Method and system for laser separation for exclusion region of multi-junction photovoltaic materials

A method for processing a thin film device by laser separation, the method comprising:

• providing an optically transparent substrate having a thickness, a back surface region, a front surface region, and an edge region;
• forming a thin film device on the optically transparent substrate, the thin film device including a conductive layer overlying the front surface region and an edge portion overlying the edge region;
• covering the back surface region except an exposed area along the edge region;
• aligning a laser beam from the back surface region through the thickness of the optically transparent substrate to irradiate a first spot within the edge region;
• energy from the laser beam thereby selectively removing part of the edge portion to form a remaining side wall portion to expose at least the conductive layer, a P-type semiconductor layer overlying the conductive layer, a N-type semiconductor layer overlying the P-type semiconductor layer, and an electrode layer overlying the N-type semiconductor layer, exposed edges of the plurality of layers being substantially free from residue particles;
• and
• scanning the laser beam along the exposed area.