U.S. patent application number 12/973249 was filed with the patent office on 2011-07-21 for package assembly having a semiconductor substrate.
Invention is credited to Chuan-Cheng Cheng, Shiann-Ming Liou, Sehat Sutardja, Chien-Chuan Wei, Albert Wu.
Application Number | 20110175218 12/973249 |
Document ID | / |
Family ID | 44276983 |
Filed Date | 2011-07-21 |
United States Patent
Application |
20110175218 |
Kind Code |
A1 |
Liou; Shiann-Ming ; et
al. |
July 21, 2011 |
PACKAGE ASSEMBLY HAVING A SEMICONDUCTOR SUBSTRATE
Abstract
Embodiments of the present disclosure provide a method that
includes providing a semiconductor substrate comprising a
semiconductor material, forming a dielectric layer on the
semiconductor substrate, forming an interconnect layer on the
dielectric layer, attaching a semiconductor die to the
semiconductor substrate, and electrically coupling an active side
of the semiconductor die to the interconnect layer, the
interconnect layer to route electrical signals of the semiconductor
die. Other embodiments may be described and/or claimed.
Inventors: |
Liou; Shiann-Ming;
(Campbell, CA) ; Sutardja; Sehat; (Los Altos
Hills, CA) ; Wu; Albert; (Palo Alto, CA) ;
Cheng; Chuan-Cheng; (Fremont, CA) ; Wei;
Chien-Chuan; (Los Gatos, CA) |
Family ID: |
44276983 |
Appl. No.: |
12/973249 |
Filed: |
December 20, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61295925 |
Jan 18, 2010 |
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61328556 |
Apr 27, 2010 |
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61333542 |
May 11, 2010 |
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61347156 |
May 21, 2010 |
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61350852 |
Jun 2, 2010 |
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Current U.S.
Class: |
257/712 ;
257/E21.506; 257/E23.08; 438/122 |
Current CPC
Class: |
H01L 2924/12044
20130101; H01L 23/42 20130101; H01L 24/11 20130101; H01L 25/0652
20130101; H01L 2924/01013 20130101; H01L 2924/01078 20130101; H01L
2224/48145 20130101; H01L 2225/06586 20130101; H01L 24/16 20130101;
H01L 2924/18161 20130101; H01L 24/73 20130101; H01L 25/0655
20130101; H01L 2224/14181 20130101; H01L 2224/48091 20130101; H01L
2224/73265 20130101; H01L 2225/0651 20130101; H01L 2924/01006
20130101; H01L 2924/15321 20130101; H01L 2924/181 20130101; H01L
2924/014 20130101; H01L 23/3128 20130101; H01L 25/0657 20130101;
H01L 2924/12035 20130101; H01L 2924/01005 20130101; H01L 2224/32145
20130101; H01L 2924/00014 20130101; H01L 23/147 20130101; H01L
2224/48227 20130101; H01L 2924/01029 20130101; H01L 2924/01079
20130101; H01L 2924/01023 20130101; H01L 2924/12042 20130101; H01L
24/48 20130101; H01L 2224/1403 20130101; H01L 2224/16225 20130101;
H01L 2924/01032 20130101; H01L 2924/19041 20130101; H01L 2224/73207
20130101; H01L 23/49816 20130101; H01L 2224/48137 20130101; H01L
2924/14 20130101; H01L 2225/06506 20130101; H01L 23/49838 20130101;
H01L 2224/73204 20130101; H01L 2924/01033 20130101; H01L 2924/01082
20130101; H01L 2224/32225 20130101; H01L 23/60 20130101; H01L
2224/48091 20130101; H01L 2924/00014 20130101; H01L 2224/73265
20130101; H01L 2224/32145 20130101; H01L 2224/48227 20130101; H01L
2224/73265 20130101; H01L 2224/32145 20130101; H01L 2224/48145
20130101; H01L 2924/00012 20130101; H01L 2224/73265 20130101; H01L
2224/32145 20130101; H01L 2224/48227 20130101; H01L 2924/00012
20130101; H01L 2224/73265 20130101; H01L 2224/32225 20130101; H01L
2224/48227 20130101; H01L 2924/00012 20130101; H01L 2224/73204
20130101; H01L 2224/16225 20130101; H01L 2224/32225 20130101; H01L
2924/00012 20130101; H01L 2924/181 20130101; H01L 2924/00 20130101;
H01L 2924/12035 20130101; H01L 2924/00 20130101; H01L 2924/12042
20130101; H01L 2924/00 20130101; H01L 2924/181 20130101; H01L
2924/00012 20130101; H01L 2924/00014 20130101; H01L 2224/45099
20130101; H01L 2924/00014 20130101; H01L 2224/45015 20130101; H01L
2924/207 20130101; H01L 2224/14181 20130101; H01L 2224/1403
20130101 |
Class at
Publication: |
257/712 ;
438/122; 257/E23.08; 257/E21.506 |
International
Class: |
H01L 23/34 20060101
H01L023/34; H01L 21/60 20060101 H01L021/60 |
Claims
1. A method comprising: providing a semiconductor substrate
comprising a semiconductor material; forming a dielectric layer on
the semiconductor substrate; forming an interconnect layer on the
dielectric layer; attaching a semiconductor die to the
semiconductor substrate; and electrically coupling an active side
of the semiconductor die to the interconnect layer, the
interconnect layer to route electrical signals of the semiconductor
die.
2. The method of claim 1, wherein: the semiconductor die is
attached to the semiconductor substrate in a flip-chip
configuration; and the active side of the semiconductor die is
electrically coupled to the interconnect layer using one or more
bumps.
3. The method of claim 1, wherein: the semiconductor die is
attached to the semiconductor substrate in a wire-bonding
configuration; an inactive side of the semiconductor die is
attached to the semiconductor substrate using an adhesive; and the
active side of the semiconductor die is electrically coupled to the
interconnect layer using one or more bonding wires.
4. The method of claim 1, further comprising: forming a molding
compound to substantially encapsulate the semiconductor die.
5. The method of claim 4, wherein the semiconductor die is attached
to a first side of the semiconductor substrate, the method further
comprising: forming a molding compound to substantially cover a
second side of the semiconductor substrate, the second side being
disposed opposite to the first side of the semiconductor
substrate.
6. The method of claim 1, wherein the semiconductor die is attached
to a first side of the semiconductor substrate, the method further
comprising: thermally coupling a heat spreader to a second side of
the semiconductor substrate, the second side being disposed
opposite to the first side of the semiconductor substrate.
7. The method of claim 1, wherein the semiconductor die is attached
to a first side of the semiconductor substrate, the method further
comprising: removing portions of the semiconductor material from a
second side of the semiconductor substrate to increase a surface
area of the second side, the second side being disposed opposite to
the first side of the semiconductor substrate.
8. The method of claim 1, wherein the semiconductor die is a first
semiconductor die, the method further comprising: electrically
coupling an active side of a second semiconductor die to the
interconnect layer.
9. The method of claim 8, wherein: an inactive side of the second
semiconductor die is attached to the first semiconductor die using
an adhesive; and the active side of the second semiconductor die is
electrically coupled to the interconnect layer using one or more
bonding wires.
10. The method of claim 1, further comprising: forming a
de-coupling capacitor on the semiconductor substrate; and forming
an electro-static discharge (ESD) protection device on the
semiconductor substrate to protect against electro-static
discharge, wherein the de-coupling capacitor and the ESD protection
device are formed prior to attaching the semiconductor die to the
semiconductor substrate.
11. An apparatus comprising: a semiconductor substrate comprising a
semiconductor material; a dielectric layer formed on the
semiconductor substrate; an interconnect layer formed on the
dielectric layer; and a semiconductor die attached to the
semiconductor substrate, wherein an active side of the
semiconductor die is electrically coupled to the interconnect
layer, the interconnect layer to route electrical signals of the
semiconductor die.
12. The apparatus of claim 11, wherein: the semiconductor die is
attached to the semiconductor substrate in a flip-chip
configuration; and the active side of the semiconductor die is
electrically coupled to the interconnect layer using one or more
bumps.
13. The apparatus of claim 11, wherein: the semiconductor die is
attached to the semiconductor substrate in a wirebonding
configuration; an inactive side of the semiconductor die is
attached to the semiconductor substrate using an adhesive; and the
active side of the semiconductor die is electrically coupled to the
interconnect layer using one or more bonding wires.
