U.S. patent application number 13/954133 was filed with the patent office on 2015-02-05 for methods and structures for processing semiconductor devices.
This patent application is currently assigned to Micron Technology, Inc.. The applicant listed for this patent is Micron Technology, Inc.. Invention is credited to Jaspreet S. Gandhi.
Application Number | 20150035126 13/954133 |
Document ID | / |
Family ID | 52426925 |
Filed Date | 2015-02-05 |
United States Patent
Application |
20150035126 |
Kind Code |
A1 |
Gandhi; Jaspreet S. |
February 5, 2015 |
METHODS AND STRUCTURES FOR PROCESSING SEMICONDUCTOR DEVICES
Abstract
Methods of forming a semiconductor structure include exposing a
carrier substrate to a silane material to form a coating, removing
a portion of the coating at least adjacent a periphery of the
carrier substrate, adhesively bonding another substrate to the
carrier substrate, and separating the another substrate from the
carrier substrate. The silane material includes a compound having a
structure of (XO).sub.3Si(CH.sub.2).sub.nY,
(XO).sub.2Si((CH.sub.2).sub.nY).sub.2, or
(XO).sub.3Si(CH.sub.2).sub.nY(CH.sub.2).sub.nSi(XO).sub.3, wherein
XO is a hydrolyzable alkoxy group, Y is an organofunctional group,
and n is a nonnegative integer. Some methods include forming a
polymeric material comprising Si--O--Si over a first substrate,
removing a portion of the polymeric material, and adhesively
bonding another substrate to the first substrate. Structures
include a polymeric material comprising Si--O--Si disposed over a
first substrate, an adhesive material disposed over the first
substrate and at least a portion of the polymeric material, and a
second substrate disposed over the adhesive material.
Inventors: |
Gandhi; Jaspreet S.; (Boise,
ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Micron Technology, Inc. |
Boise |
ID |
US |
|
|
Assignee: |
Micron Technology, Inc.
Boise
ID
|
Family ID: |
52426925 |
Appl. No.: |
13/954133 |
Filed: |
July 30, 2013 |
Current U.S.
Class: |
257/632 ;
438/458 |
Current CPC
Class: |
H01L 24/50 20130101;
H01L 2221/6834 20130101; H01L 2221/68381 20130101; H01L 2221/68318
20130101; H01L 21/76254 20130101; H01L 21/6835 20130101; H01L 21/78
20130101; H01L 2221/68327 20130101; H01L 2924/00012 20130101; H01L
21/76251 20130101; H01L 2924/12042 20130101; H01L 2924/12042
20130101 |
Class at
Publication: |
257/632 ;
438/458 |
International
Class: |
H01L 21/762 20060101
H01L021/762; H01L 29/02 20060101 H01L029/02 |
Claims
1. A method of processing a semiconductor device, comprising:
exposing a carrier substrate to a silane material to form a coating
over a surface of the carrier substrate, the silane material
comprising a compound having a structure selected from the group
consisting of (XO).sub.3Si(CH.sub.2).sub.nY,
(XO).sub.2Si((CH.sub.2).sub.nY).sub.2, and
(XO).sub.3Si(CH.sub.2).sub.nY(CH.sub.2).sub.nSi(XO).sub.3, wherein
XO is a hydrolyzable alkoxy group, Y is an organofunctional group,
and n is a nonnegative integer; removing a portion of the coating
from the surface at least adjacent a periphery of the carrier
substrate without removing a remainder of the coating; adhesively
bonding another substrate to the carrier substrate over the
surface; and separating the another substrate from the carrier
substrate.
2. The method of claim 1, further comprising selecting XO from the
group consisting of methoxy and ethoxy groups.
3. The method of claim 1, wherein Y comprises at least one aromatic
ring.
4. The method of claim 1, further comprising at least partially
curing the coating before adhesively bonding the another substrate
to the carrier substrate.
5. The method of claim 4, wherein at least partially curing the
coating comprises curing the coating before removing the portion of
the coating adjacent the periphery of the carrier substrate.
6. The method of claim 1, wherein removing a portion of the coating
from the surface at least adjacent a periphery of the carrier
substrate comprises removing a portion of an at least partially
cured coating.
7. The method of claim 1, wherein exposing a carrier substrate to a
silane material to form a coating over a surface of the carrier
substrate comprises forming a hydrophobic coating over a surface of
the carrier substrate.
8. The method of claim 1, wherein removing a portion of the coating
from the surface at least adjacent a periphery of the carrier
substrate comprises exposing the carrier substrate to a
solvent.
9. The method of claim 1, wherein adhesively bonding another
substrate to the carrier substrate comprises applying an adhesive
over the coating and over an uncoated portion of the carrier
substrate.
10. The method of claim 1, wherein adhesively bonding another
substrate to the carrier substrate comprises applying an adhesive
over the another substrate before bonding the another substrate to
the carrier substrate.
11. The method of claim 1, wherein the silane material comprises a
material selected from the group consisting of
1,2-bis[triethoxysilyl]ethane, 1,2-bis[trimethoxysilyl]octane, and
1,2-bis[trimethoxysilyl]decane.
12. The method of claim 1, wherein exposing a carrier substrate to
a silane material to form a coating over a surface of the carrier
substrate comprises exposing the carrier substrate to a solution
comprising the silane material.
13. The method of claim 12, wherein exposing the carrier substrate
to a solution comprising the silane material comprises exposing the
carrier substrate to a solution comprising the silane material and
water.
14. The method of claim 12, wherein exposing the carrier substrate
to a solution comprising the silane material comprises exposing the
carrier substrate to a solution comprising the silane material and
an organic solvent.
