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'''Feedback to this page''': '''[mailto:labadviser@danchip.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.danchip.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/Lesker click here]'''
'''Feedback to this page''': '''[mailto:labadviser@danchip.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.danchip.dtu.dk/index.php/Specific_Process_Knowledge/Thin_film_deposition/Lesker click here]'''
<i> Unless otherwise stated, this page is written by <b>DTU Nanolab internal</b></i>


[[Category: Equipment|Thin film Sputter deposition Lesker]]
[[Category: Equipment|Thin film Sputter deposition Lesker]]
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== LESKER Sputter Tool==
== LESKER Sputter Tool==


The purpose of the "Sputter-system (Lesker)" is to deposit magnetic metals and dielectrica on a single 4" or 6" wafer at a time.
The purpose of the Sputter-System (Lesker) is to deposit magnetic metals and dielectrica on a single 4" or 6" wafer at a time.


It can be a problem to take wafers from the sputter and into the other machines in the cleanroom, since it is not very clean. In principle the sputter should be the last step before you take your wafers out of the cleanroom. If you need to take process your wafers further please contact the Thin Film group so they can help you.
It can be a problem to take wafers from the sputter system and into the other machines in the cleanroom since the sputter system is not very clean. In principle sputtering should therefore be the last step before you take your wafers out of the cleanroom. If you need to process your wafers further please contact the Thin Film group so they can help you.


Lift-off of magnetic materials should never be done in the normal lift-off bath in RR4. It should always be done in the dedicated lift-off bath in the fumehood next to the sputter.
Lift-off of magnetic materials should never be done in the normal lift-off bath in Cleanroom D-4. It should always be done in the dedicated lift-off bath in the fumehood next to the sputter system.




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|-
|-
|}
|}
==Overview of the performance of Sputter-System(Lesker) and some process related parameters==
{| border="2" cellspacing="0" cellpadding="10"
|-
!style="background:silver; color:black;" align="left"|Purpose
|style="background:LightGrey; color:black"|Deposition of magnetic metals and dielectrica ||style="background:WhiteSmoke; color:black"|
*Sputtering of magnetic metals and Silicon
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="2"|Performance
|style="background:LightGrey; color:black"|Film thickness||style="background:WhiteSmoke; color:black"|
*
|-
|style="background:LightGrey; color:black"|Deposition rates
|style="background:WhiteSmoke; color:black"|
*
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Process parameter range
|style="background:LightGrey; color:black"|Process Temperature
|style="background:WhiteSmoke; color:black"|
* usually room temp
* Sample can be heated to more than 400&deg;C *
|-
|style="background:LightGrey; color:black"|Process pressure
|style="background:WhiteSmoke; color:black"|
*3-10 mTorr
|-
|style="background:LightGrey; color:black"|Process Gases
|style="background:WhiteSmoke; color:black"|
*Ar
*N<math>_2</math>
*O<math>_2</math>
*2%O<math>_2</math> in Ar
* mixtures of the above
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Substrates
|style="background:LightGrey; color:black"|Batch size
|style="background:WhiteSmoke; color:black"|
*chips
*4"
*6"
|-
| style="background:LightGrey; color:black"|Substrate material allowed
|style="background:WhiteSmoke; color:black"|
*Silicon wafers
*and almost any other
|-
| style="background:LightGrey; color:black"|Material allowed on the substrate
|style="background:WhiteSmoke; color:black"|
*almost any
|-
|}
''*'' For temperatures above 400&deg;C, please contact thinfilm@danchip.dtu.dk, as higher temperatures may damage the machine.


==Film quality optimization==
==Film quality optimization==
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The Lesker CMS 18 sputter system can produce films in a wide range of crystalline qualities. The crystalline quality of a film depends strongly on the substrate (lattice matching), but also on the energy the sputtered material can utilize for annealing.
The Lesker CMS 18 sputter system can produce films in a wide range of crystalline qualities. The crystalline quality of a film depends strongly on the substrate (lattice matching), but also on the energy the sputtered material can utilize for annealing.


You will find detailed information on film quality optimization for NiFe films [[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_NiFe|here]].
*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_NiFe|Film quality optimization for NiFe films]].


==Surface roughness optimization==
==Surface roughness optimization==
''By Bjarke Thomas Dalslet @Nanotech.dtu.dk''
''By Bjarke Thomas Dalslet @Nanotech.dtu.dk''


The Lesker CMS 18 sputter system provides thin films of varying surface roughness. This roughness was verified to be dependent on the sputtered material, sputter mode (DC or RF) and the substrate bias strength. Other probable factors include sputter power and pressure. Below is a table for three cases.
The Lesker CMS 18 sputter system provides thin films of varying surface roughness. This roughness was verified to be dependent on the sputtered material, sputter mode (DC or RF) and the substrate bias strength. Other probable factors include sputter power and pressure.  
 
The "From SiO<math>_2</math> target (RF sputter)" study was done on clean Si substrates. The sputter power was 157W and the pressure 3.5 mTorr using RF sputtering of a SiO<math>_2</math> target. The film thicknesses were around 42 nm.
 
