Fab cycle time and capacity planning

I did not discuss the results of the last poll yet. This post will focus on that.

Unfortunately, not a lot of readers did participate. The data is statistically more on the weak side, but I think the outcome is in line with what I was expecting:

It seems that 70% of the voters use a rather simple method to define the maximum allowed tool group utilization. This matches with what I have experienced in a lot of FABs.

Given the massive implications the FAB capacity profile has on the FAB cycle time it is surprising, that in todays heavily data driven world not more advanced methods are used. I wonder what is the reason for that ? Here is some speculation from my end:

  • not enough resources to manage the significant amount of data
  • input data quality for capacity planning is limited due to grouping of products and averaged assumptions
  • real factory performance data is highly dynamic and hard to forecast for the next 2…3 months
  • planning scenarios change so frequently, that a more detailed planning takes more time than the next scenario ask rolls in
  • decision makers are used to simple rules like flat 85% – since they have worked for the last 20 years to some extend and more advanced methods are “black magic” and capital intense decisions will be not based on “black magic”
  • FAB cycle time is more a high level target, the operations/engineering department needs to figure out in the daily business how to get the cycle time down
  • or maybe the FABs which use more advanced methods simply did not vote here

I would love to hear feedback on these topics.

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Over the next weeks my posting activity will slow down a bit due to a lot of travel on my side. One special highlight is coming up with my visit in Dresden, Germany to participate at the

where I will have the honor to give a talk. Check it out here (LINK) and maybe we can meet in Dresden in person . After the event I will post the slides here.

2 thoughts on “Fab cycle time and capacity planning

  1. Would be very interesting to see the link between the traditional methods of capacity determination and the level of fab automation. Today are more the 200 150mm and 200mm fabs in operation. I guess with a lower level of automation and use of data.

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    1. Alexander,
      thank you for your comment. It is indeed an interesting topic. So far I did only see in one FABs capacity model an efficiency loss modeled due to the fact the FAB was run manually. Most other FAB models I have seen do not model Operator availability, which means the assumptions is 100% …
      Curious if someone in the community has experience with that ?
      Thomas

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