WO 2005/015608 PCT/US2004/017977
METHOD OF INHIBITING CORROSION OF COPPER PLATED OK
METALLIZED SURFACES AND CIRCUTTRY DURING SEMICONDUCTOR
MANUFACTURING PROCESSES
5 TECHNICAL FIELD
This invention relates to a method and apparatus for inhibiting corrosion of
topper plated or metallized surfaces and circuitry in semiconductor devices immersed
in water durag sesniconducwi maraifactarifig processes -usiag aromatic triazole
10 corrosion inhibitors where the concentration of the corrosion inhibitor in the water is
precisely monitored and controlled fluorometfically.
BACKGROUND OF THE INVENTION
15 Semiconductor chip manufacturers use a variety of azoles to prevent in-process
manufacturing corrosion of copper plated or metallized surfaces and circuitry in the
semiconductor devices. Typically, at different points in the manufacturing process, the
chips are immersed in treatment baths containing a solution of ultra pure water and
azole corrosion inhibitor. Over time, the azole content of the solution can be depleted,
20 for example by chemical/physical adsorption cynio the copper plated or metallized
surfaces and circuitry, biodegradation. or by incidental dilution of the inhibiting
solution wiih. water that does not contain correct azole levels. In addition, azoles
adsorb onto the surface of the semiconductor divices. Thus, when the. semiconductor
devices are removed from the treatment bath and replaced, azole is removed with the
25 devices from the treating system resulting in a removal of corrosion inhibitor from the
system with ito significant fluid loss. Additional azolc is removed from the system,
along with fluid due to the adherence of the fluid to the semiconductor devices.
Removal of azole through removal of copper-coated semiconductor devices is
distinctive from traditional applications of azoles (such as open recircularing cooling
30 water systems) where physical removal of treated surfaces from the system is not a
routine occurrence.
Corrosion protection while the chips are immersed in ihe treatment bath is
essential to ensure that the semiconductor devices will work as intended. Corroded
metal surfaces, will nut function, properly in manufactured integrated circuits (reduced

WO 2005/015608 PCT/US2004/017977
"yield") as compared to metal surfaces circuits that have been property treated for
corrosion inhibition. Thus, it is crucial that effective amounts of corrosion inhibitor be
maintained in the aqueous treatment solution bath for the copper plated or metallized
surfaces and circuitry m order to optimize the yield of the final integrated circuits and
5 the manufacturing process as a whole.
Furthermore, it may be necessary to remove the azoles from the semiconductor
device prior to certain, downstream, manufactaring processes. as the presence of the
azole can interfere with those processes. Excessive feed of the azoles delays the
removal processes and the subsequent manufacturing steps, causing a reduced output
10 rate. Insufficient removal can cause yield problems. Finally, impurities including
azoles must be removed from the water, or the azole dosage characterized and
controlled, before the water can be discharged or recycled. Therefore, excessive
dosing of azole is uneconomical.
Existing methods of determining the concentration of azoles in water include
15 indirect methods such as colorimetric analysis which requires photolysis of a fluid
sample and formation of a colored dimerization product and light absorbance methods
which may be inaccurate at high or low azole concentrations. None of the foregoing
methods provide for automatic or continuous control of azole concentration in the
aqueous fluid.
20 Accordingly. There is an ongoing need for methods of inhibiting corrosion of
copper plated or metallized surfaces and circuits in semiconductor devices that
incorporaies precise control of corrosion inhibitor concentration to ensure that a
effective corrosion inhibition is maintained throughout the manufacturing process
without overdosing of inhibitor.
25
SUMMARY OF THE INVENTION
This invention is a method of inhibiting corrosion of copper plated or
metallized surfaces and circuitry in semiconductor devices immersed in an aqueous
30 fluid in a treatment bath comprising
(i) adding to die aqueous fluid an effective corrosion inhibiting amount of one or
more aromatic triazole corrosion inhibitors;
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WO 2005/015608 PCT/US2004/017977
(ii) fluorometrically monitaring the concentration of aromatic triazole corrosion
inhibitors in the aqueous fluid; And
(iii) adding additional aromatic azole corrosion inhibitor to the aqueous fluid to
maintain an effective corrosion inhibiting concentration of the aromatic triazole
5 corrosion inhibitor in the aqueous fluid.
