US 20130032296Al
(19)
United States
(12) Patent Application Publication (10) Pub. N0.: US 2013/0032296 A1
Zhong
(54)
(43) Pub. Date:
CLEANING COMPOSITION FOR
TEMPORARY WAFER BONDING
MATERIALS
C11D 7/60
B08B 3/00
(52)
Feb. 7, 2013
(2006.01)
(2006.01)
US. Cl. ........ .. 156/704; 134/26; 428/704; 510/175;
5 10/200
(75) Inventor: Xing-Fu Zhong, Rolla, MO (U S)
(57)
(73)
Assignee:
BREWER SCIENCE INC., Rolla, MO
(Us)
Aug, 2, 2011
Publication Classi?cation
(51) Int. C1.
B32B 38/10
B32B 9/04
(2006.01)
(2006.01)
I
m
_ _
_
cleaning compositlon for removing temporary Wafer bond
1ng mater1al is provided. The cleaning compos1t1on comprises
an alkylarylsulfonic acid and an aliphatic alcohol dispersed or
dissolved in a hydrocarbon solvent system. Methods of sepa
(21) App1_ NO; 13/196,679
(22) Filed;
ABSTRACT
_
rating bonded substrates and cleaning debonded substrates
using the cleaning composition are also provided. The inven
tion is particularly useful for temporary bonding materials
and adhesives. The methods generally comprise contacting
the bonding material With the cleaning solution for time peri
ods su?icient to dissolve the desired amount of bonding mate
rial for separation and/ or cleaning of the substrates.
Patent Application Publication
Feb. 7, 2013 Sheet 1 of3
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Feb. 7, 2013
US 2013/0032296 A1
CLEANING COMPOSITION FOR
TEMPORARY WAFER BONDING
MATERIALS
BACKGROUND OF THE INVENTION
[0001]
[0002]
1. Field of the Invention
The present invention relates to cleaning methods
and compositions for debonding and/or cleaning debonded
substrates, such as substrates used in temporary Wafer bond
alkylarylsulfonic acid and an aliphatic alcohol dispersed or
dissolved in a hydrocarbon solvent system.
[0011] In a further aspect, a method of removing a bonding
material from a substrate is provided. The method comprises
providing a stack comprising ?rst and second substrates
bonded together via a layer of a bonding material; and con
tacting the bonding material With a cleaning composition to
thereby remove at least a portion of the layer of bonding
material. The cleaning composition comprises an alkylaryl
ing processes.
[0003] 2. Description of RelatedArt
[0004] During the manufacture of three-dimensional (3-D)
sulfonic acid and an aliphatic alcohol dispersed or dissolved
in a hydrocarbon solvent system.
[0012] In yet another aspect of the invention, there is pro
integrated semiconductor microcircuits, it is often necessary
vided a microelectronic structure. The structure comprises a
to temporarily bond a device Wafer to a carrier Wafer With an
adhesive so that the device Wafer can undergo grinding, thin
substrate having a surface; a quantity of bonding material
adjacent the substrate surface; and a cleaning composition
ning, photolithography, chemical vapor deposition (CVD),
adjacent the bonding material. The cleaning composition
and/ or other processes. After all the necessary processing
steps are completed, the device Wafer is then separated, or
debonded, from the carrier Wafer. Debonding of a device
Wafer from the carrier folloWing backside processing can be
comprises an alkylarylsulfonic acid and an aliphatic alcohol
dispersed or dissolved in a hydrocarbon solvent.
[0013] In a further aspect, a cleaning composition for
typically performed by various processes such as:
[0005] (l) ChemicaliThe bonded Wafer stack is immersed
removing temporary Wafer bonding material is provided. The
cleaning composition comprises an alkylarylsulfonic acid
in, or sprayed With, a solvent or chemical agent to dissolve or
and an aliphatic alcohol dispersed or dissolved in a hydrocar
bon solvent.
decompose the bonding material.
[0006] (2) PhotodecompositioniThe bonded Wafer stack
BRIEF DESCRIPTION OF THE DRAWINGS
is irradiated With a light source through a transparent carrier
to photodecompose the bonding material adjacent to the car
[0014]
rier.
Wafer stack in accordance With the invention;
[0007] (3) ThermomechanicaliThe bonded Wafer stack is
heated above the softening temperature of the bonding mate
rial, and the device Wafer is then slid, pulled, or peeled aWay
from the carrier While being supported With a full-Wafer hold
ing chuck.
[0008] (4) ThermodecompositioniThe bonded Wafer
stack is heated above the decomposition temperature of the
bonding material, causing it to volatiliZe and lose adhesion to
the device Wafer and carrier.
[0015]
FIG. 1(a) is a schematic cross-sectional vieW of a
FIG. 1(b) is a schematic cross-sectional vieW of a
debonded Wafer stack of FIG. 1(a);
[0016]
FIG. 2(a) is a schematic cross-sectional vieW of a
further Wafer stack embodiment of the invention;
[0017] FIG. 2(b) is a schematic cross-sectional vieW of the
Wafer stack from FIG. 2(a) after edge removal;
[0018]
FIG. 3(a) is a schematic cross-sectional vieW of a
[0009] Regardless of the method, residual bonding material
further Wafer stack embodiment of the invention;
[0019] FIG. 3(b) is a schematic cross-sectional vieW of the
must generally be cleaned from the device Wafer prior to the
Wafer stack from FIG. 3(a) after edge removal; and
next processing step. Furthermore, sometimes-expensive car
rier Wafers must be cleaned for reuse. Conventional hydro
carbon solvents that dissolve the temporary adhesives do not
clean effectively because they leave too much residue, as do
conventional solvents used for chemical separation of the
substrates in the ?rst place. Strong acidic or alkaline solutions
such as concentrated sulfuric acid/hydrogen peroxide (Nano
Strip or Piranha solution) and RCA cleaning solutions may
effectively clean the Wafers, but they are corrosive and can
attack metallic circuits or pads. Thus, there remains a need in
the art for improved cleaning solutions for separating and
cleaning temporarily bonded substrates.