15. The method of claim 14, wherein exposing the carrier substrate
to a solution comprising the silane material comprises exposing the
carrier substrate to a solution comprising about five volume
percent silane material, about five volume percent deionized water,
and about ninety volume percent methanol or ethanol.
16. A method of processing a semiconductor device, comprising:
forming a polymeric material comprising Si--O--Si over a substrate;
removing a portion of the polymeric material at least adjacent a
periphery of a surface of the substrate without removing a
remainder of the polymeric material; adhesively bonding another
substrate to the substrate over the surface; and separating the
another substrate from the substrate.
17. The method of claim 16, wherein forming a polymeric material
comprising Si--O--Si over a substrate comprises exposing the
substrate to a silane material comprising a compound selected from
the group consisting of (XO).sub.3Si(CH.sub.2).sub.nY,
(XO).sub.2Si((CH.sub.2).sub.nY).sub.2, and
(XO).sub.3Si(CH.sub.2).sub.nY(CH.sub.2).sub.nSi(XO).sub.3, wherein
XO is a hydrolyzable alkoxy group, Y is an organofunctional group,
and n is a nonnegative integer.
18. The method of claim 17, wherein forming a polymeric material
comprising Si--O--Si over a substrate further comprises curing the
silane material.
19. The method of claim 17, wherein exposing the substrate to a
silane material comprises exposing the substrate to a material
selected from the group consisting of
1,2-bis[triethoxysilyl]ethane, 1,2-bis[trimethoxysilyl]octane, and
1,2-bis[trimethoxysilyl]decane.
20. The method of claim 16, wherein forming a polymeric material
comprising Si--O--Si over a substrate comprises forming a porous
silane film.
21. The method of claim 16, further comprising forming an
interfacial layer comprising Si--O--Si and M-O--Si, wherein M is a
metal.
22. The method of claim 21, wherein adhesively bonding another
substrate to the substrate comprises adhesively bonding the another
substrate to the portion of the substrate substantially free of the
polymeric material.
23. A structure, comprising: a polymeric material comprising
Si--O--Si disposed over a first substrate surface; an adhesive
material disposed over the first substrate surface and at least a
portion of the polymeric material; and a second substrate disposed
over the adhesive material.
24. The structure of claim 23, wherein the polymeric material is
bonded to the first substrate surface by metal-oxygen-silicon
bonds.
25. The structure of claim 23, wherein the adhesive material is
bonded to the first substrate surface.
26. The structure of claim 25, wherein a bond strength between the
adhesive material and the first substrate surface is greater than a
bond strength between the adhesive material and the polymeric
material.
Description
TECHNICAL FIELD
[0001] The present disclosure, in various embodiments, relates
generally to compositions including a silane material and related
methods, such as for removably bonding wafer substrates to carrier
substrates using the compositions during processing of a
semiconductor device.
BACKGROUND
[0002] Semiconductor devices and structures thereof are typically
produced on a wafer or other bulk semiconductor substrate, which
may be referred to herein as a "device wafer." The array is then
"singulated" into individual semiconductor devices, which may also
be characterized as "dice" that are incorporated into a package for
practical mechanical and electrical interfacing with higher level
packaging, for example, for interconnection with a printed wiring
board. Device packaging may be formed on or around the die while it
is still part of the wafer. This practice, referred to in the art
as wafer-level packaging, reduces overall packaging costs and
enables reduction of device size, which may result in faster
operation and reduced power demand in comparison to than
conventionally packaged devices.
[0003] Thinning device wafer substrates is commonly used in
semiconductor device manufacture because thinning enables devices
to be stacked and helps dissipate heat. However, thinner substrates
are relatively more difficult to handle without damage to the
substrate or to the integrated circuit components thereon. To
alleviate some of the difficulties, device wafer substrates are
commonly attached to larger and more-robust carrier wafers. After
processing, the device wafer substrates may be removed from the
carrier wafers.
[0004] Common carrier materials include silicon (e.g., a blank
device wafer), soda-lime glass, borosilicate glass, sapphire, and
various metals and ceramics. The carrier wafers are commonly
substantially round and sized to match a size of the device wafer,
so that the bonded assembly can be handled in conventional
processing tools. Polymeric adhesives used for temporary wafer
bonding are conventionally applied by spin coating or spray coating
from solution or laminating as dry-film tapes. Spin- and
spray-applied adhesives are increasingly preferred because they
form coatings with higher thickness uniformity than tapes can
provide. Higher thickness uniformity translates into greater
control over cross-wafer thickness uniformity after thinning. The
polymeric adhesives also exhibit high bonding strength to the
device wafer and the carrier.
[0005] The polymeric adhesive may be spin-applied onto the device
wafer, the carrier wafer, or both. The coated wafer is baked to
remove all of the coating solvent from the polymeric adhesive. The
coated device wafer and carrier wafer are then placed in contact in
a heated mechanical press for bonding. Sufficient temperature and
pressure are applied to cause the adhesive to flow and fill into
the device wafer structural features and achieve intimate contact
with all areas of the device wafer and carrier wafer surfaces.
[0006] Removal of a device wafer from the carrier wafer after
processing is conventionally performed by chemical means (e.g.,
with a solvent), photodecomposition, thermomechanical means, or
thermodecomposition. Each of these methods has drawbacks in
production environments. For example, chemical debonding by
dissolving the polymeric adhesive is a slow process because the
solvent must diffuse over large distances through the viscous
polymer medium to effect release. That is, the solvent must diffuse
from the edge of the bonded substrates, or from a perforation in
the carrier wafer, into the local region of the adhesive. In either
case, the minimum distance from an exposed surface to a bonded area
required for solvent diffusion and penetration is typically at
least 3-5 mm and can be much greater, even with perforations to
increase solvent contact with the adhesive. Treatment times of
several hours, even at elevated temperatures (e.g., greater than
60.degree. C.), are usually utilized for debonding to occur,
meaning wafer throughput will be low.
