| CPC H01L 21/76873 (2013.01) [C25D 3/38 (2013.01); C25D 5/02 (2013.01)] | 19 Claims |
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1. A method, comprising:
placing a substrate in a cup of a substrate holder;
positioning a cone over the substrate, the cone including at least three distance measuring devices arranged on a lower surface thereof and facing the substrate;
moving the cone toward the cup to engage the cup and thereby form a fluid tight seal between the cone and the cup;
transmitting laser pulses using each of the at least three distance measuring devices towards the substrate, wherein the laser pulses impinge on a surface of the substrate and within a circumferential edge of the substrate, and each of the at least three distance measuring devices impinges the laser pulses on the surface of the substrate;
waiting for an amount of time to receive reflected laser pulses from the substrate at each of the at least three distance measuring devices;
upon receipt of the reflected laser pulses within the amount of time, determining an inclination of the substrate by,
calculating turnaround times for the laser pulses using corresponding distance measuring devices;
calculating, using the corresponding distance measuring devices, distances between each of the distance measuring devices and the substrate, the distances being calculated using the turnaround times; and
determining whether differences between the distances calculated by the distance measuring devices are within a desired threshold value;
upon absence of receipt of the reflected laser pulses within the amount of time, generating a notification indicating absence of reflected laser pulses at one or more of the at least three distance measuring devices; and
performing a plating operation on the substrate after determining the inclination of the substrate.
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