Reduction of Perfluorocompound (PFC) Emissions: 2005 State-ofthe-Technology Report 

International SEMATECH Manufacturing Initiative 

Technology Transfer #05104693A-ENG 
© 2005 International SEMATECH Manufacturing Initiative, Inc. 

SEMATECH and the SEMATECH logo are registered service marks of SEMATECH, Inc. 

International SEMATECH Manufacturing Initiative and the International SEMATECH Manufacturing 

Initiative logo are registered service marks of International SEMATECH Manufacturing Initiative, Inc., a whollyowned subsidiary of SEMATECH, Inc. 

Product names and company names used in this publication are for identification purposes only and may be 

trademarks or service marks of their respective companies. 
Reduction of Perfluorocompound (PFC) Emissions: 2005 State-of-theTechnology Report 

Technology Transfer #05104693A-ENG 

International SEMATECH Manufacturing Initiative 

December 2, 2005 

Abstract:

technology development and implementation and describes the semiconductor industry’s efforts to 

reduction processes and technology obtained from a survey of members of the International 

SEMATECH Manufacturing Initiative (ISMI); the Semiconductor Industry Association (SIA); the 

World Semiconductor Council (WSC); and chemical, tool, and abatement device suppliers. The 

appendix includes details about process optimizations, alternative processes, and abatement 

technologies. 

Keywords: Emissions Reduction, Perfluorocompounds, Pollution Control Equipment, Global Climate 

Change, Chamber Cleaning, Process Optimization

Authors: Laurie S. Beu Consulting, Austin, TX 

Approvals: Walter Worth, Project Manager 

Ron Remke, Program Manager 

Scott Kramer, Director 

Laurie Modrey, Technology Transfer Team Leader 

reduce PFC emissions. It documents pre-competitive information about potential PFC emission 

This report from the ESHI002M project reviews the current state perfluorocompound (PFC) 

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ISMI Technology Transfer #05104693A-ENG 

Table of Contents 

1 EXECUTIVE SUMMARY .....................................................................................................1

2 INTRODUCTION...................................................................................................................2

3 BACKGROUND.....................................................................................................................2

4 EMISSIONS REDUCTION TECHNOLOGY DEVELOPMENT .........................................3

4.1 Process Optimization/Alternative Processing.................................................................3 

4.2 Alternative Processing: Remote Clean ...........................................................................4 

4.3 Remote Clean Byproduct ESH Concerns .......................................................................4 

4.4 Alternative Chemistry .....................................................................................................5

4.4.1 Chamber Clean: ≤150 mm and Older 200 mm Process Tools............................5 

4.4.2 Chamber Clean: Advanced 200 mm and 300 mm ..............................................6 

4.4.3 Chamber Clean: Research and Development......................................................6 

4.4.4 Plasma Etch.........................................................................................................7 

4.5 Capture/Recovery............................................................................................................7 

4.6 Abatement .......................................................................................................................8 

5 INDUSTRY APPLICATION OF EMISSION REDUCTION OPTIONS...............................9

6 IMPACT OF INDUSTRY CHANGES ON EMISSIONS.....................................................10

6.1 Chamber Cleans ............................................................................................................10 

6.2 Etch ...............................................................................................................................11 

6.3 Future Technologies That May Impact PFC Emissions ...............................................11 

6.4 Changes in Wafer Size..................................................................................................12 

7 SIA PROGRESS TOWARDS 10% EMISSIONS REDUCTION GOAL.............................14

8 PROJECTED WSC EMISSIONS .........................................................................................14

9 DISCUSSION AND ANALYSIS..........................................................................................15

9.1 Applicability of Technologies.......................................................................................15 

9.2 Process Optimization/Alternative Processing...............................................................16 

9.3 Alternative Chemistries.................................................................................................16 

9.4 Capture/Recovery..........................................................................................................16 

9.5 Abatement .....................................................................................................................16 

9.6 Impact of New Process Technology .............................................................................17 

10 CONCLUSIONS ...................................................................................................................18

11 REFERENCES......................................................................................................................18

APPENDIX A – Process Optimization/Alternative Processing.....................................................21

A.1 Process Optimization ....................................................................................................21 

A.2 Endpoint Detection........................................................................................................22 

A.3 Remote Plasma Cleans..................................................................................................23 

A.4 Alternative Chemistry ...................................................................................................25 

A.4.1 Chamber Clean Alternatives .............................................................................26 

A.4.2 Alternative Etch Chemistries ............................................................................34 

A.5 Capture/Recovery..........................................................................................................36 

A.5.1 Air Liquide PFC Capture and Recycle..............................................................36 

A.6 Abatement .....................................................................................................................36 

A.6.1 PFC Abatement – POU Fueled Burner – Scrubber Units.................................36 
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A.6.2 PFC Abatement – POU Catalytic–Scrubber Units............................................48 

A.6.3 PFC Abatement – POU Electrically Heated Thermal – Scrubber Units...........54 

A.6.4 PFC Abatement – POU Atmospheric Plasma Units .........................................59 

A.6.5 PFC Abatement – POU Foreline Plasma Units ................................................65 

A.6.6 PFC Abatement – Centralized Atmospheric Plasma Unit ................................69 

List of Figures 

Figure 1 Wafer Demand Over Time (1995–2010)..................................................................13 

Figure 2 WSC Production Normalized PFC Emissions Over Time .......................................13 

Figure 3 Annual SIA PFC Partner Emissions.........................................................................14 

Figure 4 WSC Indexed PFC Emissions – Actual and Projected ............................................15 

List of Tables 

Table 1 Implemented Alternative Chamber Clean Chemistries..............................................5 

Table 2 PFC Abatement Technologies ....................................................................................8 

Table 3 PFC Emissions Reduction Options ............................................................................9 
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Acknowledgments 

The author would like to thank and acknowledge the following for their contributions: 

Olivier Letessier (Air Liquide) 

Robert Ridgeway and Peter Maroulis (Air Products & Chemicals, Inc.) 

Reed Content, Calvin Gabriel and Arturo Ruiz (Advanced Micro Devices) 

Joseph Van Gompel (BOC Edwards) 

Volker Kinzig (Centrotherm Clean Solutions GmbH) 

A. Frenzel and Jim Hughins (DAS GmbH Dresden) 

Art Liu (Desiccant Technology Corp.) 

Gary Loh and Michael Mocella (DuPont) 

Laura Mendicino, Terry Sparks and Victor Vartanian (Freescale Semiconductor) 

Robert Parkhurst and Bronwyn Pierce (Hewlett Packard) 

Seung-Jong Ko (Hynix Semiconductor Co.) 

Tatsuro Beppu (Kanken Techno Co., Ltd.) 

Linda Gee (LSI Logic) 

Chris Lewis (LegacyTek LLC) 

Rafael Reif and Ajay Somani (Massachusetts Institute of Technology) 

Sebastien Raoux (Metron/Ecosys) 

Michelle Atkinson (Micron Technology, Inc.) 

Richard Banks (National Semiconductor) 

Gabriele Fetzer, Joachim Stache, Harry Thewissen, and Ton van de Kerkhof (Philips 

Semiconductors) 

Wang-Keun Kim (Samsung Electronics) 

Ricky McGowan, Marilyn Redmond, Robert Ruliffson, Susan Vitkavage, and Walter Worth 

(SEMATECH) 

Francesca Illuzzi (ST Microelectronics) 

Bill Delaney and Cher Liu (TecHarmonic) 

J.P. Suplita, Tina Gilliland, and Tim Yeakley (Texas Instruments, Inc.) 

Members of the World Semiconductor Council member associations including: 

EECA/ESIA – Shane Harte and Francesca Illuzzi 

JEITA/JSIA – Takayuki Ohgoshi 

KSIA – Ho-Song Hwang 

SIA – Chuck Fraust 

Members of the ISMI ESH PAG 

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ISMI Technology Transfer #05104693A-ENG 

1 EXECUTIVE SUMMARY 

This report describes the semiconductor industry’s efforts to reduce perfluorocompound (PFC) 

emissions, reviewing the current state of PFC technology development and implementation. It 

documents pre-competitive information about potential PFC emission reduction processes and 

technology obtained through a survey of members of the International SEMATECH 

Manufacturing Initiative (ISMI); the Semiconductor Industry Association (SIA); the World 

Semiconductor Council (WSC); and chemical, tool, and abatement device suppliers. The 

appendix includes details about process optimizations, alternative processes, and abatement 

technologies. 

The industry is steadily decommissioning ≤150 mm fabs, eliminating them as a source of PFC 

emissions. For the majority of operating ≤150 mm fabs, process optimization and drop-in 

alternative chemistries for chemical vapor deposition (CVD) cleans may be the only alternatives 

for reducing emissions, although a few ≤150 mm fabs have installed abatement on certain CVD 

processes. The 200 mm fabs can be divided into two distinct categories: older fabs with an 

installed base of CVD tools using perfluorocarbon clean chemistries and advanced fabs with 

lower emission NF3-based cleans. In older 200 mm fabs, process optimization, installation of 

endpoint detection, installation of remote NF3 cleans, and use of alternative clean chemistries are 

the most prevalent means of reducing emissions. Abatement is also being employed in some 

older 200 mm fabs. The industry and its suppliers have integrated low emission CVD tools into 

advanced 200 mm and 300 mm fabs. Several companies report using abatement technologies to 

reduce etch emissions in their advanced 200 mm and 300 mm fabs, and one company is using a 

central end-of-pipe (EOP) plasma unit to abate CVD emissions from an advanced 200 mm fab. 

Capture/recovery may be appropriate for specialized high volume PFC applications. 

The industry has undergone significant changes that impact PFC emissions. These changes 

include development and implementation of new chamber clean processes and chemistries, 

increased use of plasma etching and adoption of new etch gases, development of new materials 

and processes, and the use of larger wafers to manufacture advanced semiconductor devices. The 

change with the greatest impact on PFC emissions over time is increasing wafer size and the 

corresponding advanced processing technologies. As advanced 200 mm and 300 mm wafer fabs 

began ramping in 2001–2004, the normalized rate of emissions (PFC emitted/cm2

) decreased, 

most likely due to the use of NF3-based chamber clean processes. Based on the changes brought 

about by shifting wafer sizes and the projected acceleration in the transition from old technology 

to new, there is strong reason to believe the normalized rate of PFC emissions will continue to 

decline through 2010: 

• The world semiconductor industry has demonstrated significant commitment to 

reducing PFC emissions. 

• The U.S. semiconductor industry achieved the 10% reduction goal in 2003 and 

surpassed the goal in 2004, despite a significant increase in wafer demand over time. 

• If the current normalized PFC emissions trend continues and wafer demand projections 

are accurate, the world-wide industry will achieve the 2010 goal; however, these trends 

and projections largely depend on the ramping up of lower emitting advanced 200 mm 

and 300 mm fabs and a decrease in the emissions from older, higher emitting fabs. 
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2 INTRODUCTION 

As required by the SIA’s memorandum of understanding with the Environmental Protection 

Agency (EPA), this report describes the semiconductor industry’s efforts to reduce PFC 

emissions. It describes the current state of PFC technology development and the way the industry 

is implementing that technology. It reviews the impact of industry changes on historical and 

projected future emissions and SIA progress towards reducing PFC emissions. Finally, it projects 

future WSC emissions through 2010. This report is a follow-up to Current State of Technology: 

Perfluorocompound (PFC) Emissions Reduction [1], published in 1998. 

3 BACKGROUND 

It has been reported that PFCs have been identified as the most potent greenhouse gases 

measured due to their strong infrared absorption capacity [2]. PFCs are used in semiconductor 

manufacturing for plasma cleaning of CVD chambers and for plasma etching. Examples include 

tetrafluoromethane (CF4), hexafluoroethane (C2F6), octofluoropropane (C3F8), 

octofluorocyclobutane (c-C4F8), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), and 

hydrofluorcarbons (HFCs) such as trifluoromethane (CHF3). It has been reported that PFCs and 

the HFCs are referred to collectively by the industry as PFCs. Additionally, PFCs such as CF4, 

C2F6, c-C4F8, and SF6 persist in the atmosphere for thousands to tens of thousands of years [1], 

making any releases permanent on a human timescale (on the geologic timescale, human 

civilization emerged in the Holocene period covering the past 10,000 years to the present). 

PFCs have been used in semiconductor fabrication facilities (fabs) because they provide uniquely 

effective process performance when etching high aspect ratio features and are a safer, reliable 

source of the fluorine needed for cleaning certain deposition process chambers. 

In 1999, the WSC—whose members at the time were the European Electronic Components 

Manufacturer Association (now the European Semiconductor Industry Association [ESIA]), the 

Electronic Industries Association of Japan (now part of the Japan Electronics and Information 

Technology Industries Association [JEITA], as the Japanese Semiconductor Industry Association 

[JSIA]), the Korean Semiconductor Industry Association (KSIA), and the SIA—approved a 

consensus PFC emissions reduction goal [3]. That goal calls on WSC member associations to 

reduce aggregate absolute emissions of PFCs from semiconductor manufacturing facilities by 

10% or greater from baseline levels by 2010. The baseline year for the ESIA, JEITA-JSIA, and 

SIA is 1995 while the KSIA baseline is 1997. The Taiwan Semiconductor Industry Association 

(TSIA) subsequently joined the WSC, which defined the baseline year for TSIA as the average 

of 1997 and 1999 emissions. It should be noted that the semiconductor industry, through the 

WSC, was the first industry to coordinate globally and voluntarily establish a greenhouse gas 

emissions reduction goal; moreover, the 10% goal exceeds the targets established by the Kyoto 

Protocol for any of the Annex I countries subject to specific greenhouse gas emissions reduction 

targets. 

Concurrent with the establishment of the WSC goal, the U.S. semiconductor industry negotiated 

a second voluntary agreement with the EPA. The PFC Reduction/Climate Partnership 

Memorandum of Understanding (MOU) applies to U.S. semiconductor manufacturing operations 

only and supports the WSC agreement for a collective 10% reduction in emissions by 2010 [4]. 
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Both the WSC consensus paper and the EPA memorandum of understanding call on 

semiconductor manufacturers to share pre-competitive information about potential PFC emission 

reduction processes and technology. The memorandum of understanding has an additional 

requirement that WSC partners publish a progress report by December 15, 2005, detailing 

progress towards achieving the 10% reduction goal. 

This report documents pre-competitive information about potential PFC emissions reduction 

processes and technology obtained from ISMI, SIA, and WSC members. Additionally, 

information was gathered by written surveys of semiconductor manufacturers and suppliers as 

well as a review of relevant literature. Survey responses were received from 18 semiconductor 

manufacturers in the U.S., Europe, and Korea and from 14 suppliers based in the U.S., Europe, 

Japan, and Taiwan. Four WSC trade associations provided specific data while information for 

the fifth association was gathered from the 2005 International Semiconductor Environment, 

Safety, and Health (ISESH) conference proceedings. Emissions projections were developed 

based on VLSI Research, Inc. wafer demand historical data and projections through 2010. 

Normalized PFC emissions rates were calculated based on wafer demand data from Sage 

Concepts for Korea and Taiwan, and Dataquest for the U.S., Europe, and Japan. 

This report reflects information available through July 2005. It is not intended to be a 

comprehensive summary of all PFC emission reduction activities. While attempts were made to 

include developments that occurred or were commercialized after the 1998 report, technologies 

may not be included if the users or developers did not disclose information for competitive or 

other reasons. 

4 EMISSIONS REDUCTION TECHNOLOGY DEVELOPMENT 

The semiconductor industry continues to employ a hierarchy in development of PFC emission 

reduction technology structured around the pollution prevention concepts of reduction, 

replacement, re-use/recycle, and abatement. These development areas are as follows: 

1. Process optimization/alternative processing—reduces the amount of PFCs that are used 

and emitted 

2. Alternative chemistries—reduces or eliminates emissions 

3. Capture/recovery—re-uses or recycles PFCs 

4. Abatement—destroys, reduces, or eliminates PFC emissions so they are not emitted 

Certain technologies that were in research and development stages when ref. [1] was published 

have since been widely implemented by the industry; some technologies have been rejected 

because of poor performance or other issues; and new technologies are being developed and 

evaluated. 

4.1 Process Optimization/Alternative Processing 

Process optimization continues to focus primarily on CVD chamber cleans because they are 

historically the greatest source of PFC emissions; furthermore, they occur in the absence of 

wafers and can be optimized without negatively affecting product yield [4]. Cleans optimization 

can also be applied to etch and other process chambers where PFCs are used for in situ dry 

cleans. The PFC gases used in CVD chamber cleans include C2F6 and CF4 in older (pre-1999) 

manufacturing equipment as well as C3F8, C4F8, octafluorotetrahydrofuran (C4F8O), and NF3 that 
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are lower emitting C2F6 replacement chemistries. Based on 2004 emissions, C2F6 continues to be 

the primary chamber clean gas and currently makes up the majority of semiconductor PFC 

emissions. However, in terms of amounts purchased, NF3 is fast catching up to C2F6. In process 

optimization, endpoint detection or extractive metrology is used to monitor emissions and 

provide clean endpoint times that are minimized by adjusting process parameters such as 

chamber pressure, temperature, plasma power, cleaning gas flow rates, and gas ratios of 

mixtures. Cleans are optimized to minimize gas consumption, thereby lowering the cost of 

ownership (COO) due to decreased gas usage. Process optimization can yield emissions 

reductions of 10–56% compared to baseline C2F6 processes [5] with a potential benefit in 

throughput. Because of industry growth, optimization by itself has not achieved the levels of 

emission reduction the industry needs to meet the 10% goal; however, optimization can reduce 

emissions in older fabs and ensure that new chamber clean processes minimize gas consumption 

and operate efficiently. 

4.2 Alternative Processing: Remote Clean 

Alternative processing—replacing the original process with a new, lower emitting process—has 

undergone significant development in the last decade. The industry has developed remote plasma 

clean technologies to replace in situ C2F6 chamber cleans and CF4 used in nitride chamber clean. 

Remote cleans dissociate NF3 into fluorine ions (F+

) or atoms in a remote plasma and then feed 

the F+ ions/atoms into the process chamber to remove silicon-based residues. Remote cleans 

convert NF3 at 95–99% utilization efficiency [6]. Applied Materials has adopted remote plasma 

technology for chamber cleans across their advanced 200 mm and 300 mm CVD equipment line. 

Other companies have developed remote plasma technologies using NF3 or other PFC 

chemistries that can be retrofitted to certain older CVD chambers. When compared to the 

original carbon-based PFC chamber cleans that they replace, retrofitted remote cleans result in 

>95% PFC emissions reduction [7]. Remote cleans also improve tool utilization by reducing 

clean times and wet clean frequency, improving mean time between failures (MTBF), and 

reducing costs of chamber parts. Additionally, they may improve yield through fewer defects. 