[0007] Photodecomposition is, likewise, a slow process because the
entire bonded substrate cannot generally be exposed at one time.
Instead, the exposing light source, such as a laser having a beam
cross-section of only a few millimeters, is focused on a small area
at a time to deliver sufficient energy to decompose the adhesive
bond line. The beam is then scanned (or rastered) across the
substrate in a serial fashion to debond the entire surface, which
leads to long debonding times and low wafer throughput.
[0008] Though thermomechanical debonding can be performed typically
in a few minutes, it has other limitations that can reduce device
yield. Backside processes for temporarily bonded device wafers
often involve working temperatures higher than 200.degree. C. or
even 300.degree. C. If polymeric adhesives either decompose or
soften excessively at or near the working temperature, debonding
may occur prematurely. Adhesives are normally selected to soften
sufficiently at about 20.degree. C. to about 50.degree. C. above
the working temperature of the device wafer. The high temperature
required for debonding such adhesives imposes significant stresses
on the bonded pair as a result of thermal expansion. At the same
time, the high mechanical force utilized to move the device wafer
away from the carrier wafer by a sliding, lifting, or twisting
motion creates additional stress that can cause the device wafer to
break or produce damage within the microscopic integrated circuitry
of individual devices, which leads to device failure and yield
loss.
[0009] Thermodecomposition debonding also tends to cause wafer
breakage. Gases are produced when the polymeric adhesive is
decomposed, and these gases can become trapped between the device
wafer and the carrier wafer before the bulk of the adhesive has
been removed. The accumulation of trapped gases can cause the thin
device wafer to blister and crack or even rupture. Another problem
with thermodecomposition debonding is that polymer decomposition is
often accompanied by the formation of intractable, carbonized
residues that cannot be removed from the device wafer by
conventional cleaning procedures.
[0010] To solve problems with debonding wafers, U.S. Patent
Application Publication 2011/0308739 discloses forming a strong
bond only at the outer perimeter of the wafers. The edge bonds are
chemically, mechanically, acoustically, or thermally softened,
dissolved, or disrupted. To prevent strong bonding at the interior
of the contact surface, a polymeric fill material is coated onto
the carrier wafer before attaching an adhesive at the perimeter.
Because the polymeric fill material does not form strong bonds to
the wafers, the wafers may be separated easily by removing the
adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIGS. 1A, 2A, 3A, 4A, and 5A are top views of a
semiconductor structure according to an embodiment of the present
disclosure at various stages of processing;
[0012] FIGS. 1B, 2B, 3B, 4B, and 5B are cross-sectional views of
the semiconductor structures shown in FIGS. 1A, 2A, 3A, 4A, and 5A,
respectively; and
[0013] FIG. 6 is a cross-sectional view of a semiconductor
structure according to an embodiment of the present disclosure and
a carrier wafer after separation.
DETAILED DESCRIPTION
[0014] In some embodiments disclosed herein, methods of processing
a semiconductor device are described, as are compositions for
attaching a carrier substrate to a device wafer substrate. The
methods include exposing a carrier substrate to a silane material
to form a coating over the carrier substrate. The coating may
exhibit a lower affinity for an adhesive material than the carrier
substrate itself. A portion of the coating may be removed, such as
near an edge of the carrier substrate. An adhesive material may
then be applied to the carrier substrate to bond a wafer substrate
to the carrier substrate. The bond may be relatively weak between
the portion of the carrier substrate having the coating and the
adhesive material, such that subsequent separation of the wafer
substrate from the carrier substrate (e.g., after performing other
operations on the device wafer substrate) may be performed with
less stress on the device wafer substrate (e.g., by subjecting the
wafer substrate to weaker forces, a lower temperature, etc.).
[0015] As used herein, the terms "wafer substrate" and "device
wafer substrate" mean and include a base material or construction
upon which components, such as those of memory cells and peripheral
circuitry, as well as logic, are formed. The wafer substrate may be
a substrate wholly of a semiconductor material, a base
semiconductor material on a supporting structure, or a
semiconductor substrate having one or more materials, structures,
or regions formed thereon. The wafer substrate may be a
conventional silicon substrate or other bulk substrate including a
semiconductive material. As used herein, the term "bulk substrate"
means and includes not only silicon wafers, but also
silicon-on-insulator ("SOI") substrates, such as
silicon-on-sapphire ("SOS") substrates or silicon-on-glass ("SOG")
substrates, epitaxial layers of silicon on a base semiconductor
formdation, or other semiconductor or optoelectronic materials,
such as silicon-germanium (Si.sub.1-xGe.sub.x, wherein x is, for
example, a mole fraction between 0.2 and 0.8), germanium (Ge),
gallium arsenide (GaAs), gallium nitride (GaN), or indium phosphide
(InP), among others. Furthermore, when reference is made to a
"wafer substrate" in the following description, previous process
stages may have been utilized to form materials, regions, or
junctions, as well as connective elements such as lines, plugs, and
contacts, in the base semiconductor structure or formdation, such
components comprising, in combination, integrated circuitry.
[0016] As used herein, spatially relative terms, such as "beneath,"
"below," "lower," "bottom," "above," "upper," "top," "front,"
"rear," "left," "right," and the like, may be used for ease of
description to describe one element's or feature's relationship to
another element(s) or feature(s) as illustrated in the figures.
