Semiconductor ultrapure water systems

Figure 2.6 schematically illustrates sections of a typical semiconductor ultrapure water (UPW) production process in a semiconductor plant. The water circuit consists of two main sections (1) makeup (or central) system and (2) polishing loop, which provides water at the point of use. There are multiple locations in such a water process where membrane degassing could be needed as shown in the figure. Reverse osmosis is mostly used in makeup line as the primary purification means in such processes. In the past, large and inflexible vacuum towers were frequently used after RO to remove dissolved gases, such as O2, N2, and CO2. Membrane contactors are the norm today for replacement or supplement to vacuum towers in makeup lines, as shown in Figure 2.6. 

Figure 3.45 Process flow schematic of a typical ultrapure water system used in semiconductor manufacturing (5.0-mm cartridge filter upstream of RO pump not shown).

SEMI (2001) Guide for Ultrapure Water System Used in Semiconductor Processing, SEMI F61, SEMI, San Jose. 

Membrane-based technologies have become the industry standard for the ultrapure water systems in the semiconductor, pharmaceutical, and power industries. The seminal discovery that changed membrane separation from a laboratory to an industrial process was the development, in the early 1960s, of the Loeb-Sourtrajan process for making defect-free, high-flux, anisotropic reverse osmosis membranes (Loeb and Sourirajan, 1963). The most important development in the 1980s was the innovation of industrial membrane gas separation process. 

A typical ultrapure water system for the semiconductor industry is illustrated in Eigure 13.1. The reverse osmosis (RO)/electrodeionization (EDI) system is gaining more and more in importance in a typical UPW system due to its contamination-free design. 

Figure 13.1 Typical ultrapure water system in the semiconductor industry.

Motomura, Y. Yabe, K. Piping materials and distribution systems for advanced ultrapure water. Proceedings of Tenth Annual Semiconductor Pure Water Conference, Santa Clara, CA, 1991, 1-22. 

N. Urai, System for ultrapure water production and waste water treatment in semiconductor factory, Denshi Zairyou (Electric Parts and Materials), 2002, 41(8), 43-48 M. Tamura, Development of hybridized desalination unit, D2EDI, Zousui Gijutus (J. Water Re-use Technol.), 2003, 28, 30-33. 

The purified water system is designed to supply 16 trf/h ultrapure water (UPW) to a semiconductor plant. Typical treatment steps follow the sequence given below, not all of which are shown in Figure 5.3 ... 

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