View source for Specific Process Knowledge/Characterization/SEM: Scanning Electron Microscopy


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=Scanning Electron Microscopy at Nanolab=
There is a large range of scanning electron microscopes (SEMs) at DTU Nanolab. The first couple of sections on this page are about the SEMs in and around the fabrication part of Nanolab in building 346 and 451. The last section is about the SEMs in building 314, which is our dedicated characterization facility.

== Scanning electron microscopy in and around the cleanroom==
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The four SEMs in building 346 and 451 cover a wide range of needs both in the cleanroom and outside: From fast in-process verification of different process parameters such as etch rates, step coverages or lift-off quality to ultra high resolution images on any type of sample intended for publication. 

* The [[Specific_Process_Knowledge/Characterization/SEM_Supra_1|SEM Supra 1]] is located in the basement outside the cleanroom. It is serving two purposes: Serving the users that have samples from outside the cleanroom and serving as training tool; all new SEM users with no/little SEM experience must be trained on this tool and gain basic knowledge (typically 10 hours of usage) here before being qualified for training on the SEMs in the cleanroom.

* The [[Specific_Process_Knowledge/Characterization/SEM_Supra_2|SEM Supra 2]] and [[Specific_Process_Knowledge/Characterization/SEM_Supra_3|SEM Supra 3]] are located in the cleanroom where they serve as general imaging tools for samples that have been fabricated in the cleanroom. Like SEM Supra 1, they are VP models from Carl Zeiss and will produce excellent images on any sample. The possibility of operating at higher chamber pressures in the VP mode makes imaging of bulk non-conducting samples possible. The [[Specific_Process_Knowledge/Characterization/SEM_Supra_2|SEM Supra 2]] is also equipped with an airlock and an EDX detector.

* The [[Specific_Process_Knowledge/Characterization/SEM_Gemini_1|SEM Gemini 1]] is is a new SEM fra Carl Zeiss that is being installed in the cleanroom at the moment (August 2023)

* The [[Specific_Process_Knowledge/Characterization/SEM_Tabletop_1|SEM Tabletop 1]] is a tabletop SEM that is located in the basement outside the cleanroom. It has a limited resolution, but it is fast and easy to use, also for non-conducting samples. Training in the others SEMs is not required to use this SEM.

SEM Supra 1, 2 and 3 and the SEM Gemini 1 are all manufactured by Carl Zeiss. The SEM Supra 1, 2 and 3 all have the same graphical user interface and nearly identical electron optics. But there are there are small hardware and software differences, thus a training is needed for each SEM you want to use.

The SEM Tabletop 1 is manufactured by Hitachi.

== Common challenges in scanning electron microscopy ==

*[[/samplemount| Sample mounting]]

==Comparison of SEM's in building 346/451==

{| border="2" cellspacing="0" cellpadding="0" 
!colspan="2" border="none" style="background:silver; color:black;" align="center"|Equipment 
|style="background:WhiteSmoke; color:black" align="center"|[[Specific_Process_Knowledge/Characterization/SEM_Supra_1|SEM Supra 1]]
|style="background:WhiteSmoke; color:black" align="center"|[[Specific_Process_Knowledge/Characterization/SEM_Supra_2|SEM Supra 2]]
|style="background:WhiteSmoke; color:black" align="center"|[[Specific_Process_Knowledge/Characterization/SEM_Supra_3|SEM Supra 3]]
|style="background:WhiteSmoke; color:black" align="center"|[[Specific_Process_Knowledge/Characterization/SEM_Gemini_1|SEM Gemini 1]]
<i>Under installation</i>
|style="background:WhiteSmoke; color:black" align="center"|[[Specific_Process_Knowledge/Characterization/SEM_Tabletop_1|SEM Tabletop 1]]
<!--|style="background:WhiteSmoke; color:black" align="center"|[[Specific Process Knowledge/Characterization/SEM FEI QUANTA 200 3D|FEI Quanta 200 3D]]
|-
!colspan="2" border="none" style="background:silver; color:black;" align="center"|Model 
|style="background:WhiteSmoke; color:black" align="center"| Zeiss Supra 40 VP
|style="background:WhiteSmoke; color:black" align="center"| Zeiss Supra 60 VP
|style="background:WhiteSmoke; color:black" align="center"| Zeiss Supra 40 VP
|style="background:WhiteSmoke; color:black" align="center"| Zeiss GeminiSEM 560
|style="background:WhiteSmoke; color:black" align="center"| SEM Tabletop 1
<!--|style="background:WhiteSmoke; color:black" align="center"| FEI Quanta 200 3D-->
|-
!style="background:silver; color:black" align="center" valign="center" rowspan="2"|Purpose 
|style="background:LightGrey; color:black" align="center" | Imaging and measurement of
|style="background:WhiteSmoke; color:black"|
* Conducting samples
* Semi-conducting samples
* Thin (~ 5 µm <) layers of non-conducting materials such as polymers
* Thick polymers, glass or quartz samples
|style="background:WhiteSmoke; color:black"|
* Conducting samples
* Semi-conducting samples
* Thin (~ 5 µm <) layers of non-conducting materials such as polymers
* Thick polymers, glass or quartz samples
|style="background:WhiteSmoke; color:black"|
* Conducting samples
* Semi-conducting samples
* Thin (~ 5 µm <) layers of non-conducting materials such as polymers
* Thick polymers, glass or quartz samples
|style="background:WhiteSmoke; color:black"|
* Conducting samples
* Semi-conducting samples
* Thin (~ 5 µm <) layers of non-conducting materials such as polymers
* Thick polymers, glass or quartz samples
|style="background:WhiteSmoke; color:black"|
* Conducting samples
* Semi-conducting samples
* Thin (~ 5 µm <) layers of non-conducting materials such as polymers
* Thick polymers, glass or quartz samples
<!--|style="background:WhiteSmoke; color:black"|
* Conductive samples-->
|-
|style="background:LightGrey; color:black" align="center" |Other purpose
|style="background:WhiteSmoke; color:black"| <!-- comment -->
|style="background:WhiteSmoke; color:black"| 
* Surface material analysis using EDX
|style="background:WhiteSmoke; color:black"| 
|style="background:WhiteSmoke; color:black"| 
|style="background:WhiteSmoke; color:black"|
|-
!style="background:silver; color:black;" align="center" width="60"|Instrument location
|style="background:LightGrey; color:black"| 
|style="background:WhiteSmoke; color:black"|
*Basement of building 346
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*Cleanroom of DTU Nanolab in building 346
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*Cleanroom of DTU Nanolab in building 346
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*Cleanroom of DTU Nanolab in building 346
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*Building 451 - room 913
(in the North-East corner of the building's basement)
<!--|style="background:WhiteSmoke; color:black"|
*DTU CEN-->

