May 17, 2012

1

Proposal to Incorporate ISMI 2009 Guideline References in Subpart I

The ISMI environmental characterization guideline was written to encompass the measurements that 

can be used to quantify all environmental impacts of semiconductor process tools, attached peripheral 

equipment and point of use abatement devices. The scope of the guideline goes well beyond addressing 

point of use (POU) abatement testing; therefore, only those sections that apply to POU abatement 

testing should be included in Subpart I. Improvements to the measurement processes have been gained 

through application of the 2009 ISMI guideline methods in operating fabs over the last three years by the 

industry and testing contractors. The language from the 2009 Guideline that SIA proposes for the rule 

follows, with some revisions where needed to reflect increased knowledge. Italics are used to for 

clarifying text.

The EPA DRE protocol currently references the 2006 ISMI guideline and should be revised.

Proposed Text for Inclusion in Subpart I:

Mass Spectrometry testing will be conducted in accordance with provisions of Appendix A.1 in the 2009 

ISMI Environmental Characterization Guideline.

FTIR testing will be conducted in accordance with the provisions of Appendix A.2.

NOTE: Appendix A.2 references in several places the use of a calibration transfer standard (CTS). 

As we read Appendix A.2, it is not required and it is important that, as the Agency incorporates 

Appendix A.2 into the rule, its applicability remains limited. The use of a CTS is necessary, in 

certain instances, to validate optical pathlength for spectrometers where cell optical pathlength 

is variable. For fixed pathlength spectrometers, the use of a CTS standard as described in 

Appendix A.2 is not needed and should not be required.

In addition to the methods listed in the EPA DRE Protocol, the following alternative method (a 

combination of modifications to Appendix B.1.5 and EPA Method 7E) may be used to determine POU 

abatement device outlet total volumetric flow. 

Changes to Appendix B.1.5 and Method 7E include:

 Allowance for introduction of the non-reactive gas between the oxidizer and the scrubber in 

the point of use abatement device. 

 Removed the 8 duct diameter requirement that appears in B.1.5. 

 Removed the allowance that stratification testing is not required for ducts 4” diameter or 

less that appears in Method 7E (because stratification can occur in smaller ducts). 

 Removed the requirement to sample for twice the system response time for each traverse. 

This comes from Method 7E but is not relevant to FTIR.

 The allowed percentage variations in Method 7E have been doubled but the ppmv

alternative criterion has been removed.

 Added a description of the number of measurements and flow rates required for determining 

POU abatement device effluent flow by this method using FTIR.
May 17, 2012

2

Another methodology is to accurately flow a non-reactive gas (e.g., CF4) into the POU abatement device 

outlet, or between the oxidizer and the scrubber, and measure the concentration downstream (usually 

by FTIR). The following criteria must be fulfilled when using this methodology:

1. The POU abatement device outlet must be sampled to ensure that the non-reactive gas 

is not present.

2. The non-reactive gas can be injected across the duct. This can be done using an 

injection probe with equally spaced holes.

3. The location selected for downstream non-reactive gas sampling must also be used for 

POU abatement device outlet sampling. This will ensure that any dilution from POU 

abatement device outlet to this sampling location will be accounted for.

4. The sampling location should be traversed with the sampling probe measuring the nonreactive gas concentrations to ensure homogeneity of the non-reactive gas and POU 

abatement device effluent (i.e. stratification test). To test for stratification, measure the 

non-reactive gas concentrations at three points on a line passing through the centroidal 

area. Space the three points at 16.7, 50.0, and 83.3 percent of the measurement line. 

Calculate the individual point and mean non-reactive gas concentrations. If the nonreactive gas concentration at each traverse point differs from the mean concentration 

for all traverse points by no more than: (a) ± 10.0 percent of the mean concentration, 

the gas stream is considered unstratified and you may collect samples from a single 

point that most closely matches the mean. If the 10.0 percent criterion is not met, but 

the concentration at each traverse point differs from the mean concentration for all 

traverse points by no more than: (a) ± 20.0 percent of the mean, the gas stream is 

considered to be minimally stratified, and you may take samples from three points. 

Space the three points at 16.7, 50.0, and 83.3 percent of the measurement line. If the 

gas stream is found to be stratified because the 20.0 percent criterion for a 3-point test 

is not met, locate traverse points for the test in accordance with Table 1–1 or Table 1–2 

of EPA Method 1.

5. A minimum of 40 non-reactive gas concentration measurements will be collected at 3-5 

different injected non-reactive gas flow rates for determination of POU abatement 

device effluent flow. The total volumetric flow of the POU abatement device exhaust 

will be calculated consistent with the EPA Protocol Equations 1 through 7.