63  US 9,958,775 B2  64  which is capable of decomposing by the action of an acid  (hereinafter, also referred as a "compound (B2)").  The compound (B2) is preferably insoluble or slightly  soluble to an alkali developer.  The compound (B2) is preferably a resin having a repeat- ing unit having a group which is capable of decomposing by  the action of an acid (hereinafter, also referred as an "acid› decomposable group").  Examples of the acid-decomposable group include a  group in which a hydrogen atom of an alkali-soluble group  such as a carboxyl group, a phenolic hydroxyl group, a  sulfonic acid group, and a thiol group is protected with a  group leaving by the action of an acid.  Examples of the group leaving by the action of an acid  include  ----C(R 36 )(R 37 )(R 38 ),  -C(R 36 )(R 37 )(OR 39 ),  ----C(=O)---O-C(R36)(R37)(R3s),  -CCR01)(Ro2)(OR39),  ----C(R 01 )(R 02 )-C(=O)---0-C(R 36 )(R 37 )(R 38 ), and the  like.  In the formulae, R 36  to R 39  each independently represent  an alkyl group, a cycloalkyl group, an aryl group, an aralkyl  group, or an alkenyl group. R 36  and R 37  may be bonded to  each other to form a ring. R 01  to R 02  each independently  represent a hydrogen atom, an alkyl group, a cycloalkyl  group, an aryl group, an aralkyl group, or an alkenyl group.  In one embodiment, the compound (B2) preferably  includes a repeating unit represented by the following gen› eral formula (AI) as a repeating unit having an acid-decom› posable group.  [Chem. 36]  (Al)  In the formula, L 1  to L$_{5 }$ each independently represent a  hydrogen atom, a hydroxymethyl group, a methoxymethyl  group, an ethoxymethyl group, or an alkyl group having 1 to  6  carbon atoms.  The cross-linking agent in the present invention is pref› erably from 3 to 65% by mass and more preferably from 5  to 50% by mass in the total solid contents of the composition  for negative-tone pattern formation. When the content rate  of the cross-linking agent is set to the range of 3 to 65% by  mass, decreases in the residual film ratio and resolving  power are prevented, and the stability upon storage of the  composition in the present invention can be satisfactorily  maintained.  In the present invention, the cross-linking agent (C) may  be used alone, or two or more kinds may be used in  combination. From the viewpoint of an excellent pattern  shape, it is preferable to use two or more kinds in combi- nation.  For example, in a case where the other cross-linking  agent, for example, the compound having an N-alkoxym› ethyl group described before, is used in combination with  the phenol derivative described above, the proportion of the  phenol derivative and the other cross-linking agent is, as a  molar ratio, usually from 90/10 to 20/80, preferably from  85/15 to 40/60, and more preferably from 80/20 to 50/50.  [4] Compound Having a Group which is Capable of  Decomposing by the Action of an Acid (B2)  In one embodiment, the composition according to the  present invention includes a compound having a group  In the general formula (AI),  Xa 1  represents a hydrogen atom, a methyl group or a  group represented by ----CH 2 -R 9 . R 9  represents a  hydroxyl group or a monovalent organic group, for  example, includes an alkyl group having 5 or less  carbon atoms or an acyl group, is preferably an alkyl  group having  3  or less carbon atoms and more prefer- ably a methyl group. Xa 1  is preferably a hydrogen  atom, a methyl group, a trifluoromethyl group, or a  hydroxymethyl group;  T represents a single bond or a divalent linking group;  Rx 1  to Rx 3  each independently represent an alkyl group  (linear or branched) or a cycloalkyl group (monocyclic  or polycyclic); and  At least two of Rx 1  to Rx 3  may be bonded to each other  to form a cycloalkyl group (monocyclic or polycyclic).  Examples of the divalent linking group of T include an  alkylene group, -COO-Rt-group, ---0-Rt-group, and the  like. In the formulae, Rt represents an alkylene group or a  cycloalkylene group.  The alkyl group ofRx 1  to Rx 3  is preferably an alkyl group  having 1 to 4 carbon atoms such as a methyl group, an ethyl  T is preferably a single bond or -COO-Rt-group. Rt is  preferably an alkylene group having 1 to 5 carbon atoms and  $^{more preferably -CH}$2- group, or -(CH 2 ) 3 - group.  OH  OH  OH  -continued 