Specific Process Knowledge/Thin film deposition/Lesker: Difference between revisions

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<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]]
Line 7: Line 9:
== LESKER Sputter Tool==
== LESKER Sputter Tool==


The purpose of the sputter 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 PVD 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.




Line 26: Line 28:
*[[Specific Process Knowledge/Thin film deposition/Deposition of Silver|Silver (Ag)]]
*[[Specific Process Knowledge/Thin film deposition/Deposition of Silver|Silver (Ag)]]
*[[Specific Process Knowledge/Thin film deposition/Deposition of Silicon|Silicon (Si)]]
*[[Specific Process Knowledge/Thin film deposition/Deposition of Silicon|Silicon (Si)]]
*[[Specific Process Knowledge/Thin film deposition/Deposition of NiV/Sputtering of NiV in Lesker|NiV alloy]]
*Iron (Fe)
*Iron (Fe)
*+ many more ([[#List of available targets for the Sputter-System(Lesker) (03 June 2013)|see list below]] or ask)
*+ many more ([[#List of available targets for the Sputter-System(Lesker) (03 June 2013)|see list below]] or ask)


Contact the pvd-group if you have special needs (pvd@danchip.dtu.dk).
Contact the Thin Film group if you have special needs (thinfilm@danchip.dtu.dk).
 
====Sputter rate====
====Sputter rate====
The sputter rate depends on  
The sputter rate depends on  
Line 37: Line 41:
* gas in chamber (Ar, N2, O2 or mixture).
* gas in chamber (Ar, N2, O2 or mixture).


In the tabel below ([[#Relative Sputter rates |Relative Sputter rates]]) there a given a list of relative sputter rates for different materials (Al is set to 1).
In the table below ([[#Relative Sputter rates |Relative Sputter rates]]) there is a list of relative sputter rates for different materials (Al is set to 1).
This means that You can estimate the sputter rate for a new material if you have the rate for another material under the same conditions.
This means that you can estimate the sputter rate for a new material if you have the rate for another material under the same conditions (may only work for non-reactive sputtering, i.e., with Ar as the gas).
I think this only works for non-reactive sputtering (i.e. with Ar as the gas).


==Overview of the performance of Sputter-System(Lesker) and some process related parameters==
====Thickness uniformity====
We have measured the thickness of a TiO<sub>x</sub> film deposited on a 6" Si wafer. The thickness measurement was done in the [[Specific Process Knowledge/Characterization/Optical_characterization#Ellipsometer_VASE_and_Ellipsometer_M-2000V|VASE ellipsometer]].
[[File:TiO2_150mm_13_points_from_lesker_20151103.png|500px|right]]


Deposition parameters were:
{| border="2" cellspacing="0" cellpadding="10"  
{| border="2" cellspacing="0" cellpadding="10"  
|-
|-
!style="background:silver; color:black;" align="left"|Purpose
!style="background:silver; color:black;" align="left"|Recipe
|style="background:LightGrey; color:black"|Deposition of magnetic metals and dielectrica ||style="background:WhiteSmoke; color:black"|
|style="background:WhiteSmoke; color:black"|source 3 with oxygen
*Sputtering of magnetic metals and Silicon
|-
!style="background:silver; color:black;" align="left"|time
|style="background:WhiteSmoke; color:black"|600 s
|-
!style="background:silver; color:black;" align="left"|Gas
|style="background:WhiteSmoke; color:black"|O<sub>2</sub>/Ar Ratio 10/100
|-
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="2"|Performance
!style="background:silver; color:black;" align="left"|Pressure
|style="background:LightGrey; color:black"|Film thickness||style="background:WhiteSmoke; color:black"|
|style="background:WhiteSmoke; color:black"|3 mtorr
*
|-
|-
|style="background:LightGrey; color:black"|Deposition rates
!style="background:silver; color:black;" align="left"| Gun
|style="background:WhiteSmoke; color:black"|
|style="background:WhiteSmoke; color:black"| 3
*
|-
|-
!style="background:silver; color:black" align="left" valign="top" rowspan="3"|Process parameter range
!style="background:silver; color:black;" align="left"|Target
|style="background:LightGrey; color:black"|Process Temperature
|style="background:WhiteSmoke; color:black"|Ti
|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:silver; color:black;" align="left"|Power
|style="background:WhiteSmoke; color:black"|
|style="background:WhiteSmoke; color:black"|200 W
*3-10 mTorr
|-
|-
|style="background:LightGrey; color:black"|Process Gases
!style="background:silver; color:black;" align="left"|Voltage
|style="background:WhiteSmoke; color:black"|
|style="background:WhiteSmoke; color:black"|370V
*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:silver; color:black;" align="left"|Date
|style="background:LightGrey; color:black"|Batch size
|style="background:WhiteSmoke; color:black"|November 3<sup>rd</sup> 2015
|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
|-
|}
|}


