Machined Parts for Semiconductor Equipment Suppliers

Machined parts for semiconductor equipment are chamber bodies, gas distribution blocks, wafer-handling components and frames, made from stainless steel and aluminium alloys. The difficulty sits in the specification around the metal: SEMI F19 and F20 for wetted stainless steel surfaces and material, ISO 14644-9 for particle cleanliness on surfaces, and individual tolerances, coatings and documents written on the drawing.

Which machined parts go into semiconductor equipment?

A tool builder or Tier 1 supplier in this field buys a small number of part families, each with its own failure mode. The table groups them by what the drawing has to add to the geometry. Builders of vacuum and semiconductor equipment usually split these families across different suppliers.

Table 1. Typical part groups and what the drawing must add

Source: SEMI F19-0815, SEMI F20-0923, ISO 10074:2021. The part groups are typical examples, not a complete list.

The vacuum side of chamber parts (pressure ranges, outgassing, bake-out) is covered in machined components for vacuum and cryogenic systems. This article covers what is specific to semiconductor equipment.

Which materials do the drawings call for?

For gas and liquid distribution components the drawing names 316L stainless steel to SEMI F20. SEMI F20-0923, listed as the current edition, defines metallurgical cleanliness requirements and composition for 316L bar, forgings, extruded shapes, plate and tubing, and refers to ASTM A276, A182, A240, A269 and A632 for the product forms. That goes beyond the grade: 1.4404 is the usual EN 10088 counterpart of 316L, but a drawing that needs SEMI F20 material has to say so, and the certificate has to refer to it. Grade differences are in stainless steel for machined parts.

Aluminium alloys serve chamber parts, liners, plates and handling components. The alloy designation, temper and product form belong on the drawing together with any anodizing standard, so that no substitution inside an alloy family happens without the buyer's knowledge.

What surface rules apply to wetted stainless steel parts?

SEMI F19-0815 sets quality requirements for the wetted surfaces of stainless steel components in semiconductor gas and liquid distribution systems. It was approved for publication on 19 May 2015, replaced SEMI F19-0304, and the SEMI store lists it as current. The standard defines surface characterization and finish acceptance criteria for tubing and components made to SEMI F20, and names the tests: roughness (SEMI F37), ESCA (F60), AES (F72), SEM (F73) and critical pitting temperature (F77).

Two practical consequences follow. First, the standard applies to wetted surfaces of distribution components, not to every face of every part, so the drawing marks which surfaces are wetted. Second, the numeric roughness limits sit in the paid standard, which is why a drawing should state the required Ra value and the measuring method itself instead of only citing the document.

How is the cleanliness of a machined part specified and checked?

Cleanroom class numbers describe air. ISO 14644-1:2015 specifies classes of air cleanliness as particles per volume of air, and says nothing about a part. For a surface, ISO 14644-9:2022 gives the assessment procedure. It covers walls, tools, equipment and products, and particles from 0.05 µm to 500 µm. The standard excludes cleaning procedures, process-specific cleanliness requirements and material characteristics, so a drawing that says only "ISO 14644-9" is incomplete.

State four things instead:

• the particle size and the permitted count per unit of surface, set by the equipment builder for the process;
• the test method and sampling position;
• the cleaning method, for which EN ISO 14644-13:2026 gives guidance, published in May 2026 as successor to the 2017 edition;
• the packaging and the point after which the part is not touched.

Residue from machining sets the starting condition for all of this. Cutting fluid, marker and chips go before precision cleaning, a point the vacuum article treats in detail. Our network machines by milling and turning; cleaning, packaging and any cleanliness verification are agreed per drawing before quotation.

Which dimensions need individual tolerances?

General tolerances suit the faces that do not mate with anything. Sealing faces, O-ring grooves, locating bores and the interfaces to adjacent modules need individual tolerances, stated with the surface condition they apply to. A general class such as ISO 2768-m, which our network applies as standard, covers the rest.

Coatings move dimensions. The Aluminum Anodizers Council gives 50 % penetration and 50 % buildup per surface as the generally accepted split for hard (type III) coatings. ISO 10074:2021 is the standard for hard anodic oxidation coatings. A worked example: a 50 µm hard coat adds about 25 µm to every surface, so a bore loses about 50 µm in diameter. An H7 tolerance on a 25 mm bore has a band of 21 µm (ISO 286, IT7 for 18 to 30 mm), so the coating alone exceeds the band by more than a factor of two. The drawing must therefore say whether a dimension applies before or after coating. Standards and chromium rules for other treatments are in surface treatments for machined parts.

