Methods & apparatus for controlling an industrial process

A control apparatus for an industrial process performed on a series of product units, the control apparatus comprising:

• a selection arrangement configured to select one or more of the product units as one or more sample product units for metrology;
• and
• a correction arrangement configured to use metrology results of the selected one or more sample product units to define corrections for use in controlling processing of the plurality of product units and/or of similar product units,
• wherein the selection arrangement is configured to receive object data representing one or more parameters measured in relation to the plurality of product units and configured to select the one or more sample product units based at least partly on statistical analysis of the object data.

A non-transitory computer program product comprising machine readable instructions therein, the instructions, when executed by a data processing system, configured to cause the data processing system apparatus to at least:

• receive object data representing one or more parameters measured in relation to a plurality of product units;
• select one or more of the product units as one or more sample product units, the selection of the one or more sample product units based at least partly on statistical analysis of the object data;
• obtain metrology results from the performance of one or more metrology steps only on the selected one or more sample product units out of the plurality of product units;
• and
• based at least partly on the metrology results of the selected one or more sample product units, define corrections for use in controlling an industrial process performed on the plurality of product units and/or similar product units.