The Performance Comparison of Ultrapure Water TOC Analyzers using an Automated Standard Addition Apparatus

摘要

Improvements in ultrapure water technology have driven the typical level of TOC in semiconductor process water to less than 5 ppb. The performance of commercially available TOC analyzers at these low levels of TOC has never been characterized. It is not known how well low level on-line TOC analyzers can measure the likely organic compounds that may be found in UPW. We have applied an on-line standard addition apparatus in a field study of UPW systems to answer these questions. The details of this apparatus were discussed in the 1999 SPWCC. Four different ultrapure water TOC analyzers, Anatel A1000, Anatel A1000XP, Sievers Model PPT, and the Thornton 502P were studied. When very low levels of dissolved oxygen or high levels of dissolved hydrogen were present in the tested UPW, a Sievers 800, with internal oxidizer addition, was used to assure the accuracy of the standard additions. Nine organic compounds were selected based on the likelihood of their presence in UPW or their chemical similarities to compounds that are likely to be present in UPW. The compounds studied included trimethylamine (anion resin), benzenesulfonic acid (cation resin), IPA (source water and bacterial metabolic waste), urea (source water), sucrose (small easy to oxidize organic), glycidol (reclaim water), TMAH (reclaim water), 1,3-dichloro 2-propanol (analog for chloroform), chloroform, and mixtures of these organic compounds. The study was conducted at five different semiconductor sites. The UPW sources at these sites varied in dissolved oxygen levels from 25 ppb to zero ppb. One site had high levels of residual H_2 in solution. The water and ambient temperatures at the sites were about 25 degrees °C, one site temperature water and ambient temperature was 32 °C. The data from these tests are examined and compared. The surprising results of the study are discussed and analyzed.