Abstract A method for isolating interdigitated metal contacts for rear contact solar cells using aerosol-printed polymer masking lines which can “lift off” overlying metal during a sonication step is described. Aluminum lift-off is demonstrated with masking lines formed by aerosol-printed novolac resin and polyacrylic acid. By printing novolac resin lines that are ∼10 μm high, lift-off of evaporated aluminum in an ultrasonic bath reliably resulted in 100 to 170 μm isolation gaps being formed between n-type and p-type rear contacts on different wafer surfaces. Performing this lift-off process using water-soluble polyacrylic acid lines may be advantageous due to the less expensive recovery of lift-off metal from the sonication bath.