The present invention permits accurate and continuous control of aromatic
triazolc concentration within a specific concentration range in order to compensate for
any processes leading to changes intriszole concentration during the manufacturing
process or due to a desire by the operator to change triazole concentration at any point
10 in the manufacturing process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a working curve for benzotriazole showing fluorescence intensity
1 5 versus benzotriasole concentration in aqeuous solution at benzotriazole doses of 0, I,
5,10,25, 50, 250, 500 and 1,000 ppm.
FIG. 2 shows a typical treatment bath used in various manufacturing processes
for copper plated or metallized seiniconductor devices in which the semiconductor
devices 5 are immersed in ultrapure water in a treatment bath 4 containing one or more
20 fluid inlets 10 and fluid outlets 11. The treatment bath 4 includes means 16 such as a
removable rack rbr supporting, the semiconductor devices 5 in the treatment bath 4.
Aromatic azole corrosion inhibitor solution contained in supply reservoir 1 is added
into the treatment bath 4 using feeder line 2 through valve 3. Valve 3 may be replaced
with or used im combination with a fluid addition pump (not shown). Fluid is
25 circulated through the treatment bath 4 by pumping through fluid transfer lines 6 into
the treatment bath 4 through inlets 10 and out of the treatment bath through outlets 11
using recirculating pump 7. Excess fluid resulting fom audition of the aromatic azole
corrosion inhibitor solution or other additives is removed from the system thraugh
drain or overflow pipe 8 which is opened or closed using valve 9.
30 FIG. 3 shows an embodiment of this invention where the treatment bath 4 is
equipped with means 12 for fluotometrically monitoring and controlling the
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concentration of aromatic azote corrosion inhibitors in the treatment bath where the
monitoring and control means 12 are installed directly in a fluid transfer line 6.
FIG. 4 shows an alternative embodiment of this invention where the monitoring
and control means 12 are disposed along a side stream sample line 13 connected to a
5 treatment bath fluid transfer line 6 through pump 14.
DETAILED DESCRIPTION OF THE INVENTION
This invention is a method of inhibiting corrosion of the copper plated or
10 XXX surfaces and circuits in semiconductor devices while the devices are
immersed in aqueous fluids in various stages of integrated circuit manufacturing
processes. As used herein, "aqueous fuid" means ultrapure water, orultiapure water
containing alcohols, ocganic solvents, or other arocessing additives. typically usad in
the manufacture of semiconductor devices.
15 "Semiconductor manufacturing process" or "integrated circuit manufacturing
process" includes all processes employed in the manufacture of these devices,
including, for example, photolithography, etching, plating, doping, polishing,
metallizing, and the like.
According to this invention, aromatic triazole corrosion inhibitors are added to
20 the aqueous fluid in an effective corrosion-inhibiling amount The concentration of the
inhibitors in the aqueous fluid is directly and accurately fluonitored fluorometrically
such that additional aromatic triazole corrosion inhibitor can be added to replace
corrosion inhibitor that is depicted or removed during the manufacturing process
without detrimental or uneconomical overdosing of inhibitor.
25 Aromatic triazole corrosion inhibitors suitable for use in this invention include
copper metal corrosion inhibitors comprising a triazole ring fused to an aromatic ring.
Representative aromatic triazole corrosion inhibitors include benzotriazole,
butylberizotriazole, tolyltriazole, naphthorriasole, chlarobenzotriazole,
bromobenzomazole. chlorotolyltriazole, and bromotolyllriazoie. 'Tolyltriazole"
30 includes 4 -methylbenzotriazoloe and 5 -methylbenzotriazole and mixtures thereof,
including the mixtures disclosed in U.S. Patent No. 5,503,775, incorporated herein by
reference.
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As used herein, "aromatic ring" means substituted and unsubstitufed aromatic
carbocyclic radicals and substituted and unsubstituted heterocyclic radicals having
about 5 to about 14 ring atoms, Representative aryl include phenyl, naphthyl,
phenenthryl, anthracyl, pyridyl, furyl, pynolyl, quinolyl, thienyl, thiazolyl, pyriXXXidyl,
5 indolyl, and the like- The aryl is optionally substituted with one or more groups
selected from hydroxy, halogen. C1-C4 alkyl, C1-C4 alkoxy, C1C4 alkenyl, C1-C4
alkynyl, mercapto, sulfonyl. carboxyl, amino and amido. Preferred aromatic rings
include phenyl and naphthyl.
"Aikoxy" means an alkyl group attached to the parent molecular moiety
10 through an oxygea atom.. Representative alkoxy groups ID INClude methoxy, elhoxy,
propoxy. butoxy, and the like,
"Alkyl" means a monovalent group derived from a straight or branched chain
saturated hydrocarbon by the removal of a single hydrogen atom. Representative alky]
groups include methyl, ethyl, XXX- and iso-propyl, XXX-,sec-, iso- and tert-butyl, and the
15 like.
" Alkenyl" means a-inoaovaleat group derived from a hydrocarbon containing at
least one carbon-carbon double bond by the removal of a single hydrogen atom.
Representative alkenyl groups include ethenyl, propenyl, butenyl, l-methyl-2-buten-l-
yl, and the like.
20 "Alkynyl" means a monovalent group derived from a hydrocarbon containing
at least one carbon-carbon triple bond by the removal of a single hydrogen atom.
Representative alkynyl groups include cthynyl, propynyl, 1- and 2-butynyl, and the
like.
"Amido" means a group of formula -C(O) NR'R" where R.1 and R" are as
25 defined herein. Representative amido groups include methylaminocarbonyl,
ethylXXX, iso-propylkminocatbonyl and the like.
"Amino" means a group having the. structure -N8 "R" wherein, R1 and R11 arc
independently selected from H and XXX alky1. Representative amino groups include
amino (NH2). dimethylamino, diethylamino, methylethylamino and the like.
30 "Carboxyl" means a group of formula -CO2H.
"Halogen" means Br, Cl, F or I.
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WO 2005/015608 PCT/US2004/017977
"Mercapto" means a group of formula -SR' where R' is defined herein.
Representative mercapto groups include -SH, thiomethyl(-SCH3), thioethyl (-
SCH2CH3), and the like.
"Sulfonyl" means a group of formula -SO3H.
5 Preferred aromatic trozole corrosion inhibitors are elected from the. group
consisting of benzotriazole, burylbenzotriazole, tolyltriazole and naphthotriazole.
Benzotriazole, butyl benzorrtazole, tolyltriazole are more preferred.
The aromatic triazole corrosion inhibitor is typically added as a solution in
alcohol or as aqueous solution with one or more alcohols. Suitably alcohols include
10 methanol, ethanol, isopropaaol, ethylene glycol, propylene glycol, diethylene gtycol,
triethanol amine, and the like. Representative corrosion inhibitor solutions comprise
about 0.001 to about 50 weight percent aromatic triazole corrosion irhibitor.
The aromatic triazole corrosion inhibitor is used in an amount sufficient to
effectively prevent corrosion of the copper plated or metallized surfaces and circuitry
1 5 of semiconductor devices without overdosing with inhibitor which then must be
subsequently removed from the water. The dosage used is typically from about 1 ppm
to about 1,000 ppm. preferably from about 10 ppm to about 1,000 ppm and more
preferably from about 100 ppm to about 500 ppm.
The amount of aromatic triazole corrosion inhibitor in the aqueous treating
20 fluid is monitored iluorometrically and additional inhibitor is added to the fluid to
ensure that the aromatic triazole concentration b the fluid remains within the effective
range as described above. The fluorimetric method is described briefly as follows.
The fluorescence inrensity of the aqueous fluid using an excitation tight source
at the- desired omission wavelength, is measured with a detector capable of measuring
25 fluoresecont light. Suitable excitation light sources include light sources capable of
excitation liglit sources include xenon flashlamps, continuous xenon lamps, lunggten-
halogen lamps, deuterium lamps, deuterium-tungsten lamps, mercury vapor lamps,
phosphor-coatsd mercury vapor lamps, mercury-argon lamps and the like.
30 Acceptable detectors include, among others, photodiodes, photo transistors,
photocells, photovoltaic cells, photoitiultipIier tubes, charge-coupled devices and the
like. The detedor is selected based on its ability to detect light at the desired
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WO 2005/015608 PCT/US2004/017977
wavelength. Excitation and light sources and detectors are well kown in the art and
are commercially available from a variety of sources.
