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Applying a Sampling Pattern in a Step#

Scenario#

In a semiconductor fab, a Sampling Pattern is used during a Metrology step to check for overlay accuracy. When a lot of 10 Wafers enters the step, Critical Manufacturing MES automatically selects wafers in positions 2, 6, and 10 for In-Step Sampling before the lot continues. This targeted pattern ensures representative wafers across the lot are measured without inspecting all wafers, helping detect process drift early while maintaining high throughput.

Configuration#

  • Create the necessary Critical Manufacturing MES entities to support the scenario, such as Steps, Flows, Resources, and Services.
  • Create the Sampling Pattern to select positions 2, 6, and 10 of the associated Container (SP_OverlayAccuracy).

Screenshot showing a Sampling Pattern configured for positions 2, 6, and 10.

Screenshot showing the StepSamplingPatternContext association for the step.

Execution#

When a Sampling Pattern is used in isolation, the system processes all Material lots in the defined Sampling Step, but it processes only the Sub-Materials in the nominated positions. In this case, 2, 6, and 10 are processed and all others are skipped.

At the In-Step Overlay & Focus Metrology step, perform Dispatch & Track-In on a Material lot with a Container containing the identified positions for its Sub-Materials. For details on the transaction itself, see Track-In Material.

Screenshot showing the lot before track-in at the sampling step.

A second wizard step named Sampling appears, showing the selected container positions to be processed. After the Track-In transaction is complete, the Material lot state changes to In Process, but only the three Sub-Materials in container positions 2, 6, and 10 are In Process. All other Sub-Materials skip processing.

Screenshot showing the Sampling wizard step with the selected positions.

Screenshot showing the resulting in-process sub-materials after sampling track-in.

Note

If at least one of the Sub-Materials in positions 2, 6, or 10 is empty, Critical Manufacturing MES throws an error. Use Evaluation Type System or Rule for these more complex scenarios.

Combine Sampling Plan and Sampling Pattern to guarantee that only Material lots selected by the Sampling Plan will arrive at the step where the Sampling Pattern is configured.

You can see a demonstration of this tutorial in the following video: