71  US 9,323,150 B2  72  -continued  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:  (4) film thinning (selections of hydrophilicity/hydropho› bicity and alkali-soluble group),  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.  (1) solubility in application solvents,  (2) film forming easiness (glass transition point),  (3) alkali developability,  (5) adhesion of unexposed area to substrate,  (6) dry etching resistance, etc.  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).  Ra  ~  Ra  ~  0 