Environmental-friendly fluorine mixture for CVD cleaning processes to replace C2F6, CF4 and NF3
The target of this work was to find viable alternative CVD-cleaning gas mixtures for the semiconductor industry, which are environmental-friendly and in addition can be used as a "drop in" to avoid high investment costs from equipment modification. Our study has demonstrated that this can be achieved with F2-based gas mixtures, which also provide a more efficient and faster cleaning behavior for most applications. A cleaning efficiency gain of a factor 1.3 up to 17 can be expected, relative to the F2-amount required for cleaning. This gain in efficiency depends on the cleaning gas to be replaced and on the reactor type. A shorter cleaning time can lead into a higher equipment throughput and more cost effective usage of thin film tools. To generate data on particle and tool attrition, a first "mini marathon" test run has been performed. The test reactor, a 200mm wafer size CVD tool, was equipped with a mass spectrometer to monitor the end point of the chamber cleaning an d to gain an overview of the waste gases going into the abatement system.