1 Rudolph Ellipsometer Standard Operating Procedure Equipment Name: Rudolph Ellipsometer Model: AutoEL IV NIR3 Light source: Tungsten Halogen Incandescent Operating Wavelength: 633nm, 830nm, 405 nm Location: 1419 - Metrology Version: 3.0 Date: March 15, 2011 Description: Ellipsometry is a non-destructive method of measuring the index of refraction and film thickness of a dielectric film on a reflecting substrate. It is a highly accurate and repeatable measurement. Ellipsometry involves illuminating the surface of a sample with monochromatic light having a known and controllable state of polarization and analyzing the polarization state of the reflected light. Operating Instructions: Sign on: fill in the log sheet with your name and login time. Instrument Warming up 1. Switch on the Video Monitor (Ikegami PM9-5). 2. Switch on the Panasonic Camera Drive Unit WV-P5 11A. 3. Switch on the Ellipsometer (the switch is on the lower left side of the instrument) and wait for 15 minutes for it to warm up. 4. Switch on the ACT lamp (the switch is at the upper right corner of the instrument face). Instrument Initialization 5. Press the RESET key, watch the unit screen display going through the following sequences: 1) “Moving compensator to home position”. 2) “Moving filter to home position” 3) “Moving compensator to home position 2”. 4) “Establish SECS-II Communication”. 5) “Insert Sample – press CONTinue”. 6. Place the reference sample in the middle of the sample stage. 1) For fine positioning, adjust the X-Y micrometers located to the left and also the front of the stage. 2) For gross positioning, move the wafer to a new location on the stage. 7. Press the “CONT” button 8. The unit screen displays “Align Sample – press CONTinue” Sample alignment refers to adjusting the height and tilt of the sample stage such that the surface of the sample positioned on the stage is aligned correctly with respect to the polarizer and analyzer modules. (For detail instruction, please refer to Apendix IV) 1) Tilt adjustment: push the ACT block to the back position (away from you), look for bright spot (circle) on the video monitor, if the sample tilt is not too far off, a spot of white light will appear somewhere in the field of view. The white spot should be centered on both
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Rudolph Ellipsometer Standard Operating Procedure Equipment Name: Rudolph Ellipsometer Model: AutoEL IV NIR3 Light source: Tungsten Halogen Incandescent Operating Wavelength: 633nm, 830nm, 405 nm Location: 1419 - Metrology Version: 3.0 Date: March 15, 2011 Description: Ellipsometry is a non-destructive method of measuring the index of refraction and film thickness of a dielectric film on a reflecting substrate. It is a highly accurate and repeatable measurement. Ellipsometry involves illuminating the surface of a sample with monochromatic light having a known and controllable state of polarization and analyzing the polarization state of the reflected light. Operating Instructions: Sign on: fill in the log sheet with your name and login time. Instrument Warming up
1. Switch on the Video Monitor (Ikegami PM9-5). 2. Switch on the Panasonic Camera Drive Unit WV-P5 11A. 3. Switch on the Ellipsometer (the switch is on the lower left side of the instrument) and wait for 15
minutes for it to warm up. 4. Switch on the ACT lamp (the switch is at the upper right corner of the instrument face).
Instrument Initialization 5. Press the RESET key, watch the unit screen display going through the following sequences:
1) “Moving compensator to home position”. 2) “Moving filter to home position” 3) “Moving compensator to home position 2”. 4) “Establish SECS-II Communication”. 5) “Insert Sample – press CONTinue”.
6. Place the reference sample in the middle of the sample stage. 1) For fine positioning, adjust the X-Y micrometers located to the left and also the front of the
stage. 2) For gross positioning, move the wafer to a new location on the stage.
7. Press the “CONT” button 8. The unit screen displays “Align Sample – press CONTinue”
Sample alignment refers to adjusting the height and tilt of the sample stage such that the surface of the sample positioned on the stage is aligned correctly with respect to the polarizer and analyzer modules. (For detail instruction, please refer to Apendix IV)
1) Tilt adjustment: push the ACT block to the back position (away from you), look for bright spot (circle) on the video monitor, if the sample tilt is not too far off, a spot of white light will appear somewhere in the field of view. The white spot should be centered on both
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vertical and horizontal crosshair. If it is not, you need to adjust the three knobs under the stage.
2) Height adjustment: pull the ACT block all the way out (towards you), view sample on the video monitor, rotate height adjustment H to raise or lower the sample until the sample features or the white spot appear in sharp focus.
3) Readjust sample tilt if needed. 9. Press “CONT” button. 10. The unit screen displays “Version Control 601EB.34.17”. 11. The unit screen displays “Press RUN, LEARN, or CONT”.
Sample Measurement 12. Put the reference sample away. 13. Place your sample in the middle of the sample stage. 14. Do sample alignment by following 8. 1)-3). 15. To make a measurement, you can either run an existing program, or make your own program.
First take a look at Appendix I to see if there is already a program for your application. If yes, go to step 16. If not, press “Learn” button, and follow the instructions in Appendix II.
