U.S. patent application number 16/276866 was filed with the patent office on 2019-06-13 for method of reconstituted substrate formation for advanced packaging applications.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Han-Wen CHEN, Kyuil CHO, Boyi FU, Roman GOUK, Yu GU, Colin Costano NEIKIRK, Guan Huei SEE, Arvind SUNDARRAJAN, Steven VERHAVERBEKE.
Application Number | 20190181019 16/276866 |
Document ID | / |
Family ID | 64692712 |
Filed Date | 2019-06-13 |
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United States Patent
Application |
20190181019 |
Kind Code |
A1 |
CHEN; Han-Wen ; et
al. |
June 13, 2019 |
METHOD OF RECONSTITUTED SUBSTRATE FORMATION FOR ADVANCED PACKAGING
APPLICATIONS
Abstract
Embodiments of the present disclosure generally describe methods
for minimizing the occurrence and the extent of die shift during
the formation of a reconstituted substrate in fan-out wafer level
packaging processes and reconstituted substrates formed therefrom.
Die shift is a process defect that occurs when a die (device) moves
from its intended position within a reconstituted substrate during
the formation thereof. Generally, the reconstituted substrates
disclosed herein include a device immobilization layer and/or a
plurality of device immobilization beads over and/or adjacent to a
plurality of singular devices (individual dies), and a cured epoxy
molding compound formed there over. The device immobilization layer
and/or the plurality of device immobilization beads immobilize the
plurality of singular devices and prevents them from shifting on
the carrier substrate during the molding process.
Inventors: |
CHEN; Han-Wen; (Cupertino,
CA) ; VERHAVERBEKE; Steven; (San Francisco, CA)
; GOUK; Roman; (San Jose, CA) ; SEE; Guan
Huei; (Singapore, SG) ; GU; Yu; (Singapore,
SG) ; SUNDARRAJAN; Arvind; (Singapore, SG) ;
CHO; Kyuil; (Santa Clara, CA) ; NEIKIRK; Colin
Costano; (Sunnyvale, CA) ; FU; Boyi; (San
Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
64692712 |
Appl. No.: |
16/276866 |
Filed: |
February 15, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15840900 |
Dec 13, 2017 |
10211072 |
|
|
16276866 |
|
|
|
|
62524298 |
Jun 23, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/568 20130101;
H01L 2224/04105 20130101; H01L 23/3135 20130101; H01L 21/0274
20130101; H01L 23/13 20130101; H01L 24/96 20130101; H01L 21/561
20130101; H01L 2224/12105 20130101; H01L 21/311 20130101; H01L
21/02118 20130101; H01L 21/4825 20130101; H01L 23/5389 20130101;
G03F 7/0002 20130101; H01L 21/02277 20130101; H01L 21/02107
20130101 |
International
Class: |
H01L 21/56 20060101
H01L021/56; H01L 23/31 20060101 H01L023/31; H01L 23/538 20060101
H01L023/538; H01L 23/13 20060101 H01L023/13; H01L 23/00 20060101
H01L023/00; H01L 21/48 20060101 H01L021/48; H01L 21/311 20060101
H01L021/311; H01L 21/027 20060101 H01L021/027; H01L 21/02 20060101
H01L021/02; G03F 7/00 20060101 G03F007/00 |
Claims
1. A substrate, comprising: a reconstituted substrate, comprising:
a plurality of devices disposed in a cured molding compound; and a
device immobilization layer interposed between the plurality of
devices and the molding compound, wherein the device immobilization
layer comprises a polymerized reaction product of one or more
monomers and one or more catalytically dissociated initiator
precursors.
2. The substrate of claim 1, further comprising an electrostatic
discharge layer disposed between the cured molding compound and
individual ones of the plurality of devices.
3. The substrate of claim 1, further comprising one or more
redistribution layers disposed on the reconstituted substrate,
wherein each of the one or more redistribution layers comprises a
dielectric material layer having a plurality of interconnect
structures disposed therethrough.
4. The substrate of claim 1, wherein the one or more monomers are
selected from the group consisting of ethyleneglycol diacrylate,
t-butylacrylate, N,N-dimethylacrylamide, vinylimidazole,
1-3-diethynylbenzene, 4-vinyl pyridine, poly vinyl pyridine, poly
4-vinyl pyridine, polyphenylacetylene,
N,N-dimethylaminoethylmethacrylate, divinylbenzene, poly
divinylbenzene, glycidyl methacrylate, poly thiophene,
ethyleneglycol dimethacrylate, tetrafluoroethylene,
dimethylaminomethylstyrene, perfluoroalkyl ethylmethacrylate,
trivinyltrimethoxy-cyclotrisiloxane, furfuryl methacrylate,
cyclohexyl methacrylate-co-ethylene glycol dimethacrylate,
pentafluorophenyl methacrylate-co-ethylene glycol diacrylate,
2-hydroxyethyl methacrylate, methacrylic acid,
3,4-ethylenedioxythiophene, and combinations thereof.
5. The substrate of claim 1, wherein the one or more initiator
precursors are selected from the group consisting of hydrogen
peroxide, alkyl peroxides, aryl peroxides, hydroperoxides,
halogens, azo compounds, and combinations thereof.
6. The substrate of claim 1, wherein the device immobilization
layer comprises a continuous layer interposed between the cured
molding compound and the plurality of devices disposed therein.
7. The substrate of claim 1, wherein the device immobilization
layer comprises a discontinuous layer comprising a plurality of
immobilization patches interposed between the cured molding
compound and individual ones of the plurality of devices.
8. The substrate of claim 1, wherein the polymerized reaction
product comprises poly(glycidyl methacrylate-co-divinylbenzene),
poly(glycidyl methacrylate-co-methacrylamide), poly(ethyleneglycol
diacrylate), poly(t-butylacrylate), poly N,N-dimethylacrylamide,
poly(vinylimidazole), poly(1-3-diethynylbenzene),
poly(phenylacetylene), poly(N,N-dimethylaminoethylmethacrylate)
(p(DMAM), poly (divinylbenzene), poly(glycidyl methacrylate)
(p(GMA)), poly (ethyleneglycol dimethacrylate), poly
(tetrafluoroethylene), poly(tetrafluoroethylene) (PTFE),
poly(dimethylaminomethylstyrene) (p(DMAMS), poly(thiophene),
poly(vinylpyridine), poly(perfluoroalkyl ethylmethacrylate),
poly(trivinyltrimethoxy-cyclotrisiloxane), poly(furfuryl
methacrylate), poly(cyclohexyl methacrylate-co-ethylene glycol
dimethacrylate), poly(pentafluorophenyl methacrylate-co-ethylene
glycol diacrylate), poly(2-hydroxyethyl methacrylate-co-ethylene
glycol diacrylate), poly(methacrylic acid-co-ethylene glycol
dimethacrylate), poly(3,4-ethylenedioxythiophene), or combinations
thereof.