The measured fluorescence intensity is then compared to a working curve
drawn up using standards in ths concentration range of interest and this comparison
5 provides a precise determination of the concentration of the corrosion inhibitor in the
water sample drawn from the system
Proper choice of excitation arid emission "wavelengths are essential to obtaining
linearity and predictable results for fluorescence response to a range of aromatic
trixzole dosages. Table l shows selection of the excitation awl emission wavelength
10 required to obtain a linear response for benzolriazole. If optical fillers are chosen
incorrectly, reduced linearity in fluorescence response over a narrower dosage range
will occur (see Examples A-C below). In examples A-C, significant curvature of
response curve st 100 ppm (due to non-optimal choice of optical filters) leads to higher
readings than actually are present and would result in underfeeding of triazole.
15 Example D is the best combination of excitation gnd emission wavelengths (leading to
the best linearity over a broad range of concentrations) of the four examples shown in
Table 1.
20 Table 1
Excitation Emission Benzotriazolc Dosage
Example Wavelength (run) Waveleneth (nm) 100 com reading*
A 307 370 127 ppm
25
8 310 370 115 ppm
C 315 370 106ppm
30 0 370 102.6 ppm
* Fluordmeter calibrated at 0 ppm = 0 (distilled water) and 1000 ppm benzotriazole =
1000. For perfect linearity, 100 ppm benzotriazle- dosage will read 100.
35 A working curve for benzotriazole (excitationi wavelength 320 XXX, emission
wavelength 370 nm) is shown in FIG. 1. Similar curves can be readily created for any

WO 2005/015608 PCT/US2004/017977
desired aromatic triable when the fluorescence analysis conditions (for example,,
excitation and emission wavelength) aie defined.
As shown above, the present fluorometric method requires the selection of an
excitation wavelength to activate fhe fluorescence process and an emission wavelength
5 at which the aromatic0 triazolc corrosion inhibitor's fluorescence intensity is to be
measured, which preferably is substantially free of interference from other species
present in the aqueous fluid being monitored. Undesirable interference may be
encountered when some other species has significant fluorescence emission about the
emission wavelength selected for monitoring (he given corrosion inhibitor.
10 The fluorescence behavior of benzotriazole at various pH values is shown in
Table 2. The pH is measured using an Orion pH meter (Model 290A, Orion Research,
inc., Boston, MA) calibrated with VWR Scientific Products (West Chester, PA)
Standard buffers at pH 4 (potassium hydrogen phthalate buffer) and pH 10 (sodium
biocarbonate/carbonate buffer). Benzotriazole solution is prepared by dissolving
1 5 powdered benzotriazole b 50 niL of isopropy! alcohol and then diluting to a volume of
1 L with distilled water (final solution 95/5 vol/voi water/isoprapyl alcohol). For a
1000 ppm benzcrtviazole solution, 1 g of benzotriazole is used to prepare 1 L of
solution.
20 Table 2
pH versus Benzotriazole Concentration
Bonzotriazole (ppm) pH
0 8.2
10 5.7
100 5.0
1000 5.0
As shown in Table 2. a broad range of benzotriazole concentrations (10-1000
25 ppm) have a pH range (5,0-5.7) which are within the preferred pll operating range (pH
2-8,) where pH has little or no effect on. benzotriazole fluorescence as shown in Table
3.
The data in Table 3 are generated using a research-grade spectrotluorometer
(Jobin Yvon-SPEX/ Instrument S.A.., Edison, NJ). The following equipment set-tip
30 conditions arc used: 0.3 cm X 1 cm rectangular cuvette; 280 run excitation wavelength:
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WO 2005/015608 PCT/US2004/017977
conditions and benzolriazole concentration once the necessary operating and analysis
conditions are properly understood, characterized, and chosen.
As indicated above for benzotriazole, obtaining acceptable results for
monitoring and control of aromatic triazole dosage for an application area can depend
5 on a complex combination of operating conditions and fluorescence analysis
conditions. The necessary operating and analysis conditions can be determined for
each individual aromatic triazole chemistry using the methods described above.
