Fast temperature cycling and electromigration induced thin film cracking in multilevel interconnection: experiments and modeling

Low-cycle fatigue of multilayer metal stack employed as fast wafer level monitor for backend integrity in smart power technologies

“…Typically this regime may well be modelled through Coffin-Manson like approach [2,9] or extended models like Norris-Landzberg ansatz [13]. We find that a modified Norris-Landzberg based ansatz, typically used for a lowcycle fatigue based failure mechanism, fits mean number of pulses to failure well for both technologies:…”

“…Each switching cycle can involve a millisecond power pulse leading to a pronounced local temperature excursion in the driver stage. A strong lateral temperature gradient imposes severe stress on the IC backend structures due to the mismatch of the coefficient of thermal expansion of aluminum or copper metals and dielectrics which may cause degradation and IC failure in respective applications [1,2,3,4,5]. Compared to vertical discrete power devices, where cyclic thermomechanical stress leads to pronounced aging of the usually thicker top aluminum metal layer itself [6], for smart-power IC products additional failure channels are present related to dielectrics and various interfaces in the fine-combed multifinger metal stack.…”

Crystal-plasticity based thermo-mechanical modeling of Al-components in integrated circuits

“…Various types of damage occur. Two crucial effects are roughening of the contacting plate, which reduces the adhesion to bond contacts as reported in [3,4], and the raise of stresses in the interlayer dielectric (ILD), which finally lead to crack initiation that can result in short circuits and failure of the assembly [4][5][6][7][8][9][10][11].…”

“…Surface roughening of (thin) metal films during plastic deformation is a common phenomenon [11][12][13][14][15]. There are different attempts to capture this effect via simulation.…”

Investigation of smart power DMOS devices under repetitive stress conditions using transient thermal mapping and numerical simulation

“…Thermal cycling during switching operation can cause gradual degradation of top metallization due to thermo-mechanical stress [4,5]. Repetitive clamping during short-circuited load operation beyond the safe operating area can also cause the thermal breakdown in the silicon active area and fatal device failure [3,7].…”