9. The substrate of claim 8, wherein the polymerized reaction
product comprises poly(glycidyl methacrylate) (p(GMA)).
10. The substrate of claim 1, wherein the device immobilization
layer has a thickness between about 0.5 .mu.m and about 100
.mu.m.
11. A substrate, comprising: a reconstituted substrate, comprising:
a plurality of devices disposed in a cured molding compound, each
of the plurality of devices comprising a first surface having one
or more bond pads disposed therein and one or more second surfaces
which are substantially normal to the first surface; and a
plurality of device immobilization beads interposed between
individual ones of the plurality of devices and the cured molding
compound, wherein each of the device immobilization beads cover at
least portions of the one or more second surfaces, and wherein
portions of each of the respective device immobilization beads
extend laterally outward from the first surfaces of the devices
disposed adjacent thereto.
12. The substrate of claim 11, further comprising an electrostatic
discharge layer interposed between the cured molding compound and
the plurality of devices.
13. The substrate of claim 11, further comprising one or more
redistribution layers disposed on the reconstituted substrate,
wherein each of the one or more redistribution layers comprises a
dielectric material layer having a plurality of interconnect
structures disposed therethrough.
14. The substrate of claim 11, wherein the plurality of device
immobilization beads comprise a UV cured reaction product of a
mixture of one or more functional polymers, functional oligomers,
functional monomers, or reactive diluents.
15. The substrate of claim 14, wherein the plurality of device
immobilization beads comprise a UV cured reaction product of a
mixture comprising one or a combination of multifunctional
acrylates, monofunctional acrylate oligomers, multifunctional
acrylate oligomers, monofunctional acrylate monomers, and
multifunctional acrylate monomers.
16. The reconstituted substrate of claim 11, wherein the device
immobilization beads are located at one or more corners of each
respective device, are located between corners of each respective
device, a combination thereof, or form a continuous surface about a
perimeter of each respective device.
17. The substrate of claim 16, wherein the plurality of device
immobilization beads form a continuous surface about the perimeter
of the device.
18. A packaged device, comprising: a device disposed in a cured
molding compound, the device comprising a first surface having one
or more bond pads disposed therein and one or more second surfaces
which are substantially normal to the first surface; a plurality of
device immobilization beads interposed between the device and the
cured molding compound, wherein each of the device immobilization
beads cover at least a portion of the one or more second surfaces
of the device, and wherein portions of each of the device
immobilization beads extend laterally outward from the first
surfaces of the devices disposed adjacent thereto; and one or more
redistribution layers disposed on the first surface of the device,
wherein each of the one or more redistribution layers comprises a
dielectric material layer having a plurality of interconnect
structures disposed therethrough.
19. The packaged device of claim 18, wherein the device
immobilization beads are located at one or more corners of the
device, are located between the corners of the device, a
combination thereof, or form a continuous surface about a perimeter
of the device.
20. The packaged device of claim 19, further comprising an
electrostatic discharge layer interposed between the cured molding
compound and the device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent
application Ser. No. 15/840,900, filed on Dec. 13, 2017, which will
issue on Feb. 19, 2019 as U.S. Pat. No. 10,211,072, which claims
benefit of U.S. Provisional Patent Application Ser. No. 62/524,298,
filed on Jun. 23, 2017, each of which is herein incorporated by
reference in its entirety.
BACKGROUND
Field
[0002] Embodiments described herein generally relate to the field
of semiconductor device manufacturing, and more specifically, to
methods of packaging semiconductor devices.
Description of the Related Art
[0003] As circuit densities increase and device sizes decrease for
next generation semiconductor devices, providing the external
connections, i.e., wiring, to these devices requires advanced
packaging technologies. One such advanced packaging technology is
wafer level packaging.
[0004] Wafer level packaging streamlines the manufacturing and
packaging processes of semiconductor devices by integrating device
manufacturing, package assembly (packaging), electrical testing,
and reliability testing (burn-in) at the wafer level, where forming
of the top and bottom layers of the packaging, creating the I/O
connections, and testing the packaged device are all performed
before the devices are singulated into individual packaged
components. The advantages of wafer level packaging include reduced
overall manufacturing costs of the resulting device, reduced
package size, and improved electrical and thermal performance.
However, typical wafer level packaging schemes limit the number of
I/O connections that can be made from the semiconductor device to
the number of I/O terminals that can be spread over the surface of
the die. Fan-out wafer level packaging retains the advantages of
wafer level packaging while increasing the area available for I/O
terminals by redistributing the I/O terminals to areas exterior of
the surface of the die, using one or more redistribution
layers.
[0005] Fan-out wafer level packaging processes require that the
surface area of the I/O terminal redistribution layer for each
individual die be larger than the surface area of the individual
die itself. However, because it is desirable to maximize the number
of devices (dies) on a wafer in order to minimize costs during
manufacturing of the device, the spaces between individual devices
(dice lines) are usually only large enough to accommodate the width
of the dicing saw used to dice the wafer into its individual dies.
One method of creating the desired additional surface area external
of the die surface is to form a new wafer with dies redistributed
in a spaced apart pattern, known as a reconstituted substrate.
[0006] Typically, to form a reconstituted substrate, a wafer is
singulated into individual die which are then positioned on a
molding plate (carrier substrate) spaced apart from one another and
temporarily secured thereto by an adhesion layer. A molding
compound is dispensed onto the carrier substrate, and the dies
secured thereto, and subsequently cured, which embeds the spaced
apart dies in the molding compound to form the reconstituted
substrate. The terminal sides of the dies are then exposed by
removing the adhesion layer, and redistribution layers, having
interconnects disposed therein, are subsequently formed on the
reconstituted substrate, to redistribute a portion, or all, of the
device's I/O terminals to areas exterior of the surface of the die,
which increases the area available for I/O connections and thus the
number of possible I/O terminals.