4.3 Remote Clean Byproduct ESH Concerns 

Implementing NF3 remote cleans generates more fluorine (F2) and hydrogen fluoride (HF) 

emissions than fluorocarbon-based cleans [8] and may require additional treatment to remove 

these gases from the exhaust stream, depending on the fab. Fabs typically treat F2 and HF 

exhaust streams with water scrubbers; the additional loading on central end-of-pipe (EOP) 

scrubbers may require modifications to the scrubber systems or installation of point-of-use 

(POU) scrubbers. Depending on a fab’s wastewater discharge limits, scrubber effluent may 

require treatment to decrease the fluoride loading. As noted by Vartanian et al., 

The existing wastewater and/or air pollution control approach and infrastructure may 

not be well suited to the increased F2 load from NF3-based chamber cleans. Thorough 

evaluation of the site's air pollution control strategy, existing wastewater 

handling/treatment infrastructure and capacity, and F2 discharge limits should be 

completed before proliferation of NF3-based chamber cleans [9].

Semiconductor manufacturer surveys indicate that other fabs have responded to similar 

challenges with remote NF3 and the F2. Many fabs have existing fluoride waste treatment 

facilities that remove fluoride by precipitation with some form of calcium, generating calcium 
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fluoride. Because of the significant reduction in PFC emissions and the process benefits, remote 

cleans are a key aspect of the industry’s efforts to reduce PFC emissions; however, 

semiconductor manufacturers should take into account increased F2 and HF loadings when 

developing air and wastewater treatment strategies. 

4.4 Alternative Chemistry 

Significant development has been made in alternative chemistries. Alternative chemistry, or 

chemical substitution, is the use of chemicals with lower global warming potential (GWP) or no 

GWP as an alternative to PFCs. Alternative chemistry also includes high GWP gases that are 

more efficiently used in plasma processes, thereby reducing overall greenhouse gas emissions. 

When evaluating alternative chemistries, criteria must include process performance, review of 

ESH risks, material availability and cost, and characterization of process emissions and 

byproducts. Fluorocarbons will generate CF4 and possibly C2F6 and C3F8 byproducts when used 

in plasma processes; the amount of input chemical converted to a PFC byproduct must be 

quantified to ensure an accurate accounting of PFC emissions. Additionally, any fluorinecontaining compound used in the presence of carbon in a plasma process, such as cleaning of an 

organic low-k deposition chamber, will form some quantity of PFC such as CF4 and, possibly, 

C2F6. 

Since fluorocarbons appear to generate other PFCs and COF2 while NF3 increases F2, HF, and 

NOx emissions, focusing solely on reducing PFC emissions may generate additional ESH 

concerns. 

4.4.1 Chamber Clean: ≤150 mm and Older 200 mm Process Tools 

The predominant semiconductor PFC emission is C2F6 from CVD chamber cleans on ≤150 mm 

and older 200 mm process tools. C2F6 is used at 30% efficiency in typical chamber clean 

processes, resulting in 70% of the input gas being emitted [10]. Additionally, a typical C2F6

plasma chamber clean process converts ∼10% of the input C2F6 into CF4 on a mass per mass 

basis. As seen in Table 1, several replacements for C2F6 have been demonstrated and 

implemented in manufacturing fabs. 

Table 1 Implemented Alternative Chamber Clean Chemistries 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation as % of Gas 

Input (%) (mass/mass) 

% PFC Emissions 

Reduction from 

Baseline C2F6 Process 

C3F8 30–60 12–30 (CF4) 12–70 

c-C4F8 70–90 4–11 (CF4) 50–85 

C4F8O 85–90 10–20 (CF4); 4 (C3F8) 70–90 

NF3 60–80 0–4 (CF4) 

depending on carbon content of film removed 20–90 

C3F8, c-C4F8, and C4F8O are drop-in replacements for C2F6 (i.e., new gas lines or additional ESH 

systems do not need to be installed). As Table 1 shows, significant amounts of CF4 byproduct 

can be produced with the drop-in replacements; therefore, the amount of O2 added to the clean 

process must be optimized to drive the reaction to COF2, a highly toxic but water-scrubbable 

byproduct, instead of CF4. Note that at least one semiconductor manufacturer has also identified 

the PFC byproduct C3F8 when using C4F8O. Whereas decreased COO is reported when using the 
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drop-in replacement chemistries in lieu of C2F6 (because of decreased clean gas consumption), 

the impact on emissions is variable. In addition to determining utilization efficiency, all of the 

PFC byproducts must be quantified to determine the total effect on emissions. 

NF3 is the most effective alternative chemistry currently used in manufacturing fabs when 

viewed in terms of clean time, carbon equivalent emissions (a metric used to compare different 

greenhouse gases based upon their global warming potential), and gas usage [11]. IBM 

implemented in situ NF3 cleans to replace C2F6 at their Burlington, VT, manufacturing facility 

[12], and Novellus has developed dilute in situ NF3 clean processes to replace C2F6 in their 

advanced 200 and 300 mm tools [13]. However, NF3 is not a drop-in replacement. Unlike the 

fluorocarbon alternative chemistries in Table 1, NF3 is an oxidizer. The use of NF3 precludes the 

generation of fluorocarbon byproduct unless organics are present; however, plasma chemistries 

are complex and use of an in situ NF3 clean process may increase emissions of HF and F2 as well 

as NOx. Additional ESH controls, such as local scrubbing, may be required; additionally, one 

semiconductor manufacturer recommended installing a coated stainless steel exhaust duct [7]. 

On a mass basis, NF3 has a higher cost per kilogram than C2F6 and the other fluorocarbon 

replacements; however, that cost may be offset by decreased consumption and faster clean times. 

CF4 is used in certain older plasma enhanced (PE)CVD silane deposition chambers for chamber 

cleaning. One semiconductor manufacturer reported using C2F6 as an alternative chemistry, 

reducing PFC emissions by >57% from the baseline CF4 process. 

4.4.2 Chamber Clean: Advanced 200 mm and 300 mm 

Because of significantly lower PFC emissions and process benefits, CVD tool supplier Applied 

Materials has standardized remote NF3 cleans for their advanced 200 mm and 300 mm tools 

while Novellus has adopted in situ NF3 cleans for their corresponding tools. Remote plasmas use 

NF3 with 95–99% efficiency, whereas in situ processes use NF3 with 60–80% efficiency [14]. 

The lower utilization efficiency of in situ cleans may require additional abatement; however, NF3

is abated with most PFC abatement technologies. Destruction-removal efficiencies of 95–99.9% 

have been reported. 

4.4.3 Chamber Clean: Research and Development 

Several chamber clean chemistries are in research and development. From 1998–2002, Japan’s 

Research Institute of Innovation Technology for the Earth undertook an effort to identify 

alternative chamber clean chemistries, eventually recommending carbonyl fluoride (COF2) as a 

replacement gas. With a GWP of 1 [15], COF2 has a much lower global warming potential than 

other fluorocarbons used for chamber cleans, and, although COF2 is toxic, it is easily removed 

from the exhaust stream by water scrubbing. At the 12th ISESH Conference in 2005, JEITA-JSIA 

members presented results of COF2 evaluations in manufacturing environments. COF2 cleans 

reduced PFC emissions 96% with process performance equivalent to PFCs [16] [17]; however, at 

a cost of 20,000Yen/kg (~$175/kg), COF2 is currently not a cost-effective alternative. 

Chlorine trifluoride (ClF3) was mentioned in the 1998 report as a potential alternative chamber 

clean gas for polysilicon and nitride chambers. Although ClF3 has no GWP or ozone depletion 

potential, it has not been widely adopted in the industry because of its extreme reactivity and the 

risks and costs associated with safe storage and use. In fact, efforts have been undertaken to 

replace ClF3 with alternative chemistries such as NF3 and fluorine [18]. 

Fluorine (F2) has been discussed as a possible alternative to PFCs for CVD chamber cleaning but 

was not considered a serious alternative in the past because of the ESH risks associated with 
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transport, storage, and use of high pressure F2 cylinders. These problems have been addressed by 

two companies that have developed POU fluorine generators [19][20]. POU F2 generators 

convert anhydrous HF into F2 by electrolysis. After the F2 is generated, it is purified to remove 

residual anhydrous HF and other contaminants. While anhydrous HF is toxic and corrosive and 

F2 is highly toxic and a strong oxidizer, neither of these materials are global warming gases. 

When used to clean organic low-k deposition chambers, F2 generates a small quantity of PFC 

byproduct such as CF4. 

4.4.4 Plasma Etch 

While replacing high GWP gases with lower or non-GWP gases is generally preferable, it has 

not proven feasible in most plasma etch applications. Processing requirements for high aspect 

ratio plasma etching continue to become more stringent, requiring both fluorine to etch and the 

right carbon-to-fluorine ratio to ensure anisotropic etching. While a significant amount of 

research has been done on alternative etchants such as iodofluorocarbons, hydrofluorocarbons, 

and unsaturated fluorocarbons [21]–[24], many of these chemicals are not feasible alternative 

etchants in a manufacturing environment because of excess polymerization, lack of etch 

selectivity, difficulties in delivering gases to the process chamber, and potential increased 

employee exposure risks. An exception is hexafluoro-1,3-butadiene (C4F6) for oxide and low-k 

etching where high selectivity to silicon is required in the presence of nitride or other films with 

high aspect ratios, thinner resists, and less etch resistant resists. In these cases, C4F6 replaces CF4, 

CHF3, and C4F8 [24]. With an atmospheric lifetime <1 year and utilization efficiency >95%, PFC 

emissions can be reduced by >90% compared to baseline CF4, CHF3 and C4F8 processes [26]; 

however, as is the case with all higher molecular weight fluorocarbon compounds used in plasma 

processes, some CF4 byproduct is formed and emitted. 

4.5 Capture/Recovery 

Several semiconductor manufacturers and suppliers conducted alpha and beta evaluations of PFC 

capture/recovery systems that could be installed as a central, building-wide means for handling 

PFC emissions [26]–[30]. Technologies evaluated include membrane separation, cryogenic 

recovery, and pressure swing adsorption/desorption. No evaluation resulted in successful re-use 

of PFC; all were deemed to be too costly to implement. Capture/recovery technology requires 

extensive pretreatment of the process tool exhaust stream to remove corrosives, pyrophorics, 

moisture, and particulate. Historically, chamber clean PFCs make up the majority of PFC 

emissions. As NF3-based cleans proliferate, large building-wide capture/recovery systems 

become less cost-effective due to the reduced volume of PFCs available for recovery. To date, no 

semiconductor facility in the world has successfully implemented centralized capture/recovery 

technology. 

As new, lower emitting chamber cleans are implemented and older fabs are decommissioned, the 

mix of PFC emissions is expected to change. JEITA-JSIA projects that, in 2010, the largest 

quantity of PFC emitted from Japan’s semiconductor facilities will be SF6. In addition to plasma 

etch processes, SF6 can be found in specialized processes such as IC testing and wafer thinning 

where it is used in large volume. Air Liquide presented data on a semi-centralized membrane 

system used to capture and recycle SF6 [31]. In the Air Liquide application, SF6 was being used 

in large volume as a blanket gas, not as a plasma etchant. Byproducts requiring pre-treatment 

were not present in the exhaust stream; therefore, SF6 could be captured and re-used in the 

process, thus reducing process cost of ownership due to reduced virgin SF6 purchases. While 

centralized capture/recovery does not appear to be a cost-effective way to reduce PFC emissions, 
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smaller capture/recovery systems may be appropriate, as demonstrated in the Air Liquide case, 

for niche, single PFC, high volume processes. 

4.6 Abatement 

Since the publication of ref. [1], many new PFC abatement technologies have been developed 

and new systems commercialized. The industry has favored POU over centralized EOP 

abatement for PFCs, believing that it is more effective to abate close to the source and, thus, 

before dilution; however, one semiconductor company has recently installed an EOP abatement 

system that uses corona discharge plasma technology to destroy PFCs from CVD chamber 

cleans. Most abatement technologies can be applied to PFC emissions from both etch and CVD 

processes, although several companies have developed plasma abatement systems specifically 

for etch chamber emissions. These are typically installed before the vacuum pump (i.e., the 

foreline) to avoid dilution of the stream with pump-purge N2. Because it is desired to abate 

certain CVD processes for deposition gases, some semiconductor manufacturers have elected to 

install POU abatement technology that can also abate PFC emissions. 

As noted earlier, fluorocarbons will generate CF4 and possibly C2F6 and C3F8 byproducts when 

used in plasma processes. Additionally, the use of any fluorine-containing compound in the 

presence of carbon in a plasma process will form some quantity of CF4. Certain abatement 

devices sold for PFC applications are not capable of destroying CF4 effectively. 

Abatement manufacturers may use different methods of determining destruction/removal 

efficiency (DRE) because the industry has not developed a standardized method. This can make 

a direct comparison of abatement technologies difficult. Performance of abatement systems 

varies greatly depending on a variety of abatement device and process parameters such as 

temperature, PFC inlet concentration, flow rate, overall inlet stream composition, etc. In 

addition, consumables, maintenance, and utilities have a significant impact on COO. 

Technologies under development or proven to be effective in abating PFC emissions from 

specific applications are listed in Table 2. 

Table 2 PFC Abatement Technologies 

Technology Type Description and Applicability 

POU Fueled Burner – Scrubber Uses a propane, methane, natural gas or hydrogen flame to destroy PFCs 

and other hazardous substances such as deposition precursors followed by a 

water scrubber, which may contain a base solution, to remove volatile acid 

gases from the exhaust stream. May not be effective in abating CF4. Burnerscrubber units are installed on the process tool exhaust line after the vacuum 

pump and, thus, the exhaust stream entering the unit contains a large amount 

of N2 that can lower the combustion unit temperature and, thus, DRE. Burnerscrubber units can typically abate emissions from multiple process chambers. 

Except for the hydrogen-fueled devices, they all generate additional 

greenhouse gases in the form of CO2. 

POU Catalytic – Scrubber Uses a catalyst to promote the destruction of PFCs and process gases at 

lower activation energies than would otherwise be needed. Catalytic systems 

operate at a lower temperature than other PFC abatement systems, are 

electrically heated, and do not require a fuel. A water scrubber typically follows 

the catalytic reactor to remove HF byproduct from the exhaust stream. May 

not be effective in abating CF4. Catalytic scrubber units are installed on the 

process tool exhaust line after the vacuum pump and, thus, the exhaust 

stream entering the unit contains a large amount of nitrogen. Catalytic 

scrubber units can typically abate emissions from multiple process chambers. 
9 

ISMI Technology Transfer #05104693A-ENG 

Technology Type Description and Applicability 

POU Electrically Heated Thermal 

– Scrubber 

Uses an electrically heated chamber to destroy PFCs and other hazardous 

substances such as deposition precursors, followed by a water scrubber to 

remove volatile acid gases from the exhaust stream. Electrically heated 

thermal-scrubber units are installed on the process tool exhaust line after the 

vacuum pump. May not achieve the high temperatures required to effectively 

abate CF4. Electrically heated-scrubber units can typically abate emissions 

from multiple process chambers. 

POU Atmospheric Plasma Uses plasma to destroy PFCs and other hazardous substances such as 

deposition precursors. The plasma chamber can be followed by a water 

scrubber, which may contain a base solution, to remove volatile acid gases 

from the exhaust stream. Atmospheric plasma units are installed on the 

process tool exhaust line after the vacuum pump and, thus, the exhaust 

stream entering the unit contains a large amount of nitrogen, which can impact 

the plasma efficacy. Atmospheric plasma units are typically designed to abate 

emissions from multiple process chambers. 

POU Pre-pump Plasma Point-of-use foreline plasma units employ a compact, low-pressure plasma 

reactor to destroy PFCs from etch processes. Foreline plasma units are 

installed on the foreline after the turbo pump but before the mechanical 

vacuum pump, where they can abate concentrated emissions before dilution 

with N2 purge from the vacuum pump. One unit is required for each etch 

process chamber. 

Centralized Atmospheric Plasma The only centralized PFC abatement system is the corona discharge system 

jointly developed by FH Co., Ltd and Samsung Electronics in Korea. A 

separate PFC exhaust line is installed post-vacuum pump to segregate CVD 

chamber clean emissions from deposition emissions. The PFC exhaust 

passes through the annular space between co-axial cylindrical electrodes 

used to sustain a corona discharge at atmospheric pressure. Exhaust from the 

abatement system then flows to the house scrubber for removal of acid gases. 

5 INDUSTRY APPLICATION OF EMISSION REDUCTION OPTIONS 

The age, size, and infrastructure of a fab are the factors that have the greatest impact on the 

applicability of PFC emission reduction technology. For instance, older fabs process smaller 

wafers, are typically smaller in size, and may have space and infrastructure constraints such as a 

lack of or undersized utilities required to support specific reduction technologies; moreover, 

manufacturers of the process tools in older fabs are typically no longer supporting those tools 

with new process development. WSC member companies were surveyed to determine the 

technologies that they are implementing to reduce emissions. Table 3 summarizes the PFC 

emissions reduction options the industry is applying to fabs processing various wafer sizes. 

Table 3 PFC Emissions Reduction Options 

Tool Type ≤150 mm Fabs 

Old Technology 

200 mm 

Advanced 200 mm and 300 

mm 

CVD 

Fab Decommission 

Process Optimization 

Endpoint Detection 

Alternative Chemistries 

Limited Abatement 

Process Optimization 

Endpoint Detection 

Remote NF3 Cleans 

Alternative Chemistries 

Abatement 

NF3-based Cleans 

F2 Cleans 

Endpoint Detection 

Abatement 

Etch 

Fab Decommission Limited Abatement 

Limited Capture/Recovery 

Alternative Chemistries 

Abatement 

Limited Capture/Recovery 
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Technology Transfer #05104693A-ENG ISMI 

The industry is steadily decommissioning ≤150 mm fabs, eliminating them as a source of PFC 

emissions. The ≤150 mm fabs that continue operations may have few choices of emissions 

reduction technologies because of space and infrastructure constraints. For ≤150 mm fabs, 

process optimization and drop-in alternative chemistries for CVD cleans may be the only 

alternatives for reducing emissions, although a few ≤150 mm fabs have installed abatement on 

certain CVD processes. 

For older 200 mm fabs with CVD tools using C2F6 cleans, the industry has focused their PFC 

reduction efforts on CVD emissions. Process optimization, installation of endpoint detection, 

installation of remote NF3 cleans, and alternative clean chemistries are the most prevalent means 

of reducing emissions. One company reported installing abatement in an older 200 mm fab; 

however, abatement typically requires floor space that may be limited in an existing fab and 

could require facilities services that are not available. If etch emissions abatement is also needed, 

the small footprint pre-vacuum pump plasma systems may be the only alternative to reduce 

emissions. Capture/recovery may be appropriate for specialized high volume PFC applications. 

Based on the survey, the industry and its suppliers have integrated low emission CVD tools into 

advanced 200 mm and 300 mm fabs. If an advanced CVD tool uses silane or other flammable or 

pyrophoric precursors and in situ NF3 cleans, burner-scrubber abatement with high DREs for all 

these emissions is available and in use in some fabs. Companies also report using endpoint 

detection to minimize PFC gas consumption. With the advent of low emission clean processes, 

300 mm etch is expected to gain an increasing share of the industry’s total PFC emissions. Some 

companies report using alternative etch chemistries to reduce emissions; however, 

implementation of alternative etchants as a retrofit is costly and time-consuming. Because etch 

occurs on the wafer surface, process changes require extensive evaluation and process 

requalification before implementation. Several companies report using abatement technologies to 

reduce etch emissions in their advanced 200 mm and 300 mm fabs, and one company is using a 

central EOP plasma unit to abate CVD emissions from an advanced 200 mm fab. Additionally, 

capture/recovery may be appropriate for specialized high volume PFC applications. 

