A wafer level HBM tester delivering pulses with variable risetime through transmission lines

In current HBM wafer level testers long wires between pulse generating circuits and the wafer probe needles distort the HBM waveform. A novel HBM equivalent circuit utilizing constant impedance transmission lines in combination with individual lumped RC-elements close to each pin of the DUT can generate stress pulses with high quality and even variable risetimes. The new concept and its performance and limitations for an HBM tester are discussed.