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=The Molecular Vapor Deposition Tool =
{{cc-nanolab}}


[[image:Mvd.jpg|200x200px|right|thumb|The MVD is located in cleanroom 1]]
'''Feedback to this page''': '''[mailto:photolith@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/MVD click here]'''


The Applied Microstructures MVD 100 system deposits molecular films on surfaces. These films serve a wide range of purposes ranging from antistiction coatings of nanoimprint lithography stamps to protecting MEMS structures. At Danchip the MVD is essential for nanoimprint lithography.
[[index.php?title=Category:Equipment|Thin film MVD]]
[[index.php?title=Category:Thin Film Deposition|MVD]]


== Processing on the MVD ==
== The Molecular Vapor Deposition tool ==


The MVD coatings are created as self-assembled monolayers on a surface when a molecular vapor of chemials is present.
[[image:Mvd.jpg|200x200px|right|thumb|The MVD is located in cleanroom A-1]]


These chemicals, typically it is flourinated organosilanes, have a teflon-like tail consisting of -(CF<sub>2</sub>)<sub>x</sub>CF<sub>3</sub> and, in the other end, a reactive group -Si<sub>(teflon)</sub>Cl<sub>x</sub>. As shown in the figure below, the chlorine atoms react with -OH groups of the surface to form a chemical bond -Si(<sub>(teflon)</sub>)-O-Si<sub>(surface)</sub>- under elimination of HCL. This means that both Si and SiO<sub>2</sub> surfaces are coated because of the native oxide on Si surfaces.  
The Applied Microstructures MVD 100 system deposits molecular films on surfaces. These films serve a wide range of purposes ranging from antistiction coatings of nanoimprint lithography stamps to protecting MEMS structures. At DTU Nanolab the MVD is an essential tool for nanoimprint lithography, where it is used to create antistiction coatings on the imprint stamps.


<gallery caption="Some chemicals of the MVD and the surface reaction" widths="200px" heights="150px" perrow="2">
'''As per Jan 2025 the O2 plasma is no longer possible to use, we recommend to use a plasma asher before use and then run Flat2NP and Stamp2NP respectively, where NP is for No Plasma. - rkc'''
image:chlorosilanes.jpg|Different chemicals for the MVD.
image:MVDsurfacereaction.jpg|The chemical reaction in which the Cl atoms of the precursors are eliminated under formation of HCl.
</gallery>


== The parameters of the MVD process ==


The most important parameters to control during the MVD process are:


; Substrate surface
'''The user manual, user APV, and contact information can be found in LabManager:'''
: A O<sub>2</sub> plasma is run prior to any process in order to condition the substrate surface. This will also remove any existing MVD coating.


; Water content
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=199 MVD in LabManager]
: Water will cause the chemicals to polymerize (bond to each other instead of on the surface) and it is therefore critical to precisely  control the water content.


; Substrate temperature
==Process information==
: The temperature of the substrate is the same as the process chamber and it is kept constant at 35 <sup>o</sup>C.
*[[Specific Process Knowledge/Thin film deposition/Antistiction Coating|Processing on the MVD]]
*[[Specific Process Knowledge/Thin film deposition/Antistiction Coating#The FLAT recipe|The FLAT recipe]]
*[[Specific Process Knowledge/Thin film deposition/Antistiction Coating#The STAMP recipe|The STAMP recipe]]


; Vapor order
: There is no active force that injects the chemicals into the process chamber. The driving force is a combination of two factors:
# '''A pressure gradient''' The vapor pressure of the chemical (when stored at some temperature in the cylinder) compared to the pressure in the chamber.
#'''A temperature gradient''' The chemical and the line that feeds the process chamber are kept at a higher temperature.
It is critical that the chemicals with the lowest vapor pressure are injected first into the process chamber. If, for instance, water is injected before FDTS, the water will flow into the FTDS expansion volume and cause polymerization, thus forcing a mechanical clean. NOT GOOD!.


