Substrate processing system, load device and method

A load device for a wafer processing system, the load device comprising:

• a first cassette support configured to support thereon a first cassette containing a first lot of wafers;
• at least one first sensor configured to generate a first weight signal corresponding to a first total weight of the first cassette and the first lot of wafers;
• a platform over which the first cassette support is arranged;
• and
• at least one first rod extending downwardly from a bottom of the first cassette support, through the platform, to the at least one first sensor, the at least one first rod configured to transfer a first load corresponding to the first total weight to the at least one first sensor.

A method, comprising:

• obtaining information on a weight difference between a first weight of a first lot of substrates and a second weight of a second lot of substrates;
• and
• based on the information on the weight difference, controlling a processing apparatus to balance a rotation of the first lot of substrates and the second lot of substrates simultaneously,
• wherein an actual weight of a first substrate in the first lot of substrates is different from an actual weight of a second substrate in the second lot of substrates.