In one embodiment, a semiconductor manufacturing apparatus includes a support module configured to support a wafer having first and second faces. The apparatus further includes a chamber configured to contain the support module. The apparatus further includes a microwave generator configured to generate a microwave. The apparatus further includes a waveguide configured to emit the microwave into the chamber to irradiate the first or second face of the wafer with the microwave, the waveguide being provided to the chamber such that an incidence direction of the microwave emitted from the waveguide onto the first or second face is non-vertical to the first or second face.