Specific Process Knowledge/Thin film deposition/Lesker

From LabAdviser
Jump to navigation Jump to search

Feedback to this page: click here

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

Lesker 2014 with text2.jpg

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.

TiO2 150mm 13 points from lesker 20151103.png

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.
Retrieved from "https://labadviser.nanolab.dtu.dk//index.php?title=Specific_Process_Knowledge/Thin_film_deposition/Lesker&oldid=48893"