Area-selective Ru ALD by aC modification using H plasma ...€¦ · PUBLIC Ivan Zyulkova,b,...

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PUBLIC Ivan Zyulkov a,b , Ekaterina Voronina c,d , Mikhail Krishtab a,b , Dmitry Voloshin d , BT Chan b ,Yuriy Mankelevich d , Tatyana Rakhimova d , Silvia Armini b and Stefan De Gendt a,b Area-selective Ru ALD by aC modification using H plasma: from atomistic modelling to sub 50 nm patterned structures a KU Leuven, Department of Chemistry, Faculty of Science, B-3001 Leuven, Belgium. b Imec, Kapeldreef 75, B-3001 Leuven, Belgium. c Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory, GSP-1, Moscow 119991, Russian Federation. d Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Leninskie gory, GSP-1, Moscow 119991, Russian Federation.

Transcript of Area-selective Ru ALD by aC modification using H plasma ...€¦ · PUBLIC Ivan Zyulkova,b,...

Page 1: Area-selective Ru ALD by aC modification using H plasma ...€¦ · PUBLIC Ivan Zyulkova,b, Ekaterina Voroninac,d, Mikhail Krishtaba,b, Dmitry Voloshind, BT Chanb, Yuriy Mankelevichd,

PUBLIC

Ivan Zyulkova,b, Ekaterina Voroninac,d, Mikhail Krishtaba,b, Dmitry Voloshind, BT Chanb, Yuriy Mankelevichd,

Tatyana Rakhimovad, Silvia Arminib and Stefan De Gendta,b

Area-selective Ru ALD by aC modification using H plasma:

from atomistic modelling to sub 50 nm patterned structures

a KU Leuven, Department of Chemistry, Faculty of Science, B-3001 Leuven, Belgium.b Imec, Kapeldreef 75, B-3001 Leuven, Belgium.c Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory, GSP-1, Moscow 119991, Russian Federation.d Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Leninskie gory, GSP-1, Moscow 119991, Russian Federation.

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Briggs, Basoene, Ivan Zyulkov, and Katia Devriendt, "Method of patterning target layer."

U.S. Patent Application No. 15/975,611.

Advanced patterning- tone-inversion

Sacrificial

material

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PVD Cu deposition without (left) and with (right) Ru liner Ishizaka, Tadahiro, et al., Microelectronic Engineering 92 (2012): 76-78

3-dimensional model for low-pressure chemical vapor deposition step coverage in trenches and circular vias, M. Islamraja, et al., J. Appl. Phys., Volume 70, 1991, 7137

Filling of narrow structures

▪ Bottom-up metal deposition can be used for defect-free fill

▪ BU requires selectivity to the trench bottom vs sidewall material

Conventional top-down depositionBottom-up deposition

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Amorphous carbon film –ALD inhibitor Amorphous carbon (aC) film

Ru

aC

SiCN

10 seconds H2 plasma pre-treatment:

ELD Cu

Zyulkov Ivan, et al., Joint EuroCVD 21 – Baltic ALD 15

Conference Linköping, Sweden, 11 – 14 June, 2017.

Robertson, J. "Material science and

engineering." R 37 (2002): 129.

• Amorphous carbon films are commonly used as pattern transfer layers

sp2/ sp3 hydrogenated carbon

• Amorphous carbon can be used as a sacrificial dielectric for low-k replacement

L. Zhang, J. F. De Marneffe, N. Heylen, G. Murdoch, Z. Tokei, J.

Boemmels, S. De Gendt, M. R. Baklanov, Appl. Phys. Lett. 2015,

092901.

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Intrinsic selectivity aC vs SiCN/ low-k

aC

SiCN/ low-k

aC

SiCN/ low-k

H2 plasma pre-treatment

+

ambient

SiOx surface, hydrophilic

Hydrophobic surface,

CH2/CH3 passivation

Zyulkov, Ivan, et al. "Selective Ru ALD as a catalyst for sub-seven-

nanometer bottom-up metal interconnects." ACS applied materials &

interfaces 9.36 (2017): 31031-31041.

Non-growth area

Growth area

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ASD ALD Ru IMEC 10 seconds H2 plasma pre-treatment:

Zyulkov Ivan, et al., Joint EuroCVD 21 – Baltic

ALD 15 Conference Linköping, Sweden, 11 –

14 June, 2017.

ALD Ru

H2 plasma results in ALD Ru inhibition on aC vs SiCN

Downsides:

• ALD Ru defectivity

• aC etch (50 nm / min)

aC

SiCN

aC

SiCN

aC

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ASD ALD Ru IMEC 10 seconds H2 plasma pre-treatment:

Zyulkov Ivan, et al., Joint EuroCVD 21 – Baltic

ALD 15 Conference Linköping, Sweden, 11 –

14 June, 2017.

ALD Ru

H2 plasma results in ALD Ru inhibition on aC vs SiCN

Master-plan:

N-free etch of aC

aC pre-

treatment by

H radicals

ASD

ALD of Ru

MD

modeling of

aC

modification

in H2 plasma

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Remote He/H2 etch of aC (hydrogen radicals only)

