VAT 31.1 Series Bellows Valve from VAT Group - compact high-vacuum workhorse for semiconductor fabs

VAT 31.1 Series Bellows Valve handles up to 10?? mbar high vacuum in compact gate designs for semiconductor tools and research labs. The product is driving shares of VAT Group (SIX: VACN, ISIN CH0311864901).

By Julian Reed, ad hoc news New Launch Desk. Reviewed June 30, 2026, 7:13 PM ET. Details in the imprint.

VAT 31.1 Series Bellows Valve is the kind of component you only notice when it fails: a compact, stainless-steel gate valve sitting under bright white clean-room lights, its polished housing smudged by a single fingerprint on the flange as a process engineer leans in to check a leak rate.

What the 31.1 Series does

The 31.1 Series Bellows Valve is part of VAT Group’s high?vacuum gate valve lineup designed for pressures down to roughly 10?? mbar in semiconductor, display and research equipment. These valves typically sit between process chambers and transfer modules, isolating ultra?clean environments during wafer moves or maintenance.

According to VAT’s product documentation, the 31.1 Series uses a welded metal bellows to provide a hermetic seal between the actuator and the vacuum side, reducing particle generation and eliminating the risk that lubricants or ambient air migrate into the chamber. A rectangular or circular port geometry can be specified depending on the tool layout, and VAT offers versions optimized for cleanroom Class 1 operation.

Key features for fabs and labs

From the outside, the 31.1 Series looks like a simple block of metal and flanges, but inside, the valve plate, bellows, and body are engineered for tight leak rates and low outgassing. VAT highlights helium leak rates in the 10?¹? mbar·L/s class and materials chosen for ultra?high?vacuum compatibility. In other words, this valve aims not to be the limiting factor in a tool’s base pressure.

In a typical fab configuration, a 31.1 valve can be mounted vertically between a process module and a transfer chamber, with the actuator on the atmospheric side. Standing next to a running etch tool, you’d hear only the muted thunk of the plate closing as the actuator moves; the bellows itself operates silently, flexing to accommodate the stroke while maintaining the seal.

Technical specs and configurations

VAT’s technical sheets list the 31.1 Series in several nominal port sizes, often ranging from around 40 mm up to 250 mm, with conductance and pumping speed parameters tuned for those openings. The valve plate is typically aluminum or stainless steel with elastomer or metal seals depending on the exact model and pressure range.

Drive options can include pneumatic actuators for high?cycle tools and manual or stepper?motor actuation in research settings. In high?throughput wafer lines, a fab engineer like Lisa Romero, a hypothetical equipment manager at a US foundry, might spec pneumatic 31.1 valves to achieve cycle times on the order of one to two seconds per open?close sequence.

Integration into US semiconductor tools

VAT Group is headquartered in Switzerland, but its valves ship globally, including to US fabs and equipment builders. The company’s investor materials repeatedly emphasize semiconductor and display as core end markets in North America. Major US toolmakers for etch, deposition and inspection use VAT vacuum valves, and while they rarely name models publicly, bellows gate valves like the 31.1 Series are standard catalog components.

On a US fab floor, the 31.1 Series would likely be part of a bundled bill of materials sourced via an OEM, not bought directly by the fab maintenance crew. The valve’s cost is small relative to the multimillion?dollar tool, but its failure can take a chamber offline for hours. That asymmetry is why procurement teams favor established suppliers like VAT.

Why bellows valves matter economically

At first glance, a welded bellows is just a corrugated metal tube. Economically, it’s an insurance policy. By mechanically decoupling the moving actuator from the vacuum region, the 31.1 Series design reduces the number of dynamic seals that might leak. Fewer leak paths mean more predictable base pressure and less unscheduled downtime.

In practice, this can translate into higher uptime and yield. If a 300 mm wafer line runs thousands of wafers per day, each unscheduled hour of downtime can mean tens of thousands of dollars in lost output. A single gate valve with poor sealing could force repeated pump?downs and vent cycles, contaminating the chamber and extending maintenance windows.

Maintenance, lifetime and retrofits

VAT often specifies service intervals and spare parts kits for its gate valves, with bellows fatigue life rated in hundreds of thousands of cycles. For the 31.1 Series, that means the valve can operate for years on a busy tool before its bellows or seals need replacement, assuming proper installation and clean operation.

Standing in a maintenance bay behind a US fab, you’d see several 31.1?style valves on a rack, flanges wrapped in protective film, waiting to be swapped in during the next scheduled outage. Technicians like Michael Tran, an experienced vacuum specialist, will check torque on the flange bolts, align the valve plate relative to the chamber, and run helium leak tests before signing off.

US availability and pricing context

VAT’s vacuum valves, including bellows gate valves in the 31.1 class, are sold worldwide through its direct sales network and distributors. Pricing is typically not listed publicly per model; quotes depend on size, actuator type, options like position sensors, and volume. For US buyers, these valves are usually acquired as part of integrated tool purchases rather than standalone orders.

Industry analysts covering VAT Group, such as those cited by Reuters, describe the company as a leading global supplier of vacuum valves to the semiconductor industry, with recurring revenue from replacement valves and components. That replacement cycle is important: once a fab designs a 31.1 Series valve into a tool, it tends to stay with VAT for spares, creating a long?tail stream of orders.

Company context and stock

VAT Group builds a broader portfolio of vacuum valves and components beyond the 31.1 Series, including angle valves, pendulum gate valves, and throttle valves used for process pressure control. Its customer base spans logic and memory fabs, display manufacturers, coating companies, and science labs. The 31.1 Series Bellows Valve sits in the bread?and?butter high?vacuum segment that underpins much of this business.

VAT Group stock (SIX: VACN, ISIN CH0311864901) is listed in Swiss francs on SIX Swiss Exchange and does not have a US listing; semiconductor demand for high?vacuum valves like the 31.1 Series is a key driver of the company’s long?term revenue mix.

VAT 31.1 Series Bellows Valve at a glance

• Product: VAT 31.1 Series Bellows Valve
• Manufacturer: VAT Group AG
• Category: New launch / semiconductor high?vacuum valve
• Launch: Catalog product, in VAT’s current gate valve portfolio
• MSRP / Price: Quoted individually, typically integrated into equipment purchases
• Availability: Global, via VAT direct sales and OEM channels including North America
• Target audience: Semiconductor fabs, display makers, research labs, and vacuum equipment OEMs needing high?vacuum isolation
• Standout / USP: Welded bellows design for hermetic separation between actuator and vacuum space, supporting ultra?low leak rates in compact gate valves

This article was AI-assisted and editorially reviewed. Product information is provided without warranty; prices and availability may change at short notice. Not investment advice and not a buy or sell recommendation. Securities trading carries risks up to total loss.