Methods and apparatus for patterning photovoltaic devices and materials for use with such devices

A method of shaping a picosecond laser beam for use in patterning photovoltaic devices, the method comprising:

• passing picosecond laser pulses generated from a pulsed fibre laser source at a first laser wavelength and comprising a first spectral bandwidth to a harmonic conversion element to convert the laser pulses at the first laser wavelength to laser pulses at a second laser wavelength comprising a second spectral bandwidth;
• and, passing the laser pulses at the second laser wavelength to a beam shaping apparatus having a beam shaping element having a further spectral bandwidth that substantially corresponds to the second spectral bandwidth so as to produce a laser beam having a substantially rectangular cross-sectional intensity profile;
• and patterning a photovoltaic device with the laser beam having the substantially rectangular cross section intensity profile.

A semiconductor scribing process, comprising:

• passing picosecond laser pulses generated from a pulsed fibre laser source at a first laser wavelength comprising a first spectral bandwidth to a harmonic conversion element to convert the laser pulses at the first laser wavelength to laser pulses at a second laser wavelength comprising a second spectral bandwidth;
• passing the laser pulses at the second laser wavelength to a beam shaping apparatus having a beam shaping element having a further spectral bandwidth that substantially corresponds to a the second spectral bandwidth so as to produce a laser beam having a substantially rectangular cross-sectional intensity profile;
• and, imaging the shaped laser beam comprising the laser pulses at the second laser wavelength using an imaging element onto the semiconductor, to pattern the semiconductor.

A method of shaping a picosecond laser beam for use in scribing photovoltaic devices;

• the method comprising:
• passing picosecond laser pulses generated from a pulsed fibre laser source in a wavelength range 500-550nm to a shaping element for providing a shaped picosecond pulsed laser beam;
• and scribing a photovoltaic device with the shaped laser beam.