Lithographic apparatus, substrate and device manufacturing method

Patent metadata

Field	Value
Publication number	US-9563131-B2
Application number	US-201514934734-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Apr 16, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

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.

First claim

What is claimed is:

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 μm along any edge.

Assignees

• Asml Netherlands Bv

Inventors

• Quintanilha Richard

Classifications

• G03F1/144

  Physics · mapped topic

• G03F7/70641

  Focus · CPC title

• G01N21/956

  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 H10P74/20)} · CPC title

• G03F7/70308 Primary

  Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift · CPC title

• G01N21/93 Primary

  Detection standards; Calibrating {baseline adjustment, drift correction} · CPC title