The double resonator technique for simultaneous thin film areal mass density and integrated lateral stress measurements will be reviewed. The technique is applied to the measurement of the sputtering yield of 45-keV Kr onto Au. The compressive stress buildup in the Au and the change in sputtering yield from 16 to 26 atoms/ion as the accumulated Kr fluence loads the Au substrate are demonstrated. The errors arising in the use of single resonator microbalances from the compressive stress buildup are shown to be of the order of 10%–25% for sputtering yield measurements at low-to-medium ion fluences where substrate loading occurs.