Transcript korea2 - University of Arizona

Global Warming Science:
Status and Statistics
Phyllis Pei
Walter Worth
Sematech
 1999 Arizona Board of Regents for The University of Arizona
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Perfluorocompounds
(NF3, SF6, C2F6, CF4, CHF3)
•
Have long atmospheric lifetimes
•
Stable, non-toxic
•
Strong infrared absorbers
•
Continuing emissions will likely accumulate with
unknown consequences
•
Some, such as C2F6, are made solely for use in
semiconductor manufacturing
•
Most PFC gas is not “consumed” in the etch and CVD
processes
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Key Greenhouse Gases
Affected by Human Activity
ATMOSPHERIC CONCENTRATION
GAS
CO2
UNIT
ppmv
Pre-Industrial
(1750-1800)
280
Present
(1990)
353
Atmospheric
Lifetime (Yrs)
50-200
CH4
ppmv
0.8
1.72
10
N2O
ppbv
288
310
150
CFC-11
pptv
0
280
65
CFC-12
pptv
0
484
130
PFCs
pptv
0
100
700-50,000
NOTE: H2O has largest greenhouse effect, but is not affected by human sources and sinks
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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PFC Lifetimes and GWPs
GAS
ATMOSPHERIC
LIFETIME (years)
GWP
CF4
50,000
6,300
C2F6
10,000
12,500
SF6
3,200
24,900
CHF3
250
12,100
NF3
~740
8,000
CO2 (reference)
50-200
1
GWP = Global Warming Potential @ 100 year time horizon
Source: IPCC
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
Pei & Worth
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Global Warming Potential (GWP)
The following equation is used to calculate GWP:
t
a i c i dt
0
GWPt=
t
a co cco dt
2
2
0
where:
a1 = the instantaneous radiative forcing resulting from a unit increase in the
atmospheric concentration of trace gas, i
c1 = concentration of trace gas, i, remaining in the atmosphere at time, t, after
release of unit mass at t=0
t = number of years over which the calculation is performed
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
5
Million Metric Tons Of
Carbon Equivalents (MMTCE)
MMTCE =
12 x Kg x GWP100
44
109
GWP100 = global warming potential at 100 yr. time horizon
Kg = weight of PFC emitted
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Global Warming Calculations
Wavelength & Molecular Size & Lifetime
[ Rad. Forcing & Conc. & Time ]
{ [GWPt] & Mass }
{ Million Metric Tons Carbon Equivalent }
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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U.S. Greenhouse Gas Emissions
Each source,
although small,
contributes to the
whole
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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PFC Emissions/Use Chart
Data Source: EPA & Dataquest
Tons/year
45,000
40,000
35,000
30,000
25,000
20,000
15,000
10,000
5,000
0
33,000
7,500
Global PFC
Emissions from
Aluminum
Industry
U.S. PFC
Emissions from
Aluminum
Industry
300
U.S.
Semiconductor
Industry Use of
PFCs
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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1993 PFC Purchases
(U.S. Semiconductor Industry)
1993 Purchases of PFCs (metric tons)
CF4
C2F6
NF3
SF6 Total
Estimated U.S. Total
67
177
18
45
307
% of Total
22
58
6
14
100
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Chronology - PFC Technology Development
1994 -
Tested first commercial PFC thermal
destruction device (Delatech’s CDO)
-
Alzeta develops and installs first inwardly-fired burner at
SEMATECH
-
MIT starts screening PFC alternative chemicals
1995 -
Alzeta licenses burner technology to Edwards
IBM demonstrates 50% C2F6 reduction by process
optimization
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Chronology - PFC Technology
Development (Cont’d)
-
Edwards develops and SEMATECH tests prototype
burnbox
-
MIT successfully destroys destruction of PFCs in
microwave reactor
-
Novellus and 3M develop C3F8 as C2F6 replacement
1996 -
Beta testing of PFC capture technologies
• Air Products/Radian at TI
• Air Liquide at TI
• BOC at IMEC
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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Chronology - PFC Technology
Development (Cont’d)
-
Schumacher unveils potential PFC alternative (TFAA)
-
C3F8 is being evaluated in fabs at TI and AMD as
drop-in replacement for C2F6
-
Edwards improves burnbox to destroy CF4, tested at
Motorola
-
DuPont announces PFC replacement studies
Pei & Worth
NSF/SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing
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