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Assessing the need for FC abatement 

standards

Without a script, the semiconductor industry nonetheless appears well along the way toward a 

voluntary goal of the World Semiconductor Council (WSC) to limit atmospheric emissions of 

gaseous fluorinated compounds (FCs). The goal commits members to reduce certain FC 

emissions to 10% below base-year amounts (which vary regionally) by 2010. However, we lack 

an industry standard for defining and measuring destruction or removal efficiency (DRE) of FC 

abatement systems, so the playing field isn’t level, and the veracity of reports and attainability of 

the goal can be questioned.

Atmospheric FCs-specifically CF4, CHF3, C2F6, C3F8, c-C4F8, NF3, and SF6, which may be 

emitted during CVD chamber-clean and etch processes-have high global warming potentials 

(GWPs). Expressed as mass CO2-equivalents, these FCs have GWPs that are more than 3-4 

orders of magnitude higher in trapping the earth’s reradiated heat compared to an equivalent 

amount of CO2.

With the strong growth in semiconductor manufacturing, emission-reducing technologies must 

achieve an average effectiveness of 90% compared to no control. For any particular company, 

the average FC-reduction requirement could be as little as 70% or more than 90% depending on 

growth beyond the base-year. 

Chip manufacturers, according to International SEMATECH’s latest (2005) State-of-theTechnology Report, can use various FC emission-reducing solutions with 10-99% efficiencies. 

While favoring a “pollution prevention” approach that puts process optimization and/or 

alternative gases ahead of abatement, post-process FC-destruction may still be needed according 

to the SEMATECH report. 

However, no industry-standard definition and no standard protocol for the measurement of DRE 

exist. What matters is the amount of atmospheric FC emitted-the total mass CO2-equivalents of 

all relevant FC emissions. Yet, many fab ESH solutions merely lower FC wastes to safe 

concentrations. At issue are the effects of dilution and formation of FCs. Many abatement 
technologies use additives that dilute the exhaust stream. So, defining and measuring DRE as a 

difference between input and output FC-concentrations, without accounting for the influence of 

dilution and the presence of other FCs, will overstate DREs and understate estimates of 

emissions. 

For example, in popular thermal destruction systems, neglecting dilution can result in DREs 

being overstated for CF4 by a factor of 20 to 50. A thermal system’s DRE for abating C2F6 can 

be overstated by a factor of 10 if the effects of both dilution and CF4 formation are neglected. 

We should build on the collaboratively developed, widely used Intel Emissions Protocol 

Revision 2.4b, which guides equipment manufacturers’ quantitative characterization of FC 

emissions. All estimates of FC-process emissions can be traced to this protocol.

Either the Intel protocol should be updated or a new protocol developed to explicitly address 

measuring DREs for all relevant abatement technologies that claim FC-destruction capabilities: 

incineration-type abatement with and without catalytic assistance, heated-tube type abatement 

with and without catalytic assistance, and plasma-type abatement, both low- and high-pressure 

configurations. The new protocol should:

Adopt the definition of DRE included in the just-published IPCC FC emissions inventory 

guidance, which requires measurement of the total mass of all relevant FCs entering and 

leaving the system and so explicitly accounts for the effects of dilution. 

Adopt minimal as well as best-methods for conducting representative sampling and for 

measuring total mass flow of all relevant FC effluents and all F-containing effluents that 

enter and leave the abatement system. 

Provide standards for documenting and reporting. 

Identify the requirements for achieving and maintaining the measured DRE performance 

over an annual period. 

Assure that DREs quoted in purchase agreements are based on the new protocol and that 

the OEM requirements for achieving that DRE performance span an annual period.

The time for completing and implementing the needed DRE-measuring protocol is short. The 

effort will be significant, but the rewards will exceed the costs. Without such a protocol, the 

significant investment to attain the heralded WSC goal is threatened, as is the industry’s even 

larger investment to paint itself green.

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Contact C. (Shep)herd Burton, an independent consultant serving clients in air 

quality management, at e-mail: burtonentp@comcast.net

To access this Article, go to: 

http://www.electroiq.com/content/eiq-2/en/articles/sst/print/volume-50/issue1/departments/industry-forum/assessing-the-need-for-fc-abatement-standards.html