Kla-Tencor Technologies Corporation

Boris Golovanesky

Michael E Adel

Ady Levy

Walter Dean Mieher

Ian R Smith

Michael Friedmann

Mark Ghinovker

Anatoly Fabrikant

Christopher F Bevis

John Fielden

Noah Bareket

Dan Wack

Kenneth P Gross

Piotr S Zalicki

Paola Dececco

Thaddeus Gerard Dziura

Moshe Baruch

Noam Knoll

Disclosed are apparatus and methods for determining overlay between a plurality of first structures in a first layer of a sample and a plurality of second structures in a second layer of the sample. Targets A, B, C and D that each include a portion of the first and second structures are provided. The target A is designed to have an offset Xa between its first and second structures portions; the target B is designed to have an offset Xb between its first and second structures portions; the target C is designed to have an offset Xc between its first and second structures portions; and the target D is designed to have an offset Xd between its first and second structures portions. Each of the offsets Xa, Xb, Xc and Xd is different from zero, and Xa is an opposite sign and differ from Xb.

Apparatus and methods for detecting overlay errors using scatterometry

Disclosed is a combined scatterometry mark comprising a scatterometry critical dimension (CD) or profile target capable of being measured to determine CD or profile information and a scatterometry overlay target disposed over the scatterometry CD or profile target, the scatterometry overlay target cooperating with the scatterometry CD or profile target to form a scatterometry mark capable of being measured to determine overlay.

Disclosed is a method for determining an overlay error between at least two layers in a multiple layer sample. An imaging optical system is used to measure a plurality of measured optical signals from a plurality of periodic targets on the sample. The targets each have a first structure in a first layer and a second structure in a second layer. There are predefined offsets between the first and second structures. A scatterometry overlay technique is then used to analyze the measured optical signals of the periodic targets and the predefined offsets of the first and second structures of the periodic targets to thereby determine an overlay error between the first and second structures of the periodic targets.

Disclosed is a method of determining an overlay error between two layers of a multiple layer sample. For a plurality of periodic targets that each have a first structure formed from a first layer and a second structure formed from a second layer of the sample, an optical system is employed to thereby measure an optical signal from each of the periodic targets. There are predefined offsets between the first and second structures. An overlay error is determined between the first and second structures by analyzing the measured optical signals from the periodic targets using a scatterometry overlay technique based on the predefined offsets.

Disclosed are techniques, apparatus, and targets for determining overlay error between two layers of a sample. In one embodiment, a method for determining overlay between a plurality of first structures in a first layer of a sample and a plurality of second structures in a second layer of the sample is disclosed. Targets A, B, C and D that each include a portion of the first and second structures are provided. Target A is designed to have an offset Xa between its first and second structures portions; target B is designed to have an offset Xb between its first and second structures portions; target C is designed to have an offset Xc between its first and second structures portions; and target D is designed to have an offset Xd between its first and second structures portions. Each of the offsets Xa, Xb, Xc and Xd is preferably different from zero; Xa is an opposite sign and differ from Xb; and Xc is an opposite sign and differs from Xd. The targets A, B, C and D are illuminated with electromagnetic radiation to obtain spectra S, S, S, and Sfrom targets A, B, C, and D, respectively. Any overlay error between the first structures and the second structures is then determined using a linear approximation based on the obtained spectra S, S, S, and S.

Disclosed is a method of determining an overlay error between two layers of a multiple layer sample. For a plurality of periodic targets that each have a first structure formed from a first layer and a second structure formed from a second layer of the sample, an interferometer is employed to modulate substantially a plurality of wavelengths of a broadband source and then acquiring one or more images of the periodic targets. There are predefined offsets between the first and second structures. An overlay error between the first and second structures is then determined by analyzing the one or more acquired images from the periodic targets using a scatterometry overlay technique based on the predefined offsets.

Disclose is a combined scatterometry mark comprising a scatterometry critical dimension (CD) or profile target capable of being measured to determine CD or profile information and a scatterometry overlay target disposed over the scatterometry CD or profile target, the scatterometry overlay target cooperating with the scatterometry CD or profile target to form a scatterometry mark capable of being measured to determine overlay.

Disclosed is a method of determining an overlay error between two layers of a multiple layer sample. For each of a plurality of periodic targets that each have a first structure formed from a first layer and a second structure formed from a second layer of the sample, a first optical signal is measured using a first ellipsometer or a first reflectometer and a second optical signal is measured using a second ellipsometer or a second reflectometer. There are predefined offsets between the first and second structures. An overlay error is determined between the first and second structures by analyzing the measured first and second optical signals from the periodic targets using a scatterometry overlay technique based on the predefined offsets.

Disclosed is a method for determining an overlay error between at least two layers in a multiple layer sample. A sample having a plurality of periodic targets that each have a first structure in a first layer and a second structure in a second layer is provided. There are predefined offsets between the first and second structures. Using a scatterometry overlay metrology, scatterometry overlay data is obtained from a first set of the periodic targets based on one or more measured optical signals from the first target set on the sample. Using an imaging overlay metrology, imaging overlay data is obtained from a second set of the periodic targets based on one or more image(s) from the second target set on the sample.

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Haifa, Israel

Boris Golovanesky