"file fluoronietric analysis described above is used lo determine the
concentration of aromatic triable corrosion inhibitor present the aqueous fluid so that
10 additional corrosion inhibitor can be added as required to maintain the effective
corrosion inhibiting concentration.
The analysis can be conducted inlermittanntiy. in which case a sample of the
aqueous fluid is removed from the system for analysis or alternatively, a
spectrofluorometer can be installed on-line for conducting die triazole analysis and
1 5 dosage control at the desired intervals or continuously
A dual monochromator soectrroXXXorometer be used for a fluoremetric
analysis conducted on an mtemritlctil basis and for on-line and/or continuous
fluorescence regulating. Portable or compact fluorometcrs equipped with, appropriate
excitation and emission filters and quartz flow through cells are commercially
20 available, for instance from Ondeo Naleo Company, Naperville, IL.
In a preferred aspect of this invention, tbe fluoTometric analysis ia conducted on
a continuous basis.
In another preferred embodiment, the fluorometer comprises monitoring and
control means for automatically and continuously monitoring the concentration of
25 aromatic Triazole corrosion inhibitor in 5he aqueous fluid and adjusting the
concentration of corrosion inhibitor as required to maintain the desired effective
corrosion XXX concentration
Tbe XXX and control means typically includes a fluorometer for
determining, the concentration of aromatic triazole corrosion inhibitor in the water as
30 described above, the flourometer including a transducer which generates an electrical
signal corresponding to the inhibitor concentration and a feedback controller (monitor)
connected to a fluid addition pump or valve for controlling the addition of arotnatic
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WO 2005/015608 PCT/US2004/017977
triazole corrosion inhibitor contained in a reservoir, the pump to be activated and
deactivated or the valve opened and closed, depending on a comparison of the
concentration of corrosion inhibitor in the fluid, represented by the voltage signal from
the transducer. to a voltage standard represenning par performance of treating agent.
5 Methods of continuous monitoring and control of chemical additives are
described in detail in U.S. Patent Nos. 4,992.380 and 5,435,969, incorporated by
reference.
A preferred fluorometer has xenon flashlamp light-source to provide a broad
continuous range of excitation/emission wavelengths from 200-2000 nm. Thu Xenon
10 flashlamp is preferably activated once-per-second.and the Duorometer takes a
fluorescence reading. Therefore response to changes in triazole dosage can start to
occur after each second.
The optical filters (excitation and emission wavelengths) are preferably
exchangeable in order to optimize the optical filters for the system being
15 monitored/controlled. A preferred excitation optical filter is about 320 nm. the
preferred emission optical filler is about 370 nm. Some flexibility in the optical
wavelength values is acceptable (for example about 280 to about 320 nm excitation
and about 360 to about 375 XXX emission wavelengths) depending on the concentration
range of aromatic triazole to be measured and controlled. Exchangeable optical fillet's
20 are available, for example, from Andover Corporation, Salem, NH.
Any type of detector may be suitably employed so long as it is sensitive in the
emission wavelength range of the desired aromatic triazole corrosion inhibitor. A
phutodiode detector is preferred.
The fluorometer may also include a thermocouple to provide temperature-
25 compensation for the offsets of temperature on the fluorescence of the fluid sample.
such compensation may be necessary if the temperature of die fluid sample changes
XXX as XXX atomatic triazoles such as triasole have a fairly lurge
XXX; coefficient.
The fluorometer preferably includes a series of alarms XXX determine when error
30 conditions such as high corrosion inhibitor concentration low corrosion inhibitor
concentration, fluid .addition pump on too long. low (low rate of sample, sample too
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WO 2005/015608 PCT/US2004/017977
hot, etc. have occurred. The alarms are associated with "failsafe" operation of dosage
control whereby dosage is controlled on a timed basis when an alarm occurs.
The monitoring and control means may also include an output recording device
or other register that generates a continuous record of triazole aromatic triazole
5 corrosion inhibitor concentration as a function of time.
A preferred monitoring and control means is the TRASAR® Xe-2 Controller,
available from Ondeo Nalco Company, Naperville, IL.
