US 9,557,643 B2  4  3  (2) a step of exposing the film by using an actinic ray or  radiation, and  (4) a step of developing the exposed film by using an  organic solvent-containing developer to form a negative  pattern.  [2] The pattern forming method as described in [1],  wherein the  (C) compound capable of decomposing by  the action of an acid to generate an acid is a compound  represented by any one of the following formulae (1) to (8):  Ry$_{2 }$ represents an aryl group or an aryloxy group, and  X represents  -SO$_{2}$ -,  -SO- or --CO-;  in formula (2),  Ri’ represents an alkyl group, a cycloalkyl group, an  alkoxy group, an aryl group or an aryloxy group,  R$_{2}$ ’  represents an alkyl group or a cycloalkyl group,  Ri’ and R$_{2}$ ’  may combine to form a monocyclic or  polycyclic cyclic hydrocarbon structure,  each of R$_{3}$’ and R$_{4}$’ independently represents a hydrogen  atom or an alkyl group,  Rs’ represents an aryl group-free group capable ofleaving  by the action of an acid, and  X’ represents -SO$_{2}$ -,  -SO- or -CO-;  in formulae (3) to (6),  Rb represents an alkyl group, a cycloalkyl group, an aryl  group or an aralkyl group,  R$_{7 }$ represents a hydrogen atom, an alkyl group, a  cycloalkyl group, an aryl group or an aralkyl group,  Rs represents an alkyl group, a cycloalkyl group, an aryl  group or an aralkyl group,  R$_{9 }$ represents a hydrogen atom, an alkyl group, a  cycloalkyl group, an aryl group or an aralkyl group,  R$_{9 }$ may combine with R$_{7 }$ to form a ring,  R$_{10 }$ represents an alkyl group, a cycloalkyl group, an  alkoxy group, an aryl group, an aralkyl group, an aryloxy  group or an alkenyloxy group,  Ru represents an alkyl group, a cycloalkyl group, an  alkoxy group, an aryl group, an aralkyl group, an aryloxy  group or an alkenyl group,  R$_{10 }$and Ru may combine with each other to form a ring,  and  R$_{12 }$represents an alkyl group, a cycloalkyl group, an aryl  group, an alkenyl group, an alkynyl group or a cyclic imide  group;  in formulae (7) and (8),  each of R$_{13 }$to R$_{16 }$and R$_{19 }$to R$_{23 }$ represents a hydrogen  atom or a monovalent substituent,  each of R$_{17 }$and R$_{1}$s represents a monovalent substituent,  and R$_{1 7 }$ and R$_{1}$s may combine with each other to form a ring;  and  in formulae (1) to (5), (7) and (8),  each of  Zi, Zi’, Z$_{3}$ ,  Z$_{4}$ ,  Zs,  Z$_{7 }$ and Zs is independently a  group represented by any one of the following formulae  (Z-a) to (Z-d), and each  Zs  may be the same as or different  from every other Zs:  R,-x-+-1-o-t’,,  R3+Ri  H  Z1  Formula (1)  R2’  0  R1’-X’~O-Rs’  R/+Ri’  Z1’  Formula (2)  Formula (3)  0  II  R10-C-C=C-R11  H  I  Z4  Formula (4)  Formula (5)  Formula (6)  R13  R1s  R16  Z1  I  I  I  0-Ris  R14 H  0  I  Rn  Formula (8)  R19  R21  R23  Zs  I  I  I  OH  R20 H  R22  wherein in formula (1 ),  R$_{1 }$ represents an alkyl group, a cycloalkyl group, an  alkoxy group, an aryl group or an aryloxy group,  R$_{2 }$ represents an alkyl group or a cycloalkyl group,  R$_{1 }$ and R$_{2 }$ may combine to form a monocyclic or poly› cyclic cyclic hydrocarbon structure,  each of R$_{3 }$ and R$_{4 }$ independently represents a hydrogen  atom or an alkyl group,  Ry $_{1 }$ represents a hydrogen atom, an alkyl group, a 65  cycloalkyl group, an alkoxy group, an aryl group, or an  alkylene group combining with Ry$_{2}$ ,  wherein in formulae (Z-a) to (Z-d),  each ofRb$_{1 }$ and Rb$_{2 }$ independently represents an organic  group,  each of Rb$_{3}$ ,  Rb$_{4 }$ and Rbs independently represents an  organic group, and  Rb$_{3 }$ and Rb$_{4 }$ may combine to form a ring.  (Z-a)  (Z-b)  (Z-c)  (Z-d) 