Ultrapure Water (UPW) Systems: 18.2 MΩ·cm, ASTM D1193 Type I
Ultrapure water solutions with a resistivity of 18.2 MΩ·cm for microchip, semiconductor and high-technology R&D laboratories.
What Is Ultrapure Water (UPW)?
Ultrapure Water (UPW) is, in theory, the highest purity level that water can have (18.2 MΩ·cm resistivity). In water at this level, contaminants such as ions, organic matter, bacteria, endotoxins, gases and particles are far below analytical limits. It is used especially in the semiconductor industry, electronics manufacturing, solar panel production and sensitive analytical laboratories.
Advanced Treatment Technologies
Advanced contaminant removal processes.
Purification Steps
- Advanced membrane process: Excellent primary ion removal with double-pass reverse osmosis (Double Pass RO).
- Polishing: 18.2 MΩ·cm quality with Ionpure CEDI modules and specific mixed-bed polishing resins.
- TOC oxidation: Breaking of organic carbon bonds with Nuvonic 185 nm UV lamps, bringing the TOC level below ≤50 ppb.
- Final filtration: Retention of the finest particles and bacteria with ultrafiltration (UF) membranes rated 0.05 µm (and finer).
Materials and Piping
- Piping: Fully welded, high-purity PVDF (polyvinylidene fluoride) piping systems in place of 316L stainless steel, to prevent metal ion release.
- Connections: All-welded distribution networks aimed at zero particle generation.
- Instrumentation: Sensitive online sensors for trace-level TOC and particle measurement.
UPW Quality Standards
| Parameter | ASTM D1193 Type I | ISO 3696 Grade 1 | SEMI F63 (Typical Targets) |
|---|---|---|---|
| Resistivity (@25°C) | 18.0 MΩ·cm (Conductivity: ≤0.056 µS/cm) | 10.0 MΩ·cm (Conductivity: ≤0.1 µS/cm) | 18.1 - 18.2 MΩ·cm |
| TOC (Total Organic Carbon) | ≤50 ppb | N/A (suitable method) | < 1 ppb (Critical lines) |
| Sodium / Chloride | ≤1 ppb | - | < 0.01 ppb (Critical lines) |
| Bacteria / Endotoxin | Bacteria < 10 CFU/1000 mL, Endotoxin < 0.03 EU/mL | - | Practically none |
| Particles | - | - | Strict particle counting (e.g. >0.05µm) |
Industry Applications
Semiconductor
Water with near-zero particle, organic and inorganic contamination to SEMI F63 norms in microchip and wafer manufacturing (washing and rinsing processes).
Electronics and Solar
Deionized water that leaves no residue in surface treatment and washing of solar panels, printed circuit boards (PCB) and sensitive electronic components.
Pharmaceutical R&D
Use of Type I and Grade 1 water for mobile phase preparation in advanced analytical instruments such as HPLC and GC-MS in drug development and analytical laboratories.
Frequently Asked Questions about Ultrapure Water (UPW) Systems
Common questions about ultrapure water quality criteria, treatment steps and applications.
What is ultrapure water (UPW)?
Ultrapure water is water with extremely low ion, organic matter, particle and bacteria content and a resistivity of ≥ 18 MΩ·cm (typically 18.2 MΩ·cm at 25 °C). It is defined by the ASTM D1193 Type I and ISO 3696 Grade 1 standards.
What is the conductivity value of ultrapure water?
Ultrapure water is expressed by resistivity (MΩ·cm) rather than conductivity; the two values are the inverse of each other. At 25 °C, resistivity for ASTM D1193 Type I is 18.0 MΩ·cm, i.e. conductivity ≤ 0.056 µS/cm; for ISO 3696 Grade 1 it is 10.0 MΩ·cm, i.e. ≤ 0.1 µS/cm. In semiconductor lines (SEMI F63) the target is 18.1-18.2 MΩ·cm.
What is the difference between ultrapure water and purified water (PW)?
Purified water (PW) meets conductivity ≤ 1.3 µS/cm and TOC ≤ 500 ppb limits and is intended for pharmaceutical applications. Ultrapure water has a resistivity of ≥ 18 MΩ·cm, requires TOC at low ppb levels and final filtration at 0.22 µm or finer, and is intended for laboratory analytics and electronics processes.
Which applications use ultrapure water?
It is used in laboratory analytics such as HPLC, ICP-MS and molecular biology, in semiconductor and microelectronics manufacturing (ASTM D5127) and in high-technology R&D processes.
What treatment steps does an ultrapure water system consist of?
A typical UPW system consists of pre-treatment (softening, activated carbon), reverse osmosis (RO), electrodeionization (EDI), TOC reduction with 185 nm UV, ion exchange polishing and finally membrane filtration at 0.22 µm or finer.
Which standards define ultrapure water quality?
ASTM D1193 (Type I-IV reagent water grades), ISO 3696 (analytical laboratory water Grades 1-3) and ASTM D5127 (guide for UPW in the electronics and semiconductor industries) are the main reference standards.
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