PURPOSE: To improve exhaust efficiency, to reduce deposit and to obtain highly uniform quartz glass by discharging an inert gas through the gas pipe equipped on the inner wall of a furnace.
CONSTITUTION: A burner 2 is laid with its tip set from the top of a furnace 1 toward a target 4. A furnace wall is equipped with an observation window and an exhaust pipe, respectively. At the lower part of the furnace, the target 4 for forming an ingot 3 is installed. SiCl4 and a carrier gas as a raw material gas and an O2 gas and an H2 gas as combustion and reaction gases are sprayed from the tip of the burner 2. SiCl4 is hydrolyzed by the flame by combustion and reaction gases into synthetic quartz and piled on the target to form an ingot. The synthesized face at the top of the ingot is covered with flame by the combustion gas. A gas pipe made of quartz glass is arranged at a part, to which a deposit is liable to attach itself, in the inner wall of the furnace. Since variability of a gas amount becomes a factor of disturbance to damage stability of atmosphere, a flow rate is regulated by a mass flow controller.
TAKANO JUN
KOMINE NORIO
JINBO HIROKI
HIRAIWA HIROYUKI
