Substrate, a method of measuring a property, an inspection apparatus and a lithographic apparatus

Patent metadata

Field	Value
Publication number	US-9229338-B2
Application number	US-200913059405-A
Country	US
Kind code	B2
Filing date	Jul 27, 2009
Priority date	Sep 8, 2008
Publication date	Jan 5, 2016
Grant date	Jan 5, 2016

Abstract

Scatterometry for measuring overlay. A second set of superimposed gratings are superposed over a first set of superimposed gratings. The second set of gratings have a different periodicity from the first set of gratings or a different orientation. Consequently the first order diffraction pattern from the second set of superimposed gratings can be distinguished from the first order diffraction pattern from the first set of superimposed gratings.

First claim

The invention claimed is:

1. A substrate comprising:
a first set of superimposed gratings and a second set of superimposed gratings, said second set of superimposed gratings in turn being superimposed over said first set of superimposed gratings, said first set of superimposed gratings having a periodicity in a first direction and said second set of superimposed gratings having a periodicity in a second direction,
wherein said first and second directions are at an angle of between 30° and 60° to each other such that within an image of respective diffraction patterns produced by radiation reflected by each of the first set of superimposed gratings and the second set of superimposed gratings, the diffraction patterns of at least one order corresponding to each of the first and second sets of superimposed gratings are spatially distinguishable from each other within said image.

2. A method of measuring a property of a substrate, said method comprising:
exposing a first grating;
exposing a second grating superimposed over said first grating to form a first set of gratings with said first grating, said first set of gratings having a periodicity in a first direction;
exposing a third grating;
exposing a fourth grating superimposed over said third grating to form a second set of gratings with said third grating, said second set of gratings having a periodicity in a second direction;
projecting radiation onto said second set of gratings;
detecting said radiation reflected by said substrate to form a detected image; and
determining said property from said reflected radiation,
wherein said second set of gratings is superimposed on said first set of gratings and said first and second directions are at an angle of between 30° and 60° to each other such that within said detected image in respective diffraction patterns produced by radiation reflected by each of the first set of superimposed gratings and the second set of superimposed gratings, the diffraction patterns of at least one order corresponding to each of the first and second sets of superimposed gratings are spatially distinguishable from each other within said image.

3. An inspection apparatus configured to measure a property of a substrate, the apparatus comprising:
a radiation projector configured to project radiation onto said substrate:
a high numerical aperture lens;
a detector configured to detect the radiation beam reflected from a surface of the substrate; and
a substrate comprising a first set of superimposed gratings and a second set of superimposed gratings, said second set of superimposed gratings being superimposed over said first set of superimposed gratings, said first set of superimposed gratings having a periodicity in a first direction and said second set of superimposed gratings having a periodicity in a second direction wherein said first and second directions are at an angle of between 30° and 60° to each other such that such that within an image of respective diffraction patterns produced by radiation reflected by each of the first set of superimposed patterns and the second set of superimposed gratings, the diffraction patterns of at least one order corresponding to each of the first and second sets of superimposed gratings are spatially distinguishable from each other within said image.

4. A substrate comprising:
a first set of superimposed gratings; and
a second set of superimposed gratings,
wherein said second set of superimposed gratings in turn being superimposed over said first set of superimposed gratings, said first set of superimposed gratings having a periodicity in a first direction and said second set of superimposed gratings having a periodicity in a second direction wherein said first and second directions are at an angle of between 30° and 60° to each other.

5. A substrate comprising:
a first set of superimposed gratings; and
a second set of superimposed gratings, the second set of superimposed gratings in turn being superimposed over the first set of superimposed gratings, the first set of superimposed gratings having a periodicity in a first direction and the second set of superimposed gratings having a periodicity in a second direction; and
a third set of superimposed gratings, the third set of superimposed gratings in turn being superimposed over the second set of superimposed gratings, the third set of superimposed gratings having a periodicity in a third direction,
wherein the first and second directions are at an angle of 60° to each other and the third direction is at an angle of 60° to the first and second directions.

Assignees

• Van De Kerkhof Marcus Adrianus
• Van Der Schaar Maurits
• Smilde Hendrik Jan Hidde
• Asml Netherlands Bv

Inventors

• Van De Kerkhof Marcus Adrianus
• Van Der Schaar Maurits
• Smilde Hendrik Jan Hidde

Classifications

• H10W46/00

  Marks applied to devices, e.g. for alignment or identification · CPC title

• G03F9/70

  for microlithography (measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775) · CPC title

• H01L2924/0002

  Electricity · mapped topic

• G03F9/7076

  Mark details, e.g. phase grating mark, temporary mark · CPC title

• G03F7/70683 Primary

  Mark designs · CPC title