6 IMPACT OF INDUSTRY CHANGES ON EMISSIONS 

Since publication of ref. [1], the industry has undergone significant changes that impact PFC 

emissions. These changes include development and implementation of new chamber clean 

processes and chemistries, increased use of plasma etching and adoption of new etch gases, 

development of new materials and processes, and larger wafers to manufacture advanced 

semiconductor devices. 

6.1 Chamber Cleans 

The impact of NF3 cleans is realized principally in advanced 200 mm and 300 mm fabs; 

however, in 2004, ∼66% of the total silicon demand was processed in older technology fabs 

(≤150 mm and older 200 mm) using fluorocarbon-based cleans. In fact, C2F6 still accounted for 

∼48–50% of the industry’s total PFC emissions in 2004 [33]. A transition from C2F6 cleans to 

alternative processes and chemistries is evidenced by some associations reporting reductions in 

C2F6 emissions and increasing NF3 or C3F8 emissions. Note, however, that the associations that 

reported increased C3F8 emissions in 2004 also reported increases from 2003 levels in overall 

PFC emissions, despite the transition to C3F8. 
11 

ISMI Technology Transfer #05104693A-ENG 

6.2 Etch 

In interviews, semiconductor etch professionals [33] provided input on PFC usage in etch over 

time. They agreed that the move from 200 mm to 300 mm equipment has resulted in a 1.5–2X 

increase in etch PFC consumption per wafer pass; however, they noted that the increased usage 

is less than would be expected based on the 2.25X increase in wafer area. 

The increase in microprocessor metal levels from four in 1995 to 11 in 2004 has led to an 

increase in back-end etch PFC usage. Due to requirements for higher selectivity to resist and 

underlying films, c-C4F8 and C4F6 are now being used more extensively for dielectric etching, 

replacing CHF3 and CF4. Both chemistries generate C2F4, CF4, C3F8, C2F6, CHF3, and some C4F8

byproducts; however, MIT and Motorola’s Semiconductor Product Sector (now Freescale 

Semiconductor) demonstrated equivalent process performance and a 65–82% reduction in PFC 

emissions for organosilicate glass and oxide etching when using C4F6 in lieu of c-C4F8 [34]. 

Experts note that as device line and contact sizes are scaled, the aspect ratio remains the same; 

therefore, films are becoming thinner and etch times shorter, thereby decreasing PFC usage. 

However, one expert cautioned that selectivity requirements are becoming more critical with the 

thinner layers and required process changes may result in increased PFC consumption over time. 

The impact of ultra low-k dielectrics on PFC emissions cannot be ascertained at this time 

because it is too early in their development stage. 

In the front-end, integrations using multiple spacers and sometimes multiple polysilicon layers 

have increased PFC usage. As high-k dielectrics and gates are implemented, increased etching 

could further increase PFC consumption. It is too early to quantify the impact of novel structures 

such as FinFET on PFC emissions. 

In recent years, semiconductor tool suppliers have evaluated in situ cleans or dry cleans for etch 

tools to maximize tool uptime and increase mean time between wet cleans (MTBC) [35]. While 

oxygen can be used to clean organic byproducts of the resist from the chamber walls, fluorinecontaining gases are required to remove silicon-based residues. The use of in situ cleans is likely 

to increase PFC emissions from etch tools. 

One etch expert estimates that the industry can anticipate a net 2% increase in PFC consumption 

and, therefore, emissions each year [36]. With increasing usage of NF3-based cleans in 300 mm 

fabs, etch will become a significant source of 300 mm PFC emissions. 

6.3 Future Technologies That May Impact PFC Emissions 

Atomic layer deposition (ALD) is used increasingly in the industry to deposit back-end copper 

barriers and seed layers. In the front-end, ALD is being used to deposit metal gates and high-k 

dielectrics. These materials replace films that formerly were deposited by diffusion processes 

that did not have PFC chamber cleans. In situ and remote plasma NF3-based chamber cleans are 

currently in development to replace cleans that require the chamber be taken down to remove 

parts. Non-PFC chemistries are also being evaluated for in situ or remote plasma chamber cleans. 

Finished semiconductor wafers contain multiple computer chips called dies. The finished dies 

are cut, packaged, and then sent to manufacturers to integrate into products such as cell phones, 

computers, personal music players, and automobiles. The shrinking size of electronic products 

requires that packaged integrated circuits be reduced in thickness and footprint. Thin IC 

packages require thinner dies; additionally, fully depleted silicon on insulator (SOI) used for low 

power, high speed devices also requires thinning of SOI wafers. The four major methods of 

reducing die thickness are mechanical grinding, chemical mechanical planarization (CMP), wet 
12 

Technology Transfer #05104693A-ENG ISMI 

etching, and atmospheric downstream plasma (ADP) etching [37]. ADP etching requires PFCs; 

however, it is not certain that ADP will be the technology of choice for wafer thinning. 

3D interconnect—stacking chips and connecting them through vias on the die—is a technology 

being pursued to shorten interconnects and decrease delay time [38]. 3D interconnects will 

employ wafer and die thinning technology, but those are most likely to be wet chemical- or 

CMP-based. The technology will require an additional metal deposition; however, it is hoped 

that new architecture will eliminate an existing layer of metal and the metals changes will be 

PFC-neutral. An additional etch step is required, but again chip redesign is anticipated to 

eliminate levels and reduce etch process steps. 

6.4 Changes in Wafer Size 

The change with the largest impact on PFC emissions over time is increasing wafer size and the 

corresponding advanced processing technologies. Older technology ≤150 mm wafers constituted 

the bulk of wafer demand in 1995. Between 1995 and the present, ≤150 mm wafer demand has 

steadily declined. VLSI Research projects that ≤150 mm wafer demand will be 54% below 1995 

levels in 2005 and 73% below those levels in 2010 [40]. Nine semiconductor manufacturers 

(1 based in Europe, 2 in Korea, and 6 in the U.S.) provided information on actual and projected 

PFC emissions per fab type in 1995, 2000, 2005, and 2010 [41] While all nine companies 

indicated PFC emissions from ≤150 mm fabs in 1995, five were emitting PFCs from those fabs 

in 2005 and only four expect to be emitting PFCs from ≤150 mm fabs in 2010. Both the industry 

survey results and VLSI Research wafer demand projections are clear indicators of the industry 

trend to close and decommission older technology fabs. PFC emissions increased between 1995–

2000 as first generation 200 mm fabs using predominantly C2F6 cleans ramped up; 200 mm 

wafers became the predominant wafer type by 2000. As advanced 200 mm and 300 mm wafer 

fabs began ramping in 2001–2004, the normalized rate of emissions (PFC emitted/cm2) 

decreased, most likely due to use of NF3-based chamber clean processes. An estimate of the 

percentage of 200 mm wafer demand attributable to older technology fabs versus advanced fabs 

can be made by assuming that the additional demand above 1999 levels is due to advanced fabs. 

Based on these estimates, worldwide, advanced 200 mm and 300 mm fabs will account for 

approximately 70% of semiconductor manufacturing wafer demand in 2010 [41][42] (Figure 1). 

The semiconductor industry has experienced significant growth from 1995 to 2004 with wafer 

demand increasing 52% [42]. As seen in Figure 2, while silicon demand has increased, PFC 

emissions per square inch of silicon increased from 1995–2000 and then began decreasing from 

2001–2004. The decreasing trend can be explained by the transition to advanced 200 mm and 

300 mm wafer fabs coupled with a change in chamber cleaning technology between older and 

newer fabs. Newer fabs employ NF3-based cleans that result in much lower PFC emissions than 

C2F6 cleans. If older manufacturing facilities are shut down, C2F6-based cleans will be reduced. 

Based on the changes brought about by the shift to larger wafer sizes and the accompanying 

transition from old technology to new, trends indicate that the normalized rate of PFC emissions 

will continue to decline through 2010. 
13 

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

199519961997

199819992000

2001

2002200320042005200620072008

2009

2010

Time

Percent of Total Wafer Demand

Fraction New Technology

Fraction of Total Old 200 mm

Fraction of Total (<=150 mm)

Figure 1 Wafer Demand Over Time (1995–2010) 

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Time (Year)

WSC Emissions/Wafer Demand

(mmtce/total wafer area)

Figure 2 WSC Production Normalized PFC Emissions Over Time 

ISMI Technology Transfer #05104693A-ENG 
14 

7 SIA PROGRESS TOWARDS 10% EMISSIONS REDUCTION GOAL 

The SIA partners have achieved significant reductions in PFC from their 1999 peak level 

emissions, meeting the 10% goal in 2003 and exceeding the goal in 2004 (Figure 3). SIA 

reductions have been achieved through process optimization, alternative processes, alternative 

chemistries, and abatement. In addition, some older fabs have been closed while some newer 

fabs have been built that use lower emission technologies and more abatement. 

While much has been written about the shrinking of the U.S. semiconductor industry, SIA 

reductions are not due solely to fab closures. From 1995–2004, North American fabs increased 

wafer demand by 55% as measured in wafer area [42] in spite of fab closures. 

0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.6

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

Emissions (mmtce)

10% Reduction Goal

Figure 3 Annual SIA PFC Partner Emissions 

8 PROJECTED WSC EMISSIONS 

All of the associations are demonstrating a decrease in normalized emissions (million metric tons 

of carbon equivalent [MMTCE]/square inch of wafer demand); however, absolute emissions in 

2004 are 0.5–1.3X for four of the five associations. The industry has consistently reduced PFC 

emissions per square inch of silicon since 2000 (Figure 2). A linear regression analysis of the 

2001–2004 normalized emission data results in an R-squared value of 0.99. Assuming this trend 

continues, emissions can be projected through 2010 using a linear extrapolation. Figure 4 shows 

historical WSC-indexed emissions, as well as projected WSC-indexed emissions from 2005–

2010, based on this linear extrapolation and VLSI Research, Inc. wafer demand projections. 

Indexed emissions are actual emissions divided by the WSC 2010 goal. An index value of 1.0 is 

equivalent to the 2010 goal. Because KSIA and TSIA joined the WSC after 1995, their emissions 

are not included in 1995 and 1996, resulting in indexed emissions for those years that are less 

than the overall WSC goal. While VLSI Research predicts increased wafer demand from 2005–

2009, the predicted demand is expected to decrease from 2009 to 2010. Assuming the 

normalized emissions rate trend continues and that VLSI’s projected demands are accurate, WSC 

emissions are projected to be lower than the 2010 reduction goal. 

Technology Transfer #05104693A-ENG ISMI 
15 

ISMI Technology Transfer #05104693A-ENG 

0.60

0.80

1.00

1.20

1.40

1.60

1.80

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Year

WSC Indexed Emissions

(Emissions/Target Level)

WSC Target Level

Actual Projected

Figure 4 WSC Indexed PFC Emissions – Actual and Projected 

9 DISCUSSION AND ANALYSIS 

Following the pollution prevention hierarchy, many technologies have been developed in recent 

years to reduce PFC emissions. Based on the current state of those technologies as described in 

this report, several factors related to their applicability and implementation should be considered. 

9.1 Applicability of Technologies 

The applicability of PFC emission reduction technology depends on the age, size, and 

infrastructure of a fab. In 2004, the largest PFC emission continues to be C2F6, at 48–50% of 

total semiconductor PFC emissions. C2F6 emissions are expected to decrease over time as 

300 mm fabs with NF3- and F2-based cleans ramp up and as older fabs shut down. 

For older fabs that will continue operations beyond 2009, companies may want to 

• Implement those alternative clean processes and chemistries that achieve the highest 

levels of emissions reductions, or 

• Install abatement, if feasible. 

Due to projected growth in 300 mm fabs, careful monitoring of 300 mm PFC consumption and 

CVD and etch emissions from those fabs as they ramp up are recommended. If a company’s 

300 mm fabs use CVD chamber clean technologies other than remote NF3 or F2 cleans, the 

amount of CVD PFC emissions need to be evaluated to determine if additional measures should 

be implemented to further reduce emissions. 

Etch emissions are expected to grow over time and may become the major source of 300 mm 

PFC emissions. Because etch processes are already optimized to achieve the required process 

performance, alternative chemistries and process optimization are typically not feasible. 

Abatement may be the only option if further emissions reductions are needed. 
16 

Technology Transfer #05104693A-ENG ISMI 

9.2 Process Optimization/Alternative Processing 

By itself, process optimization may not reduce emissions sufficiently to enable industry 

associations to meet the goal. Because of other benefits including cost reduction and pollution 

prevention, however, it should be used on all CVD chamber cleans to minimize chemical 

consumption and waste generation. 

The alternative process remote cleans minimize PFC emissions. Additionally, they may offer 

process, yield, and COO benefits. In older fabs, replacing C2F6 cleans with options such as 

remote cleans, in situ NF3 cleans, or alternative chemistries is likely to be the most cost-effective 

means to minimize PFC emissions. The impact of increased F2 emissions must be addressed 

when designing exhaust systems and wastewater treatment systems. 

9.3 Alternative Chemistries 

Alternative chemistries are being used to replace C2F6/O2 chamber cleans in older process tools. 

These chemistries must be chosen carefully to ensure tangible benefits. One WSC member 

association has shown a substantial increase in C3F8 emissions over time with a concurrent 

reduction in C2F6 emissions; however, total emissions of C2F6 and C3F8 in 2004 exceed the 

highest historical C2F6 emission. This may indicate the C3F8 does not provide the level of 

emissions reduction needed to reduce overall emissions in line with the growth of wafers 

processed. 

When evaluating alternative chemistries, criteria must include the following: 

• Process performance 

• Review of ESH risks 

• Alternative chemistry availability and cost 

• Process emissions and byproducts characterization 

Choosing an alternative based solely on its utilization efficiency may raise additional ESH 

concerns. For example, fluorocarbon-based alternatives generate difficult-to-abate CF4

byproducts and, potentially, other fluorocarbon byproducts. The use of NF3 generates increased 

F2, HF, and NOx emissions. While resulting in minimal PFC emissions, F2 is highly toxic and 

reactive, thus requiring significant ESH controls, such as double contained piping, toxic gas 

monitoring, abatement, and possibly upgrading of exhaust ducts. 

While alternative etchants have been extensively researched, C4F6 appears to be the only 

alternative evaluated so far that provides the required process performance while reducing 

emissions. 

9.4 Capture/Recovery 

Although centralized capture/recovery has not proven cost-effective, smaller capture/recovery 

units may be appropriate in specialized cases when a process uses a single PFC in large volume 

without plasma processing, resulting in emissions of a high volume, relatively clean PFC stream. 

9.5 Abatement 

The number and type of commercially available PFC abatement systems has increased 

dramatically since the first Current State of Technology: Perfluorocompound (PFC) Emissions 
17 

ISMI Technology Transfer #05104693A-ENG 

Reduction [1] report was issued. Abatement devices range from those that are commercially 

available with hundreds installed in semiconductor applications to alpha and beta units. Some 

abatement devices can be used only in specific applications. DRE and COO can vary greatly 

from one abatement device to another. 

When using PFC abatement, semiconductor manufacturers should establish performance 

standards for the following: 

• Maximum downtime allowable 

• COO 

• Minimum DRE 

Abatement devices typically have consumable parts that must be replaced; the parts requiring 

replacement, frequency of replacement, and equipment downtime costs should be understood. 

Because a standard method to calculate DRE does not currently exist, comparing the results of 

one abatement device to another is difficult. Many abatement technologies use additives that 

dilute the exhaust stream; these additives must be taken into account by determining the total 

dilution across the system. Semiconductor manufacturers must ensure that a PFC abatement 

device is capable of performing in the specific application for which it is required. DRE data 

generated from an abatement device installed on a 200 mm etch process are not likely applicable 

to the same etch process on a 300 mm tool because of increased PFC gas flows and other process 

variations. Additionally, the total amount of exhaust flow through an abatement device can vary 

from one application to another. 

Fluorocarbons in plasma processes can generate a significant amount of CF4. When installed on 

fluorocarbon processes, the ability of an abatement device to abate CF4 must be understood; 

moreover, to minimize total PFC emissions, the device must effectively abate CF4, the PFC most 

difficult to abate. 

Finally, once installed, semiconductor manufacturers must ensure that PFC abatement devices 

are operated and maintained according to the abatement device manufacturer’s specifications to 

ensure that DRE is maintained over time. 

9.6 Impact of New Process Technology 

It is not anticipated that new processing technologies will have a significant impact on PFC 

emissions before 2010; however, they do have the potential to impact emissions beyond 2010. 

Thus, it is recommended that the industry monitor the development and implementation of 

manufacturing technologies such as wafer thinning, ALD, and in situ dry cleans as well as new 

front-end integrations and materials and 3D interconnects. If possible, these technologies should 

be developed without using PFCs or by using those PFCs and processes that result in the lowest 

levels of emissions; however, new manufacturing technologies may not be possible without 

PFCs. 

If new technologies require PFCs, processes should be developed that 

• Minimize the amount of PFC required 

• Maximize PFC utilization efficiencies 

• Minimize formation of PFC byproducts 
18 

Technology Transfer #05104693A-ENG ISMI 

If PFC emissions from these new technologies become significant, efforts should be made to 

employ capture-recovery (for high volume streams) or to abate emissions. 

10 CONCLUSIONS 

As the first industry to coordinate globally and establish a voluntary greenhouse gas emissions 

reduction goal, the semiconductor industry has established itself as a leader and model for other 

industrial sectors. The world semiconductor industry has demonstrated significant commitment 

to reducing PFC emissions. The U.S. semiconductor industry achieved the 10% reduction goal in 

2003 and surpassed the goal in 2004, despite a significant increase in wafer demand over time. If 

the current normalized PFC emissions trend continues and wafer demand projections are 

accurate, the world-wide industry will achieve the 2010 goal; however, these trends and 

projections largely depend on the ramping up of lower emitting advanced 200 mm and 300 mm 

fabs and a decrease in the emissions from older, higher emitting fabs. 

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ISMI Technology Transfer #05104693A-ENG 

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2003. 

[25] “Reduction of PFC Emissions to the Environment Through Advances in CVD and Etch 

Processes,” A.D. Johnson, R.G. Ridgeway, and P.J. Maroulis, IEEE Transactions on 

Semiconductor Manufacturing, 17, p.491, November 2004. 

[26] Semiconductor Industry and Supplier Survey Results, Laurie Beu (2005). 

[27] “Intel PFC Recovery Project,” K. Hasserjian, Proceedings of the 1998 Monterey Global 

Semiconductor Industry Conference on Perfluorocompound Emissions Control, Session 6, 

Paper #3 (1998). 

[28] Evaluation of Praxair’s Perfluorocompound (PFC) Capture/Recovery System, 

Technology Transfer #98113600A-ENG, T. Gilliland and C. Hoover, International 

SEMATECH, December 1998. 

