| 摘要 |
In a gas supply device called a gas shower head or the like, the occurrence of dense areas of particles such as cross-like particles is suppressed and the degree of freedom of process conditions is increased by making more uniform the flow velocity distribution of gas flows from the center to the outer peripheral parts of a board along the circumferential direction than before. The arrangement pattern of gas supply holes formed in the shower plate of the gas supply device is so set that these holes are arranged on a large number of concentric circles and that a gas supply hole on a concentric circle and gas supply holes nearest that gas supply hole and on concentric circles respectively inwardly and outwardly adjacent to that concentric circle are not arranged in the radial direction of the concentric circles.
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