[0007] Process defects associated with forming the reconstituted
substrate, such as undesirable repositioning of the dies within the
reconstituted substrate from their original placement location on
the adhesion layer, also known as die shift, cause misalignment
between the via interconnects in the subsequently formed
redistribution layer and the electrical contacts on the dies.
Accordingly, there is a need in the art for improved methods of
forming reconstituted substrates for fan-out wafer level packaging
schemes.
SUMMARY
[0008] Embodiments herein generally relate to device packaging
processes, and in particular, relate to methods of forming a
reconstituted substrate in a fan-out wafer level packaging
process.
[0009] In one embodiment, a method of forming a reconstituted
substrate is provided. The method includes positioning a plurality
of devices on a carrier substrate. Herein, the carrier substrate
comprises a structural base and an adhesion layer disposed on a
major surface thereof, where the active surfaces of the plurality
of singular devices are temporarily secured to the structural base
by the adhesion layer. The method further includes depositing a
device immobilization layer onto the plurality of singular devices
and onto at least a portion of the carrier substrate adjacent
thereto and extending laterally outward therefrom, wherein
depositing the device immobilization layer comprises a HWCVD
process, a PECVD process, a controlled dispense process, a spray
process, an additive manufacturing process, or a combination
thereof.
[0010] In another embodiment, another method of forming a
reconstituted substrate is provided. The method includes
positioning a plurality of devices on a carrier substrate. Herein,
the carrier substrate comprises a structural base and an adhesion
layer disposed on a major surface thereof, where the active
surfaces of the plurality of singular devices are temporarily
secured to the structural base by the adhesion layer. The method
further includes dispensing a plurality of droplets of a precursor
composition onto the carrier substrate at locations adjacent to
each of the plurality of devices, and at least partially curing
each of the plurality of dispensed droplets to form a plurality of
device immobilization beads.
[0011] In another embodiment, a reconstituted substrate is
provided. The reconstituted substrate comprises a plurality of
devices disposed in a molding compound, wherein an immobilization
layer or a plurality of immobilization beads is interposed between
each of the plurality of devices and the molding compound, and
wherein the immobilization layer or the plurality of immobilization
beads comprises parylene, urethane acrylate, epoxy acrylate,
thermal and/or UV curable modifications thereof, or combinations
thereof. In some embodiments, the reconstituted substrate further
comprises a polymer layer disposed on the plurality of devices, the
polymer layer having a plurality of metal interconnect structures
disposed therethrough. In some embodiments, the reconstituted
substrate further comprises an electrostatic discharge layer
interposed between the mold layer and the device. In some
embodiments, the immobilization layer has a thickness between about
0.5 .mu.m and 100 .mu.m. In some embodiments, the polymer layer
comprises polyimide.
[0012] In another embodiment, a packaged device is provided. The
packaged device comprises a first layer including a mold layer, a
device disposed in the mold layer, an second layer interposed
between at least a portion of the mold layer and at least a portion
of the device, and a first surface defined by an active surface of
the device and a surface or surfaces of the second layer. The
packaged device further comprises one or more redistribution layers
disposed on the first surface, each redistribution layer comprising
at least a dielectric layer and a plurality of interconnect
structures disposed therethrough. In some embodiments, the second
layer comprises parylene, urethane acrylate, epoxy acrylate,
modifications thereof (e.g. thermal and/or UV curable), or
combinations thereof. In some embodiments, the second layer has a
thickness of between about 0.5 .mu.m and about 100 .mu.m. In some
embodiments, the mold layer comprises an epoxy. In some
embodiments, the dielectric layer comprises a polyimide. In some
embodiments, the packaged device further comprises a conductive
layer interposed between the mold layer and the device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] So that the manner in which the above recited features of
the present disclosure can be understood in detail, a more
particular description of the disclosure, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this disclosure and are therefore not to be considered limiting of
its scope, for the disclosure may admit to other equally effective
embodiments.
[0014] FIG. 1A is a schematic cross-sectional view of an example
processing chamber, herein a hot-wire chemical vapor deposition
(HWCVD) chamber, used to practice some of methods described herein,
according to one embodiment.
[0015] FIG. 1B is a flowchart illustrating a method for forming a
reconstituted substrate, according to one embodiment.
[0016] FIGS. 2A-2E illustrate the formation of a reconstituted
substrate, according to the method of FIG. 1B.
[0017] FIG. 2F is a schematic plan view of an electrostatic
discharge layer, formed according to further embodiments of FIG.
1B.
[0018] FIGS. 2G-2H illustrate the formation or more redistribution
layers on the reconstituted substrate, according to further
embodiments of FIG. 1B.
[0019] FIG. 2I is a schematic cross-sectional view of a singulated
packaged device, formed according to further embodiments of FIG.
1B.
[0020] FIG. 3A is a schematic cross-sectional view of an example
additive manufacturing system used to practice the method of FIG. 4
according to one embodiment.
[0021] FIG. 3B is a close up cross-sectional view of a portion of
the carrier substrate shown in FIG. 3A.
[0022] FIG. 4 is a flow diagram illustrating a method of forming a
reconstituted substrate using the additive manufacturing system
described in FIG. 3A.
[0023] FIG. 5A is a schematic plan view of a device disposed on a
carrier substrate, according to one embodiment.
[0024] FIG. 5B is a side view of the device shown in FIG. 5B.
[0025] FIG. 5C is a schematic plan view of a device disposed on a
carrier substrate, according to one embodiment.
[0026] FIG. 5D is a side view of the device 204 shown in FIG.
5C.
[0027] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. It is contemplated that elements
disclosed in one embodiment may be beneficially utilized on other
embodiments without specific recitation.
DETAILED DESCRIPTION
[0028] Embodiments of the present disclosure generally describe
methods for minimizing the occurrence and extent of die shift
during the formation of a reconstituted substrate in fan-out wafer
level packaging processes.
[0029] Die shift is a process defect that occurs when a die
(device) moves from its intended position within a reconstituted
substrate during the formation thereof. Generally, the methods
disclosed herein include depositing a device immobilization layer
and/or a plurality of device immobilization beads over and/or
adjacent to a plurality of singulated dies (individual dies), and
the carrier substrate they are positioned on, before forming a
reconstituted substrate with an epoxy molding compound. The device
immobilization layer and/or the plurality of device immobilization
beads immobilize the plurality of singular devices and prevent them
from shifting on the carrier substrate during the molding
process.
