This guide recommends the water quality required for the electronics and microelectronics industries. High-purity water is required to prevent contamination of products during manufacture, since contamination can lead to an unacceptable, low yield of electronic devices.
The range of water purity is defined in accordance with the manufacturing process. The types of ultra-pure water are defined with respect to device line width. In all cases, the water-quality recommendations apply at the point of distribution.
The limits on the impurities are related to current contamination specifications and to available analytical methods (either performed in a suitable clean laboratory or by on-line instrumentation). On-line and off-line methods are used in accordance with current industry practice. Concentration of the sample may be required to measure the impurities at the levels indicated in Table 1.
TABLE 1 Requirements for Water at the Point of Distribution in the Electronics and Semiconductor IndustriesA
| Parameter | Type E-1 | Type E-1.1 | Type E-1.2B | Type E-1.3B | Type E-2 | Type E-3 | Type E-4 |
|---|---|---|---|---|---|---|---|
| Linewidth (microns) | 1.0–0.5 | 0.35–0.25 | 0.18–0.09 | 0.065–0.032 | 5.0–1.0 | >5.0 | |
| Resistivity, 25°C (On-line) | 18.1 | 18.2 | 18.2 | 18.2 | 16.5 | 12 | 0.5 |
| TOC (μg/L) (on-line for <10 ppb) | 5 | 2 | 1 | 1 | 50 | 300 | 1000 |
| On-line dissolved oxygen (μg/L) | 25 | 10 | 3 | 10 | |||
| On-Line Residue after evaporation (μg/L) | 1 | 0.5 | 0.1 |