U.S. patent application number 16/372908 was filed with the patent office on 2020-10-08 for bonded assembly containing side bonding structures and methods of manufacturing the same.
The applicant listed for this patent is SANDISK TECHNOLOGIES LLC. Invention is credited to Ryo HIRAMATSU, Koichi ITO, Katsuya KATO, Michiaki Sano, Hiroshi SASAKI, Kazuto WATANABE, Takashi YAMAHA, Hajime YAMAMOTO, Ikue YOKOMIZO.
Application Number | 20200321324 16/372908 |
Document ID | / |
Family ID | 1000005104334 |
Filed Date | 2020-10-08 |
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United States Patent
Application |
20200321324 |
Kind Code |
A1 |
Sano; Michiaki ; et
al. |
October 8, 2020 |
BONDED ASSEMBLY CONTAINING SIDE BONDING STRUCTURES AND METHODS OF
MANUFACTURING THE SAME
Abstract
A bonded assembly includes a first stack containing a first
semiconductor die bonded to a second semiconductor die along a
stacking direction, first external bonding pads formed within the
first semiconductor die, and bonding connection wires. Each of the
bonding connection wires extends over a sidewall of the first
semiconductor die and protrudes into the first semiconductor die
through the sidewall of the first semiconductor die to contact a
respective one of the first external bonding pads.
Inventors: |
Sano; Michiaki; (Ichinomiya,
JP) ; YAMAHA; Takashi; (Obu, JP) ; ITO;
Koichi; (Yokkaichi, JP) ; YOKOMIZO; Ikue;
(Nagoya, JP) ; HIRAMATSU; Ryo; (Yokkaichi, JP)
; WATANABE; Kazuto; (Nagoya, JP) ; KATO;
Katsuya; (Yokkaichi, JP) ; YAMAMOTO; Hajime;
(Nagoya, JP) ; SASAKI; Hiroshi; (Nagoya,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SANDISK TECHNOLOGIES LLC |
ADDISON |
TX |
US |
|
|
Family ID: |
1000005104334 |
Appl. No.: |
16/372908 |
Filed: |
April 2, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 23/5283 20130101;
H01L 25/18 20130101; H01L 24/09 20130101; H01L 23/5226 20130101;
H01L 24/49 20130101 |
International
Class: |
H01L 25/18 20060101
H01L025/18; H01L 23/00 20060101 H01L023/00; H01L 23/522 20060101
H01L023/522; H01L 23/528 20060101 H01L023/528 |
Claims
1. A bonded assembly, comprising: a first stack comprising a first
semiconductor die bonded to a second semiconductor die along a
stacking direction, first external bonding pads formed within the
first semiconductor die; and bonding connection wires, wherein each
of the bonding connection wires extends over a sidewall of the
first semiconductor die and protrudes into the first semiconductor
die through the sidewall of the first semiconductor die to contact
a respective one of the first external bonding pads.
2. The bonded assembly of claim 1, wherein: the first semiconductor
die comprises front-side bonding pads having respective planar
surfaces that are perpendicular to the stacking direction; the
second semiconductor die comprises backside bonding pads having
respective planar surfaces that are perpendicular to the stacking
direction; and the backside bonding pads are bonded to the
front-side bonding pads.
3. The bonded assembly of claim 2, wherein each of the bonding
connection wires comprises: an inter-die connection portion located
outside of the first semiconductor die and extends along the
stacking direction over the sidewall of the first semiconductor
die; and a first protrusion portion that protrudes into an opening
through the sidewall of the first semiconductor die and contacts
the respective one of the first external bonding pads.
4. The bonded assembly of claim 3, wherein: the first protrusion
portion comprises a first planar surface that contacts a top
surface of the respective one of the first external bonding pads
that is perpendicular to the stacking direction, and a second
planar surface that is spaced from the first planar surface by a
uniform distance; the second planar surface is within a same
two-dimensional plane as bonding surfaces of the front-side bonding
pads; and the top surface of the respective one of the first
external bonding pads that is perpendicular to the stacking
direction is offset from a plane including bonding surfaces of the
front-side bonding pads along the stacking direction by a thickness
of a segment of the first protrusion portion.
5. The bonded assembly of claim 3, further comprising second
external bonding pads formed within a second stack of two bonded
dies, wherein each of the bonding connection wires provides an
electrical connection between the respective one of the first
external bonding pads and a respective one of the second external
bonding pads by extending over the sidewall of the first stack and
over a sidewall of the stack, and protrudes into the second stack
to contact a respective one of the second external bonding
pads.
6. The bonded assembly of claim 5, wherein each of the bonding
connection wires comprises a second protrusion portion that
protrudes into an opening through the sidewall of the second stack
and contacts the respective one of the second external bonding
pads.
7. The bonded assembly of claim 6, wherein: the first protrusion
portion contacts a front-side surface of the respective one of the
first external bonding pads that faces toward the second stack, and
the second protrusion portion contacts a front-side surface of the
respective one of the second external bonding pads that faces away
from the first stack.
8. The bonded assembly of claim 7, wherein: the first protrusion
portion contacts a proximal sidewall of the respective one of the
first external bonding pads that faces toward the inter-die
connection portion; and the second protrusion portion contacts a
proximal sidewall of the respective one of the second external
bonding pads that faces toward the inter-die connection
portion.
9. The bonded assembly of claim 8, wherein: the first protrusion
portion contacts a distal sidewall of the respective one of the
first external bonding pads that faces away from the inter-die
connection portion; and the second protrusion portion contacts a
distal sidewall of the respective one of the second external
bonding pads that faces sway from the inter-die connection
portion.
10. The bonded assembly of claim 6, wherein the inter-die
connection portion continuously extends on an outer sidewall of the
first stack and on an outer sidewall of the second stack between
the first protrusion portion and the second protrusion portion.
11. The bonded assembly of claim 1, wherein the first external
bonding pads are spaced from the sidewall of the first
semiconductor die by a lateral offset distance.
12. The bonded assembly of claim 1, wherein the first external
bonding pads are physically exposed and have sidewalls that are
within a same two-dimensional plane as the sidewall of the first
semiconductor die.
13. The bonded assembly of claim 1, wherein the first external
bonding pads are offset along the stacking direction from the
second semiconductor die by a greater vertical offset distance than
backside surfaces of the front-side bonding pads are from the
second semiconductor die.
14. The bonded assembly of claim 1, further comprising a packaging
substrate attached to the first stack, wherein the bonding
connection wires are bonded to bonding pads of the packaging
substrate by wire bonding.
