Exhaust system with U-shaped pipes

An exhaust system for discharging from semiconductor manufacturing equipment a hazardous gas, comprising:

• a main exhaust pipe positioned above the semiconductor manufacturing equipment and having a top surface on a first side of the main exhaust pipe and a bottom surface on a second side of the main exhaust pipe;
• a first branch pipe connected to a gas mixture containing the hazardous gas on the second side of the main exhaust pipe and connected to the main exhaust pipe through the top surface;
• and
• a second branch pipe connected to a gas box on the second side of the main exhaust pipe and connected to the main exhaust pipe through the top surface,
• wherein the first branch pipe is connected to the main exhaust pipe at a first location, the second branch pipe is connected to the main exhaust pipe at a second location, and
• wherein the first location is more upstream than the second location.

An exhaust system for discharging from semiconductor manufacturing equipment a hazardous gas, comprising:

• a main exhaust pipe positioned below the semiconductor manufacturing equipment and having a top surface on a first side of the main exhaust pipe and a bottom surface on a second side of the main exhaust pipe;
• a first branch pipe connected to a source of a gas mixture containing the hazardous gas on the first side of the main exhaust pipe and connected to the main exhaust pipe through the top surface;
• a second branch pipe connected to a first gas box on the first side of the main exhaust pipe and connected to the main exhaust pipe through the bottom surface;
• and
• a third branch pipe connected to a second gas box on the first side of the main exhaust pipe and connected to the main exhaust pipe through the bottom surface.