## REAGENT FOR ENHANCING GENERATION OF CHEMICAL SPECIES 

## CROSS-REFERENCE TO RELATED APPLICATIONS 

This application is a national phase entry under 35 U.S.C. § 371 of International Patent Application PCT/ JP2014/004119, filed Aug. 7, 2014, designating the United States of America and Published in English as International Patent Publication WO 2015/019616 Al on Feb. 12, 2015, which claims the benefit under Article 8 of the Patent Cooperation Treaty and under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 61/863,354 filed on Aug. 7, 2013, the disclosure of each of which is hereby incorporated herein in its entirety by this reference. 

Several aspects of this disclosure relates to the fields of a reagent enhancing a generation of a chemical species such as acid and base. An intermediate formed from the reagent function as a photosensitizer. 

Current high-resolution lithographic processes are based on chemically amplified resists (CARs) and are used to pattern features with dimensions less than 100 nm. 

A method for forming pattern features with dimensions less than 100 nm is disclosed in U.S. Pat. No. 7,851,252 (filed on Feb. 17, 2009; issued Dec. 14, 2010), the disclosure of which is hereby incorporated herein in its entirety by this reference. 

Reagents that enhance generation of a chemical species such as acid and a composition are disclosed herein. Typi› cally, such reagent assists the generation of Briinsted acid or base from a precursor. Furthermore, such reagent can apply 40 to the generation of Lewis acid and base. Typically, such reagent generates a ketone or aldehyde compound by react› ing with a chemical species such as acid. More typically, such reagent has a protecting group for the carbonyl group 45 of the ketone or aldehyde compound. The ketone or alde› hyde compound is generated by deprotection reaction of the reagent by acid or base. The generated ketone or aldehyde compound acts as the sensitizer that enhances a generation 50 of acid or base from the precursor by an irradiation of the ketone or aldehyde compound of which excited state can transfer its energy or electron to the precursor. The precursor generates the chemical species after receiving the energy or the electron from the excited state of the ketone or aldehyde compound. Since several sensitizers are required to have 55 high electron donor character to enhance electron transfer to the precursor, such sensitizers have at least one electron› donating group on the aromatic ring such as an alkyl group, an alkoxy group, an alkyl amino and hydroxyl group, and an alkyl thio group. 60 

For example, a composition containing a reagent that is to form such sensitizer, a precursor that is to form a chemical species, and a compound that is to react with the chemical species can be applied as photoresist to manufacturing of electronic devices such as a semiconductor device and an 65 electro-optical device. For example, after a coating film of the composition is exposed to an excimer laser, an extreme 

## TECHNICAL FIELD 

## BACKGROUND 

## BRIEF SUMMARY 

ultraviolet (EUV) light and an electron beam (EB) are used in a first step. A chemical species generated in the coating film in the first step reacts with the reagent to form such sensitizer. In a second step, the coating film can be exposed to a light, which wavelength is longer than that of the EUV light, and a UV light, which wavelength is longer than 200 nm, or a visible light. In the second step, the generated sensitizer enhances a reaction from the precursor to form a chemical species. Typically, the chemical species that reacts with the reagent to form the sensitizer is identical with the chemical species that is formed from the precursor. There› fore, the sensitizer is generated even in the second step. In other words, the formation of the sensitizer is chemically amplified. The composition can be used as a chemically amplified photoresist containing a photoacid generator (PAG) and a resin containing a protective group, such as an ester and ether group, which is to decompose by reacting with acid generated from the PAG. The photoresist further contains a reagent having a protecting group of a carbonyl group, which is to react with acid generated from PAG to form a corresponding ketone or aldehyde compound. The ketone or aldehyde compound acts as a sensitizer enhancing the formation of an acid from PAG. A reaction of reagent with the generated acid results in chemically amplified formation of the ketone compound or aldehyde compound. 

Triplet sensitizers, electron-accepting sensitizers, and energy-accepting sensitizers are also utilized for enhancing generation of a chemical species such as acid and base. 

It is preferred that the reagent that is protected by an acid-dissociable group is not excited by a light irradiated in the second step. Alternatively, it is preferred that to attain the high resolution lithographic property of a sensitizer, an unexposure area in the first step is inactive for the light with which the reagent is irradiated in the second step. Therefore, it is preferred that the reagent is protected by a protective group such as an acyclic or cyclic acetal group, an acyclic or cyclic dithio acetal group, or an acyclic or cyclic mono› thio acetal group. Basically, such groups do not contribute to absorption of a light of which wavelength is equal to or longer than 300 nm. 

A reagent relating to an aspect of this disclosure wherein a product is generated from the reagent and the product enhances a generation of a first chemical species from a precursor by a first reaction of the precursor. 

A reagent relating to an aspect of this disclosure includes a first moiety including a protecting group and a second moiety that includes a pi-conjugated system. With regard to the reagent, it is preferred that a deprotection reaction of the first moiety occurs by a reaction of the first moiety with a first chemical species to form a product that absorbs a light, which wavelength is equal to or longer than 200 nm, the wavelength of the first moiety. 

With regard to the reagent, it is preferred that the product enhances a generation of the first chemical species from a precursor. 

With regard to the reagent, it is preferred that the first chemical species is acid. 

With regard to the reagent, it is preferred that the product enhances the generation of the first chemical species from the precursor by absorbing a first light, which wavelength is a first wavelength and acting as a sensitizer. 

With regard to the reagent, it is preferred that a second reaction of the reagent with a second chemical species results in the product. 

With regard to the reagent, it is preferred that an irradia› tion of a precursor with a second light or a particle ray results in a second chemical species. 