|-
!style="background:silver; color:black" align="center" valign="center" rowspan="2"|Performance
|style="background:LightGrey; color:black" rowspan="2" align="center" |Resolution
|style="background:Whitesmoke; color:black" colspan="5" align="center"| The resolution of a SEM is strongly dependent on the type of sample and the skills of the operator. The highest resolution is probably only achieved on special samples
|-
|style="background:WhiteSmoke; color:black"|
* 1-2 nm (limited by vibrations)
|style="background:WhiteSmoke; color:black"|
* 1-2 nm (limited by vibrations)
|style="background:WhiteSmoke; color:black"|
* 1-2 nm (limited by vibrations)
|style="background:WhiteSmoke; color:black"|
* 1-2 nm (limited by vibrations)
<!--|style="background:WhiteSmoke; color:black"|
* ~3.5 nm (limited by instrument)-->
|style="background:WhiteSmoke; color:black"|
* ~25 nm (limited by instrument)
|-
!style="background:silver; color:black" align="center" valign="center" rowspan="5"|Instrument specifics
|style="background:LightGrey; color:black" align="center" |Detectors
|style="background:WhiteSmoke; color:black"|
* Secondary electron (Se2)
* Inlens secondary electron (Inlens)
* 4 Quadrant Backscatter electron (QBSD) 
* Variable pressure secondary electron (VPSE)
|style="background:WhiteSmoke; color:black"|
* Secondary electron (Se2)
* Inlens secondary electron (Inlens)
* 4 Quadrant Backscatter electron (QBSD)
* Variable pressure secondary electron (VPSE)
|style="background:WhiteSmoke; color:black"|
* Secondary electron (Se2)
* Inlens secondary electron (Inlens)
* High Definition four quadrant Angular Selective Backscattered electron detector (HDAsB) 
* Variable pressure secondary electron (VPSE)
|style="background:WhiteSmoke; color:black"|
* Secondary electron (Se2)
* Inlens secondary electron (Inlens)
* Inlens backscatter electron (Inlens ESB)
* Retractable, column mounted six segment backscatter electron (aBSD)
* Variable pressure secondary electron (VPSE)
* Retractable, four segment transitted electron (aSTEM)
<!--|style="background:WhiteSmoke; color:black"|
* Secondary electron (Everhart-Thornley (ETD))
* Backscatter electron (BSD) - Add-on
* Large Field Detector (LFD) - Add-on
* CCD camera -->
|style="background:WhiteSmoke; color:black"|
* Secondary electron (SE)
* Backscatter electron (BSE)
|-
|style="background:LightGrey; color:black" align="center" |Stage
|style="background:WhiteSmoke; color:black"|
* X, Y: 130 &times; 130 mm
* T: -4 to 70<sup>o</sup> 
* R: 360<sup>o</sup> 
* Z: 50 mm
|style="background:WhiteSmoke; color:black"|
* X, Y: 150 &times; 150 mm
* T: -10 to 70<sup>o</sup> 
* R: 360<sup>o</sup> 
* Z: 50 mm
|style="background:WhiteSmoke; color:black"|
* X, Y: 130 &times; 130 mm
* T: -4 to 70<sup>o</sup>
* R: 360<sup>o</sup> 
* Z: 50 mm
|style="background:WhiteSmoke; color:black"|
* X, Y: 130 &times; 130 mm
* T: -4 to 70<sup>o</sup>
* R: 360<sup>o</sup> 
* Z: 50 mm
|style="background:WhiteSmoke; color:black"|
* X, Y: 35 mm
* T: No tilt
* R: No rotation
* Z: 0 mm
|-
|style="background:LightGrey; color:black" align="center" |Electron source
|style="background:Whitesmoke; color:black" colspan="4" align="center"| FEG (Field Emission Gun) source
|style="background:WhiteSmoke; color:black"|
* Thermionic tungsten filament
<!--|style="background:WhiteSmoke; color:black"|
* Tungsten filament-->
|-
|style="background:LightGrey; color:black" align="center" |Operating pressures
|style="background:WhiteSmoke; color:black"|
* Fixed at High vacuum (2 &times; 10<sup>-4</sup>mbar - 10<sup>-6</sup>mbar)
