Lithographic apparatus, substrate and device manufacturing method

• US 9,563,131 B2
• Filed: 11/06/2015
• Issued: 02/07/2017
• Est. Priority Date: 04/16/2012
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Quintanilha, Richard
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US14/934,734
• Publication Number:
  US 20160062247A1
• Time in Patent Office: 459 Days
• Field of Search: 355/52, 355/53, 355/55, 355/67, 356/237.2, 356620-624
• US Class Current: 1/1
• CPC Class Codes: G01N 21/93 Detection standards; Calibrating baseline adjustment, drift correction
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
• CPC Class Codes: G03F 7/70308 Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift
• CPC Class Codes: G03F 7/70641 Focus
• CPC Class Codes: G03F 7/70683 Mark designs

Abstract

A method uses a lithographic apparatus to form an inspection target structure upon a substrate. The method comprises forming the periphery of the inspection target structure so as to provide a progressive optical contrast transition between the inspection target structure and its surrounding environment. This may be achieved by providing a progressive change in the optical index at the periphery of the target structure.

Claims

1. A lithographic apparatus comprising:

an illumination system configured to condition a radiation beam;

a support configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;

a substrate table configured to hold the substrate; and

a projection system configured to project the patterned radiation beam onto a target portion of the substrate,

wherein the lithographic apparatus is configured to form upon the substrate an inspection target structure, a periphery of the inspection target structure being formed so as to provide a progressive optical contrast transition between the inspection target structure and its surrounding environment.

2. The lithographic apparatus of claim 1, wherein the progressive optical contrast transition is provided by providing a progressive change in the optical index at the periphery of the target structure.

3. The lithographic apparatus of claim 2, wherein that progressive optical contrast transition is provided by providing an outermost element along one or more of the target structure'"'"'s peripheral edges, the height of the element decreasing towards the peripheral edge.

4. The lithographic apparatus of claim 3, wherein the outermost element is made wider than the other elements of which the target structure is comprised.

5. The lithographic apparatus of claim 2, wherein:

the progressive optical contrast transition is provided by providing peripheral elements along one or more of the target structure'"'"'s peripheral edges; and

along any one peripheral edge, the optical index of each peripheral element differs progressively toward the peripheral edge.

6. The lithographic apparatus of claim 5, wherein:

the peripheral elements are lines; and

along any one peripheral edge, the line width of each line decreases progressively toward the peripheral edge.

7. The lithographic apparatus of claim 5, wherein:

the peripheral elements are broken lines; and

along any one peripheral edge, the ratio of line element to line break for each broken line decreases progressively toward the peripheral edge.

8. The lithographic apparatus of claim 1, wherein the patterning device includes an alteration to compensate for image errors due to diffraction.

9. The lithographic apparatus of claim 1, wherein the inspection target is smaller than about 12 μ

m along any edge.