Method to enhance the adhesion of silicon nitride to low-k fluorinated amorphous carbon using a silicon carbide adhesion promoter layer
First Claim
1. A method of fabricating an integrated circuit, comprising the steps of:
- providing a substrate;
depositing a fluorinated amorphous carbon layer on the substrate;
depositing a silicon carbide layer on the fluorinated amorphous carbon layer; and
depositing a silicon nitride layer on the silicon carbide layer.
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Accused Products
Abstract
A plasma enhanced chemical vapor deposition (PECVD) process is provided for depositing one or more dielectric material layers on a substrate for use in interconnect structures of integrated circuits. The method comprises the steps of depositing a fluorinated amorphous carbon (a-F:C) layer on a substrate by providing a fluorine containing gas, preferably octafluorocyclobutane, and a carbon containing gas, preferably methane, in ratio of approximately 5.6, so as to deposit a a-F:C layer having an internal compressive stress of approximately 28 MPa After deposition the film is annealed at approximately 400° C. for approximately two hours. An adhesion promoter layer of relatively hydrogen-free hydrogeneated silicon carbide is then deposited on the a-F:C layer using silane (SiH4) and methane (CH4) as the deposition gases. The silicon carbide layer may be deposited at a rate of approximately 180 Å per minute and typically results in deposition of a silicon carbide layer having an internal compressive stress of approximately 400 MPa. The deposited silicon carbide layer has relatively few hydrogen bonds thereby yielding a compact structure which promotes adhesion of the a-F:C layer to a silicon nitride layer and to the a-F:C layer, and which reduces diffusion of fluorine through the silicon carbide layer. A silicon nitride layer is then deposited on the adhesion promoter layer, the deposition materials preferably comprising silane (SiH4) and nitrogen (N2) in a ratio of 30:100 at 400° C. The silicon nitride layer formed has relatively few hydrogen bonds thereby resulting in a layer having an internal compressive stress of approximately 240 MPa This stacked layer structure has thermal stability and resists peeling and cracking up to 450° C., and the a-F:C dielectric layer has a dielectric constant (k) as low, or lower, than 2.5.
41 Citations
11 Claims
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1. A method of fabricating an integrated circuit, comprising the steps of:
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providing a substrate;
depositing a fluorinated amorphous carbon layer on the substrate;
depositing a silicon carbide layer on the fluorinated amorphous carbon layer; and
depositing a silicon nitride layer on the silicon carbide layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of fabricating an integrated circuit, comprising the steps of:
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providing a substrate;
depositing a single fluorinated amorphous carbon layer on the substrate;
depositing a silicon carbide layer directly on the single fluorinated amorphous carbon layer; and
depositing a silicon nitride layer on the silicon carbide layer.
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Specification