[29] “Process Gas Recycling System,” T. Hashimoto, Y. Kishida, Y. Shirai, T. Ohmi, M. Itano, 

and H. Aoyama, Proceedings of the Fifth International ESH Conference of the 

Semiconductor Industry, Session 11, paper #4, 1998. 
20 

Technology Transfer #05104693A-ENG ISMI 

[30] “Recovery of Perfluorocompounds (PFCs) from Semiconductor Manufacturing Processes 

Using a Membrane-based System,” M. Foder, R. Wimmer, J. Yang, and T. McCay, 

Proceedings of the Electrochemical Society, 99–8, p.60, 1999. 

[31] “On-Site PFC Recovery System for Multiple Tool or Fab-wide Emissions Reduction: An 

Update of Recent Operations,” M. Foder, G. Crossland, E. Bell, T. Booth, K. Christian, 

R. Ridgeway, and J. Yang, Proceedings of the SEMICON Southwest 99 A Partnership for 

PFC Emissions Reductions Seminar, oral paper I (1999). 

[32] “PFC Emissions Reduction Via Membrane Capture and Processing in Semiconductor,” 

C.H. Ly, R. Daniel, and C. Anderson; Proceedings of the 11th Annual ISESH Conference, 

PFC13, 2004. 

[33] Data provided in 2005 by ESIA, Japan Electronics and Information Technology Industries 

Association, Korean Semiconductor Industry Association, Taiwan Semiconductor 

Industry Association, and SIA. 

[34] Calvin Gabriel, AMD; Ricky McGowan, SEMATECH; and Terry Sparks, Freescale 

Semiconductor; private communication (2005). 

[35] Unsaturated Fluorocarbon Etching of Oxide and Low-k Films in High Density and 

Medium Density Toolsets Technology Transfer #02014234A-TR, R. Chatterjee, R. Reif, 

T. Sparks, V. Vartanian, L. Mendicino, and B. Goolsby, January 2002. 

[36] “Controlling Defectivity in Advanced Silicon Etch Systems,” B. Richardson, 

MicroMagazine.com. 

[37] e-Mail from Calvin Gabriel, AMD, 2005. 

[38] “Wafer Thinning: Techniques for Ultra-Thin Wafers,” M. Reiche, G. Wagner; Advanced 

Packaging, March 2003. 

[39] “SEMATECH Pushes 3D Interconnects,” J. Chappell, Electronics News, March 26, 2004. 

[40] VLSI Research Inc., Silicon Demand Forecast, Doc: 327031v5.06.1, May 2005. 

[41] Identification of old technology vs. new over time obtained through semiconductor 

industry survey conducted by L. Beu in Spring 2005. 

[42] Gartner Dataquest, August 2004. 
21 

ISMI Technology Transfer #05104693A-ENG 

APPENDIX A – Process Optimization/Alternative Processing 

A.1 Process Optimization 

Process optimization uses extractive metrology such as mass spectrometry (MS) and Fouriertransform infrared spectroscopy (FTIR) to monitor emissions and provide clean end point times 

that are minimized based on process parameters such as chamber pressure, temperature, plasma 

power, cleaning gas flow rates, and ratios in the case of mixtures. Chamber cleans are optimized 

to minimize gas consumption, thereby, lowering cost of ownership (COO) and reducing 

perfluorocompound (PFC) emissions. Cleans optimization is primarily applicable to chemical 

vapor deposition (CVD) chambers, but the technology can also be applied to etch and other 

process chambers where PFC cleans are performed on a regular basis. 

• Technology Status 

Process optimization can be completed with internal company resources, if available, or by 

contract. 

• Applicability 

Chamber cleans optimization is applicable to ≤150 mm, 200 mm, and 300 mm CVD 

reactors and to other process tools using regular PFC chamber cleans. A significant amount 

of work has been previously published on optimization of Novellus Concept One and 

Applied Materials P5000 chamber cleans. 

• Pros 

– In addition to reducing PFC emissions by up to 50%, process optimization requires no 

capital and results in decreased COO (up to 50%) due to reduced chemical usage and 

increased throughput. 

• Cons 

– Process requalification may be necessary. 

• Reported Results 

Clean 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

C2F6 33–55 7–30 (CF4) 20–50 

NF3 (in situ) 60 → 70 

0–4 (CF4) 

Depending on carbon 

content of film removed 

20–40 

NF3 (remote) > 98 

0–4 (CF4) 

Depending on carbon 

content of film removed 

>95–99 

• Cost of Ownership 

COO reductions of 20–50% are achievable. 
22 

Technology Transfer #05104693A-ENG ISMI 

• Recent Publications on PFC Process Optimization 

G. Loh, Y. Osaki, and M. Mocella, “Perfluorocompound (PFC) Emission Reduction in 

Existing Plasma Enhanced Chemical Vapor Deposition (PECVD) Tools,” Proceedings 

of the 11th ISESH Conference, PFC paper #2, 2004. 

A.D. Johnson, R.V. Pierce, M.I. Sistern, M. Kencel, R. Sward, and H. Winzig, “C2F6-based 

Chamber Clean for Silane Plasma Enhanced Chemical Vapor Deposition (PECVD), 

International Semiconductor, 27 (3), p.57, March, 2004. 

Y-d Yoo, “Perfluorocompound (PFC) (C3F8) Emission Reduction by Optimizing Cleaning 

Process,” Proceedings of the 10th Annual ISESH Conference, 2003. 

A.D. Johnson, R.G. Ridgeway, and P.J. Maroulis, “Reduction of Perfluorocompound (PFC) 

Emissions to the Environment Through Advances in Chemical Vapor Deposition (CVD) 

and Etch Processes," IEEE Transactions on Semiconductor Manufacturing, 17, p.491, 

2004. 

V. Vartanian, B. Goolsby, R. Chatterjee, R. Kachmarik, D. Babbitt, R. Reif, E. Tonnis, and 

D. Graves, “Reduction of Semiconductor Process Emissions by Reactive Gas 

Optimization,” IEEE Transactions on Semiconductor Manufacturing, 17, p.483, 2004. 

• Contacts 

Robert Ridgeway, Air Products and Chemicals, Inc., 610-481-4436, 

ridgewrg@airproducts.com

Gary Loh, DuPont, 302-999-4971, gary.loh@dupont.com

• References 

Information on process optimization was provided by SIA member companies including 

Laura Mendicino of Freescale Semiconductor, by Francesca Illuzzi of STMicroelectronics, 

Robert Ridgeway of Air Products & Chemicals, Inc. and Gary Loh of DuPont. 

A.2 Endpoint Detection 

• General Technology Description 

Endpoint detection uses techniques such as MS, infrared (IR) spectroscopy, optical emission 

spectroscopy (OES), and radio frequency (RF) impedance monitoring to monitor changes 

and provide plasma process end point times. PFC gas consumption and emissions can be 

minimized by determining chamber clean end points and optimizing process parameters 

such as chamber pressure, temperature, plasma power, cleaning gas flow rates, and ratios in 

the case of mixtures. Endpoint detection has been used extensively for CVD chamber cleans, 

but the technology can also be applied to etch and other PFC plasma processes. 

• Technology Status 

Commercially available for use in ≤150 mm, 200 mm, and 300 mm CVD and etch reactors. 

Many process tool suppliers offer supplier supported endpoint detection systems and 

processes. Endpoint detection can also be installed as a retrofit. 

• Applicability 

Endpoint detection is applicable to ≤150 mm, 200 mm, and 300 mm CVD and etch reactors. 
23 

ISMI Technology Transfer #05104693A-ENG 

• Pros 

– Reduced PFC emissions due to decreased process time. 

– Decreased COO. 

– Possible increase in process throughput. 

• Cons 

– As a retrofit, endpoint detector must be purchased and installed which could require 

capital expenditure. 

• Reported Results 

An un-named SIA member company reports 40% PFC emissions reduction from baseline 

process for ≤150 mm and 200 mm Applied Materials and Novellus C2F6-based cleans. 

Philips reports PFC emission reductions of 29–53% and C2F6 gas usage reductions of 34–

47% on borophosphosilicate glass from a TEOS oxysilane source (BPTEOS), undoped 

silicate glass (USG), and SiN clean processes 

• Recent Publications 

R. Dam, “Optimization of C2F6-based Plasma Enhanced Chemical Vapor Deposition 

(PECVD) Chamber Cleaning Process Minimizing Perfluorocompound (PFC) Emissions 

and Operating Costs on a Novellus C-2 Platform,” Proceedings of the 10th Annual 

ISESH Conference, (2003). 

• References 

Information provided by Harry Thewissen of Philips and an SIA member company. 

A.3 Remote Plasma Cleans 

• General Technology Description 

Remote plasma clean technology was developed as an alternative to in situ CVD chamber 

cleans to clean the deposition byproducts left in the chamber after wafer processing. With 

remote chamber clean, a plasma-generating unit is mounted on the lid of a CVD chamber. 

Remote cleans typically react NF3 or C3F8 in a plasma. The fluorine radicals and ions 

generated in the remote plasma unit are routed to the processing chamber where they 

chemically react with deposits. The deposition byproducts are then carried away in gaseous 

form, e.g., SiF4. 

• Applicability 

This technology is commercially available for 200 mm and 300 mm CVD chamber cleans. 

Remote cleans is the process of record (POR) for Applied Materials advanced 200 mm and 

300 mm PECVD chamber cleans. Several suppliers manufacture or integrate remote plasma 

systems for retrofits to existing process tools to replace in situ PFC cleans. 

• Pros 

– Commercially available technology from several suppliers that reduce chamber clean 

PFC emissions by 99%. 

– Significantly reduced PFC emissions from CVD chamber cleans. 
24 

Technology Transfer #05104693A-ENG ISMI 

– Remote cleans result in improved tool utilization through reduced clean times, reduced 

wet clean frequency, improved mean time between failures (MTBF), reduced chamber 

parts costs. Additionally, they improve yield through reduced defects and decrease 

COO. 

– CVD tools not equipped with remote cleans may be retrofitted with remote cleans. 

• Cons 

– Implementing NF3 remote cleans results in generation of much greater F2 and HF 

emissions than fluorocarbon-based cleans, and requires additional treatment to remove 

these gases from the exhaust stream. 

– Point-of-use (POU) abatement may be necessary in fabs where house scrubber 

infrastructure is not sufficient to abate the HF/F2 generated. 

– Coated stainless steel ductwork may be required. 

– Little information is publicly available on retrofits to non-Applied Materials tools. 

• Typical Remote Plasma Required Utilities 

Argon, NF3, or other PFC, electricity, process cooling water (PCW), toxic gas monitoring 

for NF3. 

• Reported Results 

PFC Utilization Efficiency (%) 

% PFC Emissions Reduction 

From Baseline Process 

NF3 >95–99 >15–99 

C3F8 >95 >35 

• Byproducts 

Remote cleans converts NF3 and other PFC into F+ ions and radicals. Units generate 

significant emissions of F2 and HF that must be abated. When using NF3 to clean carboncontaining low-k chambers, a small amount of CF4 is generated. No information is available 

on byproducts when using PFCs other than NF3 as input gas. 

• Cost 

Contact suppliers for cost information. 

• Remote Plasma Unit Manufacturers or Integration Specialists 

– New Power Plasma Co., Ltd. produces remote high-density plasma generators that 

decompose NF3 or C3F8 for CVD chamber cleaning. http://newpower.co.kr. 

– MKS Instruments, Inc. produces the ASTRON family of integrated remote plasma 

sources with flow rates of 2.0 slm up to 15 slm for semiconductor and flat panel CVD 

chamber cleaning. In addition to NF3, ASTRON hf-s series generators can dissociate 

alternative PFC gases such as C2F6, C3F8, CF4, or SF6. http://www.mksinst.com/ 

PRG1.html. 
25 

ISMI Technology Transfer #05104693A-ENG 

– LegacyTek offers a remote clean retrofit integration package to Applied Materials 

P5000 DxL and Centura DxZ 200 mm chambers; they are currently seeking beta 

partners to integrate remote cleans on Novellus tools. The LegacyTek upgrade package 

includes an MKS Instruments Astron or Astron-I remote plasma unit, integration 

package, installation and process startup. http://legacytek.com/index.htm. 

• Recent Publications 

L. Mendicino, P. T. Brown, S. Filipiak, C. Nauert, H. Estep, M. Fletcher, A. Atherton, and 

T. Nowak, “Fab Impacts of Implementation of Remote Clean for CVD Chamber Clean,” 

Proceedings of the SEMICON Southwest – A Partnership for PFC Emissions Reduction 

Workshop, oral paper #6 (2001). 

W. Worth, “Evaluation of Applied Material's Remote Clean Technology for Chamber 

Cleans and its Impact on a Fab’s Wastewater Treatment Facilities,” Proceedings of the 

8th ISESH Conference, paper 20.3C.3, ECSv2002-15, p. 127, 2001. 

S. Bailey, M. Goulding, L. Tousignant, L. Zazzera, and S. Shao, “Evaluation of an MKS 

ASTRONex and C3F8 for Remote Plasma Chamber Clean,” Proceedings of the 

SEMICON West 2002 STS Symposium, session 104, paper #2, 2002. 

ECS v2002-15, p. 144. 

G. Loh, Y. Osaki, and M. Mocella, “Remote Plasma Chamber Cleaning with the MKS 

ASTRONex Unit,” Proceedings of the 11th ISESH Conference, PFC paper #4, 2004. 

• References 

Information on remote cleans provided by Laura Mendicino of Freescale, Wang-Keun Kim 

of Samsung, and Chris Lewis of LegacyTek. Additional information obtained from websites 

of New Power Plasma Co. and MKS Instruments, Inc. 

A.4 Alternative Chemistry 

Alternative chemistry, or chemical substitution, is the use of chemicals with lower global 

warming potential (GWP) or no GWP as alternatives to PFCs. Alternative chemistry also 

includes high GWP gases that are more efficiently used in plasma processes, resulting in an 

overall greenhouse gas emissions reduction. 

• Technology Status 

In research and development and commercially available. 

• Pros 

– Alternative chemistries reduce total PFC emissions. 

– Drop-in chamber clean alternatives can be implemented with little to no additional cost 

and do not require additional ESH measures to be installed. 

– Alternative chemistries may also provide process benefits. 

– Implementing alternative chemistries can result in decreased gas consumption and 

improved COO. 
26 

Technology Transfer #05104693A-ENG ISMI 

• Cons 

– Implementing an alternative chemistry may require process re-qualification, especially 

for etch processes where the wafer is affected. 

– Certain alternatives increase ESH risk and require additional engineering controls. 

A.4.1 Chamber Clean Alternatives 

a) Hexafluoroethane (C2F6) for PECVD Chamber Cleans 

CF4 was the original POR for cleaning certain 150 mm PECVD process chambers. CF4

utilization efficiency in chamber cleans is reported as 0.2. One semiconductor company has 

reported replacing CF4 with hexafluoroethane (C2F6), resulting in a >57% emissions 

reduction due to decreased input gas consumption and more efficient PFC utilization. 

• Applicability and Status 

≤150 mm and 200 mm CVD chamber clean. Commercially available and currently in 

use. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of gas input (%) 

(mass/mass) 

% PFC Emissions 

Reduction from Baseline 

C2F6 Process 

C2F6 17–24 11–13 (CF4) >57 

• Cost 

No cost to implement unless process re-qualification required. 

• Pros 

– Significantly reduced PFC emissions from CVD chamber cleans. 

• Cons 

– May require process re-qualification. 

– Other alternative chemistries may results in greater PFC emissions reductions. 

• Recent Publications 

N/A 

• References 

Information received from an SIA member company. 
27 

ISMI Technology Transfer #05104693A-ENG 

b) Octofluoropropane (C3F8) for PECVD Chamber Cleans 

C2F6 was the original POR used to clean the majority of 150 mm and early 200 mm PECVD 

process chambers. Industry members are using octofluoropropane (C3F8) as an alternative to 

C2F6. C3F8 has a higher destruction removal efficiency (DRE) compared to C2F6 that can 

result in decreased gas consumption and emissions. Recent process optimization has resulted 

in decreased CF4 byproduct by optimizing the C3F8/O2 ratio. 

• Applicability and Status 

≤150 mm and 200 mm CVD chamber cleans. Commercially available and currently in 

use as a retrofit in manufacturing fabs. Novellus has developed C3F8 chamber clean 

PORs for Novellus Concept One and Concept Two SiN, SiON, SiO, and TEOS 

processes. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

C3F8 30–60 12–30 (CF4) 12–70 

• Cost 

No cost to implement unless process re-qualification required. Process results in a 

decreased COO of 20–65%. 

• Pros 

– No capital cost drop-in replacement. 

– Equivalent clean times. 

– Reduced PFC emissions from CVD chamber cleans. 

– Reduced COO. 

• Cons 

– May require process requalification. 

– Can result in significant CF4 byproducts. 

– Other alternative chemistries may result in greater PFC emission reductions. 

• Recent Publications 

S. Kesari, T. Bach, L. Tousignant, W. Reagen, and L. Zazzera, “Process Optimization 

and PFC Emission Reduction Using C3F8 Chamber Clean Processes in Applied 

Materials P-5000 PECVD Tools,” 2nd International Symposium on Environmental 

Issues with Materials and Processes for Electronics and Semiconductor Industries, 

Electrochem. Soc. Proceedings, L. Mendicino, Editor, 1999. 

• References 

Information received from SIA member companies including Bronwyn Pierce of HP. 
28 

Technology Transfer #05104693A-ENG ISMI 

c) Octofluorocyclobutane (c-C4F8) for PECVD Chamber Cleans 

c-C4F8 is being used to replace C2F6 and other fluorocarbon chamber clean chemistries. 

c-C4F8 dissociates more clean gas when compared to C2F6 and certain other fluorocarbon 

chemistries. Clean process uses more O2, but reduces CF4 formation. 

• Applicability and Status 

≤150 mm and 200 mm CVD chamber clean. Commercially available and currently in 

use as a retrofit in manufacturing fabs. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

c-C4F8 70–90 4–11 (CF4) 50–85 

• Cost 

No/low cost to implement unless process re-qualification required. Existing 

perfluorocarbon gas line can be used; mass flow controller (MFC) size may need to be 

reduced due to much lower c-C4F8 gas flow. 

• Pros 

– Drop-in replacement resulting in reduced PECVD chamber clean PFC emissions. 

– 20–75% decrease in COO due to decreased gas requirements. 

• Cons 

– May require process re-qualification. 

– Generates CF4 byproduct. 

– Other alternatives may result in greater PFC emission reductions. 

• Recent Publications 

E.M. Chan, G. Loh, and C.C. Allgood, “Process Optimization and Perfluorocompound 

(PFC) Emission Reduction Using a c-C4F8 Chamber Cleaning Process on a 

Novellus Concept 1 Dielectric Plasma Enhanced Chemical Vapor Deposition 

(PECVD) Tool,” IEEE Transactions on Semiconductor Manufacturing, 17, p.497, 

2004. 