The "From Si target (DC sputter)" study was done on clean Si substrates. The sputter pressure 3 mTorr using DC reactive sputtering of a Si target. Oxygen was added to the argon sputter gas. Above 10% O<math>_2</math> the gun seems to oxidize (at this sputter power). Figure 1 shows the difference in AFM images between no RF bias (wafer 12) and RF bias (Wafer 21).
 
The "Ta" study was done on clean Si substrates. The sputter pressure was 3 mTorr using DC sputtering of a Ta target. Some O<math>_2</math> was added to wafer 25 and 26 to make Ta<math>_2</math>O<math>_5</math>. In order to get fully oxidized films, up to 30-45% O<math>_2</math> should be added. Consult the thesis of Carsten Christensen for details on Ta<math>_2</math>O<math>_5</math>.


Other studies on metals (NiFe/MnIr)  show only limited effect of the substrate bias on the roughness.
The surface roughness dependence on the substrate bias strength can be found in the following pages for:
*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Silicon_Oxide/Deposition_of_Silicon_Oxide_using_Lesker_sputter_tool|SiO<sub>2</sub>]]
*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Silicon/Si_sputter_in_Sputter-System_Lesker|Si]]
*[[Specific_Process_Knowledge/Thin_film_deposition/Deposition_of_Tantalum/Sputtering_of_Ta|Ta]]


 
Other studies on metals (NiFe/MnIr) show only limited effect of the substrate bias on the roughness.
===From Si target (DC sputter)===
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Wafer nr'''
| align="center" style="background:#f0f0f0;"|'''RF bias (W)'''
| align="center" style="background:#f0f0f0;"|'''Reactive O2 (%)'''
| align="center" style="background:#f0f0f0;"|'''Power(W)'''
| align="center" style="background:#f0f0f0;"|'''Rq (RMS) (nm)'''
| align="center" style="background:#f0f0f0;"|'''Thickness'''
|-
| 12||0||5||135||1.44||123 nm (ellipsometry)
|-
| 13||0||9||130||1.32||98 nm (ellipsometry)
|-
| 14||0||13||100||1.37||71.5 nm (ellipsometry)
|-
| 15||10||9||90||0.984||56.25 nm (ellipsometry)
|-
| 21||20||9||90||0.112||
|-
| 22||15||9||90||0.509||
|-
|}
 
 
===Ta===
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Wafer nr'''
| align="center" style="background:#f0f0f0;"|'''RF bias (W)'''
| align="center" style="background:#f0f0f0;"|'''Reactive O2 (%)'''
| align="center" style="background:#f0f0f0;"|'''Power(W)'''
| align="center" style="background:#f0f0f0;"|'''Rq (RMS) (nm)'''
| align="center" style="background:#f0f0f0;"|'''Thickness'''
|-
| blank1||0||0||180||0.209||
|-
| 16||10||0||180||0.36||56
|-
| 24||20||0||180||0.357||
|-
| 25||20||9||180||0.202||110
|-
| 26||20||5||180||0.194||95
|-
| 27||15||0||180||0.413||
|-
| 28||25||0||180||0.164||
|-
| 31||30||0||180||0.3||
|-
|}
 
 
[[Image:Lesker_roughness_Bjarke.JPG|left|600px|thumb|Figure 1:Left: no RF bias (wafer 12) gives high roughness. Right: RF bias (Wafer 21) gives low roughness]]
 
<br clear="all" />


==Stress in deposited films==
==Stress in deposited films==


Sputter deposition causes stress in the deposited material. Depending on the sputter parameters, the stress can be either tensile or compressive. In 2017 Radu Malureanu investigated the stress in Si, Cr and Cu films deposited with the Lesker sputter system under a range of circumstances.
Sputter deposition causes stress in the deposited material. Depending on the sputter parameters, the stress can be either tensile or compressive. In 2017 Radu Malureanu investigated the stress in NiFe, Si, Cr and Cu films deposited with the Lesker sputter system under a range of circumstances.


Results of the study may be found here:
Results of the study and links to further reading may be found here:
*[[Specific Process Knowledge/Thin film deposition/Lesker/Stress dependence on sputter parameters in the Lesker sputter system|Stress dependence on sputter parameters]].
*[[Specific Process Knowledge/Thin film deposition/Lesker/Stress dependence on sputter parameters in the Lesker sputter system|Stress dependence on sputter parameters]].
 