14. The apparatus of claim 11, further comprising: one or more
package interconnect structures formed on the interconnect layer to
further route the electrical signals of the semiconductor die.
15. The apparatus of claim 14, further comprising: a printed
circuit board, wherein the semiconductor substrate is (i) mounted
on the printed circuit board and (ii) electrically coupled to the
printed circuit board using the one or more package interconnect
structures.
16. The apparatus of claim 11, further comprising: a molding
compound disposed to substantially encapsulate the semiconductor
die.
17. The apparatus of claim 11, wherein the semiconductor die is
attached to a first side of the semiconductor substrate, the
apparatus further comprising: a molding compound disposed to
substantially cover a second side of the semiconductor substrate,
the second side being disposed opposite to the first side of the
semiconductor substrate.
18. The apparatus of claim 11, wherein the semiconductor die is
attached to a first side of the semiconductor substrate, the
apparatus further comprising: a heat spreader thermally coupled to
a second side of the semiconductor substrate, the second side being
disposed opposite to the first side of the semiconductor
substrate.
19. The apparatus of claim 11, wherein the semiconductor die is
attached to a first side of the semiconductor substrate, the
apparatus further comprising: one or more recessed regions formed
in the second side of the semiconductor substrate to increase a
surface area of the second side of the semiconductor substrate.
20. The apparatus of claim 11, wherein the semiconductor die is a
first semiconductor die, the apparatus further comprising: a second
semiconductor die, wherein an active side of the second
semiconductor die is electrically coupled to the interconnect
layer.
21. The apparatus of claim 20, wherein: an inactive side of the
second semiconductor die is attached to the first semiconductor die
using an adhesive; and the active side of the second semiconductor
die is electrically coupled to the interconnect layer using one or
more bonding wires.
22. The apparatus of claim 11, wherein the semiconductor substrate
comprises: a de-coupling capacitor formed on the semiconductor
substrate to reduce noise associated with the electrical signals;
and an electro-static discharge (ESD) protection device formed on
the semiconductor substrate to protect against electro-static
discharge.
23. The apparatus of claim 11, wherein: the semiconductor substrate
comprises silicon; the semiconductor die comprises silicon; the
dielectric layer comprises at least one of silicon dioxide
(SiO.sub.2), silicon nitride (SiN), and silicon oxynitride
(SiO.sub.xN.sub.y); and the interconnect layer comprises a metal.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This disclosure claims priority to U.S. Provisional Patent
Application No. 61/295,925, filed Jan. 18, 2010, and to U.S.
Provisional Patent Application No. 61/328,556, filed Apr. 27, 2010,
and to U.S. Provisional Patent Application No. 61/333,542, filed
May 11, 2010, and to U.S. Provisional. Patent Application No.
61/347,156, filed May 21, 2010, and to U.S. Provisional Patent
Application No, 61/350,852, filed Jun. 2, 2010, the entire
specifications of which are hereby incorporated by reference in
their entirety for all purposes, except for those sections, if any,
that are inconsistent with this specification.
TECHNICAL FIELD
[0002] Embodiments of the present disclosure relate to the field of
integrated circuits, and more particularly, to techniques,
structures, and configurations of semiconductor substrates for
package assemblies.
BACKGROUND
[0003] The background description provided herein is for the
purpose of generally presenting the context of the disclosure. Work
of the presently named inventors, to the extent it is described in
this background section, as well as aspects of the description that
may not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
[0004] Integrated circuit devices, such as transistors, are firmed
on semiconductor dies that continue to scale in size to smaller
dimensions. The shrinking dimensions of the semiconductor dies are
challenging conventional substrate fabrication and/or package
assembly technologies and configurations that are currently used to
route electrical signals to or from the semiconductor die. For
example, laminate substrate technologies may not produce
sufficiently small features on a substrate to correspond with the
finer pitches of interconnects or other signal-routing features
formed on the semiconductor dies.
SUMMARY
[0005] In one embodiment, the present disclosure provides a method
that includes providing a semiconductor substrate comprising a
semiconductor material, forming a dielectric layer on the
semiconductor substrate, forming an interconnect layer on the
dielectric layer, attaching a semiconductor die to the
semiconductor substrate, and electrically coupling an active side
of the semiconductor die to the interconnect layer, the
interconnect layer being configured to route electrical signals of
the semiconductor die.
[0006] In another embodiment, the present disclosure provides an
apparatus including a semiconductor substrate comprising a
semiconductor material, a dielectric layer formed on the
semiconductor substrate, an interconnect layer formed on the
dielectric layer, and a semiconductor die attached to the
semiconductor substrate, wherein an active side of the
semiconductor die is electrically coupled to the interconnect
layer, the interconnect layer to route electrical signals of the
semiconductor die.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the present disclosure will be readily
understood by the following detailed description in conjunction
with the accompanying drawings. To facilitate this description,
like reference numerals designate like structural elements.
Embodiments herein are illustrated by way of example and not by way
of limitation in the figures of the accompanying drawings.
[0008] FIG. 1 schematically illustrates an example package assembly
using a semiconductor substrate.
[0009] FIGS. 2A-2C schematically illustrate a semiconductor
substrate subsequent to various process operations.
[0010] FIGS. 3A-3D schematically illustrate a package assembly
using a semiconductor substrate subsequent to various process
operations.
[0011] FIGS. 4A-4B schematically illustrate the package assembly of
FIG. 3B subsequent to various process operations.
[0012] FIGS. 5A-5G schematically illustrate the package assembly of
FIG. 3A subsequent to various process operations.
[0013] FIGS. 6-11 schematically illustrate various package assembly
configurations using a semiconductor substrate.
[0014] FIG. 12 is a process flow diagram of a method to fabricate a
package assembly using a semiconductor substrate.
[0015] FIG. 13 is a process flow diagram of another method to
fabricate a package assembly using a semiconductor substrate.
[0016] FIG. 14 is a process flow diagram of yet another method to
fabricate a package assembly using a semiconductor substrate.
DETAILED DESCRIPTION
[0017] Embodiments of the present disclosure describe techniques,
structures, and configurations for integrated circuit (IC) package
assemblies (referred to as "package assemblies" herein) using
semiconductor substrates. In the following detailed description,
reference is made to the accompanying drawings which form a part
hereof, wherein like numerals designate like parts throughout.
Other embodiments may be utilized and structural or logical changes
may be made without departing from the scope of the present
disclosure. Therefore, the following detailed description is not to
be taken in a limiting sense, and the scope of embodiments is
defined by the appended claims and their equivalents.
[0018] The description may use perspective-based descriptions such
as up/down, over/under, and/or top/bottom. Such descriptions are
merely used to facilitate the discussion and are not intended to
restrict the application of embodiments described herein to any
particular orientation.
[0019] For the purposes of the present disclosure, the phrase "A/B"
means A or B. For the purposes of the present disclosure, the
phrase "A and/or B" means "(A), (B), or (A and B)." For the
purposes of the present disclosure, the phrase "at least one of A,
B, and C" means "(A), (B), (C), (A and B), (A and C), (B and C), or
(A, B and C)." For the purposes of the present disclosure, the
phrase "(A)B" means "(B) or (AB)" that is, A is an optional
element.
[0020] Various operations are described as multiple discrete
operations in turn, in a manner that is most helpful in
understanding the claimed subject matter. However, the order of
description should not be construed as to imply that these
operations are necessarily order dependent. In particular, these
operations may not be performed in the order of presentation.
Operations described may be performed in a different order than the
described embodiment. Various additional operations may be
performed and/or described operations may be omitted in additional
embodiments.
[0021] The description uses the phrases "in an embodiment," "in
embodiments," or similar language, which may each refer to one or
more of the same or different embodiments. Furthermore, the terms
"comprising," "including," "having," and the like, as used with
respect to embodiments of the present disclosure, are
synonymous.
[0022] FIG. 1 schematically illustrates an example package assembly
100 using a semiconductor substrate 102. As used herein, the
semiconductor substrate 102 refers to a substrate or interposer
that substantially comprises a semiconductor material such as, for
example, silicon (Si). That is, the bulk of the material of the
semiconductor substrate is a semiconductor material. The
semiconductor material can include crystalline and/or amorphous
types of material. In the case of silicon, for example, the silicon
can include single crystal and/or polysilicon types. In other
embodiments, the semiconductor substrate 102 can include other
semiconductor materials such as, for example, germanium, group
III-V materials, or group II-VI materials, that can also benefit
from the principles described herein.