15. The bonded assembly of claim 1, further comprising a second
stack of bonded dies which is bonded to the first stack by the
bonding connection wires.
16. A method of forming a bonded assembly, comprising: forming a
first external bonding pad on a front side of a first semiconductor
die; forming first bonding pads on the first semiconductor die such
that bonding-side surfaces of the first bonding pads are more
distal from a substrate of the first semiconductor die than a
front-side surface of the first external bonding pad is from the
substrate; forming a first sacrificial pad cover structure over the
first external bonding pad; bonding a second semiconductor die to
the first semiconductor die such that the first bonding pads of the
first semiconductor die are bonded to second bonding pads of the
second semiconductor die; forming a first side cavity by removing
the first sacrificial pad cover structure from a sidewall of the
first semiconductor die; and forming a bonding connection wire by
injecting a bonding wire material into the first side cavity
directly on the first external bonding pad and by continuously
extracting the bonding wire material over the sidewall of the first
semiconductor die.
17. The method of claim 16, further comprising: depositing a
pad-level dielectric material layer over the first external bonding
pad, wherein the first bonding pads are formed on, or in, the
pad-level dielectric material layer; forming a recess region by
recessing a portion of the pad-level dielectric material layer
around the external bonding pad such that the front-side surface of
the first external bonding pad is physically exposed; and forming
the first sacrificial pad cover structure in the recess region on
the front-side surface of the first external bonding pad.
18. The method of claim 17, wherein removing the first sacrificial
pad cover structure from the sidewall of the first semiconductor
die comprises isotropically removing a material of the first
sacrificial pad cover structure selective to materials of the first
external bonding pad and the pad-level dielectric material
layer.
19. The method of claim 17, wherein recessing the portion of the
pad-level dielectric material layer around the external bonding pad
comprises: forming a patterned photoresist layer including an
opening having a periphery located outside of, and laterally
enclosing, a periphery of the first external bonding pad in a plan
view along a direction perpendicular to a top surface of the first
external bonding pad; and anisotropically etching portions of the
pad-level dielectric material layer within an area of the opening
in the patterned photoresist layer such that sidewalls of the first
external bonding pad are physically exposed, wherein the bonding
connection wire is formed on the sidewalls of the first external
bonding pads.
20. The method of claim 16, further comprising: forming a second
external bonding pad on the second semiconductor die; forming a
second sacrificial pad cover structure on the second external
bonding pad prior to bonding the second semiconductor die to the
first semiconductor die; forming a second side cavity by removing
the second sacrificial pad cover structure from a sidewall of the
second semiconductor die; and injecting the bonding wire material
into the second side cavity directly on the second external bonding
pad and continuously extracting the bonding wire material to the
first side cavity over a sidewall of the second semiconductor die
and over the sidewall of the first semiconductor die.
Description
FIELD
[0001] The present disclosure relates generally to the field of
semiconductor devices, and particular to a bonded assembly using
side bonding structures located on sidewalls of semiconductor dies
and methods of manufacturing the same.
BACKGROUND
[0002] Multiple semiconductor dies may be bonded together to
provide a bonded assembly. Providing reliable electrical
connections across the multiple semiconductor dies may be a
challenge because the external bonding pads of the semiconductor
dies on the top surfaces of the semiconductor dies are typically
physically exposed in order to attach the external bonding pads to
bonding wires. A configuration that staggers the semiconductor dies
results in lateral expansion of the size of the bonded assembly.
Limiting the lateral size of the bonded assembly requires reduction
of die size for the semiconductor dies that are stacked at an upper
end.
SUMMARY
[0003] According to an embodiment of the present disclosure, a
bonded assembly includes a first stack containing a first
semiconductor die bonded to a second semiconductor die along a
stacking direction, first external bonding pads formed within the
first semiconductor die, and bonding connection wires. Each of the
bonding connection wires extends over a sidewall of the first
semiconductor die and protrudes into the first semiconductor die
through the sidewall of the first semiconductor die to contact a
respective one of the first external bonding pads.
[0004] According to another embodiment of the present disclosure, a
method of forming a bonded assembly is provided, which comprises:
forming a first external bonding pad on a front side of a first
semiconductor die; forming first bonding pads on the first
semiconductor die such that bonding-side surfaces of the first
bonding pads are more distal from a substrate of the first
semiconductor die than a front-side surface of the first external
bonding pad is from the substrate; forming a first sacrificial pad
cover structure over the first external bonding pad; bonding a
second semiconductor die to the first semiconductor die such that
the first bonding pads of the first semiconductor die are bonded to
second bonding pads of the second semiconductor die; forming a
first side cavity by removing the first sacrificial pad cover
structure from a sidewall of the first semiconductor die; and
forming a bonding connection wire by injecting a bonding wire
material into the first side cavity directly on the first external
bonding pad and by continuously extracting the bonding wire
material over the sidewall of the first semiconductor die.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a schematic vertical cross-sectional view of a
first semiconductor die after formation of first bonding pads,
external bonding pads, and sacrificial pad cover structures
according to an embodiment of the present disclosure.
[0006] FIG. 2 is a schematic vertical cross-sectional view of a
second semiconductor die after formation of second bonding pads
according to an embodiment of the present disclosure.
[0007] FIG. 3 is a vertical cross-sectional view of a first
exemplary structure after bonding the second semiconductor die to
the first semiconductor die according to an embodiment of the
present disclosure.
[0008] FIG. 4 is a vertical cross-sectional view of the first
exemplary structure after thinning the substrate of the second
semiconductor die according to an embodiment of the present
disclosure.
[0009] FIG. 5 is a vertical cross-sectional view of the first
exemplary structure after optional lateral polishing according to
an embodiment of the present disclosure.
[0010] FIG. 6 is a vertical cross-sectional view of the first
exemplary structure after removal of the sacrificial pad cover
structures according to an embodiment of the present
disclosure.
[0011] FIG. 7 is a vertical cross-sectional view of the first
exemplary structure after formation of bonding connection wires in
cavities formed by removal of the sacrificial pad cover structures
according to an embodiment of the present disclosure.
[0012] FIG. 8 is a vertical cross-sectional view of a first
alternative configuration of the first exemplary structure
according to an embodiment of the present disclosure.
[0013] FIGS. 9A and 9B are vertical cross-sectional views of second
and third alternative configurations of the first exemplary
structure according to embodiments of the present disclosure.
[0014] FIG. 10A is a vertical cross-sectional view of a region of
the first semiconductor die after formation of an external bonding
pad according to an embodiment of the present disclosure.
