Significant progress has been made with 2 years of research on the formation of shock sensitive silane gels. This will be the second all day seminar on hexachlorodislane. It will cover the lifecycle from supplier to use and equipment. As noted last year, one manufacturer burned down their US facility plus the fatal accident (5 died and 13 injured) in Japan. A number of fires/explosions have occurred during PM. There are some systems that we do not yet know how to remove these safely. In one I shut the site down for a week as we attempted to dissolve the gel. As the small pieces hit the ground they exploded

Reactive HCDS Byproducts

2019 SESHA PDC

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

Eugene Ngai

Chemically Speaking LLC

www.chemicallyspeakingllc.com