In-Situ Spectroscopic Ellipsometry and Optical Emission Studies of CF4/O2 Plasma Etching of Silicon Nitride

1999 ◽  
Vol 569 ◽  
Author(s):  
T. Parent ◽  
J. Tie ◽  
A. Madhukar
Keyword(s):  
Silicon Nitride ◽  
Real Time ◽  
Plasma Etching ◽  
Spectroscopic Ellipsometry ◽  
Etch Rate ◽  
Electron Cyclotron Resonance ◽  
Optical Emission ◽  
Sample Introduction ◽  
Chamber Pressure

ABSTRACTElectron cyclotron resonance (ECR) CF4/ 02 plasma etching of silicon nitride (SixNy) deposited by plasma enhanced chemical vapor deposition (PECVD) has been examined in-situ by means of spectroscopic ellipsometry (SE) and optical emission (OE). The observed real-time etchrate and the relative intensity of emission of atomic fluorine at 703.7 nm are measured simultaneously and both are found to change with time during the etch in a reproducible manner. The evolution of the real-time etch rate and the fluorine emission intensity depends on the machine input settings and the extent to which the chamber has been exposed to CF4/ 02 plasma prior to sample introduction. In general the initial 10 to 40 seconds of etching reveal a rapid increase in the etch rate, the remainder of the etch exhibiting an etch rate which typically increases gradually until the etch is stopped. This variation in etch behavior with time during the etch process complicates the task of precisely and reliably etching ultrathin (< 50 nm) films, necessitating real-time control based upon in-situ sensors, the end objective of this work. The dependence of the evolution of the SixNy etch rate on microwave power, chamber pressure, and gas in-flow rate is presented and the implications of these dependencies on the implementation of real-time feedback control are discussed.

In Situ Spectroscopic Ellipsometry for the Real Time Process Control of Plasma Etching of Silicon Nitride

1999 ◽  
Vol 591 ◽  
Author(s):  
I. G. Rosen ◽  
T. Parent ◽  
B. Fidan ◽  
A. Madhukar
Keyword(s):  
Silicon Nitride ◽  
Real Time ◽  
Plasma Etching ◽  
Spectroscopic Ellipsometry ◽  
Etch Rate ◽  
Polarization State ◽  
Non Invasive ◽  
Silicon Nitride Films ◽  
In Situ Sensor

ABSTRACTSpectroscopic ellipsometry (SE) is a commonly used non-destructive, non-invasive in-situ sensor for dry etching. SE measures the change in the polarization state of light reflected from a surface. Sample thickness is obtained by fitting a model to the experimental ellipsometry data. In this paper we describe the design, testing and evaluation of an SE based adaptive real time feedback controller for etch rate regulation in CF4/O2 plasma etching of silicon nitride films. The feedback variable is the current etch rate as determined from the in-situ SE measurements of the film's thickness. The controller compensates for drifts in etch rate which occur during a given etch, and adaptively adjusts for the run-to-run variability inherent to plasma processing. Experimental results are presented and discussed.

In Situ Studies of Electron Cyclotron Resonance Plasma Etching of Semiconductors by Spectroscopic Ellipsometry

1992 ◽  
Vol 279 ◽  
Author(s):  
S. Nafis ◽  
N. J. Ianno ◽  
Paul G. Snyder ◽  
John A. Woollam ◽  
Blame Johs
Keyword(s):  
Real Time ◽  
Plasma Etching ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Electron Cyclotron ◽  
Bulk Silicon ◽  
Bulk Materials ◽  
Insight Into ◽  
Resonance Plasma

ABSTRACTIn situ ellipsometry at selected wavelengths in the spectral range 280 nm to 1000 nnn was performed during the rf bias assisted electron cyclotron resonance (ECR) etching of bulk silicon, GaAs, InP, and GaAs/AlGaAs/GaAs, and InGaAs/InP layered strcutures by a CCl2F2 based etch gas.While real time thickness changes for bulk materials cannot be determined ellipsometrically, some insight into the etch mechanism may be gained by observing the effect of the process on the surface dynamically, and after the etch process has been completed. Monitoring of the layered structures during etching can provide a real time measure of the amount of material remaining in the layer being etched, and provide tight process control.

Real-Time Feedback Control of Thermal CL2 Etching of GaAs Based on In-Situ Spectroscopic Ellipsometry

1997 ◽  
Vol 502 ◽  
Author(s):  
T. Parent ◽  
R. Heitz ◽  
P. Chen ◽  
A. Madhukar
Keyword(s):  
Real Time ◽  
Spectroscopic Ellipsometry ◽  
Etch Rate ◽  
Control Algorithm ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Square Root ◽  
Arrhenius Dependence ◽  
Etching System

ABSTRACTIn-situ, real-time, spectroscopic ellipsometry (SE) is utilized to study thermal chlorine etching of GaAs in an all ultra-high-vacuum interconnected growth and etching system. In the low temperature (between ˜40°C and ˜120°C) range, the etch rate is found to exhibit an Arrhenius dependence on substrate temperature with an activation energy of 11.6Kcal/mole and to be proportional to essentially the square root of the chlorine pressure. An SE feedback based real-time etch process control algorithm is developed and successfully implemented on the basis of the above noted input - output relation derived from the experimental data base.

