. 39) From the information receiver viewpoint, C PAG and C PDQ are interchangeable, which is considered to be due to the apparent symmetric relationship between C PAG and C PDQ . Note that PAG and PDQ have different roles besides being an information receiver.…”

“…[13][14][15][16][17][18] For sub-10 nm fabrication, the increase in acid generator concentration is inevitable and the excluded volume effect of acid generators cannot be neglected. 19) A photodecomposable quencher (PDQ) is an important material option because it can be used to reduce the concentration of low-molecular-weight components (acid generators and quenchers) owing to its sensitization effect.…”

Sensitization of polymethacrylate resist with adding acid-generating promoters upon exposure to EUV light

“…[24][25][26] However, to prevent deterioration of the resolution of the resist, the PAG loading capacity needs to be limited. 27,28) Recently, we proposed an acid-generating promoter (AGP) to improve the resist performance by increasing the quantum yield of the acid generated immediately after CAR exposure to ionizing radiation such as electron beam (EB) and EUV light. 29,30) The addition of AGP to poly(hydroxystyrene-acrylate) copolymer resists has also been shown to increase EB and EUV sensitivity.…”