On July 1st, Toshiba Corporation's Semiconductor Company and Storage Products Company consolidated to form Semiconductor & Storage Products Company.This page describes reliability information of semiconductor products.

Current

[As of April, 2011]

Electromigration is the most well known current acceleration mode and is becoming more important as a failure mechanism as devices decrease in size and become highly integrated. ^{Note 1, Note 2} The mechanism produced by electromigration is a phenomenon in which metal atoms in metallization move when current is applied. When the metal atoms move, metallization results in electrical open. The electromigration lifetime is generally expressed as the median time to failure (MTF) using the following equation.^{Note 3}

J: Current density
n: Constant related to current
E_a: Activation energy
T: Absolute temperature
k: Boltzmann's constant
A: Constant related to metallization material, structure dimentions

The DC constant current stress test is the most popular test method. Other tests available include the DC pulse current stress test, AC pulse current stress test and the DC constant voltage stress test.

The following describes the data of an electromigration experiment conducted by Toshiba.
Figure 1 shows the relationship between current density and lifetime. From this figure, it is evident that as current density gets larger, lifetime gets shorter.

This is [Figure 1 Relationship Between Electromigration Lifetime and Current Density (Example)].

Figure 1 Relationship Between Electromigration Lifetime and Current Density (Example)

Note 1: Bibliography. C.Ryu, et al.; "Effects of Texture on Electromigration of CVD Copper," Proc. IRPS (1997)
Note 2: Bibliography. S.Yokogawa, et al.; "Electromigration Induced Incubation, Drift and Threshold in Single-Damascene Copper Interconnects," Proc. IITC (2002)
Note 3: Bibliography. J.R.Black; "Electromigration Failure Modes in Aluminum Metallization for Semiconductor Devices," Proceeding of the IEEE (1969)