Patent ID: 8444800

Claim:
A manufacturing method of silicon seed rod joining two silicon seed rods into one long silicon seed rod by welding, comprising the steps of: disposing an upper silicon seed rod and a lower silicon seed rod vertically in a chamber so as to face a lower end of the upper silicon seed rod and an upper end of the lower silicon seed rod each other; arranging an induction-heating coil around the lower end of the upper silicon seed rod; heating the upper end of the lower silicon seed rod to glow by a preheating ring which is disposed below the induction-heating coil and is induction-heated; elevating the lower silicon seed rod so as to transfer heat from the glowing lower silicon seed rod to the lower end of the upper silicon seed rod so that the lower end of the upper silicon seed rod and the upper end of the lower silicon seed rod glow; melting the glowing lower end of the upper silicon seed rod and the glowing upper end of the lower silicon seed rod by induction-heat of the induction-heating coil in a state in which a gap is made between the lower end of the upper silicon seed rod and the upper end of the lower silicon seed rod; bringing the lower end of the upper silicon seed rod and the upper end of the lower silicon seed rod into contact with each other in molten state; and cooling the upper silicon seed rod and the lower silicon seed rod so that the upper silicon seed rod and the lower silicon seed rod are welded together.