Interconnect failure due to cyclic loading

Abstract

The damage generated by AC currents at 100 Hz in interconnects has been studied and compared with mechanical fatigue damage in thin films. The nature of the damage under the two loading conditions is qualitatively similar, supporting the idea that the AC current damage comes from mechanical cycling due to temperature swings on the order of 100 K from Joule heating in the interconnects. In both cases, the damage forms as surface wrinkles within single grains grow in amplitude and extent with time. The possible threat to the reliability of microelectronic and microelectromechanical systems is further escalated by the observation that soft encapsulation layers do nothing to retard the formation of the damage.

Spatially and temporally resolved thermal imaging of cyclically heated interconnects by use of scanning thermal microscopy

“…The calibration device consisted of both a resistive heater and a fourpoint resistance sensor shown in Figure 2. The device was designed to maintain a constant sensor temperature between the sensor voltage taps as previous FEA work and observations have shown that line temperatures vary at the ends of some interconnect structures (Keller et al, 2002). The small resistive heater and sensor provided a calibration source of comparable size and power output to the structure of interest, which as previously discussed is important when using a Wollaston probe at high temperatures.…”

“…Finite element analysis (FEA) (Keller et al, 2002) and observations of damage development during testing suggest that temperature in the lines is not uniform. The line resistivity method of temperature measurement does not capture local temperature variation, and hence, we seek local measurements of temperature as a function of position to better characterize the strain state induced during testing.…”

“…The new measurement technique, described elsewhere (Keller et al, 2002;Mönig et al, 2004), imposes strains in patterned metal lines adhered to Si substrates through mismatched coefficients of thermal expansion between the lines and the substrate. Knowledge of the spatial-and timeresolved thermal state of the test line provides information about the strain distribution in the specimens, a key factor in the test method.…”

Numerical simulation of fatigue behavior of flexible metal films in multiphysics fields

“…Some studies showed that the effect of temperature field on the fatigue properties of metal films could be attributed to the thermal expansion mismatch in the film and the substrate. 23,37 The thermal strain Δε T can be expressed as 23,38 Δε…”

Thermally Induced Mechanical Stress in the Stator Windings of Electrical Machines

“…The failure of copper through silicon vias due to the thermally induced mechanical stress has been presented in References [10,11]. Mechanical deformations in electric interconnects due to thermal expansion mismatch has been reported in References [12,13]. The effects of the thermally induced mechanical stresses on light emitting diodes, plastic ball grid arrays and field-programmable gate arrays are studied and discussed in References [14][15][16].Similar studies on the effect of thermally induced stress on different composite and cement-based materials have also been reported in literature.…”