[0023] Generally, the semiconductor substrate 102 is fabricated
using technologies similar to those that are used to fabricate IC
structures on a semiconductor die or chip (e.g., one or more
semiconductor dies 108). For example, well-known patterning
processes (e.g., lithography and/or etch) and deposition processes
for fabricating IC devices on a semiconductor die can be used to
form structures on the semiconductor substrate 102. By using
semiconductor fabrication techniques, the semiconductor substrate
102 can include smaller features than other types of substrates
such as laminate (e.g., organic) substrates. The semiconductor
substrate 102 may facilitate routing of electrical signals for
current semiconductor dies, which continue to shrink in size. For
example, in some embodiments, the semiconductor substrate 102
allows for fine pitch Si-to-Si interconnects and final line routing
between the semiconductor substrate 102 and the one or more
semiconductor dies 108.
[0024] The semiconductor substrate 102 includes a first side, A1,
and a second side, A2, that is disposed opposite to the first side
A1. The first side A1 and the second side A2 generally refer to
opposing surfaces of the semiconductor substrate 102 to facilitate
the description of various configurations described herein and are
not intended to be limited to a particular structure of the
semiconductor substrate 102.
[0025] A dielectric layer 104 is formed on at least the first side
A1 of the semiconductor substrate 102 and can also be formed on the
second side A1 of the semiconductor substrate 102. The dielectric
layer 104 can be formed by depositing an electrically insulative
material such as, for example, silicon dioxide (SiO.sub.2), silicon
nitride (SiN), or silicon oxynitride (SiO.sub.xN.sub.y), where x
and y represent suitable stoichiometric values, to substantially
cover one or more surfaces of the semiconductor substrate 102, as
shown. Other suitable electrically insulative materials can be used
in other embodiments. The dielectric layer 104 can be formed by
using a deposition technique including, for example, physical vapor
deposition (PVD), chemical vapor deposition (CVD), and/or atomic
layer deposition (ALD). Other suitable deposition techniques can be
used in other embodiments.
[0026] The dielectric layer 104 can provide electrical isolation
for features formed on the semiconductor substrate 102. For
example, the dielectric layer 104 can be used to prevent shorting
between electrically conductive features (e.g., one or more
interconnect layers 106) formed on the dielectric layer 104 and the
semiconductor material (e.g., silicon) of the semiconductor
substrate 102. The dielectric layer 104 can further be used as a
gate dielectric in the formation of one or more devices (e.g.,
capacitor 222 of FIG. 2C) on the semiconductor substrate 102.
[0027] One or more interconnect layers 106 are formed on the
dielectric layer 104 to route electrical signals such as, for
example, input/output (I/O) signals and/or power/ground signals, to
and/or from one or more semiconductor dies 108 coupled to the
semiconductor substrate 102. The one or more interconnect layers
106 can be formed by depositing and/or patterning an electrically
conductive material such as, for example, a metal (e.g., copper or
aluminum) or a doped semiconductor material (e.g., doped
polysilicon). Other suitable electrically conductive materials can
be used in other embodiments. The one or more interconnect layers
106 can include a variety of structures to route the electrical
signals such as, for example, pads, lands, or traces. Although not
depicted, a passivation layer comprising an electrically insulative
material such as, for example, polyimide can be deposited on the
one or more interconnect layers 106 and patterned to provide
openings in the passivation layer to facilitate electrical coupling
of the one or more semiconductor dies 108 to the one or more
interconnect layers 106.
[0028] The one or more semiconductor dies 108 are attached to the
first side A1 of the semiconductor substrate 102 using any suitable
configuration including, for example, a flip-chip configuration, as
depicted. Other suitable die-attach configurations such as, for
example, a wire-bonding configuration can be used in other
embodiments.
[0029] In the depicted embodiment, one or more bumps 110 are formed
on the one or more semiconductor dies 108 and bonded to the one or
more interconnect layers 106. The one or more humps 110 generally
comprise an electrically conductive material such as, for example,
solder or other metal to route the electrical signals of the one or
more semiconductor dies 108. According to various embodiments, the
one or more bumps 110 comprise lead, gold, tin, copper, or
lead-free materials, or combinations thereof. The one or more bumps
110 can have a variety of shapes including spherical, cylindrical,
rectangular, or other shapes and can be formed using a bumping
process, such as, for example, a controlled collapse chip connect
(C4) process, stud-bumping, or other suitable bumping process.
[0030] The one or more bumps 110 can be formed on the one or more
semiconductor dies 108 while the one or more semiconductor dies 108
are in either wafer or singulated form. The one or more
semiconductor dies 108 can be attached to the semiconductor
substrate 102 while the semiconductor substrate 102 is in either
wafer or singulated form.
[0031] The one or more semiconductor dies 108 generally have an
active side that includes a surface upon which a plurality of
integrated circuit (IC) devices (not shown) such as transistors for
logic and/or memory are formed and an inactive side that is
disposed opposite to the active side. The active side of the one or
more semiconductor dies 108 is electrically coupled to the one or
more interconnect layers 106. In the depicted embodiment, the
active side of the one or more semiconductor dies 108 is coupled to
the one or more interconnect layers 106 using the one or more bumps
110. In other embodiments, the active side of the one or more
semiconductor dies 108 is electrically coupled to the one or more
interconnect layers 106 using other structures, such as, for
example, one or more bonding wires (e.g., one or more bonding wires
934 of FIG. 9).
[0032] One or more package interconnect structures such as, for
example, one or more solder balls 112 or bumps (e.g., the one or
more bumps 520 of FIG. 5A) can be formed on the one or more
interconnect layers 106 to further route the electrical signals of
the one or more semiconductor dies 108. The one or more package
interconnect structures generally comprise an electrically
conductive material. In some embodiments, the one or more package
interconnect structures are disposed adjacent to a peripheral
portion of the semiconductor substrate 102 and the one or more
semiconductor dies 108 are disposed adjacent to a central portion
of the semiconductor substrate 102, as depicted. The one or more
package interconnect structures can be formed in a variety of
shapes including spherical, planar, polygon, or combinations
thereof.
[0033] According to various embodiments, the one or more
semiconductor dies 108 and the semiconductor substrate 102 are
coupled together to form a package assembly. The package assembly
100 can be electrically coupled to other electrical devices such as
a printed circuit board (PCB) 1.50 (e.g., motherboard) or module
using the one or more package interconnect structures to further
route the electrical signals of the one or more semiconductor dies
108. The one or more package interconnect structures (e.g., the one
or more solder balls 112) can be sized, in some embodiments, to
provide a gap between the one or more semiconductor dies 108 and
the printed circuit board 150, as shown.
[0034] FIGS. 2A-2C schematically illustrate a semiconductor
substrate 102 subsequent to various process operations. Referring
to FIG. 2A, a semiconductor substrate 102 comprising a
semiconductor material is depicted. The semiconductor substrate 102
can include, for example, opposing planar surfaces on the first
side A1 and the second side A2. The semiconductor substrate 102 can
be cut, for example, from an ingot of monocrystalline or
polycrystalline semiconductor material. The semiconductor substrate
102 is generally in wafer form during processing described in
connection with FIGS. 2A-2C, but can be in singulated form.
[0035] Referring to FIG. 2B, the semiconductor substrate 102 is
depicted subsequent formation of a dielectric layer 104 on at least
the first side A1 of the semiconductor substrate 102. The
dielectric layer 104 can be formed on the second side A2 in
addition to the first side A1 in some embodiments.
[0036] Referring to FIG. 2C, the semiconductor substrate 102 is
depicted subsequent to formation of one or more interconnect layers
106 on the dielectric layer 104 that is disposed on the first side
A1 of the semiconductor substrate 102. A passivation layer (not
shown) can be deposited on the one or more interconnect layers 106
and patterned to provide openings for electrically coupling one or
more semiconductor dies (e.g., the one or more semiconductor dies
108 of FIG. 1) to the one or more interconnect layers 106.