K. Avala, L. Liu, D. Brindza, G. Loh, and S.A. Moiyadi, “Reduced Perfluorocompound 

(PFC) Emissions and Gas Consumption Using a c-C4F8-based Plasma Enhanced 

Chemical Vapor Deposition (PECVD) Chamber Clean Chemistry,” IEEE 

Transactions on Semiconductor Manufacturing, 17, p.504, 2004. 

C. Allgood, M. Mocella, H. Chae, and H. Sawin, “Evaluation of Octafluorocyclobutane 

as a Chamber Clean Gas in a Silicon Dioxide Plasma Enhanced Chemical Vapor 

Deposition (PECVD) Reactor,” J. Electrochem. Soc., 150, G122, 2003. 
29 

ISMI Technology Transfer #05104693A-ENG 

C.H. Oh, N.-E. Lee, J.H. Kim, G.Y. Yeom, S.S. Yoon, and T.K. Kwon, “Effect of 

N-containing Additive Gases on Global Warming Gas Emission During Remote 

Plasma Cleaning Process of Silicon Nitride Plasma Enhanced Chemical Vapor 

Deposition (PECVD) Chamber Using C4F8/O2/Ar Chemistry,” Surface and 

Coatings Technology, 171, p.267, 2003. 

A. Evans, L. Nevala, M. Sledz, and C.C. Allgood, “Advances in Reducing 

Perfluorocompound (PFC) Emissions and Gas Costs: Qualification of c-C4F8

Chamber Clean in a Novellus Concept-2 Chemical Vapor Deposition (CVD) Tool,” 

Proceedings of the 9th International Semiconductor ESH Conference, PFC Session 

A, Paper #1, 2002. 

A. Evans, L. Nevala, and C. Allgood, “Advances in Reducing Perfluorocompound 

(PFC) Emissions and Gas Costs: Qualification and Implementation of c-C4F8

Chamber Clean Gas in a Novellus Concept-2 Chemical Vapor Deposition (CVD) 

Tool,” Proceedings of the SEMICON Southwest PFC Seminar, Session 3, Paper 3, 

2002. 

• References 

Information received from an SIA member company, Francesca Illuzzi of 

STMicroelectronics, and Gary Loh of DuPont. 

Gary Loh 

Gary.loh@usa.dupont.com

304-999-4971 

d) Octafluorotetrahydrofuran (C4F8O) for PECVD Chamber Cleans 

C4F8O is currently being used to replace perfluorocarbons such as C2F6 and C3F8 in PECVD 

chamber cleans. C4F8O is an alternative chamber clean chemistry with higher DRE, 

resulting in reduced gas consumption. Higher DRE and reduced consumption lead to 

reduced PFC emissions and lower COO. 

• Applicability and Status 

≤150 mm and 200 mm CVD chamber clean. Commercially available and currently in 

use as a retrofit in manufacturing fabs. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

C4F8O 85–90 10–20 (CF4) 

4 (C3F8) 70–90 

• Cost 

No cost to implement unless process re-qualification required. Special attention is 

required for monitoring corrosion effects of reactor parts. Weight monitoring is 

recommended for cylinder fill information. Low-pressure regulators at gas cabinet are 

recommended. 
30 

Technology Transfer #05104693A-ENG ISMI 

• Pros 

– Drop-in replacement with significantly reduced PFC emissions from CVD chamber 

cleans. 

– 20–50% reduction in COO. 

• Cons 

– May require process re-qualification. 

– Monitoring of parts for corrosion effects is necessary. 

– Generates CF4 byproduct, although at a lower rate than some alternatives. 

• Recent Publications 

K.J. Kim, C.H. Oh, N.-E. Lee, J.H. Kim, J.W. Bae, G.Y. Yeom, and S.S. Yoon, “Global 

Warming Gas Emission During Plasma Cleaning Process of Silicon Nitride Using 

c-C4F8O Feed Gas with Additive N2,” Han'guk Pyomyon Konghak Hoechi, 34, 403, 

2001; Chem. Abstr., 138, 94335, 2003. 

C.H. Oh, N.-E. Lee, J.H. Kim, G.Y. Yeom, S.S. Yoon, and T.K. Kwon, “Increase in 

Cleaning Rate and Reduction in Global Warming Effect During C4F8O/O2 Remote 

Plasma Cleaning of Silicon Nitride by Adding NO and N2O,” Thin Solid Films, 

435, 264, 2003. 

D. Harman, J. Flood, and E. Frendberg, “Evaluation of C4F8O as an Alternative 

Material in Chemical Vapor Deposition (CVD) Chamber Cleaning,” Proceedings of 

the 9th International Semiconductor ESH Conference, PFC Session A, Paper #4, 

2002. 

D. Harman, J. Flood, and E. Frendberg, “Evaluation of C4F8O for Chemical Vapor 

Deposition (CVD) Chamber Cleans,” Proceedings of the SEMICON West 2002 STS 

Symposium, Session 104, Paper #3, 2002. 

J.H. Kim, J.W. Bae, C.H. Oh, K.J. Kim, N.E. Lee, and G.Y. Yeom, “C4F8O/O2/N-based 

Additive Gases for Silicon Nitride Plasma Enhanced Chemical Vapor Deposition 

(PECVD) Chamber Cleaning with Low Global Warming Potentials,” Jpn. J. Appl. 

Phys., 41, p. 6570, 2002. 

R. Van San, S. Kesari, and L. Zazzera, “Evaluation and Qualification of C4F8O as an 

in situ Cleaning Gas for Plasma Enhanced Chemical Vapor Deposition (PECVD) 

Tools,” SEMI Conference Proceedings – A Partnership for PFC Emission 

Reduction, SEMICON Southwest, October 2000. 

• References 

Information received from Harry Thewissen of Philips Semiconductor, Francesca 

Illuzzi of STMicroelectronics, and an SIA member company. 
31 

ISMI Technology Transfer #05104693A-ENG 

e) Nitrogen Trifluoride (NF3) for in situ PECVD Chamber Cleans 

NF3 is currently being used in manufacturing fabs as a replacement for in situ 

perfluorocarbon PECVD chamber cleans. Additionally, Novellus is using dilute in situ NF3

cleans for their advanced 200 mm and 300 mm tools. NF3 has a high DRE when used in 

plasma; moreover, unlike fluorocarbons, NF3 does not generate CF4 byproduct unless it is 

used to clean carbon-containing films. When compared to C2F6, NF3 cleans require less 

clean gas and result in faster clean times. 

• Applicability and Status 

Commercially available and currently in use as a retrofit for ≤150 mm and 200 mm 

CVD chamber clean. POR on advanced 200 mm and 300 mm Novellus tools. NF3 is 

also used for thin film transistor liquid crystal display chamber cleans. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

NF3 60–80 

0–4 (CF4) 

Depending on carbon 

content of film removed 

20–90 

• Cost 

Toxic gas monitoring and additional safety measures may be necessary. Upgraded 

exhaust duct and point-of-use fluorine abatement may be needed. 

• Pros 

– Significantly reduced PFC emissions from CVD chamber cleans. 

– Unlike fluorocarbons, NF3 does not generate CF4 byproduct unless it is used to 

clean carbon-containing films. 

• Cons 

– In situ NF3 is not a drop-in replacement; NF3 is an oxidizer and has a lower LD50 

than C2F6. 

– Toxic gas monitoring may be necessary. 

– Clean process may result in higher emissions of HF and F2 as well as NOx. 

– ESH controls such as local scrubbing may be required; additionally, one 

semiconductor manufacturer recommended installation of coated stainless steel 

exhaust duct. 

– Monitoring of parts for corrosion effects is necessary. 

– May require process requalification. 

• References 

Information received from SIA member companies. 
32 

Technology Transfer #05104693A-ENG ISMI 

f) Carbonyl Fluoride (COF2) for PECVD Chamber Cleans 

COF2 is a toxic gas with low GWP and no ozone depletion potential. From 1998–2002, 

Japan’s Research Institute of Innovation Technology for the Earth undertook an effort to 

identify alternative chamber clean chemistries, eventually recommending COF2 as a 

replacement gas. With a GWP of 1, COF2 has a much lower global warming potential than 

PFCs used for chamber cleans. Although COF2 is toxic, it is easily removed from the 

exhaust stream by water scrubbing. When used in plasma, a small amount of CF4 byproduct 

is produced. Recent efforts in Japan have focused on evaluating COF2 in manufacturing 

applications. 

• Applicability 

≤150 mm and 200 mm CVD chamber clean. Currently undergoing evaluation in 

manufacturing fabs in Japan. 

• Reported Results 

At the 12th ISESH Conference held in 2005, Japan Electronics and Information 

Technologies Industries Association members presented results of COF2 evaluations as 

alternatives to C2F6 and C3F8 cleans in manufacturing environments. On a 200 mm 

Novellus Concept Two running PETEOS. Panasonic reports that COF2 cleans resulted 

in a 96% PFC emission reduction and equivalent cleaning performance when compared 

to C2F6 with no adverse affect to the tool. On a Novellus Concept One depositing 

silicon nitride film on eighty thousand 125 mm and 150 mm bipolar wafers, Sanyo 

reported a 97% PFC emission reduction and no technical difficulties when compared to 

the baseline C3F8 process. CF4 byproduct was between 1.2–1.8%. 

• Cost 

Although not listed in conference proceedings, a gas cost of 20,000Yen/kg was 

mentioned at the 12th Annual ISESH Conference. Additional ESH controls are required. 

Incompatibilities may require re-piping process gases into the chamber. POU scrubbing 

may be required. 

• Pros 

– 96–97% reduction in PE-CVD chamber clean PFC emissions. 

– Faster clean times. 

• Cons 

– High gas cost. 

– Additional ESH controls required. 

– Sanyo notes that, because reactivity with NH3 is high, separate gas lines into the 

chamber must be installed to prevent inadvertent mixing. 

– May require process requalification. 
33 

ISMI Technology Transfer #05104693A-ENG 

• References 

M. Sakamura, T. Minegishi, and M. Yomoda, “Evaluation of COF2 in Mass Production 

Line,” 12th Annual ISESH Conference, June, 2005. 

S. Ueda, K. Takahashi, T. Matsubara, and H. Nikou, “Investigation of an Alternative 

Gas COF2 Application for Chemical Vapor Deposition (CVD) Chamber Cleaning 

Process,” 12th Annual ISESH Conference, June, 2005. 

Y. Mitsui, “Alternative Gas for Chemical Vapor Deposition (CVD) Cleaning COF2,” 

12th Annual ISESH Conference, June, 2005. 

g) Fluorine (F2) for CVD Chamber Cleaning 

F2 has been discussed as a possible alternative to PFCs for CVD chamber cleaning but had 

been discarded as a serious alternative in the past due to the ESH risks associated with 

transport, storage, and use of high-pressure F2 cylinders. BOC-Edwards and Fluorine on 

Call, Ltd. have each developed onsite fluorine generators that convert anhydrous HF into F2

by electrolysis. After the F2 is generated, it is purified to remove residual HF and other 

contaminants. It can then be fed into PECVD chambers for plasma-enhanced in situ cleans. 

Samsung reports evaluating in situ generated F2 to replace NF3 for low-pressure chemical 

vapor deposition (LPCVD) or CVD chamber cleaning on 300 mm tools. This evaluation is 

in the research and development stage. 

• Applicability 

≤150 mm, 200 mm, 300 mm and thin film transistor liquid crystal display CVD 

chamber cleans. Processes are currently in R&D. 

• Cost 

Contact suppliers for cost of on site F2 generators. Although additional engineering 

controls are required, Samsung anticipates that replacing NF3 with onsite generated 

fluorine will result in 20% cost savings due to reduced chemical and operational costs. 

• Pros 

– While anhydrous HF is toxic and corrosive and F2 is highly toxic and a strong 

oxidizer, neither of these gases are global warming gases. 

– No PFC emissions will be generated during CVD chamber cleans unless F2 is used 

to remove carbon-containing films. 

• Cons 

– Fluorine generation and use poses additional ESH risks that must be addressed 

when designing installation site, piping, and generator system. 

– POU abatement may be required to abate F2 emissions from chamber clean. 
34 

Technology Transfer #05104693A-ENG ISMI 

• Recent Publications 

S. Siegele, D. Hage, and F. Siegele, “On-Site Generation of High Purity Fluorine (F2) 

as a Safe and Economical Alternative for Chemical Vapor Deposition (CVD) 

Chamber Cleaning,” FutureFab International, Issue 13, July, 2002.

Generation-F 80 Onsite Fluorine Generator, BOC-Edwards Product Data Sheet. 

• References 

Information received from Wang-Kim Keun of Samsung, Chris Case of BOC-Edwards, 

and Dan Hage of Fluorine on Call, Ltd. 

Chris Case 

Chris.Case@bocedwards.com

908-771-6409 

Dan Hage 

dhage@focltd.com

512-329-8866 

A.4.2 Alternative Etch Chemistries 

While replacement of high GWP gases with lower or non-GWP gases is generally preferable, it 

has not proven feasible in most plasma etch applications. Processing requirements for high 

aspect ratio plasma etching continue to become more stringent, requiring both fluorine to etch 

and the right carbon to fluorine ratio to ensure anisotropic etching. A significant amount or 

research has been done on alternative etchants such as iodofluorocarbons, hydrofluorocarbons, 

and unsaturated fluorocarbons; however, many of these chemicals are not viable alternative 

etchants in a manufacturing environment due to excess polymerization, lack of etch selectivity, 

difficulties in delivering gases to the process chamber, and potential increased employee 

exposure risks. 

One alternative that is being implemented in manufacturing is C4F6, which is being used as a 

dielectric etch gas for advanced ULSI integration, replacing CF4, CHF3, and C4F8. 

• Applicability 

C4F6 is being used in advanced 200 mm and 300 mm manufacturing fabs for oxide and 

low-k etching where high selectivity for silicon is required in the presence of nitride or other 

films with high aspect ratios, thinner resists and less etch resistant resists. 

• Reported Results 

Replacement 

Chemistry 

Utilization 

Efficiency (%) 

PFC Byproduct Generation 

as % of Gas Input (%) 

(mass/mass) 

% PFC Emissions 

Reduction From Baseline 

C2F6 Process 

C4F6 > 95 5–10 (CF4) >90 in some cases 

• Pros 

– C4F6 is a process enabling technology for CD control and etch selectivity and, with an 

atmospheric lifetime <1 year and utilization efficiency >95%, PFC emission reductions 

>90% can be achieved. 
35 

ISMI Technology Transfer #05104693A-ENG 

– C4F6 can be implemented as an alternative chemistry using existing hardware and gas 

lines; however, toxic gas monitoring may be needed. 

• Cons 

– As is the case with all higher molecular weight fluorocarbon compounds used in plasma 

processes, some CF4 byproduct is formed and emitted. 

• Recent Publications 

S. Karecki, L. Pruette, R. Reif, T. Sparks, L. Beu, and V. Vartanian, “Use of Novel 

Hydrofluorocarbon and Iodofluorocarbon Chemistries for a High Aspect Ratio Via Etch 

in a High Density Plasma Etch Tool,” Journal of the Electrochemical Society, Vol. 145, 

No. 12, December 1998. 

S. Karecki, R. Chatterjee, L. Pruette, R. Reif, T. Sparks, L. Beu, and V. Vartanian, 

“Evaluation of Pentafluoroethane and 1,1-Difluoroethane for a Dielectric Etch 

Application in a High Density Plasma Etch Tool,” Jpn. J. Appl. Phys., 39, Part 1 (7B), 

4666–4686, July 2000. 

R. Chatterjee, S. Karecki, R. Reif, T. Sparks, V. Vartanian, B. Goolsby, “Evaluation of 

Hexafluorobenzene as an Environmentally Benign Dielectric Etch Chemistry,” Journal 

of The Electrochemical Society, Volume 148, Issue 12, pp. G721–G724, December 

2001. 

F. Fracassi, R. d'Agostino, E. Fornelli, F. Illuzzi, and T. Shirafuji, “SiO2 Etching with 

Perfluorobutadiene in a Dual Frequency Plasma Reactor,” Journal of Vacuum Science & 

Technology A: Vacuum, Surfaces, and Films, Volume 21, Issue 3, pp. 638–642, May 

2003. 

A.D. Johnson, R.G. Ridgeway, and P.J. Maroulis, “Reduction of Perfluorocompound (PFC) 

Emissions to the Environment Through Advances in Chemical Vapor Deposition (CVD) 

and Etch Processes,” IEEE Transactions on Semiconductor Manufacturing, 17, p. 491, 

November 2004. 

• References 

Information on C4F6 was provided by Ajay Somani of MIT, Laura Mendicino and Victor 

Vartanian of Freescale Semiconductor, and Robert Ridgeway of Air Products and 

Chemicals, Inc. 

Robert Ridgeway 

ridgewrg@airproducts.com

610-481-4436 
36 

Technology Transfer #05104693A-ENG ISMI 

A.5 Capture/Recovery 

A.5.1 Air Liquide PFC Capture and Recycle 

In 2003, Air Liquide installed a compact membrane capture and recirculation system for SF6 at a 

power IC manufacturer. The IC manufacturer uses SF6 as a blanket gas during IC testing. A 

mixture of 60% SF6 and 40% air is exhausted from the testers. The Air Liquide unit compresses 

the exhaust stream, which is then fed into two membrane separation units. Because the SF6 is 

being used as a blanket gas, not as a plasma etchant, byproducts requiring pre-treatment are not 

present in the exhaust stream. Air Liquide reports an 89% SF6 recovery rate at >99% purity. 

Recovered SF6 is fed back into the testers. 

• Project Status 

System is in operation and Air Liquide reported in 2004 that the system had paid for itself in 

related cost savings. 

• Applicability 

The Air Liquide membrane separation system has a modular design for a wide range of PFC 

flow rates. It appears to be most cost effective when used for specialized, single PFC, high 

volume processes. The lack of plasma and other process byproducts in this particular 

application makes capture-recovery relatively straightforward and cost effective. 

• Pros 

– Cost effective and environmentally preferred method for addressing emissions from 

clean, high volume, single PFC processes. 

• Cons 

– Centralized PFC capture/recovery has not been implemented in semiconductor 

manufacturing because it has been deemed too costly to implement due to pretreatment 

requirements and decreasing PFC concentrations over time in the exhaust. 

• References 

C-H Ly, R. Daniel, and C. Anderson, “Perfluorocompound (PFC) Emission Reduction Via 

Membrane Capture Processing in Semiconductor,” 11th Annual ISESH Conference, 

2004. 

A.6 Abatement 

A.6.1 PFC Abatement – POU Fueled Burner – Scrubber Units 

• General Technology Description 

Point-of-use fueled burner-scrubber units use a propane, methane, natural gas or hydrogen 

flame to destroy PFCs and other hazardous substances such as deposition precursors 

followed by a water scrubber, which may contain a base solution, to remove volatile acid 

gases from the exhaust stream. Burner-scrubber units are installed on the process tool 

exhaust line after the vacuum pump and, thus, the exhaust stream entering the unit contains a 

large amount of nitrogen (from pump purge and ballast) that can lower the combustion unit 
37 

ISMI Technology Transfer #05104693A-ENG 

temperature, thus, typically requiring the addition of oxygen to the reach flame temperatures 

high enough to destroy the carbon based PFCs and SF6. Burner-scrubber units can typically 

abate emissions from multiple process chambers. 