Unless otherwise specified, the spatially relative terms are
intended to encompass different orientations of the materials in
addition to the orientation depicted in the figures. For example,
if materials in the figures are inverted, elements described as
"below" or "beneath" or "under" or "on bottom of" other elements or
features would then be oriented "above" or "on top of" the other
elements or features. Thus, the term "below" can encompass both an
orientation of above and below, depending on the context in which
the term is used, which will be evident to one of ordinary skill in
the art. The materials may be otherwise oriented (rotated 90
degrees, inverted, flipped, etc.) and the spatially relative
descriptors used herein interpreted accordingly.
[0017] As used herein, reference to an element as being "on" or
"over" another element means and includes the element being
directly on top of, adjacent to, underneath, or in direct contact
with the other element. It also includes the element being
indirectly on top of, adjacent to, underneath, or near the other
element, with other elements present therebetween. In contrast,
when an element is referred to as being "directly on" another
element, there are no intervening elements present.
[0018] As used herein, the terms "comprises," "comprising,"
"includes," and/or "including" specify the presence of stated
features, regions, integers, stages, operations, elements,
materials, components, and/or groups, but do not preclude the
presence or addition of one or more other features, regions,
integers, stages, operations, elements, materials, components,
and/or groups thereof.
[0019] As used herein, "and/or" includes any and all combinations
of one or more of the associated listed items.
[0020] As used herein, the singular forms "a," "an," and "the" are
intended to include the plural forms as well, unless the context
clearly indicates otherwise.
[0021] Embodiments are described herein with reference to the
illustrations. The illustrations presented herein are not meant to
be actual views of any particular material, component, structure,
device, or system, but are merely idealized representations that
are employed to describe embodiments of the present disclosure.
Variations from the shapes of the illustrations as a result, for
example, of manufacturing techniques and/or tolerances, are to be
expected. Thus, embodiments described herein are not to be
construed as being limited to the particular shapes or regions as
illustrated, but include deviations in shapes that result, for
example, from manufacturing. For example, a region illustrated or
described as round may include some rough and/or linear features.
Moreover, sharp angles that are illustrated may be rounded, and
vice versa. Thus, the regions illustrated in the figures are
schematic in nature, and their shapes are not intended to
illustrate the precise shape of a region and do not limit the scope
of the present claims.
[0022] The following description provides specific details, such as
material types and processing conditions, in order to provide a
thorough description of embodiments of the disclosed compositions
and methods. However, a person of ordinary skill in the art will
understand that the embodiments of the compositions and methods may
be practiced without employing these specific details. Indeed, the
embodiments of the compositions and methods may be practiced in
conjunction with conventional semiconductor fabrication
techniques.
[0023] The fabrication processes described herein do not form a
complete process flow for processing semiconductor devices.
Preceding, intermediary, and final process stages are known to
those of ordinary skill in the art. Accordingly, only the methods
and semiconductor structures necessary to understand embodiments of
the present devices and methods are described herein.
[0024] Unless the context indicates otherwise, the materials
described herein may be formed by any conventional technique
including, but not limited to, dip coating, spin coating, spray
coating, blanket coating, chemical vapor deposition ("CVD"),
plasma-enhanced CVD, atomic layer deposition ("ALD"),
plasma-enhanced ALD, or physical vapor deposition ("PVD").
Alternatively, the materials may be grown in situ, unless the
context otherwise indicates. Depending on the specific material to
be formed, the technique for applying, depositing, growing, or
otherwise forming the material may be selected by a person of
ordinary skill in the art.
[0025] Disclosed are methods of processing semiconductor devices.
The methods include exposing a carrier substrate to a silane
material to form a coating over a surface of the carrier substrate,
removing a portion of the coating from the surface at least
adjacent a periphery of the carrier substrate without removing a
remainder of the coating, adhesively bonding another substrate to
the carrier substrate over the surface, and separating the another
substrate from the carrier substrate. The silane material includes
a compound having a structure selected from the group consisting of
(XO).sub.3Si(CH.sub.2).sub.nY,
(XO).sub.2Si((CH.sub.2).sub.nY).sub.2, and
(XO).sub.3Si(CH.sub.2).sub.nY(CH.sub.2).sub.nSi(XO).sub.3, wherein
XO is a hydrolyzable alkoxy group, Y is an organofunctional group,
and n is a nonnegative integer.
[0026] Reference will now be made to the drawings, where like
numerals refer to like components throughout. The drawings are not
necessarily to scale.
[0027] FIGS. 1A and 1B illustrate a simplified schematic of a
carrier substrate 102, and a cross-sectional view of the carrier
substrate 102 through section line 1B-1B, respectively. The carrier
substrate 102 has a surface 104 over which a wafer substrate may
subsequently be secured, as described in further detail below. A
coating 106 may be formed on the carrier substrate 102 by exposing
the carrier substrate 102 to a coat-forming composition. One or
more components of the coat-forming composition, e.g., the coating
material, may be reactive with one or more components of the
carrier substrate 102. The term "coating composition," as used
herein, refers to the composition of the resulting, formed coating
106. The coat-forming composition may not necessarily be identical
to the coating composition due to, e.g., chemical reactions between
the coat-forming composition and the carrier substrate 102 during
formation of the coating 106, or chemical reactions of the
coat-forming composition during cure.
[0028] The coat-forming composition may be formulated to form a
coating on the otherwise exposed surfaces of some or all of the
carrier substrate 102, e.g., on essentially all of a major surface
of the carrier substrate 102.
[0029] The coat-forming composition may include, for example and
without limitation, a silane material. As used herein, the terms
"silane" and "silane material" mean and include a chemical compound
including silicon and at least one other element, e.g., carbon,
hydrogen, nitrogen, sulfur, or a combination thereof. Silane
materials may be formulated as non-functional silanes or as
functional silanes.
