Kla-Tencor Technologies Corporation

Kla Tencor Corporation

Zain Saidin

Sterling G Watson

Ady Levy

Stanley E Stokowski

Chris Mack

James Norman Wiley

Yalin Xiong

Thomas Vavul

Donald J Parker

Anthony Vacca

Carl Hess

Christophe Fouquet

Lance Glasser

Moshe E Preil

Ellis Chang

John Charles Robinson

Amir Widmann

Frank Laske

Stan Stokowski

Dongsub Choi

Larry Steven Zurbrick

Savitha Nanjangud

Gordon Abbott

Sergio Edelstein

Various systems and methods for detecting design and process defects on a wafer, reviewing defects on a wafer, selecting one or more features within a design for use as process monitoring features, or some combination thereof are provided. One system is configured to detect design defects and process defects at locations on a wafer at which images are acquired by an electron beam review subsystem based on defects in a design, additional defects in the design, which are detected by comparing an image of a die in the design printed on the wafer acquired by the electron beam review subsystem to an image of the die stored in a database, and defects detected on the wafer by a wafer inspection system.

System and method for detecting design and process defects on a wafer using process monitoring features

A combined metrology mark, a system, and a method for calculating alignment on a semiconductor circuit are disclosed. The combined metrology mark may include a mask misregistration structure and a wafer overlay mark structure.

Unique mark and method to determine critical dimension uniformity and registration of reticles combined with wafer overlay capability

Various methods, designs, defect review tools, and systems for determining locations on a wafer to be reviewed during defect review are provided. One computer-implemented method includes acquiring coordinates of defects detected by two or more inspection systems. The defects do not include defects detected on the wafer. The method also includes determining coordinates of the locations on the wafer to be reviewed during the defect review by translating the coordinates of the defects into the coordinates on the wafer such that results of the defect review performed at the locations can be used to determine if the defects cause systematic defects on the wafer.

Determining locations on a wafer to be reviewed during defect review

Computer-implemented methods for detecting defects in reticle design data are provided. One method includes generating a first simulated image illustrating how the reticle design data will be printed on a reticle using a reticle manufacturing process. The method also includes generating second simulated images using the first simulated image. The second simulated images illustrate how the reticle will be printed on a wafer at different values of one or more parameters of a wafer printing process. The method further includes detecting defects in the reticle design data using the second simulated images. Another method includes the generating steps described above in addition to determining a rate of change in a characteristic of the second simulated images as a function of the different values. This method also includes detecting defects in the reticle design data based on the rate of change.

Computer-implemented methods for detecting defects in reticle design data

Disclosed are techniques and apparatus for accounting for differing levels of defect susceptibility in different pattern areas of a reticle in an inspection of such reticle or in inspection of a semiconductor device fabricated from such reticle. In general terms, two or more areas of a reticle are analyzed to quantify each area's susceptibility to defects on the final semiconductor product. That is, each reticle area is analyzed and given a quantified defect susceptibility value, such as a MEEF (mask error enhancement factor) value. Such analysis includes analysis of an image that is estimated to result from the lithography tool which is to be utilized to expose semiconductor devices with the reticle. The defect susceptibility value generally depends on the reticle area's density and whether the correspond area of the estimated lithography image has intensity values which are proximate to an exposure threshold for a particular resist material to be used on the final semiconductor device. The quantified defect susceptibility for each reticle area is then used to selectively set the inspection sensitivity for each reticle area or its corresponding semiconductor device region. The reticle and/or resulting semiconductor device may then be inspected based on the selected sensitivity levels for the different areas of the sample under test.

Apparatus and methods for providing selective defect sensitivity

Disclosed are systems and methods for modifying a reticle. In general, inspection results from a plurality of wafers or prediction results from a lithographic model are used to individually decrease the dose or any other optical property at specific locations of the reticle. In one embodiment, any suitable optical property of the reticle is modified by an optical beam, such as a femto-second laser, at specific locations on the reticle so as to widen the process window for such optical property. Examples of optical properties include dose, phase, illumination angle, and birefringence. Techniques for adjusting optical properties at specific locations on a reticle using an optical beam may be practiced for other purposes besides widening the process window.