• Applicability 

Both CVD and etch effluents from ≤150 mm, 200 mm, and 300 mm process tools can be 

treated with the burner-scrubber units. 

• Pros 

– Commercially available from multiple suppliers 

– Technology that abates both etch and CVD chamber clean PFC emissions at ≥95% DRE 

and removes HF, generated as a result of burning PFCs, from the exhaust stream. 

– Fueled systems destroy F2, converting it into HF, and scrub the HF byproduct. 

– Units are capable of abating emissions from multiple process chambers. 

– Largest installed base of abatement systems in the industry. 

• Cons 

– Requires H2 or natural gas (NG) fuel. Generates HF liquid waste stream which may 

require further treatment before discharge. 

– May generate NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be limited, 

and either H2 or NG, which may not be installed as a service utility. 

• Manufacturers of Burner-Scrubber Units Without Detailed Information in this 

Appendix 

– ATTO Co, Ltd., produces modified Centrotherm abatement devices for the Korean 

market. http://atto.co.kr/2004e/product/pro_012_04.htm

– Global Standard Technology Co., Ltd., company produces modified DAS abatement 

systems for the Korean market. http://www.gst-in.com/contents/business/product/ 

product01/0111.asp

– UNI-SEM, Korean manufacturer of UN2000-A thermal oxidizer with wet scrubber 

using H2 as fuel. The footprint is 750 mm × 870 mm × 2262 mm. http://uni-sem.com/ 

html/pfcmain.html

a) BOC Edwards Thermal Processor Unit (TPU) 

• Description 

The TPU is a point-of-use abatement device, installed post-vacuum pump, which 

utilizes an inwardly fired combustor followed by a three-stage wet scrubber and using 

proprietary combustion methods to ensure maximum DRE of PFCs and process gases. 

The TPU operates in two modes: high fire and low fire. In high fire mode, higher flows 

of fuel and O2 are injected to abate PFCs (with communication between process 

equipment and the TPU). The footprint is 1300 mm × 625 mm × 1833 mm. Addition of 
38 

Technology Transfer #05104693A-ENG ISMI 

the scrubber water recirculation unit (WRU) increases width to ∼1600 mm. The unit is 

installed downstream of the vacuum pumps and can handle effluent from multiple 

chambers (up to four) with a maximum flow capacity of 200 slm. 

• Technology Status 

Commercially available. 

• Applicability 

Both CVD and etch effluents can be treated with the TPU. Tool can be installed as a 

retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm process 

tools. 

• Required Utilities 

Electricity, water (∼6 gpm), natural gas, N2, O2, acid waste drain, acid scrubbed 

exhaust, and general exhaust. Scrubber water consumption can be reduced to <1 gpm 

makeup water by installing the WRU. The WRU requires cooling water. 

• Reported Results 

DRE (%) 

PFC Maximum PFC Input Flow Rate (sccm) * # ^ 

NF3 6000# > 95 99.99 99 

SF6 12000# 90 to > 905 99.9 95 

C2F6 2500–10000* / 6400# 85 to > 95 99.9 95 

CHF3 6000# 90 99.99 99 

C4F8 6000# 95 99.9 99 

C3F8 6400# 99.9 99.9 95 

CF4 2000* / 6000# 90–96 93 90 

CH2F2 3300 mg/m3 * > 95* 

C5F8 900 mg/m3 * > 90* 

* Performance reported by semiconductor manufacturers 

# Supplier reported performance 

^ Supplier guaranteed 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs are CO2 and HF. HF is removed 

in the wet scrubber. NOx is emitted at ∼75 ppm/inlet while destroying CF4 due to high 

operating temperature. NF3 combustion results in formation of N2, HF, and NOx. One 

semiconductor manufacturer reports CO emissions at ∼50 mg/m3. 

• Cost of Technology (provided by supplier) 

$120,000 USD per unit. 
39 

ISMI Technology Transfer #05104693A-ENG 

• Cost of Ownership 

TPU requires replacement of seals, gaskets, and combustor (depends on process) as 

needed for annual PM. Consumable costs are variable and can range from ∼$4000–

$8000 USD annually. One semiconductor company noted high cost to operate mainly 

due to heavy maintenance and consumables. Typical annual facilities costs for operation 

of the TPU based on Fab Utility Cost Values for Cost of Ownership (COO) 

Calculations (SEMATECH, Technology Transfer #02034260A-TR) is ∼$8000 USD. 

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥93% DRE and removes HF, generated as a result of burning 

PFCs, from the exhaust stream. 

– Destroys F2 and removes the resulting HF. 

– Unit is capable of abating emissions from multiple process chambers. 

– Established technology with installed base of TPUs in multiple semiconductor 

facilities in the U.S., Europe, and Asia. 

• Cons 

– Requires NG, which may not be available as a service utility. 

– Generates HF liquid waste stream, which may require further treatment before 

discharge. 

– Abatement of CF4 and NF3 generates NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited, and NG, which may not be installed as a service utility. 

– Oxygen, which also may not be available as a service utility, or compressed dry air 

(CDA) may be necessary to abate CF4. 

• Contact 

Joe Van Gompel 

512-633-5105 

joe.vangompel@bocedwards.com

• References 

Information on the TPU was provided by SIA and ISMI member companies including 

Bronwyn Pierce of HP, a member of ESIA, and Francesca Illuzzi of 

STMicroelectronics, and by Joe Van Gompel of BOC-Edwards. 
40 

Technology Transfer #05104693A-ENG ISMI 

b) BOC Edwards Mini-TPU 

• Description 

The Mini-TPU is a point-of-use abatement device, installed post-vacuum pump, which 

utilizes an inwardly fired combustor followed by a three-stage wet scrubber and using 

proprietary combustion methods to ensure maximum DRE of PFCs and process gases. 

It is designed strictly to abate emissions from oxide etch and poly etch processes only 

and is not suitable for CVD. Maximum exhaust flow rate through the Mini-TPU is 

50 slm. The mini-TPU is not sold as a standalone unit but is incorporated with high 

efficiency vacuum pumps in a package called Zenith Etch that is designed for cost- and 

space-effective PFC abatement. The total footprint of abatement and pumps is 1300 mm 

× 625 mm × 1833 mm. 

• Technology Status 

Commercially available. 

• Applicability 

Oxide and poly etch effluents can be treated with the Mini-TPU. Tool can be installed 

as a retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm process 

tools. 

• Required Utilities 

Electricity, water, NG, N2, O2, acid waste drain, acid scrubbed exhaust, and general 

exhaust. 

• Supplier Reported Results 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 1000 >99 

SF6 1000 >99 

C4F8 1000 >99 

CH2F2 1000 >99 

C4F6 1000 >99 

C5F8 1000 >99 

CF4 1000 93 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs are CO2 and HF. HF is removed 

in the wet scrubber. NOx is negligible for all other PFCs except NF3, which realizes 

about 20% conversion to NOx of NF3 that actually makes it out of the process chamber 

and into the abatement device. 

• Cost of Technology (provided by supplier) 

Capital cost as low as $30,000 USD per inlet on etch processes. 
41 

ISMI Technology Transfer #05104693A-ENG 

• Cost of Ownership 

TPU requires replacement of seals, gaskets, and combustor (depends on process) as 

needed for annual PM. Consumable costs are typically <$4000 USD annually. Typical 

annual facilities costs for operation of the Mini-TPU based on Fab Utility Cost Values 

for Cost of Ownership (COO) Calculations (SEMATECH, Technology Transfer 

#02034260A-TR) is ∼$4000 USD. 

• Pros 

– Commercially available technology that abates oxide and poly etch emissions at 

≥93% DRE and removes HF, generated as a result of burning PFCs, from the 

exhaust stream. It also destroys F2 and removes the resulting HF. 

– Unit is capable of abating emissions from multiple process chambers. 

• Cons 

– Requires NG, which may not be available as a service utility. 

– Generates HF liquid waste stream, which may require further treatment before 

discharge. 

– Abatement of NF3 generates NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited; and NG, which may not be installed as a service utility. 

– May require oxygen or compressed dray air (CDA) to abate CF4, which may not be 

available as a service utility. 

• Contact 

Joe Van Gompel 

512-633-5105 

joe.vangompel@bocedwards.com

• References 

Information on the mini-TPU was provided by Joe Van Gompel of BOC Edwards. 

c) Centrotherm CT-BW Burner Washer 

• Description 

Centrotherm has developed a modular abatement system whose components can be 

specified based on the specific requirements of the process being abated. The 

Centrotherm CT-BW contains a cone-shaped burner chamber and a separate high 

efficiency wet scrubber section. The CT-BW is sold as a single system or a 100% 

redundancy dual system. The footprint ranges from 650 mm × 800 mm × 1850 mm to 

800 mm × 1300 mm × 2000 mm. The unit can handle effluent from multiple chambers 

with a maximum flow rate of 600 slm. 

• Technology Status 

Commercially available. 
42 

Technology Transfer #05104693A-ENG ISMI 

• Applicability 

Both CVD and etch effluents can be treated with the CT-BW. Tool can be installed as a 

retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm process 

tools. 

• Required Utilities 

Electricity, cooling water (∼7 slm), O2, NG, or hydrogen, scrubber water (1.5 slm 

makeup water), KOH, or NaOH for scrubber. 

• Supplier Reported Results (no semiconductor manufacturer provided data 

available) 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 10,000 99 

SF6 7000 99 

C2F6 7000 99 

CHF3 99 

C4F8 99 

CF4 7000 84–95 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs include CO2 and HF. Final rinse 

from scrubber contains KF or NaF. NF3 combustion results in formation of N2, HF, and 

NOx. Final scrubber rinse contains KF, KNO2, and KNO3. NOx formation depends on 

set up of the system and flow of N2 vs. the set-up of the flame. 

• Cost of Technology (provided by supplier) 

$95,000–$110,000 USD per unit. 

• Cost of Ownership 

No information provided.

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥95% DRE and removes HF, generated as a result of burning 

PFCs, from the exhaust stream. 

– Unit is capable of abating emissions from multiple process chambers. 

– Modular design with 100% redundancy capability. 

– Newer burner-washer technology than CT-FLM with installed base of CT-BWs in 

semiconductor facilities in Europe and Korea. 

– Centrotherm’s Asia partner is ATTO, which sells a modified device adapted to the 

Korean market. 
43 

ISMI Technology Transfer #05104693A-ENG 

• Cons 

– Requires H2 or NG. 

– Generates HF liquid waste stream which may require further treatment before 

discharge; however, Centrotherm has developed an HF treatment system. 

– May generate NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited, and either H2 or NG, which may not be installed as a service utility. 

• Contact 

Volker Kinzig 

Volker.Kinzig@centrotherm.de

Phone 0049-7344-918-1801 

• References 

Information provided by Volker Kinzig of Centrotherm. 

d) Centrotherm FLM (CT-FLM) Flawamat Burner-Scrubber 

• Description 

The CT-FLM is a point-of-use abatement device, installed post-vacuum pump, in which 

effluent enters an inner tube where it is burned. Effluent from the burner chamber 

leaves the bottom of the burner through an outer tube where it is washed from the top 

by a spray nozzle. The CT-FLM is sold as a single system. The footprint is from 

650 mm × 800 mm × 1850 mm. The unit is installed downstream of the vacuum pumps 

and can handle effluent from multiple chambers with a maximum flow capacity of 

300 slm. 

• Technology Status 

Commercially available. 

• Applicability 

Both CVD and etch effluents can be treated with the CT-FLM. Tool can be installed as 

a retrofit or during new tool installation. 

• Required Utilities 

Electricity, water, oxygen, NG or hydrogen, KOH- or NaOH-solution for scrubber, HF 

waste drain. 
44 

Technology Transfer #05104693A-ENG ISMI 

• Reported Results 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 > 95–99 

SF6 3000# > 95* / 99# 

C2F6 3000# > 90–98* 

CHF3 98* 

C4F8 99* 

C3F8 98* 

CF4 3000# 90–95* 

*Performance reported by semiconductor manufacturer(s) 

# Supplier reported performance 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs include CO2 and HF. Final rinse 

from scrubber contains KF or NaF. NF3 combustion results in formation of N2, HF, and 

NOx. Final scrubber rinse contains KF, KNO2, and KNO3. NOx formation depends on 

set up of the system and flow of N2 vs. the set-up of the flame. 

• Cost of Technology (provided by supplier) 

$95,000–$110,000 USD per unit. 

• Cost of Ownership 

FLM requires regular cleaning of internal parts, resulting in periodic cleaning costs and 

maintenance effort. 

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥95% DRE and removes HF, generated as a result of burning 

PFCs, from the exhaust stream. 

– Unit is capable of abating emissions from multiple process chambers. 

– Established technology with installed base of CT-FLMs in multiple semiconductor 

facilities in Europe and Korea. 

– Centrotherm’s Asia partner is ATTO, which sells a modified device adapted to the 

Korean market. 

• Cons 

– Requires H2 or NG. 

– Generates HF liquid waste stream which may require further treatment before 

discharge; however, Centrotherm has developed an HF treatment system. 

– May generate NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited, and either H2 or NG, which may not be installed as a service utility. 
45 

ISMI Technology Transfer #05104693A-ENG 

• Contact 

Volker Kinzig 

Volker.Kinzig@centrotherm.de

Phone 0049-7344-918-1801 

• References 

Information on the FLM was provided by Gabriele Fetzer of Philips Semiconductor,

Wang-Keun Kim of Samsung, Francesca Illuzzi of STMicroelectronics, and Volker 

Kinzig of Centrotherm. 

e) DAS ESCAPE-INLINE 

• Description 

The ESCAPE INLINE is a point-of-use abatement device, installed post-vacuum pump, 

in which effluent from up to four process chambers enters a combustion chamber. 

Toxic, flammable, or pyrophoric compounds as well as PFCs are decomposed in the 

flame by pyrolysis, reduction and oxidation reactions. Directly after the combustion 

chamber the gas is quenched rapidly and passed through a wet scrubber column where 

acidic compounds and particulate matter are retained. The scrubber liquid is recirculated and automatically exchanged without interruption of the abatement process. 

The footprint is 688 mm × 830 mm × 2070 mm (standard version) and has a maximum 

flow capacity of 200 slm. 

• Technology Status 

Commercially available with >1200 units installed. 

• Applicability 

Both CVD and etch effluents can be treated with the ESCAPE-INLINE. Abatement 

device can be installed as a retrofit or during new tool installation. 

• Required Utilities 

NG, LPG, or hydrogen for fuel; electricity, water, oxygen, CDA, cooling water, N2. 

KOH- or NaOH-solution for scrubber, HF waste drain. 

• Reported Results 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 6000# > 95* 99# 

SF6 3000# > 95* 95# 

C2F6 3000# > 90* 95# 

CHF3 6000# 99# 

CH2F2 10,000# 99# 

C3F8 2500# 99# 

CF4 5000# 90* 95# 

*Performance reported by semiconductor manufacturer(s) 

# Supplier reported performance 
46 

Technology Transfer #05104693A-ENG ISMI 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs include CO2 and HF. According 

to supplier, NOx levels are lower than required by national clean air standards (specific 

country and standards not cited). 

• Cost of Technology (per unit) 

Not provided. Contact supplier to obtain a quote. 

• Cost of Ownership 

Consumables are required for proper operation and maintenance but specific 

information not available. 

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥95% DRE and removes HF, generated as a result of burning 

PFCs, from the exhaust stream. 

– Unit is capable of abating emissions from multiple process chambers. 

– Established technology with installed base in multiple semiconductor facilities. 

• Cons 

– Requires fuel. 

– Generates HF liquid waste stream, which may require further treatment before 

discharge. 

– May generate NOx. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited, and either H2, LPG, or NG, which may not be installed as a service utility. 

• Contact 

Dr. A. Frenzel 

frenzel@das-europe.de

Phone 49-351-871 8634 

• References 

Information provided by Francesca Illuzzi of STMicroelectronics and A. Frenzel of 

DAS. 

S-N Li, et al, “FTIR Spectrometers Measure Scrubber Efficiencies,” Solid State 

Technology, July 2002. 
47 

ISMI Technology Transfer #05104693A-ENG 

f) Ecosys Marathon 8500 

• Description 

The Ecosys Marathon 8500 is a point-of-use abatement device, installed post-vacuum 

pump, which utilizes a staged natural gas or liquid propane gas combustor followed by 

a wet scrubber to ensure maximum DRE of PFCs and process gases. The footprint is 

1168 mm × 637 mm × 2261 mm. The unit is installed downstream of the vacuum 

pumps and can handle effluent from multiple process chambers and tools with a 

maximum flow capacity of 700 slm. 

• Technology Status 

Commercially available. 

• Applicability 

Both CVD and etch effluents can be treated with the Marathon 8500. Device can be 

installed as a retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm 

process tools. 

• Required Utilities 

208/220 VAC; 10 A, 2 kW; 0.3–1.25 gpm fresh water; 2–15 gpm cooling water; 

70 scfm CDA; 35 scfm N2; 1.3–3.5 scfm natural gas, acid waste drain, 120 scfm 

exhaust. 

• Supplier Reported Results (no semiconductor manufacturer provided data 

available) 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 4500 99 

SF6 5000 99 

C2F6

> 2400 

(not tested at higher flow) > 99.9 

C3F8

> 3000 

(not test at higher flow) > 99.9 

CF4 8000 97 

CF4 4000 98 

CF4 2000 99 

• Byproducts 

Byproducts of combustion for carbon-containing PFCs are CO2 and HF. HF is removed 

in the wet scrubber. CO and NOx production is below 500 lbs/year/device. 

• Cost of Technology (provided by supplier) 

$ 120,000 USD per unit. 

• Cost of Ownership 

Ecosys indicates cost of parts and labor on an annual basis to be $3700 and COO on an 

annual basis is $5300. 
48 

Technology Transfer #05104693A-ENG ISMI 

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥97% DRE and removes HF, generated as a result of burning 

PFCs, from the exhaust stream. 

– Unit is capable of abating emissions from multiple process chambers and multiple 

tools. 

• Cons 

– Requires NG or LPG, which may not be available as a service utility. 

– Generates HF liquid waste stream, which may require further treatment before 

discharge. 

– Abatement generates CO and NOx; the ESH impact of these needs to be assessed. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited, and NG or LPG, which may not be installed as a service utility. 

• Contact 

Sebastien Raoux, Ecosys 

408-719-4668 

Sebastien_Raoux@metrontech.com

• References 

Information on the Ecosys Marathon 8500 was provided by Sebastien Raoux of Ecosys. 

A.6.2 PFC Abatement – POU Catalytic–Scrubber Units 

• General Technology Description 

Point-of-use catalytic-scrubber units use a catalyst to promote the destruction of PFCs and 

process gases at lower activation energies than would otherwise be needed. Catalytic 

systems operate at a lower temperature than other PFC abatement systems and do not 

require fuel. A water scrubber typically follows the catalytic reactor to remove HF 

byproduct from the exhaust stream. Catalytic-scrubber units are installed on the process tool 

exhaust line after the vacuum pump and, thus, the exhaust stream entering the unit contains a 

large amount of nitrogen. Catalytic-scrubber units can typically abate emissions from 

multiple process chambers. 

