LITHOGRAPHIC APPARATUS AND DEVICE MANUFACTURING METHOD
First Claim
1. A lithographic projection apparatus comprising:
- an illumination system arranged to condition a radiation beam;
a support structure configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section;
a substrate table configured to hold a substrate;
a projection system arranged to project the patterned radiation beam onto a target portion of the substrate;
a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid; and
a bubble reduction device configured to reduce a size, a concentration, or both of bubbles in the liquid, the bubble reduction device comprising a bubble detector configured to detect bubbles in the liquid.
1 Assignment
0 Petitions
Accused Products
Abstract
A lithographic apparatus and device manufacturing method makes use of a liquid confined in a reservoir between the projection system and the substrate. Bubbles forming in the liquid from dissolved atmospheric gases or from out-gassing from apparatus elements exposed to the liquid are detected and/or removed so that they do not interfere with exposure and lead to printing defects on the substrate. Detection may be carried out by measuring the frequency dependence of ultrasonic attenuation in the liquid and bubble removal may be implemented by degassing and pressurizing the liquid, isolating the liquid from the atmosphere, using liquids of low surface tension, providing a continuous flow of liquid through the imaging field, and/or phase shifting ultrasonic standing-wave node patterns.
-
Citations
21 Claims
-
1. A lithographic projection apparatus comprising:
-
an illumination system arranged to condition a radiation beam; a support structure configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section; a substrate table configured to hold a substrate; a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid; and a bubble reduction device configured to reduce a size, a concentration, or both of bubbles in the liquid, the bubble reduction device comprising a bubble detector configured to detect bubbles in the liquid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A lithographic projection apparatus comprising:
-
an illumination system arranged to condition a radiation beam; a support structure configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section; a substrate table configured to hold a substrate; a projection system arranged to project the patterned radiation beam onto a target portion of the substrate; a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid; and a detection system configured to detect impurities in the liquid, including a light source, a light detector and a light comparator, the light source and the light detector being arranged so that light emitted by the source propagates between the source and the detector through a portion of the liquid, the comparator being arranged to detect changes in the proportion of the emitted light that arrives at the detector after propagation through a portion of the liquid.
-
-
21-40. -40. (canceled)
Specification