Degradation of the Au₄Al compound in gold ballbonds during isothermal aging in air at 175 °C

Assessing Au-Al wire bond reliability using integrated stress sensors

“…In [18], shear and pull strengths of bonds aged at 175° over 1000 h are measured. Shear strength increases up to 200 h and then decreases.…”

“…Since negligible current passes through the wires measuring the voltage due to the high resistance of the volt meter, only the bond resistance is measured. Existing literature offers cases where the contact resistance is measured at discrete intervals using probes to obtain a 4-wire measurement [18]. A double ball bond can be used to measure contact resistance where a second Au ball is bonded directly on top of a test bond to provide for the V H , I H measurements, and a custom test chip is equipped with V L , I L measurements [4] as shown in Fig.…”

Corrosion of Gold and Copper Ball Bonds

“…The results generally show that gold ball bonds are not as susceptible to oxidation/corrosion effects as copper ball bonds. However, the sheared gold ball in Figure 3(a) shows evidence of intermetallic oxidation around the periphery, a conclusion that is drawn based on previous publications that showed this failure mode [14][15][16]. The Au 4 Al based intermetallic (which may contain other elements from the bond pad) can oxidise under dry conditions such that Al forms an oxide film and Au is precipitated.…”

“…Boettcher et al [13] concluded that moisture had little effect on CuAl 2 and corroded or oxidised CuAl and primarily Cu 9 Al 4 and that when the latter compounds degraded, an amorphous Al oxide formed over CuAl 2 that remained adhered to the bond pad. The Al oxide layer contained Cu precipitates and the microstructure seen in Figure 4 of Boettcher et al [13] resembles the microstructure of Au precipitates and Al oxide in references [14][15][16] that formed under dry conditions, which is due to selective (internal) oxidation of Al and precipitation of Au. Oxidation of Al in bulk intermetallics [18] and precipitation of Au in thin films of Au-Al intermetallics has been observed [19,20] and generally occurs in aluminide compounds [21][22][23].…”

Surface Topographical Characterization of Gold Aluminide Compound for Thermosonic Ball Bonding

“…With time and temperature the gold aluminide compounds continues to growth and will even proceed under ambient conditions [4]. Therefore, thermal aging is widely used as a screening test to determine the reliability of the gold ball bonds [5][6][7].…”