The Cost of Inaccuracy at Semiconductor Fabricators

If the reading goes below 18.00 MΩ-cm, you need to shut down the water system to prevent yield loss. The resistivity sensor you are using has a 1% accuracy specification, which is very common in the marketplace but double that of a UPW UniCond. Let’s see how the UPW UniCond’s much tighter specification of 0.5% offers greater protection in terms of preventing expensive shutdowns and even more expensive impacts to yield.

After one full day, the investigation concludes that there was no problem with the water system. The water quality was 18.15 MΩ-cm, but the resistivity reading at 17.96 MΩ-cm—within specification of the resistivity sensor—was false (see Figure 2). That false reading and your resulting shutdown cost your company $1.2 million.

If you had used a UPW UniCond sensor, this scenario would have been avoided. With a 0.5% accuracy specification, the UPW UniCond would not display 18.15 MΩ-cm water as out of tolerance. In short, UPW UniCond helps to protect your yield and the water system from unexpected, costly shutdowns.

As a water system owner, how should you interpret the resistivity readings? Should you read it as 18.12 MΩ-cm or 18.14 MΩ-cm? The UPW UniCond reads 18.19 MΩ-cm consistently in this test, leaving no room for error.

As specifications for semiconductor fabrication are becoming increasingly strict, analytics must keep pace. Because analytics monitor product worth millions of dollars, only the most reliable analytics should be considered.