An apparatus for manufacturing a semiconductor device includes a chamber including a lower housing and an upper housing, heater chucks in the lower housing, shower heads on the heater chucks, the shower heads being between the lower housing and the upper housing, power supplies connected to the shower heads to provide radio-frequency powers to the shower heads, power straps in the upper housing to connect the shower heads to the power supplies, and shielding members in the upper housing, the shielding members enclosing the power straps and the shower heads, respectively, the shielding members to prevent electromagnetic interference of the radio-frequency powers between the power straps and between the shower heads.