The firing process, also referred to as sintering, is one of the key steps with which the front-metal contact is formed in a silicon solar cell. In this process, the thick film paste is dried at about 150°C to remove much of the solvents. The presence of solvents can cause excessive out gassing which can lead to cracks and voids. The dried substrates are then fired inside a firing furnace. The firing process consists of four primaries. The first step is the initial temperature ramp up where the paste solvents are volatilized. The second step is the burn out. The objective of the burn out phase is to remove all of the organic binder that was used in paste formation. The burn out phase is carried out at 300-400°C. The third step is the sintering, or the firing process, which is done between the ranges of 700-800°C. During this process, the Ag metal forms a bond with the underlying silicon substrate to form metal contact. The final step in the firing process is the wafer cool down phase.