US 2019/0196326 Al  27  Jun.27,2019  (Al)  [0206]  Each of the above groups may have a substituent,  examples of the substituent include an alkyl group (having  [0205]  It is preferable that the repeating unit represented  by Formula (AI), for example, is an aspect in which Rx$_{1 }$ is  a methyl group or an ethyl group, and in which and  Rx$_{2 }$ and  Rx$_{3 }$ are bonded to each other to form the above cycloalkyl  group.  [0191]  The resin (A) preferably has a repeating unit hav› ing an acid-decomposable group as described above. A  repeating unit that has acid-decomposable group is prefer› ably a repeating unit represented by Formula (AI).  [0190]  Hereinafter, the resin (A) is described in detail.  [0189]  Examples of the alkali-soluble group include a  carboxy group, a fluorinated alcohol group (preferably a  hexafluoroisopropanol group), and a sulfonic acid group.  [0204]  With respect to the cycloalkyl group formed by  bonding two of Rx$_{1 }$ to Rx$_{3}$ ,  for example, one of the meth› ylene groups constituting the ring may be substituted with a  hetero atom such as an oxygen atom or a group having a  hetero atom such as a carbonyl group.  [0203]  The cycloalkyl group formed by bonding two of  Rx$_{1 }$to Rx$_{3 }$ is preferably a monocyclic cycloalkyl group such  as a cyclopentyl group and a cyclohexyl group or a poly› cyclic cycloalkyl group such as a norbornyl group, a tetra› cyclodecanyl group, a tetracyclododecanyl group, or an  adamantyl group. The monocyclic cycloalkyl group having  5 to 6 carbon atoms is more preferable.  [0202]  The cycloalkyl group of Rx$_{1 }$ to Rx$_{3 }$ is preferably a  monocyclic cycloalkyl group such as a cyclopentyl group or  a cyclohexyl group, a polycyclic cycloalkyl group such as a  norbornyl group, a tetracyclodecanyl group, a tetracyclodo› decanyl group, or an adamantyl group.  [0201]  The alkyl group of Rx$_{1 }$ to Rx$_{3 }$ preferably has 1 to  4 carbon atoms.  [0200]  preferably a single bond or a -COO-Rt- group.  Rt is preferably an alkylene group having 1 to 5 carbon  atoms and more preferably a ----CH$_{2}$ - group, a -(CH$_{2}$ ) 2 - group, and a -(CH$_{2}$ ) 3 - group.  [0199]  Examples of the divalent linking group ofT include  an alkylene group, a --COO-Rt- group, and an -O-Rt› group. In the formula, Rt represents an alkylene group or a  cycloalkylene group.  [0188]  Among these, the resin (A) is more preferably a  resin (Al) that is decomposed due to an action of an acid to  increase polarity. That is, the resin (A) is a resin in which  solubility in an alkali developer increases due to an action of  an acid, or solubility in a developer with an organic solvent  as a main component due to an action of an acid decreases,  and specifically, a resin having a group (hereinafter also  referred to as an "acid-decomposable group") that generates  an alkali-soluble group by being decomposed due to an  action of an acid on at least one of a main chain or a side  chain.  [0187]  As the resin, it is possible to use a well-known resin  that can form a resist pattern but a resin (hereinafter, referred  to as a "resin (A)") in which polarity changes due to an  action of an acid is preferable.  [0186]  The act1mc ray-sensitive or radiation-sensitive  resin composition according to the embodiment of the  present invention contains a resin.  [0198]  According to an aspect, Xa$_{1 }$ is preferably a hydro› gen atom, a methyl group, a trifluoromethyl group, or a  hydroxymethyl group  [0197]  Examples of the alkyl group that is represented by  Xa$_{1 }$ and may have a substituent include a methyl group and  a group represented by ----CH$_{2}$-R$_{11}$ . R $_{11 }$represents a halo› gen atom (such as a fluorine atom), a hydroxyl group, or a  monovalent organic group.  [0196]  Two of Rx$_{1 }$ to Rx$_{3 }$ are bonded to form a (mono› cyclic or polycyclic) cycloalkyl group.  [0185]  In the acid generator, the compound that generates  the acid represented by Formula  (I)  due to the irradiation of  an actinic ray or radiation and another acid generator may be  used together, but the content of the compound that gener› ates the acid represented by Formula  (I)  due to the irradia› tion of an actinic ray or radiation is preferably 50 mass % or  more, more preferably 85 mass % or more, even more  preferably  90 mass % or more, and particularly preferably  95 mass% or more with respect to a total mass of the used  acid generator.  [0184]  In a case where the actinic ray-sensitive or radia› tion-sensitive resin composition according to the embodi› ment of the present invention contains two or more kinds of  acid generators, a total content of the acid generator is  preferably in the above range.  [0195]  Rx$_{1 }$ to Rx$_{3 }$ each independently represent a (linear  or branched) alkyl group or a (monocyclic or polycyclic)  cycloalkyl group.  [0194]  T represents a single bond or a divalent linking  group.  [0193]  Xa$_{1 }$ represents a hydrogen atom or an alkyl group  that may have a substituent.  [0192]  In Formula (AI),  [0183]  By causing the content of the acid generator to be  in this range, the exposure margin in a case where the resist  pattern is formed is improved.  [0182]  The content of the acid generator in the actinic  ray-sensitive  or  radiation-sensitive  resin  composition  according to the embodiment of the present invention is  preferably 0.1 to 20 mass%, more preferably 0.5 to 20 mass  %, and even more preferably 5 to 20 mass % with respect to  the total solid content of the actinic ray-sensitive or radia› tion-sensitive resin composition.  to the irradiation with an actinic ray or radiation used in a  micro resist or the like can be appropriately selected to be  used.  Resin  Repeating Unit Having Acid-Decomposable Group 