Archive
Untersuchungen zu Schichteigenschaften der thermischen und plasma-gestützten Atomlagenabscheidung von Metallen
Art der Abschlussarbeit
Diplomarbeit
Autoren
- Hampel, Nils Alexander
Betreuer
- Prof. Dr. rer. nat. Johann Wolfgang Bartha
- Dipl.-Ing. Sebastian Killge
- Dipl.-Ing. Johanna Reif
Abstract
To fabricate electrical through silicon vias, barrier and seed layers are necessary for a following
electric-chemical deposition of copper. Thicknesses of said layers measure only a few nanometers
while their aspect ratio is high. Therefore the atomic layer deposition (ALD) seems promising for the
production of barrier-seed-layer-systems. The ALD is a method of the chemical vapor deposition to
create ultra-thin and highly conform layers.
In this diploma thesis the thermal and plasma-enhanced ALD of metals, which seem 1tting for
creating barrier-seed-layer-systems, will be studied using in-situ and in-vacuo measurement methods.
The in2uence of process parameters on the deposited layers will be analyzed in order to 1nd suitable
settings for creating barrier-seed-layer-systems.
Therefore the literature is studied to examine the application of tantalumnitride-ruthenium-layersystems,
tantalum-rich layers and cobalt layers as barrier-seed-layer-systems. Using the acquired
knowledge, ALD processes are performed in which tantalumnitride-ruthenium-layer-systems and
cobalt layers are deposited. Thermal ALD processes are executed, utilizing TBTDET with ammonia in
case of the tantalumnitride layers and ECPR, oxygen and hydrogen in case of the ruthenium layers.
Those experiments follow the parameters of a process which has already been developed by the
IHM and are performed to later be compared to the cobalt layers. At a temperature of 250 C the
layer system exhibits a sheet resistance of around 31
= while having a thickness of 13nm and a
roughness in the range of the substrate’s one. It can therefore be utilized as a seed layer. At thicker
ruthenium layers partially delamination occurs.
The cobalt layers are deposited by a plasma-enhanced ALD using CpCoCO2. Processes utilizing
hydrogen-, ammonia- and a combination of hydrogen- and nitrogen-plasma are compared. Processes
utilizing a ammonia-plasma have at a temperature of 200 C the purest layers with 74 at.% cobalt.
However their sheet resistance of around 59
= with a thickness of 22nm is too high for a seed
layer. Lower temperatures positively affect the purity of hydrogen-plasma processes, but slow down
their growth. The cobalt layers display a high adhesion and even at high thicknesses no delamination
occurs.
electric-chemical deposition of copper. Thicknesses of said layers measure only a few nanometers
while their aspect ratio is high. Therefore the atomic layer deposition (ALD) seems promising for the
production of barrier-seed-layer-systems. The ALD is a method of the chemical vapor deposition to
create ultra-thin and highly conform layers.
In this diploma thesis the thermal and plasma-enhanced ALD of metals, which seem 1tting for
creating barrier-seed-layer-systems, will be studied using in-situ and in-vacuo measurement methods.
The in2uence of process parameters on the deposited layers will be analyzed in order to 1nd suitable
settings for creating barrier-seed-layer-systems.
Therefore the literature is studied to examine the application of tantalumnitride-ruthenium-layersystems,
tantalum-rich layers and cobalt layers as barrier-seed-layer-systems. Using the acquired
knowledge, ALD processes are performed in which tantalumnitride-ruthenium-layer-systems and
cobalt layers are deposited. Thermal ALD processes are executed, utilizing TBTDET with ammonia in
case of the tantalumnitride layers and ECPR, oxygen and hydrogen in case of the ruthenium layers.
Those experiments follow the parameters of a process which has already been developed by the
IHM and are performed to later be compared to the cobalt layers. At a temperature of 250 C the
layer system exhibits a sheet resistance of around 31
= while having a thickness of 13nm and a
roughness in the range of the substrate’s one. It can therefore be utilized as a seed layer. At thicker
ruthenium layers partially delamination occurs.
The cobalt layers are deposited by a plasma-enhanced ALD using CpCoCO2. Processes utilizing
hydrogen-, ammonia- and a combination of hydrogen- and nitrogen-plasma are compared. Processes
utilizing a ammonia-plasma have at a temperature of 200 C the purest layers with 74 at.% cobalt.
However their sheet resistance of around 59
= with a thickness of 22nm is too high for a seed
layer. Lower temperatures positively affect the purity of hydrogen-plasma processes, but slow down
their growth. The cobalt layers display a high adhesion and even at high thicknesses no delamination
occurs.
Schlagwörter
-
Berichtsjahr
2019