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Topographic measurements are measurements were you can measure hight differences on your substrate. If you measure in many spots of you substrate you can get a topographic image of your substrate.
{{cc-nanolab}}


AT DANCHIP we have three systems for topographic measurement:
'''Feedback to this page''': '''[mailto:Characterization@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Characterization/Topographic_measurement click here]'''  
*Tencor - ''Profiler for measuring micro structures''
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*Dektak - ''Profiler for measuring micro structures''
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*Nanoman - ''AFM for measuring nano structures''
=Topographic measurements=
Topographic measurements are measurements of height differences on your sample. If you measure many spots on the sample you can get a topographic image of the surface.


'''High Aspect ratio structures'''<br/>
At DTU Nanolab we have eight systems for topographic measurements:
The fact that the tips of the profilers and the AFM are shaped like a cone with some tip angle causes a problem when characterizing high aspect ratio structures. For instance, if a 20 <math>\mu</math>m wide trench is etched deeper than approximately 18 <math>\mu</math>m, the tip of the Dektak will not be able to reach the bottom. In this case the only solution is to cleave the sample along a line that is perpendicular to the trench and then put it in a [[Specific Process Knowledge/Characterization/SEM: Scanning Electron Microscopy|scanning electron microscope]].
*Stylus profilers (P17, Dektak XTA, Dektak 150 and Dektak 3ST) - ''Profilers for mechanically measuring topography''  
*Optical profilers (Optical profiler Sensofar and Optical profiler Filmetrics) - ''3D Profilers for optically measuring topography''
*AFMs (AFM Icon-PT1 and AFM Icon-PT2) - ''AFMs for "mechanically" measuring topography (nano-regime)''
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==High Aspect Ratio Structures==
The fact that the stylus tip of a stylus profiler or an AFM is shaped like a cone with some finite tip angle causes a problem when characterizing high aspect ratio structures. For instance, if a 20 µm wide trench is etched deeper than approximately 18 µm, the tip of the Dektak will not be able to reach the bottom. The optical profiler uses a light beam that is focused through an objective. Therefore it is able to measure higher aspect ratios. The aspect ratio is limited by the possibility for the light to reach the bottom and get back to the detector. On some samples we have been able to measure aspect ratios above 1:10. Otherwise the solution is to cleave the sample along a line that is perpendicular to the trench and then inspect the profile in a [[Specific Process Knowledge/Characterization/SEM: Scanning Electron Microscopy|scanning electron microscope]] or a microscope (for large structures).
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==Thin Film Thickness==
The profilers can be used to measure the thickness of optically transparent thin films or etched non-transparent thin films. There are also other options for measuring film thickness. All the methods are compared on the [[Specific Process Knowledge/Characterization/Measurement of film thickness and optical constants| "Measurement of Thin Film Thickness and Optical Constants"]] page.
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===Comparison of the two profilers and the AFM===
=Comparison of Stylus Profilers, Optical Profilers and AFMs at Nanolab=
{| border="2" cellspacing="0" cellpadding="4" align="center"
 
!.
{|border="1" cellspacing="1" cellpadding="3" style="text-align:left;"
!Tencor
|-
!Dektak
 
!Nanoman
|-
|- valign="top"
|-style="background:silver; color:black"
|'''General description'''
!
|Profiler for measuring micro structures
![[Specific Process Knowledge/Characterization/Tencor P17|Tencor P17 <br>(Stylus Profiler)]]
|Profiler for measuring micro structures. Can do wafer mapping and stress measurements.
![[Specific Process Knowledge/Characterization/Dektak_XTA|Dektak XTA <br>(Stylus Profiler)]]
![[Specific_Process_Knowledge/Characterization/Dektak_150|Dektak 150 <br>(Stylus Profiler)]]
![[Specific Process Knowledge/Characterization/Dektak_3ST | Dektak_3ST <br>(Stylus Profiler)]]
![[Specific_Process_Knowledge/Characterization/Sensofar_S_Neox|Sensofar S Neox <br>(Optical Profiler)]]
![[Specific Process Knowledge/Characterization/Filmetrics|Filmetrics <br>(Optical Profiler)]]
![[Specific Process Knowledge/Characterization/AFM: Atomic Force Microscopy|AFM Icon 1 and AFM Icon 2 <br>(Atomic Force Microscopy)]]
|-
 
|-
|-style="background:WhiteSmoke; color:black"
!Generel description
|Profiler for measuring microstructures in cleanroom. Excellent stress measurements. Excellent sequence programs. Plus wafer mapping and roughness measurements.
|Profiler for measuring microstructures in cleanroom. Quick and easy vertical profiling. Plus wafer mapping, roughness and stress measurements.
|Profiler for measuring microstructures in building 347.
|Profiler for measuring microstructures in building 346 basement.
|3D Profiler for measuring microstructures and surface roughness. Can do wafer mapping. In cleanroom
|3D Profiler for measuring microstructures and surface roughness. Can do wafer mapping. In basement below cleanroom.
|AFM for measuring nanostructures and surface roughness
|AFM for measuring nanostructures and surface roughness
|-valign="top"
|-
|'''Substrate size'''
 