16. Press “RUN”. 17. The unit screen displays “RUN Program: ” 18. Input the program file number you wish to run (either a file number you found in Appendix I, or a
file number you just programmed in step 15), and press “enter” button. 19. The instrument may ask for an estimated value of a parameter, for example, the following prompt
could appear on the display: “Spec. Thickness: [1000]? ”, you can type in your estimated film thickness and then press “Enter” button, or simple press the “Enter” button to accept the default value “1000 Angstroms”.
20. The instrument will start measurement and output the result to the PC screen. Please make sure the Ellipsometry applet is running on the PC.
21. After finish your measurement, shut down the system by reversing the steps 1-4. 22. Sign off: fill in the log sheet with logout time, substrate and films measured and comments.
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Appendix I Pre-Programmed files and applications:
File # Calculating
Routine Measuring
Routine Lambda(Å) Calculate Application Deferred
Parameters 20 10 2 6328 TU, NU STSi -- 21 11 2 6328 TU STSi NU 22 12 2 8300 TU, NU STSi -- 23 13 2 8300 TU STSi NU 24 12 2 4050 TU, NU STSi -- 25 13 2 4050 TU STSi NU 26 49 2 6328 TU, NU, KU PTSi NL, TL 27 49 3 8300 TU, NU, KU PTSi NL, TL 28 70 2 -- NS, KS OCBS LAMBDA 29 0 2 -- NS, KS DP LAMBDA Code Application ------ ----------------------------------- STSi: Single, transparent films on silicon substrates. Note: When this application uses calculating routine 10, the initial iteration NU guess
value is fixed at NUg=1.7, which limits the application to films with NU reasonably close to 1.7, such as oxides and nitrides.
PTSi: Polysilicon over a single, transparent film on silicon. OCBS: Optical constants of bare substrate DP: DELTA and PSI measurement only, any surface, no calculations. TU: Upper-layer film thickness NU: Upper-layer film refractive index KU: Upper-layer film extinction index TL: Lower-layer film thickness NL: Lower -layer film refractive index KL: Lower -layer film extinction index NS: Substrate refractive index KS: Substrate extinction index LAMBDA: Wavelength of light used for measurement
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Appendix II Program and run customized Files Files 00-09 are for general use.
1. Press “LEARN” button 2. Program File Number: enter 00-09 3. Measuring Routine Number: 2 4. Calculating Routine Number: choose from the table below 5. Printer Format Number: 5 6. Serial Output Format: 0 7. Enter Ident. Option: 0 8. Spec. Thickness: [1000]? Press “DEFER” button
After finishing programming, run the file you just programmed.
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Chart of Calculating Routines
Application Calculating
Routine
Experimental Configuration
Film Layer Characterisitcs (TU always CALC)
Substrate Characteristics
LAMBA (A)
PHI (deg)
NU KU NL KL TL (A)
NS KS
Transparent, Single films
10 6328 70.00 CALC 0.0 - - - 3.858 0.018 (Si) 11 6328 70.00 E 0.0 - - - 3.858 0.018 12 E E CALC 0.0 - - - E E 13 E E E 0.0 - - - E E
Transparent, Double films
21 6328 70.00 E 0.0 E 0.0 E 3.858 0.018 (Si) 22 6328 70.00 CALC 0.0 E 0.0 E 3.858 0.018 (Si) 23 6328 70.00 E 0.0 CACL 0.0 E 3.858 0.018 (Si) 24 E E CALC 0.0 E 0.0 E E E 25 E E E 0.0 CACL 0.0 E E E 26 E E E 0.0 E 0.0 E E E 27 6328 70.00 E 0.0 E 0.0 CACL 3.858 0.018 (Si) 28 E E E 0.0 E 0.0 CACL E E
Absorbing, Single films
31 E E CALC E - - - E E 32 E E E CACL - - - E E 33 E E E E - - - E E
Absorbing, Double films
41 E E CALC E E E E E E 42 E E E CACL E E E E E 43 E E E E CACL E E E E 44 E E E E E CACL E E E 45 E E E E E E CACL E E 46 E E E E E E E E E
Polysilicon over single film on substrate
48 5461 70.00 CALC CACL E E E E E 49 6328 70.00 CALC CACL E E E 3.858 0.018 (Si)
49 E E CALC CACL E E E E E
Optical constants of bare substrate 70 E E - - - - - CACL CACL
LEGEND: (A): Angstroms NL: Lower-layer film refractive index (Si): Silicon KL: Lower-layer film extinction index CACL: Calculated quantity TL: Lower-layer film thickness E: Enter known value NS: Substrate refractive index -: Not applicable KS: Substrate extinction index
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Appendix III Relative Accuracy Test: Rudolph Check Sample A9291-1100 File # 24 20 23 Wavelength (Å) 4050 6328 8300 Calculate NU yes yes no Enter NU 1.470g 1.460g 1.455 TU (Å) within 10 10 10 NU within 0.010 0.010 -- “g” denotes an initial iteration guess value. Appendix IV Tilt and height adjustment Please see next page.
