U.S. patent application number 16/366388 was filed with the patent office on 2019-07-18 for method for the production of an electronic module having an electronic component embedded therein.
This patent application is currently assigned to AT&S Austria Technologie & Systemtechnik Aktiengesellschaft. The applicant listed for this patent is AT&S Austria Technologie & Systemtechnik Aktiengesellschaft. Invention is credited to Gregor Langer, Johannes Stahr.
Application Number | 20190221718 16/366388 |
Document ID | / |
Family ID | 53175312 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190221718 |
Kind Code |
A1 |
Langer; Gregor ; et
al. |
July 18, 2019 |
Method for the Production of an Electronic Module Having an
Electronic Component Embedded Therein
Abstract
An electronic module and method for the production of the
electronic module in accordance with some embodiments of the
invention are disclosed. The electronic module includes at least
one electronic component affixed to a conductive layer by means of
sticky electrically insulating layer, where the electronic
component is embedded in a transparent foil. The electronic module
is produces by providing an electrically conductive layer. At least
one electronic component is affixed to the electrically conductive
layer by means of a sticky electrically insulating layer and
embedded in a transparent foil. The at least one electronic
component is electronically contacted with the conductive
layer.
Inventors: |
Langer; Gregor; (Wolfnitz,
AT) ; Stahr; Johannes; (St. Lorenzen, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AT&S Austria Technologie & Systemtechnik
Aktiengesellschaft |
Leoben |
|
AT |
|
|
Assignee: |
AT&S Austria Technologie &
Systemtechnik Aktiengesellschaft
Leoben
AT
|
Family ID: |
53175312 |
Appl. No.: |
16/366388 |
Filed: |
March 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15147673 |
May 5, 2016 |
10283680 |
|
|
16366388 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 2224/04105
20130101; H01L 33/60 20130101; H01L 2933/0066 20130101; H05K 1/188
20130101; H01L 2224/19 20130101; H05K 3/305 20130101; H05K 3/284
20130101; H01L 2933/0033 20130101; H01L 33/56 20130101; H01L 33/486
20130101; H01L 2933/0058 20130101; H01L 33/0095 20130101; H05K
2201/10106 20130101; H01L 33/62 20130101; H01L 2224/18 20130101;
H05K 2201/0108 20130101 |
International
Class: |
H01L 33/48 20060101
H01L033/48; H01L 33/00 20060101 H01L033/00; H05K 1/18 20060101
H05K001/18; H01L 33/62 20060101 H01L033/62 |
Foreign Application Data
Date |
Code |
Application Number |
May 8, 2015 |
EP |
15166915.7 |
Claims
1. An electronic module comprising at least one electronic
component affixed to a conductive layer by means of sticky
electrically insulating layer, the electronic component being
embedded in a transparent foil.
2. An electronic module according to claim 1, characterized in that
the electronic component is chosen from the group consisting of a
light-emitting diode (LED), a laser-diode, a photo-diode, a
photographic sensor, a photonic chip and a proximity sensor.
3. An electronic module according to claim 1, characterized in that
the electronic component is a flipchip-component.
4. An electronic module according claim 1, characterized in that a
light-reflecting layer is applied to the electrically conductive
layer.
5. An electronic module according to claim 1, characterized in that
the light-reflecting layer is formed by a material chosen from the
group consisting of solder resist and ceramic paste.
6. An electronic module according to claim 1, characterized in that
the light-reflecting layer is formed by a layer chosen from the
group consisting of a metal layer and an oxide layer.
7. An electronic module according to claim 1, characterized in that
the transparent foil is an ethylene-vinyl acetate-foil.
8. An electronic module according to claim 1, characterized in that
the transparent foil is covered with a protective layer in form of
a glass-plate.
9. An electronic module according to claim 1, characterized in that
the transparent foil is structured to relief-like
surface-structures.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present invention is a divisional of U.S. application
Ser. No. 15/147,673 , filed May 5, 2016, which application claims
priority to European Application No. 15166915.7, filed May 8, 2015,
the disclosures of which are incorporated herein by reference in
their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for the production
of an electronic module as well as the corresponding electronic
module.
BACKGROUND
[0003] It is an object of the present invention to provide a new
type of electronic module which can be used as a display, a
lighting installation or a camera.
SUMMARY OF THE INVENTION
[0004] To achieve this object the inventive method is characterized
by the following steps: [0005] a) providing an electrically
conductive layer [0006] b) affixing at least one electronic
component on the electrically conductive layer by means of a sticky
electrically insulating layer [0007] c) embedding the at least one
electronic component in a transparent foil [0008] d) electrically
contacting the at least one electronic component with the
conductive layer.
