Detection of contact formation between a substrate and contact pins in an electroplating system

A method, comprising:

• loading a substrate on a substrate holder, wherein loading the substrate comprises:
• pressing a cone on a back surface of a substrate;
• and
• bringing a front surface of the substrate into contact with first and second contact pins on the substrate holder;
• measuring a first resistance of a first contact between the first contact pin and the substrate;
• measuring a second resistance of a second contact between the second contact pin and the substrate;
• comparing a predetermined range with a difference between the first and second resistances to generate a comparison result;
• generating, based on the comparison result, a signal to indicate a status of the first and second contacts;
• and
• unloading, in response to the difference between the first and second resistances being outside the predetermined range, the substrate from the substrate holder.

A method, comprising:

• forming a first contact between a front surface of a substrate and a first contact pin;
• forming a second contact between the front surface of the substrate and a second contact pin;
• bringing a back surface of the substrate into contact with first and second sensors opposite to the first and second contacts, respectively;
• measuring, by the first and second sensors, first and second resistances of the first and second contacts, respectively;
• determining a contact status of the first contact and the second contact based on the first and second resistances;
• and
• in response to a difference between the first and second resistances being within a predetermined range, performing an electroplating operation on the front surface of the substrate.