FIG. 3 shows an embodiment of this invention where the treatment bath 4 is
equipped with means 12 for fluorometrically monitoring and controlling the
10 concentration of aromatic triazole corrosion, inhibitors iD the treatment bath where the
monitoring and control means 12 are disposed along the fluid transfer: line 6. The
monitoring and control means 12 include a flowcell 15 that is installed in the fluid
transfer line 6 so that fluid circulating through the fluid transfer line 6 flows through
the flowcell 15.
15 A. prefected flowcell is a. hollow fused quartz cylinder (tube) with an inner
diameter (ID) of about 3 mm and outer-diameter (OD) of about 5 mm with a wall
thickness of about 1 mm. The fused quartz flowcell is about 8.5 cm long and has o-
rings around each end to seal the flowcell to the flowcell housing to ensure no leakage
of fluid from the sample being analyzed, light from the fluorescence exciation light
20 source shines through the flowcell and excites the aromatic triazole corrosion inhibitor
in the aqueous fluid- The fluorescent emission light then shines through ihe flowcell
and out to a detector
The control means generates a control signal, designated as a flashed line in
FIGS. 3 and 4, that activates a valve 3 or fluid addition pump (not shown) disposed
25 between the aromatic triazole corrosion inhibitor supply ruservoir 1 and treatment bath
4 The control means automatic ally activates and deacti vates the pump or opens and
closes the valve to add corrosion inhibitor to maintain its concentration in the fluid in
the desired XXX range.
Accordingly, in another aspect, this invention is a treatment bath for copper
30 plated or metallized semiconductor devices comprising an inlet, an outlet, a fluid
transfer line connecting said inlet and outlet for circulating aqueous fluid containing
one or more aromatic triazole corrosion inhibitors through said treatment bath and
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fluid transfer line and monitoring and conlrol means for fluorometrically determining
the contration of aromatic triazole corrosion inhibitor in the aqueous fluid, wherein
the monitoring and control means comprise a flowcell installed in the fluid transfer
line.
5 In a preferred aspect of this invention, the treatment bath. further comprising a
supply reservoir containing an aqueous solution of aromatic triazole corrosion inhibitor
and a valve or pump for controlling the addition of the aqueous solution of aromatic
XXX corrosion inhibitor to the treatment bath.
FIG 4. Shows an embodiment of this invention where the- monitoring and
10 control means 12 are disposed along a side-stream sample line 13 connected to a
treatment bath fluid transfer line 6 through a side-stream sample line 13 and pump 14.
p'ump 14 can be activated as necessary to provide a continuous or intermittant flow of
fluid through a flowcell 15 installed in the side-stream sample line 13.
Accordingly, in another aspect, this invention is a treatment bath for copper
1 5 placed or metallized seimiconductor devices comprising an inlet, an outlet, a. fluid
transfer line connecting said inlet aod said XXX for circulating an aqueous fluid
containing one or more aromatic trinzole corrosion inhibitors through said treatment;
bath and fluid transfer line, a side -stream sample line for removing a sample of
aqueous fluid from the fluid transfer line and monitoring and control means for
20 fluorometrically determining the concentration of aromatic triazole corrosion inhibitor
in ihe aqueous fluid ,wherein the monitoring and control means comprise a flowcell
installed in the side-stream sample line.
As discussed herein, the aqueous treating fluid used in. semiconductor device
manufacturing processes comprises ultrapure water. In orderly maintain the integrity
25 of the manufacturing process, it is imperative thai no impurities be released in to the
XXX treating fluid from the flowcell. The chemical compatibility of the
XXX flowcell of this invention with ultrapure water is shown in Table4.
