SESHA 2019 Symposium PDC

Reactive Silane Byproducts Phase 2


Chemically Speaking LLC


Since the Reactive Silane Byproducts PDC in April 2018, another year of research has been conducted on this important topic. In one test program, a custom benchscale system was used to simulate a user system and process conditions to better understand how these reactive gels are formed. A key finding is that the reactive gels formed by hydrolysis of hexachlorodisilane is different than hydrolyzed HCDS reactor gels. While both forms can be shock sensitive, they exhibit different chemical and physical properties.

Some of the gels formed are so shock sensitive that a fire occurred when a label was peeled off of a vacuum pump containing gels. A chlorosilane manufacturer reported that a facility bicycle rolled over dried deposits on the ground and reported hearing “popping” sounds. The most likely place for these gels to form are in the reactor system vacuum pumps after the heated foreline. The gels from a number of pumps from 2 US users have been studied. These gels are viscous and waxy like that quickly reacts to a brittle solid after exposure to ambient air.

This PDC will have the same speakers from 2018 plus Global Foundries. Key topics will be
1. Reactive chemical hazard analysis -- mitigation of shock sensitive gels
2. Process vacuum pumps were modified to reduce accumulation of reactive byproducts
and extend pump life. Results of recent pilot tests will be presented.
3. Gel formation in heated foreline and ambient
4. Deposits found in a user’s foreline have also been characterized
5. F2 Cleaning of gel and hydrolyzed gel
6. Neutralization of hydrolyzed HCDS spill
7. User experience
8. Methods of in situ deactivation of hydrolyzed gels (chemical, heat, steam)
9. Chemical scrubbing of HCDS vapors
Speakers from
1. National Kaohsiung University of Science and Technology
2. Dow Chemical
3. Global Foundries
4. Edwards Vacuum
5. Dekra
6. Chemically Speaking LLC

This PDC will present data that has not been revealed and may be significant to your operations.