To provide an actinic ray-sensitive or radiation-sensitive resin composition which resolves on a vertical sidewall in forming a contact hole pattern, ensures enhanced EDW, improves side lobe resistance, and reduced the number of Blob defects, as well as a resist film and a pattern formation method using the composition. コンタクトホールパターン形成時に垂直な側壁にて解像し、広いEDWを確保でき、サイドローブ耐性が良化し、かつBlob欠陥数が低減した感活性光線性又は感放射線性樹脂組成物、並びにそれを用いたレジスト膜及びパターン形成方法を提供する。 - 特許庁