Properties of Metallizations Used in Semiconductor Manufacturing

Metallizations Used in Semiconductor Manufacturing

Semiconductor devices employ metallizations primarily to serve as a means of electrical contact and interconnection within the die circuits. Thin-film aluminum is the most widely used metallization in semiconductor manufacturing because of its many desirable properties, but there are many other metals or alloys used for the same purpose. Table 1 shows examples of such metals and alloys along with some of their properties.

The last column of Table 1 pertains to the critical temperature beyond which the metallization on silicon becomes unstable in one of several ways: further reaction with silicon, decomposition, agglomeration, or mechanical failure. These temperatures were determined either by experimentation or experience within the industry.

Table 1. Properties of Metallizations Used in Integrated Circuits

Metal/Alloy	Resistivity (µΩ-cm)	Melting Temp. (deg C)	CTE (ppm/deg C)	Reaction Temp with Silicon (deg C)	Max. Temp. Stable on Si (deg C)
Al	2.7-3.0	660	-	~250	~250
M	6-15	2620	5	400-700	~400
W	6-15	3410	4.5	600-700	~600
MoSi₂	40-100	1980	8.25	-	>1000
TaSi₂	38-50	~2200	8.8-10.7	-	>=1000
TiSi₂	13-16	1540	12.5	-	>=950
WSi₂	30-70	2165	6.25-7.9	-	>=1000
CoSi₂	10-18	1326	10.14	-	<=950
NiSi₂	~50	993	12.06	-	<=850
PtSi	28-35	1229	-	-	<=750
Pt₂Si	30-35	1398	-	-	<=700
HfN	30-100	~3000	-	450-500	450
ZrN	20-100	2980	-	450-500	450
TiN	40-150	2950	-	450-500	450
TaN	~200	3087	-	450-500	450
NbN	~50	2300	-	450-500	450
TiC	~100	3257	-	450-500	450
TaC	~100	3985	-	-	-
TiB₂	6-10	-	-	>600	>600

Reference: Sze, "VLSI Technology", McGraw Hill

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LINKS: Metallization; Thin Films; Ohmic Contacts

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