US  10,031,416 B2  2  1  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.  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.  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 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 the first  chemical species is acid.  With regard to the reagent, it is preferred that the product  enhances a generation of the first chemical species from a  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.  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.  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.  Triplet sensitizers, electron-accepting sensitizers, and  energy-accepting sensitizers are also utilized for enhancing  generation of a chemical species such as acid and base.  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.  TECHNICAL FIELD  BACKGROUND  BRIEF SUMMARY  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  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  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  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. 