Polymer for chemically amplified resist and chemically amplified resist composition containing the same

The present invention relates to a polymer with increased adhesion to substrate and a resist composition containing the same. More particularly, the present invention relates to a novel polymer that is useful for preparation of a photoresist suitable for fine works using various radiations, such as KrF or ArF excimer laser, X-rays such as synchrotron radiation, and charged particle rays such as electron beam, and a resist composition containing the polymer. Disclosed is a polymer for use in a chemically amplified resist, a resist composition including such a polymer is suitable for use in a chemically amplified resist, which is sensitive to KrF or ArF excimer laser and forms a photoresist pattern having low dependence on and good adhesion to substrate, high transparency in the wavelength range of the above radiation, strong resistance to dry etching, and excellencies in sensitivity, resolution and developability. The resist composition can have a stronger etching resistance with a maximized content of unsaturated aliphatic ring in the polymer and a reduced edge roughness of the photoresist pattern with an alkoxyalkyl acrylate monomer employed.