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 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.

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 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.

ChemInform Abstract: Ultrathin Silicon Nitride Films Fabricated by Single-Wafer Processing Using an SiH2Cl2-NH3-H2 System and in situ H2 Cleaning.

ChemInform ◽  
2010 ◽  
Vol 27 (33) ◽  
pp. no-no
Author(s):  
K. KOBAYASHI ◽  
Y. INABA ◽  
T. OGATA ◽  
T. KATAYAMA ◽  
H. WATANABE ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Silicon Nitride Films ◽  
Wafer Processing

Correlation Between The Mechanical Stress And Microstructure In Reactive Bias Magnetron Sputtered Silicon Nitride Films

1997 ◽  
Vol 505 ◽  
Author(s):  
Joo Han Kim ◽  
Won Sang Lee ◽  
Ki Woong Chunga
Keyword(s):  
Silicon Nitride ◽  
Mechanical Stress ◽  
Bias Voltage ◽  
Etch Rate ◽  
Rutherford Backscattering Spectrometry ◽  
Substrate Bias ◽  
Substrate Bias Voltage ◽  
Silicon Nitride Films ◽  
Transmission Electron ◽  
Bombardment Energy

ABSTRACTThe influence of ion bombardment on the mechanical stress and microstructure of sputtered silicon nitride (SiNx) films has been systematically investigated. Applied substrate bias voltage was used to control the bombardment energy in a radio frequency (rf) reactive magnetron sputtering system. The resultant films were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), Rutherford backscattering spectrometry (RBS), stress and chemical etch rate measurements. As the bias voltage was increased, the internal stress in SiNx films became increasingly compressive and reached a value of about 18.3 × 109 dyne/cm2 at higher bias voltages. These correlated well with the transition of the film microstructure from a porous microcolumnar structure containing large void to the more densely packed one. The obtained results can be explained in terms of atomic peening by energetic particles, leading to densification of the microstructure. It was also found that the amount of argon incorporated in the film is increased with increasing bias voltage, whereas the oxygen content is decreased. The lowest etch rate in buffered HF solution, approximately 1.2 Å/sec, was observed with the application of a substrate bias of -50 V.

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