SUMMARY OF THE INVENTION
[0010]
The present invention is broadly concerned With
methods of removing bonding materials from a substrate and
compositions useful for removing bonding materials or adhe
sives, especially temporary Wafer bonding materials. In one
aspect, there is provided a method of cleaning a substrate
surface. The method comprises providing a substrate having
a surface With a bonding material thereon and contacting the
bonding material With a cleaning composition to thereby
remove at least a portion of the bonding material from the
substrate surface. The cleaning composition comprises an
[0020]
FIG. 4 is a schematic cross-sectional vieW of a Wafer
stack after edge removal.
[0021] While the draWings illustrate, and the speci?cation
describes, certain preferred embodiments of the invention, it
is to be understood that such disclosure is by Way of example
only. Embodiments of the present invention are described
herein With reference to cross-section illustrations that are
schematic illustrations of idealiZed embodiments of the
present invention. As such, variations from the shapes of the
illustrations as a result of for example, manufacturing tech
niques and/ or tolerances, are to be expected. There is no intent
to limit the principles of the present invention to the particular
disclosed embodiments. For example, in the draWings, the
siZe and relative siZes of layers and regions may be exagger
ated for clarity and are not shoWn to scale. In addition,
embodiments of the present invention should not be con
strued as limited to the particular shapes of regions illustrated
herein but are to include deviations in shapes that result, for
example, from manufacturing. For example, a topographical
region illustrated as a rectangle may have rounded or curved
features. Thus, the regions illustrated in the ?gures are sche
matic in nature and their shapes are not intended to illustrate
the precise shape of a region of a device and are not intended
to limit the scope of the present invention.
Feb. 7, 2013
US 2013/0032296 A1
DETAILED DESCRIPTION
[0022]
In more detail, the present invention is concerned
With neW cleaning solutions and cleaning methods, especially
suited for removing temporary Wafer bonding materials from
microelectronic substrates. The cleaning composition com
prises an alkylarylsulfonic acid and an aliphatic alcohol dis
persed or dissolved in a hydrocarbon solvent system. Suitable
alkylarylsulfonic acids for use in the invention Will include
C 1 -C 1 8 alkyl groups, but preferably contain longer chain alkyl
groups such as C6-Cl8alkyls, and more preferably CS-Cl2
hydrocarbon solvents Will preferably have a ?ash point of
greater than about 1000 F. Particularly preferred hydrocarbon
solvents for use in the invention are selected from the group
consisting of saturated hydrocarbon solvents and aromatic
hydrocarbon solvents. The hydrocarbon solvent is preferably
present in the composition at a level of from about 70% to
about 96% by Weight, more preferably from about 80% to
about 94% by Weight, and even more preferably from about
80% to about 90% by Weight, based upon the total Weight of
the composition taken as 100% by Weight.
alkyls. Suitable alkylarylsulfonic acids Will also include
C6-C22 aryls, more preferably C6-Cl6 aryls, and even more
[0026] The composition is formed by mixing the alkylar
ylsulfonic acid, aliphatic alcohol, and hydrocarbon solvent
preferably C6-Cl0 aryls. Exemplary aryl groups are selected
from the group consisting of benZene, naphthalene, and
anthracene, With alkylbenZenesulfonic acid being particu
temperature ~20° C. and 14.7 psi). More preferably, the com
larly preferred. Speci?c examples of suitable alkylbenZene
sulfonic acids include those selected from the group consist
ing of hexylbenZenesulfonic acid, heptylbenZenesulfonic
acid, octylbenZenesulfonic acid, decylbenZenesulfonic acid,
dodecylbenZenesulfonic acid, tridecylbenZenesulfonic acid,
tetradecylbenZenesulfonic acid, hexadecylbenZenesulfonic
acid, and octadecylbenZenesulfonic acid. Mixtures of tWo or
more alkylarylsulfonic acids could also be used in the inven
tive compositions. The composition preferably comprises
from about 2% to about 15% by Weight alkylarylsulfonic
acid, more preferably from about 3% to about 10% by Weight
together, preferably under ambient conditions (i.e., room
position is formed by ?rst dissolving the alkylarylsulfonic
acid in the aliphatic alcohol to form a true (i.e., molecular)
solution. Next, the hydrocarbon solvent is sloWly added to the
solution With vigorous stirring, preferably until the alkylar
ylsulfonic acid changes from solution form to reverse micelle
form. More speci?cally, the hydrocarbon solvent is prefer
ably added until the ratio of hydrocarbon solvent to aliphatic
alcohol is at least about 1 :1, preferably greater than about 5:1,
and more preferably greater than about 15:1. Though not
Wishing to be bound by theory, the reverse micelles are
believed to be characterized by sulfonic acid groups in the
core and alkylaryl groups in the shell/ corona. The concentra
alkylarylsulfonic acid, and even more preferably from about
tion of aliphatic alcohol is also believed to be greater inside
5% to about 10% by Weight alkylarylsulfonic acid, based
upon the total Weight of the composition taken as 100% by
the reverse micelles (i.e., in the core and at the interface
betWeen the core and corona) than outside the reverse
Weight.
[0023]
Suitable aliphatic alcohols for use in the inventive
micelles.
