Imprint Lithography Cable Strain Sensing for Force Accuracy

The patent implements a feedback mechanism by measuring the actual position of the imprint head using sensors (such as linear variable differential transformers or laser interferometers) and using this measured position to correct the estimated force. The correction formula F_corrected = F_estimated + k*(z_measured - z_estimated) applies feedback from position measurement to compensate for the viscoelastic effects in cable assemblies, thereby resolving the contradiction between maintaining easy signal supply through cables and achieving accurate force estimation.

The patent applies preliminary action by measuring the position of the imprint head at multiple points along the trajectory before the final imprint force is applied. These preliminary position measurements are used to calculate correction factors that compensate for cable strain effects. By performing these measurements and calculations in advance, the system establishes a corrected force profile that accounts for the specific trajectory and cable deformation, thereby improving repeatability while maintaining alignment precision.

The patent replaces the mechanical force measurement approach with a sensor-based position measurement system. Instead of relying on mechanical force sensors that would be affected by cable viscoelasticity, the system uses non-contact or minimal-contact sensors (such as laser interferometers or capacitive sensors) to measure the actual position of the imprint head. This substitution of the measurement mechanism eliminates the direct coupling between cable mechanical behavior and force measurement, thereby maintaining full imprint head functionality while improving force accuracy.