Detecting and repairing defects of photovoltaic devices

An apparatus for both detecting and repairing a shunt defect in a solar cell substrate, the apparatus comprising:

• a chuck for holding the substrate and providing electrical connection to a back side of the substrate,
• a shunt detection module for detecting the shunt defect in the substrate, the shunt detection module including,
• a lock-in thermography station having,
• a light emitting diode illumination source for providing illumination to the substrate, thereby inducing current in the solar cell, and
• an infrared camera for detecting the shunt defect,
• a process diagnostic module for determining whether the substrate should be one of passed without further processing by the apparatus, rejected without further processing by the apparatus, and repaired by the apparatus, based at least in part on results of the lock-in thermography, and
• a shunt repair module for locating and electrically isolating the shunt defect in the substrate, the shunt repair module having,
• a first laser set at a first relatively lower energy for inducing current in the substrate,
• an imaging means for determining a location of the shunt defect in the substrate during the inducing of the current, and
• a second laser set at a second relatively higher energy for forming an electrically nonconducting area around the shunt defect by at least one of melting a portion of the substrate around the shunt defect and ablating a portion of the substrate around the shunt defect.