content_image/902162.jpg content_image/902166.jpg content_image/902167.jpg
(C) a photoacid generator, and 

(D) a basic compound. 

Solvent 

The organic solvent (A) used herein may be any organic solvent in which the base resin, acid generator, and other components are soluble. Illustrative, non-limiting, examples of the organic solvent include ketones such as cyclohexanone and methyl amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, l-methoxy-2-propanol, and l-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, pro› pylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono› tert-butyl ether acetate; and lactones such as y-butyrolactone. These solvents may be used alone or in combination of two or more thereof. Of the above organic solvents, it is recom› mended to use diethylene glycol dimethyl ether, l-ethoxy-2- propanol, propylene glycol monomethyl ether acetate, and mixtures thereof because the acid generator is most soluble therein. 

An appropriate amount of the organic solvent used is 200 to 3,000 parts, especially 400 to 2,500 parts by weight per 100 parts by weight of the base resin. 

Resin 

In addition to the polymer comprising recurring units hav› ing formula (1) or (2), the base resin in the resist composition may further comprise another resin component. Specifically the other resin component used herein includes, but is not limited to, those polymers comprising units of the following formula (Rl) and/or (R2) and having a weight average molecular weight (Mw) of 1,000 to 100,000, especially 3,000 to 30,000, as measured by gel permeation chromatography (GPC) versus polystyrene standards. 

<img src='content_image/902162.jpg'>

<img src='content_image/902166.jpg'>

<img src='content_image/902167.jpg'>

Herein, R $^{001 }$is hydrogen, methyl or CH$_{2}$ CO$_{2}$R 003 . 003 

R$^{002 }$is hydrogen, methyl or CO$_{2}$R . 

R$^{003 }$is a straight, branched or cyclic C$_{1 }$-C$_{15 }$alkyl group, examples of which include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl, cyclopentyl, cyclohexyl, ethylcyclopentyl, butylcyclopentyl, ethylcyclohexyl, butylcyclohexyl, adamantyl, ethyladaman› tyl, and butyladamantyl. 

R$^{004 }$is hydrogen or a monovalent hydrocarbon group of 1 to 15 carbon atoms having at least one group selected from among fluorinated substituent groups, carboxyl groups and hydroxyl groups. Examples include hydrogen, carboxyethyl, carboxybutyl, carboxycyclopentyl, carboxycyclohexyl, car› boxynorbornyl, carboxyadamantyl, hydroxyethyl, hydroxy› butyl, hydroxycyclopentyl, hydroxycyclohexyl, hydroxynor› bornyl, hydroxyadamantyl, [2,2,2-trifluoro-l-hydroxy-l› (trifluoromethyl)ethyl]cyclohexyl, and bis[2,2,2-trifluoro-l› hydroxy-l-(trifluoromethyl)ethyl]-cyclohexyl. 

