Kla-tencor Technologies Corporation

Kla Tencor Corporation

Sterling G Watson

Zain Saidin

James Norman Wiley

Ady Levy

Stanley E Stokowski

Chris Mack

Ellis Chang

Carl Hess

Sagar A Kekare

William Volk

Sharon McCauley

Paul Frank Marella

Thomas Vavul

Donald J Parker

Anthony Vacca

Yalin Xiong

Larry Steven Zurbrick

Chris A Mack

Zain K Saidin

Methods and systems for inspection of wafers and reticles using designer intent data are provided. One computer-implemented method includes identifying nuisance defects on a wafer based on inspection data produced by inspection of a reticle, which is used to form a pattern on the wafer prior to inspection of the wafer. Another computer-implemented method includes detecting defects on a wafer by analyzing data generated by inspection of the water in combination with data representative of a reticle, which includes designations identifying different types of portions of the reticle. An additional computer-implemented method includes determining a property of a manufacturing process used to process a wafer based on defects that alter a characteristic of a device formed on the wafer. Further computer-implemented methods include altering or simulating one or more characteristics of a design of an integrated circuit based on data generated by inspection of a wafer.

Methods and systems for inspection of wafers and reticles using designer intent data

Methods and systems for inspection of wafers and reticles using designer intent data are provided. One computer-implemented method includes identifying nuisance defects on a wafer based on inspection data produced by inspection of a reticle, which is used to form a pattern on the wafer prior to inspection of the wafer. Another computer-implemented method includes detecting defects on a wafer by analyzing data generated by inspection of the wafer in combination with data representative of a reticle, which includes designations identifying different types of portions of the reticle. An additional computer-implemented method includes determining a property of a manufacturing process used to process a wafer based on defects that alter a characteristic of a device formed on the wafer. Further computer-implemented methods include altering or simulating one or more characteristics of a design of an integrated circuit based on data generated by inspection of a wafer.

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

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.

Growing community of inventors

Palo Alto, CA, United States of America

Sterling G Watson