[0027]
Although other ingredients may be included in the
compositions include Cl-C8 aliphatic alcohols, preferably
cleaning compositions (such as ketones, alkyl halides, fatty
C 1 -C6 aliphatic alcohols, and more preferably C2-C4 aliphatic
acids, and mixtures thereof), it is preferred that the composi
tion consist essentially (or even consist) of alkylarylsulfonic
acid, aliphatic alcohol, and hydrocarbon solvent. That is, the
compositions are preferably substantially free of any other
ingredients. More speci?cally, it is preferred that the compo
alcohols. Exemplary aliphatic alcohols for use in the inven
tive composition include those selected from the group con
sisting of ethanol, 1-propanol, 2-propanol (isopropanol),
1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2
propanol, allyl alcohol, 2-butyn-1-ol, 3-butyn-1-ol, 3-butyn
2-ol, 3-buten-1-ol, 3-buten-2-ol, 1-pentanol, 2-pentanol, and
1-hexanol. Mixtures of tWo or more aliphatic alcohols could
also be used in the inventive compositions. The composition
preferably comprises from about 2% to about 15% by Weight
aliphatic alcohol, more preferably from about 3% to about
10% by Weight aliphatic alcohol, and even more preferably
from about 5% to about 10% by Weight aliphatic alcohol,
based upon the total Weight of the composition taken as 100%
sitions be substantially free of halides, such as ?uoride, chlo
ride, etc. It is also preferred that the compositions be substan
tially free of alkoxybenZenes. The compositions are also
substantially free of anisole. It is also preferred that the com
positions be substantially free of any corrosive materials,
such as strong acid or alkaline solutions (e.g., sulfuric acid,
hydrogen peroxide, sodium hydroxide, potassium hydroxide,
or tetramethyl ammonium hydroxide). The composition is
also preferably substantially free of surfactants, such as
by Weight.
sodium dodecyl sulfate (SDS), polyethylene glycol tert-oc
[0024]
tylphenyl ether (Triton X-100), and PC4430. It is also pre
ferred that the compositions be substantially free of phenol.
Suitable hydrocarbon solvents for use as the solvent
system include C6-Cl6 hydrocarbon solvents, C6-Cl2 hydro
carbon solvents, and CS-Cl2 hydrocarbon solvents, With
C8-C1, hydrocarbon solvents being particularly preferred.
The term “substantially free,” as used herein, means that the
ingredient is present in the composition at a level of less than
With its customary meaning as indicating liquid compounds
about 0.5% by Weight, more preferably less than about 0.1%
by Weight, and even more preferably about 0% by Weight,
consisting entirely of hydrogen and carbon (and excluding
based upon the total Weight of the composition taken as 100%
The term “hydrocarbon solvent” is used herein in accordance
compounds that contain other elements, such as oxygen or
by Weight.
nitrogen). Examples of suitable hydrocarbon solvents include
those selected from the group consisting of hexane, cyclohex
ane, heptane, octane, 1-octene, decane, 1-decene, dodecane,
temporary Wafer bonding material from various substrates,
1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene,
toluene, xylene, mesitylene, decahydronaphthalene (Deca
lin), 1,2,3,4-tetrahydronaphthalene (Tetralin), naphtha, ethyl
[0028]
The cleaning composition can be used to remove
such as microelectronic substrates. For example, the cleaning
composition can be used to clean residual Wafer bonding
material from one or both substrates after separation, and/or
Mixtures of tWo or more hydrocarbon solvents
the cleaning composition can be used to dissolve the Wafer
bonding material to facilitate separation of the bonded sub
strates in the ?rst place. In a typical method of use, a Wafer
could also be used in the inventive compositions. Preferred
stack is provided. The stack comprises bonded substrates, and
benZene, cumene, and limonene.
[0025]
Feb. 7, 2013
US 2013/0032296 A1
in particular, a ?rst substrate bonded to a second substrate via
a layer of bonding material. After processing, the ?rst and
second substrates are separated, for example, using the inven
tive cleaning composition and/ or another suitable separation
method described above. The separated substrates are then
that it ?oWs into and over the various topographical features
20a-20d. The substrates 12, 14 are then bonded in face-to
face relationship to one another. Exemplary bonding materi
als include commercial temporary Wafer bonding composi
tions such as those sold under the name WaferBOND®
cleaned of residual bonding material using the inventive
(available from BreWer Science Inc., Rolla, Mo.), some com
cleaning composition.
mercial photoresist compositions, and other resins and poly
[0029]
mers that exhibit high adhesion strength to semiconductor
More speci?cally, FIG. 1(a) depicts one embodi
ment of a stack 10 of tWo reversably bonded Wafers. The
exemplary stack 10 comprises a ?rst substrate 12 and a sec
materials, glass, and metals. Especially preferred bonding
ond substrate 14. In the embodiment depicted in FIG. 1(a),
materials are: (1) high solids, UV-curable resin systems such
as reactive epoxies and acrylics; (2) related thermosetting
the ?rst substrate 12 is an active or device Wafer having a back
resin systems such as tWo-part epoxy and silicone adhesives;
surface 16, an outermost edge 17 de?ning the periphery (pe
rimeter) of the substrate 12, and a device surface 18, Which
can comprise various topographical features 20a-20d. As
used herein, “topography” refers to the height or depth of a
(3) thermoplastic acrylic, styrenic, vinyl halide (non-?uoro
containing), and vinyl ester polymers and copolymers along
structure in or on a substrate surface. Typical ?rst substrates
With polyamides, polyimides, polysulfones, polyethersul
fones, and polyurethanes; and (4) cyclic ole?ns, polyole?ns
(e.g., polyisobutylene, polyisoprene, polyhydrocarbon), and
12 can include any microelectronic substrate. Exemplary ?rst
substrates 12 in this embodiment include those is selected
hydrocarbon-based tacki?er resins. Regardless of the
embodiment, the bonding layer 24 is bonded to device surface
from the group consisting of microelectromechanical system
18 of substrate 12 as Well as to bonding surface 22 of substrate
(MEMS) devices, display devices, ?exible substrates (e.g.,
14, as shoWn in the FIG. 1(a)