[0015] FIG. 10B is a top-down view of the region of the first
semiconductor die of FIG. 10A.
[0016] FIG. 11A is a vertical cross-sectional view of the region of
the first semiconductor die after formation of a topmost insulating
layer and bonding pads according to an embodiment of the present
disclosure.
[0017] FIG. 11B is a top-down view of the region of the first
semiconductor die of FIG. 11A.
[0018] FIG. 12A is a vertical cross-sectional view of the region of
the first semiconductor die after formation of a patterned
photoresist layer according to an embodiment of the present
disclosure.
[0019] FIG. 12B is a top-down view of the region of the first
semiconductor die of FIG. 12A.
[0020] FIG. 13A is a vertical cross-sectional view of the region of
the first semiconductor die after formation of a recess region
according to an embodiment of the present disclosure.
[0021] FIG. 13B is a top-down view of the region of the first
semiconductor die of FIG. 13A.
[0022] FIG. 14A is a vertical cross-sectional view of the region of
the first semiconductor die after deposition of a sacrificial fill
material layer according to an embodiment of the present
disclosure.
[0023] FIG. 14B is a top-down view of the region of the first
semiconductor die of FIG. 14A.
[0024] FIG. 15A is a vertical cross-sectional view of the region of
the first semiconductor die after formation of a sacrificial pad
cover structure according to an embodiment of the present
disclosure.
[0025] FIG. 15B is a top-down view of the region of the first
semiconductor die of FIG. 15A.
[0026] FIG. 16A is a vertical cross-sectional view of a region of
the first exemplary structure of FIG. 3.
[0027] FIG. 16B is a horizontal cross-sectional view along the
horizontal plane B-B' of the region of FIG. 16A.
[0028] FIG. 17A is a vertical cross-sectional view of a region of
the first exemplary structure of FIG. 5.
[0029] FIG. 17B is a horizontal cross-sectional view along the
horizontal plane B-B' of the region of FIG. 17A.
[0030] FIG. 18A is a vertical cross-sectional view of a region of
the first exemplary structure of FIG. 6.
[0031] FIG. 18B is a horizontal cross-sectional view along the
horizontal plane B-B' of the region of FIG. 18A.
[0032] FIG. 19A is a vertical cross-sectional view of a region of
one of the first exemplary structures of FIGS. 7-9.
[0033] FIG. 19B is a horizontal cross-sectional view along the
horizontal plane B-B' of the region of FIG. 19A.
[0034] FIG. 20 is a cross-sectional view of a second exemplary
structure including a plurality of bonded semiconductor dies at the
processing steps of FIGS. 9A, 9B, 18A, and 18B according to an
embodiment of the present disclosure.
[0035] FIGS. 21-24 are sequential cross-sectional views of the
second exemplary structure including a plurality of bonded
semiconductor dies at the processing steps of FIGS. 7-9, 19A, and
19B according to an embodiment of the present disclosure.
[0036] FIG. 25 is a cross-sectional view of an alternative
embodiment of the second exemplary structure including a plurality
of bonded semiconductor dies after the processing steps of FIGS.
7-9, 19A, and 19B according to an embodiment of the present
disclosure.
[0037] FIG. 26A is a top-down view of a first exemplary layout of
bonding connection wires according to an embodiment of the present
disclosure.
[0038] FIG. 26B is a side view of the structure of FIG. 26A.
[0039] FIG. 27A is a top-down view of a second exemplary layout of
bonding connection wires according to an embodiment of the present
disclosure.
[0040] FIG. 27B is a side view of the structure of FIG. 27A.
DETAILED DESCRIPTION
[0041] As discussed above, the embodiments of the present
disclosure are directed to a bonded assembly using side bonding
structures located on sidewalls of semiconductor dies and methods
of manufacturing the same, the various embodiments of which are
described below. The embodiments of the disclosure may be used to
form a bonded assembly including at least one memory die and at
least one logic die and optionally including a packaging substrate.
The embodiments disclosed herein provide a structure and a method
that provides electrical connections across multiple semiconductor
dies without requiring lateral size expansion of the bonded
assembly or gradual decrease in die size in upper semiconductor
dies. The drawings are not drawn to scale. Multiple instances of an
element may be duplicated where a single instance of the element is
illustrated, unless absence of duplication of elements is expressly
described or clearly indicated otherwise. Ordinals such as "first,"
"second," and "third" are used merely to identify similar elements,
and different ordinals may be used across the specification and the
claims of the instant disclosure. The same reference numerals refer
to the same element or similar element. Unless otherwise indicated,
elements having the same reference numerals are presumed to have
the same composition and the same function. Unless otherwise
indicated, a "contact" between elements refers to a direct contact
between elements that provides an edge or a surface shared by the
elements. As used herein, a first element located "on" a second
element may be located on the exterior side of a surface of the
second element or on the interior side of the second element. As
used herein, a first element is located "directly on" a second
element if there exist a physical contact between a surface of the
first element and a surface of the second element. As used herein,
a first element is "electrically connected to" a second element if
there exists a conductive path consisting of at least one
conductive material between the first element and the second
element. As used herein, a "prototype" structure or an "in-process"
structure refers to a transient structure that is subsequently
modified in the shape or composition of at least one component
therein.
[0042] As used herein, a "layer" refers to a material portion
including a region having a thickness. A layer may extend over the
entirety of an underlying or overlying structure, or may have an
extent less than the extent of an underlying or overlying
structure. Further, a layer may be a region of a homogeneous or
inhomogeneous continuous structure that has a thickness less than
the thickness of the continuous structure. For example, a layer may
be located between any pair of horizontal planes between, or at, a
top surface and a bottom surface of the continuous structure. A
layer may extend horizontally, vertically, and/or along a tapered
surface. A substrate may be a layer, may include one or more layers
therein, or may have one or more layer thereupon, thereabove,
and/or therebelow.
[0043] As used herein, a first surface and a second surface are
"vertically coincident" with each other if the second surface
overlies or underlies the first surface and there exists a vertical
plane or a substantially vertical plane that includes the first
surface and the second surface. A substantially vertical plane is a
plane that extends straight along a direction that deviates from a
vertical direction by an angle less than 5 degrees. A vertical
plane or a substantially vertical plane is straight along a
vertical direction or a substantially vertical direction, and may,
or may not, include a curvature along a direction that is
perpendicular to the vertical direction or the substantially
vertical direction.
