US 8,796,652 B2 · Laser sustained plasma bulb including water

Abstract

A wafer inspection system includes a laser sustained plasma (LSP) light source that generates light with sufficient radiance to enable bright field inspection. Reliability of the LSP light source is improved by introducing an amount of water into the bulb containing the gas mixture that generates the plasma. Radiation generated by the plasma includes substantial radiance in a wavelength range below approximately 190 nanometers that causes damage to the materials used to construct the bulb. The water vapor acts as an absorber of radiation generated by the plasma in the wavelength range that causes damage. In some examples, a predetermined amount of water is introduced into the bulb to provide sufficient absorption. In some other examples, the temperature of a portion of the bulb containing an amount of condensed water is regulate to produce the desired partial pressure of water in the bulb.

Claims20

Dependent claims

A laser sustained plasma light source, comprising:

a laser operable to generate an amount of illumination light;
and
a plasma bulb having at least one wall operable in part to contain a working gas and an amount of water, wherein the illumination light generated by the laser is incident on the working gas and generates a laser sustained plasma emission, wherein a portion of the laser sustained plasma emission is absorbed by the water without being incident on the at least one wall of the bulb.

Dependencies are inferred from the claim text.

Laser sustained plasma bulb including water

Life of this patent

Laser sustained plasma bulb including water

Life of this patent

Abstract

Claims20