[0032] The bonding layer 24 can be a uniform (chemically
cured epoxy substrates, roll-up substrates that can be used to
form maps), compound semiconductors, loW k dielectric lay
ers, dielectric layers (e.g., silicon oxide, silicon nitride), ion
implant layers, and substrates comprising silicon, aluminum,
the same) material across its thickness and/or across the sub
strate surfaces 18, 22, as shoWn in FIG. 1(a). Alternatively,
there can be a non-uniform material distribution across the
tungsten, tungsten silicide, gallium arsenide, germanium,
substrates or across the thickness of the layer, as depicted in
tantalum, tantalum nitrite, SiGe, and mixtures of the forego
the Wafer stacks of FIGS. 2(a) and 3(a), With like numbering
being used for like parts. For example, a portion of the bond
ing layer 24 may include ?ll material 28. It Will be appreciated
that the bonding strength of the ?ll material 28 Will depend
upon its speci?c chemical structures and the coating and
baking conditions used to apply it; hoWever, the ?ll material
28 generally does not form strong (or as strong of) adhesive
ing. The device surfaces 18 can also comprise arrays of
devices selected from the group consisting of integrated cir
cuits, MEMS, microsensors, poWer semiconductors, light
emitting diodes, photonic circuits, interposers, embedded
passive devices, and other microdevices fabricated on or from
silicon and other semiconducting materials such as silicon
germanium, gallium arsenide, and gallium nitride. The sur
faces of these devices also commonly comprise structures
formed from one or more of the folloWing materials: silicon,
polysilicon, silicon dioxide, silicon (oxy)nitride, metals (e.g.,
copper, aluminum, gold, tungsten, tantalum), loW-k dielec
bonds as the bonding material. Such ?ll material 28 is typi
cally formed of a material comprising monomers, oligomers,
and/or polymers dispersed or dissolved in a solvent system.
Examples of suitable monomers, oligomers, and/ or polymers
include those selected from the group consisting of cyclic
trics, polymer dielectrics, and various metal nitrides and sili
ole?n polymers and copolymers and amorphous ?uoropoly
cides. The device surface 18 can also include raised structures
mers With high atomic ?uorine content (greater than about
30% by Weight) such as ?uorinated siloxane polymers, ?u
such as solder bumps and metal posts and pillars.
[0030] The second substrate 14 in the illustrated embodi
orinated ethylene-propylene copolymers, polymers, With
ment is a carrier Wafer. The second substrate 14 has a bonding
pendant per?uoroalkoxy groups, and copolymers of tet
surface 22 and an outermost edge 23 de?ning the periphery
(perimeter) of the substrate 14. Typical carrier substrates 14
can comprise a material selected from the group consisting of
ra?uoroethylene and 2,2-bis-tri?uoromethyl-4,5-di?uoro-1,
3-dioxole being particularly preferred.
sapphire, ceramic, glass, quartz, metals (e.g., aluminum, cop
per, steel, silver), silicon, various glasses and ceramics, glass
various temporary bonding materials and ?ll materials are
disclosed in Us. Pat. App. Pub. No. 2009/0218560, ?led Jan.
ceramic composites (such as products sold under the name
Zerodur®; available from Schott AG), and combinations
thereof. The second substrate 14 can also include other mate
23, 2009, Us. Pat. App. Pub. No. 2008/0200011, ?led Jun.
14, 2007, Us. Pat. App. Pub. No. 2009/0218560, Jan. 23,
2009, and Us. Pat. App. Pub. No. 2010/0112305, Oct. 31,
rials deposited on its surface 22 (not shoWn). For example,
2008, as Well as inU.S. Pat. No. 7,713,835, ?led Oct. 3, 2007,
silicon nitride can be deposited onto a silicon Wafer to change
and Us. Pat. No. 7,935,780, ?led Jun. 25, 2008, and copend
ing U.S. Ser. No. 12/819,680, ?led Jun. 21, 2010, the disclo
the bonding characteristics of the surface 22.
[0031]
The ?rst substrate 12 and second substrate 14 are
bonded together via a layer 24 of bonding material. Bonding
layer 24 can be formed from any suitable bonding material,
and is preferably formed from a temporary bonding compo
sition. The perimeter of the bonding layer 24 is de?ned by an
outermost edge 26. It Will be appreciated that the bonding
layer 24 can be applied to either or both substrates 12, 14,
such as by spin-coating or spray-coating. In embodiments
Where the ?rst substrate 12 comprises topography, the bond
ing material is preferably applied to the ?rst substrate 12 so
[0033]
Exemplary methods of forming Wafer stacks and
sures of Which are incorporated by reference herein in their
entirety to the extent not inconsistent With the present appli
cation. It Will be appreciated, hoWever, that the order of
assembling or applying the components to form the Wafer
stack Will vary, and can be performed in any order or using
any method suitable to achieving a stack comprising bonded
substrates. It Will also be appreciated that FIGS. 1-3 are
provided by Way of illustration only and do not represent the
only type of Wafer stacks suitable for use With the present
invention.
Feb. 7, 2013
US 2013/0032296 A1
[0034]
After the desired processing has occurred, the ?rst
substrate 12 can be separated from the second substrate 14, as
shoWn in FIG. 1(b). Various methods can be used to separate
the bonded substrates 12, 14, as described above. For
to dissolve the desired amount of bonding material and/ or ?ll
material to achieve the desired distance “D.”
[0037] Other removal processes include ?rst mechanically
disrupting or destroying the continuity of the outermost por
example, in one preferred embodiment, the ?rst substrate 12
tion of the bonding layer 24 using laser ablation, plasma
and second substrate 14 are separated by heating to a tem
etching, Water jetting, or other high energy techniques that
effectively etch or decompose the edge. It is also suitable to
perature suf?cient to soften the bonding layer 24. In another
preferred embodiment, instead of heating to soften the layer
24, the bonding material can be dissolved using the inventive
cleaning composition itself. The cleaning composition of the
invention can be used to dissolve the entire layer 24 of bond
ing material or only a portion thereof. Dissolution of the
entire layer 24 of bonding material can be achieved by con
tacting the bonding layer 24 With the cleaning composition.