[0037] According to various embodiments, one or more devices
including IC devices and/or passive devices can be formed on the
first side A1 of the semiconductor substrate 102. For example, an
example capacitor 222 and an example electro-static discharge (ESD)
protection device 224 can be formed on the semiconductor substrate
102 as depicted in region 275 of the semiconductor substrate 102.
An enlarged view of region 275 is depicted in region 277, which
shows the capacitor 222 and the ESD protection device 224 in
greater detail.
[0038] The capacitor 222 can be, for example, a de-coupling
capacitor to reduce noise associated with the electrical signals
such as power/ground signals of the one or more semiconductor dies.
The capacitor 222 can include, for example, a
metal-oxide-semiconductor (MOS) structure having a source region,
S, and a drain region, D, formed in the semiconductor substrate
102. The source region S and the drain region D can be formed, for
example, by using a doping or implant process to alter the
electrical conductivity of the semiconductor material of the
semiconductor substrate 102. In some embodiments, the source region
S and/or the drain region D is implanted with a dopant to form an
N-type junction in a P-type substrate. A P-type junction in an
N-type substrate can be used in other embodiments. According to
various embodiments, the source region S and the drain region D are
formed prior to forming the dielectric layer 104 of FIG. 2B. The
dielectric layer 104 can function as a gate dielectric for the MOS
structure with the one or more interconnect layers 106 functioning
as a gate electrode of the MOS structure. The gate electrode can
include, for example, doped polysilicon or a metal. Other suitable
techniques can be used to form a capacitor 222 in the semiconductor
substrate 102 in other embodiments.
[0039] The ESD protection device 224 can include, for example, a
diode to protect against electro-static discharge. The ESD
protection device 224 can be formed, for example, by a doping or
implant process to create an N-type region in the semiconductor
substrate 102, which may be a P-type substrate in some embodiments.
A P-type region can be formed in an N-type substrate in other
embodiments. The ESD protection device 224 can be formed, for
example, using techniques associated with forming MOS or bipolar
devices. According to various embodiments, the ESD protection
device 224 includes a complementary MOS (CMOS), bipolar, transient
voltage suppression (TVS) and/or Zener diode or a metal oxide
varistor (MOV). The ESD protection device 224 can include other
suitable devices that protect against electro-static discharge in
other embodiments.
[0040] FIGS. 3A-3D schematically illustrate a package assembly
using a semiconductor substrate 102 subsequent to various process
operations. Referring to FIG. 3A, a package assembly 300A is
depicted subsequent to attaching one or more semiconductor dies 108
to the first side A1 of the semiconductor substrate 102 in a
flip-chip configuration. In some embodiments, one or more humps 110
are formed on the active side of the one or more semiconductor dies
108 and subsequently bonded to the one or more interconnect layers
106 to provide an electrical pathway for the electrical signals of
the one or more semiconductor dies 108. The one or more
semiconductor dies 108 can be attached to the semiconductor
substrate 102 when the semiconductor substrate 102 is in either
wafer form or singulated form.
[0041] Referring to FIG. 3B, a package assembly 300B is depicted
subsequent to depositing an underfill material 314 to substantially
fill a region between the one or more semiconductor dies 108 and
the semiconductor substrate 102. According to various embodiments,
the underfill material 314 is deposited in liquid form by a liquid
dispensing or injection process. The underfill material 314 can
include, for example, an epoxy or other suitable electrically
insulative material. The underfill material 314 generally increases
adhesion between the one or more semiconductor dies 108 and the
semiconductor substrate 102, provides additional electrical
insulation between the one or more semiconductor bumps, and/or
protects the one or more bumps 110 from moisture and oxidation.
[0042] Referring to FIG. 3C, a package assembly 300C is depicted
subsequent to depositing a molding compound 316 to substantially
encapsulate the one or more semiconductor dies 108. The molding
compound 316 generally protects the one or more semiconductor dies
108 from moisture, oxidation, or chipping associated Frith
handling. The molding compound 316 may be used in conjunction with
the underfill material 314, as depicted, in cases where the
materials used for the molding compound 316 do not readily fill the
region (e.g., due to a small pitch of the one or more bumps 110).
According to various embodiments, the molding compound 316 is
formed by depositing a resin (e.g., a thermosetting resin) in solid
form (e.g., a powder) into a mold and applying heat and/or pressure
to fuse the resin. In some embodiments, the molding compound 316 is
not the same material as the underfill material 314.
[0043] Referring to FIG. 3D a package assembly 300D is depicted
subsequent to forming one or more package interconnect structures
such as solder balls 112 or bumps on the interconnect layer 106 to
further route the electrical signals of the one or more
semiconductor dies 108. For example, the solder balls 112 can be
printed, electrically plated, or placed on designated locations
such as bond pads of the one or more interconnect layers 106. The
one or more package interconnect structures can be arranged, for
example, in a single row or in multiple rows and can be formed in a
variety of locations including a central or a peripheral portion of
the package assembly 300D. In some embodiments, the package
assembly 300D is a final package assembly. The final package
assembly is an assembly that is ready to be mounted on another
component such as a printed circuit board (e.g., the printed
circuit board 150 of FIG. 1).
[0044] When the actions described in connection with FIGS. 3B-3D
are performed on a semiconductor substrate 102 in wafer form, the
semiconductor substrate 102 is further singulated by a suitable
singulation process. According to various embodiments, the
semiconductor substrate 102 can be singulated subsequent to the
actions described in connection with FIG. 3A, FIG. 3B, FIG. 3C, or
FIG. 3D.
[0045] In some embodiments, the one or more package interconnect
structures (e.g., the one or more solder balls 112) can be formed
on the semiconductor substrate 102 of the package assembly 300A to
form a final package assembly. The final package assembly using the
package assembly 300A may save costs associated with using an
underfill material and/or molding compound. In some embodiments,
the semiconductor substrate 102 comprises a material that has a
coefficient of thermal expansion (CTE) that is substantially the
same as a material of the one or more semiconductor dies 108. For
example, the semiconductor substrate 102 and the one or more
semiconductor dies 108 may both comprise silicon. In such a case,
the stress of thermal expansion, which is generally mitigated by
the underfill material 314 and/or the molding compound 316, is
reduced because the semiconductor substrate 102 and the one or more
semiconductor dies 108 have the same CTE. Thus, when the CTE is
similar or the same for the semiconductor substrate 102 and the one
or more semiconductor dies 108, the underfill material 314 and/or
the molding compound 316 may not be used at all.
[0046] In some embodiments, the one or more package interconnect
structures (e.g., the one or more solder balls 112) can be formed
on the semiconductor substrate 102 of the package assembly 300B to
form a final package assembly. The final package assembly using the
underfill material 314 may increase reliability of joints such as
solder joints associated with the one or more bumps 110 of the
package assembly 300B.
[0047] FIGS. 4A-4B schematically illustrate the package assembly
300B of FIG. 3B subsequent to various process operations. Although
the package assembly 300B is used as an example to illustrate the
principles of these embodiments, the principles can be suitably
applied to other package assemblies described herein including, for
example, the package assembly 300A.
[0048] Referring to FIG. 4A, a package assembly 400A is depicted
subsequent to the formation of one or more package interconnect
structures (e.g., solder balls 112) on the one or more interconnect
layers 106 and the formation of one or more thermal dissipation
structures (e.g., solder balls 418) on an inactive side of the one
or more semiconductor dies 108, as shown. The one or more package
interconnect structures and the one or more thermal dissipation
structures can include other types of structures such as, for
example, bumps in other embodiments. The one or more thermal
dissipation structures generally comprise a thermally conductive
material such as, for example, metal to provide a thermal path for
heat dissipation. The one or more package interconnect structures
and the one or more thermal dissipation structures can be sized to
have respective surfaces that are substantially coplanar. For
example, the solder balls 112 and the solder balls 418 can be sized
to have a surface that substantially lies in the same plane 419 to
facilitate connection to a substantially planar surface such as a
printed circuit board (e.g., printed circuit board 150 of FIG. 4B).
In some embodiments, the solder balls 112 are larger in size than
the solder balls 418, as depicted.
[0049] The actions described in connection with FIG. 4A can be
performed when the semiconductor substrate 102 is in either wafer
form or singulated form. If in wafer form, the semiconductor
substrate 102 is singulated prior to mounting the package assembly
400A on the printed circuit board.