[0044] A monolithic three-dimensional memory array is a memory
array in which multiple memory levels are formed above a single
substrate, such as a semiconductor wafer, with no intervening
substrates. The term "monolithic" means that layers of each level
of the array are directly deposited on the layers of each
underlying level of the array. In contrast, two dimensional arrays
may be formed separately and then packaged together to form a
non-monolithic memory device. For example, non-monolithic stacked
memories have been constructed by forming memory levels on separate
substrates and vertically stacking the memory levels, as described
in U.S. Pat. No. 5,915,167 titled "Three-dimensional Structure
Memory." The substrates may be thinned or removed from the memory
levels before bonding, but as the memory levels are initially
formed over separate substrates, such memories are not true
monolithic three-dimensional memory arrays. The various
three-dimensional memory devices of the present disclosure include
a monolithic three-dimensional NAND string memory device, and may
be fabricated using the various embodiments described herein.
[0045] Generally, a semiconductor package (or a "package") refers
to a unit semiconductor device that may be attached to a circuit
board through a set of pins or solder balls. A semiconductor
package may include a semiconductor chip (or a "chip") or a
plurality of semiconductor chips that are bonded throughout, for
example, by flip-chip bonding or another chip-to-chip bonding. A
package or a chip may include a single semiconductor die (or a
"die") or a plurality of semiconductor dies. A die is the smallest
unit that may independently execute external commands or report
status. Typically, a package or a chip with multiple dies is
capable of simultaneously executing as many external commands as
the total number of planes therein. Each die includes one or more
planes. Identical concurrent operations may be executed in each
plane within a same die, although there may be some restrictions.
In case a die is a memory die, i.e., a die including memory
elements, concurrent read operations, concurrent write operations,
or concurrent erase operations may be performed in each plane
within a same memory die. In a memory die, each plane contains a
number of memory blocks (or "blocks"), which are the smallest unit
that may be erased by in a single erase operation. Each memory
block contains a number of pages, which are the smallest units that
may be selected for programming. A page is also the smallest unit
that may be selected to a read operation.
[0046] Referring to FIG. 1, a first semiconductor die 700 according
to an embodiment of the present disclosure is illustrated. The
first semiconductor die 700 may be a logic die or a memory die. The
first semiconductor die 700 may include first semiconductor devices
710 formed on a first semiconductor substrate 106. The first
semiconductor devices 710 may include field effect transistors
and/or memory devices such as a three-dimensional memory array.
First dielectric material layers 760 may be formed over the first
semiconductor devices 710, and first metal interconnect structures
780 may be formed within the first dielectric material layers 760.
First bonding pads 788 may be formed in, or on, an uppermost layer
of the first dielectric material layers 760. The first bonding pads
788 may be die-to-die bonding pads that are configured to be bonded
to die-to-die bonding pads of another semiconductor die, such as a
second semiconductor die 900 illustrated in FIG. 2. First external
bonding pads 80 formed within a respective first sacrificial pad
cover structure 96 may be formed on the first semiconductor die
700.
[0047] The side of the first semiconductor die 700 including the
first dielectric material layers 760 and the first bonding pads 788
(which are first die-to-die bonding pads) is herein referred to as
a front side of the first semiconductor die 700. The side of the
first semiconductor die 700 including the first semiconductor
substrate 106 is herein referred to as a backside of the first
semiconductor die 700. Each of the first bonding pads 788 may be a
metal bonding pad that may form metal-to-metal bonding. For
example, the first bonding pads 788 may comprise copper at a
material composition that provides copper-to-copper bonding.
[0048] Each of the first external bonding pads 80 may be formed
within a respective first sacrificial pad cover structure 96. The
first bonding pads 788 may be formed on the first semiconductor die
700 such that bonding-side surfaces of the first bonding pads 788
are more distal from the first semiconductor substrate 106 (i.e.,
the substrate of the first semiconductor die 700) than a surface of
the first external bonding pads 80 are from the first semiconductor
substrate 106. In other words, the first external bonding pads 80
are vertically recessed relative to the horizontal plane including
the top surfaces of the first bonding pads 788. Each first
sacrificial pad cover structure 96 may be formed over a respective
first external bonding pad 80, and may have a top surface located
within the horizontal plane including the top surfaces of the first
bonding pads 788. The methods of forming external bonding pads such
as the first bonding pads 788 of the first semiconductor die 700
are subsequently described in detail.
[0049] Referring to FIG. 2, a second semiconductor die 900
according to an embodiment of the present disclosure is
illustrated. The second semiconductor die 900 may be a logic die or
a memory die. The second semiconductor die 900 may include second
semiconductor devices formed on a second semiconductor substrate
906. The second semiconductor devices may include field effect
transistors and/or memory devices such as a three-dimensional
memory array. In an illustrative example, the second semiconductor
devices may include an alternating stack of insulating layers 32
and electrically conductive layers 46 that function as word lines,
and memory stack structures 58 vertically extending through the
alternating stack (32, 46). In this case, each of the memory stack
structures 58 may include a respective vertical semiconductor
channel and a respective memory film. Each memory film may include
a layer stack of a charge storage layer and a tunneling dielectric
layer. Each vertical semiconductor channel may be connected to a
source region at one end such as a bottom end, and may be connected
to a drain region at another end such as a top end. A retro-stepped
dielectric material portion 65 may be formed on stepped surfaces of
the alternating stack (32, 46). Second dielectric material layers
960 may be formed over the second semiconductor devices, and second
metal interconnect structures 980 may be formed in the second
dielectric material layers 960. In case the second semiconductor
die 900 includes a three-dimensional array of memory elements, the
second metal interconnect structures 980 may include drain contact
via structures 88 that contact the drain regions, and bit lines 108
that laterally extend along a horizontal direction that is
perpendicular to a lengthwise direction of the word lines as
embodied as the electrically conductive layers 46.
[0050] Second bonding pads 988 may be formed in, or on, an
uppermost layer of the second dielectric material layers 960. The
second bonding pads 988 may be die-to-die bonding pads that are
configured to be bonded to die-to-die bonding pads of another
semiconductor die, such as the first semiconductor die 700
illustrated in FIG. 1. In one embodiment, the second bonding pads
988 may have an image pattern that mirrors the pattern of the first
bonding pads 788. In one embodiment, the second semiconductor die
900 may be a memory die including a three-dimensional array of
memory elements, and the first semiconductor die 700 may include a
peripheral circuitry that controls operation of the
three-dimensional array of memory elements. In one embodiment, the
first semiconductor die 700 and the second semiconductor die 900
may be memory dies.