[0030] Typically, some tolerance in alignment between the
interconnects in the redistribution layers and the device contact
pads in a fan-out wafer level packaging scheme must be built into
the manufacturing process to account for die shift. For example,
die shift can cause a die to deviate from its intended position in
a reconstituted substrate by 20 .mu.m to 140 .mu.m or more which
causes misalignment between via interconnects in a subsequently
formed redistribution layer and the contact sites on the die. One
contributing factor to die shift is the drag force the molding
compound exerts on the die as the molding compound is dispensed
onto the molding plate (carrier) and/or into a mold, such as a
compression mold. Additional factors contributing to die shift are
deformation of the molding compound during curing, warping of the
reconstituted substrate, and thermal expansion/contraction of the
molding compound and/or reconstituted substrate. By immobilizing
the plurality of singular devices on a carrier substrate using the
methods described herein, die shift is eliminated or substantially
reduced. Eliminating or substantially reducing die shift desirably
enables precise alignment of interconnect layers and scaling of
via/pitch dimensions which desirably allows for a reduction in the
final package size of a device.
[0031] FIG. 1A is a schematic cross-sectional view of an example
processing chamber, herein a hot-wire chemical vapor deposition
(HWCVD) chamber, used to practice some of methods described herein,
according to one embodiment.
[0032] The processing chamber 100 includes a chamber lid 102, one
or more sidewalls 104, and a chamber bottom 106, which define a
processing volume 108. The processing volume 108 is in fluid
communication with a vacuum source 116, such as one or more
dedicated vacuum pumps, through a vacuum outlet 118, which
maintains the processing volume 108 at sub-atmospheric conditions
and evacuates processing gases, and other gases, therefrom. A
carrier substrate support 120, disposed on a support shaft 132
sealingly extending through the chamber bottom 106, is disposed in
the processing volume 108 and a carrier substrate 210 is
transferred thereto and therefrom through an opening 124 formed
through the sidewall 104, which is sealed with a door or a valve
(not shown) during the deposition process. Typically, the carrier
substrate 210 is positioned on, and removed from, the carrier
substrate support 120 using a conventional lift pin system (not
shown). In some embodiments, the carrier substrate support 120 is
configured to heat, cool, and/or to maintain the carrier substrate
210 at a desired processing temperature using a resistive heater
126 embedded in and or disposed on the carrier substrate support
120 and/or cooling conduits 130 disposed in the carrier substrate
support 120. Typically the resistive heater 126 is coupled to a DC
power supply which provides current thereto and the cooling
conduits 130 are fluidly coupled to a cooling source (not shown),
such as a water or refrigerant source.
[0033] The processing chamber 100 further includes a plurality of
heating elements, herein a plurality of wires 128, disposed in the
processing volume 108 between the carrier substrate support 120,
and the carrier substrate 210 disposed thereon, and the chamber lid
102. The plurality of wires 128 are formed of a conductive
material, such as a steel alloy, and are electrically coupled to a
power supply (not shown). Herein, the processing volume 108 is
fluidly coupled to one or more gas supplies, such as gas supply
110, which provides processing gases to the processing volume 108
through one or more gas inlets, such as gas inlet 112 disposed
through a sidewall 104 at a location between a horizontal plane of
the plurality of wires 128 and the chamber lid 102. In other
embodiments, the gas inlet 112 is disposed through the chamber lid
102. In some embodiments, the processing chamber 100 further
includes a gas distributor (not shown), such as a showerhead,
disposed between the gas inlet 112 and the carrier substrate
support 120 and the carrier substrate 210 disposed thereon. In
embodiments herein, the processing gases include one or more
monomers and one or more initiator gases. During the HWCVD
deposition process the plurality of wires 128 are resistively
heated by electrical current flowing therethrough to a desired
temperature sufficient to catalytically dissociate the initiator
gases into their reactive species, e.g. radicals. The monomer
gas(es), absorbed onto a surface of the carrier substrate 210,
react with the dissociated reactive species of the initiator
gas(es) to deposit and/or form a polymer layer, herein an
immobilization layer 206, on the surface of the carrier substrate
210. Typically, a pressure in the processing volume 108 is
maintained at less than about 1 Torr, such as less than about 700
mTorr, such as between about 400 mTorr and about 1 Torr, or between
about 400 mTorr and about 700 mTorr.
[0034] FIG. 1B is a flowchart illustrating a method 150 for forming
a reconstituted substrate, according to one embodiment. FIGS. 2A-2E
illustrate the formation of a reconstituted substrate 212,
according to the method of FIG. 1B.
[0035] The method 150 begins at activity 155 with the positioning
of a plurality of devices, i.e., individual singular devices, on a
carrier substrate. A carrier substrate 210 is illustrated in FIG.
2A and it includes a structural base 200 having an adhesion layer
202 disposed on a major surface thereof. Herein, the structural
base 200 is a rigid substrate, such as a silicon wafer or a metal
plate. In other embodiments, the structural base 200 is a
rectangular panel made from a material having sufficient rigidity
to act as a mold plate, such as glass or a rigid polymer. In some
embodiments, the structural base 200 is made from glass or a rigid
polymer. Herein, the adhesion layer 202 is a double sided tape, a
temporary adhesive bonding film, a thermally releasable adhesive, a
photo-releasable adhesive, or any suitable adhesive layer for
temporarily securing the active surfaces of a plurality of devices
204 to the structural base 200. Herein, each of the plurality of
devices 204 has a thickness T(1) of between about 50 .mu.m and
about 800 .mu.m, such as between about 50 .mu.m and about 760
.mu.m, between about 50 .mu.m and about 400 .mu.m, or between about
50 .mu.m and about 300 .mu.m, such as between about 100 .mu.m and
about 300 .mu.m. Typically, each of the plurality of devices 204
are spaced apart from one another by a distance X so that a portion
of the structural base 200 associated with each device 204 has a
redistribution surface area that is greater than the surface area
of the device 204. The size of the redistribution surface
determines the surface area available for the formation of
redistribution layers on the to be formed reconstituted substrate.
The method 150 continues at activity 160 with depositing an
immobilization layer 206 over the plurality of devices 204 and the
adhesion layer 202, as shown in FIG. 2B. Herein, the immobilization
layer 206 is a polymer, such as parylene, urethane acrylate, epoxy
acrylate, modifications thereof, or combinations thereof, deposited
using a chemical vapor deposition (CVD) process, a hot wire CVD
process, a plasma enhanced CVD process (PECVD), or a controlled
dispense and/or spray process. In some embodiments, the
immobilization layer 206 is formed by depositing a UV curable
polymer precursor (using a controlled dispense and/or spray
process) over the plurality of devices 204 and the carrier
substrate 210 and exposing the deposited UV curable polymer
precursor, or portions thereof, to UV radiation from a UV radiation
source.
