US 2012/0003590 Al  2  Jan. 5, 2012  [0014]  R$_{1 }$ represents a hydrogen atom, an alkyl group, a  cycloalkyl group, a halogen atom, a cyano group or an alky› loxycarbonyl group.  [2] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in [ 1] above, in formula (I), Rn and  AR are combined with each other to form a non-aromatic  ring.  [3] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in [1] or [2] above, the repeating  unit (A) represented by formula (I) contains two or more  aromatic rings.  [ 4] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in any one of [1] to [3] above, AR in  formula (I) contains two or more aromatic rings.  [5] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in any of [1] to [ 4] above, the  repeating unit (B) is at least one selected from the group  consisting of repeating units represented by the following  formulae (Bl), (B2) and (B3):  cycloalkyl group, an alkenyl group, a cycloakenyl group, an  aryl group or an aralkyl group.  [6] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in  [5] above, the A is an ionic structural moiety having a sulfo› nium salt structure or an iodonium salt structure.  [7] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in any of[l] to [6], the resin further  contains at least either one of a repeating unit represented by  the following formula (Al) and a repeating unit represented  by formula (A2):  [0019]  wherein in formula (A 1),  [0021]  n represents an integer of 1 to 5 satisfying the rela› tionship ofm+m~15,  [0020]  m represents an integer of  O  to 4,  [0022]  S$_{1 }$ represents a substituent (excluding hydrogen  atom) and when m~2, each S$_{1 }$may be the same as or different  from every other S $_{1}$ ,  and  [0023]  A$_{1 }$represents a hydrogen atom or a group capable of  leaving by the action of an acid and when n~2, eachA$_{1 }$ may  be the same as or different from every other A$_{1}$ ;  and  [0024]  in formula (A2),  [0025]  X represents a hydrogen atom, an alkyl group, a  hydroxyl group, an alkoxy group, a halogen atom, a cyano  group, a nitro group, an acyl group, an acyloxy group, a  cycloalkyl group, a cycloalkyloxy group, an aryl group, a  carboxy group, an alkyloxycarbonyl group, an alkylcarbony› loxy group or an aralkyl group, and  [0026]  A$_{2 }$ represents a group capable of leaving by the  action of an acid.  [0015]  wherein A represents a structural moiety capable of  decomposing upon irradiation with an actinic ray or radiation  to generate an acid anion,  [0016]  each ofR$_{04}$, R$_{05 }$and R$_{07 }$to R$_{09 }$independently rep› resents a hydrogen atom, an alkyl group, a cycloalkyl group,  a cyano group or an alkoxycarbonyl group,  [0017]  R$_{06 }$ represents a cyano group, a carboxy group,  -CO-OR$_{25 }$ or ----CO-N(R$_{26}$)(R$_{27}$), R 25  represents an  alkyl group, a cycloalkyl group, an alkenyl group, a cycloalk› enyl group, an aryl group or an aralkyl group, R$_{26 }$and R$_{27 }$ may combine with each other to form a ring together with the  nitrogen atom, each of R$_{26 }$and R$_{27 }$independently represents  a hydrogen atom, an alkyl group, a cycloalkyl group, an  alkenyl group, a cycloalkenyl group, an aryl group or an  aralkyl group,  [0018]  each ofX$_{1 }$ to X$_{3 }$ independently represents a single  bond, an arylene group, an alkylene group, a cycloalkylene  group,  -0-,  -S0$_{2}$ -,  -CO-, -N(R$_{33}$)-or a divalent  linking group formed by combining a plurality of these mem› bers, and R$_{33 }$represents a hydrogen atom, an alkyl group, a  [8] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in any one of [1] to [7] above, the  actinic ray-sensitive or radiation-sensitive resin composition  is for a KrF excimer laser, an electron beam, an X-ray or EUV  light.  [9] A resist film is formed using the actinic ray-sensitive or  radiation-sensitive resin composition described in any of [1]  to [8] above.  [10] A pattern forming method comprises exposing and  developing the resist film described in [9] above.  [0027]  The present invention preferably further includes  the following configurations.  [11] In the actinic ray-sensitive or radiation-sensitive resin  composition as described in any one of [1] to [8] above, the  weight average molecular weight of the resin is from 1,000 to  200,000.  (Bl)  (B2)  Ros  Ro1  I  I  *--+C-C+--*  I  I  Ro6  X2  I  A  (B3)  (Al)  (A2) 