Alignment mark recovery method and lithographic apparatus

A lithographic apparatus comprising:

• a support constructed to support a patterning device, the patterning device being capable of imparting a radiation beam with a pattern in its cross-section to form a patterned radiation beam;
• a substrate table constructed to hold a substrate;
• and
• a projection system configured to project the patterned radiation beam onto a target portion of the substrate;
• and
• a control system to control operation of the lithographic apparatus, wherein the control system is configured to cause the lithographic apparatus to at least:
• form one or more alignment marks in a mark layer of the substrate, wherein an alignment mark of the one or more alignment marks is formed by exposing a resist covering the mark layer to the patterned radiation beam thereby forming an alignment pattern in a first mark area of the resist corresponding to the alignment mark;
• and
• form one or more recovery marks in the mark layer, wherein a recovery mark of the one or more recovery marks is formed by:
• exposing the resist to at least a portion of the patterned radiation beam thereby forming an alignment pattern in a second mark area of the resist, and
• subsequently exposing the second mark area of the resist, each time with a shifted patterned radiation beam until a substantial part of the second mark area has been exposed.

A computer-readable medium comprising computer readable code therein, the computer readable code, when executed by a computer system, configured to cause the computer system to at least cause:

• formation of one or more alignment marks in a mark layer of a substrate, wherein an alignment mark of the one or more alignment marks is formed by exposure of a resist covering the mark layer to a patterned radiation beam thereby forming an alignment pattern in a first mark area of the resist corresponding to the alignment mark;
• and
• formation of one or more recovery marks in the mark layer, wherein a recovery mark of the one or more recovery marks is formed by:
• exposure of the resist to at least a portion of the patterned radiation beam thereby forming an alignment pattern in a second mark area of the resist, and
• one or more subsequent exposures of the second mark area of the resist, each time with a shifted patterned radiation beam until a substantial part of the second mark area has been exposed.