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=SEM LEO=
=SEM LEO=
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[[Category: Equipment|Thin film]]
[[Category: Thin Film Deposition|ALD]]
== ALD - Atomic layer deposition ==
[[image:ALD.jpg|300x300px|right|thumb|Picosun R200 ALD, positioned in cleanroom F-2.]]
[[image:ALD.jpg|300x300px|right|thumb|Picosun R200 ALD, positioned in cleanroom F-2.]]
The Picosun R200 ALD (atomic layer deposition) tool is used to deposit a very thin layer of Al<sub>2</sub>O<sub>3</sub>,TiO<sub>2</sub> or Pt (not testet yet) on different samples.
A Danchip there are five scanning electron microscopes (SEMs). These SEMs cover a wide range of needs both in the cleanroom and outside: From the fast in-process verification of different process parameters such as etch rates, step coverages or lift-off quality to the ultra high resolution images on any type of sample intended for publication.
Each process is using two different precurcors. The reaction takes place in cycles. During each cycle a very short pulse of each precursor is introduced into the ALD reaction chamber in turns, and in-between each precursor pulse the chamber is purged with nitrogen. All reactions have to take place on the sample surface, thus it is very important that each precurcor is removed from the chamber before the next one is introduced. In that way the ALD layer will be deposited atomic layer by atomic layer.
The SEM LEO was installed in the cleanroom in the 1998, and the software was ungraded in 2012.
In order to ensure that the ALD reactor has the same temperature eveywhere, it has a dual chamber structure. The inner chamber is the ALD reactor with the sample holder, and the outer chamber is a vacuum chamber that is isolating the reactor from room air. The space between the two chambers is called an intermediate space (IMS). The IMS is connected to a nitrogen carrier gas line.
This SEM will cover most users need. It is a very reliable and rugged instrument that provides high quality images of most samples. Excellent images on a large variety of materials such as semiconductors, semiconductor oxides or nitrides, metals, thin films and some polymers may be acquired on the SEM.
When the reactor chamber is heated up or cooled down, it will take some time before the sample holder and the sample reach the desired temperature. Thus, it is important to include a temperature stabilization time in the process recipes.
The SEM is is equipped with a Raith e-beam writing system.
The ALD deposition takes place in the reactor chamber. All precursor and nitrogen carrier gas lines are connected to the reactor chamber through separate gas lines. The percursors pulse time is controlled using special ALD valves, that allow very short precursors pulses to be introduced into the ALD reactor and a at the same time allow a constant nitrogen purge.
The ALD reaction takes place under vacuum, thus a vacuum pump is connected to the bottom of the ALD reactor. The pump is located in the basement.
'''The user manual, the user APV and contact information can be found in LabManager:'''
The liquid precursors (TMA, TiCl4, MeCpPtMe<sub>3</sub> and H<sub>2</sub>O) are located in the cabinet below the ALD chamber. When these precursors are not in use, the manual valves have to be closed. Ozone is generated by use of an ozone generator that is located on the side of the machine.
It is possible to change the sample holder, so that ALD deposition can take place on different samples, e.g. a small wafer batch or a number of smaller samples. Samples are loaded manually into the sample holder by use of a tweezer.
[http://labmanager.dtu.dk/function.php?module=Machine&view=view&mach=37 SEM LEO info page in LabManager],
A short presentation with some information about the ALD tool can be found [[Media:ProcessMeeting ALD 2013-12-06_1.pdf|here]].
'''The user manual, the user APV and contact information can be found in LabManager:'''
[http://labmanager.danchip.dtu.dk/function.php?module=Machine&view=view&mach=321 ALD Picosun R200 info page in LabManager],
A Danchip there are five scanning electron microscopes (SEMs). These SEMs cover a wide range of needs both in the cleanroom and outside: From the fast in-process verification of different process parameters such as etch rates, step coverages or lift-off quality to the ultra high resolution images on any type of sample intended for publication.
The SEM LEO was installed in the cleanroom in the 1998, and the software was ungraded in 2012.
This SEM will cover most users need. It is a very reliable and rugged instrument that provides high quality images of most samples. Excellent images on a large variety of materials such as semiconductors, semiconductor oxides or nitrides, metals, thin films and some polymers may be acquired on the SEM.
The SEM is is equipped with a Raith e-beam writing system.
The user manual, the user APV and contact information can be found in LabManager:
