Optimizing implanter vacuum performance with various cassette materials

IC manufacturers will often adopt new cassette materials for particulate control, dimensional stability, and improved thermal properties. In order to maintain tool performance, in some cases the introduction of these new materials introduce new demands on the vacuum system. Six cassette materials have been tested in a medium current implanter using eight pump configurations. The results show that preventing water in the load lock from getting to the process chamber is important to maximize tool throughput. This paper discusses what options are currently available to compensate for new vacuum demands that are related to hygroscopic cassette materials.