| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrapure water making apparatus for removing a cause factor present in ultrapure water resulting in the formation of a natural oxide film on the surface of a silicon wafer. SOLUTION: By an ultrapure water making apparatus arranged so as to obtain ultrapure water by passing primary pure water through an ultraviolet oxidizing device 26 capable of emitting at least ultraviolet rays having a wavelength in the vicinity of 185 nm, an oxidizable substance decomposing device 27 packed with a synthetic carbonaceous granular adsorbent, a membrane type degassing device 50 and a non-reproduction type ion exchange device 28 in this order, ultrapure water extremely low in the concns. of hydrogen peroxide and disolved oxygen can be obtained and, for example, the formation of a natural oxide film on the surface of a silicon wafer can be suppressed. |
