The Role of High-Purity Piping in Semiconductor Manufacturing

Semiconductors are created when gases and liquids spark chemical reactions that deposit or etch away material from thin, high-crystalline wafers. Wafers are then washed with ultra-clean water to dissolve residual debris. The contamination of any of these fluid sources can trigger unwanted reactions and destroy hundreds of thousands of dollars worth of chips. This makes the clean delivery of chemicals through high-purity piping a critical, yet easily overlooked component of semiconductor fabrication.

Preserving Purity

Even small, trace amounts of metallic ions, moisture, and environmental particles can deal irreversible damage to thousands of wafers. Even worse, impurities can damage equipment and indefinitely shut down production while management procures replacements. Fortunately, engineers have developed piping made of high-purity materials that resist corrosion and the buildup of residue. 

The task of preserving purity falls on more than just engineers. The technicians installing the piping must adhere to stringent protocols and a rigorous quality assurance/quality control (QA/QC) process.

Material Selection

The most common materials used for high-purity piping are fluoropolymers like PVDF and PFA, traditional 316L stainless steel, and steels that have undergone electropolishing. 

Fluorolymers are mainly used to transport abrasive, corrosive chemicals like solvents and acids because it is chemically stable and has smooth internal sources that reduce particle adhesion. 

316L stainless steel is mainly used to transport ultra-pure water, since it has traces of molybdenum (typically 2% to 3%) to reduce chloride corrosion and lower carbon content to reduce carbide precipitation during welding.

316L stainless steel can undergo electropolishing (EP) to enhance its smoothness and resistance to corrosion. However, the process itself is expensive and requires considerable time. 

Orbital Welding

Traditional welding is imprecise and can create small imperfections like surface crevices or internal sugaring from uneven heat application. This, in turn, causes small amounts of corrosion and flaking that are acceptable for most industrial applications but are disastrous for semiconductor fabrication. 

Instead, semiconductor technicians must use orbital welding to minimize imperfections. In orbital welding, a machine runs a preset computer program to rotate a welding head 360 degrees around a pipe with a fixed diameter. This greatly minimizes human error and increases the precision and uniformity of the weld. 

However, automation is no excuse for carelessness. Technicians must carefully clean pipe ends to prepare for welding, record the pipes during welding, and examine piping and the video itself after welding. These inspections may require the use of a borescope to check for discolorations and pressurization tests to monitor gas leakage. 

Conclusion

High-purity piping may be hidden behind walls and ceilings, but it’s one of the most essential systems in any fab. Poorly executed piping can compromise entire production lines, while expertly installed systems ensure maximum yield, uptime, and product quality. 

BBTech America’s tool hookup teams are trained to meet high-purity standards and approach each installation process with precision. Together we combine decades of experience with state-of-the-art tools to deliver flawless results, no matter the situation.