[0051] Referring to FIG. 3, the second bonding pads 988 may be
bonded to the first bonding pads 788 to form a bonded assembly
comprising a stack 800 of two bonded dies including the first
semiconductor die 700 and the second semiconductor die 900. One
side of the bonded assembly, such as the side including the second
semiconductor substrate 906, is herein referred to as a front side,
and another side of the bonded assembly, such as the side including
the first semiconductor substrate 106, is herein referred to as a
backside. As such, the first bonding pads 788 of the first
semiconductor die 700 is herein referred to as front-side bonding
pads 788 of the first semiconductor die 700 (which is located on
the front side of the first semiconductor die 700 in the bonded
state), and the second bonding pads 988 of the second semiconductor
die 900 is herein referred to as backside bonding pads 988 of the
second semiconductor die 900 (which is located on the backside of
the second semiconductor die 900 in the bonded state). Thus, the
front-side bonding pads 788 of the first semiconductor die 700 are
bonded to the backside bonding pads 988 of the second semiconductor
die 900.
[0052] Referring to FIG. 4, the second semiconductor substrate 906,
i.e., the substrate of the second semiconductor die 900, may be
thinned, for example, by grinding, polishing, an isotropic etch
process, and/or an anisotropic etch process. In one embodiment, the
thickness of the second semiconductor substrate 906 may be in a
range from 1 micron to 60 microns so that through-substrate contact
via structures may be subsequently formed through the second
semiconductor substrate 906.
[0053] Referring to FIG. 5, the bonded assembly comprising the
stack 800 may be optionally thinned on one or more sides of the
bonded assembly that includes the first sacrificial pad cover
structure 96. If the first sacrificial pad cover structure 96 are
provided only on one side of the bonded assembly, the side of the
bonded assembly including the first sacrificial pad cover structure
96 may be thinned. If the first sacrificial pad cover structure 96
are provided on multiple sides, each side including the first
sacrificial pad cover structure 96 may, or may not, be thinned.
Portions of the first semiconductor die 700 and the second
semiconductor die 900 adjacent to each thinned side may be removed
during the thinning process. The thinning process may use
polishing, grinding, an isotropic etch process, and/or an
anisotropic etch process. In embodiments where the first
sacrificial pad cover structure 96 is physically exposed to any
sidewall of the bonded assembly, such a side may, or may not, be
thinned. If any of the first sacrificial pad cover structure 96 is
not physically exposed in the bonded assembly of FIG. 4, such a
side may be thinned until each buried first sacrificial pad cover
structure 96 may be physically exposed. In one embodiment,
sidewalls of the first sacrificial pad cover structure 96 may be
physically exposed and sidewalls of the first external bonding pads
80 may not be physically exposed after thinning, or without
thinning in case the thinning process is omitted. In another
embodiment, sidewalls of the first sacrificial pad cover structure
96 may be physically exposed and sidewalls of the first external
bonding pads 80 may be physically exposed after thinning, or
without thinning in case the thinning process is omitted.
[0054] Referring to FIG. 6, the first sacrificial pad cover
structures 96 may be removed selective to the materials of the
first dielectric material layers 760, the second dielectric
material layers 960, and the first external bonding pads 80. First
side cavities 97 may be formed in volumes from which the first
sacrificial pad cover structures 96 are removed. In one embodiment,
removal of the first sacrificial pad cover structures 96 from the
sidewall(s) of the first semiconductor die 700 may be effected by
isotropically removing the material of the first sacrificial pad
cover structures 96 selective to materials of the first external
bonding pads 80 and the dielectric material layers (760, 960) of
the first semiconductor die 700 and the second semiconductor die
900 (which include a pad-level dielectric material layer that has
formed therein the front-side bonding pads 788).
[0055] Referring to FIG. 7, a metallic bonding material may be
applied into each of the first side cavities 97, and may be
subsequently extracted to form bonding connection wires 98. The
bonding connection wires 98 may be anchored to the first external
bonding pad 80 by filling the distal sidewall of the first external
bonding pad 80. The bonding connection wires 98 may continuously
extend to another semiconductor die (which may, or may not, be
another bonded assembly comprising a stack 800) and/or to another
substrate, such as a packaging substrate (not shown), and may be
bonded to a respective external bonding pad located on the
semiconductor die or the substrate. FIG. 7 illustrates an
embodiment in which a sidewall of a first external bonding pad 80
is vertically coincident with sidewalls of the first semiconductor
die 700 and the second semiconductor die 900. As used herein, a
first surface and a second surface are vertically coincident with
each other if there exists a vertical plane including the first
surface and the second surface and if the second surface overlies
or underlies the first surface.
[0056] FIG. 8 illustrates a first alternative configuration of the
bonded assembly comprising a stack 800 of the first exemplary
structure in which an outer sidewall of a first external bonding
pad 80 is laterally recessed relative to most proximal sidewalls of
the first semiconductor die 700 and the second semiconductor die
900, and a bonding connection wire 98 partially fills the first
side cavity 97 formed by removal of a first sacrificial pad cover
structure 96. This configuration is advantageous because it may
reduce the stress of the bonding wire which will be described
below.
[0057] FIG. 9A illustrates a second alternative configuration of
the bonded assembly comprising a stack 800 of the first exemplary
structure in which an outer sidewall of a first external bonding
pad 80 is laterally recessed relative to most proximal sidewalls of
the first semiconductor die 700 and the second semiconductor die
900, and a bonding connection wire 98 completely fills the first
side cavity 97 formed by removal of a first sacrificial pad cover
structure 96. FIG. 9B illustrates a third alternative configuration
of the bonded assembly comprising a stack 800 of the first
exemplary structure in which the bonding connection wire 98 does
not extend over the inner sidewall of first external bonding pad
80.
[0058] Generally, each bonding connection wire 98 may be formed by
injecting a bonding wire material into a respective first side
cavity 97 directly on a respective first external bonding pad 80,
and by continuously extracting the bonding wire material over the
sidewall of the bonded assembly (e.g., over the sidewall of the
stack 800), such as the sidewall of the first semiconductor die 700
and/or over the sidewall of the second semiconductor die 900.
[0059] FIGS. 10A-19B illustrate the processing steps of FIGS. 1-9
in more detail through a series of magnified views.
