content_image/899149.jpg content_image/899148.jpg
<img src='content_image/899149.jpg'>

[4] Compound (D) Containing Phenolic Hydroxyl Group 

It is preferred for the composition of the present invention in its one form to comprise a compound (D) containing a phenolic hydroxyl group (hereinafter also referred to as compound (D)). 

The term "phenolic hydroxyl group" used in the present invention refers to a group resulting from the replacement of a hydrogen atom of an aromatic ring group by a hydroxyl group. The aromatic ring in the aromatic ring group is a mono- or polycyclic aromatic ring. As the aromatic ring, there can be mentioned a benzene ring, a naphthalene ring or the like. 

In the composition of the present invention comprising compound (D), at exposed areas, a crosslinking reaction between compound (D) containing a phenolic hydroxyl group and the above-mentioned compound (C) containing an acid-crosslinkable group progresses under the action of an acid generated from acid generator (B) upon exposure to actinic rays or radiation, thereby forming a negative pattern. In particular, when acid generator (B) produces an acid with a structure in which two or more methylol groups are contained in its molecule, not only the crosslinking reaction between compound (D) and compound (C) but also the contribution of a plurality of methylol groups contained in acid generator (B) to the crosslinking reaction can further enhance the dry etching resistance, sensitivity and resolving power. 

Compound (D) containing a phenolic hydroxyl group is not particularly limited as long as a phenolic hydroxyl group is contained. It may be a relatively low molecular com› pound, such as a molecular resist, and may be a polymeric compound. As the molecular resist, use can be made of, for example, any of low-molecular-weight cyclic polyphenol compounds described in JP-A’s 2009-173623 and 2009- 173625. 

It is preferred for compound (D) containing a phenolic hydroxyl group to be a polymeric compound from the viewpoint of reactivity and sensitivity. 

When compound (D) containing a phenolic hydroxyl group according to the present invention is a polymeric compound, the polymeric compound comprises a repeating unit containing at least one phenolic hydroxyl group. The repeating unit containing a phenolic hydroxyl group is not 

-continued 

particularly limited, which is however preferably any of repeating units of general formula (II) below. 

In the formula, 

R$_{2 }$ represents a hydrogen atom, an optionally substituted methyl group or a halogen atom; 

B’ represents a single bond or a bivalent connecting group; 

Ar’ represents an aromatic ring group; and 

m is an integer of 1 or greater. 

As the optionally substituted methyl group represented by R$_{2}$ , there can be mentioned a trifluoromethyl group, a hydroxymethyl group or the like. 

R$_{2 }$ is preferably a hydrogen atom or a methyl group. A hydrogen atom is more preferred from the viewpoint of developability. 

The bivalent connecting group represented by B’ is pref- erably a carbonyl group, an alkylene group (preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms), a sulfonyl group (-S(=O)$_{2}$ -), ---0-, -NH-, or a bivalent connecting group comprised of a combination of these. 

B’ is more preferably a single bond, a carbonyloxy group (-C(=O)-O-) or-C(=O)-NH-, further more pref› erably a single bond or a carbonyloxy group (----C(=O)› O-). A single bond is most preferred from the viewpoint of dry etching resistance. 

The aromatic ring represented by Ar’ is a monocyclic or polycyclic aromatic ring. As such, there can be mentioned an optionally substituted aromatic hydrocarbon ring having 6 to 18 carbon atoms, such as a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring or a phenanthrene ring, or an aromatic ring heterocycle containing a heteroring, such as a thiophene ring, a furan ring, a pyrrole ring, a benzothio- phene ring, a benzofuran ring, a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazole ring, a triazole ring, a thiadiazole ring or a triazole ring. Of these, a benzene ring and a naphthalene ring are preferred from the viewpoint of resolution. A benzene ring is most preferred from the view- point of sensitivity. 

In the formula, m is preferably an integer of 1 to 5, most preferably 1. When m is 1 and Ar’ is a benzene ring, the position of-OH substitution may be any of the para-, meta› and ortho-positions to the site of bonding to B’ (when B’ is a single bond, the principal chain of the polymer) in the benzene ring. However, from the viewpoint of crosslinking reactivity, the para- and meta-positions are preferred, and the para-position is more preferred. 

A substituent other than the above -OH group may be introduced in the aromatic ring represented by Ar’. As such a substituent, there can be mentioned, for example, an alkyl group, a cycloalkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbo› nyl group, an alkylcarbonyl group, an alkylcarbonyloxy group, an alkylsulfonyloxy group or an arylcarbonyl group. 

<img src='content_image/899148.jpg'>

