Patent ID: 8591655

Claim:
A film-forming apparatus comprising: a gas-mixing chamber for admixing a raw gas and a reactive gas; a film-forming chamber connected to the gas-mixing chamber; a gas mixture supply port defining a dimensionally constant clearance between a bottom portion of the gas-mixing chamber and a circular shower head and positioned at a periphery of the bottom portion of the gas-mixing chamber; the circular shower head disposed at a top face of the film-forming chamber and having a plurality of gas-injection holes defined therethrough, each gas-injection hole directly opposing the gas-mixing chamber; a stage for placing thereon a substrate to be processed, the stage being disposed inside the film-forming chamber and moveable in an up and down manner; an exhaust port for discharging an exhaust gas from inside the film-forming chamber to outside of the film-forming chamber, the exhaust port being formed through a wall surface of the film-forming chamber in a position below the stage at a time of film formation, the exhaust gas generated in a space defined by the shower head and an upper face of the stage is discharged out of the exhaust port through a clearance between a side wall of the film-forming chamber and the stage; and a gas mixture initially prepared in the gas-mixing chamber being introduced into the film-forming chamber through the shower head, thereby forming a film on the substrate to be processed, wherein the gas mixture supply port is in fluid communication with the gas-mixing chamber and the shower head and is located on a radially extending line of the shower head, and wherein the gas mixture supply port is so constructed and arranged that the gas mixture to be supplied from the gas-mixing chamber freely flows through the dimensionally constant clearance along an upper surface of the shower head directly from the gas mixture supply port onto the upper surface of the shower head in direct contact with, and only from outside a circumferential outer perimeter of, the upper surface of the shower head and the gas-injection holes toward a central portion along the upper surface of the shower head.