• Applicability 

Both CVD and etch effluents from ≤150 mm, 200 mm, and 300 mm process tools can be 

treated with the burner-scrubber units. 

• Pros 

– Catalytic-scrubber units operate at lower temperatures than other PFC abatement 

systems and do not utilize a fueled flame. 
49 

ISMI Technology Transfer #05104693A-ENG 

• Cons 

– Pre-scrubbers are required to prevent catalyst poisoning. 

– Catalyst has a limited lifetime and must be replaced periodically. 

– Cost of ownership needs to be evaluated. 

a) Ecosys Trinity 

• Description 

The Ecosys Trinity is a point-of-use abatement device, installed post-vacuum pump, 

which uses state of the art catalytic methods to ensure maximum DRE of PFCs and 

process gases. The etch exhaust stream first passes through a water scrubber where 

water soluble gases and particles are removed, then into the catalytic reactor where 

PFCs are reacted to form HF, and finally through a second water scrubber to remove the 

HF. The Trinity has a 686 mm × 914 mm × 2006 mm footprint and can handle multiple 

chambers with an flow capacity of 200 slm. 

• Technology Status 

Commercially available. 

• Applicability 

The Trinity can abate etch emissions. Tool can be installed as a retrofit or during new 

tool installation on ≤150 mm, 200 mm, and 300 mm process tools. 

• Required Utilities: 

Water, air, electricity, acid waste drain, process gas exhaust. 

• Supplier Reported Results 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

C3F8 1000 99 

* Maximum flow indicated is for C3F8, which is the most challenging PFC for a

catalytic-based abatement device. Greater PFC flows and/or DREs can be obtained 

for other PFC gases and mixtures. Please contact Ecosys for more details. 

• Byproducts 

Byproducts for carbon-containing PFCs are CO2 and HF. HF is removed in the wet 

scrubber. 

• Cost of Technology (provided by supplier) 

$100,000 USD per unit. 

• Cost of Ownership 

Catalyst must be replaced periodically; lifetime >1 year. 
50 

Technology Transfer #05104693A-ENG ISMI 

• Pros 

– Commercially available technology that abates etch PFC emissions at 99% DRE 

and removes HF, generated as a result of catalyzing PFCs, from the exhaust stream. 

– Lower operating temperature than burner-scrubber units and no open flame. 

• Cons 

– Limited applicability. 

– Pre-scrubber required to prevent catalyst poisoning. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 

• Contact 

Brian Kingston 

brian.kingston@metrontech.com

Phone 408-887-6132 

• References 

robin.gardiner@metrontech.com

“EM Trinity Local Scrubber Efficiency Evaluation,” ITRI Taiwan, April 2004. 

“Catalytic Technology for Perfluorocompound (PFC) Emissions Control,” Solid State 

Technology, July 2001. 

R.S. Brown and J.A. Rossin, “Catalytic Process for Control of Perfluorocompound 

(PFC) Emissions, Semiconductor International, June 2001. 

b) Hitachi Super Catalytic Decomposition System (SCDS) 

• Description 

The Hitachi Super Catalytic Decomposition System (SCDS) is a point-of-use abatement 

device, installed post-vacuum pump, which uses state of the art catalytic methods to 

ensure maximum DRE of PFCs and process gases. The SCDS is available in 60, 120, or 

200 slm capacities. Each SCDS consists of a pre-spray and packed bed scrubber to 

remove particulates and water soluble acids, catalytic reactor and cooling section, and 

post-reactor packed bed scrubber to remove HF from the exhaust stream. The SCDS 

uses recirculated wastewater for each of the scrubber units, thus minimizing the amount 

of fresh water required. 

• Technology Status 

Commercially available. 

• Applicability 

The SCDS can abate CVD and etch emissions. Tool can be installed as a retrofit or 

during new tool installation on ≤150 mm, 200 mm, and 300 mm process tools. 
51 

ISMI Technology Transfer #05104693A-ENG 

• Required Utilities 

Model CD-60 CD-120 CD-200 

Capacity (slm) 60 120 200 

Electrical (kW) 4 8 11 

Water Usage (gpm) 0.4 0.6 0.9 

System Size (W × D × H) (mm) 991 × 559 × 1880 1143 × 635 × 1880 1143 × 635 × 1880 

• Reported Results 

DRE (%) 

PFC Maximum PFC Input Flow Rate (sccm) * # 

NF3 NT 99.9 

SF6 NT 99.9 

C2F6 1100 > 99 99.9 

CHF3 2400 > 99 99.9 

C4F8 NT 99.9 

C3F8 80 > 99 99.5 

CF4 7400 > 99 93 

C5F8 NT 99.9 

* Performance reported by semiconductor manufacturer for CD-120. 

# Supplier reported performance from website. 

• Byproducts 

Byproducts for carbon-containing PFCs are CO2 and HF. HF is removed in the wet 

scrubber. The fate of the N from NF3 is not described. 

• Cost of Technology (per unit) 

Not provided. Contact the supplier to obtain a quote. 

• Cost of Ownership 

Hitachi website states that catalyst replacement is required every 12–24 months; the 

pre-packed tower and pre-spray, cooling room and wastewater tank require annual 

cleaning; the packed tower requires cleaning every 2 years. According to a user, various 

parts are required for quarterly, semi-annual, annual or “as needed” maintenance. 

• Pros 

– Commercially available technology that abates both etch and CVD chamber clean 

PFC emissions at ≥99% DRE and removes HF, generated as a result of catalyzing 

PFCs, from the exhaust stream. 

– Recirculating scrubber results in low water consumption. 

– SCDS comes in three sizes and is capable of abating emissions from multiple 

process chambers. 

– Established technology. 
52 

Technology Transfer #05104693A-ENG ISMI 

• Cons 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 

– Cost of ownership needs to be evaluated. 

• References 

Hitachi America did not respond to requests for additional information submitted by the 

web and email. SCDS specifications were obtained from: http://www.hitachi-hta.com. 

Information on the SCDS was provided by Joachim Stache of Philips. 

c) TecHarmonic EHTVS/Alpine S 

• Description 

The TecHarmonic EHTVS/Alpine S catalytic scrubber is a comprehensive point-of-use 

abatement device for particulates, acid gases, flammables and PFCs. The Alpine S 

utilizes a high temperature, electrically heated thermal oxidizer chamber to preheat the 

exhaust stream, followed by a vortex particulate scrubber and packed bed tower which 

connects to a catalytic chamber to destroy PFCs, followed by a second vortex 

particulate scrubber and packed bed tower. Scrubber water re-circulation is used to 

minimize the amount of fresh water required by the system. The Alpine S is installed 

post-vacuum pump and can handle effluent from multiple process chambers and tools 

with a maximum flow capacity of 300 slm. The footprint is 965 mm × 1194 mm ×

1918 mm. 

• Technology Status 

Commercially available and installed in a PFC abatement application on an Applied 

Materials Centura 4 chamber SiN/TEOS deposition tool. 

• Applicability 

The Alpine S can abate CVD and etch emissions. The Alpine S is suited to handling all 

PFCs. Tool can be installed as a retrofit or during new tool installation on ≤150 mm, 

200 mm, and 300 mm process tools. 

• Required Utilities 

Water (1.5 gpm scrubber makeup water), N2, CDA, electricity, acid waste drain, cabinet 

exhaust, acid process exhaust. 
53 

ISMI Technology Transfer #05104693A-ENG 

• Reported Results from Manufacturing Installations 

DRE (%) 

PFC Maximum PFC Input Flow Rate (sccm) * # 

NF3 10,000# > 95 90–99 

SF6 6000# > 95 90–99 

C2F6 6000# > 95 90–99 

C3F8 6000# 90–99 

CF4 6000# 90 90–99 

C4F8 6000# 90–99 

CHF3 6000# 90–99 

*Performance reported by semiconductor manufacturer(s) 

#Supplier reported performance from manufacturing installations 

• Byproducts 

Byproducts for carbon-containing PFCs are CO2 and HF. HF is removed in the wet 

scrubber. Supplier reports that no NOx emissions are formed. 

• Cost of Technology (per unit) 

Not provided. Contact supplier to obtain a quote. 

• Cost of Ownership 

Periodic replacement of thermocouples and catalyst required. Frequency not reported. 

TecHarmonic estimates annual cost to operate the Alpine P to be ∼$17,000–$20,000 in 

PFC abatement applications. 

• Pros 

– Commercially available technology that abates particulates, acid gases, flammables 

and PFC emissions from etch and CVD chamber clean. 

– PFC DREs are 90–99% and device removes HF, generated as a result of PFCs 

destruction, from the exhaust stream. 

– Recirculating scrubber results in low water consumption. 

– Alpine S is capable of abating emissions from multiple process chambers. 

– The Alpine S has >1 year experience abating PFC from production. 

• Cons 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 

– Cost data must be obtained from supplier. 

– Limited performance data from semiconductor manufacturers. 
54 

Technology Transfer #05104693A-ENG ISMI 

• Contact 

Bill Delaney 

bdelaney@techarmonic.com

Phone 408-360-8780, x201 

• References 

Information on the Alpine S was provided by Francesca Illuzzi of STMicroelectronics 

and Bill Delaney of TecHarmonic. 

A.6.3 PFC Abatement – POU Electrically Heated Thermal – Scrubber Units 

• General Technology Description 

POU electrically heated thermal-scrubber units use an electrically heated chamber to destroy 

PFCs and other hazardous substances such as deposition precursors, followed by a water 

scrubber to remove volatile acid gases from the exhaust stream. Electrically heated thermalscrubber units are installed on the process tool exhaust line after the vacuum pump. 

Electrically heated-scrubber units can typically abate emissions from multiple process 

chambers. 

• Applicability 

Both CVD and etch effluents from ≤150 mm, 200 mm, and 300 mm process tools can be 

treated with the burner-scrubber units. 

• Pros 

– If >90% efficiency is obtained for all PFCs, total GHG emissions should be lower with 

this technology compared to burner-scrubbers. 

– By using electricity to heat the unit, a flammable fuel and open flame are not required 

which reduces potential fire risks for the fab. 

– Operating costs should be lower than burner-scrubber units, assuming units have high 

MTBF and low maintenance requirements. 

• Cons 

– High temperatures are required to abate CF4, a known byproduct of any plasma process 

using fluorocarbons or used to etch or clean carbon-based films. 

– Many electrically heated thermal-scrubber units cannot abate CF4. 

• Manufacturers of Electrically Heated-Scrubber Units Without Detailed Information in 

this Appendix 

Centrotherm CT-EW: As part of their modular abatement system design, Centrotherm is 

developing an electrically heated burner to abate pyrophoric deposition gases, NF3, and SF6. 

The unit has 600 slm capacity and uses CDA as the oxidation gas instead of O2. For more 

information on alpha and beta test results and commercial availability, contact Volker 

Kinzig, Volker.Kinzig@centrotherm.de, Phone 0049-7344-918-1801. 
55 

ISMI Technology Transfer #05104693A-ENG 

a) TecHarmonic EHTVS/Alpine P 

• Description 

The TecHarmonic EHTVS/Alpine P is a comprehensive point-of-use abatement device 

for particulates, acid gases, flammables and certain PFCs using dual high temperature, 

electrically heated thermal oxidizers followed by vortex particulate scrubber and twin 

packed bed towers. Scrubber water re-circulation is used to minimize the amount of 

fresh water required by the system. The Alpine P is installed post-vacuum pump and 

can handle effluent from multiple process chambers and tools with a maximum flow 

capacity of 800 slm. The footprint is 965 mm × 1194 mm × 1918 mm. 

• Technology Status 

Commercially available and installed in PFC abatement applications for >3 years. 

• Applicability 

The Alpine P can abate CVD and etch PFC emissions, but is most effective at abating 

SF6 and NF3. The Alpine S is better suited to handling carbon-containing PFC exhaust 

streams. Tool can be installed as a retrofit or during new tool installation on ≤150 mm, 

200 mm, and 300 mm process tools. 

• Supplier Reported Results from Manufacturing Installations 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 20,000 95–99 

SF6 6000 95–99 

C2F6* 6000 85–99 

C3F8* 6000 85–99 

* CF4 is a plasma process byproduct; CF4 abatement efficiency is not reported. 

• Byproducts 

Byproducts for carbon-containing PFCs are CO2 and HF. HF is removed in the wet 

scrubber. Supplier reports that no NOx emissions are formed. 

• Cost of Technology (per unit) 

Not provided. Contact supplier to obtain a quote. 

• Cost of Ownership 

Periodic replacement of thermocouples and gaskets is required. Frequency not reported. 

TecHarmonic estimates annual cost to operate the Alpine P to be ∼$5000. 

• Pros 

– Commercially available technology that abates certain PFC emissions from etch 

and CVD chamber clean at 85–95% DRE and removes HF, generated as a result of 

PFCs, from the exhaust stream. 

– Recirculating scrubber results in low water consumption. 
56 

Technology Transfer #05104693A-ENG ISMI 

– Alpine P is capable of abating emissions from multiple process chambers. 

– Established technology. 

• Cons 

– DRE for CF4 was not provided. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 

– Cost data must be obtained from supplier. 

– No user data provided by semiconductor manufacturers. 

• Contact 

Bill Delaney 

bdelaney@techarmonic.com

Phone 408-360-8780, x201 

• References 

Information on the Alpine P was provided by Bill Delaney of TecHarmonic. 

b) Kanken Techno KT1000 Series 

• Description 

Kanken Techno has developed the KT line of electrically heated thermal destruction 

units with pre-and post-scrubbers for comprehensive point-of-use abatement of 

particulates, acid gases, flammables and PFCs. The inlet scrubber removes hydrolytic 

effluents from the process such as SiF4 and WF6 and provides water to react with PFCs 

in the electric heater reactor. Kanken Techno has five different heater chamber designs 

which operate at different temperatures or exhaust flow rates. Selection of a particular 

system is dependent on the anticipated process emissions. The post-scrubber removes 

HF generated from PFC destruction and particulate. Scrubber water re-circulation is 

used to minimize the amount of fresh water required by the system. The KT1000 is 

installed post-vacuum pump and can handle effluent from multiple process chambers 

and tools. 

• Technology Status 

Commercially available with multiple installations in PFC abatement applications. 

• Applicability 

Tool can be installed as a retrofit or during new tool installation on ≤150 mm, 200 mm, 

and 300 mm process tools. See table below for applicability of specific systems. 
57 

ISMI Technology Transfer #05104693A-ENG 

• Required Utilities and Consumables 

Model KT100MF KT1000F KT1000H KT1000EX 

Applicability 

NF3 CVD 

Chamber 

Cleans 

NF3 CVD 

Chamber 

Cleans 

Etch and CVD Etch 

Total Capacity (slm) 400 250 200–250 120 for CF4

200 for SF6

Single Port 1100 × 1050 ×

Dimensions 1900 

(mm) Multi Port 1100 × 1350 ×

1900 

1050 × 1100 ×

1900 

1100 × 1350 ×

1900 

1100 × 1050 ×

1900 

Electrical 35 35 35 35 

(kVA) Avg. 7 7 7 7 

Water Usage (lpm) 10 10 10 10 

Process Gas (slm) NH3: 15 NH3: 6 N/A N/A 

Exhaust (slm) 1000 500 500 500 

Acid Waste Drain (lpm) 10 10 10 10 

Electric 

Heater 1/2 yr 1/2 yr 1/2 yr 1/2 yr 

Shower 

Nozzle Consumables 1/yr 1/yr 1/yr 1/yr 

Recycle 

Water Pump 1/yr 1/yr 1/yr 1/yr 

• Supplier Reported Results from Manufacturing Installations: KT1000MF 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 15000 > 99%* 

*< TLV: 10 ppm. 

• Supplier Reported Results from Manufacturing Installations: KT1000F 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 6000 > 99%* 

*< TLV: 10 ppm. 

• Supplier Reported Results from Manufacturing Installations: KT1000H 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

C4F8 7500 > 90 

C3F8* 7500 > 90 

C2F6* 6000 > 90 

CHF3* 7500 > 90 

* CF4 is a plasma process byproduct for this input chemistry; CF4 abatement efficiency is 16.6%. 
58 

Technology Transfer #05104693A-ENG ISMI 

• Supplier Reported Results from Manufacturing Installations: KT1000EX 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

CF4 3600 > 90 

SF6 6000 > 90 

• Byproducts 

Generates HF byproduct. HF is removed in the wet scrubber. KT1000EX generates SOx

emissions, which are removed by a wet scrubber. Supplier reports that no NOx

emissions are formed. KT1000MF and KT1000F introduce NH3 as a reactant gas to 

prevent the formation of NOx during NF3 abatement. 

• Cost of Technology (per unit) 

Not provided. Contact supplier to obtain a quote. 

• Cost of Ownership 

Operating costs not provided. Required consumables and replacement frequency 

reported above. 

• Pros 

– Commercially available technology that abates PFC emissions from specified 

applications at >90%DRE and removes HF, generated as a result of PFC 

destruction, from the exhaust stream. 

– Recirculating scrubber results in low water consumption. 

– Capable of abating emissions from multiple process chambers. 

– Commercially available, established technology with large installed base. 

• Cons 

– CF4 is a byproduct of plasma processes using C-F chemistries; KT1000EX is only 

KT unit capable of abating CF4 >90% DRE. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 

– Cost data must be obtained from supplier. 

– No data provided by semiconductor manufacturers. 

• Contact 

Tatsuro Beppu 

81-6-6380-1474 

mailto:beppu@kanken-techno.co.jp

• References 

Information on the KT1000 Series was provided by Tatsuro Beppu of Kanken-Techno. 
59 

ISMI Technology Transfer #05104693A-ENG 

A.6.4 PFC Abatement – POU Atmospheric Plasma Units 

• General Technology Description 

Point-of-use atmospheric plasma units use plasma at atmospheric pressure to destroy PFCs 

and other hazardous substances such as deposition precursors. The plasma reactor can be 

followed by a water scrubber, which may contain a base solution, to remove volatile acid 

gases from the exhaust stream. Atmospheric plasma units are installed on the process tool 

exhaust line after the vacuum pump and, thus, the exhaust stream entering the unit contains a 

large amount of nitrogen, which can impact the plasma efficacy. Atmospheric plasma units 

are typically designed to abate emissions from multiple process chambers. 

• Technology Status 

Commercially available. 

• Applicability 

Emissions from ≤150 mm, 200 mm, and 300 mm process tools can be treated. 

• Pros 

– By using plasma, a flammable fuel and open flame are not required which reduces 

potential fire risks for the fab. 

– Operating costs should be lower than burner-scrubber units, assuming units have high 

MTBF and low maintenance requirements. 

– Using post-pump plasma minimizes the risk of fluorine or HF formation in the vacuum 

pump that could lead to pump corrosion. 

