Method of aligning a first article relative to a second article

A method of aligning a first article relative to a second article, the method comprising steps of:

• providing said second article with at least one flexible structure fixed relative to said second article at at least one point, said flexible structure having a sensing tip and a thermal actuator permitting deflection of the flexible structure between at least a first advanced position and a second retracted position, the thermal actuator operates via differential thermal expansion;
• providing said first article having at least one surface relief marking on said first article, the surface relief marking having a topology,
• providing a memory containing reference information which is pre-stored in said memory prior to initiation of aligning said first article relative to said second article, said reference information relating to the topology of said surface relief marking and during and after aligning said first article relative to said second article,
• deflecting said flexible structure to move the sensing tip to at least said first advanced position in which the sensing tip is disposed in front of a front face of said second article,
• providing a piezoresistive detector for measuring an interaction of the flexible structure with the surface relief marking and generating detector signals relating to said interaction, wherein the piezoresistive detector comprises four piezoresistors associated with the flexible structure;
• identifying with the help of the detector signals, a relative position of the flexible structure and thus of the second article with respect to the surface relief marking by comparison of said detector signals relating to said interaction with the reference information pre-stored in said memory relating to the topology of said surface relief marking to generate position control signals relating to a desired alignment,
• generating relative movement between the first and second articles to achieve the desired alignment between the first and second articles defined by the surface relief marking,
• moving said sensing tip to said second retracted position, and
• generating relative contacting movement between said first and second articles in a position of the desired alignment with said sensor tip in said second retracted position.