[0030] As used herein, the term "non-functional silane" means a
silane material having an alkoxy group formulated to react with a
metal (e.g., in the carrier substrate 102) but lacking a functional
group reactive with a nonmetallic material. Non-functional silanes
may have stable functional groups connected to a silicon atom, such
as phenyl groups, tolyl groups, alkyl groups, pentafluorophenyl
groups, etc. Thus, non-functional silanes form a coating over the
carrier substrate 102 that is relatively inert to conventional
processing operations. Examples of non-functional silane materials
include, but are not limited to, silane compounds including the
formula --Si--(OC.sub.2H.sub.5).sub.x, wherein x is an integer, and
including either a methoxy or an ethoxy group bonded to the Si
atom. The methoxy or ethoxy group is hydrolyzable to form a silanol
(i.e., a --Si--OH), with an alcohol (e.g., methanol or ethanol)
formed as a by-product. Examples of such non-functional silanes
include, without limitation, the materials listed and shown in
Table 1, which table is not exhaustive.
TABLE-US-00001 TABLE 1 Examples of Non-Functional Silanes and
Chemical Structures Non-Functional Silane Chemical Structure
p-tolyltrimethoxy- silane ##STR00001## p-tolyltriethoxy- silane
##STR00002## di(p-tolyl)di- methoxysilane ##STR00003##
pentafluorophenyl- triethoxysilane ##STR00004## 1,2-bis-
[triethoxysilyl] ethane (BTSE) ##STR00005## bis- trimethoxysilyl-
ethylbenzene ##STR00006## bis- [trimethoxysilyl] octane (BTSO)
##STR00007## bis- [trimethoxysilyl] decane (BTSD) ##STR00008##
[0031] As used herein, the term "functional silane" means a silane
material formulated to react with the carrier substrate 102 and
having a functional group reactive with a nonmetallic material of
the carrier substrate 102. Functional silanes may have reactive
functional groups directly or indirectly connected to a silicon
atom, such as mercapto groups, sulfur groups, amine groups, epoxy
groups, halogen groups, alkene groups, etc. Thus, functional
silanes form a coating over the carrier substrate 102 that reacts
in some conventional processing operations. For example, without
limitation, a functional silane material may be an organofunctional
silane with one or more of the organofunctional groups or chemical
structures in Table 2, which table is not exhaustive.
TABLE-US-00002 TABLE 2 Examples of Organofunctional Groups and
Chemical Structures Organofunctional Group Example Chemical
Structure Vinyl H.sub.2C.dbd.CHSi(OCH.sub.3).sub.3 Chloropropyl
Cl(CH.sub.2).sub.3Si(OCH.sub.3).sub.3 Epoxy ##STR00009##
Methacrylate ##STR00010## Primary Amine
H.sub.2N(CH.sub.2).sub.3Si(OCH.sub.3).sub.3 Diamine
H.sub.2N(CH.sub.2).sub.2NH(CH.sub.2).sub.3Si(OCH.sub.3).sub.3
Mercapto HS(CH.sub.2).sub.3Si(OCH.sub.3).sub.3
[0032] Examples of functional and non-functional silanes include,
but are not limited to, a hybrid organic-inorganic compound with
the formula (XO).sub.3Si(CH.sub.2).sub.nY,
(XO).sub.2Si((CH.sub.2).sub.nY).sub.2, or
(XO).sub.3Si(CH.sub.2).sub.nY(CH.sub.2).sub.nSi(XO).sub.3, wherein
XO represents a hydrolyzable alkoxy group (e.g., methoxy, ethoxy),
n represents an integer, and Y represents an organofunctional
group, such as, for example and without limitation, an alkyl,
tolyl, phenyl, amino, sulfur, carboxyl, or thiol group. The
organofunctional groups Y may include various substitutions, such
as halogens, hydroxyl groups, etc. Whether such materials are
functional or non-functional depends on the characteristics of the
organofunctional group Y. For example, if the organofunctional
group Y includes fluorine-terminated groups (e.g.,
pentafluorophenyltriethoxysilane, as shown in Table 1), the
material may be non-functional because the fluorine does not tend
to react with other materials.
[0033] When a silane material, either functional or non-functional,
is hydrolyzed in water, or, alternatively, in an alcohol and water
mixture, silanol groups (i.e., Si--OH groups) may form. The silanol
groups of the hydrolyzed coat-forming composition may be reactive
with hydroxyl groups, such as those on the surface of a metal or
other element that has been exposed to oxygen and moisture. That
is, exposure of a metal or other element to oxygen may form oxides
on the surface of the metal or other element. Subsequent exposure
of the formed oxides to moisture may form M-OH bonds, wherein M
represents a metal (for example, and without limitation, Cu, Ni,
Sn, Al, Ag) or Si. Thus, metal or silicon components of the carrier
substrate 102 may include hydroxyl bonds on their surfaces.
Exposure of such hydroxyl bonds to silanol groups of a hydrolyzed
silane material may lead to reaction, e.g., a condensation
reaction, of the hydroxyl groups with the silanol groups, forming
M-O--Si bonds, wherein M represents a metal or Si--O--Si.
Accordingly, exposure of the carrier substrate 102 to a
coat-forming composition including a silane material, water, and,
optionally, an alcohol, may enable reaction between the
coat-forming composition and the surface of the carrier substrate
102 to form a coating 106 on the metallic component wherein the
coating 106 has a coating composition including M-O--Si bonds, also
referred to herein as "metal-oxygen-silicon bonds" or Si--O--Si
bonds.
[0034] Thus, some methods of processing semiconductor devices
include forming a polymeric material comprising Si--O--Si over a
surface of a substrate, removing a portion of the polymeric
material at least adjacent a periphery of the surface of the
substrate without removing a remainder of the polymeric material,
adhesively bonding another substrate to the substrate over the
surface, and separating the another substrate from the
substrate.
