| 摘要 |
The present invention relates to a method of protecting a radiation source producing extreme ultraviolet radiation (EUV) and/or soft X-rays against short circuits. The method applies to radiation sources producing said EUV-radiation and/or soft X- rays by means of an electrically operated discharge, which is ignited in a vapor between at least two electrodes (1, 2) in a discharge space, wherein said vapor is produced from a metal melt (6), which is applied to a surface in said discharge space and at least partially evaporated by an energy beam (9). Such a radiation source has one or several small gaps (17) between said electrodes (1, 2) and/or between components (4, 5) electrically connected to said electrodes (1, 2). These gaps (17) can cause short circuits when evaporated metal condenses there. In the present method during operation of the radiation source at least one surface bordering said gaps (17) and/or one or several protective elements (16, 18) covering said gaps (17) or arranged inside said gaps (17) are heated to a temperature at which the vapor pressure of said metal is high enough to evaporate metal material condensed on said surface or protective elements. With the present method the lifetime of the radiation source is extended. |
