Properties of metal interconnects and metallization selection for ICs

Properties of Metal Interconnects and Metallization Selection for ICs
- Practical Electron Microscopy and Database -
- An Online Book -

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Depending on the technology and applications in integrated circuits (ICs), the selection of materials for metallization can be different. Table 2012a lists the general selections for different applications.

Table 2012a. Metallization selections in ICs.

Application	Selection
Gates, interconnection, and contacts	Polysilicon, refractory metal silicides (e.g. MoSi_x, TaSi_x, WSi_x, and TiSi_x), nitrides,aluminum, copper, and/or refractory metals.
Diffusion barrier layer	Ti, TiN, Ta, TaN, Ti-W alloy, and/or silicides
Top level	Aluminum, and/or copper
Metallization on silicon	Silicides, tungsten, aluminum, and/or copper

Table 2012b. Properties of metal interconnects.

	Cu	Al	Au	Ag	W
Corrosion resistance	Poor	Good	Excellent	Poor	Good
Adhesion to SiO₂	Poor	Good	Poor	Poor	Poor
Electromigration resistance	High	Low	Very high	Low	Very high

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