NANOSPEC 4150 STANDARD OPERATING PROCEDURES

Transcription

1 NANOSPEC 4150 STANDARD OPERATING PROCEDURES Version: 1.0 JAN 2016 UNIVERSITY OF TEXAS AT ARLINGTON Nanotechnology Research Center

2 TABLE OF CONTENTS 1.0 INTRODUCTION HARDWARE OPERATING PROCEDURES LOADING A WAFER FOR TESTING SELECTING A RECIPE USING F3 AUTO MODE RUNNING A RECIPE USING F8 OR F9 MANUAL MODES DATABASE 13 2

3 1.0 Introduction The Model 4150 NanoSpec is an instrument designed to measure the thickness of films deposited on various substrates used in semiconductor and MEMs fabrication. The Model 4150 provides accurate and repeatable measurement s for films ranging from 15nm - 75,000nm in thickness. Two layer films may also be measured on the 4150, but the lower layer thickness must be known. 2.0 Hardware Visible light source Motorized X, Y & Z axis stage System accepts 75mm to 200mm wafer sizes Auto focusing Range of apertures, 5X, 10X, 15X & 50x Custom software to handle measurements and database. 3

4 3.0 Operating Procedures 3.1 Loading a Wafer for Testing Log into the main system computer by entering NANO as the user ID. Then tab down to the Password box and enter The measurement software should now open You will notice two separate wafer loading platforms on the system (Fig. 1). Load the wafer to be measured onto the left side platform. Be careful to get the wafer centered on the platform. There are stops to help center full sized wafers on the stage platform. Fig The right side platform is for a bare silicon reference wafer. A reference is only necessary if it has been longer than 24hrs since the previous reference was performed by the system. Load your bare clean silicon reference wafer onto the right hand platform to run the reference scan. NOTE -This SOP will describe the process of running both the reference scan and measurement scans. If it has been < 24hrs since the prior reference scan was performed then you do not need the reference scan (answer NO when prompted to run it) and you may just skip the following steps which refer to it. 4

5 3.2 Selecting a Recipe using F3 Auto Mode At the top of the computer screen you will see a number of software tabs numbered F1 F10 (Fig. 2). These tabs correspond to your Keyboard F keys. The tabs you ll use to select a recipe will depend on the type of measurement you are going to perform. Tab F3 Auto will run a measurement recipe based on a multi-point preprogrammed map of the wafer. The total measurement points are configurable by staff from 1 to 49 points. The 5 and 9 point tests are the most common on a full sized wafer. Tab F8 User will allow a custom single point test to be run by the user. The recipes in tab F9 STD are single point tests that were set up by the vendor. Pressing the particular F-button will open a second window to allow viewing of the recipe types available for that particular tab. Fig Now press F3 Auto and the system will ask if you want to save the measurements in the database. Answer YES to store the measurements for future access After this another prompt box will open asking for you to enter Parameters. Enter a name or ID that you would like to store the data under. 5

6 3.2.4 Next a recipe selection window will open (Fig. 3). The recipes listed display the recipe #, the # of measurement points, the film type and the substrate. Select the appropriate recipe # from this window and press ENTER. Fig Now the system will prompt as to whether it s been > 24 hours and if you need to run a reference scan. Answer accordingly. If you answer NO then skip ahead to step If you selected YES then the system will tell you to Prepare Substrate for Reference This is your cue to put the clean bare silicon wafer onto the right hand stage if you have not already done so, then press enter. The system will then prompt as to whether or not you would like for the stage to move to the reference position automatically, answer YES. The stage will now move to the center of the right hand platform. Another window will open notifying you that the joystick is active so that you may manually move to a different reference position if required. Once the wafer is properly positioned you are ready to take the reference scan press the OK button and the scan will commence. 6

7 3.2.6 If you selected a two layer measurement recipe in step then a window will now open with a prompt to enter the UNDERLAYER thickness. This is your first layer on the wafer. You must know what this thickness is as the system cannot measure and identify both layers. This step will be skipped if a one layer measurement recipe was selected prior Next the system will ask whether the Cassette/Wafer is ready (Fig. 4). This is referring to the wafer to be measured. If you have not already done so sit your wafer or sample centered onto the left hand platform then press OK. Fig. 4 7

8 3.2.8 The stage will now move to the first measurement point which is programmed into the system. The Joystick Active prompt will come up and you may move the stage manually using the joystick to the correct location if needed. You may also manually focus on the test area if needed by rotating the large dial under the left hand side of the stage (Fig. 5). Once you are sure the measurement point is in view of the camera then select OK. Fig A final box will alert you to Place Wafer, Close UV Shutter, Focus, Etc. Nothing should be needed as this should have all been completed by now. Do not worry about the UV shutter we are not using the UV lamp on this system so the UV shutter will always be closed. Press OK to begin the measurement The system will now begin measuring the first test point. This takes approx. 5 seconds and then the system moves automatically to the next test point The Joystick Active prompt will come on again once the next test point is under the objective. You may move the stage to a better test position if needed. The press OK to begin the next measurement. 8

