Ultrafacility 2025 Roundtable Insights: Managing Purity in High-Purity Chemical and Water Infrastructure

At Ultrafacility 2025, Electrochemical (ECM) hosted a roundtable titled “Products and Services for the Handling of High-Purity Chemicals, Including Water.” The discussion focused on material selection, fabrication challenges, and system-level requirements for the safe storage and transport of high-purity chemicals and ultrapure water used in semiconductor manufacturing.

ECM, a provider of fluoropolymer-lined steel vessels, was joined by its sister company Superior Dual Laminate Products (SDL), which supplies dual laminate and FRP vessels and piping systems. Both companies operate under Knight Material Technologies (KMT). 

Michael Krauss shared perspectives on why the topic is increasingly important and highlighted key themes that emerged during the discussion.

Why purity management is becoming more critical

As semiconductor devices continue to scale in accordance with Moore’s Law, contamination control requirements have intensified. Where the industry once focused primarily on physical particles larger than two nanometres, even particle precursors are now recognised as a potential risk. As a result, meeting ever-tightening customer purity specifications has become progressively more challenging.

Materials selection trade-offs for high purity environments

Concerns over metal ion contamination have driven the gradual elimination of many metallic alloys from chemical and ultrapure water systems, increasing reliance on polymer-based materials. PVDF has a long track record in ultrapure water storage and transport, while PFA is widely used for its chemical resistance and low levels of leachables and extractables. 

From a manufacturing perspective, materials selection is often a balancing act. A material that meets purity requirements may not be compatible with lining processes or long-term service life, while alternatives that perform well from a fabrication standpoint may fall short on purity. In semiconductor applications, this balance is particularly difficult, as materials must meet simultaneous demands for ultra-low contamination, corrosion resistance, and mechanical performance.

For example, solid PVDF is widely used in fab water lines because of its low leachables, temperature tolerance, and mechanical strength. However, those same mechanical properties can create stress issues when used as a liner, leading manufacturers to consider more flexible PVDF grades or alternative materials such as PFA. As a result, materials selection must be evaluated on a case-by-case basis.

Limitations of current testing and qualification practices

One question raised during the roundtable discussion was whether it is possible to quantify the purity of equipment during or after fabrication. While lining materials may be verified against standards such as SEMI F57, vessels are not typically tested in service. The challenge is that extractables are influenced by the entire system, not just the tank. It includes filtration, recirculation, operating conditions, and residence time, so it is hard to get a representative test.

Additional challenges arise because standards such as SEMI F57 are based on piping systems rather than tanks. Differences in flow rates and surface-to-volume ratios mean that a material may not meet piping-based criteria but still be suitable for tank applications. Accelerating updates to SEMI standards to reflect these differences would benefit the industry.

Post-fabrication testing as an emerging concept

The possibility of testing leachables and extractables after fabrication of lined tanks was discussed at the roundtable as an emerging concept. Unlike solid PVDF piping systems, which are manufactured in cleanroom environments with minimal human contact, lined tanks require significantly more hands-on fabrication. Workers may enter large steel vessels to weld liners, making cleanliness more difficult to control.

The idea would be to test tanks after fabrication and cleaning to establish a quantifiable baseline for extractables. Feasibility, however, remains a separate consideration. The acquisition of specialised equipment is being explored; however, this presents challenges because the data obtained from testing does not necessarily reflect conditions in the field, which may in fact be cleaner than the test results indicate. What is required is a system that can deliver reproducible results, providing clients with a clear and reliable level of confidence that the tank is clean.

Identifying contamination across complex supply chains

A key industry challenge is the increasing complexity of bulk chemical and water systems, particularly when storage, transport, and recycling are involved. Ensuring that every component in that chain meets end-user requirements is becoming more difficult as systems grow larger and more interconnected.

Maintaining the purity levels expected by end users is not just about the storage tank itself. Contamination can be introduced at multiple stages, from chemical production and transfer into transport containers, through logistics, and finally into on-site bulk storage. By the time the material is tested at the point of use, identifying where contaminants were introduced and how to correct the issue can be extremely challenging.

Improving alignment with end-user requirements

A clear theme from the discussion was the importance of communication. Semiconductor producers are placing increasingly demanding requirements on suppliers, but those expectations are not always clearly communicated across the supply chain.

There are a lot of silos. If we are quoting a bulk storage tank, we may be talking to a systems integrator, and they are working with an end-user, and sometimes there is another intermediary stage in between. As a result, enquiries may arrive without clear specifications for extractables or purity targets, and there may be little opportunity for suppliers to explain what levels of performance are realistically achievable. 

So, improving transparency and communication around requirements, constraints, and trade-offs will be essential as purity demands continue to rise and systems become more complex.

This was one of many insightful technical roundtable discussions at the conference. For further perspectives, see this session hosted by H2O Innovation; Ultrafacility 2025 Roundtable Summary: Enabling Growth Through On-Site Water Reclamation and Reuse | Insights | UltraFacility