copper silicide
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 442611707
| ImageFile =
| ImageSize =
| IUPACName =
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 12159-07-8
| ChemSpiderID = 29356049
| EINECS = 235-286-8
| PubChem = 6336988
| StdInChI=1S/5Cu.Si
| StdInChIKey = JUZTWRXHHZRLED-UHFFFAOYSA-N
| SMILES = [Si].[Cu].[Cu].[Cu].[Cu].[Cu]
}}
|Section2={{Chembox Properties
| Formula = Cu5Si
| MolarMass = 345.8155 g/mol
| Appearance = silver powder
| Density =
| MeltingPtC = 825
| BoilingPt =
| Solubility =
}}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| PEL = TWA 1 mg/m3 (as Cu){{PGCH|0150}}
| IDLH = TWA 100 mg/m3 (as Cu)
}}
}}
Copper silicide can refer to either {{chem2|Cu4Si}}CRC Handbook of Chemistry and Physics, 49th edition, "Physical constants of inorganic compounds" (p. B-198). or pentacopper silicide, {{chem2|Cu5Si}}.
Pentacopper silicide is a binary compound of silicon with copper. It is an intermetallic compound, meaning that it has properties intermediate between an ionic compound and an alloy. This solid crystalline material is a silvery solid that is insoluble in water. It forms upon heating mixtures of copper and silicon.
Applications
Copper silicide thin film is used for passivation of copper interconnects, where it serves to suppress diffusion and electromigration and serves as a diffusion barrier.{{cite web |url=http://www.patentstorm.us/patents/6869873.html |title=Copper silicide passivation for improved reliability - US Patent 6869873 |accessdate=2007-02-10 |url-status=dead |archiveurl=https://web.archive.org/web/20070929082943/http://www.patentstorm.us/patents/6869873.html |archivedate=2007-09-29 }}{{Better source needed|reason=The existence of a patented technology does not mean that it is used.|date=January 2019}}
Copper silicides are invoked in the Direct process, the industrial route to organosilicon compounds. In this process, copper, in the form of its silicide, catalyses the addition of methyl chloride to silicon. An illustrative reaction affords the industrially useful dimethyldichlorosilane:{{Greenwood&Earnshaw2nd}}
:2 CH3Cl + Si → (CH3)2SiCl2