Die shear strength as a function of bond frame geometry — Au-Au thermo-compression bonding

The die shear strength has been studied as a function of bond frame geometry for wafer-level Au-Au thermo-compression bonds. The shear strength of samples with a 100 and 200 μm wide bond frame (bond area 1–2 mm²) was higher and more uniform than that of samples with a 400 μm wide bond frame (bond area 4 mm²). Bond frames with rounded corners had higher bond strength than samples with right angled corners (strength increased by 10–20 %). Three different fracture modes were observed. These trends were supported by finite element analysis (FEA) simulations. Conservative bonding parameters (temperature ≥ 400 °C, time ≥ 15 min, pressure 21 MPa) were applied to assure a uniform bond quality for the inspected samples. Shear testing as a method to quantify bond strength was discussed in general and in particular with respect to observed effects of bond frame geometries.