Characterization and acid diffusion measurements of new strong acid photoacid generators

Yamamoto

Kobayashi

et al. 2014

Jpn. J. Appl. Phys.

Extreme ultraviolet (EUV) lithography is the most promising candidate for the high-volume production of semiconductor devices with half-pitches of sub-10 nm. An anion-bound polymer (ABP), in which the anion part of onium salts is polymerized, has attracted much attention from the viewpoint of the control of acid diffusion. In this study, the acid generation mechanism in ABP films was investigated using electron (pulse), γ, and EUV radiolyses. On the basis of experimental results, the acid generation mechanism in anion-bound chemically amplified resists was proposed. The major path for proton generation in the absence of effective proton sources is considered to be the reaction of phenyl radicals with diphenylsulfide radical cations that are produced through hole transfer to the decomposition products of onium salts.

Section: Introductionmentioning

confidence: 99%

Acid generation mechanism in anion-bound chemically amplified resists used for extreme ultraviolet lithography

Yamamoto

Kobayashi

et al. 2014

Jpn. J. Appl. Phys.

“…[3][4][5] The increase in acid generator concentration and the suppression of the subsequent acid diffusion is one way to simultaneously improve resolution and LER. [6][7][8][9][10][11] On the other hand, the feature size is shrinking so markedly that the uniformity of acid generator distribution in resist matrices is becoming a serious problem. The phase separation between resist components has also been suggested.…”

mentioning

confidence: 99%

Electron and Hole Transfer in Anion-Bound Chemically Amplified Resists Used in Extreme Ultraviolet Lithography

Yamamoto

Utsumi

et al. 2013

Appl. Phys. Express

The uniformity of acid generator distribution and the length of acid diffusion are serious problems in the development of resist materials used for the 16 nm node and below. Anion-bound polymers in which the anion part of onium salts is polymerized have attracted much attention for solving these problems. In this study, the reaction mechanism of an anion-bound polymer in cyclohexanone was clarified using pulse radiolysis. The design of an efficient electron and hole transfer system is essential to the enhancement of resist performance.

“…For the realization of sub-10 nm fabrication, the control of acid diffusion is an important issue. [7][8][9][10][11][12] Anion-bound polymers (ABPs), in which the anion part of onium salts (acid generators) is polymerized, have attracted much attention from the viewpoint of the reduction in acid diffusion length. [13][14][15] Also, it has been pointed out that the acid generator concentration should be increased to increase the probability of the interaction between secondary electrons and acid generator molecules for the reduction in line edge roughness (LER) in the sub-10 nm region.…”

Section: Introductionmentioning

confidence: 99%

Modeling and simulation of acid generation in anion-bound chemically amplified resists used for extreme ultraviolet lithography

Kawana

Hirayama

et al. 2015

Jpn. J. Appl. Phys.

Extreme ultraviolet (EUV) lithography is the most promising candidate technique for the high-volume production of semiconductor devices with half-pitches of sub-10 nm. An anion-bound polymer, in which the anion part of onium salts is polymerized, has attracted much attention from the viewpoint of the control of acid diffusion. In this study, we modeled the acid generation processes in the anion-bound chemically amplified resists upon exposure to EUV radiation and developed a Monte Carlo simulation code. Using the developed simulation code, the dependence of the quantum efficiency of acid generation on the concentration of acid generator units was calculated. The calculated quantum efficiencies well agreed with the experimental values with a fitting error of less than 10%. The thermalization distance was considered to be approximately 3 nm. The blur of proton distribution intrinsic to the reaction mechanisms of anion-bound chemically amplified resists was roughly estimated to be 4.5–6.5 nm.