The composition can be spin-applied, sprayed, or otherWise
dispensed onto the outermost edge 26 of the layer 24, or the
Wafer stack 10 can be immersed in the cleaning composition.
Contact With the composition is carried out until the layer 24
is suf?ciently dissolved to facilitate separation of the sub
strates 12, 14. In general, the bonding material may be con
tacted With the cleaning solution for time periods of from
about 30 seconds to about 12 hours, preferably from about 1
min. to about 60 min., more preferably from about 5 min. to
about 30 min., and even more preferably from about 10 min.
to about 20 min. Contact is preferably carried out at tempera
tures of from about 20° C. to about 80° C., more preferably
from about 30° C. to about 60° C., and even more preferably
from about 40° C. to about 50° C. The substrates 12, 14 can
then be separated, and residual bonding material can be
removed from the substrate(s) if necessary, as described
beloW.
[0035] In an alternative embodiment, the cleaning compo
sition can be used to dissolve only a portion of the layer 24 of
?rst saW or cut through the outermost portion of the bonding
layer 24 or cleave the layer 24 by some equivalent means.
Regardless of Which of the above means is utiliZed, the sub
strates 12, 14 can then be separated, preferably using a loW
mechanical force (e.g., ?nger pressure, gentle Wedging) to
slide, lift, peel, or otherWise remove the ?rst substrate 12 from
the second substrate 14. Tools and implements can also be
used to facilitate separation, such as clamps, vacuum chuck,
?exible chuck, adhesive ?lm-covered chuck, and the like,
Which are knoWn in the art.
[0038] It Will be appreciated that the particular process used
for separation Will depend upon the chemical make-up of the
bonding layer 24, as Well as the physical con?guration of the
layer 24 (i.e., uniform vs. non-uniform). It Will also be appre
ciated that the time required to suf?ciently dissolve the bond
ing layer When using the cleaning composition of the inven
tion Will depend, to an extent, on the chemical composition of
the bonding material and the methods used to apply it.
Removal With the inventive cleaning compositions can also
be used in combination With heat as described above and/or
any other processes suitable for facilitating separation of the
substrates.
[0039] Regardless of the process used to separate the sub
strates 12, 14, the debonded surfaces of the substrates Will
generally comprise residual bonding material 24', as shoWn in
FIG. 1(b). Depending upon the method used to separate the
substrates 12, 14, the residual bonding material 24' can be in
bonding material, such as only the outermost portion of the
bonding layer 24, as shoWn in FIG. 4. This can be achieved by
the form of a layer on the substrate surface, or it can be in the
dispensing the cleaning composition only along the outer
herein to refer to the presence of bonding material on the
most edge 26 of the layer 24, using, for example, a spinning or
spraying application method. This process is carried out until
the desired portion of the layer 24 is removed, preferably for
about 30 seconds to about 20 min., more preferably from
about 1 min. to about 10 min., and even more preferably from
about 2 min. to about 5 min. Alternatively, the Wafer stack can
be immersed into the cleaning composition for a speci?c
period of time (typically from about 2 min. to about 120 min.,
more preferably from about 3 min. to about 20 min., and even
more preferably from about 5 min. to about 10 min.) to
dissolve only the outermost portion of the bonding layer 24.
Regardless of the embodiment, the stack is then preferably
rinsed and spun dry, as described beloW. Such edge removal
can be used With any of the bonding/debonding methods
described above, but is particularly suited for use With non
uniform bonding layers 24 as shoWn in FIGS. 2(a) and 3(a).
FIGS. 2(b) and 3(b) depict the respective Wafer stacks after
edge removal.
form of bonding material residue. The term “residue” is used
surface of the ?rst substrate 12 and/or second substrate 14,
Wherein the bonding material covers less than 100% of the
surface area of the substrate surface. In other Words, the
bonding material is not present as an intact layer adjacent the
substrate surface, but covers only portions of the surface. The
residual bonding material 24' can be cleaned from the ?rst
substrate 12 and/or second substrate 14 using the inventive
cleaning composition. In general, this is accomplished by
contacting the residual bonding material 24' on the substrate
With the cleaning composition for a time period su?icient to
dissolve aWay the material.
[0040] In one aspect, the substrate(s) can be cleaned by a
spin application method. In this aspect, the cleaning compo
sition is spin-applied continuously at about 200 to about
1,200 rpm (preferably about 300 to about 1,000 rpm, and
more preferably about 300 to about 600 rpm) to the spinning
substrate for about 1 to about 10 minutes (preferably about 1
to about 8 min., and more preferably about 2 to about 5 min.).
[0036] In embodiments using edge removal, the bonding
Alternatively, the cleaning composition is spin-applied inter
layer 24 or ?ll material 28, as the case may be, has an outer
mittently at about 200 to about 1,200 rpm (preferably about
most edge 30, Which is spaced a distance “D” from the plane
de?ned by the outer edge 17 of the ?rst substrate 12, as shoWn
in FIGS. 2(1)), 3(1)), and 4. “D” is typically from about 0.05
300 to about 1,000 rpm, and more preferably about 500 to
about 800 rpm) With a frequency of about 1 to about 6 cycles/
min. (preferably about 1 to about 4 cycles/min., and more
preferably about 1 to about 3 cycles/min.) for about 2 to about
5 minutes (preferably about 2 to about 4 min., and more
mm to about 10 mm, more preferably from about 0.5 mm to
about 5 mm, and even more preferably from about 1 mm to
about 2.5 mm. It Will be appreciated that contact With the
cleaning composition can be maintained for a suf?cient time
preferably about 2 to about 3 min.). This is folloWed by
spin-rinsing the substrate With a solvent at about 200 to about
Feb. 7, 2013
US 2013/0032296 A1
1,200 rpm (preferably about 500 to about 1,000 rpm, and
EXAMPLES
more preferably about 600 to about 900 rpm) for about 30 to
about 60 seconds (preferably about 30 to about 50 seconds,
and more preferably about 30 to about 40 seconds), and then
[0043] The folloWing examples set forth methods in accor
dance With the invention. It is to be understood, hoWever, that
these examples are provided by Way of illustration and noth
spin drying rapidly at about 1,500 to about 2,000 rpm for
about 30 to about 60 seconds (preferably about 30 to about 50
seconds, and more preferably about 30 to about 40 seconds).