Systems and methods for modifying a reticle's optical properties

Disclosed are techniques for determining and correcting reticle variations using a reticle global variation map generated by comparing a set of measured reticle parameters to a set of reference reticle parameters. The measured reticle parameters are obtained by reticle inspection, and the variation map identifies reticle regions and associated levels of correction. In one embodiment, the variation data is communicated to a system which modifies the reticle by embedding scattering centers within the reticle at identified reticle regions, thereby improving the variations. In another embodiment the variation data is transferred to a wafer stepper or scanner which in turn modifies the conditions under which the reticle is used to manufacture wafers, thereby compensating for the variations and producing wafers that are according to design.

Method for determining and correcting reticle variations

Reticles may comprise shading elements (SEs) for locally altering the reticle optical properties. However, such reticles may degrade over time as a result of repeated exposure to radiation in a lithography process, as the radiation may 'heal' the SEs. Disclosed are techniques for monitoring a reticle in order to maintain confidence about the reticle's optical properties and the uniformity of patterns on wafers that are to be printed using the reticle. Reticles undergo periodic inspection comprising reticle transmission measurement and/or aerial imaging of the reticle. When such inspection indicates sufficient reticle degradation, the reticle is tagged for correction prior to its subsequent use in a lithography process.

Method for monitoring a reticle

Disclosed are systems and methods for mitigating variances (e.g., critical dimension variances) on a patterned wafer are provided. In general, variances of a patterned wafer are predicted using one or more reticle fabrication and/or wafer processing models. The predicted variances are used to modify selected transparent portions of the reticle that is to be used to produce the patterned wafer. In a specific implementation, an optical beam, such as a femto-second laser, is applied to the reticle at a plurality of embedded positions, and the optical beam is configured to form specific volumes of altered optical properties within the transparent material of the reticle at the specified positions. These reticle volumes that are created at specific positions of the reticle result in varying amounts of light transmission or dose through the reticle at such specific positions so as to mitigate the identified variances on a wafer that is patterned using the modified reticle.

Systems and methods for mitigating variances on a patterned wafer using a prediction model

Disclosed are methods and apparatus for altering the phase and/or amplitude of an optical beam within an inspection system using one or more spatial light modulator(s) (SLMs). In one embodiment, an apparatus for optically inspecting a sample with an optical beam is disclosed. The apparatus includes a beam generator for directing an incident optical beam onto the sample whereby at least a first portion of the incident optical beam is directed from the sample as an output beam and a detector positioned to receive at least a portion of the output beam. The detector is also operable to generate an output signal based on the output beam. The apparatus further includes one or more imaging optics for directing the output beam to the detector and a programmable spatial light modulator (SLM) positioned within an optical path of the incident or output beam. The SLM is configurable to adjust a phase and/or amplitude profile of the incident beam or the output beam. The apparatus also has a control system operable to configure the SLM to alter the phase and/or amplitude profile of the incident beam or the output beam. For example, the SLM may be configured to alter the illumination profile of the incident beam to achieve different inspection modes. In another example, the SLM may be configured to alter the phase and/or amplitude profile of the output beam so as to substantially eliminate aberrations produced by the imaging optics. In other embodiments, the apparatus may include two or more SLM's which are configurable to alter the phase and/or amplitude profile of both the incident beam and the output beam.

Apparatus and methods for removing optical abberations during an optical inspection

A method and software program for determining printability of a defect on a reticle or photomask onto a substrate during processing. That is performed by creating a pixel grid image having a plurality of individual pixel images showing the defect. A gray scale value is assigned to each pixel image of the pixel grid image and a probable center pixel of the defect is selected. Then the polarity of the defect is determined, with a coarse center pixel of the defect optionally selected using the probable center defect and polarity of the defect. If a coarse center pixel is selected, then a fine center of the defect can optionally be selected from the coarse center pixel and polarity of the defect. From the center pixel the physical extent of the defect can be determined followed by the determination the transmissivity energy level of the physical extent of the defect. Optionally, the proximity of the defect to a pattern edge on the reticle or photomask can be determined using the physical extent and polarity of the defect. Then the printability of the defect can be determined from the transmissivity energy level of the defect and characteristics of the wafer fabrication process being used to produce the substrate from the reticle or photomask.

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San Mateo, CA, United States of America

Zain Saidin