Line 96: Line 83:
''By Bjarke Thomas Dalslet @Nanotech.dtu.dk''
''By Bjarke Thomas Dalslet @Nanotech.dtu.dk''


The Lesker CMS 18 sputter system can produce films in a wide range of qualities. The 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.
 
Strain estimations was done on 30 nm Ni<math>_{81}</math>Fe<math>_{19}</math> thin films using low angle x-ray diffraction, for various substrates. It was found that the strain of the film influenced the resistance (R) and anisotropic magneto resistance (AMR) of the films (this relationship is also documented in literature); A Ta interface layer reduced R and increased AMR on both Si and SiO<math>_2</math> substrates while reducing strain.
 
This study was then done on 30 nm Ni<math>_{81}</math>Fe<math>_{19}</math> thin films deposited on 3 nm Ta on top of a SiO<math>_2</math> substrate, using R and AMR as an indication of strain. As seen in the tables, applying a substrate bias increases AMR and conductance (1/R). An equivalent effect is seen when heating the substrate during deposition. This heating can also be done after deposition without loosing the effect.
 
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Name'''
| align="center" style="background:#f0f0f0;"|'''Substrate bias (W)'''
| align="center" style="background:#f0f0f0;"|'''AMR'''
| align="center" style="background:#f0f0f0;"|'''1/R (S)'''
| align="center" style="background:#f0f0f0;"|'''Crystal strain'''
|-
| 0029 NiFe3_stack_RF20||20||0.02724278||1.308044474||
|-
| 0018_NiFe1_stack_RF||10||0.025850358||0.898311175||
|-
| 0030 NiFe3_stack||0||0.020103598||0.71772052||0.8
|-
|}
 
 
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Name'''
| align="center" style="background:#f0f0f0;"|'''Temperature (C)'''
| align="center" style="background:#f0f0f0;"|'''AMR'''
| align="center" style="background:#f0f0f0;"|'''1/R (S)'''
| align="center" style="background:#f0f0f0;"|'''Crystal strain'''
|-
| 0030 NiFe3_stack||25||0.020103598||0.71772052||0.8
|-
| BDT-NiFe1-blank30||200||0.019319002||1.095770327||
|-
| BTD-NiFe-Blank22||250||0.021768497||1.047668937||
|-
| BTD-NiFe-Blank14||300||0.02983617||1.724137931||
|-
| BTD-NiFe-Blank13||350||0.033944331||1.887504719||
|-
| BTD-NiFe-Blank15||400||0.031176801||1.655903295||0.2
|-
| BTD-NiFe-Blank16||450||0.030843457||||
|-
|
|}
 


*[[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 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]]


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).
Other studies on metals (NiFe/MnIr) show only limited effect of the substrate bias on the roughness.


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>.
==Stress in deposited films==


Other studies on metals (NiFe/MnIr)  show only limited effect of the substrate bias on the roughness.
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.
 
