The present invention relates to a cost saving liquid-treatment unit (100). According to the invention, a control unit (152), which is connected to an input port of a control valve (118, 120, 122), is adapted to set, in dependence on the evaporation rate of a treatment liquid on the substrate at the given or desired temperature of the substrate and/or at the given or desired pressure of a gaseous ambient atmosphere at the substrate, a number of dispense pulses to be applied to the substrate for the liquid treatment, a respective pulse duration of individual dispense pulses, and respective dispense-interruption time spans between the individual dispense pulses. This way, the use of treatment liquid is reduced to a minimum amount, thus reducing costs for providing and cleaning treatment liquid.