US 9,423,690 B2  4  3  (1-0)  (1-2)  wherein in Formula (1-0),  Ra represents a hydrogen atom, an alkyl group, a cyano  group or a halogen atom, and  L$_{1 }$ represents a single bond or  a divalent linking group,  in Formula  (1-2),  Rb represents a hydrogen atom, an alkyl group, a cyano  group or a halogen atom,  R$_{3 }$ represents a substituent,  n$_{1 }$ represents an integer of 1 or 2, n$_{2 }$ represents an integer  of Oto 4,  R$_{1 }$ and R$_{2 }$ each independently represent an alkyl group,  Ru and R$_{12 }$each independently represent an alkyl group,  R$_{13 }$ represents a hydrogen atom or an alkyl group,  Ru and R$_{12 }$may be bound with each other to form a ring,  and Ru and R$_{13 }$ may be bound with each other to form a  ring,  when n$_{2 }$ represents an integer of 2 to 4, R$_{3 }$’s may be bound  with each other to form a ring, and  L$_{2 }$ represents a single bond, --COO- or ----CONR$_{4}$-,  and R$_{4 }$ represents a hydrogen atom or an alkyl group.  [2] The pattern forming method according to [1],  wherein the repeating unit represented by Formula (1-0)  is a repeating unit represented by Formula (1-1):  (1-1)  wherein in Formula (1-1),  X represents an alicyclic group,  R$_{1 }$ and R$_{2 }$ each independently represent an alkyl group,  Ra represents a hydrogen atom, an alkyl group, a cyano  group or a halogen atom, and  wherein in Formula (2),  L$_{3 }$ and  L$_{4 }$ each independently represent a single bond or  a divalent linking group,  Y represents an atomic group capable of forming a lactone  structure, and  Re represents a hydrogen atom, an alkyl group, a cyano  group or a halogen atom.  [9] The pattern forming method according to any one of  [1]  to [8],  wherein the electron beam-sensitive or extreme ultravio- let ray-sensitive resin composition further contains a com› pound (B) capable of generating an acid upon the irradiation  with an electron beam or extreme ultraviolet, and  L$_{1 }$ represents a single bond or a divalent linking group.  [3] The pattern forming method according to [2],  wherein  X in Formula (1-1) is a cyclohexyl group or a  cyclopentyl group.  [4] The pattern forming method according to any one of  [1] to [3],  wherein the content of the repeating unit represented by  Formula  (1-0) or (1-1) is 55 mo! % or more based on the  whole repeating units in the resin  (A).  [5] The pattern forming method according to any one of  [1] to [4],  wherein a content of the repeating unit represented by  Formula  (1-2) is 15 mo! % or more based on the whole  repeating units in the resin (A).  [ 6] The pattern forming method according to any one of  [1] to [5],  wherein both of R$_{1 }$ and R$_{2 }$ in Formula (1-0) or (1-1) are  an alkyl group having 2 to 10 carbon atoms.  [7] The pattern forming method according to [6],  wherein both of R$_{1 }$ and R$_{2 }$ in Formula (1-0) or (1-1) are  an ethyl group.  [8] The pattern forming method according to any one of  [1] to [7],  wherein the resin  (A) further contains a repeating unit  represented by Formula  (2),  the content of the repeating unit represented by Formula  (1-0) or (1-1) is 45 to 85 mo!% based on the whole repeating  units in the resin  (A),  a content of the repeating unit represented by Formula  (1-2) is 15 to 45 mo!% based on the whole repeating units  in the resin  (A), and  a content of the repeating unit represented by Formula  (2)  is 1 to 40 mo! % based on the whole repeating units in the  resin  (A):  (2) 