 
===From SiO2 target (RF 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'''
|-
| 3||0||0||157||0.902||
|-
| 6||5||0||157||0.499||44
|-
| 7||10||0||157||0.142||42
|-
| 8||15||0||157||0.422||40
|-
|}
 
 
===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" />
 
==Oxide insulation analysis==
''by Bjarke Thomas Dalslet @Nanotech.dtu.dk''
 
The wafers in this analysis consisted of a Si substrate with no native oxide. A layer of SiO<math>_2</math> was reactively sputtered (9% O2 90 W 3.5 mTorr). After that, using a shadow mask, 200nm thick gold rectangles was electro deposited on top of the oxide. Gold was also electro deposited on the back side. Then the impedance as a function of frequency was recorded.
 
The figure shows the measurements for different oxide thicknesses. Most of the measurements show perfect capacitors, although for illustration measurements with a few pinholes and with many pinholes is also shown for the 20 nm sample.  
 
The success rate for the different thicknesses can be seen in the table, together with the number of samples measured and the number of perfect capacitors.
 
It is possible to make perfect capacitors with oxide thicknesses down to and including 5 nm and possibly even thinner, although the failure rate increases. Bear in mind, though that each structure measured here has an area of 8 mm<sup>2</sup> - for a 1 mm<sup>2</sup> structure the failure rate would be much lower, assuming the short circuits are not located on the sides of the structures.
 
 
[[Image:Lesker_Impedance_Bjarke.png|600px|alt text]]
 
 
{| {{table}} border="1" cellspacing="0" cellpadding="8"
| align="center" style="background:#f0f0f0;"|'''Name'''
| align="center" style="background:#f0f0f0;"|'''Thickness [nm]'''
| align="center" style="background:#f0f0f0;"|'''# samples measured'''
| align="center" style="background:#f0f0f0;"|'''# good capacitors'''
| align="center" style="background:#f0f0f0;"|'''Success rate [%]'''
|-
| 38||5||11||1||9
|-
| 39||10||10||2||20
|-
| 40||20||7||3||43
|-
| 41||30||7||7||100
|-
| 37||50||7||7||100
|-
|}