[0050] Referring to FIG. 4B, a package assembly 400B is depicted
subsequent to attachment of the one or more package interconnect
structures (e.g., the one or more solder balls 112) and the one or
more thermal dissipation structures (e.g., the one or more solder
balls 418) to the printed circuit board 150. According to various
embodiments, the package assembly 400B is mounted on the printed
circuit board 150 using a surface mount technology (SMT).
[0051] FIGS. 5A-5G schematically illustrate the package assembly
300A of FIG. 3A subsequent to various process operations. Although
the package assembly 300A is used as an example to illustrate the
principles of these embodiments, the principles can be suitably
applied to other package assemblies described herein.
[0052] Referring to FIG. 5A, a package assembly 500A is depicted
subsequent to forming one or more package interconnect structures
(e.g., one or more bumps 520) on the one or more interconnect
layers 106. The one or more bumps 520 can be formed, for example,
by printing, plating, or placing the one or more humps 520 on the
one or more interconnect layers 106 of the semiconductor substrate
102. The one or more bumps 520 can be reflowed to form a circular
shape, but is not limited to the circular shape. In other
embodiments, the one or more bumps 520 can have other shapes such
as a planar shape. The one or more bumps 520 can be formed using
any suitable electrically conductive material such as, for example,
lead, gold, tin, copper, or lead-free materials, or combinations
thereof.
[0053] The one or more package interconnect structures can include
other types of structures than the one or more bumps 520 depicted
in FIG. 5A. For example, the one or more package interconnect
structures can include solder balls (e.g., the solder balls 112 of
FIG. 1) in other embodiments.
[0054] Referring to FIG. 5B, a package assembly 500B is depicted
subsequent to depositing a molding compound 316 to substantially
fill a region between the one or more semiconductor dies 108 and
the semiconductor substrate 102. Filling this region with molding
compound 316 may save cost and process steps associated with
fabrication of the semiconductor substrate 102. Generally,
underfill material (e.g., the underfill material 314 of FIG. 3C) is
more costly than the molding compound 316.
[0055] The molding compound 316 is further deposited to
substantially encapsulate the one or more semiconductor dies 108.
In some embodiments, the molding compound 316 is deposited to
substantially cover a surface on the first side A 1 of the
semiconductor substrate 102, which can be in either wafer form or
singulated form. When the semiconductor substrate 102 is in wafer
form, the molding compound 316 can be deposited to overmold an
entire surface of the wafer corresponding with the first side A1 of
the semiconductor substrate 102. The deposited molding compound 316
can be further divided into smaller blocks or regions for
stress/warpage control. For example, portions of the molding
compound 316 can be patterned using well-known etch and/or
lithography processes or otherwise removed at peripheral edges of
each semiconductor substrate unit on the wafer.
[0056] Referring to FIG. 5C, a package assembly 500C is depicted
subsequent to forming one or more openings 526 in the molding
compound 316. According to various embodiments, the one or more
openings 526 are formed to expose the one or more package
interconnect structures (e.g., the one or more bumps 520). The one
or more openings 526 can be formed using a laser ablation or
etching process. In these embodiments, the one or more package
interconnect structures provide an etch stop or laser stop material
during formation of the one or more openings 526.
[0057] Referring to FIG. 5D, a package assembly 500D is depicted
subsequent to depositing an electrically conductive material (e.g.,
one or more solder balls 112) to substantially fill the one or more
openings (e.g., the one or more openings 526 of FIG. 5C). In the
depicted embodiment, one or more solder balls 112 are electrically
coupled to the one or snore bumps 520, which are electrically
coupled to the one or more interconnect layers 106. The one or more
solder balls 112 can, for example, be placed and reflowed to
provide package interconnect structures for the package assembly
500D. That is, the package interconnect structures can include the
one or more solder balls 112 and the one or more bumps 520, coupled
as shown.
[0058] In other embodiments, the one or more solder balls 112 are
formed directly on the one or more interconnect layers 106. That
is, in some embodiments, the one or more bumps 520 are not be
formed at all and the one or more solder balls 112 are directly
bonded to the one or more interconnect layers 106 through the one
or more openings.
[0059] When the one or more bumps 520 are used in conjunction with
the one or more solder balls 112, as depicted, the one or more
solder balls 112 can be smaller than solder balls that are used in
a package assembly that does not use the one or more bumps 520. The
additional height provided by the one or more bumps 520 facilitates
using a smaller size for the one or more solder balls 112 because
less solder ball material is needed to fill the one or more
openings.
[0060] The one or more solder balls 112 can include multiple rows
of solder balls configured to further route the electrical signals
of the one or more semiconductor dies 108. The package interconnect
structures can include other types of structures. For example, in
some embodiments, one or more post structures are formed in the one
or more openings to route the electrical signals of the one or more
semiconductor dies 108.
[0061] In some embodiments, the package interconnect structures
(e.g., the one or more solder balls 112) are attached to a printed
circuit board (e.g., the printed circuit board 150 of FIG. 1).
According to various embodiments, the package assembly 500D is a
final package assembly.
[0062] In some embodiments, the semiconductor substrate 102 is in
wafer form and a backside of the wafer (e.g., the second side A2 of
the semiconductor substrate 102) is thinned to provide a smaller
package assembly. Material can be removed from the backside of the
wafer using, for example, well-known mechanical and/or chemical
wafer thinning processes such as grinding or etching.
[0063] Referring to FIG. 5E, a package assembly 500E is depicted
subsequent to forming a molding compound 316 to substantially cover
the second side A1 of the semiconductor substrate 102. The molding
compound 316 disposed on the second side A2 can be used, for
example, to counterbalance stress associated with the molding
compound 316 disposed on the first side A1 of the semiconductor
substrate 102 and, thus, reduce stress and/or warpage for the
package assembly 500E. In some embodiments, the molding compound
316 is deposited on the second side A2 of the semiconductor
substrate 102 when the semiconductor substrate 102 is in wafer
form, prior to singulation. In some embodiments, the package
assembly 500E is a final package assembly.
[0064] Referring to FIG. 5F, a package assembly 500F is depicted to
show that, in some embodiments, the molding compound 316 is formed
on the first side A1 of the semiconductor substrate 102 to have a
surface that is substantially coplanar with or lower than an
inactive side of the one or more semiconductor dies 108. In an
embodiment, the package assembly 500F is formed by removing
material of the molding compound 316 of the package assembly 500B
of FIG. 5B to expose the one or more semiconductor dies 108. The
material can be removed, for example, by a polishing process. In
another embodiment, the molding compound 316 of the package
assembly 500F is formed by using a mold that is configured to
provide a surface of the molding compound 316 that is substantially
coplanar with or lower than the inactive side of the one or more
semiconductor dies 108. In some embodiments, the package assembly
500F is a final package assembly.
[0065] Referring to FIG. 5G, a package assembly 500G is depicted
subsequent to the formation of one or more thermal dissipation
structures (e.g., solder balls 518) on inactive side of the one or
more semiconductor dies 108, as shown. The one or more thermal
dissipation structures generally comprise a thermally conductive
material such as, for example, metal (e.g., solder) to provide a
thermal path for heat dissipation. The one or more package
interconnect structures (e.g., the one or more solder balls 112)
and the one or more thermal dissipation structures (e.g., the
solder balls 518) can be sized to have surfaces that are
substantially coplanar, as can be seen. For example, the solder
balls 112 and the solder balls 518 can be sized to have a surface
that substantially lies in the same plane 519 to facilitate
connection to a substantially planar surface such as a printed
circuit board (e.g., the printed circuit board 150 of FIG. 4B). In
some embodiments, the solder balls 112 are larger in size than the
solder balls 518, as depicted. The solder balls 112, 518 can be
formed such that they have surfaces that do not lie in the same
plane 519 in other embodiments.
[0066] The one or more solder balls 518 can be formed, for example,
by forming one or more openings in the molding compound 316 of the
package assembly 500B of FIG. 5B or the package assembly 500D of
FIG. 5D to expose the inactive side of the one or more
semiconductor dies 108. The one or more openings can be formed
using a laser ablation or etching process. The inactive side of the
one or more semiconductor dies 108 can function as a laser stop or
etch stop material. Subsequent to formation of the one or more
openings, the one or more solder balls 518 can be deposited to
substantially fill the one or more openings over the one or more
semiconductor dies 108. In some embodiments, the package assembly
500G is a final package assembly.
