Various methods and systems for utilizing design data in combination with inspection data are provided. One computer-implemented method for binning defects detected on a wafer includes comparing portions of design data proximate positions of the defects in design data space. The method also includes determining if the design data in the portions is at least similar based on results of the comparing step. In addition, the method includes binning the defects in groups such that the portions of the design data proximate the positions of the defects in each of the groups are at least similar. The method further includes storing results of the binning step in a storage medium.

Methods and systems for utilizing design data in combination with inspection data

Various methods and systems for determining a position of inspection data in design data space are provided. One computer-implemented method includes determining a centroid of an alignment target formed on a wafer using an image of the alignment target acquired by imaging the wafer. The method also includes aligning the centroid to a centroid of a geometrical shape describing the alignment target. In addition, the method includes assigning a design data space position of the centroid of the alignment target as a position of the centroid of the geometrical shape in the design data space. The method further includes determining a position of inspection data acquired for the wafer in the design data space based on the design data space position of the centroid of the alignment target.

Methods and systems for determining a position of inspection data in design data space

Computer-implemented methods and systems for detecting defects in a reticle design pattern are provided. One computer-implemented method includes acquiring images of the reticle design pattern using a sensor disposed on a substrate arranged proximate to an image plane of an exposure system configured to perform a wafer printing process using the reticle design pattern. The images illustrate how the reticle design pattern will be projected on a wafer by the exposure system at different values of one or more parameters of the wafer printing process. The method also includes detecting defects in the reticle design pattern based on a comparison of two or more of the images corresponding to two or more of the different values.

Methods and systems for detecting defects in a reticle design pattern

Various computer-implemented methods are provided. One method for evaluating reticle layout data includes generating a simulated image using the reticle layout data as input to a model of a reticle manufacturing process. The simulated image illustrates how features of the reticle layout data will be formed on a reticle by the reticle manufacturing process. The method also includes determining manufacturability of the reticle layout data using the simulated image. The manufacturability is a measure of how accurately the features will be formed on the reticle. Also provided are various carrier media that include program instructions executable on a computer system for performing a method for evaluating reticle layout data as described herein. In addition, systems configured to evaluate reticle layout data are provided. The systems include a computer system and a carrier medium that includes program instructions executable on the computer system for performing method(s) described herein.

Methods, systems, and carrier media for evaluating reticle layout data

Systems and methods for creating inspection recipes are provided. One computer-implemented method for creating an inspection recipe includes acquiring a first design and one or more characteristics of output of an inspection system for a wafer on which the first design is printed using a manufacturing process. The method also includes creating an inspection recipe for a second design using the first design and the one or more characteristics of the output acquired for the wafer on which the first design is printed. The first and second designs are different. The inspection recipe will be used for inspecting wafers after the second design is printed on the wafers using the manufacturing process.

Systems and methods for creating inspection recipes

For alternating aperture phase shift masks (AAPSM) and 193 nm (ArF) lithography, we have simulated defect printability using inspection images and software-based modeling. Masks were fabricated by DuPont Photomasks with programmed defects of known size, phase, and location. Three phase layers were used to generate defect angles 60, 120 and 180 degrees. Simulated wafer prints were performed using Numerical Technologies’ Virtual Stepper System, which takes inspection images as input and models the lithographic process. With inspection images from KLA-Tencor’s SLF27 system, our critical-dimension measurements show good agreement with those from wafers printed on an ASML PAS 5500/900 scanner.

Simulation-based Defect Printability Analysis on Alternating Phase Shifting Masks for 193nm Lithography

Simulated wafer images for Attenuated Phase Shift Mask (ATTPSM) features are performed by the Virtual Stepper System. The ATTPSM test reticles were prepared with programmed defects (hard defects and phase defects) on line/space patterns, contact hole patterns, and rectangle patterns for 150-nm design rules. Each defect area was inspected using KLA-Tencor's UV-HR365 and SLF27 inspection systems. Virtual Stepper simulations are compared with Aerial Image Measurement System (AIMSTM) simulation at best focus and at multiple defocus levels. In addition, simulation accuracy from different inspection images is compared.

