| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter and a producing method thereof which suitably enhances a processing speed of separation without lowering the accuracy of separation. SOLUTION: An anodic oxide film 11 having a plurality of through-holes 12 and wall holes 14 is formed and then, at first, openings of the surface O side on arbitrary through-holes 12 among the plurality of through-holes 12 are clogged by coating films 15 (First clogging process). At this time, a coating solution 22 which forms coating films 15 is sprayed over the surface O of the anodic oxide film 11 from the position which is apart from by a prescribed distance L (Spraying process). Grain sizes of droplets 24 which are atomized by the spraying are screened and, at the same time, the droplets 24 are attached to the anodic oxide film 11 (Screening process). Then, ozone and TEOS are allowed to react with each other in the vicinity of opening end on the back surface R side in the through-holes 12 which are different from the arbitrary through-holes 12, silica 16 is deposited and, thereby, the openings on the back surface R side of the through-holes 12 are clogged (Second clogging process).
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