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]].
<br>


==List of available targets for the Sputter-System(Lesker) (03 June 2013)==
==List of available targets for the Sputter-System(Lesker) (03 June 2013)==
Line 276: Line 115:
|style="background:WhiteSmoke; color:black"|'''target thickness'''
|style="background:WhiteSmoke; color:black"|'''target thickness'''
|style="background:WhiteSmoke; color:black"|'''Purity'''
|style="background:WhiteSmoke; color:black"|'''Purity'''
|style="background:WhiteSmoke; color:black"|'''Max. Power (W)'''
|style="background:WhiteSmoke; color:black"|'''Max Ramp up and down (W/s)'''
|-
|-
|Ag||    0,250"|| 99,9%
|Ag||    0,250"|| 99,9% || 314 || 20
|-
|-
||Al|| 0,250"|| 99,99%
||Al|| 0,250"|| 99,99% || 314 || 20
|-
|-
|Au||   0,125"|| 99,999%
|Au||   0,125"|| 99,999% || 314 || 20
|-
|-
|Co|| 0,0625"|| 99,95%
|Cr||   0,125"|| 99,95% || 251 || 20
|-
|-
|Cr||   0,125"|| 99,95%
|Cu|| 0,250"|| 99,99% || 314 || 20
|-
|-
|Cu|| 0,250"|| 99,99%
|Fe|| 0,0625"|| 99,9% || 126 || 10
|-
|-
|Fe|| 0,0625"|| 99,9%
|Ge|| 0,250"|| 99,999% || 126 || 0.5
|-
|-
|Ge|| 0,250"|| 99,999%
|Mg|| 0.250"|| 99,95% || 215 || 20
|-
|-
|Mg|| 0.250"|| 99,95%
|Mo|| 0,250"|| 99,95% || 314 || 20
|-
|-
|Mo|| 0,250"|| 99,95%
|Nb|| 0,250"|| 99,95% || 314 || 20
|-
|-
|Nb|| 0,250"|| 99,95%
|Ni||   0,125"|| 99,9% || 188 || 10
|-
|-
|Ni||   0,125"|| 99,9%
|Pd|| 0,125"|| 99,95% || 251 || 20
|-
|-
|Pd|| 0,125"|| 99,95%
|Pt||   0,125"|| 99,95% || 251 || 20
|-
|-
|Pt||   0,125"|| 99,95%
|Ru||   0,125"|| 99,95% || 314 || 20
|-
|-
|Ru||   0,125"|| 99,95%
|Si, Undoped|| 0,250"|| 99,999% || 126 || 0.5
|-
|-
|Si, Undoped|| 0,250"|| 99,999%
|Ta||   0,250"|| 99,95% || 314 || 20
|-
|-
|Ta||   0,250"|| 99,95%
|Te||   0,250"|| 99,999% || 16 || 0.5
|-
|-
|Te||   0,250"|| 99,999%
|Ti|| 0,250"|| 99,7% || 251 || 20
|-
|-
|Ti|| 0,250"|| 99,7%
|Al2O3|| 0,125" + Cu backing plate|| 99,99% || 63 || 0.5
|-
|-
|Al2O3|| 0,125" + Cu backing plate|| 99,99%
|Al2O3|| 0,250"|| 99,99% || 63 || 0.5
|-
|-
|Al2O3|| 0,250"|| 99,99%
|Al/Cu99,5/0,5%||   0,250"|| 99,99% || 314 || 20
|-
|-
|Al/Cu99,5/0,5%||   0,250"|| 99,99%
|Cr2O3||   0,125" + Cu backing plate|| 99,8% || 63 || 0.5
|-
|-
|Co/Fe  50/50%||   0,0625"|| 99,95%
|Cu/Ti/25%|| 0,125"|| 99,99% || 251 || 20
|-
|-
|Co/Fe 80/20%||   0,0625"|| 99,95%
|Fe/Mn 50/50%|| 0,250"|| 99,95% || 126 || 10
|-
|-
|Co/Fe 90/10%||   0,0625"|| 99,95%
|ITO (In2O3/SnO2) 90/10%|| 0,125"|| 99,99% || 63 || 0.5
|-
|-
|Cr2O3||   0,125" + Cu backing plate|| 99,8%
|Mn/Ir80/20%|| 0,125"|| 99,9% || 251 || 20
|-
|-
|Cu/Ti/25%|| 0,125"|| 99,99%
|MgO||  0,125"|| 99,95% || 63 || 0.5
|-
|-
|Fe/Mn  50/50%|| 0,250"|| 99,95%
|Ni/Co50/50%|| 0,0625"|| 99,95% || 126 || 20
|-
|-
|ITO (In2O3/SnO2)  90/10%||  0,125"|| 99,99%
|Ni/Fe    80/20%|| 0.125"|| 99,95% || 126 || 20
|-
|-
|Mn/Ir80/20%|| 0,125"|| 99,9%
|NiV      93/7%||   0,250"|| 99,95% || 157 || 20
|-
|-
|MgO|| 0,125"|| 99,95%
|SiC ||   0,125" + Cu backing plate|| 99,5% || 63 || 0.5
|-
|-
|Ni/Co50/50%|| 0,0625"|| 99,95%
|Si3N4/MgO 2%||   0,125"|| 99,9% || 63 || 0.5
|-
|-
|Ni/Co  50/50%|| 0,125"|| 99,95%
|SiO2||   0,125"|| 99,995% || 126 || 0.5
|-
|-
|Ni/Fe    80/20%|| 0.125"|| 99,95%
|SiO2||   0,250"|| 99,995% || 126 || 0.5
|-
|-
|NiV      93/7%||   0,250"|| 99,95%
|Ta2O5|| 0,125"|| 99,900% || 63 || 0.5
|-
|-
|Si3N4/MgO 2%||   0,125"|| 99,9%
|AZO (ZnO/Al2O3) 98%/2% ||0,125"|| 99,99% || 126 || 0.5
|-
|-
|SiO2||   0,125"|| 99,995%
|ZnO|| 0.250"|| 99,999% || 63 || 0.5
|-
|-
|SiO2||   0,250"|| 99,995%
|ZrO(2)/Y(2)O(3)|| || 99,900% || 63 || 0.5
|-
|-
|Ta2O5|| 0,125"|| 99,900%
|V|| 0.125"|| 99,500% || 188 || 20
|-
|-
|AZO (ZnO/Al2O3) 98%/2% ||0,125"|| 99,99%
|W|| 0.250"|| 99,500% || 314 || 20
|-
|-
|ZnO|| 0.250"|| 99,999%
|Hf|| 0.125"|| - || 188 || 20
|-
|-
|ZrO(2)/Y(2)O(3)|| || 99,900%
|Sn|| 0.250"|| - || 31 || 0.5
|}
|}
==Relative Sputter rates==
==Relative Sputter rates==
To use these charts, locate the material for which known conditions are available. Then
To use these charts, locate the material for which known conditions are available. Then
Line 461: Line 303:
|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
Line 473: Line 313:
|-
|-
|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.
|-
|}
|}

