Ask Lewis Bass: A Question About SEMI S2/S8 Evaluations

Ask Lewis Bass: A Question About SEMI S2/S8 Evaluations

Welcome to another blog in our ongoing series, Ask Lewis Bass!

This series features actual submitted questions from companies in the industries we provide engineering safety consulting services to.

Topics covered include those associated with our work in 3rd party field labeling, SEMI S2/S8/EMC/F47 testing and design, CE Marking evaluations, and general engineering safety consulting questions.


Hi Lewis Bass, what exactly is needed for a SEMI S2/S8 evaluation? The machine is still in the design stage and I’ve heard that having complete documentation is a must. Is there anything else I should be aware of to have this evaluation proceed without delay when the machine is ready?


Asked by Jasbinder in Fremont, CA


Lewis Bass:

Great question, Jasbinder. Evaluating a machine to SEMI standards is a documentation-heavy process and the final report will rely on much of this supporting material to draw accurate conclusions and recommendations for mitigation (if found not compliant on certain sections).

When preparing for an SEMI S2/S8 assessment, our engineering team would expect to receive the following from your company:

  1. A BOM (Bill of Materials),
  2. An up-to-date operating manual,
  3. A maintenance manual,
  4.  Full machine schematics (block diagram is helpful, but not necessary).

We often see these initial documentation requests as a blocker with companies seeking SEMI certification because the tool is either still in the development stage like your machine is; and no one has taken the time to start writing the manuals, or in some other cases the documentation has been lost along the way due to ownership transfers.

Another common blocker to be aware of is Seismic Protection/Analysis, SEMI is pretty specific on what they want to see here and in some cases, it can be ever more stringent:

The user might require more stringent design criteria than what are given here because of increased site vulnerability (e.g., local soil conditions and building design may produce significantly higher accelerations), alternate installation scenarios, or local regulatory requirements”  – SEMI Document 5556B, Page 16.

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