Laser patterning process for back contact through-holes formation process for solar cell fabrication

A method of forming an opening in a passivation layer on a back surface of a solar cell substrate, comprising:

• transferring a substrate having a passivation layer formed on a back surface of a substrate into a laser patterning apparatus, the substrate fabricated from a crystalline silicon material having a first type of doping atom on the back surface of the substrate and a second type of doping atom formed in a predetermined location on a front surface of the substrate;
• providing laser radiation from the laser patterning apparatus to the passivation layer disposed on the back surface of the substrate, wherein the laser radiation is selected at a wavelength that has minimum absorption to the crystalline silicon material formed in the substrate;
• and
• forming openings in the passivation layer while activating the second type of the doping atoms located in the predetermined location of the front surface.

A method of forming an opening in a passivation layer on a back surface of a solar cell substrate, comprising:

• transferring a substrate having a passivation layer formed on a back surface of a substrate into a laser patterning apparatus, the substrate fabricating from a crystalline silicon material having a first type of doping atom on the back surface of the substrate and a second type of doping atom on a front surface of the substrate;
• providing laser radiation to the passivation layer disposed on the back surface of the substrate from the front surface of the substrate;
• and
• simultaneously forming openings in the passivation layer while thermal annealing a region of the front surface of the substrate to activate the second type of doping atom where the laser radiation is passing therethrough.