In-Situ Fiberoptic Thermometry Measurements Of Wafer Temperature During Plasma Etching Using An Electron Cyclotron Resonance Source

1995 ◽  
Vol 406 ◽  
Author(s):  
S. Thomas ◽  
E. W. Berg ◽  
S. W. Pang
Keyword(s):  
Microwave Power ◽  
Cyclotron Resonance ◽  
Etch Rate ◽  
Electron Cyclotron Resonance ◽  
Plasma Heating ◽  
Electron Cyclotron ◽  
Chamber Pressure ◽  
Rf Power ◽  
Wafer Temperature

AbstractThe increase in wafer temperature due to plasma heating during etching has been studied. Si and InP were etched using a high ion density discharge generated by an electron cyclotron resonance source. The wafer temperature was measured in-situ using fiberoptic thermometry as microwave power, rf power, chamber pressure, and gas flow were varied. Wafer temperatures increased with both microwave and rf power, and decreased with chamber pressure. For rf power of 50 W, chamber pressure of 1 mTorr, a source distance of 13 cm, and 10 sccm Ar flow, an increase in microwave power from 50 to 500 W caused the temperature to increase from 62 to 186 °C. Additionally, the use of He flowing at the backside of the wafer for temperature control was analyzed. By setting the backside He pressure at 3 Torr, the temperature increased from 20 °C at the beginning of the etch to only 29 °C after 12 min. Time dependent etch characteristics of InP were studied and related to the wafer temperature measurements. At 100 W microwave power, the InP etch rate increased from 100 to 400 nm/min as the wafer temperature rose from 20 to 150 °C. As the temperature increased above 150 °C, the profile became more undercut and the surface morphology improved. By setting the stage temperature to -100 °C and using 3 Torr He pressure at the backside of the wafer, the InP etch rate remained constant during etching and undercutting was suppressed. For 500 W microwave power, a fast InP etch rate of 2 μm/min was obtained when the wafer temperature was <110 °C, and it increased to over 4 μm/min when the temperature was >150 °C.

scholarly journals Machine Learning Prediction of Electron Density and Temperature from Optical Emission Spectroscopy in Nitrogen Plasma

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1221
Author(s):  
Jun-Hyoung Park ◽  
Ji-Ho Cho ◽  
Jung-Sik Yoon ◽  
Jung-Ho Song
Keyword(s):  
Machine Learning ◽  
Electron Temperature ◽  
Real Time ◽  
Electron Density ◽  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Plasma Nitridation

We present a non-invasive approach for monitoring plasma parameters such as the electron temperature and density inside a radio-frequency (RF) plasma nitridation device using optical emission spectroscopy (OES) in conjunction with multivariate data analysis. Instead of relying on a theoretical model of the plasma emission to extract plasma parameters from the OES, an empirical correlation was established on the basis of simultaneous OES and other diagnostics. Additionally, we developed a machine learning (ML)-based virtual metrology model for real-time Te and ne monitoring in plasma nitridation processes using an in situ OES sensor. The results showed that the prediction accuracy of electron density was 97% and that of electron temperature was 90%. This method is especially useful in plasma processing because it provides in-situ and real-time analysis without disturbing the plasma or interfering with the process.

In Situ Study of Barrier Layers Using Spectroscopic Ellipsometry and Mass Spectroscopy of Recoiled Ions

2000 ◽  
Vol 619 ◽  
Author(s):  
Y. Gao ◽  
A.H. Mueller ◽  
E.A. Irene ◽  
O. Auciello ◽  
A.R. Krauss ◽  
...  
Keyword(s):  
Real Time ◽  
Mass Spectroscopy ◽  
Spectroscopic Ellipsometry ◽  
Nitrogen Concentration ◽  
Random Access ◽  
Copper Interconnects ◽  
Access Memory ◽  
Barrier Layers ◽  
The Stability

ABSTRACTAn in situ study of barrier layers using spectroscopic ellipsometry (SE) and Time-of-Flight (ToF) mass spectroscopy of recoiled ions (MSRI) is presented. First the formation of copper silicides has been observed by real-time SE and in situ MSRI in annealed Cu/Si samples. Second TaSiN films as barrier layers for copper interconnects were investigated. Failure of the TaSiN layers in Cu/TaSiN/Si samples was detected by real-time SE during annealing and confirmed by in situ MSRI. The effect of nitrogen concentration on TaSiN film performance as a barrier was also examined. The stability of both TiN and TaSiN films as barriers for electrodes for dynamic random access memory (DRAM) devices has been studied. It is shown that a combination of in situ SE and MSRI can be used to monitor the evolution of barrier layers and detect the failure of barriers in real-time.

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