The D-SIMCON Photo Optimiser automates the process of adjusting the product/layer dedication in the lithography area of a wafer fab (typically a set of cluster tools comprising coating, exposure and development steps). This is a trade-off between the risk of capacity loss and/or excessive cycle time increase caused by tool downs (in case too few tools are dedicated to a particular product/layer) and the probability of having to carry out additional pilot runs (in case more tools than necessary are dedicated to a particular product/layer).
The D-SIMCON Photo Optimiser takes into account many specific requirements such as
- Number of resists to be installed in each coating tool should be kept low.
- Capacity loss due to cooling time required on certain (typically older) types of lithography tools due to elevated lens temperature from recipes with high intensity and long exposure times should be minimised.
- Reticle movements that might be required in case lithography tools are distributed across several locations in the fab should also be avoided if possible.
The optimisation also considers that
- Once the first critical layer has been allocated, the remaining critical layers need to be allocated to the same tool.
- Preferred usage of “golden tools”.
- Any re-optimised product/layer dedication should be incremental, i.e. the number of dedication changes compared to the previous set of dedications should be kept as low as possible.
The D-SIMCON Photo Optimiser works with conjunction with the D-SIMCON Static Capacity Engine which allocates production volumes to available toolsets with the objective to balance tool utilisation.
Relevant Use Cases: Mid-Term Capacity Management in the Lithography Area