An apparatus for bonding a substrate is provided to prevent a part coupled to a lower chamber from being damaged by forming a part of coupling units separately when the lower chamber to support the alignment stage is coupled to a plurality of lift modules through a plurality of coupling units. An upper chamber(200) supports an upper substrate. A lower chamber(300) supports a lower substrate coupled to the upper substrate. An alignment stage is arranged in the lower part of the lower chamber. A plurality of lift modules(910) are connected to the alignment stage(320) through a plurality of coupling units(800,810). The alignment stage is move by coupling a part of the coupling units of the lift module separately. The lift module lifts the alignment stage to lift the lower chamber.
