Method for producing composition for forming coating film for lithography and patterning process

A patterning process comprising the steps of:

• producing a composition using a producing apparatus provided with a metal adsorbent, a stirrer, and a filter, the producing process comprises:
• introducing a solvent into the producing apparatus,
• circulating the solvent in the producing apparatus so that a metal impurity is adsorbed by the metal adsorbent,
• adding a raw material of the composition into the circulated solvent and homogenizing the raw material of the composition by stirring the mixture containing the raw material and the circulated solvent with the stirrer to prepare the composition, and
• circulating the prepared composition in the producing apparatus so that a microscopic foreign matter is removed by the filter to form a filtrated composition,
• forming an organic under layer film on a body to be processed,
• forming a silicon-containing resist under layer film on the organic under layer film,
• forming a resist pattern on the silicon-containing resist under layer film,
• transferring a pattern to the silicon-containing resist under layer film by dry etching using the resist pattern as an etching mask,
• transferring the pattern to the organic under layer film by dry etching using the silicon-containing resist under layer film having the transferred pattern as an etching mask, and
• transferring the pattern to the body to be processed by dry etching using the organic under layer film having the transferred pattern as an etching mask,
• wherein one or more of the organic under layer film, the silicon-containing resist under layer film, and a resist upper layer film is/are formed from the filtrated composition.