Guides / Process

Machining Gas Delivery Components for Semiconductor Tools

September 21, 2026

Gas delivery hardware is the least forgiving machined part in a semiconductor tool. The critical surface is inside the part, where it cannot be inspected easily and the failure mode is a slow one: moisture, particles and contamination that show up as yield loss weeks later.

The part is the internal surface

On a chamber body the outside matters. On a manifold block the only surface that matters is the one the gas touches. That changes how the part is made:

• Internal passages are drilled and reamed, then deburred by a process that reaches inside the part, not by hand at the entry
• Cross drilled intersections are the hardest feature to deburr and the most common source of particles
• Electropolish is a bath process, so the passage has to be designed so the electrolyte reaches every wetted surface
• Blind holes and trapped volumes are designed out, because no finishing process fixes them

Gas wetted surfaces are commonly specified around 8 Ra microinch after electropolish. Smoother surfaces hold less moisture and release it faster, which is what a short purge time buys you.

What belongs on the drawing

Requirement	How to state it	Why
Material	316L with a lot certificate, melt practice if it matters	Traceability and corrosion behaviour
Internal finish	Ra maximum on gas wetted surfaces, with the surfaces named	Prevents a blanket spec on the whole part
Deburr	Method, not the word “deburr all edges”	Cross drills need a defined process
Cleaning	Cleaning standard and final rinse	The part is only as clean as the last step
Packing	Sealed, purged if required, double bagged	Protects the internal surface in transit
Tests	Leak rate and method, particle or moisture test if required	Defines pass and fail before the argument

Testing before it ships

For a gas stick or manifold the useful tests are a helium leak test at the rate your system needs, a moisture or purge down check when the application is sensitive and a visual or borescope check of the internal passages where the geometry allows it. Residual gas analysis is used on parts going into vacuum to show they will not contaminate the system. That subject is covered in outgassing and RGA testing.

Require the report, not a verbal pass. A test without a record cannot be audited later when the tool behaves oddly.

Where Vietnam shops sit on this work

Plenty of shops here can machine the block. Far fewer can control the whole chain: deburr inside the passages, get a repeatable electropolish result from a qualified finisher, clean the part without recontaminating it and pack it so the internal surface arrives as it left. That chain is the real capability question, and it is the one worth auditing before you place a first order. The questions to ask are in supplier audit questions.

If you need quotes for gas wetted hardware, send the RFQ with the internal finish and the test requirement stated and we will only match shops that have run that chain before.

Frequently asked questions

More on process

• Packing and Shipping Machined Parts to a Fab or Test Floor
• Weldments and Machine Frames for Tool Builders
• What Cleanroom Machining Actually Requires
• Test Handler Change Kits: What Buyers Should Specify

All guides and the sourcing glossary.