Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F ...

JUNE 27 TUESDAY AFTERNOON
WS-18-TuA-INV.8 ADVANCED PROCESS AND EQUIPMENT CONTROL (APC/AEC)
THROUGH FINE GAS ANALYSIS IN VACUUM SYSTEMS FOR SEMICONDUCTOR
MANUFACTURING. Giuseppe FAZIO, ST Microelectronics - Italy
In the Advanced Process and Equipment Control (APC/AEC) the studies and the evaluations related
to new methodologies and new devices are considered key activities.
In vacuum chamber the Optical Emission Spectroscopy (OES) and Residual Gas Analyzer (RGA)
are two instruments consolidated and widely utilized due to their high performance and flexibility.
OES
RGA
OES and RGA applications
Main application
Other application
Process Control
Equipment Control
(i.e., End Point Detection) (i.e., finger print equipment)
Equipment Control
Process Control
(i.e., leak detection)
(i.e., degas step optimization)
Also from APC/AEC point of view these two instruments (OES and RGA) and their various applicable
methodologies (process and equipment control) have to be continuously developed.
Some of our direct experiences concerning these aspects will be showed.
OES example
Optical emission spectroscopy (OES) is widely used to perform in situ characterization and plasma
processing control, as for instance in dry etching end point detection.
In current practice only UV-VIS range is used, which corresponds to electronic transitions of molecular
or atomic levels.
However, when areas to be patterned within the wafer are small, and etching selectivity is not well
known, the OES could not be enough.
To detect the optical end point a new portion of the spectra has been studied (corresponding to molecular
vibrational modes) and its emission enhancement.
RGA example
When the pressure is lower than 10mTorr a miniature array of quadrupole mass spectrometers has
been considered (Micropole sensor).
This sensor has a small size and it is feasible to install it in a small volume, without loosing high performances,
and turns out to be very flexible on applications.
Recently an instrument for advanced diagnostic using the RGA Micropole has been developed.
This instrument allows technicians to control the vacuum chambers in order to have higher accuracy
and faster analysis, requirements more and more important for hi-tech industries like the semiconductor
one.
When the pressure is higher than 10mTorr the traditional RGA (quadrupole) requires pump system.
For this reason the system is not suitable for industrial field: cumbersome and complicated from a
maintenance point of view.
Therefore, we have evaluated alternative instruments: ICP plasma source, analysis by OES of atomic
and molecular emission due to plasma excitation of residual gases.
Hardware malfunctions were simulated on etch equipment and the consequent behaviour of the
plasma emission spectrum was analyzed in order to evaluate and quantify detectable differences.
The installation of this type of sensor on Transfer Module of the metal etch tool has been planned for
the detection in line for leakage and humidity. In particular the focus concerns the wet cleaning recovery
after PM and the reduction of the possible particle contamination produced by humidity.
83