[0067] FIGS. 6-11 schematically illustrate various package assembly
configurations using a semiconductor substrate 102. Referring to
FIG. 6, a package assembly 600 is depicted subsequent to formation
of a molding compound 316 on the second side A2 of the
semiconductor substrate 102. The molding compound 316 can be
deposited to substantially cover the second side A2 of the
semiconductor substrate 102. The molding compound 316 can be formed
to protect or strengthen the semiconductor substrate 102. For
example, the molding compound 316 can be formed prior to attaching
the one or more semiconductor dies 108 to the semiconductor
substrate 102 to protect the semiconductor substrate 102 from
chipping or other damage that can occur while handling the
semiconductor substrate 102 during package assembly actions
described herein. In some embodiments, the molding compound 316 is
deposited on the second side A2 of the semiconductor substrate 102
when the semiconductor substrate 102 is in wafer form, prior to
singulation.
[0068] Referring to FIG. 7, a package assembly 700 is depicted
subsequent to attachment of a heat spreader 730 to the second side
A2 of the semiconductor substrate 102. The heat spreader 730
includes a structure that facilitates heat removal such as a metal
plate. The heat spreader 730 can be thermally coupled to the second
side A2 of the semiconductor substrate 102 using a thermally
conductive adhesive. The heat spreader 730 can be attached when the
semiconductor substrate 102 is in either wafer form or singulated
form. In other embodiments, the heat spreader 703 can be formed
using deposition processes similar to those used to form the one or
more interconnect layers 106.
[0069] Referring to FIG. 8, a package assembly 800 is depicted
subsequent to removing portions of the semiconductor material from
the second side A2 of the semiconductor substrate 102 to increase a
surface area for improved heat dissipation. According to various
embodiments, one or more recessed regions 832, such as holes or
channels, are formed in a surface on the second side A2 of the
semiconductor substrate 102. The one or more recessed regions 832
can be formed according to any suitable technique including, for
example, an etching process. A profile of the one or more recessed
regions 832 can have other shapes than depicted in other
embodiments. A thermally conductive layer (not shown) such as a
metal layer can be deposited on the surface having the one or more
recessed regions 832 to increase thermal dissipation.
[0070] Referring to FIG. 9A, a package assembly 900A includes one
or more semiconductor dies 108 attached to the semiconductor
substrate 102 in a wire-bonding configuration. An inactive side of
the one or more semiconductor dies 108 is attached to the first
side A1 of the semiconductor substrate 102 using an adhesive and an
active side of the one or more semiconductor dies is electrically
coupled to the one or more interconnect layers 106 using one or
more bonding wires 934. The adhesive can include any suitable die
attach material such as an epoxy. The one or more bonding wires 934
generally comprise an electrically conductive material, such as a
metal, to route the electrical signals of the one or more
semiconductor dies 108. The one or more bonding wires 934 can be
formed using, for example, a ball-bonding or wedge-bonding
process.
[0071] In an embodiment, a bonding wire 934a is formed to
electrically couple an active side of a first semiconductor die to
an active side of a second semiconductor die, as shown. The one or
more bonding wires 934 can further include a bonding wire 934b that
electrically couples an active side of a semiconductor die to the
one or more interconnect layers 106 disposed between the first
semiconductor die and the second semiconductor die. A molding
compound 316 is formed to substantially encapsulate the one or more
semiconductor dies 108 and the one or more bonding wires 934, as
shown.
[0072] FIG. 9B illustrates a package assembly 900B that is similar
to the package assembly 900A as shown in FIG. 9A. In the package
assembly 900B, vias 938, such as through-silicon vias, that are
filled with conducting materials are used to provide electrical
connections from the semiconductor dies 108 to external components.
These vias 938 may be used to provide power and ground
connections.
[0073] Referring to FIG. 10A, a package assembly 1000A includes one
or more semiconductor dies 108A,B attached to the semiconductor
substrate 102 in a mixed flip-chip and wire-bonding configuration.
For example, a first semiconductor die of the one or more
semiconductor dies 108A,B is attached to the semiconductor
substrate 102 in a flip-chip configuration using one or more bumps
110 and a second semiconductor die of the one or more semiconductor
dies 108A,B is attached to the semiconductor substrate 102 in a
wire-bonding configuration using one or more bonding wires 934. A
molding compound 316 is formed to substantially encapsulate the one
or more semiconductor dies 108A,B and the one or more bonding wires
934, as shown.
[0074] FIG. 10B illustrates a package assembly 1000B that is
similar to the package assembly 1000A as shown in FIG. 10A. In the
package assembly 1000B, vias 938, such as through-silicon vias,
that are filled with conducting materials are used to provide
electrical connections from the semiconductor die 108B to external
components. These vias 938 may be used to provide power and ground
connections.
[0075] Referring to FIG. 11, a package assembly 1100 includes one
or more semiconductor dies 108 attached to the semiconductor
substrate 102 in a stacked flip-chip and wire-bonding
configuration. A first semiconductor die of the one or more
semiconductor dies 108 is attached to the semiconductor substrate
102 in a flip-chip configuration. An active side of the first
semiconductor die is electrically coupled to the one or more
interconnect layers 106 using one or more bumps 110, as shown. An
inactive side of a second semiconductor die of the one or more
semiconductor dies 108 is attached to first semiconductor die using
an adhesive 936, as shown. In some embodiments, a spacer (not
shown) such as dummy silicon can be positioned between the first
and second semiconductor dies. An active side of the second
semiconductor die is electrically coupled to the one or more
interconnect layers 106 using one or more bonding wires 934. In
other embodiments, vias (not shown), such as through-silicon vias,
that are filled with conducting materials may be used to couple the
active side of the second semiconductor die to external components
through the molding compound 316. The vias may be used to provide
power and ground connections.
[0076] In some embodiments, the active side of the second
semiconductor die is electrically coupled to the one or more
interconnect layers 106 by using a bonding wire 934c to
electrically couple the active side of the second semiconductor die
to the inactive side of the first semiconductor die and using a
bonding wire 934d to electrically couple the first bonding wire
934c to the one or more interconnect layers 106. A molding compound
316 is formed to substantially encapsulate the one or more
semiconductor dies 108 and the one or more bonding wires 934, as
shown. Although not shown, in other embodiments, a bottom
semiconductor die of the one or more semiconductor dies 108 can be
coupled to the semiconductor substrate 102 in a wirebonding
configuration and a top semiconductor die of the one or more
semiconductor dies 108 can be coupled to the bottom semiconductor
die in a flip-chip configuration.
[0077] Techniques and con figurations described in connection with
FIGS. 6-11 can be suitably combined with other embodiments
described herein. For example, in some embodiments, the techniques
and configurations described for the package assemblies of FIGS.
6-8 can be performed on the package assemblies of FIG. 1, FIGS.
3A-3D, FIGS. 4A-4B, FIGS. 5A-5G, or FIGS. 9-11. In some
embodiments, the techniques and configurations described for the
package assemblies of FIGS. 9-11 can be performed, for example, on
the package assemblies of FIG. 1, FIGS. 3A-3D, FIGS. 4A-4B, FIGS.
5A-5G, or FIGS. 6-8. Other suitable combinations of the techniques
and configurations described herein can be used in other
embodiments.
[0078] FIG. 12 is a process flow diagram of a method 1200 to
fabricate a package assembly (e.g., the package assembly 100 of
FIG. 1) using a semiconductor substrate (e.g., the semiconductor
substrate 102 of FIG. 1). At 1202, the method 1200 includes
providing a semiconductor substrate comprising a semiconductor
material. The semiconductor substrate generally has a first side
(e.g., the first side A1 of FIG. 2A) and a second side (e.g., the
second side A2 of FIG. 2A) that is disposed opposite to the first
side. In some embodiments, one or more devices are formed on the
first side (e.g., the first side A1 of FIG. 1) of the semiconductor
substrate prior to attaching the semiconductor die to the
semiconductor substrate. For example, a capacitor (e.g., the
capacitor 222 of FIG. 2C) or an ESD protection device (e.g., the
ESD protection device 224 of FIG. 2C) can be formed on the first
side of the semiconductor substrate. The one or more devices can be
formed using techniques described in connection with FIG. 2C and
further described in connection with 1204 and 1206 of method
1200.
