Meeting fab cycle time commitment during production ramp

Balancing cycle time and capacity during production ramp is always a challenge. One method that can be used to achieve balance between these two is to maximize throughput on certain tools and emphasize compliance on cycle time, CT, for the balance of the other tools. Litho equipments being the most expensive equipment in a fab is used to maximize throughput. Once lots are out of Litho, the other area tools is to follow strictly on the CT compliance rules. Cycle time compliance rules requires the most delayed lots on a particular equipment type is to be executed first. Rate of execution on Litho equipment and rate of compliance on other tools is measured on daily basis. Our experiment indicates if the rate of execution in the Litho is at 85% and above while the compliance of rules on other tools is above 80%, we can achieve cycle time commits and meet the fab capacity requirement at the same time