MKS 253B Series Exhaust Throttle Valve: 253B-31797 / 253B-26766 / 750B11TCB2GA —

Technical Dossier

Product Details And Specifications

MKS Instruments 253B Series: Comprehensive Module Range and Technical Overview

The MKS Instruments 253B Series is a line of motorized exhaust throttle valves engineered for precise pressure control in high-vacuum and process-critical environments. Deployed globally across semiconductor fabrication, chemical vapor deposition (CVD), dry etching, flat panel display manufacturing, and industrial vacuum furnace operations, the 253B platform is a standard component in process chambers requiring repeatable, low-particulate throttle control. Installations span facilities operated by leading chipmakers in the United States, South Korea, Japan, Taiwan, and Europe, as well as petrochemical and nuclear-adjacent industrial sites where process gas management demands sub-Torr precision.

The 253B series interfaces directly with MKS Type 651 and 252 pressure controllers, forming a closed-loop pressure regulation system. Its butterfly-valve architecture, combined with a stepper-motor actuator, delivers angular positioning resolution sufficient for sub-1% full-scale pressure repeatability. The series covers nominal bore sizes from 40 mm to 320 mm, accommodating a wide range of pumping speeds and chamber volumes.

The Evolution of 253B Architecture

MKS Instruments introduced the 253 series throttle valve platform in the early 1990s as a direct response to the semiconductor industry's transition to 200 mm wafer processing, which demanded tighter chamber pressure uniformity than manual gate valves could provide. The original 253 used a DC servo motor actuator with analog position feedback. By the mid-1990s, the 253A revision introduced improved shaft sealing and an upgraded encoder for finer angular resolution.

The 253B generation, released in the late 1990s and refined through the 2000s, replaced the DC servo with a stepper-motor drive, eliminating the need for a separate encoder and reducing the component count in the actuator assembly. The 253B also introduced a standardized 15-pin D-sub interface compatible with the MKS 651C/651E controller family, simplifying system integration. Variants within the 253B line differ primarily in bore diameter, body material (anodized aluminum vs. stainless steel), seal material (Viton vs. Kalrez for aggressive chemistries), and actuator torque rating.

As 300 mm wafer fabs became dominant through the 2000s and 2010s, MKS introduced the 253E and later the 253F series with enhanced particulate performance and faster slew rates. The 253B series is now in the mature/end-of-life phase for new equipment builds; however, it remains the installed base standard in a large number of legacy 200 mm tools still in production. Long-term maintenance support, including refurbished actuator assemblies and replacement seal kits, remains commercially available through authorized distributors and specialist spare-parts suppliers.

253B Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly encountered part numbers within the MKS 253B exhaust throttle valve series. Each entry includes the primary functional descriptor.

253B-31797: 253B throttle valve body assembly, 160 mm bore, anodized aluminum, Viton seal, stepper actuator — primary SKU.
253B-26766: 253B throttle valve assembly, alternate revision level, cross-referenced with 253B-31797 for compatibility verification.
750B11TCB2GA: MKS actuator/valve integrated assembly, stepper-motor driven, 15-pin D-sub interface, compatible with 651C/651E controllers.
253B-40160: 253B series, 40 mm bore, aluminum body, Viton O-ring, low-conductance configuration for small-volume chambers.
253B-80160: 253B series, 80 mm bore, standard aluminum body, general-purpose CVD and etch chamber throttle control.
253B-100160: 253B series, 100 mm bore, anodized aluminum, Viton seal, mid-range pumping speed compatibility.
253B-160160: 253B series, 160 mm bore, standard configuration, widely used in 200 mm etch and deposition tools.
253B-200160: 253B series, 200 mm bore, high-conductance variant for large-volume process chambers.
253B-250160: 253B series, 250 mm bore, aluminum body, suited for high-throughput CVD reactors.
253B-320160: 253B series, 320 mm bore, maximum conductance variant, used in large-format industrial vacuum systems.
253B-160260: 253B series, 160 mm bore, stainless steel body, Kalrez seal, corrosive-process chemistry variant (HF, Cl₂ compatible).
253B-200260: 253B series, 200 mm bore, stainless steel body, Kalrez seal, aggressive-chemistry high-conductance variant.
253B-160360: 253B series, 160 mm bore, high-torque actuator upgrade, for applications with elevated differential pressure across valve.
253B-100260: 253B series, 100 mm bore, stainless steel body, Kalrez seal, corrosive-chemistry mid-range variant.
253B-80260: 253B series, 80 mm bore, stainless steel body, Kalrez seal, small-chamber corrosive-process variant.
253B-40260: 253B series, 40 mm bore, stainless steel body, Kalrez seal, minimum-bore corrosive-chemistry configuration.
253B-160460: 253B series, 160 mm bore, heated-body option, prevents condensation of process by-products on valve interior surfaces.

Sourcing Hard-to-Find & Obsolete 253B Parts

The MKS 253B series has entered end-of-life status for new OEM procurement through standard distribution channels. MKS Instruments no longer manufactures the 253B actuator sub-assembly as a new-build item; replacement units are sourced through refurbishment programs or the secondary market. DriveKNMS maintains a dedicated inventory of 253B valve bodies, actuator assemblies, seal kits, and complete integrated units sourced from decommissioned equipment, factory overstock, and certified refurbishment pipelines.

For facilities operating legacy 200 mm semiconductor tools — including Applied Materials P5000, Lam Research 4500, Novellus Concept One, and equivalent platforms — where the 253B is the OEM-specified throttle valve, DriveKNMS provides lifecycle extension support including: direct part number cross-referencing, functional testing prior to shipment, and documentation of test results. Customers requiring long-lead or discontinued sub-components such as the stepper motor cartridge, position sensor board, or valve shaft seal assembly are encouraged to submit a detailed parts list for availability assessment.

Quality Control for the 253B Range

Each 253B unit processed by DriveKNMS undergoes a structured inspection and functional verification protocol prior to dispatch. The valve body is inspected for bore surface condition, seal groove integrity, and flange face flatness. The actuator assembly is bench-tested for full angular travel (0°–90°), step accuracy, and holding torque. The 15-pin D-sub interface is verified for pin continuity and correct signal mapping against the MKS 651-series controller pinout specification.

For units intended for corrosive-chemistry service (stainless/Kalrez variants), additional leak-down testing is performed at the shaft seal and body O-ring interfaces using a helium mass spectrometer leak detector to a sensitivity of 1×10⁻⁹ atm·cc/sec. Refurbished actuator cartridges are run-in on a dedicated test stand for a minimum of 500 full-stroke cycles before acceptance. All test data is retained and available to customers upon request.