Latest revision as of 13:51, 22 January 2024

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Unless otherwise stated, this page is written by DTU Nanolab internal

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.

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 Cleanroom D-4. It should always be done in the dedicated lift-off bath in the fumehood next to the sputter system.


The user manual, user APV and contact information can be found in LabManager:

Sputter-System(Lesker) in LabManager


Materials for sputtering

Contact the Thin Film group if you have special needs (thinfilm@danchip.dtu.dk).

Sputter rate

The sputter rate depends on

  • target material
  • gun power (increasing power gives in general higher rate). Be aware of limitations on the power for different materials.
  • chamber pressure (increasing pressure gives in general lower rate). Too low a pressure can make the plasma unstable.
  • gas in chamber (Ar, N2, O2 or mixture).

In the table below (Relative Sputter rates) there is a list of relative sputter rates for different materials (Al is set to 1). This means that you can estimate the sputter rate for a new material if you have the rate for another material under the same conditions (may only work for non-reactive sputtering, i.e., with Ar as the gas).

Thickness uniformity

We have measured the thickness of a TiOx film deposited on a 6" Si wafer. The thickness measurement was done in the VASE ellipsometer.

Deposition parameters were:

Recipe source 3 with oxygen
time 600 s
Gas O2/Ar Ratio 10/100
Pressure 3 mtorr
Gun 3
Target Ti
Power 200 W
Voltage 370V
Date November 3rd 2015

Film quality optimization

By Bjarke Thomas Dalslet @Nanotech.dtu.dk

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.

Surface roughness optimization

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.

The surface roughness dependence on the substrate bias strength can be found in the following pages for:

Other studies on metals (NiFe/MnIr) show only limited effect of the substrate bias on the roughness.

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 NiFe, Si, Cr and Cu films deposited with the Lesker sputter system under a range of circumstances.

Results of the study and links to further reading may be found here:


List of available targets for the Sputter-System(Lesker) (03 June 2013)

Deposition material target thickness Purity Max. Power (W) Max Ramp up and down (W/s)
Ag 0,250" 99,9% 314 20
Al 0,250" 99,99% 314 20
Au 0,125" 99,999% 314 20
Cr 0,125" 99,95% 251 20
Cu 0,250" 99,99% 314 20
Fe 0,0625" 99,9% 126 10
Ge 0,250" 99,999% 126 0.5
Mg 0.250" 99,95% 215 20
Mo 0,250" 99,95% 314 20
Nb 0,250" 99,95% 314 20
Ni 0,125" 99,9% 188 10
Pd 0,125" 99,95% 251 20
Pt 0,125" 99,95% 251 20
Ru 0,125" 99,95% 314 20
Si, Undoped 0,250" 99,999% 126 0.5
Ta 0,250" 99,95% 314 20
Te 0,250" 99,999% 16 0.5
Ti 0,250" 99,7% 251 20
Al2O3 0,125" + Cu backing plate 99,99% 63 0.5
Al2O3 0,250" 99,99% 63 0.5
Al/Cu99,5/0,5% 0,250" 99,99% 314 20
Cr2O3 0,125" + Cu backing plate 99,8% 63 0.5
Cu/Ti/25% 0,125" 99,99% 251 20
Fe/Mn 50/50% 0,250" 99,95% 126 10
ITO (In2O3/SnO2) 90/10% 0,125" 99,99% 63 0.5
Mn/Ir80/20% 0,125" 99,9% 251 20
MgO 0,125" 99,95% 63 0.5
Ni/Co50/50% 0,0625" 99,95% 126 20
Ni/Fe 80/20% 0.125" 99,95% 126 20
NiV 93/7% 0,250" 99,95% 157 20
SiC 0,125" + Cu backing plate 99,5% 63 0.5
Si3N4/MgO 2% 0,125" 99,9% 63 0.5
SiO2 0,125" 99,995% 126 0.5
SiO2 0,250" 99,995% 126 0.5
Ta2O5 0,125" 99,900% 63 0.5
AZO (ZnO/Al2O3) 98%/2% 0,125" 99,99% 126 0.5
ZnO 0.250" 99,999% 63 0.5
ZrO(2)/Y(2)O(3) 99,900% 63 0.5
V 0.125" 99,500% 188 20
W 0.250" 99,500% 314 20
Hf 0.125" - 188 20
Sn 0.250" - 31 0.5

