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The resin (Aa) according to the present invention can con› tain, in addition to the foregoing repeating structural units, various repeating structural units for the purpose of regulating the dry etching resistance, standard developer adaptability, substrate adhesion, resist profile and generally required prop› erties of the resist such as resolving power, heat resistance and sensitivity. 

As such repeating structural units, there can be mentioned those corresponding to the following monomers, which how› ever are nonlimiting. 

The use of such repeating structural units would allow fine regulation of the required properties of the resin for use in the composition of the present invention, especially: 

(1) solubility in application solvents, 

(2) film forming easiness (glass transition point), 

(3) alkali developability, 

(4) film thinning (selections of hydrophilicity/hydropho› bicity and alkali-soluble group), 

(5) adhesion of unexposed area to substrate, 

(6) dry etching resistance, etc. 

As appropriate monomers, there can be mentioned, for example, a compound having an unsaturated bond capable of addition polymerization, selected from among acrylic esters, methacrylic esters, acrylamides, methacrylamides, ally! com- pounds, vinyl ethers, vinyl esters, styrenes, crotonic esters and the like. As other compounds, there can be mentioned maleic anhydride, maleimide, acrylonitrile, methacrylonitrile and maleironitrile. 

In addition, any unsaturated compound capable of addition polymerization that is copolymerizable with monomers cor› responding to the above various repeating structural units may be copolymerized therewith. 

Nonlimiting preferred specific examples of the repeating 65 units derived from such other polymerizable monomers are shown below. 

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In the resin (P) for use in the composition of the present invention, the molar ratios of individual repeating structural units contained are appropriately determined from the view› point of regulation of not only the dry etching resistance of the resist but also the standard developer adaptability, substrate adhesion, resist profile and generally required properties of the resist such as the resolving power, heat resistance and sensitivity. 

The content of the repeating units having an acid-decom› posable group is preferably in the range of O to 95 mo! %, more preferably 10 to 60 mo! % and further more preferably 15 to 50 mo! %, based on all the repeating units of the resin (Aa). 

The content of the repeating units of general formula (Al) is preferably in the range of Oto 90 mo! %, more preferably 0 to 85 mo!% and further more preferably Oto 80 mo!%, based on all the repeating units of the resin (Aa). 

The content of the repeating units of general formula (A2) is preferably in the range of Oto 90 mo! %, more preferably 0 to 75 mo!% and further more preferably Oto 60 mo!%, based on all the repeating units of the resin (Aa). 

The content of the repeating units of general formula (A3) is preferably in the range of Oto 70 mo! %, more preferably 1 to 50 mo!% and further more preferably 5 to 40 mo!%, based on all the repeating units of the resin (Aa). 

The content of repeating unit expressed by general formula (A4) in the resin (Aa), based on all the repeating units of the resin, is preferably in the range of O to 50 mo! %, more preferably Oto 40 mo! % and most preferably Oto 30 mo! %. 

When the repeating unit containing a group that is decom› posed by the action of an alkali developer to thereby increase its rate of dissolution in the alkali developer is contained in the resin (Aa), the content of thereof, based on all the repeating units of the resin, is preferably in the range of0.5 to 80 mo!%, more preferably 1 to 60 mo! % and further more preferably 2 to 40mol %. 

The resin (Aa) may further have other repeating units. Preferred forms of the other repeating units are as follows: 

(cyl) repeating unit that contains a fluorine atom and/or a silicon atom, being stable in an acid and insoluble in an alkali developer, 

( cy2) repeating unit that contains neither a fluorine atom nor a silicon atom, being stable in an acid and insoluble in an alkali developer, 

(cy3) repeating unit that contains a fluorine atom and/or a silicon atom, having a polar group other than the aforemen› tioned groups (x) and (z), and 

(cy4) repeating unit that contains neither a fluorine atom nor a silicon atom, having a polar group other than the afore› mentioned groups (x) and (z). 