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WO 2005/015603 PCT/US2004/017977
Table 4
Chemical Compatibility of Fluorometer Flowcell and
Piping with Ultrapure Water Applications
Composition of Ultra-Pure Water R.ecirculsted from
Reservoir thru Fluorometer Flowcell
Analyts Expressed as Initial(XXX) Final pXXXm Change in ppm after
(7 days) 7 days
Silica asSiO2 < 0.017 < 0.017 No change
Sodium asNa 0.02 0.017 -0.003
Calcium asCa 0.006 0.046 0.040
Magnesium asMg < 0.001 0.006 0.006
Barium asBa. < 0.020 < 0.020 No change
Chromium) asCr < 0.0001 < 0.001 No change
Copper asCu < 0.001 < 0.001 No change
Iron asFe 0.001 < 0.001 No change
Potassium AsK. < 0.030 < 0.030 No change
Manganese as Ma < 0.001 < 0.001 No change
Molybdenum as Mo 0.02 < 0.001 0.02 ppm
Nickel asNi < 0.00] < 0.001 No change
Lead asPb < 0.002 < 0.002 No change
Zinc asZn 0.002 0.012 0.010
Chloride as CI < 0.002 0.044 0.042
Nitrate as NO3 <0.004 <0.004 No change
Ortho-Phosphate asPO4 < 0.004 < 0.004 No change
Sulfate asSO4 0.012 0.023 0.011
Fluoride AsF < 0.002 < 0.002 No change

The data in Table 4 show that most of the substances analyzed in the ultra-pure
water show little or no change in composition after the ultrapure water is continuously
recirculated from a liquid reservoir tlirough the fluoromeier flowcell for an extended
period of time (7 days). In a few cases, the substances being analyzed decreased
10 slightly (for example, motybdate level decreased by 0.02 ppm during this test). The
concentration of only a few substances increased slightly during this study (for
example, magnesium increased by 0.006 ppm). These small increases in chemcial
concentration are not a concern for this application This demonstrates that the
fluoronicier flowcell and materials of construction art compatible with this application
15 in ultra-pure water.
Changes can be made in the compositionst. operation and arrengement of the
method of the invention described herein without departing from the concept and
scope of the invention as defined in the claims.
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CLAIMS
1. A method of inhibitiag, corrosion of copper plated or metallized
surfaces and circuitry in semiconductor devices immersed in an aqueous fluid ina
5 treatment bath comprising
i) adding to the aqueous fluid an effective corrosion inhibiting aount of
one of more aromatic triazole corrosion inhibitors:
ii) fluorametrically monitoring the concentration of aromatic triazole
corrosion inhibitors in the aqueous fluid; and
10 iii) adding additional XXX triazle corrosion inhibitor to the. aqueous
fluid to maintain an effective corrosion inhibiting concentration of the aromatic
triazole corrosion inhibitor in the aqueous fluid.
2. the method of claim I wherein the aromatic triazole corrosion
inhibitors are selected from the group consisting of benzotritriazole,
15 butylbcnzotritriazole, tolyltritriazole and naplithotritriazolc.
3. The method of claim 1 wherein the aromatic triazole corrosion inhibitor
is selected from the group consisting of beozotdazole, tolyltriazole and
XXX
4. The method of claim 1 wherein the effective corrosion inhibiting
20 amount of triazole corrosion inhibitor is from about 1 ppm to about 1T000 ppm.
5. The method of claim I wherein the effective corrosion inhibiting
amount of triazoie corrosion inhibitor is from about 10 ppm to about 1.000 ppm.
6. The method of claim 1 wherein the effective corrosion inhibiting
amount of triazole corrosion inhibitor is from about 100 ppm to about 500 ppm.
25 7. The method of claim 1 wherein the contration of triazole corrosion
inhibitor is measured intermittently
8. The method of claim I wherein the concentrarion of triazole corrosion
inhibitor is measurred continuously.
9. The method of claim 1 wheiein the treatment bath comprises an inlet,
30 an outlet, a fluid transfer line connecting said inlet and outlet for circulating the
aqueous fluid through said treatment bath and fluid transfer line and monitoring and
control means for fluorometrically determining the concentration of aromatic triazole
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corrosion inhibitor in the aqueous fluid, wherein the monitoring and control means
comprise a flowcell installed in the fluid transfer line.
10. The method of claim 9 wherein the monitoring is accomplished by
introducing a sample of the aqueous fluid from the treatment bath into the flowcell and
5 fluorometrically determining the concentration of the aromatic triazole corrosion
inhibitor in the aqueous fluid in the flowcell.
11. The method of claim 10 wherein the aqueous fluid is continuously
circubicd drrough the flowcell and the concentration of aqueous triable corrosion
inhibitor is monitored continuously or intermittently.
10 12. The method of claim 9 wherein the treatment bath further comprises a
supply reservoir containing an aqueous solution of aromatic triazole corrosion inhibitor
and a valve or pump for controlling the addition of the aqueous solution of aromatic
triazole corrosion inhibitor to the treatment bath.
