A method of operating a semiconductor apparatus includes generating, by a droplet generator, a target material droplet; receiving, by a catcher, the target material droplet, wherein the catcher has a first section and a second section, wherein the first section of the catcher is closer to the droplet generator than the second section of the catcher; and heating the second section of the catcher, wherein the first section of the catcher is longer than the second section of the catcher and is free of a heater, and heating the second section of the catcher is performed such that a temperature of the second section of the catcher is higher than a temperature of the first section of the catcher.