TECHNOLOGY FOCUS - INDUSTRIAL STANDARDS - Preferred Method: In producing back contacts on silicon solar cells, separating the silicon material layer (108) comprises opening the area (C) to such an extent that the exposed silicon surface in the area (C) is removed, where separating the silicon material layer (108) is performed by depositing a patterned reflective material (116) on the area (C). Also, step (b) and (c) can be done simultaneously. On the other hand, step (a) is performed after step (b). Step (c) and (d) is performed simultaneously, and step (e) is performed before step (c). The passivating layer (113) is an amorphous silicon layer (106) and an amorphous silicon nitride layer (107) deposited onto the amorphous silicon layer (106), where step (e) is performed by removing at least the silicon nitride layer (107). The deposition of the metal layer (109) in step (f) is performed by electroless plating, electroplating, evaporation through a mask or sputtering though a mask. Depositing the metal (110) in step (h) is performed by electro plating of copper. Alternatively, producing back contacts on silicon solar cells (100) and the interconnection between silicon solar cells (100) where the front surface has been fully treated and the back surface has been processed to the point where the solar cells (100) can be contacted on the back surface comprises: (a) attaching the solar cells (100) onto the transparent superstrate (104), thus forming the structure (120); (b) depositing the passivating layer (113) onto the back surface of the structure (120); (c) depositing the silicon material layer (108) onto the back surface of the structure (120); (d) separating the silicon material layer (108) by first areas (C); (e) providing contact sites in areas (B); (f) depositing the metal layer (109) onto the back surface of the structure (120); (g) heating the structure (120) to form suicide (110); (h) opening the metal layer (109) in areas (C); and (i) depositing metal (112) onto the suicide (110). Separating the silicon material layer (108) comprises opening the area (C) to such an extent that no silicon material resides in the area (C); and depositing a patterned reflective material (116) on the area (C). Moreover, step (b) and (c) can be done in the same step, where step (a) is performed after step (b). Step (c) and (d) is performed simultaneously, and where step (e) is performed before step (c). The passivating layer (113) comprises an amorphous silicon layer (106) and an amorphous silicon nitride layer (107) deposited onto the amorphous silicon layer (106). Step (e) comprises removing at least the silicon nitride layer (107). Opening the metal layer (109) in step (h) is performed by laser ablation of the metal layer 109 in areas (C). The metal layer (109) in step (h) is performed by exposing the structure (120) to a selective etch. Depositing the metal (110) in step (i) is performed by electro plating of copper.