Ablation Of Film Stacks In Solar Cell Fabrication Processes
AssigneeSunPower Corporation
InventorsGabriel HARLEY, Taeseok KIM, Peter John COUSINS
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Abstract
A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.
Claims21
A method of fabricating a solar cell, the method comprising:
- providing a film stack comprising a first film and a second film, the first film being formed over the second film, the first film comprising a material that is absorptive in a wavelength of operation of a laser source;
- in a single pulse repetition of the laser source firing at a pulse repetition rate, forming a hole through the first film and the second film to expose another layer of material under the second film.
A method of fabricating a solar cell, the method comprising:
- firing one laser pulse within a single repetition of a laser source that is firing laser pulses at a repetition rate, the one laser pulse being temporally asymmetric and having a first peak and a second peak, the first peak occurring first in time relative to the second peak in the single repetition, the first peak having an energy higher than that of the second peak;
- ablating a first film and a second film of a film stack with the first peak of the one laser pulse to form a hole through the first film and the second film, the second film being electrically conductive;
- and
- ablating a third film of the film stack with the second peak of the one laser pulse to form the hole through the first film, the second film, and the third film of the film stack to expose a diffusion region of the solar cell through the hole.
A method of fabricating a solar cell, the method comprising:
- firing a first laser pulse and a second laser pulse within a single repetition of a laser source that is firing laser pulses at a repetition rate;
- ablating a first film and a second film of a film stack with the first laser pulse to form a hole through the first film and the second film, the second film being electrically conductive;
- and
- ablating a third film of the film stack with the second laser pulse to form the hole through the first film, the second film, and the third film of the film stack to expose a diffusion region of the solar cell through the hole.
Dependencies are inferred from the claim text.