[0036] In one embodiment, the immobilization layer 206 is deposited
and/or formed using a HWCVD process in a HWCVD processing chamber,
such as the processing chamber 100 described in FIG. 1A. Typically,
the HWCVD process comprises flowing a processing gas comprising one
or more monomers and one or more initiators into the processing
volume of a processing chamber. The one or more monomers are
absorbed onto surfaces of the carrier substrate 210 and the
plurality of devices 204 disposed thereon. The one or more
initiators are dissociated into their reactive species by a
plurality of heated wires maintained at a temperature less than
about 600.degree. C., such as less than about 450.degree. C., for
example between about 100.degree. C. and about 450.degree. C. The
absorbed monomers react with the dissociated reactive species of
the initiator precursor to deposit or form the immobilization layer
206 over the carrier substrate 210 and the plurality of devices 204
disposed thereon. Immobilization layers 206 deposited using the
HWCVD methods described herein comprise the polymerized reaction
product of the one or more monomer gases and the dissociated
reactive species of one or more initiator precursors.
[0037] Monomer gases herein include ethyleneglycol diacrylate,
t-butylacrylate, N,N-dimethylacrylamide, vinylimidazole,
1-3-diethynylbenzene, 4-vinyl pyridine, poly vinyl pyridine, poly
4-vinyl pyridine, polyphenylacetylene, N,
N-dimethylaminoethylmethacrylate, divinylbenzene, poly
divinylbenzene, glycidyl methacrylate, poly thiophene,
ethyleneglycol dimethacrylate, tetrafluoroethylene,
dimethylaminomethylstyrene, perfluoroalkyl ethylmethacrylate,
trivinyltrimethoxy-cyclotrisiloxane, furfuryl methacrylate,
cyclohexyl methacrylate-co-ethylene glycol dimethacrylate,
pentafluorophenyl methacrylate-co-ethylene glycol diacrylate,
2-hydroxyethyl methacrylate, methacrylic acid,
3,4-ethylenedioxythiophene, and combinations thereof. In some
embodiments, the monomer gas further include a cross-linker source
gas to facilitate the cross-linking of the to be formed
immobilization layer 206. Cross-linker source gases here include
2-ethyl-2(hydroxymethyl)propane-trimethyacrylate (TRIM), acrylic
acid, methacrylic acid, trifluoro-methacrylic acid,
2-vinylpyridine, 4-vinylpyridine, 3(5)-vinylpyridine,
p-methylbenzoic acid, itaconic acid, 1-vinylimidazole, ethylene
glycol dimethacrylate, and combinations thereof.
[0038] Initiator precursors herein include, hydrogen peroxide,
alkyl peroxides, aryl peroxides, hydroperoxides, halogens, azo
compounds, and combinations thereof. In some embodiments, the
initiator source gas is selected from the group including
perfluorooctane sulfonyl fluoride (PFOS),
perfluorobutane-1-sulfonyl fluoride (PFBS), triethylamine (TEA),
tert-butyl peroxide (TBPO), 2,2'-azobis (2-methylpropane),
tert-amyl peroxide (TAPO), di-tert-amyl peroxide, antimony
pentachloride and benzophenone, and combinations thereof.
Typically, a ratio of initiator precursor to monomer gas is between
about 1:10 and about 1:1.
[0039] The polymerized reaction products herein include
poly(glycidyl methacrylate-co-divinylbenzene), poly(glycidyl
methacrylate-co-methacrylamide), poly(ethyleneglycol diacrylate),
poly(t-butylacrylate), poly N,N-dimethylacrylamide,
poly(vinylimidazole), poly(1-3-diethynylbenzene),
poly(phenylacetylene), poly(N,N-dimethylaminoethylmethacrylate)
(p(DMAM), poly (divinylbenzene), poly(glycidyl methacrylate)
(p(GMA)), poly (ethyleneglycol dimethacrylate), poly
(tetrafluoroethylene), poly(tetrafluoroethylene) (PTFE),
poly(dimethylaminomethylstyrene) (p(DMAMS), poly(thiophene),
poly(vinylpyridine), poly(perfluoroalkyl ethylmethacrylate),
poly(trivinyltrimethoxy-cyclotrisiloxane), poly(furfuryl
methacrylate), poly(cyclohexyl methacrylate-co-ethylene glycol
dimethacrylate), poly(pentafluorophenyl methacrylate-co-ethylene
glycol diacrylate), poly(2-hydroxyethyl methacrylate-co-ethylene
glycol diacrylate), poly(methacrylic acid-co-ethylene glycol
dimethacrylate), poly(3,4-ethylenedioxythiophene), and combinations
thereof.
[0040] In one embodiment, the immobilization layer 206 comprises
HWCVD deposited poly(glycidyl methacrylate) (p(GMA)) having a
thickness T(2) of more than about 1 .mu.m, such as between about 1
.mu.m and about 20 .mu.m, or more than about 8 .mu.m for a device
204 having a thickness T(1) of more than about 700 .mu.m and less
than about 8 .mu.m for a singulated die having a thickness T(1) of
less than about 700 .mu.m.
[0041] In some embodiments, the processing gas further includes a
carrier gas or a diluent gas, such as one or more inert gases, for
example helium (He), neon (Ne), argon (Ar), or combinations
thereof. In some embodiments, the one or more monomer gases and the
one or more initiator precursor gases are provided separately to
the processing volume of the processing chamber and allowed to mix
therein.
[0042] In some embodiments, the immobilization layer 206 forms a
continuous closed surface over the plurality of devices 204 and the
adhesion layer 202 exposed therebetween. Herein, the immobilization
layer 206 has a thickness of between about 0.5 .mu.m and 100 .mu.m,
such as between about 0.5 .mu.m and about 50 .mu.m, between about
0.5 .mu.m and 20 .mu.m, between about 0.5 .mu.m and about 10 .mu.m,
or between about 0.5 .mu.m and 5 .mu.m. In other embodiments, the
immobilization layer 206 has a thickness of more than about 100
.mu.m or less than about 0.5 .mu.m.
