Abstract: An exhaust system for a semiconductor etcher that utilizes corrosive gas. Specifically, the present invention exhausts residual corrosive gas from the exit load lock compartment of a semiconductor etcher. For instance, at the completion of the etching process of semiconductor wafers, the exit load lock compartment of an etcher contains the etched wafers along with residual corrosive gas. When the exit load lock compartment pressure returns to about 1 atmosphere, the residual corrosive gas begins to escape. Within an embodiment of the present invention, an exhaust box is adjacently located to the exit load lock compartment to exhaust the residual corrosive gas from it. The exhaust box is a specifically shaped hollow box that has an intake slot and an exhaust aperture. Two edges that partly form the intake slot are parallel to the outer side edge of the exit load lock compartment when its door is open. The intake slot length matches the outer side edge length of the exit load lock compartment.