Which documents belong to each delivery?

An order that says "with documents" does not say which. Table 2 lists what a buyer in this field typically asks for and what each document proves.

Table 2. Documents for machined semiconductor equipment parts

Source: EN 10204:2004 (DIN EN 10204:2005-01 is current); SAE AS9102C:2023 (issued 2023-06-28, current); SEMI F20-0923; ISO 14644-9:2022.

A 3.1 certificate documents the material, not the finished dimensions. The difference between the document types is explained in quality documents for machined parts. AS9102 is an aerospace standard; outside aerospace it applies when the purchase order names it.

Does export control apply to machined parts for chip equipment?

It can. On 8 September 2025 the European Commission adopted a Delegated Regulation that updates Annex I of Regulation (EU) 2021/821, the EU list of dual-use items. The Commission lists semiconductor manufacturing and testing equipment and materials among the items added. Regulation (EU) 2021/821 provides for export authorisations, among them EU general export authorisations and individual licences.

Frequently asked questions

What does SEMI F19 regulate?

SEMI F19 gives quality requirements for the wetted surfaces of stainless steel components in semiconductor gas and liquid distribution systems. It defines surface characterization and finish acceptance criteria for tubing and components made to SEMI F20, and refers to SEMI F37 for the roughness parameters. The current edition is SEMI F19-0815.

Is a cleanroom class a cleanliness requirement for a machined part?

No. ISO 14644-1:2015 classifies the air in a cleanroom by particle concentration. The surface of a part is assessed under ISO 14644-9:2022, which covers particles from 0.05 µm to 500 µm and leaves the cleaning procedure and the process-specific limit to the user.

Is 1.4404 the same as 316L to SEMI F20?

No. 1.4404 is the usual EN 10088 counterpart of 316L, but SEMI F20 adds metallurgical cleanliness requirements to the composition. A drawing that needs SEMI F20 material has to name SEMI F20, and the material certificate has to refer to it.

Does hard anodizing change the dimensions of a part?

Yes. The Aluminum Anodizers Council gives 50 % penetration and 50 % buildup per surface as the generally accepted split of the coating thickness. A 50 µm hard coat therefore adds about 25 µm to each surface and takes about 50 µm off a bore diameter.

Is ISO 14644-13 new?

The 2026 edition is. EN ISO 14644-13:2026, guidance on cleaning surfaces to a defined level of particle and chemical cleanliness, was published in May 2026 and is listed as the successor of the 2017 edition.

Sources

1. SEMI F19-0815, Surface condition of the wetted surfaces of stainless steel components, current edition (SEMI store)
2. SEMI F20-0923, 316L stainless steel for general purpose, high purity and ultra-high purity applications, current edition (SEMI store)
3. EVS-EN ISO 14644-1:2015, Classification of air cleanliness by particle concentration (EVS)
4. EVS-EN ISO 14644-9:2022, Assessment of surface cleanliness for particle concentration (EVS)
5. EN ISO 14644-13:2026, Cleaning of surfaces to achieve defined levels of cleanliness, published 2026-05-18 (Genorma)
6. ISO 10074:2021, Hard anodic oxidation coatings on aluminium and its alloys, edition 4 (ISO catalogue)
7. Anodizing Reference Guide, Aluminum Anodizers Council (50 % penetration, 50 % buildup per surface)
8. ISO 286-1 standard tolerance grades, IT7 for 18–30 mm (table reproduced on Wikipedia)
9. DIN EN 10204:2005-01, German version of EN 10204:2004, current (DIN Media)
10. Types 3.1 and 3.2 as worded in EN 10204:2004 (Van Leeuwen, steel tube stockist)
11. SAE AS9102C:2023, First Article Inspection Requirements, issued 2023-06-28, current (DIN Media)
12. 2025 update of the EU control list of dual-use items, adopted 2025-09-08 (European Commission, DG Trade)
13. Exporting dual-use items, authorisations under Regulation (EU) 2021/821 (European Commission, DG Trade)

Questions on a drawing? sales@ertas.engineering

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