[0043] In other embodiments, the immobilization layer 206 forms a
discontinuous surface comprising a plurality of immobilization
layer regions, herein immobilization patches 207 (shown in phantom
in FIG. 2F), each disposed over a respective device 204 and
portions of the respective adhesion layer 202 adjacent thereto. In
some embodiments, the discontinuous surface of the immobilization
layer 206 is formed using a physical mask (i.e. a shadow mask)
during the deposition thereof, by a subsequent
photolithography/etch process, or by any other suitable means. In
some embodiments, the discontinuous surface of the immobilization
layer 206 is formed by selectively curing portions of the UV
curable polymer precursor to form the plurality of immobilization
layer regions and removing the uncured polymer precursor from
surfaces of the structural base 200 and/or portions of the adhesion
layer 202.
[0044] In some other embodiments, the immobilization layer 206
forms a continuous surface over the plurality of devices 204 and
over portions of the adhesion layer 202 exposed therebetween but
has openings (not shown) in the continuous surface between the
portions of the adhesion layer 202 covered by the immobilization
layer 206.
[0045] In some embodiments, the method 150 continues at activity
165 with dispensing a molding compound, such as an epoxy, to form a
mold layer 208 over the immobilization layer 206 as shown in FIG.
2C. Herein, the molding compound is dispensed using a spin
application wherein the molding compound is distributed over the
immobilization layer 206 and underlying carrier substrate 210 by
spinning the carrier substrate 210 while the molding compound is
dispensed thereover and/or thereon. In other embodiments the
molding compound is applied to the carrier substrate 210 and the
plurality of devices 204 disposed thereon by any conventional
molding process, such as pressure/compression molding, injection
molding, film assisted molding, or combinations thereof.
[0046] The method 150 continues at activity 175 with curing the
molding compound by exposing the molding compound to a UV source
209 as shown in FIG. 2D, by heating the molding compound, by
applying curing agents, by vacuum curing, or by a combination
thereof, to form a reconstituted substrate 212, as shown in FIG.
2E. In some embodiments the reconstituted substrate 212 is
planarized using a back grind process.
[0047] The method 150 continues at activity 180 with debonding the
reconstituted substrate 212 from the adhesion layer 202 of the
carrier substrate 210. In some embodiments, the method 150 further
includes forming an electrostatic discharge layer 205 on the
carrier substrate 210 and the plurality of devices 204 disposed
thereon before or after depositing the immobilization layer 206
thereover, as shown in FIG. 2F.
[0048] FIG. 2F is a schematic plan view of a carrier substrate,
such as the carrier substrate 210 described in FIG. 2A, having a
plurality of devices 204 disposed thereon, and further having an
electrostatic discharge layer 205 disposed over the plurality of
devices 204 and the exposed regions of the carrier substrate 210,
according to one embodiment. Herein, the electrostatic discharge
layer 205 is formed of a conductive polymer, a metal, or a plastic
with electrically conducting particles disposed therein. The
electrostatic discharge layer 205 is typically formed by printing a
conductive polymer or conductive ink, vapor deposition, such as
sputtering or evaporative deposition, or by placing a metal mesh
netting or gauze like fabric of conductive material on the surface
of the carrier substrate 210 and the plurality of devices 204
disposed thereon. Herein, the electrostatic discharge layer 205
comprises a plurality of parallel columns 205a and a plurality of
parallel rows 205b that are perpendicular to the plurality of
parallel columns 205a. During the formation of the reconstituted
substrate and the subsequent formation of redistribution layers
thereon, the electrostatic discharge layer 205 is used to dissipate
and/or prevent electrostatic charging of the carrier substrate
and/or the plurality of devices 204 disposed thereon.
[0049] In some embodiments, the method 150 further includes forming
one or more redistribution layers 214 on the reconstituted
substrate 212, as described in FIGS. 2G-2H.
[0050] FIG. 2G shows a reconstituted substrate 212 with one or more
redistribution layers 214 disposed thereon. Herein, the
reconstituted substrate 212 includes an electrostatic discharge
layer 205 interposed between the immobilization layer 206 and the
plurality of devices 204 and interposed between the immobilization
layer 206 and the one or more redistribution layers 214 in regions
between the devices 204. Typically, the electrostatic discharge
layer 205 has a thickness T(3) of less than about 100 .mu.m, such
as between about 20 .mu.m and about 50 .mu.m. In some embodiments,
the electrostatic discharge layer 205 is a metal layer having
thickness T(3) of less than about 20 .mu.m, such as between about
0.1 .mu.m and about 2 .mu.m. Each of the one or more redistribution
layers 214 comprises a dielectric layer 217, such as an oxide
layer, a nitride layer, or a polymer layer, for example a polyimide
layer, having a plurality of metal interconnect structures 215
disposed therethrough. Herein, the metal interconnect structures
215 include wire interconnects and/or via interconnects that alone
or in combination enable electrical coupling of bond pads 225 of
the device 204 to circuits external to the device 204 and the
redistribution layers 214. The reconstituted substrate 212 includes
the plurality of devices 204 embedded in the cured mold layer 208
with the immobilization layer interposed between each of the
plurality of devices 204 and the cured mold layer 208. Herein, the
immobilization layer 206 forms a continuous layer over the cured
mold layer 208 of the reconstituted substrate 212. In other
embodiments, the immobilization layer 206 comprises a discontinuous
layer comprising a plurality of immobilization patches 207 (shown
in phantom in FIG. 2F) disposed between portions of the cured mold
layer 208 and portions of the redistribution layer 214 in locations
adjacent to each of the plurality of devices 204 and extending
laterally outward therefrom.
[0051] In some embodiments, the method 150 further comprises
electrically coupling a plurality of solder balls 216 to the metal
interconnect structures 215 and singulating the reconstituted
substrate 212 and the layers and features formed thereon, into
singulated packaged devices 218 such as shown in FIGS. 2H-2I. FIG.