13. The method of claim 12 wherein the- monitoring and control means
15 comprises a fluorometer for determining the concentration of aromatic triazole
corrosion inhibitor in the aqueous fluid and a controller in communication with the
valve or pump wherein the controller activates or deactivates the pump or opens or
CLOSES the valve based on the contration of the aqueous aromatic corrosion inhibitor
in the aqueous fluid.
20 14. The method of claim 1 wherein the treatment bath comprises an inlet,
an outler, a fluid transfer line connecting said inlet aad Outlet for circulating the
aqueous fluid through said treatment bath and fluid transfer line, a side-stream sample
line for removing, a sample of aqueous fluid, from. the fluid transfer line and monitoring
and control means for fluoronietrically deternining the concentration of aromatic
25 triazole corrosion inhibitror in the aqueous fluid, wherein the monitoring and control
means comprise a flowcell installed in the side-stream sample line
15. The method of claim 14 wherein ihe monitoring is accomplished by
introducing a sample of the aqueous fluid from the treatment bath into the flowcell and
fluorometrically determining the concentration of the aromatic triazole corrosion
30 inhibitor in lhe aqueous fluid in the flowcell.
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WO 2005/015608 PCT/US2004/017977
16. The method of claim 14 wnerein the treatment bath further comprises 3
supply reservoir containing an aqueous solution of aromatic triazote corrosion inhibitor
and a valve or pump for controlling the addition of the aqueous solution of aromatic
triazole corrosion inhibitor to the treatment bath.
5 17. The method of claim 16 wherein the monitoring and control means
comprises a fluoro meter for determining the concentration of aromatic triazole
corrosion inhibitor in the aqueous fluid and a controller in communication with the
valve or pump wherein the controller activates ot deactivates its pump or opens or
closes the valve based on the concentration of the aqueous aromatic corrosion inhibitor
10 in the aqueous fluid.
18. A treatment bath for copper plated or metallized semiconductor devices
comprising an Inlet, an outlet, a fluid transfer line connecting said inlet and outlet for
circulating aqueous fluid containing one or more aromatic triazole corrosion inhibitors
through said treatment bath and fluid transfer line and monitoring and control means
15 for fluorometrically determining the concentration of aromatic triazole corrosion
inhibitor in the aqueous fluid, wherein the monitoring and control means comprise a
flowcell installed in the fluid transfer line.
19. Ths treatment bath according to claim 9 further comprising a supply
reservoir containing an aqaeous solution of aromatic triable corrosion inhibitor and a
20 valve or pump for controlling the addition of the aqueous solution of aromatic triazole
corrosion inhibitor to the treatment bath.
20 A treatment bath for copper plated or metallised semiconductor devices
comprising an inlet, an outlet, a fluid transfer lino connecting said inlet and said outlet
for circulating an aqueous fluid containing one or more aromatic triazole corrosion
25 inhibitors through said treatment bath and fluid transfer line, a side-stream sample line
for removing a sample of aqueous fluid from lhe fluid transfer line and monitoring and
control means for fluorometricaily determining the concentration of aromatic triazole
corrosion inhibitor in the aqueous fluid, wherein line monitoring and control means
comprise a flowcell instated in the side-stream sample line.
30 21. The treatment bath according to claim 20 further comprising, a supply
reservoir containing an aqueous solution, of aromatic triazole corrosion inhibitor and a
17

WO 2005/015608 PCT/US2004/017977
valve or pump for controlling the addition of the aqueous solution of aromatic triazole
corrosion inhibitor to the treatment bath.

A treatment bath for use in the. manufacture of copper plated or metallized semiconductor davices and a method
of inhibiting corrosion of copper plated or matalized surfaces and circuitry in the semiconductor devices immersed in an aqoeous
fluid in a treatment bath comprising adding to the aqueous fluid an effective corrosion inhibiting amount of one or more aromatic
triazole corrosion inhibitors; XXXmetrically monitoring the concentration of aromatic triazole corrosion inhibitors in the aqueous
fluid; and adding additional aromatic triazole corrosion inhibitor to the aqueous fluid to maintain an effective corrosion inhibiting
conceniration of thc aromatic triazole corrosion inhibitor in the aqueous fluid