<br>
<br>


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|-
|-
|Au||   0,125"|| 99,999% || 314 || 20
|Au||   0,125"|| 99,999% || 314 || 20
|-
|Co|| 0,0625"|| 99,95% || 126 || 10
|-
|-
|Cr||   0,125"|| 99,95% || 251 || 20
|Cr||   0,125"|| 99,95% || 251 || 20
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|-
|-
|Al/Cu99,5/0,5%||   0,250"|| 99,99% || 314 || 20
|Al/Cu99,5/0,5%||   0,250"|| 99,99% || 314 || 20
|-
|Co/Fe  50/50%||   0,0625"|| 99,95% || 126 || 10
|-
|Co/Fe  80/20%||   0,0625"|| 99,95% || 126 || 10
|-
|Co/Fe  90/10%||   0,0625"|| 99,95% || 126 || 10
|-
|-
|Cr2O3||   0,125" + Cu backing plate|| 99,8% || 63 || 0.5
|Cr2O3||   0,125" + Cu backing plate|| 99,8% || 63 || 0.5
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|-
|-
|Ni/Co50/50%|| 0,0625"|| 99,95% || 126 || 20
|Ni/Co50/50%|| 0,0625"|| 99,95% || 126 || 20
|-
|Ni/Co  50/50%|| 0,125"|| 99,95% || 126 || 20
|-
|-
|Ni/Fe    80/20%|| 0.125"|| 99,95% || 126 || 20
|Ni/Fe    80/20%|| 0.125"|| 99,95% || 126 || 20
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|style=background:WhiteSmoke; color:black|'''magn.'''
|style=background:WhiteSmoke; color:black|'''magn.'''
|style=background:WhiteSmoke; color:black|'''Relative depostion rate'''
|style=background:WhiteSmoke; color:black|'''Relative depostion rate'''
|-
|Co||Cobalt||Low||0.73
|-
|-
|Cr||Chromium||Med||0.87
|Cr||Chromium||Med||0.87
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|Ni80Fe20||Permalloy||High||0.80
|Ni80Fe20||Permalloy||High||0.80
|}
|}
==Overview of the performance of Sputter-System(Lesker) and some process related parameters==
{| border="2" cellspacing="0" cellpadding="10"
|-
!style="background:silver; color:black;" align="left"|Purpose
|style="background:LightGrey; color:black"|Deposition of various materials ||style="background:WhiteSmoke; color:black"|
* Metals including alloys and magnetic materials
* Dielectrica including silica and alumina.
* Semiconductors including silicon
* See tables above and ask staff if there is a material you would like to deposit which you do not see listed.
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="2"|Performance
|style="background:LightGrey; color:black"|Film thickness||style="background:WhiteSmoke; color:black"|
*Material dependent but generally up to hundreds of nm
|-
|style="background:LightGrey; color:black"|Deposition rates
|style="background:WhiteSmoke; color:black"|
*See [[#Relative Sputter rates |table]] above
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Process parameter range
|style="background:LightGrey; color:black"|Process Temperature
|style="background:WhiteSmoke; color:black"|
* usually room temp
* We used to have sample heating to to more than 400&deg;. However, this is not possible at the moment.
* For sputtering with sample heating, please see [[Specific Process Knowledge/Thin film deposition/Cluster-based multi-chamber high vacuum sputtering deposition system|Sputter-system Metal-Oxide (PC1) and Sputter-system Metal-Nitride (PC3) ]]
|-
|style="background:LightGrey; color:black"|Process pressure
|style="background:WhiteSmoke; color:black"|
*3-10 mTorr
|-
|style="background:LightGrey; color:black"|Process Gases
|style="background:WhiteSmoke; color:black"|
*Ar
*N<sub>2</sub>
*O<sub>2</sub>
*2 % O<sub>2</sub> in Ar
* mixtures of the above
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Substrates
|style="background:LightGrey; color:black"|Batch size
|style="background:WhiteSmoke; color:black"|
*chips
*4"
*6"
|-
| style="background:LightGrey; color:black"|Substrate material allowed
|style="background:WhiteSmoke; color:black"|
*Silicon wafers
*and almost any other as long as it does not degas.
*See cross-contamination sheet [https://labmanager.dtu.dk/function.php?module=XcMachineaction&view=edit&MachID=244]
|-
| style="background:LightGrey; color:black"|Material allowed on the substrate
|style="background:WhiteSmoke; color:black"|
*almost any as long as it does not degas.
|-
|}
==Maximum Power Calculation==
* <math>PD</math> - Power density (fundamental constant given by a supplier)
* <math>P(W)</math> - Power (W) from power supply
* <math>A(inch^2)</math> - Area of the target
------------------------------------------------------------------------------------------------------------
<math> PD=\frac{P(W)}{A(inch^2)}</math>  &#8658;    <math>P(W)=PD\cdot A(inch^2)=PD\cdot\frac{\pi d^2}{4}</math>
<ul>
<li><p> <b><span style="color: green">d=2" (2-inch target)</span></b> <math>P(W)=3.14\cdot PD</math>  </p></li>
<li><p> <b><span style="color: green">d=3" (3-inch target)</span></b> <math>P(W)=7.065\cdot PD</math>  </p></li>
<li><p> <b><span style="color: green">d=4" (4-inch target)</span></b> <math>P(W)=12.56\cdot PD</math>  </p></li>
<li><p> <b><span style="color: green">d=6" (6-inch target)</span></b> <math>P(W)=28.26\cdot PD</math>  </p></li>
</ul>
--------------------------------------------------
Value of the <math>PD</math> is material dependent and can be found on KJLC homepage
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