[0079] At 1204, the method 1200 further includes forming a
dielectric layer (e.g., the dielectric layer 104 of FIG. 1) on at
least one side (e.g., the first side A1) of the semiconductor
substrate. The dielectric layer can further be formed on the
opposite side (e.g., the second side A2) of the semiconductor
substrate in some embodiments.
[0080] The dielectric layer 104 can be formed by depositing an
electrically insulative material such as, for example, silicon
dioxide (SiO.sub.2), silicon nitride (SiN), or silicon oxynitride
(SiO.sub.xN.sub.y) to substantially cover one or more surfaces of
the semiconductor substrate 102, as shown. Other suitable
electrically insulative materials can be used in other
embodiments.
[0081] The dielectric layer 104 can be formed by using a suitable
deposition technique including, for example, physical vapor
deposition (PVD), chemical vapor deposition (CVD), and/or atomic
layer deposition (ALD). Other suitable deposition techniques can be
used in other embodiments. The dielectric layer 104 can be used as
a dielectric (e.g., gate dielectric) in the formation of the one or
more devices (e.g., capacitor 222 or ESD protection device 224 of
FIG. 2C) on the semiconductor substrate 102.
[0082] At 1206, the method 1200 further includes forming one or
more interconnect layers (e.g., the one or more interconnect layers
106 of FIG. 1) on the dielectric layer on the first side of the
semiconductor substrate. The one or more interconnect layers can be
used to route electrical signals such as, for example, input/output
(I/O) signals and/or power/ground signals, to and/or from one or
more semiconductor dies (e.g., the one or more semiconductor dies
108 of FIG. 1).
[0083] The one or more interconnect layers can be formed by
depositing and/or patterning an electrically conductive material
such as, for example, a metal (e.g., copper or aluminum) or a doped
semiconductor material (e.g., doped polysilicon). Other suitable
electrically conductive materials can be used in other
embodiments.
[0084] The one or more interconnect layers can include a variety of
structures to route the electrical signals such as, for example,
pads, lands, or traces. A passivation layer comprising an
electrically insulative material such as, for example, polyimide
can be deposited on the one or more interconnect layers and
patterned to provide openings in the passivation layer to
facilitate electrical coupling of the one or more semiconductor
dies to the one or more interconnect layers.
[0085] The one or more interconnect layers can be used as an
electrode material in the formation of the one or more devices on
the semiconductor substrate. For example, the electrode material
can serve as a gate electrode for the one or more devices.
[0086] At 1208, the method 1200 further includes attaching a
semiconductor die (e.g., the one or more semiconductor dies 108 of
FIG. 1) to the semiconductor substrate. As described herein, one or
more semiconductor dies can be attached to the first side of the
semiconductor substrate in a variety of configurations.
[0087] In an embodiment, the semiconductor die is attached to the
first side of the semiconductor substrate in a flip-chip
configuration (e.g., as shown in the package assembly 100 of FIG.
1). In the flip-chip configuration, the active side of the
semiconductor die is generally attached to the first side of the
semiconductor substrate using one or more bumps (e.g., the one or
more bumps 110 of FIG. 1).
[0088] In another embodiment, the semiconductor die is attached to
the first side of the semiconductor substrate in a wire-bonding
configuration (e.g., as shown in the package assembly 900 of FIG.
9). In the wire-bonding configuration, an inactive side of the
semiconductor die is attached to the first side of the
semiconductor using an adhesive.
[0089] In yet another embodiment, the semiconductor die is attached
to the semiconductor substrate in a flip-chip configuration and
another semiconductor die is attached to the semiconductor
substrate in a wire-bonding configuration (e.g., as shown in the
package assembly 1000 of FIG. 10). In still yet another embodiment,
an active side of the semiconductor die is attached to the first
side of the semiconductor substrate in a flip-chip configuration
and an inactive side of another semiconductor die is attached to
the semiconductor die using an adhesive (e.g., as shown in the
package assembly 1100 of FIG. 11).
[0090] At 1210, the method 1200 further includes electrically
coupling the active side of the semiconductor die to the one or
more interconnect layers. In an embodiment, the active side of the
semiconductor die is electrically coupled to the one or more
interconnect layers using the one or more bumps. In another
embodiment, the active side of the semiconductor die is
electrically coupled to the one or more interconnect layers using
one or more bonding wires (e.g., the one or more bonding wires 934
of FIG. 9). Combinations of these techniques can be used in other
embodiments.
[0091] At 1212, the method 1200 further includes depositing an
underfill material (e.g., the underfill material 314 of FIG. 3B)
and/or a molding compound (e.g., the molding compound 316 of FIG.
3C, 5B, or 9). The underfill material is generally deposited to
substantially fill a regio between the semiconductor die and the
semiconductor substrate. According to various embodiments, the
underfill material is en deposited in liquid form by a liquid
dispensing or infection process. The underfill material can
include, for example, an epoxy or other suitable electrically
insulative material.
[0092] The molding compound is generally deposited to substantially
encapsulate the semiconductor die. In a wire-bonding configuration,
the molding compound is deposited to su substantially encapsulate
the one or more bonding wires. According to various embodiments,
the molding compound is formed by depositing a resin (e.g., a
thermosetting resin) in solid form (e.g., a powder) into a mold and
applying heat and/or pressure to fuse the resin. In some
embodiments, the molding compound is not the same material as the
underfill material.
[0093] In a flip-chip configuration, the molding compound can be
used in conjunction with the underfill material (e.g., as shown in
FIG. 3C). In other embodiments of the flip-chip configuration, the
molding compound can be deposited to fill the underfill region.
That is, in some embodiments, the underfill material is not used
and the molding compound is deposited to substantially fill a
region between the semiconductor die and the semiconductor
substrate (e.g., as shown in FIG. 5B). In some embodiments, the
molding compound is formed to cover only a portion of the first
side of the semiconductor substrate (e.g., as shown in FIG. 3C). In
other embodiments, the molding compound is formed to substantially
cover the entire first side of the semiconductor substrate (e.g.,
as shown in FIG. 5B).
[0094] At 1214, the method 1200 further includes forming one or
more package interconnect structures on the one or more
interconnect layers to route electrical signals of the
semiconductor die to and/or from the semiconductor substrate. In
some embodiments, the one or more package interconnect structures
include one or more solder balls (e.g., the one or more solder
balls 112 of FIG. 3D or 5D). The one or more solder balls can be
formed, for example, by printing, plating, or placing the one or
more solder balls on the one or more interconnect layers of the
semiconductor substrate. A reflow process can be used to form a
connection between the one or more solder balls and the one or more
interconnect layers. In some embodiments, the one or more solder
balls can be attached or electrically coupled to the one or more
interconnect layers through one or more openings (e.g., the one or
more openings 526 of FIG. 5C) formed in the molding compound as
described herein.
[0095] In some embodiments, the one or more package interconnect
structures include one or more bumps (e.g., the one or more bumps
520 of FIG. 5A). The one or more bumps can be formed, for example,
by printing, plating, or placing the one or more bumps on the one
or more interconnect layers of the semiconductor substrate. The one
or more bumps can be reflowed to form a circular shape. The one or
more bumps can have other shapes such as a planar shape. The one or
more bumps can be formed using any suitable electrically conductive
material such as, for example, lead, gold, tin, copper, or
lead-free materials, or combinations thereof. The one or more
package interconnect structures can include combinations of the one
or more bumps and the one or more solder balls (e.g., as shown in
FIG. 5D). The one or more package interconnect structures can be
electrically coupled to a printed circuit hoard (e.g., the printed
circuit board 150 of FIG. 1).
[0096] At 1216, the method 1200 further includes performing
additional operations to increase thermal dissipation,
protect/strengthen, counter-balance, and/or reduce warpage of the
semiconductor substrate. In some embodiments, one or more thermal
dissipation structures (e.g., the one or more solder balls 418 or
518 of respective FIG. 4A or 5G) are formed on an inactive side of
a semiconductor die to provide a thermal path for heat dissipation
away from the semiconductor die, as described herein. The one or
more thermal dissipation structures for heat dissipation can formed
simultaneously as the one or more package interconnects and can be
subsequently attached to a printed circuit board (e.g., the printed
circuit board 150 of FIG. 4B) during a surface mount process to
couple the one or more package interconnects to the printed circuit
board.
