Download
1 / 75
750 likes | 764 Views
Vector Raptor. Advanced Overlay Analysis & Modeling Model raw data for each structure separately Remove outliers by using the model Use at most a second order polynomial? Use 3 sigma or the range from the population median as a control threshold Agenda Interface Overview
E N D
Vector Raptor Advanced Overlay Analysis & Modeling • Model raw data for each structure separately • Remove outliers by using the model • Use at most a second order polynomial? • Use 3 sigma or the range from the population median as a control threshold • Agenda • Interface Overview • Spatial model generation & graphics • “What-if” scenario • Graph generation using mouse selection • Vector Raptor Excel Workbook Data Storage • Data Storage Organization • Example Reports • Interactive graph customization • Radial Wafer Analysis & Radial Culling • Multi-Pattern Lot Splits (Families) • Results by family • Reports & mouse generated graphics • Model Editor
Concept • Vector Raptor; Classic Overlay Modeling • Employs all classic models for stepper & scanners • WITH additional sophistication in: • Graphics & control • Analysis • Portability • Results reporting • Ability to apply models to whole field, row (reticle scan response) and column (scan-slit response) • Advanced Features • Proprietary modeling engine using adaptive model elements and singular value decomposition • Models adaptive to both singularities and fit-culling • Multi-level, automate and manual methods for data culling • Multi-Family Analysis • For true overlay-structure and pattern-split analysis • Error Source Discrimination • Ability to resolve error sources from between: • Process • Wafer-chuck • Field • Reticle Scan • Lens Slit
Poly DP Solution 193i – 1.2 NA X-Y Polarized light K1 = 0.28 Pitch 90 nm Double Patterning (DP) is a split of the pattern layers to provide sub-0.45 nm lithograph Double Patterning can actually be more than two splits Situations are envisioned of up to five (5) patterned splits that must each undergo multiple alignment, exposure, develop deposition and etch steps.
Double Patterning Concepts • “Double Patterning” • Actually adds multiple alignment and process levels for each split • Mask Critical • Overall mask registration errors will be critical: • Alignment accuracy to scanner registration marks for the layer • Overall mask magnification, uniformity, rotation and skew will become more critical • Processing • Variations in processing can influence not on CD size but the mask response to lens aberrations when wafer is exposed • Greater or less sensitivity to variation in focus, polarization and dose • Process Critical • Alignment sensitivity of the scanner to the registration on the mask • Mask bow/distortion while mask is chucked varies from scanner to scanner • Overlay distortion across a single field is now sensitive to lens-placement distortions from tool response to Dose and deFocus • Problems will exist in trying to understand the sources of these overlay errors due as they vary across the finished device layer.
Vector Raptor Interface • Vector Raptor is an engineering interface • May be used with Weir DM for script automation of any engineering analysis • Data • Data is stored in the TEA Standard metrology format • Microsoft Excel Workbooks are used for data storage • “VR Workbooks” • Any metrology may be imported and stored into VR Workbooks • Reports etc. • All reports, analyses and extractions are stored in the VR data workbook. • Microsoft Windows • XP, 2000, 2004 Server etc.
Vector Raptor Button Bar Import Metrology Data Load Workbook Data Model Editor Print screen Layout Editor Family Member Selection Copy Graphic only View current data in workbook format Active data worksheet in workbook Variable Under Analysis Copy Screen • Model Editor • Create and/or modify substrate and field surface models • Layout Editor • Enter exposure information for each die including focus, dose, NA, Sigma and reticle scan direction • Adjust wafer size, die size, offset, notch etc. • Active Workbook • By default this is the metrology data workbook • Analyses and modeling generate additional data that can also be analyzed and graphed
Loading Data Data Import Drag & drop with mouse • With Vector Raptor • Load RV Workbooks directly • Import any metrology data • Drag & drop any ASCII or workbook into the interface • With Daily Monitor analysis using Vector Raptor models & methods • Load data directly • Drag & drop • Load data, and start analysis, using calls from external programs
“Field Sites” data sheet Data Selection & culling • Exposure Subset Selection for: • Wafer • Focus Dose • Reticle Scan direction • NA • Partial Coherence (Sigma) Data culling by variable range Wafer Layout Field Layout ‘one-click’ histogram for range selection aid
Data Culling & Sub-Set Plotting Mouse-box • Box-in any set of data during selection • With ‘wafer’ you can plot or cull individual data points • With the ‘field’ plot on left, you can remove selected ‘sites’ on the field
Spatial Models • Raw Data analysis of wafer & field • Mouse-sensitive data viewing/graphing Histogram of corner site data Created by boxing in site with mouse
Colored vector-amplitude can be switched off Wafer & Field Modeled results • Apply models as needed • Perform “What-if” scenarios for terms
Note: for this example the field model used here is a simple A +Bx –Cy –DX2 –EY2 And does not represent any valid overlay model. For demo purposes only “What-if” Scenarios • Left – full-field model • Each field individually modeled & results plotted • Right- response with “Piston” or the “offset” removed.
Scale change • Vector-scale, as shown or • Magnitude bar-scale can be changed independently
Graph Generation using mouse Use mouse to graph, delete or spreadsheet-view a section of data Mouse hovered over point to see data value
Graph interface for customization • XY line graphs can also • Create box-plots • Population-density plots • Fit general polynomial trend-lines • Add comments & messages • Rescale with the mouse or by this interface • Etc.
Cull Radius control • Data sets of over 22,000 data sites have been measured
Radial Analysis • Press the “cull radius” command button • Screen appears • Graphic & report generated
Population response for Range & Sigma Cull • Compares multiple “family’s” or pattern-splits • Only one shown here
Multi-Pattern Lot Splits (Families) Lot contains data with three (3) overlay splits Splits are defined in the single data file as different site family values.
Field Model • This summarizes all splits
Results by family Fitted Range of values • Graphs are automatically created
Fitted Reports • Focus and Dose response can also be evaluated
Modeled X & Y overlay split response across wafer • Response across wafer
Model Editor Vector Raptor comes with standard ASML, Nikon and CANON models User customization and model additions are performed using the Model Editor
Covariance • Covariance chart in workbook shown
X-Y Covariance plot • First order fitted line (red) and fit-polynomial message added by graph editor
Wafer model • Wafer offset not included
After data point removal • 14,861 data points • ASML XT1400 XYSMO data
X & Y Overlay • X and Y overlay • Note center-of-wafer “hot” spot
This analysis shows three wafer-based models available for analysis from the library. User can add/delete models Field models can be seen if the user clicks on the field Model Editor • Any number of sequential models • Model coefficients are summarized into one algorithm for each sub-model • Coefficient Control Area • Display name is used in reports • Units-of-measure • Select from drop-down or enter any format such as “nm/cm2” or “ergs/mm2” or ppm etc. • Equation can use any format with variables “X,Y,R and Theta” • Threshold = number of points that must be in the data to use this coefficient • Control bar allows individual coefficient to be created, copied, pasted, deleted or moved up/down in the analysis.
Excluded data points Registration/overlay data excluded by ASML.
