Planarizing agent for forming organic film, composition for forming organic film, method for forming organic film, and patterning process

A composition for forming an organic film, comprising:

• a resin for forming an organic film;
• a planarizing agent for forming an organic film;
• and
• a solvent, wherein
• the resin for forming an organic film has at least one aromatic skeleton, wherein
• the planarizing agent for forming an organic film, consists of at least one aromatic-group-containing compound having a molecular weight represented by a molecular formula of 200 to 500, wherein
• the composition for forming an organic film is a blended composition formed by blending a preliminary composition containing the resin for forming an organic film and the solvent, with the planarizing agent for forming an organic film, wherein
• the preliminary composition has a complex viscosity of 1.0 Pa·3 s or more in a temperature range of 175° C. or higher, and
• the blended composition has a complex viscosity of less than 1.0 Pa·s in a temperature range of 175° C. or higher;
• and
• wherein the planarizing agent for forming an organic film is one or more compounds selected from the general formulae (I) or (II),
• wherein R1 each independently represents a hydrogen atom, a hydroxy group, or an optionally substituted organic group having 1 to 10 carbon atoms:
• W1 represents a phenylene group or a divalent group represented by the following general formula (I-1);
• W2 and W3 represent a single bond or any one divalent group represented by the following general formula (I-2);
• m1 represents an integer of 2 to 10:
• and n1 each independently represents an integer of 0 to 5;
• and when W2 and W3 are both carbonyl groups in the formula (I-2), W1 represents a phenylene group and m1 is 2 or 3,
• wherein “*” represents a bonding position;
• R10, R11, R12, and R13 represent a hydrogen atom, a hydroxy group, or an organic group having 1 to 10 carbon atoms;
• W10 and W11 each independently represent a single bond or a carbonyl group;
• m10 and m11 represent an integer of 0 to 10, and m10+m11≥1,
• wherein “*” represents a bonding position,
• wherein R2 each independently represents a hydrogen atom or an optionally substituted organic group having 1 to 10 carbon atoms;
• W4 represents a divalent group represented by the following general formula (II-1);
• W5 represents a single bond or any one divalent group represented by the following general formula (II-2);
• m2 represents an integer of 5 to 10;
• and n3 represents an integer of 0 to 5,
• wherein “*” represents a bonding position;
• R20, R21, R22, and R23 represent a hydrogen atom, a hydroxy group, or an organic group having 1 to 10 carbon atoms;
• m20 and m21 represent an integer of 0 to 10;
• and m20+m21≥ 1,
• wherein “** represents a bonding position.