[0097] In some embodiments, a heat spreader (e.g., the heat
spreader 730 of FIG. 7) is thermally coupled to the second side of
the substrate. The heat spreader can be attached, for example, by
using a thermally conductive compound. In other embodiments, one or
more recessed regions (e.g., the one or more recessed regions 832
of FIG. 8) are formed by removing portions of the semiconductor
material from the second side of the semiconductor substrate to
increase a surface area of the second side. The increased surface
area facilitates heat removal away from the second side of the
semiconductor substrate.
[0098] In an embodiment, a molding compound is formed to
substantially cover the second side of the semiconductor substrate
(e.g., as shown in FIG. 6). The molding compound can be used to
strengthen and/or protect the semiconductor substrate against
chipping or other environmental harm. In some embodiments, the
molding compound is formed on the second side of the semiconductor
substrate to counter-balance and/or prevent warpage associated with
a molding compound formed on the first side of the semiconductor
substrate (e.g., as shown in FIG. 5E). The actions described in
connection with method 1200 can include other suitable embodiments
for techniques described elsewhere in this description.
[0099] FIG. 13 is a process flow diagram of another method 1300 to
fabricate a package assembly (e.g., the package assembly 400B of
FIG. 4B) using a semiconductor substrate (e.g., the semiconductor
substrate 102 of FIG. 4B). At 1302, 1304, and 1306, the method 1300
respectively includes providing a semiconductor substrate
comprising a semiconductor material, forming a dielectric layer on
at least one side of the semiconductor substrate, and forming one
or more interconnect layers on the dielectric layer, which may
comport with embodiments already described in connection with 1202,
1204, and 1206 of method 1200.
[0100] At 1308, the method 1300 further includes coupling one or
more semiconductor dies (e.g., the semiconductor dies 108 of FIG.
3A) to the interconnect layer using one or more bumps (e.g., the
one or more bumps 110 of FIG. 3A). The one or more semiconductor
dies can be configured, for example, in a flip-chip configuration
where an active side of the semiconductor die is coupled to the
semiconductor substrate using the one or more bumps.
[0101] At 1310, the method 1300 further includes depositing an
underfill material (e.g., the underfill material 314 of FIG. 3B) to
substantially fill a region between the semiconductor die and the
semiconductor substrate. According to various embodiments, the
underfill material is deposited in liquid form by a liquid
dispensing or injection process. A molding compound (e.g., the
molding compound 316 of FIG. 3C) can also be formed to
substantially encapsulate the one or more semiconductor dies. The
underfill material and the molding compound generally comport with
embodiments described herein.
[0102] At 1312, the method 1300 further includes forming one or
more package interconnect structures (e.g., the solder balls 112 of
FIG. 3D) and/or one or more thermal dissipation structures (e.g.,
the one or more solder balls 418 of FIG. 4A). The one or more
package interconnect structures are electrically coupled to the one
or more interconnect layers. In some embodiments, the one or more
package interconnect structures are formed on the one or more
interconnect layers. The one or more thermal dissipation structures
are generally formed on an inactive side of the one or more
semiconductor dies to provide a thermal path for heat dissipation.
The one or more package interconnect structures and the one or more
thermal dissipation structures can be sized to have respective
surfaces that are substantially coplanar (e.g., plane 419 of FIG.
4A).
[0103] At 1314, the method 1300 further includes coupling the one
or more package interconnect structures and/or the one or more
thermal dissipation structures to a printed circuit board (e.g.,
the printed circuit board 150 of FIG. 4B). The printed circuit
board can be a motherboard in some embodiments. The one or more
package interconnect structures and/or the one or more thermal
dissipation structures can be coupled to other electronic devices,
such as another package assembly, in other embodiments.
[0104] FIG. 14 is a process flow diagram of yet another method 1400
to fabricate a package assembly (e.g., the package assembly 500G of
FIG. 5G) using a semiconductor substrate (e.g., the semiconductor
substrate 102 of FIG. 5G). At 1402, 1404, and 1406, the method 1400
respectively includes providing a semiconductor substrate
comprising a semiconductor material, forming a dielectric layer on
at least one side of the semiconductor substrate, and forming one
or more interconnect layers on the dielectric layer, which may
comport with embodiments already described in connection with 1202,
1204, and 1206 of method 1200.
[0105] At 1408, the method 1400 further includes coupling one or
more semiconductor dies (e.g., the semiconductor dies 108 of FIG.
5A) to the interconnect layer using one or more bumps (e.g., the
one or more humps 110 of FIG. 5A). The one or more semiconductor
dies can be configured, for example, in a flip-chip configuration
where an active side of the semiconductor die is coupled to the
semiconductor substrate using the one or more bumps.
[0106] At 1410, the method 1400 further includes forming one or
more additional bumps (e.g., the one or more humps 520 of FIG. 5A)
on the one or more interconnect layers in some embodiments. The one
or more additional bumps are generally formed prior to the molding
compound being deposited.
[0107] At 1412, the method 1400 further includes depositing a
molding compound the molding compound 316 of FIG. 5B) to fill a
region between the semiconductor die and the semiconductor
substrate. In some embodiments, the molding compound is deposited
to substantially encapsulate the one or more semiconductor dies. A
portion of the molding compound can be recessed by well-known
mechanical and/or chemical processes to expose a surface of the one
or more semiconductor dies.
[0108] The molding compound can be formed by depositing a resin of
solid form into a mold and subsequently applying heat and/or
pressure to fuse the resin. According to various embodiments, the
molding compound is deposited when the semiconductor substrate is
in wafer form to overmold an entire surface of the wafer. The
deposited molding compound can be divided into smaller blocks or
regions to reduce stress between the molding compound and the
wafer.
[0109] In some embodiments where the semiconductor die is coupled
to a first side of the semiconductor substrate, a molding compound
is formed to substantially cover a second side of the semiconductor
substrate, the second side being disposed opposite to the first
side of the semiconductor substrate. The molding compound can be
used in this manner to reduce stress and/or warpage associated with
a molding compound disposed on the first side of the semiconductor
substrate.
[0110] At 1414, the method 1400 further includes forming one or
more package interconnect structures (e.g., the solder balls 112 of
FIG. 5G) and/or one or more thermal dissipation structures (e.g.,
the one or more solder balls 518 of FIG. 5G). The one or more
package interconnect structures are electrically coupled to the one
or more interconnect layers. In some embodiments, the one or more
package interconnect structures are formed on the one or more
interconnect layers. In other embodiments where the one or more
additional bumps (e.g., the one or more bumps 520 of FIG. 5D) are
formed, the one or more package interconnect structures are formed
on the one or more additional bumps. For example, one or more
openings (e.g., the one or more openings 526 of FIG. 5C) can be
formed in the molding compound using an etch or laser process to
expose the one or more additional bumps. The one or more additional
bumps can function as a laser or etch stop material. Subsequently,
the one or more package interconnect structures can be formed on
the exposed one or more additional humps within the one or more
openings.
[0111] The one or more thermal dissipation structures are generally
formed on an inactive side of the one or more semiconductor dies to
provide a thermal path for heat dissipation. One or more openings
can be formed in the molding compound to expose the inactive side
of the one or more semiconductor dies to allow formation of the one
or more thermal dissipation structures on the one or more
semiconductor dies. The one or more package interconnect structures
and the one or more thermal dissipation structures can be sized to
have respective surfaces that are substantially coplanar (e.g.,
plane 519 of FIG. 5G). The semiconductor substrate can be
subsequently thinned by grinding or etching processes.
[0112] At 1416, the method 1400 further includes coupling the one
or more package interconnect structures and/or the one or more
thermal dissipation structures to a printed circuit board (e.g.,
the printed circuit board 150 of FIG. 4B). The printed circuit
board can be a motherboard in some embodiments. The one or more
package interconnect structures and/or the one or more thermal
dissipation structures can be coupled to other electronic devices,
such as another package assembly, in other embodiments.
[0113] Although certain embodiments have been illustrated and
described herein, a wide variety of alternate and/or equivalent
embodiments or implementations calculated to achieve the same
purposes may be substituted for the embodiments illustrated and
described without departing from the scope of the present
disclosure. This disclosure is intended to cover any adaptations or
variations of the embodiments discussed herein. Therefore, it is
manifestly intended that embodiments described herein be limited
only by the claims and the equivalents thereof.
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