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NR: not resolved 

As apparent from Table 2 above, in Comparative Examples 1-1 and 1-2 using Resins C-1 and C-2 (corre› sponding to Polymers A-4 and A-8 described in JP-A-8- 101507), Comparative Example 1-5 using Resin C-5 (cor› responding to the polymer of Example 11 described in JP-A-2000-29215), and Comparative Example 1-6 using Resin C-6 (corresponding to Resin (Al-1) described in JP-A-2010-217784), the sensitivity, resolution and space width roughness performance in the isolated space pattern formation were poor. This is considered to result because the resin does not contain a repeating unit having an acid› decomposable group with an acetal protection of carboxylic acid or even if the repeating unit is contained, the molar proportion thereof is less than 35 mo! %. 

In Comparative Examples 1-3 and 1-4 using Resins C-3 and C-4 (corresponding to PolymersA-1 andA-10 described in JP-A-8-101507), an isolated space pattern could not be resolved and also, the sensitivity and space width roughness could not be measured. This is considered to result because the resin containing a hydroxystyrene repeating unit having a methyl group on the a-position readily undergoes depo- lymerization and is unstable or the resin containing an acrylic acid repeating unit having an acid-decomposable group with an acetal protection is low in the Tg and allows for easy diffusion of the generated acid and for such a reason, an isolated space pattern could not be resolved. 

On the other hand, in Examples 1-1 to 1-59, an isolated space pattern could be formed with high sensitivity, high resolution and excellent space width roughness perfor› mance, as compared with Comparative Examples 1-1 to 1-6. 

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This is considered to occur because in the resin (A) for use in the present invention, the repeating unit with an acetal protection of carboxylic acid represented by formula (1-1) is low in the deprotection activation energy (Ea) and the molar proportion thereof is 35 mo! % or more, leading to high sensitivity and high contrast, as a result, high resolution and excellent space width roughness performance could be obtained. 

Incidentally, the same excellent results as in Examples above are obtained also in the case of not performing the rinsing step. 

## Examples 2-1 to 2-59 and Comparative Examples 2-1 to 2-5 

## Electron Beam (EB) Exposure, Positive Development with an Aqueous Alkali Solution, Evaluation of Isolated Space 

(4) Preparation of an actinic ray-sensitive or radiation› sensitive resin composition, pattern formation and evalua› tion of resist pattern were performed in the same manner as in Examples 1-1 to 1-59 and Comparative Examples 1-1 to 1-6 except that the resist film was irradiated with an electron beam by inverting the lithography region, the development was performed using an aqueous alkali solution (TMAH; an aqueous 2.38 mass % tetramethylammonium hydroxide solution) in place of the organic developer, and the rinsing solution was changed to water. 

