Substrate warpage determination system

A substrate warpage determination system, comprising:

• at least three first supporting devices forming a first substrate support area configured to carry a substrate;
• at least three second supporting devices forming a second substrate support area configured to carry the substrate;
• an actuator configured to move the at least three second supporting devices in a vertical direction;
• and
• a controller configured to drive the actuator, wherein the controller is configured to:
• determine a force exerted by the actuator;
• determine a position in the vertical direction of the second substrate support area relative to the first substrate support area;
• and
• drive the actuator to move the at least three second supporting devices from one of:
• a lower position, wherein the second substrate support area is below the first substrate support area, as seen in a vertical direction, in order to carry the substrate by the first substrate support area, and
• an upper position wherein the second substrate support area is above the first substrate support area, as seen in the vertical direction, in order to carry the substrate by the second substrate support area, to the other one of the lower position and the upper position, and
• determine the force exerted by the actuator at the position in the vertical direction of the second substrate support area relative to the first substrate support area, as the at least three second supporting devices move from the one of the lower position and the upper position to the other one of the lower position and the upper position;
• compare the determined force exerted by the actuator at the position in the vertical direction of the second substrate support area relative to the first substrate support area to a predetermined force at a predetermined position in the vertical direction of the second substrate support area relative to the first substrate support area, and
• determine a warpage of the substrate from the comparison.