Suitable solvents for rinsing are selected from the group
ing therein should be taken as a limitation upon the overall
scope of the invention.
Example 1
consisting of Water, isopropanol, 1-dodecene, acetone,
methanol, ethanol, and mixtures thereof. In a further aspect,
the substrate(s) can be cleaned by a puddling method. In this
aspect, the cleaning composition is puddled onto the substrate
Wafer Cleaning With Inventive Cleaning Solution
1. Preparation of Cleaning Solution Formulation A
surface and alloWed to remain for about 2 to about 120 sec
[0044]
onds (preferably about 30 to about 90 seconds, and more
preferably about 45 to about 60 seconds). The cleaning com
position is then spun off at about 500 to about 2,000 rpm
dodccylbenZenesulfonic acid in isopropanol (Aldrich, Mil
To prepare a cleaning solution, 28.6 grams of 70%
Waukee, Wis.) Were dissolved in 171.4 grams of 1-dodecene
(General Chemical, Parsippany, N.J.). The solution Was
(preferably about 1,000 to about 2,000 rpm, and more pref
stirred With a magnetic stir bar for more than 30 minutes and
erably about 1,200 to about 1,500 rpm). This puddling and
then ?ltered through a 0.1-p_m PTFE membrane ?lter to yield
spinning cycle can be repeated until the residual material is
dissolved aWay, usually about 1 to about 7 times (preferably
Formulation A.
about 3 to about 5 times). The substrate can then be rinsed
2. Adhesive Coating on 4-Inch Silicon Wafers
With additional hydrocarbon solvent, folloWed by a ?nal rinse
[0045]
With Water, isopropanol, 1-dodecene, acetone, methanol,
by spin coating WaferBOND® HT-10.10 bonding material
ethanol, or a mixture thereof. Preferably, the substrate is
spin-rinsed With the hydrocarbon solvent at about 300 to
about 1,000 rpm (preferably about 500 to about 800 rpm) for
about 15 to about 60 seconds (preferably about 30 to about 45
seconds), folloWed by spin-rinsing With alcohol (preferably
isopropanol) at about 300 to about 1,000 rpm (preferably
about 300 to about 900 rpm, and more preferably about 500 to
about 800 rpm) for about 15 to about 120 seconds (preferably
about 15 to about 60 seconds, and more preferably about 15 to
about 30 seconds). The substrate is then spun dry at about
1,500 to about 2,000 rpm for about 30 to about 60 seconds
(preferably 15 to about 45 seconds, and more preferably
about 15 to about 30 seconds).
[0041]
Instead of puddling the cleaning composition onto
the substrate, the surface of the substrate can be sprayed With
the cleaning solution, folloWed by rinsing and drying as
described above. In yet a further aspect, the residual bonding
material can be removed from the surface of the substrate by
immersing the substrate into cleaning composition. Prefer
ably, the substrate is immersed into the cleaning composition
for about 1 min. to about 10 min. (preferably about 1 min. to
about 5 min., and more preferably about 2 min. to about 5
min.). Immersion can be repeated as needed until the bonding
material is suf?ciently dissolved. This can be folloWed by
rinsing and drying the substrate as described above.
[0042]
Preferably, at least about 99.99% of the material is
A Wafer coated With bonding adhesive Was prepared
(BreWer Science Inc., Rolla Mo.) onto a 4-inch silicon Wafer
at 1,000 rpm for 30 seconds. The Wafer Was then baked at
1100 C. for 2 minutes and 1600 C. for 2 minutes.
3. Wafer Cleaning With Formulation A
[0046] FormulationA Was puddled onto the prepared Wafer
coated With bonding material for 60 seconds. The solution
Was then spun off at 2,000 rpm for 10 seconds. This puddling
and spinning cycle Was repeated tWice for a total of three
times. The Wafer Was then spin-rinsed With 1 -dodecene at 200
rpm for 15 seconds folloWed by isopropanol at 300 rpm for 15
seconds. The Wafer Was ?nally spun dry at 2,000 rpm for 30
seconds, and then examined under an optical microscope. It
Was observed to be clean Without particles, indicating near
complete removal of the bonding material.
Comparative Example 1
Wafer Cleaning With l-Dodecene
[0047] An adhesive-coated Wafer Was prepared by spin
coating WaferBOND® HT-10.10 bonding material (BreWer
Science Inc., Rolla Mo.) onto a 4-inch silicon Wafer at 1,000
rpm for 30 seconds. The Wafer Was then baked at 1100 C. for
2 minutes and 1600 C. for 2 minutes. The coated Wafer Was
then cleaned With ?ltered 1-dodecene using the same clean
ing process described in Example 1. The Wafer Was then
examined under an optical microscope and observed to be
dirty With many particles, indicating an incomplete removal
of the bonding material.
removed by the cleaning composition, more preferably at
least about 99.999% of the material is removed, and even
more preferably at least about 99.9999% of the material is
removed from the substrate by the cleaning composition.