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SE measurements of aC etch

• The etch rate is close to zero @ 65

• Clear etch rate increase is observed with the etch

process temperature increase, which indicates C-C

bonds breaking

• Activation energy ~ 28.4 kJ/mol

• Etch is performed in He/H2 plasma

2000 W

• Only radials can reach the sample

surface due to the tool

configuration (downstream plasma

source)

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Remote He/H2 etch of aC (hydrogen radicals only)

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Pristine aC WCA is 67.5 ± 1.6 degrees

WCA measurements of aC etch

• Significant modification of aC @ low plasma temperature (65 ºC), no etch, carbon reduction

• Hight process temperature – aC etch, dangling bonds formation, impurities for the chamber sidewalls

XPS C1s

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ALD Ru at 250 C

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RBS Ru areal density• Clear benefit in ALD inhibition after cold

He/H2 plasma (H radicals only)

• To be tested on a patterned structure

Plasma T ºC decrease

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MD modeling of aC exposed to H ions

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Power,

W

Ne, cm-

3

Vrf Te,

eV

H flux, cm-2s-1 H3+ flux, cm-2s-1 H2

+ flux, cm-2s-

1

H+ flux, cm-

2s-1

150 1.3∙1010 180 2 1.8∙1016 1.5∙1015 3.1∙1014 1.5∙1014

300 2.7∙1010 270 1.6 2.6∙1016 2.5∙1015 5.7∙1014 3.3∙1014

Discharge parameters obtained in PIC MCC simulation- 300 mm CCP plasma reactor

(Particle‐in‐cell with Monte Carlo Collision)

Modeling of

the plasma

discharge

MD

modeling of

aC exposed

to H ions

MD

modeling of

aC exposed

to H radicals

• H radicals are the main species in H2 plasma

• Concentration of H3+ ions is 10 times lower in comparison with the concentration of H radicals

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MD modeling of aC exposed to H ions

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Ion energy distribution function

Mean energy of H ions:

300 W – ion energy of 120 eV

60 W – ion energy of 50 eV

• H radicals energy increases with the plasma power increase

• 300 W – H ion energy of 120 eV

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MD modeling of aC exposed to 120 eV H ions at different ion fluences

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• aC layer thickness increases by 3.2 nm, no etch is observed. Etch requires both: H ions and radicals

• H penetrates into aC film, C-C bonds scission

• Hydrogenation occurs in the bulk of aC

Starting ratio of sp/sp2/sp3 is 4/65/31

H ion fluences

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MD modeling of aC exposed to 120 eV H ions at different ion fluences

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a-C density before and after exposure to

H ions at the fluence of 3.2·1016 cm-2

• Hydrogenation occurs mainly in the bulk of the aC film

• The average density of H-modified a-C layer is ~1.4 g/cm3 (initial a-C density is 2.5 g/cm3)

Relative concentrations of C and H atoms

after exposure to H ions at the fluence of

3.2·1016 cm-2

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MD modeling of aC exposed to 120 eV H ions at different ion fluences

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sp sp2

sp3

• CH/CH2 groups are present in 80/20 proportion

• Most of CHx groups are inside of the film

Distribution of CHx groups

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300 W (120 eV) vs 60 W (50 eV)

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• Plasma power decrease results in lower H ion energy

• Low H ion energy results in surface-confined modifications of aC

H concentration

aC density

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MD modeling of aC exposed to H radicals

Page 18: Area-selective Ru ALD by aC modification using H plasma ...€¦ · PUBLIC Ivan Zyulkova,b, Ekaterina Voroninac,d, Mikhail Krishtaba,b, Dmitry Voloshind, BT Chanb, Yuriy Mankelevichd,

MD modeling of aC exposed to H radicals

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• H radicals do not break C-C bonds, but they break C=C

• Surface hydrogenation and increase sp2 at the expense of sp

Carbon hybridization fractions before and after

exposure to H radicals

Relative concentrations of carbon and hydrogen in a-

C before and after exposure to H radicals

sp

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CONCLUSIONS

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Experiment

• Downstream He/H2 plasma (H radicals) at 65 ºC does not etch aC. H radicals provide surface

hydrogenation and hydrophibisation (WCA = 97º)

• Downstream He/H2 plasma treatment results in more than 500 cycles ALD inhibition (corresponds to ~

5 nm Ru on SiCN)

MD modeling

• H ions break C-C bonds. H ions combined with H radicals are needed to etch aC

• H radicals do not break C-C bonds at room temperature, however the can transform C=C bonds into

C-C bonds forming CHx groups

• Near-room temperature H radicals treatment (remote H2 plasma) is the best treatment for aC to

maximize the number of CHx groups and minimize layer damage

Page 20: Area-selective Ru ALD by aC modification using H plasma ...€¦ · PUBLIC Ivan Zyulkova,b, Ekaterina Voroninac,d, Mikhail Krishtaba,b, Dmitry Voloshind, BT Chanb, Yuriy Mankelevichd,

PUBLIC