CAST-10-06-09.Test Cell and Yield management WG

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Summary from Test Cell Communication/Yield Enhancement WG

October 6, 2009 CAST Meeting


  • The backend segment is behind in adopting SECS/GEM while Front end is 100% adopted
  • If SECS/GEM is std. then they would require it.
  • Need for real time monitoring of yield, OEE binning, test time
  • Wish to control test hardware (dib, tester, handler) versions
  • Desires a standard (one standard) wafer map format


  • High speed data acquisition - 100's times/sec for non test events
    -Temperature changes
  • TSEM E116, HSEM required
    Did not roll back std. into existing equipment (probers) only new equipment benefits
  • Tester/handler do not talk directly but via cell controller
  • Use Ethernet for tester/handler
    - claims a study was done to prove this was correct solution and was not slow


  • Use STIL and STDF
  • Capacity a big issue while driving factory. Ramping is key today
  • Load boards may go to a daughter card design due to multisite matching problems
  • Perhaps use loopback to reduce tester complexity for multi gigabit serial testing protocol aware testing is key to faster introductions


  • Time to market is king
  • Test cost reduction also important
  • Standardization make this easier
  • Any standards are good as they reduce uncertainty
  • Adaptive test needs standards

Test cell communication & Yield Enhancement Workgroups decided to join into one breakout session as "Yield management"/ "adaptive test" were not well defined.

Meeting group comments

  • SECS/GEM not common on backend test floors
  • Don't jump to SECS without some thought
  • Should the tester talk to the handler?
    - Would be preferable if it did not but what about test time?
  • What about the operator interface? Should it be web browser based?
  • How far should the discussion on interfaces go
    - Just the tester.
    - The Cell ( tester, handler, controller)
    - The floor
  • And how much interaction with the front end and even with EDA

Results from meeting:

At the end of the day, the group decided to focus on these 6 topics (with this priority)

1. High Speed link for Data within the cell and the floor
2. Test Plan model and API to allow interaction with the model by the site controller
3. SECS as the control interface. GEM as the basis for the models
4. Floor Events. Standardization of non test events
5. Test Plan control by adaptive yield processes
6. Device Tracking to allow part tracking from front end to back end to customer.