Lithographic Apparatus and Device Manufacturing Method

• US 20090263734A1
• Filed: 06/29/2009
• Published: 10/22/2009
• Est. Priority Date: 08/30/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: MULKENS, Johannes Catharinus Hubertus, Munnig Schmidt, Robert-Han
• Granted Patent: US 8,259,289 B2
• Time in Patent Office: Days
• US Class Current: 430/22
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041

Abstract

In optical maskless lithography, scanning of a single substrate is typically much slower than in conventional lithography. Solutions are described for the adoption of immersion lithography techniques into optical maskless lithography and in particular provides one or more solutions to reduce the amount of time which the immersion liquid is in contact with any given part of the top surface of the substrate during imaging.

Claims

1. A lithographic projection apparatus, comprising:

an array of individually controllable elements configured to modulate a cross-section of a radiation beam;

a projection system configured to project the modulated radiation beam onto a target portion of a substrate; and

a liquid supply system configured to provide a liquid to a space between the projection system and the substrate, the liquid supply system comprising;

a lower part configured to supply liquid to and remove liquid from a top surface of the substrate, and

an upper part to supply liquid to and remove liquid from the remainder of the space, wherein there is a step change in cross-sectional area, in a plane substantially perpendicular to a direction of propagation of the beam, to which liquid is supplied between the upper and lower parts.

2. The apparatus of claim 1, further comprising a controller configured to control a supply of liquid from the lower part to be substantially at such a rate that, in use, scanning movement of the substrate is effective to transport the liquid to an outlet without the need for a pump or low pressure source.

3. The apparatus of claim 1, wherein the upper part is configured to provide liquid to the space in a direction substantially perpendicular to the direction of propagation.

4. The apparatus of claim 1, wherein the lower part is configured to provide liquid in a direction with a component towards the substrate.

5. A device manufacturing method, comprising:

projecting a modulated beam of radiation onto a substrate through a liquid on a top surface of the substrate;

moving the substrate in a first direction; and

continuing the projecting and moving until an edge of an area to be imaged is imaged.

6. The method of claim 5, further comprising covering the top surface of the substrate with a liquid after the edge of the area is imaged, but prior to further continuing the projecting and moving.

7. The method of claim 6, wherein the covering the top surface of the substrate is performed at least every 600 seconds.

8. The method of claim 6, further comprising, after covering the top surface of the substrate, performing the projecting, moving, and continuing in a second direction which is in an axis different to, but substantially parallel to, the axis on which the projecting, moving, and continuing were previously performed.

9. A device manufacturing method, comprising:

projecting a modulated beam of radiation onto a substrate through a liquid on a localized area of a top surface of the substrate; and

after the projecting, covering the top surface of the substrate in liquid prior to again projecting the modulated beam of radiation, onto the substrate, through liquid on a localized area of the top surface of the substrate.

10. The method of claim 9, further comprising measuring the substrate after the covering and before the again projecting.

11. The method of claim 9, wherein the liquid through which the beam of radiation passes is the same type of liquid as is used to cover the substrate.

12. The method of claim 9, wherein the top surface is covered in liquid at least once every 600 seconds.

13. The method of claim 9, wherein the projecting and covering occur one after another in a loop until all the desired area of the top surface has been irradiated by the modulated beam.