Relative Sputter rates

To use these charts, locate the material for which known conditions are available. Then multiply the rate by the relative factors to arrive at the estimated rate for the new material. For example, with previous data showing 3.5Å/s Aluminum at 100W, then Titanium at similar conditions will generate approximately

(0.53/1.00)·3.5 Å/s ≅ 2 Å/s

The rates in this table are calculated based on a 500V cathode potential. As the power is increased greater than two times the original rate, then the relative rate will drop slightly (up to 10%). For example, Aluminum at 250W

Al250W = 0.9·Al100W·(P1/P0)
0.9·3.5 Å/s·(250/100) ≅ 7.4 Å/s

The rates in the ceramics table assume the use of an RF power supply and account for the partial duty cycle of the RF generator as compared to a DC supply.

Metals and semiconductors

Deposition material name Relative depostion rate
Ag Silver 2.88
Al Aluminum** 1.00
Au Gold 1.74
Be Beryllium 0.21
C Carbon 0.23
Cu Copper 1.42
GaAs Gallium Arsenide {100} 1.03
GaAs Gallium Arsenide {110} 1.03
Ge Germanium 1.50
Mo Molybdenum 0.66
Nb Niobium 0.76
Pd Palladium 1.77
Pt Platinum 1.00
Re Rhenium 0.84
Rh Rhodium 1.16
Ru Ruthenium 0.98
Si Silicon 0.60
Sm Samarium 1.74
Ta Tantalum 0.67
Th Thorium 1.31
Ti Titanium 0.53
V Vanadium 0.50
W Tungsten 0.57
Y Yttrium 1.53
Zr Zirconium 0.88

Oxides and Ceramics

Deposition material name Relative depostion rate
Al2O3 Alumina 0.05
SiC Silicon Carbide 0.22
SiO2 Silicon Dioxide 0.21
TaC Tantalum Carbide 0.09
Ta2O5 Tantalum Pentoxide 0.39

Magnetic Materials

Deposition material name magn. Relative depostion rate
Cr Chromium Med 0.87
Fe Iron High 0.57
Mn Manganese Med 0.14
Ni Nickel Low 0.86
Ni80Fe20 Permalloy High 0.80

Overview of the performance of Sputter-System(Lesker) and some process related parameters

Purpose Deposition of various materials
  • 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.
Performance Film thickness
  • Material dependent but generally up to hundreds of nm
Deposition rates
Process parameter range Process Temperature
Process pressure
  • 3-10 mTorr
Process Gases
  • Ar
  • N2
  • O2
  • 2 % O2 in Ar
  • mixtures of the above
Substrates Batch size
  • chips
  • 4"
  • 6"
Substrate material allowed
  • Silicon wafers
  • and almost any other as long as it does not degas.
  • See cross-contamination sheet [1]
Material allowed on the substrate
  • almost any as long as it does not degas.