Refer to the Material and Process Compatibility page for information on materials compatible with this tool.
Equipment Status: Set as UP, PROBLEM, or DOWN, and report the issue date (MM/DD) and a brief description. Italicized fields will be filled in by BNC Staff in response to issues. See Problem Reporting Guide for more info.

Status	UP
Issue Date and Description
Estimated Fix Date and Comment
Responding Staff	Harlan, Rich

iLab Name: Woollam M-2000
iLab Kiosk: BRK Metrology Core
FIC: Shared
Owner: Rich Harlan
Location: Cleanroom - L Bay
Maximum Wafer Size: 8-inch wafer

Overview

General Description

The Woollam M-2000 model-X is a spectroscopic ellipsometer used to measure the thickness and index of refractive for transparent and semi-transparent thin films such as oxides, nitrides, resists, polyimides, and polysilicon. The M-2000 measures film characteristics by analyzing the spectral range of 245nm – 1000nm (470 wavelengths) of light that passes through the film or is reflected off the surface.

Specifications

Patented Rotating Compensator Ellipsometer (RCE) design
All 470 wavelengths (245nm - 1000nm) are acquired simultaneously
Typical data acquisition times 1-5 seconds
Collimated light beam with a 5mm diameter
Auto angle base ranging 55° to 75° , horizontal sample stage
Automated stage translation
Automated Tip-Tilt Alignment
Automated sample height (Z) alignment
CompleteEASE software

Sample Requirements and Preparation

The backside of the sample must be free of contaminants that may transfer to the stage. The area of measurement must be void of contaminants for accurate measurements.

Standard Operating Procedure

SAFETY REQUIREMENTS

1.1 Eye protection must be worn whenever in the cleanroom, except when using a microscope or when wearing protective goggles.

1.2 DO NOT BLOCK the movement of the light source or camera base arms.

EQUIPMENT

2.1 Woollam Ellipsometer Model M2000x

o 8-inch Wafer Stage

o Light Source: Xenon arc lamp, 75W output

o Monitor for User Interface

o Stage Motor Controller

o Automatic Tip-Tilt Alignment

TOOL CONFIGURATION

CYCLE OF OPERATION

4.1 Enable the M-2000 in iLab.

4.2 Verify the Xenon lamp is powered on. If not, refer to the startup procedure in Section 6.

4.3 Load the sample in the center of the stage and turn on the vacuum switch.

4.4 Launch the “Complete EASE” application (if not already running) and wait for the system to initialize.

4.5 The System Status display should display “Waiting to Acquire Data” in the measurement tab window. If the System Status is displaying Not Initialized, close and reopen the CompleteEASE application.

4.6 Under “Measurement Controls”, select <Prompt for Acquisition Parameters> next to Recipe.

4.7 Verify the “Save Data after Measurement” is checked (Ö).

4.8 Press the Measure button. The system will require a location to save the data. Right click on the “Researcher Data” folder and select “Create New Sub-Folder” with your last name if you do not have a folder. Otherwise, click on the Researcher Data folder to expand the sub-folders and select your folder.

4.9 Verify your sub-folder is selected and enter a file name before clicking on “Save”.

4.10 Make sure the “High Accuracy Mode” is checked in the “Acquisition Parameter Setup” window. The suggested/typical settings for a silicon substrate are listed below:

4.10.1 Data Type: Standard

4.10.2 Acq Time: 3.00

4.10.3 Angle Scan: 55.00 To 75.00 By 10.00 (if 3-angles are preferred)

4.10.4 Sample Tilt Alignment: Automatic

4.10.5 Sample Height Alignment: Automatic-Quick

4.10.6 Sample Thickness: 0.500 mm

4.10.7 Verify “Align At First Angle” box is checked (Ö).

4.10.8 In the “Other Options” window, verify the “Do Not Reposition Translator” is not checked.

4.10.9 Click the OK button. The M2000 will automatically adjust the Tip, Tilt, and height before measuring the sample.

Adjust the Data Display

4.11 The Psi and Delta graphs will appear when the measurement is complete. Click on the Analysis tab at the top of the display.

Note: If you do not want to view the Delta data (for substrate analysis), click on the “+Data” and uncheck the “Double Y Axis” line. Control P will toggle between Psi and Delta.

Data Analysis of Transparent Films using Sample Model Library

4.12 Click on the Open button under Model.

4.13 Select the Library tab and then click on Basic. If you already have a Model defined, select the ”Projects” tab and then select the model’s name.

