Elsevier

Current Applied Physics

Volume 18, Issue 11, November 2018, Pages 1436-1440
Current Applied Physics

Study on SiN and SiCN film production using PE-ALD process with high-density multi-ICP source at low temperature

https://doi.org/10.1016/j.cap.2018.08.012Get rights and content

Abstract

SiN and SiCN film production using plasma-enhanced atomic layer deposition (PE-ALD) is investigated in this study. A developed high-power and high-density multiple inductively coupled plasma (multi-ICP) source is used for a low temperature PE-ALD process. High plasma density and good uniformity are obtained by high power N2 plasma discharge. Silicon nitride films are deposited on a 300-mm wafer using the PE-ALD method at low temperature. To analyze the quality of the SiN and SiCN films, the wet etch rate, refractive index, and growth rate of the thin films are measured. Experiments are performed by changing the applied power and the process temperature (300–500 °C).

Introduction

Atomic layer deposition (ALD) has been a well-known method for obtaining a thin film by stacking a very thin layer on a substrate. This process has been becoming a main processing in the semiconductor fabrication process. Plasma sources, such as capacitively coupled plasma (CCP), inductively coupled plasma (ICP), and microwave plasma (MW), have been widely used for ALD processes in the semiconductor, flat-panel display, and solar-cell industries. Additionally, a few studies have been reported to develop the semiconductor fabrication process with high-density plasma sources, such as helicon plasma [[1], [2], [3], [4]] and electron cyclotron resonance (ECR) plasma [5,6].

Recently, plasma-enhanced (PE) ALD process—an ALD process with a plasma source—have been widely studied [[7], [8], [9]]. In addition, high-density nitride thin film deposition processes have been increasing in the semiconductor fabrication process.

Since the semiconductor process of 10–20 nm class has been widely applied [10,11], the need for developing micro-processing has been increased due to small gate-line width and high aspect ratio. ALD of SiNx thin film has been performed at a high temperature (approximately 600 °C). However, the high temperature process has caused performance degradation problem of the semiconductor device. Consequently, a low-temperature ALD process technology has been required [[12], [13], [14], [15], [16]]. Some studies have been reported to deposit high-quality SiN films using a PE-ALD process below 200 °C using microwave electron cyclotron resonance (M-ECR) plasma sources [[17], [18], [19]].

In this paper, low temperature PE-ALD processing with a developed high power (∼10 kW) multi-ICP source is studied. The plasma source is used for the PE-ALD process to produce SiN and SiCN thin films at low temperature (300–550 °C). Uniform plasma discharge is generated by the plasma source. Also, high-density plasma discharge is generated since high power is applied. After the PE-ALD process, we analyze characteristics (wet etch rate, refractive index, and growth rate) of the deposited SiN and SiCN thin films using secondary-ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS) analysis [[20], [21], [22], [23], [24]].

Section snippets

Experimental setup

To carry out the PE-ALD process, the multi-ICP, in which seven coils are connected in parallel, is developed and used in the experiment. A 2D probe system is designed and constructed for the electron density measurement and plasma uniformity measurement. SIMS and XPS analysis are constructed to analyze film characteristics after the PE-ALD process.

Fig. 1 shows the high-power multi-ICP source setup. It generates N radicals inside the chamber during the PE-ALD process. The discharge tube is

N2 plasma discharge

N2 plasma discharge experiments are performed before conducting the PE-ALD process. 112 sccm of N2 gas (16 sccm flow to the discharge tube at the center, and 96 sccm flow to the other six tubes at the edge) is injected to the chamber. The pressure in the chamber is 10 mTorr. Only N2 gas is used. The power applied to edge ICP antennas and the center antenna is 9 kW and 1 kW, respectively with the RF frequency of 13.56 MHz.

Ion saturation current measurement using 2D probe

Improving uniformity is an important issue in the development of multiple

N2 plasma discharge with the high power multi-ICP source

N2 plasma discharge is produced using a high-power multi-ICP source. Fig. 3 shows the change in the electron density in the plasma changes when the applied RF power changes. It is measured using a single Langmuir probe 125 mm below the discharge tube. The electron density increases as the applied RF power increases. The higher the electron density in the N2 plasma, the higher the N radical formation rate. This can directly improve the gate-oxide nitridation and gate-sidewall-spacer nitridation

Conclusions

In this study, a new type of multi-ICP source (seven-coil) is developed that can apply high power (∼10 kW) to generate high-density N2 plasma and then apply it to the ALD process at a low temperature (300–550 °C). A high-density plasma environment with a high electron density and uniformity (<4.0%) can be achieved by inducing the N2 plasma discharge by applying high power to seven antennas in parallel. The electron density and uniformity of the plasma density can be calculated by measuring the

Acknowledgements

This research was supported by the MOTIE(Ministry of Trade, Industry & Energy) (10049065) and KSRC(Korea Semiconductor Research Consortium) support program for the development of future semiconductor device.

References (33)

  • F.F. Chen et al.

    IEEE Trans. Plasma Sci.

    (1997)
  • W.T. Li et al.

    Electron. Lett.

    (2007)
  • B. Diaz et al.

    Corrosion Sci.

    (2011)
  • L.G. Gosset et al.

    J. Non-Cryst. Solids

    (2002)
  • R.W. Boswell et al.

    IEEE Trans. Plasma Sci.

    (1997)
  • T.P. Schneider et al.

    Plasma Sources Sci. Technol.

    (1999)
  • J. Asmussen

    J. Vac. Sci. Technol. A

    (1989)
  • S. Nakayama

    Pure Appl. Chem.

    (1990)
  • S.X. Lao et al.

    J. Vac. Sci. Technol. A

    (2005)
  • A. Perros et al.

    J. Vac. Sci. Technol. A

    (2011)
  • S. Weeks et al.

    J. Vac. Sci. Technol. A

    (2015)
  • K. Schuegraf et al.

    IEEE J. Electron Devices

    (2013)
  • M. Ieong et al.

    Science

    (2004)
  • P.A. Keiter et al.

    Phys. Plasmas

    (1997)
  • S.V. Nguyen

    IBM J. Res. Dev.

    (1999)
  • S.W. King

    J. Vac. Sci. Technol. A

    (2011)
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