7  US 9,291,896 B2  8  L$_{2 }$ represents a single bond or an alkylene group.  Ar$_{2 }$ represents an (n+l)-valent aromatic ring group and in  the case of combining with R$_{22 }$to form a ring, Ar$_{2 }$ represents  an (n+2)-valent aromatic ring group.  n represents an integer of 1 to 4.  The resin (P) is a resin having a structure where in the  repeating unit represented by formula (1 ), a car boxy 1 group as  a polar group is protected by acetalization or ketalization with  a leaving group capable of decomposing and leaving by an  action of an acid.  In the case of performing negative development using an  organic solvent-containing developer, the resin (P) is a resin  capable of increasing in the polarity by the action of an acid to  decrease the solubility for the organic solvent-containing  developer, and in the case of performing positive develop- ment using an alkali developer, the resin (P) is a resin capable  of increasing in the polarity by the action of an acid to  increase the solubility for the alkali developer. Incidentally, in  the case of performing positive development using an alkali  developer, the carboxyl group as a polar group functions as an  alkali-soluble group.  The actinic ray-sensitive or radiation-sensitive resin com› position according to the present invention may be used for  negative development ( development where the exposed area  remains as a pattern and the unexposed area is removed) or  25  may be used for positive development ( development where  the exposed area is removed and the unexposed area remains  as a pattern). That is, the actinic ray-sensitive or radiation› sensitive resin composition according to the present invention  may be an actinic ray-sensitive or radiation-sensitive resin  composition for organic solvent development, which is used  for development using an organic solvent-containing devel› oper, or may be an actinic ray-sensitive or radiation-sensitive  resin composition for alkali development, which is used for  development using an alkali developer. Here, the term "for 35  organic solvent development" means usage where the com› position is subjected to at least a step of performing develop› ment by using an organic solvent-containing developer, and  the term "for alkali development" means usage where the  composition is subjected to at least a step of performing  development by using an alkali developer.  The actinic ray-sensitive or radiation-sensitive resin com› position of the present invention is typically a resist compo› sition and is preferably a negative resist composition (that is,  a resist composition for organic solvent development),  because particularly high effects can be obtained. Also, the  composition according to the present invention is typically a  chemical amplification resist composition.  The actinic ray-sensitive or radiation-sensitive resin com› position of the present invention ensures, at the formation of  a fine isolated pattern with a narrow line width (for example,  a line width on the order of several tens of nm), excellent  resolution, low PEB temperature dependency, rectangular  pattern profile, and high sensitivity and etching resistance.  The reason therefor is not clearly known but is presumed as  follows.  The repeating unit represented by formula (A) has an aro› matic ring group, and thanks to this configuration, the etching  resistance is considered to be increased. Also, although the  reason is not clearly known, it is believed that since the resin  (P) contains a repeating unit represented by formula (A), the  sensitivity is elevated. Furthermore, the repeating unit repre› sented by formula (A) has a specific hydroxyl group, and this  configuration is considered to bring about an increase in the  adherence to substrate and in turn, prevent an isolated pattern  from generation of pattern collapse, resulting in enhanced  resolution and a rectangular pattern profile.  The decomposition reaction of the repeating unit with an  acetal protection of carboxylic acid represented by formula  (1 ), which is induced by the action of an acid, has an appro› priate activation energy (Ea), and this is considered to allow  for appropriate control of the decomposition induced by the  action of an acid and bring about reduction in the PEB tem› perature dependency.  [1] (P) Resin  The resin (P) contains a repeating unit represented by the  following formula (1):  In formula (1 ), each ofR’ and Li independently represents  a hydrogen atom, an alkyl group, a cycloalkyl group, a halo› gen atom, a cyano group or an alkoxycarbonyl group. Li may  combine with L to form a ring and in this case, Li represents  a single bond, an alkylene group or a carbonyl group.  L represents a single bond or a divalent linking group, and  in the case of forming a ring together with Li, L represents a  trivalent linking group.  Each of Ria, Ri$_{6 }$and Ric independently represents an alkyl  group, a cycloalkyl group, an aryl group, an aralkyl group or  a heterocyclic group.  At least two of Ria, Ri$_{6 }$ and Ric may combine with each  other to form a ring, or at least one of Ria, Ri$_{6 }$ and Ric may  combine with R$_{2 }$ to form a ring.  R$_{2 }$ represents an alkyl group or a cycloalkyl group.  R$_{3 }$ represents a hydrogen atom or an alkyl group.  The alkyl group ofR’ and Li in formula (1) is preferably an  alkyl group having a carbon number of 20 or less, such as  methyl group, ethyl group, propyl group, isopropyl group,  n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl  group, octyl group and dodecyl group, which may have a  substituent, more preferably an alkyl group having a carbon  number of 8 or less, still more preferably an alkyl group  having a carbon number of 3 or less.  As the alkyl group contained in the alkoxycarbonyl group,  the same as the alkyl group in R’ and Li is preferred.  The cycloalkyl group may be either monocyclic or poly› cyclic and is preferably a monocyclic cycloalkyl group hav› ing a carbon number of 3 to 8, such as cyclopropyl group,  cyclopentyl group and cyclohexyl group, which may have a  substituent.  The halogen atom includes fluorine atom, chlorine atom,  bromine atom and iodine atom, with fluorine atom being  preferred.  Preferred examples of the substituent on the groups above  include an alkyl group, a cycloalkyl group, an aryl group, an  amino group, an amido group, a ureido group, a urethane  group, a hydroxyl group, a carboxyl group, a halogen atom,  an alkoxy group, a thioether group, an acyl group, an acyloxy  group, an alkoxycarbonyl group, a cyano group, and a nitro  group. The carbon number of the substituent is preferably 8 or  less.  (1) 