4.14 Select the file name that best models your sample such as Si with Thermal Oxide .mod and then click “Open”.

4.15 Verify the values in blue font are correct. To change a value, left click on the value and enter the correct value in the window that has opened. Click “OK” when finished. The value can also be changed by holding the “Shift” key and roll the mouse wheel.

4.15.1 Right click on any value to turn the “fit” on or off.

4.16 Click on “Generate” in the Fit window. At least one value must have the ”fit” turned on before clicking the “Fit” button.

4.17 The dotted black lines in the graph represent the model, the red line is the Psi, and the green line is the Delta. The black dotted line should overlay close to the Psi (and Delta if shown) lines. If not, one or more of the model values are incorrect.

4.18 If a value, such as the thickness, is changed (thicker films will have more interference fringes), click the “Generate” button in the Fit window. NOTE: Zoom in by holding the left mouse button and dragging across the Psi and Delta curves. Double clicking will return to the original line.

4.19 Once the black dotted lines are closely overlayed, click the “Fit” button in the “Fit” window.

4.20 Check the Mean Square Error (MSE) value in the Fit window.

4.21 If the MSE is still too high, click on the “+” next to “OTHER Options” in the Model window. This will expand with more options highlighted in red. Click on “Try Alternate Models” to see the suggested ideal model settings. Use the double arrows to move the selection (green shaded area) over the preferred parameters. Click on the “Apply Chosen Model” button.

4.21.1 The N and K data can be displayed by selecting the “Model” and then select the layer such as Layer1. The specific value can be found by hovering the cursor over the curve at a specific wavelength, such as 632.8nm. Right click in the graph to get the statistics which can be copied to the clipboard.

4.22 Measure a second sample and repeat steps 4.11 through 4.13. The system will use the last model used.

Data Analysis – Manually Build a Model

4.23 Click the “Clear” button in the Model window and then click “Yes”.

4.24 Click on “none” next to Substrate which will open the material library.

4.25 Select the material type, such as Semiconductor for a silicon substrate and then select the substrate type in the right window (Si_JAW.mat) and then click the Open button.

4.26 Click on Add next to the “Layer Commands”, position the cursor in the blue line above “substrate” and left click to open the material library, then select Dielectric for the Oxide layer (SiO2.MAT) and then click the Open button.

4.27 Click on the value next to Thickness #1 and enter the oxide thickness in the window that opens. Click “OK” or press enter when done.

4.28 Right click on the blue thickness value to turn on the “fit” function.

4.29 Click on the Generate button in the Fit window and see if the black dotted lines overlay the Psi and Delta (if displayed) line(s).

4.29.1 You can place the cursor over the Thickness, then hold the shift key and rotate the wheel on the mouse to adjust the thickness to get closer to the measured data. Then click fit. Press the Shift and Ctrl together while rotating the wheel if smaller increments are needed.

4.30 If the overlay is not good, try another .MAT file such as the Cauchy (for dielectrics) in the Basic folder.

4.30.1 Click on the “+” sign next to the Layer #1 to expand the other parameters for this layer.

4.30.2 These parameters can be adjusted for a better fit by right clicking on one of them and then clicking the Fit button or turn off the fit parameter by right clicking on it.

4.30.3 Click on the “+” sign next to the Urbach Absorption to adjust these parameters if necessary.

4.30.4 Make sure the Band Edge value is set to the lowest wavelength used.

4.31 The MSE value should be low.

4.32 Save your data before closing the software, turn off the vacuum and remove your sample.

4.33 Log out of iLab

Scan Pattern Mapping

4.34 Open the Recipe dropdown menu in the Measurement tab.

4.35 Choose the “Create/Edit Recipe” option then click the “Edit/Create” next to “Scan Pattern” or select “<Prompt for Recipe Components>” if a scan recipe already exists.

4.36 The points can be added one at a time or from a

preset list of coordinates. The points can also be copied from another program using the “Paste from Clipboard”. The rest of this procedure uses a reset list of coordinates.

4.37 Select the substrate shape from the

“Substrate Dimensions” dropdown and enter

the dimension.

4.38 Select the type of Point List (Polar Grid) for the

scan and enter the grid values before clicking “OK”.

4.38.1 Radius (mm): 50.00 by 40.00 (for 100mm)

4.38.2 Equidistant Points should be checked.

4.38.3 Spacing (mm): 30.00 (for 9-points)

4.39 When all the Scan Pattern options are completed, save the Scan Pattern for use in a recipe. Select the Model, if available. Click “Close” and press “Measure.”

4.40 After the measurement data is complete, perform the data analysis (description starting at 4.11).

4.41 The data map can be displayed after the “Fit Scan Data” is performed and the thickness layer is selected under “Results”.4.37 Select the substrate shape from the