– Unlike pre-pump plasma systems, post-pump plasma units pose no risk of particulates 

diffusing back into the process chamber. 

• Cons 

– POU atmospheric plasma units are a relatively new and unproven technology. 

– Little data is currently available on DRE, uptime, maintenance requirements, and COO. 

a) Air Liquide UPAS 

• Description 

Air Liquide has developed an atmospheric microwave plasma system/dry adsorption 

system. Integration of universal plasma abatement system (UPAS) technology into a fab 

may require installation of pretreatment technology and will require post-UPAS 

abatement to remove HF from the exhaust stream. Centralized wet scrubbers installed 

for acid exhaust may be adequate. Air Liquide makes two versions of the UPAS. The 

Compact UPAS is 635 mm × 700 mm × 1900 mm while the Integrated UPAS is 635 

mm × 1300 mm × 1900 mm. The UPAS can handle effluent from multiple process 

chambers with maximum flow of 120 slm. 

• Technology Status 

Commercially available with 14 units currently installed in manufacturing fabs. 
60 

Technology Transfer #05104693A-ENG ISMI 

• Applicability 

UPAS is marketed for etch process emissions; however, a paper was presented at 

ISESH 2005 on application to CVD chamber cleans. Device can be installed as a 

retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm process 

tools. 

• Required Utilities 

Electricity, N2, CDA, cooling water, acid exhaust, process heat exhaust. 

• Reported Results 

PFC Maximum PFC Input Flow Rate (mg/m3) DRE (%) 

C4F8 6700 > 99 

CF4 7300 > 90 

CH2F2 500 > 99 

CHF3 6700 > 95 

• Byproducts 

ESIA member notes NOx is generated at ∼250 mg/m3. 

• Cost of Technology (per unit) 

Not provided. Contact supplier to obtain a quote. 

• Cost of Ownership 

Air Liquide notes periodic replacement of ceramic tube (2 tubes as backup), cooling oil 

(120L), gaskets and other parts may be required. Frequency not reported. ESIA member 

notes dry cartridges as a consumable. 

• Pros 

– PFC and fluorinated species abatement with reduced corrosion and safety risk in 

main exhaust. 

– Potentially lower operating cost than fueled burner-scrubber units; however, 

technology is relatively new and little information is publicly available on uptime 

and COO. 

• Cons 

– Limited applicability. 

– May require installation of separate pretreatment system to remove particulates and 

acid gases. 

– Does not remove HF or other acids generated in plasma; semiconductor 

manufacturers must determine if central wet scrubbers can sufficiently abate 

additional UPAS effluent. 

– NOx is generated by the plasma system (cracking of O2 and N2) and is not treated 

by dry cartridge. 

– Solid deposition in the cartridge is NOx-based. 
61 

ISMI Technology Transfer #05104693A-ENG 

• Contact 

Olivier Letessier 

olivier.letessier@airliquide.com

Phone +33 1 40 62 5234 

• References 

Information provided by ESIA members and Olivier Letessier of Air Liquide. 

H. Yamamoto (Ricoh Electronics Devices), “Perfluorocompound (PFC) Atmospheric 

Plasma Abatement for Etch and Chemical Vapor Deposition (CVD),” ISESH, 2004. 

H. Yamamoto (Ricoh Electronics Devices), M. Tabata (Air Liquide Japan – Tokyo, 

Japan), M. Sato and C-H. Ly (Air Liquide Laboratories, Ibaraki, Japan), and 

J.C. Rostaing (Centre de Recherche Claude Delorme, Les-Loges-en-Josas, France), 

“Perfluorocompound (PFC) Atmospheric Plasma Abatement System for Chemical 

Vapor Deposition (CVD) at Ricoh: A Pertinent Approach,” ISESH, 2005. 

b) BOC Edwards Zenith Etch Plasma 

• Description 

BOC Edwards offers the Zenith Etch Plasma, an atmospheric microwave plasma unit 

followed by a three-stage wet scrubber incorporated with high-efficiency vacuum 

pumps for plasma etch chambers. The Zenith Etch Plasma system is not a standalone 

abatement device; four vacuum pumps are included. The footprint is 1300 mm ×

625 mm × 1833 mm, which includes the abatement system and pumps. 

• Technology Status 

Zenith Etch Plasma is commercially available only in Europe at this time. 

• Applicability 

Zenith Etch Plasma system is available as a retrofit or as part of a new tool installation 

for etch systems only. 

• Required Utilities 

Water, electricity, N2, O2, PCW, acid exhaust, general exhaust. 

• Supplier Reported Results 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

NF3 1000 > 99 

SF6 1000 > 99 

C4F6 1000 > 99 

C4F8 1000 > 99 

CF4 800 91 

CH2F2 1000 > 99 

CH3 1000 > 99 
62 

Technology Transfer #05104693A-ENG ISMI 

• Byproducts 

All PFCs are converted to CO2 and HF. BOC Edwards reports HF is removed by a wet 

scrubber, and NOx emissions are within desired levels. 

• Cost of Technology (provided by supplier) 

As a package including abatement and 4 vacuum pumps, the Zenith Etch system is 

between $50,000–$75,000 USD per etch chamber depending on the configuration (all 

piping between pumps and abatement included). 

• Cost of Ownership 

BOC Edwards lists as consumables electrode, seals, gaskets as needed for annual PM. 

BOC Edwards reports consumables costs are typically <$3000 USD and typical 

facilities costs based on Fab Utility Cost Values for Cost of Ownership (COO) 

Calculations (SEMATECH, Technology Transfer #02034260A-TR), the fab utility cost 

values are ∼$4000 USD. 

• Pros 

Potentially lower operating cost than fueled burner-scrubber units; however, technology 

is relatively new and little information is publicly available on uptime and COO. 

• Cons 

Limited applicability and availability. 

• Contact 

Joe Van Gompel 

joe.vangompel@bocedwards.com

Phone 512-633-5105 

• References 

M. Radiou, A. Seeley, S. Carss, and J. Van Gompel, “Sixty Percent Utilities Savings on 

Etch Perfluorocompound (PFC) Abatement,” SEMICON West, July 2003. 

c) Centrotherm Plasma-Washer 

• Description 

Centrotherm has developed a modular point-of-use abatement system whose 

components can be specified based on the specific requirements of the process being 

abated. The Centrotherm plasma-washer combines a microwave plasma stage and a 

separate high efficiency wet scrubber section. Dry bed absorber or catalysts are 

alternatives to the wet scrubber section. The unit is installed after the vacuum pump and 

operates at atmospheric pressure. The footprint is dependent on system configuration. 

The unit can handle effluent from multiple chambers with a maximum flow capacity of 

120 slm. 

• Technology Status 

Alpha and beta testing. 
63 

ISMI Technology Transfer #05104693A-ENG 

• Applicability 

Centrotherm’s plasma-washer can be installed as part of a new etch tool installation or 

as a retrofit for etch processes; CVD is problematic due to powder generation. 

• Required Utilities 

Electricity, water or oxygen as reactant, nitrogen; scrubber water, KOH or NaOH for 

scrubber. 

• Supplier Reported Results (no semiconductor manufacturer provided data 

available) 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

SF6 2000 80–90* 

C2F6 2000 80–90* 

CF4 2000 80–90* 

*Depending on set-up. 

• Byproducts 

No information provided on byproducts. 

• Cost of Technology (provided by supplier) 

$115,000–$130,000 USD per unit. 

• Cost of Ownership 

Electrodes for the plasma tube must be replaced periodically (contact supplier to obtain 

additional information). 

• Pros 

– By using plasma, a flammable fuel and open flame are not required which reduces 

potential fire risks for the fab.

– Operating costs should be lower than burner-scrubber units, assuming units have 

high MTBF and low maintenance requirements.

– Using post-pump plasma minimizes the risk of fluorine or HF formation in the 

vacuum pump that could lead to pump corrosion.

– Unlike pre-pump plasma systems, post-pump plasma units pose no risk of 

particulate back diffusion into the process chamber.

• Cons 

– Relatively new and unproven technology with limited applicability. 

– Little data available on DRE, uptime, maintenance requirements, and COO; 

however, it is not recommended for CVD due to particulates and polymeric buildup 

in the plasma tube. 

– To be used as a retrofit in an existing fab requires floor space, which may be 

limited. 
64 

Technology Transfer #05104693A-ENG ISMI 

• Contact 

Volker Kinzig 

Volker.Kinzig@centrotherm.de

Phone 0049-7344-918-1801 

• References 

Semiconductor contacts are MUT Jena and Innovent (Jena, Germany). 

Information provided by Volker Kinzig of Centrotherm.

d) Desiccant Technology Corporation (D-Tech) Plasma + Wet Scrubber Model 

LT-DP200VI 

• Description 

D-Tech has developed an integrated atmospheric plasma and wet scrubber system to 

abate PFC and chlorofluorocarbon emissions from etch and CVD processes. The unit 

also destroys CVD precursors and treats SiF4 byproducts. The unit is 1200 mm ×

1000 mm × 1850 mm and can handle effluent from multiple chambers with a maximum 

flow capacity of 600 slm. 

• Technology Status 

Commercially available. 

• Applicability 

Plasma + Wet Scrubber can be used to abate both etch and CVD emissions. Device can 

be installed as a retrofit or during new tool installation on ≤150 mm, 200 mm, and 

300 mm process tools. 

• Required Utilities 

Electricity (220 V, 40 A, 50/60 Hz), N2 (45 lpm @ 5 kg/cm2), CDA (30 lpm @ 3–

5 kg/cm2

), cooling water (40 lpm @ 3–5 kg/cm2), city water (2.5 lpm @ 3 kg/cm2). 

• Supplier Reported Results (no semiconductor manufacturer provided data 

available) 

PFC Maximum PFC Input Flow Rate (sccm) DRE (%) 

CF4 250 > 99 

C2F6 4000 > 99 

CHF3 1000 > 99 

• Byproducts 

HF is formed. 

• Cost of Ownership 

D-Tech reports replacement of torch (1 each/40 days), thermocouple (5 each/year), and 

O-ring seal (8 each/6 months). 
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ISMI Technology Transfer #05104693A-ENG 

• Pros 

– Potentially lower operating cost than fueled burner-scrubber units; however, 

technology is relatively new and little information is publicly available on uptime 

and COO. 

• Cons 

– May require installation of separate pretreatment system to remove particulate and 

acid gases. 

– Does not remove HF or other acids generated in plasma; semiconductor 

manufacturers must determine if central wet scrubbers can sufficiently abate 

additional UPAS effluent. 

• Contact 

Art Liu 

art@dtech.com.tw

Phone +886-3-5832511 

• References 

Information provided by Art Liu of D-Tech. 

A.6.5 PFC Abatement – POU Foreline Plasma Units 

• General Technology Description 

POU foreline plasma units employ a compact, low-pressure plasma reactor to destroy PFCs 

from etch processes. Foreline plasma units are installed on the foreline after the turbo pump 

but before the mechanical vacuum pump, where they can abate concentrated emissions 

before dilution with N2 purge from the vacuum pump. One unit is required per etch process 

chamber. 

• Technology Status 

Commercially available. 

• Applicability 

Device can be installed as a retrofit or during new tool installation on ≤150 mm, 200 mm, 

and 300 mm etch process chambers. 

• Pros 

– Compact footprint and potentially lower COO solution to abate etch PFC emissions. 

• Cons 

– Does not remove HF or other acid gases generated in plasma that are then fed into the 

vacuum pump. 
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– Semiconductor manufacturers must monitor impact of acid gases on vacuum system 

and determine if central wet scrubbers have sufficient capacity to abate additional acid 

gases generated by the pre-pump plasma units. 

– In certain applications, pre-pump plasma units pose a potential risk of particles diffusing 

back into the etch process chamber. 

a) Advanced Energy (AE) PCS (successor to Litmas Blue) 

• Description 

The PCS is a high density, inductively coupled plasma generator that is installed on the 

foreline between the turbo and mechanical vacuum pumps of an etch chamber to 

decompose unused PFCs into ions and free radicals as they enter the vacuum pump. 

Water vapor is added to ensure conversion to HF. Placement of the PCS in the foreline 

results in energy-efficient decomposition of PFC emissions when they are most 

concentrated (i.e., before dilution with nitrogen purge from the vacuum pump). The 

PCS operates so that the plasma is ON when PFC gases flow in the process chamber 

and OFF when the chamber is idle. AE has partnered with CS Clean Systems to sell and 

service the AE line of PFC abatement products, including the PCS. AE makes 1500 W 

and 3000 W models of the PCS. Footprint of both units is 398 × 274 × 264 mm. 

• Technology Status 

Commercially available with multiple units currently installed in manufacturing fabs. 

• Applicability 

The PCS is applicable to etch processes. Device can be installed as a retrofit or during 

new tool installation on ≤150 mm, 200 mm, and 300 mm process tools. One unit is 

required per etch process chamber. 

• Required Utilities 

Water, electricity. 

• Reported Results 

PFC Maximum PFC Input Flow Rate (ppm) DRE (%) 

CHF3 700 >> 95 

CF4 850 > 90 

• Byproducts 

HF, NO2, and COF2 at low ppm level. 

• Cost of Technology (per unit) 

Not reported. Contact CS Clean Systems. 

• Cost of Ownership 

Plasma tube requires periodic replacement. 5% increase in COO. 
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ISMI Technology Transfer #05104693A-ENG 

• Pros 

– Potentially lower COO solution to abate etch PFC emissions because PFCs are 

treated before dilution by pump purge nitrogen. 

• Cons 

– Does not remove HF or other acid gases generated in plasma that then feed into the 

vacuum pump. 

– Semiconductor manufacturers must monitor impact of acid gases on vacuum 

system and determine if central wet scrubbers have sufficient capacity to abate 

additional acid gases generated by the PCS. 

– CS Clean Systems makes CLEANSORB dry absorber system to remove HF. 

• Contact 

Contact CS Systems for additional information. 

• References 

Information provided by Ton van de Kerkhof of Philips. Additional information 

obtained from the CS Clean Systems. http://www.cscleansystems.com/index.asp. 

b) Ecosys Barracuda 

• Description 

The Ecosys Barracuda is a low-pressure plasma reactor that is installed on the foreline 

between the turbo and mechanical vacuum pumps of an etch chamber. Placement of the 

Barracuda in the foreline results in energy-efficient decomposition of PFC emissions 

when they are most concentrated (i.e., before dilution with nitrogen purge from the 

vacuum pump). The plasma is ON when PFC gases flow in the process chamber and 

OFF when the chamber is idle. Plasma power can be adjusted to achieve appropriate 

DRE, depending on the PFC gas mixture and flow rate. To ensure PFC byproducts are 

not formed, Barracuda utilizes water vapor as a reactant. Reactor size is 45.7 × 25.4 ×

25.4 cm. Dimensions of the controller, which can be located remotely, are 38.1 × 25.4 ×

20.3 cm. 

• Technology Status 

Currently undergoing beta testing. 

• Applicability 

Ecosys Barracuda is being developed to abate etch process emissions. Device can be 

installed as a retrofit or during new tool installation on ≤150 mm, 200 mm, and 300 mm 

etch process tools. One unit is required per process chamber. 

• Required Utilities 

Water, electricity. 
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• Reported Results 

DRE (%) 

PFC Maximum PFC Input Flow Rate * # 

CHF3 850 ppm* >> 95

CF4 700 ppm* / 120 sccm# > 90 90

* Performance reported by semiconductor manufacturer 

# Supplier reported performance – maximum flow indicated is for CF4, which is most challenging PFC 

to abate. Greater flows and DREs can be obtained for other PFCs and gas mixtures. Contact Ecosys for 

more details. 

• Byproducts 

HF, COF2, NO2, CO, and CO2. 

• Cost of Technology (provided by supplier) 

Target price: $30,000 USD per unit. 

• Cost of Ownership 

Ceramic plasma tube requires periodic replacement (lifetime estimated to be >1 year). 

Pros 

– Small footprint and potentially lower COO solution for abating etch PFC 

emissions. 

• Cons 

– Because unit is undergoing beta testing, little information is available about longterm reliability and COO. 

– Does not remove HF or other acid gases generated in plasma that then feed into the 

vacuum pump. 

– Semiconductor manufacturers must monitor impact of acid gases on vacuum 

system and determine if central wet scrubbers have sufficient capacity to abate 

additional acid gases generated by the Barracuda. 

– If necessary, dry bed absorber system or wet scrubber can also be installed postpump to abate HF. 

• Contact 

Sebastien Raoux, Ecosys 

408-719-4668 

Sebastien_Raoux@metrontech.com

• References 

Information on the Ecosys Barracuda was provided by Ton van de Kerkhof of Philips 

and Sebastien Raoux of Ecosys. 
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ISMI Technology Transfer #05104693A-ENG 

A.6.6 PFC Abatement – Centralized Atmospheric Plasma Unit 

• General Technology Description 

The only centralized PFC abatement system is a corona discharge system jointly developed 

by FH Co., Ltd and Samsung Electronics in Korea. The technology is undergoing beta 

evaluation by Samsung. At the beta site, a separate PFC exhaust is installed post-vacuum 

pump to segregate CVD chamber clean emissions from deposition emissions. The PFC 

exhaust passes through the annular space between co-axial cylindrical electrodes used to 

sustain a corona discharge at atmospheric pressure. Exhaust from the abatement system then 

flows to the house scrubber for removal of acid gases. The unit has a capacity of 50 cubic 

meters/minute and dimensions of 1500 × 3330 × 1731 mm. Multiple units can be installed to 

provide required capacity. Deposition process exhaust goes to separate flammable duct. 

• Technology Status 

Extensive beta testing (20+ months). Multiple units installed in fabs in Korea. 

• Applicability 

PFC emissions from semiconductor and LCD display CVD chamber cleans. 

• Pros 

– Centralized abatement for CVD chamber clean PFC emissions. 

– Modular design allows for installation of multiple units to achieve required flow 

capacity. 

• Cons 

– New technology with limited installations. 

– Little detailed information available on DRE, maintenance requirements, COO, 

reliability, and uptime. 

– Requirement of separate exhaust system for PFCs may make use of this technology as a 

retrofit difficult due to space limitations in existing fabs. 

• Required Utilities 

Power consumption is 220 V, 6 A. 

• Reported Results 

PFC Maximum PFC Input Flow Rate (ppm) DRE (%) 

NF3 65 91.2 

C3F8 110 90.1 

• Byproducts 

Not reported. Exhaust flows to central wet scrubbers. 

• Cost of Technology (provided by supplier) 

$500,000 USD per unit. 
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• Contact 

FH Co., Ltd.: Young-Hee Lee 

master@forhuman.co.kr

• References 

S-K Chae, “New Large-Scale End-of-Pipe Perfluorocompound (PFC) Abatement System 

Using a High-Efficiency Atmospheric Discharge Technology,” SEMICON West 2004, 

STS:ISM Program, July 2004. 

Additional information provided by Wang-Keun Kim of Samsung. 

International SEMATECH Manufacturing Initiative 

Technology Transfer 

2706 Montopolis Drive 

Austin, TX 78741 

http://ismi.sematech.org 

e-mail: info@sematech.org