Patent ID: 7746447

Claim:
A lithographic apparatus for projecting an image of a desired pattern through a liquid onto substrates, the apparatus comprising: a plurality of substrate holders, each substrate holder being arranged to hold at least one substrate and having a conduit therein for passing a temperature control fluid; a fluid supply system arranged to supply temperature control fluid substantially at a predetermined temperature; a flow controller arranged to control the rates of flow of temperature control fluid in each of the substrate holders so that the flow rate in a first one of the substrate holders is different from the flow rate in a second one of the substrate holders; and a temperature control system arranged between the fluid supply system and the substrate holders when a respective substrate holder is in position to hold the substrate during projection of the image through the liquid, the temperature control system comprising a heater arranged to heat the temperature control fluid; a first temperature sensor arranged to measure the temperature of the temperature control fluid entering the respective substrate holder, a second temperature sensor arranged to measure the temperature of the temperature control fluid exiting the respective substrate holder, and a temperature controller arranged to receive temperature measurements from the first temperature sensor and the second temperature sensor and to control the heater based on the temperature measurements.