Fluorinated Acid Amplifiers for EUV Lithography

Over the past decade, the low intensity of extreme ultraviolet (EUV) light sources has been the most critical issue in the development of a promising, next-generation, high volume manufacturing (HVM) EUV lithography method. Specifically, enhancing the sensitivity of EUV resists to compensate for this low intensity is one of the most critical challenges for HVM implementations of EUV lithography. However, EUV light source power intensity remains one order less than the required value. Sensitivity enhancement of an EUV resist without any loss in other important properties such as resolution is inadequate to compensate for the low intensity of EUV sources in conventional EUV single exposure. Therefore, we propose a method for increasing the resist sensitivity considerably by combining the lithography of 1 st EUV pattern exposure with a 2 nd UV flood exposure (PF combination lithography) and a photosensitized chemically amplified resist (PS-CAR). This method achieves high sensitivity enhancement not only with EUV but also with electron-beam, ArF, and other types of pattern exposure. Thus, a sensitivity increase of more than one order without any loss in space resolution was achieved compared with conventional lithography by PF combination lithography of 1 st EB pattern exposure with 2 nd UV flood exposure and PS-CAR. Differences between EB and EUV resists include energy absorption processes, and the resist sensitivities of EUV can be predicted easily from the exposure results of EB lithography. Therefore, the reaction mechanism of EUV pattern exposure-UV flood exposure combination lithography of PS-CAR can be essentially evaluated with EB pattern exposure-UV flood exposure combination lithography of PS-CAR.

Section: Sensitivity Enhancement Methodsmentioning

confidence: 99%

Super High Sensitivity Enhancement by Photo-Sensitized Chemically Amplified Resist (PS-CAR) Process

Tagawa

Enomoto

Oshima

2013

“…Product analysis experiments 14 showed that the pathways for the unwanted, noncatalytic decomposition reactions involved either S N 2 or S N 1 reactions between phenolic nucleophiles in polymer films or in solution and the primary sulfonic ester bonds ( Figure 4). We, therefore, devised a strategy for blocking both decomposition pathways by preparing acid amplifiers with a trifluoromethyl (-CF 3 ) group alpha to the sulfonic ester.…”

Section: 1mentioning

confidence: 99%

“…Combining both the olefin trigger and the fluorinestabilized capacity into one trigger-body design, we produced acid amplifiers AA4 and AA5 ( Figure 5), which are designed to produce pentafluorobenzene-sulfonic acid (C 6 F 5 SO 3 H, PFBS) and triflic acid (CF 3 SO 3 H, TfOH), respectively. Using some of our original body-trigger designs, [14][15][16][17][18] we have been able to prepare AAs that generate PFBS, but, until now, we have never been able to prepare stable AAs that make acids any stronger than PFBS acid. Using the olefin/-CF 3 design, not only have we been able to prepare AAs that generate PFBS, but for the first time, we are able to prepare an AA that generates TfOH…”

Section: 1mentioning

confidence: 99%

See 1 more Smart Citation

Fluorine-Stabilized Acid Amplifiers for Use in EUV Lithography

Hosoi

Cardineau

Kruger

et al. 2012

Self Cite

This paper presents two new concepts that together provide a 100,000X improvement in stability for AAs that produce highly-fluorinated, strong sulfonic acids. These two new design concepts are based on (1) an olefin-trigger structure and (2) a trifluoromethyl groupalpha to the sulfonic ester. These approaches led to the synthesis of the first stable acid amplifier that generates triflic acid and for the synthesis of AAs that are stable enough to be used as monomers in free-radical polymerization reactions yet produce very strong, fluorinated acids. Lastly, we present preliminary results where one new AA is able to improve the LER of a control resist from 4.6 ± 0.5 nm to 2.1 ± 0.1 nm.

“…Our approch is a logical extension of our group's design of acid amplifiers [10][11][12][13], in which specifically-designed blocking groups protect sulfonic acids. In DD-CAMP, however, our specially-designed blocking groups protect polymer-bound carboxylic acids that provide the solubility switches in these positive-tone resists.…”

Section: Introductionmentioning

confidence: 99%

Higher-Order Lithography: Double-Deprotected Chemically Amplified Photoresists (DD-CAMP)

Soucie

Earley

Hosoi

et al. 2017

The synthesis and lithographic evaluation of 193-nm and EUV photoresists that utilize a higher-order reaction mechanism of deprotection is presented. Unique polymers utilize novel blocking groups that require two acid-catalyzed steps to be removed. When these steps occur with comparable reaction rates, the overall reaction should be higher order (≤ 1.85). The LWR of these resists is plotted against PEB time for a variety of compounds to acquire insight into the effectiveness of the proposed higher-order mechanisms. Evidence acquired during testing of these novel photoresist materials supports the conclusion that higher-order reaction kinetics leads to improved LWR vs. control resists.