A method for large scale manufacture of photovoltaic devices includes loading a substrate into a load lock station and transferring the substrate in a controlled ambient to a first process station. The method includes formation of a first conductor layer overlying the surface region of the substrate. The method includes transferring the substrate to a second process station, and forming a second layer overlying the surface region of the substrate. The method further includes repeating the transferring and processing until all thin film materials of the photovoltaic devices are formed. In an embodiment, the invention also provides a method for large scale manufacture of photovoltaic devices including feed forward control. That is, the method includes in-situ monitoring of the physical, electrical, and optical properties of the thin films. These properties are used to determine and adjust process conditions for subsequent processes.