Simulation based defect printability analysis on Attenuated Phase shifting masks

As 90 nm devices enter into the pre-production phase, the quality assurance strategy of photomasks for those devices must be well established with the proper cost and turn-around-time in mind. Such devices will be manufactured with a state-of-the-art photolithography systems equipped with 193nm actinic light sources. Photomasks for these devices are being produced with the most advanced equipment, material and processing technologies and yet, quality assurance still remains an issue for volume production. These issues include defect classification and disposition due to the insufficient resolution of the defect inspection system, uncertainty of the impact the defects have on the printed feature as well as inconsistencies of classical defect specifications as applied in the sub-wavelength era. To overcome these issues, the authors propose a new strategy to assess photomask quality by checking the CD variation on wafer (defect printability) using aerial image simulation. This method of simulation-based mask qualification uses aerial image defect simulation in combination with a high resolution optical review system with shorter review wavelength (248nm) and smaller pixel size (22.5nm)- combining the defect inspection system with a longer inspection wavelength (365nm) and larger pixel size (150nm). This paper discusses a new strategy on mask quality assurance with several experimental results that proves the applicability for enabling 90nm technology nodes. Combining high-resolution optical images captured by DUV measurement tool with Virtual Stepper System has achieved better accuracy for 0.72um contact holes on ArF Att.PSM. However, we need further investigation for precise prediction of CD variation caused by defects on 0.4um line/space patterns on ArF Att.PSM. This paper also discusses future work to make the strategy production-worthy.

Photomask quality assessment strategy at 90-nm technology node with aerial image simulation

In this paper, we demonstrate new simulation capabilities for defect dispositioning of alternating aperture phase shift masks (AAPSM). A defect mask for use in a 248 nm exposure tool was fabricated with programmed phase defects. Inspection images of the defects were taken on Lasertec's MD3000 and KLA-Tencor's SLF27 inspection systems. The simulation tool takes defect images as input and simulates photolithography performance via aerial image modeling. We present preliminary modeling results that show good agreement between simulated CDs and the CDs from Aerial Image Measurement System (AIMSTM) measurements. This work shows the potential for extending Virtual Stepper?System to AAPSMs on a variety of inspection platforms.

Defect printability analysis on alternating phase-shifting masks

For alternating aperture phase shift masks (AAPSM), phase-defect detection and disposition is more difficult for 193 nm (ArF) lithography than for 248 nm (KrF) lithography, as pattern geometry is tighter and quartz etching is shallower. For ArF lithography, we designed and fabricated a new test mask to confirm detectability and printability of phase defects, extending our previous work for KrF lithography. This test mask has precise defect sizes and phase-error angles of 25, 50, and 75 degrees. Detectability was demonstrated on KLA-Tencor’s SLF27 and investigated by acquiring defect images on SLF27 and LaserTec’s MD3000 inspection systems. Printability was compared between actual wafer prints, and simulations from Carl Zeiss’ Aerial Image Measurement System (AIMS). Wafer prints were also simulated using Numerical Technologies’ software-based Virtual Stepper System, which takes inspection images as input and models the optical aspects of lithography. Virtual Stepper critical-dimension measurements show good general agreement with those from AIMS images and wafer-print SEM images. Compared to AIMS, which is a hardware-based simulator that uses the actual mask as input, the software-based Virtual Stepper System is easier to adapt to different processes and to integrate into the production flow.

Linyong Pang

Papers

Simulation-based Defect Printability Analysis on Alternating Phase Shifting Masks for 193nm Lithography

Simulation based defect printability analysis on Attenuated Phase shifting masks

Photomask quality assessment strategy at 90-nm technology node with aerial image simulation

Defect printability analysis on alternating phase-shifting masks

Study of Defect Printability Analysis on Alternating Phase Shifting Masks for 193 nm Lithography