2H shows the reconstituted substrate 212 of FIG. 2E further
comprising an electrostatic discharge layer 205 and further
comprising the plurality of solder balls 216 electrically coupled
to the plurality of metal interconnect structures 215 of the
redistribution layer 214. FIG. 2I shows a singulated packaged
device 218 where a first layer of the packaged device, herein a
portion of the reconstituted substrate 212, includes the mold layer
208, the immobilization layer 206 (second layer), the electrostatic
discharge layer 205 (third layer), and the device 204. Herein, an
active surface of the device 204, having bond pads 225 disposed
therein, a surface of the electrostatic discharge layer 205 and/or
a surface of the immobilization layer 206 disposed between surfaces
of the electrostatic discharge layer 205 define a planer surface
230, the redistribution layer 214 disposed thereon. In other
embodiments, an active surface of the device 204, having bond pads
225 disposed therein, and a surface of the immobilization layer 206
(second layer) define a planer surface 230, the redistribution
layer 214 disposed thereon. Herein, the redistribution layer 214 is
separated from the mold layer 208 by the electrostatic discharge
layer 205 (third layer) and/or the immobilization layer 206 (second
layer) and does not make contact therewith. In other embodiments,
at least portions of the redistribution layer 214 are separated
from the mold layer 208 by the electrostatic discharge layer 205
(third layer) and/or the immobilization layer 206 (second layer) in
regions adjacent to the device 204 and extending laterally outward
therefrom.
[0052] The method 150 described above immobilizes the device during
the molding process of forming the reconstituted substrate, which
prevents die shift and reduces process defects related to
misalignment of subsequently formed redistribution layers and the
contact pads of the device.
[0053] FIG. 3A is a schematic view of an example additive
manufacturing system 300 used to practice some of the methods
described herein, according to one embodiment. Herein the additive
manufacturing system 300 comprises a manufacturing support 301, one
or more dispense heads, such as dispense head 303, for dispensing
droplets 305 of a precursor composition 307, and an electromagnetic
radiation source, such as UV source 309. Typically, each of the one
or more dispense heads 303 further comprises one or more nozzles
311. The carrier substrate 210, and the plurality of devices 204
disposed thereon, are positioned on the manufacturing support 301
which moves independently of the dispense head 303 to enable
dispensing of the droplets 305 on selected locations on the carrier
substrate 210 and the plurality of devices 204.
[0054] Herein, the precursor composition 307 comprises a mixture of
one or more functional polymers, functional oligomers, functional
monomers, and/or reactive diluents that are at least monofunctional
and undergo polymerization when exposed to free radicals;
photoacids, Lewis acids, and/or electromagnetic radiation.
[0055] Examples of functional polymers herein include
multifunctional acrylates including di, tri, tetra, and higher
functionality acrylates, such as
1,3,5-triacryloylhexahydro-1,3,5-triazine or trimethylolpropane
triacrylate.
[0056] Examples of functional oligomers include monofunctional and
multifunctional oligomers, acrylate oligomers, such as aliphatic
urethane acrylate oligomers, aliphatic hexafunctional urethane
acrylate oligomers, diacrylate, aliphatic hexafunctional acrylate
oligomers, multifunctional urethane acrylate oligomers, aliphatic
urethane diacrylate oligomers, aliphatic urethane acrylate
oligomers, aliphatic polyester urethane diacrylate blends with
aliphatic diacrylate oligomers, or combinations thereof, for
example bisphenol-A ethoxylate diacrylate or polybutadiene
diacrylate. In one embodiment, the functional oligomer comprises
tetrafunctional acrylated polyester oligomer available from Allnex
Corp. of Alpharetta, Ga. as EB40.RTM. and the functional oligomer
comprises an aliphatic polyester based urethane diacrylate oligomer
available from Sartomer USA of Exton, Pa. as CN991.
[0057] Examples of monomers used in the precursor composition
include tetrahydrofurfuryl acrylate (e.g. SR285 from
Sartomer.RTM.), tetrahydrofurfuryl methacrylate, vinyl caprolactam,
isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl
acrylate, 2-phenoxyethyl methacrylate, 2-(2-ethoxyethoxy)ethyl
acrylate, isooctyl acrylate, isodecyl acrylate, isodecyl
methacrylate, lauryl acrylate, lauryl methacrylate, stearyl
acrylate, stearyl methacrylate, cyclic trimethylolpropane formal
acrylate, 2-[[(Butylamino) carbonyl]oxy]ethyl acrylate (e.g.
Genomer 1122 from RAHN USA Corporation), 3,3,5-trimethylcyclohexane
acrylate, or mono-functional methoxylated PEG (350) acrylate.
Multifunctional monomers include diacrylates or dimethacrylates of
diols and polyether diols, such as propoxylated neopentyl glycol
diacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol
dimethacrylate, 1,3-butylene glycol diacrylate, 1,3-butylene glycol
dimethacrylate 1,4-butanediol diacrylate, 1,4-butanediol
dimethacrylate, alkoxylated aliphatic diacrylate (e.g., SR9209A
from Sartomer.RTM.), diethylene glycol diacrylate, diethylene
glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene
glycol diacrylate, triethylene glycol dimethacrylate, alkoxylated
hexanediol diacrylates, or combinations thereof, for example SR562,
SR563, SR564 from Sartomer.RTM..
[0058] Examples of reactive diluents used in the precursor
composition include monoacrylate, 2-ethylhexyl acrylate, octyldecyl
acrylate, cyclic trimethylolpropane formal acrylate, caprolactone
acrylate, isobornyl acrylate (IBOA), or alkoxylated lauryl
methacrylate.
[0059] Examples of photoacids used in the precursor composition
include onium salts such as Omnicat 250, Omnicat 440, and Omnicat
550, manufactured by manufactured by IGM Resins USA Inc. of
Charlotte N.C. and compositional equivalents thereof,
triphenylsulfonium triflate, and triarylsulfonium salt type photo
acid generators such as CPI-210S available from San-Apro Ltd. of
Tokyo, Japan, and compositional equivalents thereof.
[0060] In some embodiments, the precursor composition 307 further
comprises one or more photoinitiators. Photoinitiators used herein
include polymeric photoinitiators and/or oligomer photoinitiators,
such as benzoin ethers, benzyl ketals, acetyl phenones, alkyl
phenones, phosphine oxides, benzophenone compounds and thioxanthone
compounds that include an amine synergist, combinations thereof,
and equivalents thereof. For example, in some embodiments
photoinitiators include Irgacure.RTM. products manufactured by BASF
of Ludwigshafen, Germany, or equivalent compositions.
[0061] Typically, the precursor composition 307 is formulated to
have a viscosity between about 80 cP and about 110 cP at about
25.degree. C., between about 12 cP and about 30 cP at about
70.degree. C., or between 10 cP and about 40 cP for temperatures
between about 50.degree. C. and about 150.degree. C. so that the
precursor compositions 307 may be effectively dispensed through the
nozzles 311 of the one or more dispense heads 303.
