Pattern of apertures in a showerhead for chemical vapor deposition
First Claim
1. A showerhead for distributing process gas to a substrate processing area in a chemical-vapor deposition apparatus, comprising a flat front faceplate having a gas cavity therebehind and having a number of holes therethrough arranged in a generally symmetric pattern about a central axis of said faceplate, said pattern comprising:
- a first plurality of said holes in a first zone occupying a central portion of said faceplate and being arranged with a first density of said holes;
a second plurality of said holes in a second zone of said faceplate surrounding said first zone and being arranged with a second density of said holes greater than said first density; and
a third plurality of said holes in a third zone of said faceplate surrounding said second zone and being arranged with a third density of said holes;
wherein said first, second, and third densities differ by at least 10% among them.
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Accused Products
Abstract
A showerhead used for dispensing gas over a wafer in chemical vapor deposition (CVD), especially for CVD of metals. The patterns of holes is tailored to compensate for thermal and other effects, in particular by increasing the density of holes toward the periphery of the wafer in three or more zones. Such a variable pattern is particularly useful for liquid precursors that are atomized in a carrier gas, in which case a second perforated plate in back of the showerhead face can be eliminated, thereby reducing the flow impedance and the required pressure of the liquid-entrained gas, which tends to deposit out at higher pressures. The reduce flow impedance is particularly useful for CVD of copper.
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Citations
14 Claims
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1. A showerhead for distributing process gas to a substrate processing area in a chemical-vapor deposition apparatus, comprising a flat front faceplate having a gas cavity therebehind and having a number of holes therethrough arranged in a generally symmetric pattern about a central axis of said faceplate, said pattern comprising:
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a first plurality of said holes in a first zone occupying a central portion of said faceplate and being arranged with a first density of said holes; a second plurality of said holes in a second zone of said faceplate surrounding said first zone and being arranged with a second density of said holes greater than said first density; and a third plurality of said holes in a third zone of said faceplate surrounding said second zone and being arranged with a third density of said holes; wherein said first, second, and third densities differ by at least 10% among them. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A showerhead assembly, comprising:
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a port for a source of precursor gas; and a showerhead having a faceplate with a plurality of holes formed therethrough and having a gas cavity formed between said faceplate and said port, no perforated plate being disposed between said faceplate and said port, wherein said plurality of holes are distributed across a radius of said faceplate with a density variation of at least 10% in which said holes have a higher density at an outer portion of said faceplate than in a central portion of said faceplate. - View Dependent Claims (12)
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- 13. A showerhead assembly for distributing a precursor gas for chemical vapor deposition to a substrate being coated in a deposition chamber, comprising a substantially circular faceplate in parallel opposition to said substrate and including a plurality of holes formed therethrough receiving and passing said processing gas from a gas port, wherein a density of said holes varies with a radius from a center of said faceplate to produce a thicker deposition at a peripheral portion of said substrate than at a central portion of said substrate.
Specification