Abstract: A method of processing a substrate includes: locating the substrate and a first connector between a bonding head and an optical radiation detector, the substrate having an optical radiation conductive zone and a second connector that is at least partially coincident with the optical radiation conductive zone; and bonding the first connector to the second connector so as to form an electronic connection between the first connector and the second connector, wherein bonding includes moving the bonding head away from both the first connector and the second connector after a time period that is at least in part a function of a temperature that is measured by the optical radiation detector.