[0035] Both functional and non-functional silane materials may be
formulated to react with the carrier substrate 102, as described
above.
[0036] Functional silane materials may be formulated to be
additionally reactive. For example, in embodiments in which the
silane material of the coat-forming composition includes an alkoxy
(e.g., methoxy, ethoxy, etc.) group, the alkoxy groups of the
silane material are hydrolyzable to form silanols that may react
with the hydroxyl groups of the carrier substrate 102. For example,
and without limitation, the alkoxy groups of the silane material in
the coat-forming composition may be hydrolyzed to silanols as
illustrated in the following example reactions:
R'Si(OR).sub.3+H.sub.2OR'Si(OR).sub.2OH+ROH
R'Si(OR).sub.2OH+H.sub.2OR'Si(OR)(OH).sub.2+ROH
R'Si(OR)(OH).sub.2+H.sub.2OR'Si(OH).sub.3+ROH;
wherein R' and R represent hydrocarbons. The silanols may then
react with the hydroxides of the carrier substrate 102 to form
M-O--Si bonds (metal-oxygen-silicon bonds) or Si--O--Si bonds and
water as illustrated in the following reaction, wherein the dashed
line illustrates a surface of the carrier substrate 102:
##STR00011##
[0037] Examples of such alkoxy-including functional silane
materials include, but are not limited to, monosilanes such as
y-aminopropyltriethyoxysilanes (y-APS),
y-methacryloxypropyltriethoxysilanes (y-MPS), or
y-glycidoxypropyltrimethoxysilanes (y-GPS), and bis-silanes such as
bis-[trimethoxysilylpropyl]amine (available under the name
SILQUEST.RTM. A-1170 Silane from Momentive Performance Materials
Inc., of Columbus, Ohio), or
bis[3-triethoxysilylpropyl]tetrasulfide (available under the name
SILQUEST.RTM. A-1289 Silane from Momentive Performance Materials
Inc.).
[0038] The silane material of the coat-forming composition may
alternatively or additionally be formulated to include other
functional groups. For example, and without limitation, a
functional silane material including sulfur functional groups may
react with metal within the carrier substrate 102, forming M-S
bonds, also referred to herein as "metal-sulfur bonds." For
example, a sulfur group of a sulfur-based functional silane
material may react with copper within the carrier substrate 102 to
form Cu--S bonds ("copper-sulfur bonds"). Therefore, such coating
106 formed may have a coating composition including M-S bonds.
[0039] Silanol groups of a silane material, whether functional or
non-functional, may also condense with one another during formation
of the coating 106, forming Si--O--Si bonds
("silicon-oxygen-silicon bonds"). The formation of the Si--O--Si
bonds may increase the density and the viscosity of the coating
material as the coating 106 forms. Therefore, the formed coating
106 may have a coating composition including Si--O--Si bonds.
[0040] The coating 106 may be formed by exposing surfaces of one or
more materials of the carrier substrate 102 to the coat-forming
composition. The surfaces of the carrier substrate 102 may be
exposed to a coating solution that includes the coat-forming
composition, and the surfaces of the carrier substrate 102 may be
dip coated, spin coated, spray coated, or otherwise covered with
the coating solution.
[0041] Such a coating solution may include the coat-forming
composition, a solvent, and, optionally, water. The solvent used in
the coating solution may include a water-based solvent, a solvent
miscible in water, and/or an organic solvent. For example, an
organic solvent such as an alcohol (e.g., methanol, ethanol), in
which the coat-forming composition is miscible, may be used to form
the coating solution.
[0042] The solvent used in the coating solution may be selected
such that the coating solution is formulated to reduce or prevent
gelling of the coat-forming composition within the coating
solution. As used herein, the term "gelling" means and includes
thickening of the coating solution, increasing viscosity of the
coating solution, and decreasing flowability of the coating
solution prior to exposure of the carrier substrate 102 to the
coating solution. For example, use of an alcohol as the solvent may
prevent gelling of the silane material and maintain flowability of
the coating solution during application thereof on the carrier
substrate 102.
[0043] In some embodiments, the coat-forming composition may
further include water (e.g., deionized water) to facilitate
hydrolysis of the silane material to form the aforementioned
reactive silanols. Water in the coating solution may also
facilitate formation of oxide and hydroxyl groups on the carrier
substrate 102 when the carrier substrate 102 is exposed to the
coating solution. In other embodiments, the coating solution may be
formed by mixing the coat-forming composition with the solvent in
the absence of water. Water may then be introduced to the coating
solution before the coating solution is applied to the surfaces of
the carrier substrate 102. In still other embodiments, the surfaces
of the carrier substrate 102 may be first exposed to water and then
exposed to the other components (e.g., the coat-forming composition
and solvent) of the coating solution.
[0044] The coating solution may be formed by adding the
coat-forming composition including the silane material to the
solvent (e.g., alcohol), and then adding water (e.g., deionized
water). During and following addition of the components to the
coating solution, the solution may be stirred to inhibit gelling of
the silane material.
[0045] The coating solution may be formulated to exhibit a pH in
the range of from about 4 to about 9 prior to application of the
coating solution on the carrier substrate 102, which pH range may
reduce or prevent gelling of the coat-forming composition (e.g.,
silane material). A coating solution with a pH lower than about 3
or a pH greater than about 10, on the other hand, may facilitate
gelling of the silane material before exposure of the carrier
substrate 102 to the coating solution. In some embodiments, an acid
or base may be added to the coating solution to maintain the pH in
a selected range. For example, acetic acid may be added to the
coating solution.
[0046] The coating solution may include from about 1% by volume to
about 20% by volume of the coat-forming composition including the
silane material, based on the total volume of the coating solution.