When scanned With a Wafer surface inspection tool, such as a
Surfscan (available from KLA-Tencor), the cleaned substrate
Will preferably have less than about 10,000 particles per
Wafer, more preferably less than about 5,000 particles per
Wafer, and even more preferably less than about 2,000 par
ticles per Wafer, based upon a 12-inch Wafer. The cleaned
substrate(s) can then be subjected to further processing (in the
case of device Wafers) or reused (in the case of carrier Wafers).
Example 2
Wafer Cleaning With Additional Cleaning Solutions
1. Preparation of Cleaning Solutions
[0048] A. Formulation B
[0049] To prepare cleaning solution Formulation B, 200
grams of Bio-Soft S-101 (97% linear alkylbenZenesulfonic
acid from Stepan Company, North?eld, Ill.) Were dissolved in
200 grams of isopropanol. Next, 3,600 grams of mesitylene
Were added sloWly to the solution With vigorous stirring.
US 2013/0032296 A1
After the addition, the resulting solution Was stirred for more
than 30 minutes, and then ?ltered through a 0.1-p.m PTFE
membrane ?lter.
[0050] B. Formulation C
[0051] To prepare cleaning solution Formulation C, 200
grams of Bio-Soft S-101 Were dissolved in 200 grams of
1-butanol. Next, 3,600 grams of 1-dodecene Were added
sloWly to the solution With vigorous stirring. After the addi
tion, the resulting solution Was stirred for more than 30 min
utes, and then ?ltered through a 0.1-um PTFE membrane
?lter.
[0052]
[0053]
C. Formulation D
To prepare cleaning solution Formulation D, 200
grams of Bio-Soft S-101 Were dissolved in 200 grams of
1-butanol. Next, 3,600 grams of mesitylene Were added
sloWly to the solution With vigorous stirring. After the addi
tion, the resulting solution Was stirred for more than 30 min
utes, and then ?ltered through a 0.1-um PTFE membrane
?lter.
2. Adhesive Coating on 12-lnch Silicon Wafers
[0054]
Coated Wafers Were prepared by spin coating Wafer
BOND® HT-10.10 bonding material onto 12-inch silicon
Wafers at 1,500 rpm for 60 seconds. The Wafers Were then
baked at 1100 C. for 2 minutes and 1800 C. for 2 minutes.
3. Cleaning With Formulations B-D
[0055] Formulations B Was spin applied to tWo adhesive
coated Wafers, prepared above, at 900 rpm for 5 minutes. The
Wafers Were then spin-rinsed With isopropanol at 900 rpm for
1 minute, folloWed by spin drying at 2,000 rpm for 60 sec
Feb. 7,2013
2. The method of claim 1, Wherein at least about 99.99% of
said bonding material is removed by said contacting.
3. The method of claim 1, Where said ?rst substrate is a
microelectronic substrate.
4. The method of claim 3, Wherein said ?rst substrate is
selected from the group consisting of microelectromechani
cal system (MEMS) devices, display devices, ?exible sub
strates, compound semiconductors, loW k dielectric layers,
dielectric layers, ion implant layers, and substrates compris
ing silicon, aluminum, tungsten, tungsten silicide, gallium
arsenide, germanium, tantalum, tantalum nitrite, SiGe, and
mixtures of the foregoing
5. The method of claim 3, Wherein said ?rst substrate
surface comprises an array of devices selected from the group
consisting of integrated circuits, MEMS, microsensors,
poWer semiconductors, light-emitting diodes, photonic cir
cuits, interposers, embedded passive devices, and microde
vices fabricated on or from silicon and other semiconducting
materials such as silicon-germanium, gallium arsenide, and
gallium nitride.
6. The method of claim 3, said ?rst substrate surface com
prising at least one structure selected from the group consist
ing of: solder bumps; metal posts; metal pillars; and structures
formed from a material selected from the group consisting of
silicon, polysilicon, silicon dioxide, silicon (oxy)nitride,
metal, loW k dielectrics, polymer dielectrics, metal nitrides,
and metal silicides
7. The method of claim 1, Wherein said ?rst substrate
comprises a material selected from the group consisting of
silicon, sapphire, quartz, metal, glass, ceramic, and glass
onds. The tWo Wafers Were then scanned under a Surfscan
ceramic composite.
SP1 (KLA-Tencor). The particle count at above 0.5 um defect
sensitivity Was found to be 13,767 for one Wafer and 7,532 for
the other Wafer, resulting in an average particle count of
8. The method of claim 1, Wherein said contacting is
selected from the group consisting of immersing said sub
10,650.
[0056]
The above process Was repeated With Formulations
C and D. The average particle count for Formulation C Was
found to be 10,177, While the average particle count for
Formulation D Was found to be 13,548.
Comparative Example 2
strate in said cleaning composition, spraying said cleaning
composition onto said bonding material, puddling said clean
ing composition onto said bonding material, and spin-apply
ing said cleaning composition onto said bonding material.
9. The method of claim 1, Wherein said contacting is car
ried out for a time period of from about 30 seconds to about 12
hours.
10. The method of claim 1, further comprising rinsing said
Wafer Cleaning With 1-Dodecene
?rst substrate surface With a solvent selected from the group
[0057] TWo WaferBOND® HT-10.10-coated Wafers pre
pared as in Example 2 Were cleaned With ?ltered 1-dodecene
by applying the 1-dodecene to the coated Wafers at 900 rpm
for 5 minutes. The Wafers Were then spin-rinsed With isopro
methanol, ethanol, and mixtures thereof.
11. The method of claim 10, further comprising repeating
said contacting step after said rinsing.
panol at 900 rpm for 1 minute, folloWed by spin drying at
2,000 rpm for 60 seconds. Next, the Wafers Were scanned
under a Surfscan SP1. The particle count at above 0.5 pm
defect sensitivity Was found to be 85,115 for one Wafer and
86,030 for the other Wafer, With an average of 85,572.
