Advanced Micro Devices Corporation

Globalfoundries Inc.

Bernd Schulz

Thomas Werner

Gunter Grasshoff

Carsten Hartig

Uwe Schulze

Rolf Seltmann

Fritjof Hempel

By taking into consideration tool-specific distortion signatures and reticle-specific placement characteristics in an alignment control system, the control quality of sophisticated APC strategies may be significantly enhanced. Respective correction data may be established on the basis of any combinations of tool/reticles and layers to be aligned to each other, which may modify the respective target values of alignment parameters used for controlling the alignment process on the basis of standard overlay measurement data obtained from dedicated overlay marks.

Method and system for reducing overlay errors within exposure fields by APC control strategies

An enhanced technique for determination of an alignment accuracy involves an overlay target assembly which comprises at least two targets, each target having a first sub-structure of a first layer and a second sub-structure of a second layer, wherein, when the first layer and the second layer are correctly aligned, the first sub-structure and the second sub-structure of at least one of the targets are offset with respect to each other by a programmed offset and the overlay target assembly is invariant to at least one geometric transformation. If the offset vectors which describe the offset between the first sub-structure and the second sub-structure all have the same norm, the overlay error may be determined without calibration. Redundancy may be increased by providing each target with two or more programmed offsets between elements of the first sub-structure and elements of the second sub-structure.

Structure and method for determining an overlay accuracy

The present invention provides a technique for obtaining overlay error and PPE error information from a single measurement structure. This is accomplished by forming periodic sub-structures in at least two different device layers in a single measurement structure, wherein at least one segmented and one non-segmented portion is provided in the two different device layers.

Structure and method for simultaneously determining an overlay accuracy and pattern placement error

A two-dimensional periodic pattern that is symmetrical with respect to a first and a second direction allows the determination of an overlay accuracy that is obtained during the fabrication of the two-dimensional structure. Due to the symmetry of the structure, the overlay accuracy in the first direction may be determined on the basis of substantially the same reference data as used for the determination of the overlay accuracy of the second direction so that establishing libraries is simplified. Moreover, depending on the capability of the metrology tool, the overlay accuracy in both directions may be obtained simultaneously.

Two-dimensional structure for determining an overlay accuracy by means of scatterometry

An apparatus for obtaining information on critical dimensions and overlay accuracy of features in a semiconductor structure comprises a light source, a detector and an optical means defining a first optical path and a second optical path. The first optical path and the second optical path are oriented in correspondence with the respective orientations of diffracting patterns provided on the semiconductor structure to obtain the required information without the necessity of rotating the semiconductor structure. This insures a significantly higher throughput.

Apparatus for determining an overlay error and critical dimensions in a semiconductor structure by means of scatterometry

A scatterometer system comprises a pitch calibration station that allows the monitoring of a tool status of the scatterometry system without involving a user's interaction. The pitch calibration station comprises a pitch calibration standard, for example in the form of a grid pattern that may conveniently be evaluated on the basis of a reference data library. By providing the pitch calibration station, the measurement process may easily be adapted to include reference measurements on a regular basis so as to increase the reliability of measurement values obtained by scatterometry. In one particular example, a corresponding set of instructions for performing the calibration measurement may be implemented into a self-test routine of the scatterometry system.

Scatterometer including an internal calibration system

A semiconductor structure and a method of determining an overlay error produced during formation of a semiconductor structure is disclosed. The semiconductor structure comprises a first periodic pattern and a second periodic pattern, which overlap with each other, wherein a relative position between the overlapping first and second periodic patterns contains information on the magnitude and the sign of an overlay error in a predefined direction that has been caused during the formation of the first and second periodic patterns. The overlay error is determined by directing a light beam of known optical properties onto the first and second periodic patterns and by analyzing the diffracted beam by comparison with reference data. By providing two differently oriented diffracting areas, each comprising first and second periodic patterns, the overlay error in two dimensions can be determined.

Semiconductor structure and method for determining critical dimensions and overlay error

A semiconductor structure and a method of determining an overlay error produced during formation of the semiconductor structure are disclosed. The semiconductor structure comprises a first two-dimensional periodic pattern and a second two-dimensional periodic pattern, which overlap with each other, wherein a relative position between the overlapping first and second two-dimensional periodic patterns indicates the magnitude and direction of an overlay error caused during the formation of the first and second two-dimensional periodic patterns. The semiconductor allows one to independently determine the overlay errors in linearly independent directions by directing a light beam of known optical properties onto the first and second two-dimensional periodic patterns and by analyzing the diffracted beam by comparison with reference data.

A semiconductor device structure comprises a corner structure enclosed by a delineation region, wherein the shape of the corner structure does not exhibit any symmetry with respect to point symmetry and axial symmetry, such that the corner structure is unambiguously recognizable by an automated alignment system. Furthermore, the inner region of the corner structure may be filled with a pattern indicating the type of material layer in which the corner structure is formed. The corner structure exhibits a strong contrast even if the wafer is subjected to a CMP treatment.

Growing community of inventors

Radebeul, Germany

Bernd Schulz