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(3) A Functional Group Containing the Structure in which Two Atoms Different in Electronegativity by 0.5 or More are Bonded by a Double Bond or a Triple Bond 

As such a polar group, a group containing the structure represented, for example, by C N, C=O, N=O, S=O or C N is exemplified. 

( 4) A Functional Group Having an Ionic Site 

As such a polar group, a group having the site represented, for example, by N+ or s+ is exemplified. 

The specific examples of partial structures that "polar group" can contain are shown below. 

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"Polar group" that repeating unit (b) can contain is prefer- ably at least one selected from the group consisting of (I) a hydroxyl group, (II) a cyano group, (III) a lactone group, (IV) a carboxylic acid group or a sulfonic acid group, (V) an amido group, a sulfonamide group, or a group corresponding to the derivative thereof, (VI) an ammonium group or a sulfonium group, and a group obtained by combining two or more of these groups. 

When a repeating unit having a cyano group is further added to the resin, the sensitivity of a composition containing the resin can be further improved. 

When a repeating unit having a lactone group is further added to the resin, dissolution contrast in a developer con› taining an organic solvent can be further improved, by which it also becomes possible to further improve the dry etching resistance, coating stability and adhering property to sub› strate of the composition containing the resin. 

When a repeating unit having a group containing a lactone structure having a cyano group is further added to the resin, dissolution contrast in a developer containing an organic sol› vent can be further improved, by which it also becomes pos- sible to further improve the sensitivity, dry etching resistance, coating stability and adhering property to substrate of the composition containing the resin. In addition to the above, it is possible for a single repeating unit to bear functions result› ing from each of the cyano group and the lactone group, thus the degree of freedom of design of the resin can further be increased. 

When the polar group that repeating unit (b) has is an alcoholic hydroxyl group, repeating unit (b) is preferably represented by at least one formula selected from the group consisting of the following formulae (I-1 H) to (I-1 OH), more preferably represented by at least one formula selected from the group consisting of formulae (I-lH) to (I-3H), and still more preferably represented by formulae (I-lH). 

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