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== The Molecular Vapor Deposition tool ==
'''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]'''
[[image:Mvd.jpg|200x200px|right|thumb|The MVD is located in cleanroom 1]]
[[Category: Equipment|Thin film MVD]]
[[Category: Thin Film Deposition|MVD]]
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.
== The Molecular Vapor Deposition tool ==
== Processing on the MVD ==
[[image:Mvd.jpg|200x200px|right|thumb|The MVD is located in cleanroom A-1]]
The MVD coatings are created as self-assembled monolayers on a surface when a molecular vapor of chemials is present.
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.
These chemicals, typically 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 Si<sub>(surface)</sub>-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.
<gallery caption="Some chemicals of the MVD and the surface reaction" widths="200px" heights="150px" perrow="2">
'''The user manual, user APV, and contact information can be found in LabManager:'''
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 ==
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=199 MVD in LabManager]
The most important parameters to control during the MVD process are:
==Process information==
*[[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]]
; Substrate surface
: An 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
== Equipment performance and process related parameters ==
: 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
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: The temperature of the substrate is the same as the process chamber and it is kept constant at 35 <sup>o</sup>C.
: There is no active force that injects the chemicals into the process chamber. The driving force is a combination of two factors:
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# '''A pressure gradient''' The vapor pressure of the chemical (when stored at some temperature in the cylinder) compared to the pressure in the chamber.
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#'''A temperature gradient''' The chemical and the line that feeds the process chamber are kept at a higher temperature.
*FDTS coating of Si or SiO2 surfaces
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!.
*Indirect O2 plasma treatment
== The FLAT recipe ==
=== Purpose ===
The FLAT recipe is designed for quick coating of non-structured wafers. One should not expect to get good conformal coverage of nanostructures or nanometersized surface roughness.
=== Process description ===
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. The total process time is some 22 minutes.
Two 4" or 6" wafers may be processed simultaneously using cassettes
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== The STAMP recipe ==
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=== Purpose ===
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. STAMP should always be used for stamps for nanoimprint lithography irregardless of the feature size.
=== Process description ===
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. This gives a total process time of some 80 minutes.
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.
The user manual, user APV, and contact information can be found in LabManager:
