Sharp Laboratories of America, Inc

Other

Sharp Kabushiki Kaisha Corporation

Sharp Microelectronics Technology, Inc.

Hongning Yang

Tue H Nguyen

Sheng Teng Hsu

David R Evans

Yanjun Ma

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&deg; 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 (SiH ) and methane (CH ) as the deposition gases. The silicon carbide layer may be deposited at a rate of approximately 180 &angst; 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 (SiH ) and nitrogen (N ) in a ratio of 30:100 at 400&deg; C. The silicon nitride layer 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&deg; C., and the a-F:C dielectric layer has a dielectric constant (k) as low, or lower, than 2.5.

Use of a silicon carbide adhesion promoter layer to enhance the adhesion of silicon nitride to low-k fluorinated amorphous carbon

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&deg; 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 (SiH ) and methane (CH ) as the deposition gases. The silicon carbide layer may be deposited at a rate of approximately 180 &angst; 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 (SiH ) and nitrogen (N ) in a ratio of 30:100 at 400&deg; 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&deg; C., and the a-F:C dielectric layer has a dielectric constant (k) as low, or lower, than 2.5.

Method to enhance the adhesion of silicon nitride to low-k fluorinated amorphous carbon using a silicon carbide adhesion promoter layer

A method of producing a low-k interconnect dielectric material, using PECVD processes and readily available precursors to produce carbon-doped silicon oxide (SiOC). SiOC dielectric materials are produced using conventional silane based gas precursors, of silane and nitrous oxide, along with hydrocarbon gas. The use of methane and acetylene in combination with silane based gas precursors is provided. Methane produces network terminating species, specifically methyl, which replaces oxygen in an Si&mdash;O bond within a silicon dioxide network. This increases the volume, reduces the density and the dielectric constant of the material. Acetylene acts as a possible source of carbon and as a modifier, reducing or eliminating undesirable bridging species, such as carbene, or enhancing desireable network terminating species, such as methyl. Following implantation, the material is annealed to reduce the&mdash;OH and to potentially further lower the dielectric constant.

Method of making low-K carbon doped silicon oxide

A method has been provided to counteract the inherent tension in a deposited film. A wafer substrate is fixed to a wafer chuck having a curved surface. When the chuck surface is convex, a tensile stress is implanted in a deposited film. Upon release from the chuck, the deposited film develops a compressive stress. When the chuck surface is concave, a compressive stress is implanted in the deposited film. Upon release from the chuck, the deposited film develops a tensile stress. Loading a film with a compressive stress is helpful in making films having an inherently tensile stress become thermal stable. Stress loading is also used to improve adhesion between films, and to prevent warping of a film during annealing. A product-by-process using the above-described method is also provided.

Stress-loaded film and method for same

The invention provides a process for depositing fluorinated amorphous carbon (a-F:C) films on IC wafers to provide a low-k interconnect dielectric material. The process, carried out in a PECVD chamber, introduces silane gas (SiH.sub.4) into the mixture of C.sub.4 F.sub.8 and CH.sub.4 gases used to deposit a-F:C films. The silane helps to decrease the fluorine etchants in the deposited film, helping to improve the crosslinks in the deposited product. Film produced in accordance with the present invention has both low-k, generally below 2.4, and high thermal stability, generally above 440.degree. C., allowing for higher thermal anneal temperatures.

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Vancouver, WA, United States of America

Hongning Yang