Patent ID: 8298370

Claim:
An apparatus for chemical vapor deposition (CVD) with a showerhead through which a source of material gas comprising a reactive gas of at least one kind and a purge gas are injected over a substrate located in a reaction chamber to deposit a film on the substrate, wherein the showerhead includes: a first reactive gas showerhead module having an upper plate and a bottom plate, and defining an enclosed inner space between the upper plate and the bottom plate thereof for receiving a first kind of reactive gas therein, the first reactive gas showerhead module having a plurality of reactive gas flow channels connected thereto and extending toward the substrate for injecting the first reactive gas over the substrate; a second reactive gas showerhead module having an upper plate and a bottom plate, and disposed below the first reactive gas showerhead module, the upper plate of the second reactive gas showerhead module being separable from the bottom plate of the first reactive gas showerhead module, the second reactive gas showerhead module defining an enclosed inner space between the upper plate and the bottom plate thereof for receiving a second kind of reactive gas therein, the second reactive gas showerhead module having a plurality of reactive gas flow channels connected thereto and extending toward the substrate for injecting the second reactive gas over the substrate, the reactive gas flow channels of the second reactive gas showerhead module disposed at locations spaced apart from where the reactive gas flow channels of the first reactive gas showerhead module are located; and a purge gas showerhead module having an upper plate and a bottom plate, and disposed below the second reactive gas showerhead module, the upper plate of the purge gas showerhead module being separable from the bottom plate of the second reactive gas showerhead module, the purge gas showerhead module having a purge gas supply port for supplying a purge gas thereto, an enclosed inner space separated from the inner spaces of the first and second reactive gas showerhead modules for receiving the purge gas therein, a plurality of inlets formed on the upper surface thereof for allowing said reactive gas flow channels to pass thereto with hermetic sealing at joints of said inlets, a plurality of exits for said reactive gas flow channels and a plurality of exits for said purge gas formed on the bottom surface of the purge gas showerhead module to allow the injection of the reactive gases and the purge gas there-through, wherein each reactive gas flow channel of the first reactive gas showerhead module passes through the inner space of the second reactive gas showerhead module and through the inner space of the purge gas showerhead module.