[0062] Herein, each of the droplets 305 is at least partially cured
using electromagnetic radiation, such as the UV radiation 315
provided by the UV source 309, before the droplet 305 reaches its
equilibrium size as described further in FIG. 3B.
[0063] FIG. 3B is a close up cross-sectional view of a portion of
the carrier substrate 210 shown in FIG. 3A. Herein, each of the
plurality of devices 204 includes a horizontal surface 204a and a
one or more vertical surfaces 204b substantially normal to the
horizontal surface 204a and substantially normal to the carrier
substrate 210 including the adhesion layer 202 thereof. An
immobilization bead 305a, of a plurality of immobilization beads
305a (shown in FIG. 5A) formed of an at least partially cured
droplet 305 of the precursor composition 307 secures (tacks) the
device 204 to the carrier substrate 210 to prevent lateral movement
of the device 204 relative to the surface of the carrier substrate
210, or in other words to prevent/and or substantially reduce die
shift during the formation of a reconstituted substrate.
[0064] Typically, an uncured dispensed droplet, such as the example
uncured dispensed droplet 305b, will spread to an equilibrium size
having an equilibrium contact angle .alpha. within a very short
period of time, such as less than about 1 second, from the moment
the droplet 305 first comes into contact with a surface of the
carrier substrate 210 and/or a surface of one of the plurality of
devices 204 disposed thereon. Therefore, herein, the droplets 305
are at least partially cured (fixed) by exposure thereof to UV
radiation 315 from the UV source 309 to form the immobilization
bead 305a having a fixed contact angle .theta. that is greater than
the equilibrium contact angle .alpha.. Herein, the fixed contact
angle .theta. of the immobilization bead 305a is desirably
controlled to a value of greater than about 50.degree., such as
greater than about 55.degree., greater than about 60.degree., or
greater than about 70.degree., or even greater than about
80.degree.. The immobilization bead 305a herein covers at least a
portion of the vertical surface 204b of the device 204 and a
portion of the carrier substrate 210, including the adhesion layer
202 thereof, adjacent to the device 204 and extending laterally
outward therefrom.
[0065] FIG. 4 is a flow diagram illustrating a method of forming a
reconstituted substrate using the additive manufacturing system 300
described in FIG. 3A.
[0066] The method 400 begins at activity 410 with the positioning
of a plurality of devices, i.e., individual singulated dies, on a
carrier substrate, such as the carrier substrate 210 illustrated in
FIG. 2A. In some embodiments, the method further includes forming
an electrostatic discharge layer, such as the electrostatic
discharge layer 205 described in FIG. 2F or other embodiments of
the electrostatic discharge layer 205 described herein, on the
carrier substrate 210 and the plurality of devices 204 disposed
thereon.
[0067] The method 400 continues at activity 420 with dispensing a
plurality of droplets of a precursor composition onto the carrier
substrate at a location adjacent to a vertical portion of a device
204 and at least partially curing each of the plurality of
dispensed droplets at activity 430 to form a plurality of
immobilization beads, as shown in FIGS. 5A-5B.
[0068] FIG. 5A is a schematic plan view of a device 204 disposed on
a carrier substrate 210, according to one embodiment. FIG. 5B is a
side view of the device 204 shown in FIG. 5A further showing (in
phantom) an electrostatic discharge layer 205 and the mold layer
208 disposed thereon. Herein, a plurality of immobilization beads
305a prevent lateral movement of the device 204 in relation to the
carrier substrate 210 during the formation of the mold layer 208
(as shown in FIGS. 2C-2E). Typically, the immobilization beads 305a
are located at the corners of the device 204, are located between
the corners of the device 204, or a combination thereof. Each of
the immobilization beads 305a covers at least a portion of the one
or more vertical surfaces 204b (shown in FIG. 3B) of the device 204
and at least a portion of the carrier substrate 210 adjacent to the
vertical surface 204b and extending laterally outward therefrom. In
some embodiments, an electrostatic discharge layer 205 (shown in
phantom in FIG. 5B), such as the electrostatic discharge layer 205
described in FIG. 2F, is interposed between each of the
immobilization beads 305a and the device 204 and/or the carrier
substrate 210. In some other embodiments, the electrostatic
discharge layer is interposed between portions of the
immobilization beads 305a and/or some of the immobilization beads
305a and the device 204 and/or the carrier substrate.
[0069] In other embodiments, the droplets 305 are dispensed to form
an immobilization patch over the device 204 and portions of the
carrier substrate 210 adjacent thereto and extending laterally
outward therefrom.
[0070] In some embodiments, a plurality of droplets 305 are
dispensed and at least partially cured to form a continuous
immobilization bead layer 305d about the perimeter of the device
204 as shown in FIGS. 5C and 5D. FIG. 5C is a schematic plan view
of a device 204 disposed on a carrier substrate 210, according to
one embodiment. FIG. 5D is a side view of the device 204 shown in
FIG. 5C further showing (in phantom) the electrostatic discharge
layer 205 and the mold layer 208 disposed thereon. Herein, the
immobilization bead layer 305d forms a continuous surface about the
perimeter of the device 204 and prevents lateral movement of the
device 204 in relation to the carrier substrate 210 during the
formation of the mold layer 208 (as shown in FIGS. 2C-2E).
[0071] In some embodiments, the method 400 further includes UV
curing the immobilization beads 305a, and or immobilization bead
layers 305d in a UV furnace for between about 5 minutes and about 2
hours, such as between about 5 minutes and about 90 minutes, or
about 1 hour, at a curing temperature between about 50.degree. C.
and about 200.degree. C., such as between about 50.degree. C. and
about 150.degree. C., or less than about 150.degree. C.
[0072] The method 400 continues at activity 440 with dispensing a
molding compound over the carrier substrate, the plurality of
singular devices, and the immobilization layer thereon, at activity
450 with curing the molding compound to form a reconstituted
substrate 512a (shown in FIG. 5C) or 512b (shown in FIG. 5D, and
activity 460 with debonding the reconstituted substrate from the
carrier, which correspond to activities 165, 175, and 180
respectively of method 150 described in FIG. 1B.
[0073] In some embodiments, the method 400 further includes forming
one or more redistribution layers on the reconstituted substrate
212, as described above in FIG. 2G.
[0074] The method 400 described above immobilizes the device during
the molding process of forming the reconstituted substrate, which
prevents die shift and reduces process defects related to
misalignment of subsequently formed redistribution layers and the
contact pads of the device.
[0075] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the disclosure
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *