Patent ID: 6815900
Filing Date: 2004-11-09
Classification: H05G

Abstract:
A radiation source for the generation of extreme ultraviolet (EUV) radiation based on a dense, hot plasma generated by gas discharge containing two electrodes which are electrically separated from one another by insulators which are resistant to breakdown and at the same time form rotationally symmetric electrode housings for parts of a vacuum chamber, comprising:a vacuum chamber; a first electrode housing and a second electrode housing provided within the vacuum chamber; a gas discharge for plasma generation being provided between said first electrode housing and second electrode housing; an outlet opening for the radiation emitted by the plasma being provided in the first electrode housing; a gas supply unit for generating a flow of working gas through the vacuum chamber; a high-voltage module for providing high-voltage pulses at the electrodes; a preionization unit for generating preionization of the working gas prior to the gas discharge triggered by the high-voltage pulse; said second electrode housing having a narrowed portion and an electrode collar which adjoins the latter and which is enclosed concentrically by the first electrode housing; a concentric insulator layer being provided in this area of concentric overlapping between the first electrode housing and the electrode collar of the second electrode housing in order to shield the concentric surface regions of the two electrode housings; said concentric insulator layer extending in the direction of the outlet opening of the first electrode to the extent that the gas discharge takes place substantially parallel to the axis of symmetry of the electrode housing; and said electrode collar being stepped radially relative to the concentric insulator layer in such a way that at least one end region of the electrode collar is at a distance from the concentric insulator layer such that a concentric gap is formed.