US 2017 /0059990 Al  56  Mar. 2, 2017  [0286]  Here, the low-molecular compound (B) means a  compound other than a compound in which a part that  generates an acid by irradiation with actinic rays or radiation  is introduced into a main chain or a side chain of a resin, and  is typically a compound in which the part is introduced into  a monomolecular compound. The molecular weight of the  low-molecular compound (B) is generally 4,000 or less,  preferably 2,000 or less, and more preferably 1,000 or less.  In addition, the molecular weight of the low-molecular  compound (B) is generally 100 or greater, and preferably  200 or greater.  [0287]  As a preferred embodiment of the acid generator  (B), an onium compound can be exemplified. Examples of  such an acid generator (B) include a sulfonium salt, an  iodonium salt, and a phosphonium salt.  [0288]  As another preferred embodiment of the acid gen› erator (B), a compound that generates a sulfonic acid, an  imido acid, or a methide acid by irradiation with actinic rays  or radiation can be exemplified. Examples of the acid  generator (B) of the embodiment include a sulfonium salt, an  iodonium salt, a phosphonium salt, oxime sulfonate, and  imido sulfonate.  [0289]  The acid generator (B) is preferably a compound  that generates an acid by irradiation with electron beams or  extreme ultraviolet rays, and more preferably a compound  that generates an acid by electron beams.  [0290]  The radiation-sensitive or actinic ray-sensitive  resin composition of the invention may not contain the acid  generator (B). However, in a case where the radiation› sensitive or actinic ray-sensitive resin composition contains  the acid generator (B), the content of the acid generator (B)  is preferably 0.1 to 30 mass %, more preferably 0.5 to 20  mass%, and even more preferably 1.0 to 10 mass% based  on the total solid content of the radiation-sensitive or actinic  ray-sensitive resin composition.  [0291]  The acid generators (B) can be used alone or in  combination of two or more kinds thereof.  [0292]  Specific examples of the acid generator (B) of the  invention are as follows.  (zl)  (z3)  (z6)  (z7)  (z9)  (zll)  (  Oti-0-0-ifO),  ,  o,s*c  F  F  (zlO)  (zS)  (z5)  (z4)  (  ens, O;S  3  (z2) 