Comparison of Resist Family Outgassing Characterization between EUV and EB

Takagi, Isamu; Takahashi, T.; Sugie, Norihiko; Katayama, Kazuhiro; Kikuchi, Yukiko; Shiobara, Eishi; Tanaka, Hiroyuki; Inoue, Soichi; Watanabe, Takeo; Harada, Tetsuo; Kinoshita, Hiroo

doi:10.2494/photopolymer.26.673

Cited by 9 publications

(5 citation statements)

References 6 publications

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“…13 Although outgassing has received a great deal of attention due to its impact on throughput and damages to optics, only several studies have been reported regarding chemistry of outgassing. [19][20][21][22][23] There have been only one report that deals with influence of Ea on outgassing. 23 Therefore, we have investigated, in particular, effects of Ea on outgassing using a wide variety of polymers with a different acid labile groups (ALG).…”

Section: Outgassing Issue Of Low Ea Polymermentioning

confidence: 95%

Novel EUV resist materials design for 14nm half pitch and below

et al. 2014

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Polymers with a different Tg and activation energy were prepared to clarify influences of acid diffusion on resolution at 15 nm half-pitch (hp) and 14 nm hp using a EUV micro-field exposure tool (MET) at LBNL. Resolution on such a narrow pattern was limited by collapse and pinching. Clear relationship between pinching numbers and polymer Tg indicates that acid diffusion is one of major contributors on the pinching. In addition, polymers with a low thermal activation energy (Ea) on deprotection were effective for reducing pinching. This is probably originated from its high chemically amplification character even in low post-exposure bake (PEB) temperature to obtain both large chemical contrast and short acid diffusion. On the other hand, a good correlation between a cleanable outgassing amount and Ea indicates trade-off relationship between outgassing and resolution. Advantages of n-butyl acetate (nBA) developer have been investigated in viewpoint of dissolution uniformity. Surface roughness of a non-patterned resist film at half-exposed area, which was well correlated with LWR, was measured by AFM as indicator of uniformity in development process. To avoid any differences in resist chemistry other than development process, cross linking negative tone resist was applied for this study. The surface roughness obtained by nBA, which is conventional negative-tone imaging (NTI) developer, was 32 % lower than that obtained by 2.38 % TMAH solution. NTI resist system with a nBA developer and optimized resist reduced LWR from 4.8 nm to 3.0 nm in comparison with conventional positive tone resist with a 2.38 % TMAH developer. In addition, advantage on semi-dense trench patterning was well defined. New EUV sensitizer with 1.15 times higher EUV absorption resulted in 1.15 times higher acid yield by EUV exposure. Lithography performance of the new EUV sensitizer has been investigated by MET at SEMATECH Albany. Sensitivity was indeed improved from 20 mJ/cm 2 to 17 mJ/cm 2 according to the acid yield increase, but resolution was significantly degraded.

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Section: Outgassing Issue Of Low Ea Polymermentioning

confidence: 95%

Novel EUV resist materials design for 14nm half pitch and below

et al. 2014

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“…Moreover, we studied noncleanable contamination on the unexposed area and clarified its dependency on the geometry of the WS in the vacuum chamber [3][4][5][6]. Moreover the comparison of the cleanable and noncleanable contamination in the resist family, which consisted of the same components with various protecting ratios and PAG loading, showed a good correlation [7,8]. However, the comparison of noncleanable contamination for resists with various components is not sufficient.…”

Section: Introductionmentioning

confidence: 97%

Contribution of EUV resist components to the non-cleanable contaminations

Shiobara¹,

Takahashi²,

Sugie³

et al. 2014

SPIE Proceedings

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The suppression of outgassing from extreme ultraviolet (EUV) resist needs to be addressed for realizing EUV lithography (EUVL) because outgassing is likely the main contributor to the contamination of mirror optics in EUV scanners, which results in reflectivity loss. Resist outgassing causes two types of contamination: cleanable contamination, involving hydrocarbon contaminants, and noncleanable contamination, involving noncarbon components. The relation of cleanable contamination between EUV-and electron beam (EB)-based evaluations is linear. However, the relation of noncleanable contamination is not clear. In this study, we investigated the contribution of EUV resist components to noncleanable contamination using different photoacid generator components. The cleanability of noncleanable elements (sulfur, iodine, chlorine, and bromine) in contamination films was measured and compared for the EUV-and EB-based outgas testers. The result suggested that the chlorine and bromine contaminants were completely removed after cleaning. On the other hand, sulfur and iodine remained even after cleaning. This suggested that the careful use of iodine in resist materials is necessary due to its high photoabsorption and low cleanability. In addition, the cleaning rate and noncleanability of contaminants in the EUV-based test were larger than in the EB-based test. This suggests that the contamination film in the EUV-based test is more porous than that in the EB-based test.

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“…One of the outgas testers used EUV light to expose the resist and WS. The other outgas tester used e-beams for the exposure of resist and WS, and it was named as EUVOM-9000 (Litho Tech Japan Corp.) [6][7][8]. The EUV type tester named HERC was developed for basic outgassing research and not for the resist qualification inorder to avoid the exposure in the scanner.…”

Section: Introductionmentioning

confidence: 99%

EUV resist outgassing analysis for the new platform resists at EIDEC

Shiobara¹,

Kikuchi²,

Mikami³

et al. 2016

Extreme Ultraviolet (EUV) Lithography VII

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The suppression of outgassing from the EUV resist is one of the significant challenges, which has to be addressed for realizing EUV lithography (EUVL). The outgassing might be the main contributor involved in the contamination of the mirror optics in scanners. This may result in reflectivity losses. The pragmatic outgassing test that utilizes the witness sample (WS) was used as a general method to quantify the outgassing level for commercially available chemically amplified resists (CAR). There are two types of contaminations. The first type of contamination involves a cleanable contamination that mainly comprises hydrocarbons that can be removed by the hydrogen radical cleaning. Another type of contamination includes the noncleanable contamination that remains on the WS even after hydrogen radical cleaning. Several outgas qualification results were evaluated at the EIDEC [1, 2]. The data indicated that contaminations by the CAR mainly comprised the cleanable contaminations. The data also indicated that there were almost negligible noncleanable contaminations from the CAR.EUV resist communities accelerate the development of high sensitivity resists to compensate the low power of the EUV source. Nonchemically amplified resist (nonCAR) with a new platform is a candidate for high sensitivity resists. The nonCAR includes some types of metal elements with high absorbance for EUV light. There is very limited research on the outgassing characteristics of the nonCAR. In this study, we considered an EUV exposure process in the actual EUV scanner and EUV resists were exposed in a hydrogen environment. A potential risk could result from the reaction of the hydrogen radicals generated by the EUV light with the metal elements in the nonCAR and the metal hydride outgases from the resist. This would result in a noncleanable contamination on the EUV mirror [3]. The knowledge with respect to outgassing from an organic metal complex is insufficient even in a vacuum condition. Hence, the study involved the preparation of certain types of organic metal complexes as model materials. Then, the outgassing evaluations for the materials were carried out as a fundamental studies in a vacuum condition. The results were reported in this study.

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Comparison of Resist Family Outgassing Characterization between EUV and EB

Cited by 9 publications

References 6 publications

Novel EUV resist materials design for 14nm half pitch and below

Novel EUV resist materials design for 14nm half pitch and below

Contribution of EUV resist components to the non-cleanable contaminations

EUV resist outgassing analysis for the new platform resists at EIDEC

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