Specific Process Knowledge/Characterization/Stress measurement: Difference between revisions
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=Stress measurement= | =Stress measurement= | ||
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===When a thin film is deposited on one side of the wafer=== | ===When a thin film is deposited on one side of the wafer=== | ||
#Measure the thickness of the wafer | #Measure the thickness of the wafer | ||
#Make a pre-stress measurement. Measure the wafer bow on one of the stylus profilometers in the cleanroom ([[Specific Process Knowledge/Characterization/Profiler#Dektak XTA_new stylus profiler|Dektak | #Make a pre-stress measurement. Measure the wafer bow on one of the stylus profilometers in the cleanroom, the ([[Specific Process Knowledge/Characterization/Profiler#Dektak XTA_new stylus profiler|Dektak XTA]] or [[Specific Process Knowledge/Characterization/Profiler#Stylus Profiler (Tencor P17)|P17 Stylus profiler]]). Save the measurement. It is a good idea to measure across most of the wafer (at least along 70% of the wafer diameter) in two directions perpendicular to each other. Using the P17 profiler you can measure a full radially resolved map of the wafer stress with up to 5° resolution. | ||
#Deposit the thin film | #Deposit the thin film | ||
#Measure the thickness of the thin film (ex. using the FilmTek or the Ellipsometer). | #Measure the thickness of the thin film (ex. using the FilmTek or the Ellipsometer). | ||
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After you make a [[Specific_Process_Knowledge/Characterization/XRD/Process_Info#Theta-2Theta|θ-2θ scan]] of a crystalline thin film, the peak positions can be used to calculate the lattice constant of the film. By comparing the calculated lattice constant to the theoretical one, you can calculate the amount of compressive or tensile stress. It is important to align the thin film carefully to the beam height, as you can in the [[Specific_Process_Knowledge/Characterization/XRD/XRD SmartLab|XRD Smartlab]]. You may use a standard measurement (e.g. of a crystalline Si sample) to be able to take into account the intrinsic peak broadening of the instrument. Use the Ni-filter to remove the K<sub>β</sub> side peaks and if you have enough signal you can also use the monochromator and analyzer crystals to remove the K<sub>α2</sub> contribution. | After you make a [[Specific_Process_Knowledge/Characterization/XRD/Process_Info#Theta-2Theta|θ-2θ scan]] of a crystalline thin film, the peak positions can be used to calculate the lattice constant of the film. By comparing the calculated lattice constant to the theoretical one, you can calculate the amount of compressive or tensile stress. It is important to align the thin film carefully to the beam height, as you can in the [[Specific_Process_Knowledge/Characterization/XRD/XRD SmartLab|XRD Smartlab]]. You may use a standard measurement (e.g. of a crystalline Si sample) to be able to take into account the intrinsic peak broadening of the instrument. Use the Ni-filter to remove the K<sub>β</sub> side peaks and if you have enough signal you can also use the monochromator and analyzer crystals to remove the K<sub>α2</sub> contribution. | ||
Nanolab has the [[Specific_Process_Knowledge/Characterization/XRD/SLSII_analysis|SmartLab Studio software]] and the Malvern Panalytical HighScore software available for quantifying the stress (ask staff for details). There is a good summary of the principles of the strain calculation in the [ | Nanolab has the [[Specific_Process_Knowledge/Characterization/XRD/SLSII_analysis|SmartLab Studio software]] and the Malvern Panalytical HighScore software available for quantifying the stress (ask staff for details). There is a good summary of the principles of the strain calculation in the last section of the [https://labmanager.dtu.dk/view_binary.php?fileId=4247 associated help document] for the SmartLab Studio software. | ||
You may be able to measure the relaxed lattice directly rather than comparing to a theoretical lattice, but you would have to be able to release the film and measure it separately (if this means scraping the thin film off your sample mechanically, you could potentially measure it in the [[Specific_Process_Knowledge/Characterization/XRD/XRD Powder|XRD Powder]], but it would probably be difficult to get enough powder to get a good signal). | You may be able to measure the relaxed lattice directly rather than comparing to a theoretical lattice, but you would have to be able to release the film and measure it separately (if this means scraping the thin film off your sample mechanically, you could potentially measure it in the [[Specific_Process_Knowledge/Characterization/XRD/XRD Powder|XRD Powder]], but it would probably be difficult to get enough powder to get a good signal). | ||