For example, and without limitation, the coating solution may
include from about 5% by volume to about 10% by volume of the
coat-forming composition, from about 80% by volume to about 90% by
volume ethanol or other alcohol-based solvent, and from about 5% by
volume to about 10% by volume deionized water.
[0047] The average thickness of the coating 106 may be dependent
upon the concentration of the silane material in the coating
solution used to form the coating 106. For example, a coating
solution with a higher concentration of silane material, relative
to a solvent and, if present, other components of the coating
solution, may result in a thicker coating 106 compared to a coating
solution with a lower concentration of silane material. However,
coating solutions including high concentrations of silane material
may have a higher propensity to gel than those with lower
concentrations of silane material. Therefore, the concentration of
the silane material in the coating solution used to form the
coating 106 may be tailored to achieve a coating 106 of a selected
average thickness without excessive gelling. For example, and
without limitation, a coating solution including about 5% by volume
silane material, about 90% by volume ethanol or other alcohol-based
solvent, and about 5% by volume deionized water may be used to
produce a coating 106 with a thickness from about 250 nanometers to
about 500 nanometers. As another example, a coating solution
including about 2% by volume of silane material may be used to
produce a coating 106 with an average thickness of about 80
nanometers to about 200 nanometers.
[0048] Application of a coating solution may be self-limiting such
that one application of the coating solution covers the exposed
surfaces of the carrier substrate 102 to saturation. However, in
some embodiments, multiple applications of the coating solution may
be performed to form a thicker coating. Exposure of the carrier
substrate 102 to the coating solution may be accomplished within a
time frame of from about 30 seconds to about 1 minute, or longer if
desired.
[0049] The coating solution may optionally include another material
formulated to interact with the silane material, such as to
increase the solubility, reduce or prevent gelling, or increase the
hydrophobicity of the resulting coating 106. For example, other
materials that may be present in the coating solution include a
tetraethyl orthosilicate (TEOS) of the formula
Si--(OC.sub.2H.sub.5).sub.4, colloidal alumina, etc.
[0050] After exposure of the carrier substrate 102 to the
coat-forming composition, either by way of direct exposure to the
coat-forming composition or to a coating solution including the
coat-forming composition, the coat-forming composition may be
cured. The curing conditions may depend on the silane material used
as the coat-forming composition. By way of example, the coating
material may be cured at about 125.degree. C. for about one hour to
form the coating 106. Curing the coat-forming composition may
encourage reaction and bonding between the silane material and the
carrier substrate 102. The cure conditions may affect the
properties of the coating 106, such as the density.
[0051] The resulting coating 106 may be hydrophobic, such that
water tends to be repelled from the surface 104 of the carrier
substrate 102. For example, the coating 106 may exhibit a contact
angle with water of greater than about 60.degree., greater than
about 70.degree., or greater than about 80.degree.. In some
embodiments, the coating 106 may exhibit a contact angle with water
from about 90.degree. to about 100.degree.. In other embodiments,
the coating 106 may be superhydrophobic, exhibiting a contact angle
with water greater than about 90.degree. (e.g., about 125.degree.
or greater). As a point of reference, hydrophilic (wettable)
surfaces generally have contact angles with water of about
35.degree. or less.
[0052] A portion of the coating 106 may be removed so that an
adhesive will adhere to the carrier substrate 102. FIGS. 2A and 2B,
illustrate a simplified schematic of the carrier substrate 102
after a portion of the coating 106 has been removed, and a
cross-sectional view of the carrier substrate 102 through section
line 2B-2B, respectively. As shown in FIGS. 2A and 2B, the coating
106 may cover less than the entire surface 104 of the carrier
substrate 102. For example, the coating 106 may be removed near an
edge (e.g., a periphery) of the carrier substrate 102. The process
of removing a portion of the coating 106 may be referred to as
"edge-bead removal" if the portion of the coating 106 is removed
around a perimeter of the surface 104 of the carrier substrate 102.
The portion of the coating 106 may be removed, for example, by
exposing a portion of the carrier substrate 102 to a solvent
formulated to dissolve the coating 106. For example, the portion of
the coating 106 may be removed by exposure to isopropanol, ethanol,
methanol, acetone, etc. Alternatively, a portion of the
coat-forming composition may be removed before the coat-forming
composition is cured to form the coating 106. Portions of the
coating 106 or of the coat-forming composition may, optionally, be
selectively removed in addition to a portion near the periphery of
the surface 104 of the carrier substrate 102.
[0053] After the portion of the coating 106 has been removed from
the carrier substrate 102, an adhesive 108 may be applied over the
carrier substrate 102 and the coating 106, as shown in FIGS. 3A and
3B. FIG. 3A is a simplified schematic of the carrier substrate 102
after the adhesive 108 has been applied, and FIG. 3B is a
cross-sectional view of the carrier substrate 102 through section
line 3B-3B. The adhesive 108 may be a material capable of forming a
strong adhesive bond with the carrier substrate 102 and a weaker
bond with the coating 106. The adhesive 108 may exhibit an adhesion
strength to the carrier substrate 102 of greater than about 50
psig, such as from about 80 psig to about 250 psig, or from about
100 psig to about 150 psig. The adhesive 108 may be selected to be
thermally and chemically stable under the conditions to be used for
backside processing. For example, the adhesive 108 may be selected
to be thermally and chemically stable at temperatures of from about
150.degree. C. to about 350.degree. C., or from about 200.degree.
