US 7,612,882 B2Granted

Optical gratings, lithography tools including such optical gratings and methods for using same for alignment

AssigneeHewlett-Packard Development Company, L.P.

InventorsWei Wu, Warren Robinett, Shih-Yuan Wang, Jun Gao, Zhaoning Yu

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Abstract

Lithography tools and substrates are aligned by generating geometric interference patterns using optical gratings associated with the lithography tools and substrates. In some embodiments, the relative position between a substrate and lithography tool is adjusted to cause at least one geometric shape to have a predetermined size or shape representing acceptable alignment. In additional embodiments, Moiré patterns that exhibit varying sensitivity are used to align substrates and lithography tools. Furthermore, lithography tools and substrates are aligned by causing radiation to interact with optical gratings positioned between the lithography tools and substrates. Lithography tools include an optical grating configured to generate a portion of an interference pattern that exhibits a sensitivity that increases as the relative position between the tools and a substrate moves towards a predetermined alignment position.

Claims27

Dependent claims

A method of aligning a lithography tool with a substrate, the method comprising:

providing a substrate having at least one substrate alignment feature comprising a first optical grating, wherein the first optical grating is configured to have a plurality of alternating light and dark regions;
providing a lithography tool having at least one tool alignment feature comprising a second optical grating, wherein the second optical grating is configured to have a plurality of alternating light and dark regions, the first optical grating and the second optical grating being configured to generate a Moiré pattern in a beam of electromagnetic radiation when the beam of electromagnetic radiation interacts with both the first optical grating and the second optical grating, the sensitivity of the Moiré pattern varying with the relative alignment between the substrate and the lithography tool;
configuring the alternating light and dark regions of both the first optical grating and the second optical grating to have at least one of a width, a pitch, and a duty cycle that varies across each respective optical grating;
positioning the lithography tool relative to the substrate and roughly aligning the tool alignment feature and the substrate alignment feature;
causing a beam of electromagnetic radiation to interact with both the first optical grating and the second optical grating to generate a Moiré pattern;
and
adjusting the relative position between the substrate and the lithography tool to cause the Moiré pattern to approximate or match a predetermined pattern representing an acceptable degree of alignment between the lithography tool and the substrate.

4 more elements

A method of aligning a lithography tool with a substrate, the method comprising:

providing a substrate having at least one substrate alignment feature including a first optical grating;
providing a lithography tool having at least one tool alignment feature including a second optical grating, the first optical grating and the second optical grating being configured to generate an interference pattern in a beam of electromagnetic radiation when the beam of electromagnetic radiation is caused to interact with both the first optical grating and the second optical grating;
positioning the lithography tool relative to the substrate and roughly aligning the tool alignment feature and the substrate alignment feature;
causing a beam of electromagnetic radiation to interact with both the first optical grating and the second optical grating to generate an interference pattern comprising a plurality of geometric shapes;
and
adjusting the relative position between the substrate and the lithography tool to cause at least one geometric shape of the interference pattern to have at least one of a predetermined size and a predetermined shape representing an acceptable degree of alignment between the lithography tool and the substrate,
wherein adjusting the relative position between the substrate and the lithography tool comprises adjusting the relative position between the substrate and the lithography tool to cause at least one generally triangular shape of the interference pattern to have at least one of a predetermined size and a predetermined shape.

4 more elements

A method of aligning a lithography tool with a substrate, the method comprising:

roughly aligning a lithography tool with a substrate;
passing a beam of electromagnetic radiation between the lithography tool and the substrate without passing through the lithography tool or the substrate;
causing the beam of electromagnetic radiation to interact with both a first optical grating coupled to the substrate and a second optical grating coupled to the lithography tool to generate an interference pattern;
and
adjusting a relative position between the substrate and the lithography tool to cause the interference pattern to approximate or match a predetermined pattern representing an acceptable degree of alignment between the lithography tool and the substrate.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/584,461Filed 20 Oct 2006
Published: US 2008/0094629 A124 Apr 2008
Granted: 3 Nov 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G03F 9/7049
For microlithography: technique, e.g. interferometric
G03F 9/7003
For microlithography: alignment type or strategy, e.g. leveling, global alignment
G03F
Photomechanical production of textured or patterned surfaces

Family

US 2008/0094629 A1Pre-grant publication · published 24 Apr 2008
US 7,612,882 B2This patent

From the US filing history. Foreign family members aren’t listed.

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