* Variable at Low vacuum (0.1 mbar-2 mbar)
|style="background:WhiteSmoke; color:black"|
* Fixed at High vacuum (2 &times; 10<sup>-4</sup>mbar - 10<sup>-6</sup>mbar)
* Variable at Low vacuum (0.1 mbar-2 mbar)
|style="background:WhiteSmoke; color:black"|
* Fixed at High vacuum (2 &times; 10<sup>-4</sup>mbar - 10<sup>-6</sup>mbar)
* Variable at Low vacuum (0.1 mbar-2 mbar)
|style="background:WhiteSmoke; color:black"|
* Fixed at High vacuum (2 &times; 10<sup>-4</sup>mbar - 10<sup>-6</sup>mbar)
* Variable at Low vacuum (0.1 mbar-2 mbar)
** Standard VP (variable pressure): 5-60 Pa
** Nano VP, 350 um beamsleeve aperture: 5-150 PA
** Nano VP, 800 um beamsleeve aperture: 5-40 PA
|style="background:WhiteSmoke; color:black"|
* Conductor vacuum mode: 5 Pa
* Standard vacuum mode: 30 Pa
* Charge-up reduction vacuum mode: 50 Pa
<!--|style="background:WhiteSmoke; color:black"|
* High vacuum and Low vacuum-->
|-
|style="background:LightGrey; color:black" align="center" |Options
|style="background:WhiteSmoke; color:black"|
* All software options available
* Spicer electron magnetic noise cancellations system
|style="background:WhiteSmoke; color:black"|
* Antivibration platform
* Fjeld M-200 airlock taking up to 8" wafers
* Oxford Instruments X-Max<sup>N</sup> 50 mm<sup>2</sup> SDD EDX detector and AZtec software package
|style="background:WhiteSmoke; color:black"|
*High Definition four quadrant Angular Selective Backscattered electron detector (HDAsB)
|style="background:WhiteSmoke; color:black"|
* Antivibration platform
* Spicer electron magnetic noise cancellations system
* Zeiss airlock taking up to 6" wafers
* Plasma cleaner
* Sample bias option
|style="background:WhiteSmoke; color:black"|
<!--|style="background:WhiteSmoke; color:black"|
* Focused ion beam (FIB) (Ga<sup>+</sup> ions)-->
|-
!style="background:silver; color:black" align="center" valign="center" rowspan="3" align="center" |Substrates
|style="background:LightGrey; color:black" align="center" |Sample sizes
|style="background:WhiteSmoke; color:black"|
* Up to 6" wafer with full view 
|style="background:WhiteSmoke; color:black"|
* Up to 8" wafer with 6" view
|style="background:WhiteSmoke; color:black"|
*  Up to 6" wafer with full view
|style="background:WhiteSmoke; color:black"|
*  Up to 6" wafer with full view
|style="background:WhiteSmoke; color:black"|
*  Up to 70 mm with full wiew
<!--|style="background:WhiteSmoke; color:black"|
* Wafers won´t fit without a proper holder. The height of the sample is critical, should be as small, as possible-->
|-
| style="background:LightGrey; color:black" align="center" |Allowed materials
|style="background:WhiteSmoke; color:black"|
* Any standard cleanroom material and samples from the 	Laser Micromachining tool and the Polymer Injection Molding tool
|style="background:WhiteSmoke; color:black"|
* Any standard cleanroom materials
|style="background:WhiteSmoke; color:black"|
* Any standard cleanroom materials
|style="background:WhiteSmoke; color:black"|
* Any standard cleanroom materials
|style="background:WhiteSmoke; color:black"|
* Any standard cleanroom material and samples from the 	Laser Micromachining tool and the Polymer Injection Molding tool
* Some biological samples (ask for permission)
<!--|style="background:WhiteSmoke; color:black"|
* Conductive materials
* No biological samples-->
|- 
|}

<br clear="all" />

==Comparison of the SEMs at DTU Nanolab - building 307/314 [[image:Under_construction.png|50px]]==
{{SEM comparison table 314}}