9 Repeat and continue this process until all of the measurement data points have been collected. Then a final prompt will open asking if you would like to Continue for Another Wafer Y/N. Answer No to this and the screen will now display your individual test point measurements and the Max, Min, Mean, Standard Dev, and Uniformity (Fig. 6) for the test points you just measured. In addition, you may view the Fit curve for the measured data by pressing the F2 Graph button on the screen. This will pull up the fit graph in the lower right hand corner of the screen. Pressing the F2 button again will remove it from the screen. Fig Once you are through you may Press the Alt F6 buttons to once again activate the joystick and manually move the stage to a position which is easy to remove your test sample and the reflectance substrate When you are finished with the System then Press the F5 Logoff button. 9

10 3.3 Running a Recipe using F8 or F9 Manual Modes These two modes are primarily for single point tests or users which are using partial wafers. See step first then proceed to the next step Press F8 for all User configured recipes or F9 for all Standard recipes that were loaded by the vendor. The system will Ask if you would like to store the measurements select Yes After this another prompt box will open asking for you to enter Parameters. Enter a name or ID that you would like to store the data under. It would be best to use your name and a date code. Once you enter this another Parameters box for the wafer will open. Enter a wafer ID if you like Next a Program Selection window will open (Fig. 7). The recipes listed display the recipe #, the # of measurement points, the film type and the substrate. Select the appropriate recipe # from this window and press ENTER. Fig. 7 10

11 3.3.5 You will now be prompted to identify which lens you are using (Fig. 8). Look at the lens turret on the microscope and on the side of the objective in use is printed the magnification of the lens. Typically 5X or 10X lenses are used. Make sure the Selected Lens matches and press Enter. Fig If you selected a two layer measurement recipe in step then a window will now open with a prompt to enter the UNDERLAYER thickness. This is your first layer on the wafer. You must know what this thickness is as the system cannot measure and identify both layers. It will only measure the top layer. This step will be skipped if a one layer measurement recipe was selected prior Now the system will prompt as to whether it s been > 24 hours and if you need to run a reference scan. Answer accordingly. If you answer NO then skip ahead to step If you selected YES then the system will tell you to Prepare Substrate for Reference This is your cue to put the clean bare silicon wafer onto the right hand stage if you have not already done so, then press enter. The system will then prompt as to whether or not you would like for the stage to move to the reference position automatically, answer YES. The stage will now move to the center of the right hand platform. Another window will open notifying you that the joystick is active so that you may manually move to a different reference position if required. Once the wafer is properly positioned you are ready to take the reference scan press the OK button and the reference scan will commence. 11

12 3.3.8 Once you have finished the prior step you will need to Press Alt F6 simultaneously to activate the joystick. Manually move the right stage which contains your sample under the measuring objective. Once the sample is positioned under the objective for measurement press OK Now you may adjust the Focus if necessary of the sample image by manually rotating the stage adjustment (See Fig. 5) You are now ready to measure, Press F10 to perform a single point measurement A final box will alert you to Place Wafer, Close UV Shutter, Focus, Etc. Nothing should be needed as this should have all been completed by now. Do not worry about the UV shutter we are not using the UV lamp on this system so the UV shutter will always be closed. Press OK to begin the measurement. The measurement will take approx. 5 seconds to complete If you wish to perform another single point measurement proceed to Step and move the stage to a new test point using the joystick. Continue as needed using steps 3.3.8, & until all test points have been measured then proceed to the next step Once you are finished with the testing press button F6 Done to display the calculated data for the measured test points (See Fig. 6). A parameters prompt will come on the screen for you to enter or modify the Wafer ID. Enter information if needed then press OK You may now press button F2 to display the Fit Curve graph for your measurement data in the lower right hand corner. Pressing F2 again will turn the graph off If you are finished measuring samples with the system then press the F5 Logoff button. 12

13 4.0 Database To access the stored user database files press the F1 button from the main software screen (See. Fig. 2) This will open a new window (Fig. 9)from which you can pick out a stored data file that you would like to view. Files are listed by date and the ID information which was entered by the user in the Parameters box in steps or Fig Highlight the desired file then click on the Show Measurement Data button on top of the screen. 13

14 4.1.4 A new window will open displaying the data file. Scroll to the right in this window and you will see the thickness measurements. Highlight the column of measurements you wish to view (Fig. 10). Then click on the MAP button at the bottom right of the data file window. Fig A new window will open displaying the map of the wafer and the measured points (Fig. 11). Along with the wafer map will be the other statistics for the measured data. Fig Once you are finished viewing the Wafer Map click on File from the header and then Exit. You will now be at the main Data selection window. To exit this window, once again click on File from the header and select Exit to return to the main system measurement screen. 14