I claim:
1. A method of removing a bonding material from a sub
strate surface, said method comprising:
providing a ?rst substrate having a surface With the bond
ing material thereon; and
contacting said bonding material With a cleaning compo
sition to thereby remove at least a portion of said bond
ing material from said substrate surface, said cleaning
composition comprising an alkylarylsulfonic acid and
an aliphatic alcohol dispersed or dissolved in a hydro
carbon solvent system.
consisting of Water, isopropanol, 1-dodecene, acetone,
12. The method of claim 1, Wherein said ?rst substrate is
bonded to a second substrate by said bonding material.
13. The method of claim 12, further comprising separating
said ?rst and second substrates.
14. The method of claim 13, Wherein said ?rst substrate
after said separating has a surface comprising residue of said
bonding material, further comprising contacting said surface
With said cleaning composition to remove said residue.
15. The method of claim 12, Wherein said second substrate
is bonded to said ?rst substrate via a layer of said bonding
material, said layer of bonding material comprising an outer
most edge, Wherein said contacting comprises contacting said
outermost edge With said cleaning composition to effect edge
removal of at least a portion of said bonding material layer.
16. The method of claim 12, Wherein said second substrate
is bonded to said ?rst substrate via a layer of said bonding
Feb. 7, 2013
US 2013/0032296 A1
material, and wherein said contacting is carried out for su?i
cient time to substantially dissolve the entire bonding mate
octylbenZenesulfonic acid, decylbenZenesulfonic acid, dode
cylbenZenesulfonic acid, tridecylbenZenesulfonic acid, tet
rial layer.
radecylbenZenesulfonic acid, hexadecylbenZenesulfonic
17. The method of claim 12, Wherein said providing com
prises:
applying said bonding material to at least one of said ?rst
and second substrates; and
contacting said substrates With one another so as to bond
said substrates together.
18. The method of claim 12, Wherein:
said ?rst substrate has a device surface comprising a plu
rality of topographical features, and said bonding mate
rial is bonded to said device surface; and
said second substrate comprises a bonding surface that is
bonded to said bonding material.
19. A microelectronic structure comprising:
a ?rst substrate having a surface, Wherein said ?rst sub
strate is a microelectronic substrate;
a quantity of bonding material adjacent said ?rst substrate
surface; and
a cleaning composition in contact With said bonding mate
rial, said cleaning composition comprising an alkylaryl
sulfonic acid and an aliphatic alcohol dispersed or dis
solved in a hydrocarbon solvent.
20. The structure of claim 19, further comprising a second
substrate bonded to said ?rst substrate by said bonding mate
rial.
21. The structure of claim 19, Wherein said bonding mate
rial is in the form of a layer adjacent said ?rst substrate
surface.
22. The structure of claim 21, further comprising a second
substrate adjacent said layer of bonding material.
23. The structure of claim 19, Wherein said bonding mate
rial is in the form of residue on said substrate surface.
24. A cleaning composition for removing temporary Wafer
bonding material comprising an alkylarylsulfonic acid and an
aliphatic alcohol dispersed or dissolved in a hydrocarbon
solvent system.
25. The composition of claim 24, Wherein said alkylaryl
sulfonic acid is selected from the group consisting of C6-Cl8
alkylarylsulfonic acids and mixtures thereof.
26. The composition of claim 24, Wherein said alkylaryl
sulfonic acid is an alkylbenZenesulfonic acid.
27. The composition of claim 26, Wherein said alkylben
Zenesulfonic acid is selected from the group consisting of
hexylbenZenesulfonic acid, heptylbenZenesulfonic acid,
acid, octadecylbenZenesulfonic acid, and mixtures thereof.
28. The composition of claim 24, Wherein said alkylaryl
sulfonic acid is in the form of reverse micelles dissolved or
dispersed in said solvent system.
29. The composition of claim 24, Wherein said composi
tion comprises from about 2 to about 15% by Weight alkylar
ylsulfonic acid, based upon the total Weight of the composi
tion taken as 100% by Weight.
30. The composition of claim 24, Wherein said aliphatic
alcohol is selected from the group consisting of Cl-C8 ali
phatic alcohols and mixtures thereof.
31. The composition of claim 24, Wherein said aliphatic
alcohol is selected from the group consisting of ethanol,
1-propanol, 2-propanol (isopropanol), 1-butanol, 2-butanol,
2-methyl-1-propanol and 2-methyl-2-propanol, allyl alcohol,
2-butyn-1-ol, 3-butyn-1-ol, 3-butyn-2-ol, 3-buten-1-ol,
3-buten-2-ol, 1-pentanol, 2-pentanol, and 1-hexanol, and
mixtures thereof.
32. The composition of claim 24, Wherein said composi
tion comprises from about 2 to about 15% by Weight of said
aliphatic alcohol, based upon the total Weight of the compo
sition taken as 100% by Weight.
33. The composition of claim 24, Wherein said hydrocar
bon solvent system includes a solvent selected from the group
consisting of C6-Cl2 hydrocarbon solvents and mixtures
thereof.
34. The composition of claim 24, Wherein said solvent
system includes a hydrocarbon solvent selected from the
group consisting of hexane, cyclohexane, heptane, octane,
1-octane, decane, 1-decene, dodecane, 1-dodecene, 1-tet
radecene, 1-hexadecene, 1-octadecene, toluene, xylene,
mesitylene, decahydronaphthalene, 1,2,3,4-tetrahydronaph
thalene, naphtha, ethyl benZene, cumene, limonene, and mix
tures thereof.
35. The composition of claim 24, Wherein said composi
tion comprises from about 70 to about 96% by Weight of said
hydrocarbon solvent system, based upon the total Weight of
the composition taken as 100% by Weight.
36. The composition of claim 24, Wherein said composi
tion consists essentially of said alkylarylsulfonic acid and
aliphatic alcohol dispersed or dissolved in said hydrocarbon
solvent system.