[0060] Referring to FIGS. 10A and 10B, a region of the first
semiconductor die 700 is illustrated in a vertical cross-sectional
view and in a top-down view, respectively, after formation of a
first external bonding pad 80. Interconnect-level dielectric
material layers 761 may be formed over the first semiconductor
devices 710 on the first semiconductor substrate 106 illustrated in
FIG. 1. The interconnect-level dielectric material layers 761
include a subset of layers within the first dielectric material
layers 760 that excludes a pad-level dielectric material layer to
be subsequently formed. The first metal interconnect structures 780
may be formed within the interconnect-level dielectric material
layers 761. The first external bonding pads 80 may be formed
concurrently with formation of a subset of the first metal
interconnect structures 780, or may be formed in a separate
processing step. In one embodiment, the first external bonding pads
80 may include at least one conductive material that is different
from the materials of the first metal interconnect structures 780.
In one embodiment, the first external bonding pads 80 may include
at least one metallic material optimized for bonding with a bonding
connection wire. For example, the first external bonding pads 80
may include a metal pad 80A (such as a copper pad or an aluminum
pad) and an underbump metallurgy (UBM) stack 80B. An exemplary UBM
stack 80B includes, from bottom to top, a bulk metal layer (such as
a nickel layer) and a passivation metal layer such as a gold layer
and/or a palladium layer having a thickness in a range from 100 nm
to 3,000 nm.
[0061] Referring to FIGS. 11A and 11B, a pad-level dielectric
material layer 762 may be formed over the interconnect-level
dielectric material layers 761. The combination of the
interconnect-level dielectric material layers 761 and the pad-level
dielectric material layer 762 constitutes the first dielectric
material layers 760. The various component layers of the first
dielectric material layers 760 include a respective dielectric
material such as silicon oxide, silicon nitride, or organosilicate
glass. The thickness of the pad-level dielectric material layer 762
may be in a range from 400 nm to 8,000 nm, although lesser and
greater thicknesses may also be used. The first bonding pads 788
may be formed on, or in, the pad-level dielectric material layer
762.
[0062] Referring to FIGS. 12A and 12B, a photoresist layer 763 may
be applied over the pad-level dielectric material layer 762, and
may be lithographically patterned to form openings over areas of
the first external bonding pads 80. In one embodiment, the shapes
of the openings in the photoresist layer 763 may be selected such
that the entire area of each first external bonding pad 80 is
located entirely inside a periphery of an overlying opening in the
photoresist layer 763. Each opening in the patterned photoresist
layer 763 may have a periphery located outside of, and laterally
enclosing, a periphery of an underlying first external bonding pad
80 in a plan view along a direction perpendicular to the top
surfaces of the first external bonding pads 80, i.e., in the plan
view along the vertical direction. A finite lateral offset may be
provided between the periphery of each first external bonding pad
80 and the periphery of the overlying opening in the photoresist
layer 763. All first bonding pads 788 may be covered by the
photoresist layer 763.
[0063] Referring to FIGS. 13A and 13B, an anisotropic etch process
may be performed to transfer the pattern of the openings in the
photoresist layer 763 through the entire thickness of the pad-level
dielectric material layer 762. Portions of the pad-level dielectric
material layer 762 may be vertically recessed around each first
external bonding pad 80 such that the front-side surface of each
first external bonding pad 80 is physically exposed. An entire top
surface of each first external bonding pad 80 may be physically
exposed by the anisotropic etch process.
[0064] Optionally, the anisotropic etch process may be extended
after the top surfaces of the first external bonding pads 80 are
physically exposed. The chemistry of the anisotropic etch process
may be selected such that the anisotropic etch process etches the
material(s) of the interconnect-level dielectric material layers
761 selective to the material of the first external bonding pads
80. A top surface of the interconnect-level dielectric material
layers 761 may be vertically recessed relative to the top surfaces
of the first external bonding pads 80. In this case, the pad-level
dielectric material layer 762 is anisotropically etched within the
areas of the openings in the patterned photoresist layer 763 such
that sidewalls of the first external bonding pads 80 are physically
exposed. A recess region 89 may be formed over each first external
bonding pad 80. Each recess region 89 may have an area of the
overlying opening in the photoresist layer 763. The photoresist
layer 763 may be subsequently removed, for example, by ashing or by
an organic solvent to avoid oxidation.
[0065] Referring to FIGS. 14A and 14B, a sacrificial fill material
layer 96L may be deposited in the recess regions 89 and over the
first dielectric material layers 760. The sacrificial fill material
layer 96L includes a material that may be subsequently removed
selective to materials of the first dielectric material layers 760
and the first external bonding pads 80. In one embodiment, the
sacrificial fill material layer 96L may include a polymer material
layer that may be subsequently dissolved selective to the materials
of the first dielectric material layers 760 and the first external
bonding pads 80. For example, the sacrificial fill material layer
96L may include polyimide. Alternatively, the sacrificial fill
material layer 96L may include a material that may be removed
selective to the materials of the first dielectric material layers
760 and the first external bonding pads 80 by ashing. For example,
the sacrificial fill material layer 96L may include amorphous
carbon or a carbon-based material. The thickness of the sacrificial
fill material layer 96L may be greater than the maximum depth of
the recess regions 89 so that the recess regions 89 are completely
filled.
[0066] Referring to FIGS. 15A and 15B, excess portions of the
sacrificial fill material overlying the horizontal plane including
the top surfaces of the first dielectric material layers 760 and
the first bonding pads 788 may be removed by a planarization
process such as chemical mechanical planarization. Each remaining
portion of the sacrificial fill material that fills the recess
regions 89 constitutes a sacrificial pad cover structure 96. Each
first external bonding pad 80 may be covered by a respective
sacrificial pad cover structure 96 having a top surface that is
coplanar with the top surface of the first dielectric material
layers 760 and physically exposed front-side surfaces of the first
bonding pads 788. The first semiconductor die 700 of FIG. 1 may be
provided upon completion of the processing steps of FIGS. 15A and
15B.
[0067] Referring to FIGS. 16A and 16B, the processing steps of
FIGS. 3 and 4 may be performed to form a bonded assembly of the
first semiconductor die 700 and the second semiconductor die 900,
and optionally to thin the second semiconductor substrate 906
and/or to thin the first semiconductor substrate 106.
[0068] Referring to FIGS. 17A and 17B, sidewalls of the bonded
assembly may be optionally thinned on any, or each, side that
includes first external bonding pads 80. A sidewall of each of the
sacrificial pad cover structures 96 may be physically exposed. The
first external pad structures 80, and thus, the sacrificial pad
cover structures 96, may be provided on one side, two sides,
three-sides, or four sides of the first semiconductor die 700. Each
of the first external bonding pads 80 may, or may not, have a
physically exposed sidewall depending on the extent of thinning of
the sidewall(s) of the bonded assembly of the first semiconductor
die 700 and the second semiconductor die 900. In this step, the
dicing saw (e.g., laser saw) does not cut into the metal of the
first external bonding pads 80. The decreases the amount of metal
dust generated during dicing, which decreases the chance of a short
circuit caused by the metal dust. Thus, in one embodiment, the
first external bonding pads 80 may be laterally spaced apart by
distance from the dicing line to reduce or avoid generation of the
metal dust during dicing.