C. to about 300.degree. C.
[0054] In some embodiments, the adhesive 108 may include
commercially available temporary wafer-bonding compositions such as
the WAFERBOND.RTM. materials (available from Brewer Science, Inc.,
of Rolla, Mo.) and ZONEBOND.RTM. materials (available from Brewer
Science, Inc.), commercially available photoresist compositions, or
other resins and polymers. For example, the adhesive 108 may
include a high-solids, UV-curable resin system such as a reactive
epoxy or acrylic. In other embodiments, the adhesive 108 may
include a thermosetting resin system that cures or crosslinks upon
heating (e.g., two-part epoxy and silicone adhesives, cyclic olefin
polymers and copolymers with thermal catalyst initiators, and
CYCLOTENE.RTM., available from Dow Chemical Company, of Midland,
Mich.). In some embodiments, the adhesive 108 may include
ZONEBOND.RTM. 5150 (available from Brewer Science, Inc.). The
adhesive 108 may also include thermoplastic acrylic, styrenic,
vinyl halide (non-fluoro-containing), and vinyl ester polymers and
copolymers along with polyamides, polyimides, polysulfones,
polyethersulfones, and polyurethanes applied from a melt or as
solution coatings that are baked after application to dry. In some
embodiments, the adhesive 108 may include cyclic olefins,
polyolefin rubbers (e.g., polyisobutylene), or hydrocarbon-based
tackifier resins. If the adhesive 108 includes a thermosetting
material, a crosslinking agent and, optionally, a catalyst, is
added to the thermosetting material to induce crosslinking.
[0055] Also disclosed herein are structures including a polymeric
material comprising Si--O--Si disposed over a first substrate
surface, an adhesive material disposed over the first substrate
surface and at least a portion of the polymeric material, and a
second substrate disposed over the adhesive material. For example,
a wafer substrate 110 may be attached to the adhesive 108, as shown
in FIGS. 4A and 4B. FIG. 4A is a simplified schematic of the
carrier substrate 102 with the wafer substrate 110 attached, and
FIG. 4B is a cross-sectional view of the assembly through section
line 4B-4B. In some embodiments, the adhesive 108 may be applied to
the wafer substrate 110 before the wafer substrate 110 is attached
to the carrier substrate 102 (instead of or in addition to applying
the adhesive 108 to the carrier substrate 102). After attachment to
the carrier substrate 102, the wafer substrate 110 may be subjected
to backside processing by methods known in the art for processing
semiconductor substrates. For example, conventional processes may
be used to form semiconductor structures such as transistors,
capacitors, contacts, traces, lines, vias, interconnects, etc.
[0056] The backside processing may include thinning of the wafer
substrate 110 by back-grinding or other process. This processing
and thinning forms the wafer substrate 110 into what is referred to
in the art as a "thinned" wafer. The thinned wafer may be
singulated into a number of semiconductor dice, each die bearing a
number of passivated conductive elements on a major surface
thereof. Electrically conductive vias, if present, extend through
the thickness of the die singulated from the thinned wafer. A die
may be brought into proximity with another die or other substrate.
The another die or other substrate may support landing pads with
which conductive elements may be aligned.
[0057] The wafer substrate 110 may be removed from the carrier
substrate 102 after backside processing to form semiconductor
structures. FIG. 5A is a simplified schematic of the carrier
substrate 102 and the wafer substrate 110 after removal of a
portion of the adhesive 108, and FIG. 5B is a cross-sectional view
of the assembly through section line 5B-5B. As shown in FIGS. 5A
and 5B, a portion of the adhesive 108 may be removed such that no
adhesive remains attached directly to the carrier substrate 102.
For example, a portion of the adhesive 108 near the edges of the
carrier substrate 102 may be removed by chemical means (e.g., with
a solvent), photodecomposition, thermomechanical means, or
thermodecomposition. After removal of the portion of the adhesive
108, the wafer substrate 110 may be easily removed from the carrier
substrate 102 with little force or stress. That is, the bond
between the adhesive 108 and the coating 106 may be much weaker
than the bond between the adhesive 108 and the carrier substrate
102. Thus, once the bonds between the adhesive 108 and the carrier
substrate 102 are removed, the wafer substrate 110 may be removed
without harsh treatments (e.g., large stresses, high temperatures,
solvents, etc.). Such may prevent damage to the features formed on
or in the wafer substrate 110. In some embodiments, the portion of
the adhesive 108 may not be removed, but may be weakened to allow
the bonds between the adhesive 108 and the carrier substrate 102 to
be easily broken. After removal of the adhesive 108 from the
carrier substrate 102, the adhesive 108 may be removed from the
wafer substrate 110 by conventional means.
[0058] FIG. 6 shows a simplified cross-sectional view of the
carrier substrate 102 and the wafer substrate 110 after separation.
As shown in FIG. 6, the adhesive 108 may remain attached to the
wafer substrate 110, and may be substantially released from the
carrier substrate 102. The adhesive 108 may be removed from the
wafer substrate 110 as known in the art, such as by dissolving in
an organic solvent, dry etching, or grinding. Removal of the
adhesive 108 from the wafer substrate 110 and/or the carrier
substrate 102 may expose fresh surfaces for use in subsequent
processes. The coating 106 may remain on the carrier substrate 102
unless and until the coating 106 is exposed to a solvent or
otherwise treated to remove the coating 106 from the carrier
substrate 102. Thus, the carrier substrate 102 may be used in
processing subsequent wafer substrates 110 without repeating the
application, edge-bead removal, and curing of the coating 106.
[0059] While the disclosed device structures and methods are
susceptible to various modifications and alternative forms in
implementation thereof, specific embodiments have been shown by way
of example in the drawings and have been described in detail
herein. However, it should be understood that the present
disclosure is not intended to be limited to the particular forms
disclosed. Rather, the present invention encompasses all
modifications, combinations, equivalents, variations, and
alternatives falling within the scope of the following appended
claims and their legal equivalents.
* * * * *