Semiconductor Fab Gas Delivery
Semiconductor fabrication uses more specialty gases than almost any other industry, and each one reaches the tool through a chain of valves. From the cylinder cabinet through the valve manifold box to the point-of-use isolation at the process chamber, every valve must protect purity, prove its position and close safely on an interlock.
Contamination at the parts-per-billion level can change film properties or kill a wafer lot. That is why fab gas systems standardise on UHP diaphragm valves with electropolished wetted surfaces, VCR face seal connections and helium leak certification.
Gases and valve requirements
Silane, dichlorosilane, ammonia, nitrogen trifluoride, hydrogen chloride, chlorine, arsine and phosphine place very different demands on wetted materials. Pyrophoric and toxic gases require normally closed pneumatic valves with proven safe state; corrosive halides require compatible diaphragm alloys.
- Deposition: SiH4, DCS, NH3, NF3
- Etch: Cl2, HCl, HBr, NF3
- Dopants: AsH3, PH3, B2H6 in carrier gas
- Bulk: N2, Ar, He, H2, O2
From gas yard to point of use
A typical path is cylinder valve, high pressure isolation, two stage regulator, VMB process/purge valves, distribution header, VMP branch valves and finally a point-of-use UHP diaphragm valve at the tool. Check valves protect each branch against reverse migration.
- Cylinder and regulator at the gas yard
- VMB with purge and vent interlocks
- VMP branch distribution
- Point-of-use UHP diaphragm isolation
Qualification and documentation
Fab projects usually require helium leak test records, material traceability, surface finish data and cleanroom packaging evidence. Collecting these per valve, rather than per panel, simplifies tool qualification and later expansion.
- Helium leak records per valve
- Material and surface finish certificates
- Cleanroom double-bag packaging
Recommended valve families
UHP Diaphragm Valves
Ultra high purity diaphragm valves for specialty gas delivery. 316L VIM/VAR bodies
Pneumatic Diaphragm Valves
Air-actuated UHP diaphragm valves for automated gas panels and VMB/VMP systems. Normally closed
Gas Valve Manifolds & VMB
Specialty gas valve manifold boxes, valve manifold panels and automatic changeover systems built
Frequently Asked Questions
Which valve type is standard for fab UHP lines?
A normally closed pneumatic UHP diaphragm valve with VCR face seal ends is the standard; manual valves are used for maintenance isolation.
Why are face seal connections preferred?
They give a repeatable metal-to-metal seal with minimal dead volume and can be re-made without disturbing welded headers.