[0069] Referring to FIGS. 18A and 18B, the sacrificial pad cover
structures 96 may be removed selective to the materials of the
first dielectric material layers 760, the second dielectric
material layers 960, and the first external bonding pads 80. For
example, if the sacrificial pad cover structures 96 include
polyimide or another polymer material that may be dissolved in an
organic solvent, removal of the sacrificial pad cover structures 96
may be performed by dissolving the sacrificial pad cover structures
96 in such an organic solvent. Alternatively, the sacrificial pad
cover structures 96 may be removed by ashing.
[0070] Referring to FIGS. 19A and 19B, a metallic bonding material
may be applied into each of the first side cavities 97, and may be
subsequently extracted to form bonding connection wires 98. The
bonding connection wires 98 may continuously extend to another
semiconductor die (which may, or may not, be the second
semiconductor die 900) and/or to another substrate such as a
packaging substrate (not shown), and may be bonded to a respective
external bonding pad located on the semiconductor die or the
substrate.
[0071] The bonding connection wire 98 may include a protrusion
portion 98P that may protrude into an opening through the sidewall
of the first semiconductor die 700 and contacts a first external
bonding pad 80, and an inter-die connection portion 981 that is
connected to the protrusion portion 98P. The protrusion portion 98P
contacts a front-side surface of the first external bonding pad 80
that faces toward the second semiconductor die 900. The protrusion
portion 98P contacts a proximal sidewall 8P of the first external
bonding pad 80 that faces toward the inter-die connection portion
981, and contacts a distal sidewall 8D of the first external
bonding pad 80 that faces away from the inter-die connection
portion 981. As shown in the cross section of FIG. 19, the bonding
connection wire 98 may surround the first external bonding pad 80
in order to anchor the bonding connection wire 98 in a secure
manner both over and around the first external bonding pad 80. The
secure anchoring of the bonding connection wire 98 may provide an
anti-peeling feature to the bonding wire 98.
[0072] Referring to FIG. 20, a second exemplary structure including
an assembly 1100 containing plurality of the stacks 800 is
illustrated at the processing steps of FIGS. 9A, 9B, 18A, and 18B.
The assembly 1100 of the second exemplary structure of FIG. 20 may
be formed by stacking multiple stacks 800 described above and
optionally a packaging substrate 1000. The stacks 800 may be
connected to each other by glue and/or a mechanical fastener to
form the assembly 1100. Each of the multiple stacks 800 includes a
respective set of external bonding pads 80 and a respective set of
side cavities in the same manner as the first semiconductor die 700
illustrated in FIGS. 6, 18A, and 18B. The multiple stacks 800 may
comprise memory dies, logic dies (such as a support die for a
memory die) or a combination of memory and logic dies. For example,
each stack 800 may comprise a memory die 900 bonded to a logic
support die 700 as described in the prior embodiments. For example,
at least two stacks, such as three to twenty stacks, for example
seven stacks 800 (e.g., 800A, 800B, 800C, 800D, 800E, 800F and
800G) may be stacked with a respective major surface of one stack
(e.g., 800A) contacting a major surface on an adjacent stack (e.g.,
800B) and with the outer sidewalls exposed.
[0073] The processing steps of FIGS. 9A, 9B, 18A, and 18B may be
performed to form side cavities 97 within each of the stacks 800,
such that the side cavities 97 are exposed before or after stacking
the stacks 800 together. A packaging substrate 1000 may be attached
to the first stack 800A. The packaging substrate 1000 may be any
packaging substrate known in the art. If used, the packaging
substrate 1000 may be a laminate packaging substrate or a ceramic
packaging substrate. Each stack 800 within the assembly includes a
respective set of external bonding pads 80 that are physically
exposed to a respective set of side cavities 97.
[0074] Referring to FIG. 21, a wire extraction apparatus 300 may be
used to inject a bonding wire material into a side cavity 97
located on a first external bonding pad 80 to which a bonding
connection wire 98 is to be connected. In one embodiment, the
bonding wire material may extrude through a tip 398 of the wire
extraction apparatus 300 into the side cavity 97.
[0075] Referring to FIG. 22, the bonding wire material is
continuously extracted over a sidewall of the stack 800 (e.g., the
support die 700 of stack 800G) that forms an initial portion of the
bonding connection wire toward a next side cavity 97 that borders a
next external bonding pad 80 to be subsequently bonded.
[0076] Referring to FIG. 23, the bonding wire material is
continuously extracted to form a next portion that fills a second
side cavity 97 and contacts a second external bonding pad 80 in the
next semiconductor die 700 of the next stack 800F.
[0077] Referring to FIG. 24, the processing steps of FIG. 23 may be
repeated until the bonding connection wire 98 continuously extends
across all of the stacks 800 and optionally to the packaging
substrate 1000, and provides electrical connection across a set of
external bonding pads 80 that are distributed across multiple
stacks 800 and optionally in the packaging substrate 1000. In one
embodiment, the bonding connection wire 98 may be formed with loops
so that the bonding connection wire 98 does not contact sidewalls
of the stacks 800 outside regions in which the bonding connection
wire 98 protrudes into side cavities of the stacks 800.
[0078] Referring to FIG. 25, an alternative embodiment of the
second exemplary structure is illustrated, in which a bonding
connection wire 98 is formed directly on insulating sidewalls of
the stacks 800.
[0079] Referring to FIGS. 26A and 26B, multiple bonding connection
wires 98 may be used to provide electrical connections across
multiple stacks 800. At least one, and/or each, of the bonding
connection wires 98 may provide electrical connection across a
respective set of external bonding pads 80 located in multiple
stacks 800.
[0080] Referring to FIGS. 27A and 27B, an alternative layout for
the bonding connection wires 98 is illustrated. In this case, at
least one, and/or each, of the multiple bonding connection wires 98
may provide electrical connection between a single external bonding
pad 80 on one of the multiple stacks 800 and another external
bonding pad located on another structure such as a packaging
substrate 1000.
