Stress migration phenomena in narrow copper lines

Stress migration (SM) behavior in narrow lines is investigated in detail using different kinds of test patterns. The characteristic of 0.14mum wide line SM failure is different from that of wider line SM failure. The failure rate in the minimum 0.14mum wide line is more than that in 0.2-0.42mum wide lines. The Weibull shape parameter "m" is about 5 in the case of 0.14mum wide line SM failure, in another case they are around 1.4 to 3. Process dependence is also different. These results of the test patterns with different VIA arrangements clarified that the contact between VIA bottom and upper edge in M1 line plays an important role in SM phenomena in narrow copper lines