== The FLAT recipe ==
== Equipment performance and process related parameters ==


The FLAT recipe is designed for coating of non-structured wafers. The amount of FDTS is delivered in one cycle (4 injections of FDTS at 0.400 Torr + 1 injection of water at 18 Torr) and the reaction time is 15 minutes.
{| border="2" cellspacing="0" cellpadding="2"  
{| border="2" cellpadding="2" cellspacing="1"  
 
|+'''The FLAT recipe'''
!style="background:silver; color:black;" align="center" width="60"|Purpose
|style="background:LightGrey; color:black"|
|style="background:WhiteSmoke; color:black"|
*FDTS coating of Si or SiO2 surfaces
*Indirect O2 plasma treatment
|-
|-
! rowspan="3" align="center"| O<sub>2</sub> plasma
!style="background:silver; color:black;" align="center" width="60"|Vapor sources
! Flow
|style="background:LightGrey; color:black"|Line
| 200 sccm
*1
*2
*3
*4
|style="background:WhiteSmoke; color:black"|Chemical
*Water
*FDTS (new source, 2013)
*FDTS (old source, contaminated line)
*Available (line probably contaminated, no source heater)
|-
|-
! Power
!style="background:silver; color:black" align="center" valign="center" rowspan="1"|Performance
| 250 Watts
|style="background:LightGrey; color:black"|Contact angle
|style="background:WhiteSmoke; color:black" align="center"|
110° (water)
|-
|-
! Time
!style="background:silver; color:black" align="center" valign="center" rowspan="3"|Process parameters
| 300 seconds
|style="background:LightGrey; color:black"|Base pressure
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
20 mTorr
|-
|-
! rowspan="4" align="center"| Chemical # 1 (vapor order 1)
|style="background:LightGrey; color:black"|Chamber temperature
! Name
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
| FDTS
35°C
|-
|-
! Line no.
|style="background:LightGrey; color:black"|Chamber volume
| 3
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
Approx. 3 liters
|-
|-
! Cycles
!style="background:silver; color:black" align="center" valign="center" rowspan="3"|Substrates
| 4
|style="background:LightGrey; color:black"|Substrate size
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
1" to 8"
 
Smaller samples may be processed if fixed to a carrier
|-
|-
! Pressure
| style="background:LightGrey; color:black"|Allowed materials
| 0.500 Torr
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
|-
All cleanroom materials except steel and other ferrous materials
! rowspan="4" align="center"| Chemical # 2 (vapor order 2)
! Name
| Water
|-
! Line no.
| 1
|-
! Cycles
| 1
|-
! Pressure
| 18 Torr
|-
! Processing
! Time
| 900 seconds
|-
! Purge
! Cycles
| 5
|-
|-
|style="background:LightGrey; color:black"|Batch
|style="background:WhiteSmoke; color:black" align="center" colspan="2"|
One sample at a time
Two 4" or 6" wafers may be processed simultaneously using cassettes
|-
|}
|}


 
<br clear="all" />
== The STAMP recipe ==
 
The STAMP recipe uses the same total amount of FDTS as FLAT but delivers it much slower in order to obtain a much better and conformal coating of fine nanostructures. A cycle with 1 injection of FDTS at 0.400 Torr + 1 injection of water at 6 Torr reacts for 15 minutes. Then the process chamber is evacuated and a new cycle starts until 4 cycles are completed.
 
{| border="2" cellpadding="2" cellspacing="1"
|+'''The STAMP recipe'''
|-
|rowspan="3" align="center"|
! rowspan="3" align="center"| O<sub>2</sub> plasma
! Flow
| 200 sccm
|-
! Power
| 250 Watts
|-
! Time
| 300 seconds
|-
! rowspan="10" align="center"| Repeated 4 times
! rowspan="4" align="center"| Chemical # 1 (vapor order 1)
! Name
| FDTS
|-
! Line no.
| 3
|-
! Cycles
| 4
|-
! Pressure
| 0.500 Torr
|-
! rowspan="4" align="center"| Chemical # 2 (vapor order 2)
! Name
| Water
|-
! Line no.
| 1
|-
! Cycles
| 1
|-
! Pressure
| 18 Torr
|-
! Processing
! Time
| 900 seconds
|-
! Purge
! Cycles
| 5
|-
|}
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