[0081] Referring to all drawings and according to various
embodiments of the present disclosure, a bonded assembly is
provided, which comprises: a stack 800 (e.g., a first stack 800A)
containing at least a first semiconductor die 700 bonded to a
second semiconductor die 900 along a stacking direction, first
external bonding pads 80 formed within the first semiconductor die
700, and bonding connection wires 98. Each of the bonding
connection wires 98 extends over a sidewall of the first
semiconductor die 700 and protrudes into the first semiconductor
die 700 through the sidewall of the first semiconductor die 700 to
contact a respective one of the first external bonding pads 80. A
used herein, a stacking direction refers to the direction that is
perpendicular to a bonding interface between two semiconductor
dies.
[0082] In one embodiment, the first semiconductor die 700 comprises
front-side bonding pads 788 having respective planar surfaces that
are perpendicular to the stacking direction, the second
semiconductor die 900 comprises backside bonding pads 988 having
respective planar surfaces that are perpendicular to the stacking
direction, and the backside bonding pads are bonded to the
front-side bonding pads.
[0083] In one embodiment, each of the bonding connection wires 98
comprises: an inter-die connection portion 981 located outside of
the first semiconductor die 700 and extends along the stacking
direction over the sidewall of the first semiconductor die 700; and
a first protrusion portion 98P that protrudes into an opening
through the sidewall of the first semiconductor die 700 and
contacts the respective one of the first external bonding pads
90.
[0084] In one embodiment, the first protrusion portion 98P
comprises a first planar surface that contacts a top surface (which
may be a surface of a UBM stack 80B) of the respective one of the
first external bonding pads 80 that is perpendicular to the
stacking direction, and a second planar surface that is spaced from
the first planar surface by a uniform distance and contacts a
planar dielectric surface of the second semiconductor die 900.
[0085] In one embodiment, the second planar surface may be within a
same two-dimensional plane as bonding surfaces of the front-side
bonding pads 788; and the top surface of the respective one of the
first external bonding pads 80 that is perpendicular to the
stacking direction is offset from a plane including bonding
surfaces of the front-side bonding pads 788 along the stacking
direction by a thickness of a segment of the first protrusion
portion 98P of the bonding connection wire 98.
[0086] In one embodiment, the bonded assembly comprises second
external bonding pads 80 formed within a second stack 800B. Each of
the bonding connection wires 98 provides an electrical connection
between the respective one of the first external bonding pads 80
and a respective one of the second external bonding pads 80 by
extending over the sidewalls of the first stack 800A and second
stack 800B, and protrudes into the second stack 800B to contact a
respective one of the second external bonding pads 80.
[0087] In one embodiment shown in FIG. 24, each of the bonding
connection wires 98 comprises a second protrusion portion 98P that
may protrude into an opening through the sidewall of the second
stack 800B and contacts the respective one of the second external
bonding pads 80.
[0088] In one embodiment, the first protrusion portion 98P may
contact a front-side surface of the respective one of the first
external bonding pads 80 that faces toward the second stack 800B,
and the second protrusion portion 98P may contact a front-side
surface of the respective one of the second external bonding pads
80 that faces away from the first stack 800A.
[0089] In one embodiment, the first protrusion portion 98P may
contact a proximal sidewall 8P of the respective one of the first
external bonding pads 80 that faces toward the inter-die connection
portion 981; and the second protrusion portion 98P may contact a
proximal sidewall 8P of the respective one of the second external
bonding pads 80 that faces toward the inter-die connection portion
981.
[0090] In one embodiment shown in FIG. 19D, the first protrusion
portion 98P may contact a distal sidewall 8D of the respective one
of the first external bonding pads 80 that faces away from the
inter-die connection portion 981; and the second protrusion portion
98P may contact a distal sidewall 8D of the respective one of the
second external bonding pads 80 that faces sway from the inter-die
connection portion 981.
[0091] In one embodiment, the inter-die connection portion 981
continuously extends on the outer sidewall of the first stack 800A
and on the outer sidewall of the second stack 800B between the
first protrusion portion 98P and the second protrusion portion 98P
as illustrated in FIG. 25.
[0092] In one embodiment, the first external bonding pads 80 are
spaced from the sidewall of the first semiconductor die 700 located
in a stack 800 by a lateral offset distance as illustrated in FIGS.
8, 9, 24, and 25.
[0093] In one embodiment, the first external bonding pads 80 may be
physically exposed and have sidewalls that are within a same
two-dimensional plane as the sidewall of the first semiconductor
die 700 as illustrated in FIG. 7. The second exemplary structures
of FIGS. 24 and 25 may be modified to provide this feature.
[0094] In one embodiment, the first external bonding pads 80 may be
offset along the stacking direction from the second semiconductor
die 900 in FIGS. 7-9B by a greater vertical offset distance than
backside surfaces of the front-side bonding pads are from the
second semiconductor die 900.
[0095] In one embodiment, the bonded assembly comprises a packaging
substrate 1000 attached to the first stack 800A, wherein the
bonding connection wires 98 may be bonded to bonding pads of the
packaging substrate 1000 by wire bonding.
[0096] The various structures and methods of the embodiments of the
present disclosure may be used to provide electrical connections
using sidewall surfaces of semiconductor dies in a bonded assembly.
The die size may be reduced since the bonding connection wire hook
up area does not have to extend outward from the adjacent stack
800. Furthermore, expensive through silicon vias (TSVs) may be
omitted. The protrusion portions 98P of the bonding connection
wires 98 may contact sidewalls (8P, 8D) of the external bonding
pads to provide protection against slippage (i.e., pulling out) of
the protrusion portions 98P from the side cavities. By using side
surfaces of a bonded assembly, high density wiring connection may
be provided over the bonded assembly without excessive limitations
on the die size or the total number of dies that may be stacked in
the bonded assembly.
[0097] Although the foregoing refers to particular preferred
embodiments, it will be understood that the disclosure is not so
limited. It will occur to those of ordinary skill in the art that
various modifications may be made to the disclosed embodiments and
that such modifications are intended to be within the scope of the
disclosure. Compatibility is presumed among all embodiments that
are not alternatives of one another. The word "comprise" or
"include" contemplates all embodiments in which the word "consist
essentially of" or the word "consists of" replaces the word
"comprise" or "include," unless explicitly stated otherwise. Where
an embodiment using a particular structure and/or configuration is
illustrated in the present disclosure, it is understood that the
present disclosure may be practiced with any other compatible
structures and/or configurations that are functionally equivalent
provided that such substitutions are not explicitly forbidden or
otherwise known to be impossible to one of ordinary skill in the
art. All of the publications, patent applications and patents cited
herein are incorporated herein by reference in their entirety.
* * * * *