|small pieces -> 4"
|-
|2" -> 8"
|-style="background:LightGrey; color:black"
|6" or less
!Max. Scan Range xy
|-valign="top"
|Line scan x: 1 µm to 200mm.
|'''Max. scan range xy'''
Map scan xy: up to the largest square that can be inscribed in an 8" wafer
|Line scan x: Full substrate size
|Line scan x: 50 µm to 55 mm in one scan. Maximum scan length with stitching 200mm.
|Line scan x: 50µm to 200mm
|Line scan x: 50 µm to 55 mm
|Line scan x: 50 µm to 55 mm
|Depending on the objective:
*One view: 127µmX95µm to 1270µmX955µm
*Stitching: In principle a whole 6" wafer (time consuming)
|Only 10x objective: 2.0 mm x 1.7 mm
|90 µm square
|90 µm square
|-valign="top"
|-
|'''Max. scan range z'''
 
|<100Å to~0.3mm
|-
|50Å to 262µm
|-style="background:WhiteSmoke; color:black"
!Max. Scan Range z
|up to 900 µm
|50 Å to 1 mm
|50 Å to 1 mm
|100 Å to 130 nm
|Depending on the objective and Z resolution:
*94.4 µm ->9984 µm
|10 mm (piezo range 500 µm)
|1 µm (can go up to 5 µm under special settings)
|1 µm (can go up to 5 µm under special settings)
|-valign="top"
 
|'''Resolution xy'''
|-
|up to 5900 data points per profile
|-style="background:LightGrey; color:black"
|down to 0.067 µm
!Resolution xy
|down to 0.025 µm
|down to 0.003 µm
|down to 0.003 µm
|down to 0.5 µm
|Depending on the objective:
*0.5µm -> 5µm
|Resolving power of the lens: 0.92 µm
|Depending on scan size and number of samples per line and number of lines - accuracy better than 2%
|Depending on scan size and number of samples per line and number of lines - accuracy better than 2%
|-valign="top"
|-
|'''Resolution z'''
 
|or 25Å
|-
|, 10Å or 20Å
|-style="background:WhiteSmoke; color:black"
!Resolution z
|0.01, 0.08 or 0.6 Å depending on range (note resolution below 1 Å is below the noise level)
|1 Å, 10 Å, 40 Å or 160 Å depending on range
|1 Å, 10 Å or 20 Å depending on range
|1 Å, 10 Å, 40 Å or 160 Å depending on range
|Depending on measuring methode:
*PSI down to 0.01 nm
*VSI down to 1 nm
*Confocal (depending on objective): 1nm -> 50nm
|
*Accuracy 0.7%
*Precision 0.1%
|<1Å - accuracy better than 2%
|<1Å - accuracy better than 2%
|- valign="top"
 
|'''Max. scan depth [µm] (as a function of trench width W''')
|-
|0.87(W[µm]-5µm)
|-style="background:LightGrey; color:black"
|1.2(W[µm]-5µm)
!Max. Scan Depth [µm] (as a function of trench width W)
|~1 with standard cantilever.
|0.866*(W[µm]-2µm)
|-valign="top"
|1.2*(W[µm]-5µm)
|'''Tip radius'''
|1.2*(W[µm]-5µm)
|5 µm 60<sup>o</sup> cone
|1.2*(W[µm]-2.5µm)
|Depending on material and trench width:
*Somewhere between 1:1 and 1:12
|Depending on material and trench width.
|~1:1 with standard cantilever.
 
|-
 
|-
|-style="background:WhiteSmoke; color:black"
!Standard Tip Radius
|2 µm 60<sup>o</sup> cone
|5 µm 45<sup>o</sup> cone
|5 µm 45<sup>o</sup> cone
|5 µm 45<sup>o</sup> cone
|2.5 µm 45<sup>o</sup> cone
|No tip - using light
*Blue monochromatic LED: 460nm
*White broadband LED: 550nm
|No tip - using light
*Blue monochromatic LED: 460nm
*White broadband LED: 550nm
|<12 nm on standard cantilever
|<12 nm on standard cantilever
|-valign="top"
|-
|'''Stress measurement'''
 
|Can be done
|-style="background:LightGrey; color:black"
!Stress Measurement
|Excellent capability
|Can be done
|Can be done
|
|
|No stress calculation capability
|Cannot be done
|Cannot be done
|Cannot be done
|-valign="top"
|
|'''Surface roughness'''
 
|-
|-style="background:WhiteSmoke; color:black"
!Surface Roughness
|Can be done on a line or map (parallel line scans)
|Can be done on a line scan
|Can be done on a line scan
|Can be done on a line scan
|Can be done on a line scan
|Recommend P17 or Dektak XTA
|Can be done on a line or an area
|Can be done on a line or an area
|Can be done on a selected surface area  
|Can be done on a selected surface area  
|-  
|-
 
|-
|-style="background:LightGrey; color:black"
!Substrate Size
|up to 8"
|up to 6"
|up to 6"
|up to 4"
|Up to more than 6"
|100x100 mm
|6" or less
|-
 
|-
|-style="background:WhiteSmoke; color:black"
!Allowed Materials
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|
Almost any material that leaves no residuals; please ask responsible group about non-standard materials.
|-
 
|-
|-style="background:LightGrey; color:black"
!Location
|Cleanroom F-2
|Cleanroom B-1
|Building 347, SupportLab
|Basement, building 346, room 904
|Cleanroom C-1
|Basement, building 346, room 904
|AFM Icon1: Cleanroom C-1
AFM Icon2: Basement, building 346, room 904
|-
 
|}
|}