[0009] In the following, the invention will be described mostly
with reference to light-emitting components for the sake of
simplicity. It is, however, intended to encompass a large number of
electronic components. The terms "light-emitting component" and
"electronic component" will be used interchangeably within this
description. The electronic components to be used in the context of
the present invention will be mentioned below.
[0010] By the inventive steps for the production of an electronic
module it is possible to provide a large number of electronic
components, in particular light-emitting components on an
electrically conductive layer which light-emitting components when
properly contacted by the electrically conductive layer can be
controlled to emit light in any desired manner so that the
electronic module can serve as a cheap but effective lighting
installation or display for displaying any kind of image or
information. Also, it can receive information by light. The use of
sticky electrically insulating layer for affixing an electronic
component on the electrically conductive layer avoids short-cutting
of the electronic component by the underlying electrically
conductive layer and embedding the component in a transparent foil
protects the electronic component from chemical and mechanical
influences. While the present description is given with reference
to a single light-emitting component, it is clear to a person
skilled in the art that a large number of light-emitting components
will be arranged on an electrically conductive layer to form an
electronic module with the capability to serve as a lighting
installation, display, camera or the like.
[0011] Preferably, the electronic component is chosen from the
group comprised of a light-emitting diode (LED), a laser-diode, a
photo-diode and a photographic sensor. All these electronic
components profit from being embedded in the transparent foil.
[0012] According to a preferred embodiment, the light-emitting
component is a LED-flip-chip-component. A LED-flip-chip-component
is particularly suitable to be used in the inventive method since
LED technology allows for bright, distinct light points serving as
pixels on a display or lighting installation at a very low cost.
Flip-chip-components are electronic components having contact pads
on the opposite side of the light-emitting side of the component so
that when such a component is affixed on the electrically
conductive layer by means of an electrically insulating layer of
glue the contact pads of the component are oriented towards the
electrically conductive layer and can in a later process stage
easily be contacted with the electrically conductive layer.
[0013] As already mentioned, it is desirable within the context of
the present invention to arrange a large number of light-emitting
components on the electrically conductive layer and in particular
it is advantageous to bring those components close to one another
in order to provide for continuous lighting or a high resolution in
case the electronic module serves as a display for displaying
images or other information. To this end the invention preferably
is characterized in that the step of contacting the light-emitting
component comprises a step of laser-drilling the conductive layer
and the sticky electrically insulating layer, since laser-drilling
is a method that allows for high precision drilling of very small
holes which subsequently can be filled for example with copper by
copper plating procedures well known in the art of the production
of printed circuit boards.
[0014] In order to further increase light emission from the
electronic module, the inventive method preferably is characterized
in that prior to the step of affixing the light-emitting component
on the electrically conductive layer, a light-reflecting layer is
applied to the electrically conductive layer. That means that light
that is reflected to the electrically conductive layer for example
by reflection on the boundary layer of the transparent foil will be
reflected back again, so that the overall yield of light is
increased which is particularly useful for lighting
installations.
[0015] According to a preferred embodiment, the inventive method is
characterized in that the light-reflecting layer is formed by a
material chosen from the group consisting of solder resist and
ceramic paste. It is important that the solder resist will not
change color even when exposed to the light of the light-emitting
components over a very long period of time. The use of ceramic
paste in this context is particularly advantageous, since ceramic
paste will not change color over time.
[0016] Another possibility that is contemplated according to a
preferred embodiment of the present invention is characterized in
that the light-reflecting layer is formed by a layer chosen from
the group consisting of a metal layer and an oxide layer.
[0017] For the purposes of the present invention it is preferred
that the transparent foil is an ethylene-vinyl acetate-foil.
Ethylene-vinyl acetate (EVA) is highly transparent and flexible and
thus allows for the flexible and transparent embedding of the
light-emitting components, so that overall a flexible product is
obtained which can be mounted also on curved surfaces.
[0018] A preferred embodiment of the present invention is
characterized in that embedding the component comprises laminating
the transparent foil by means of a vacuum-lamination method at a
suction pressure of 1 bar to 5 bar at a temperature of 130.degree.
C. Under these conditions the transparent foil will readily adhere
to the electrically conductive layer snuggly surrounding the
components thereby embedding them and protecting them from
mechanical or chemical damage.
[0019] In order to protect the transparent foil during the various
process steps and in particular during the step of contacting the
light-emitting component with a conductive layer which as stated
above normally entails copper plating and also etching procedures,
the method according to the present invention preferably is
characterized in that the transparent foil is covered with a
protective layer chosen from the group consisting of a plastic
foil, a protective lacquer and a metal foil. A plastic foil, a
protective lacquer and a metal foil can be removed after possibly
damaging process steps leaving the transparent foil completely
unharmed.
[0020] According to an alternative embodiment of the present
invention the transparent foil is covered with a protective layer
in form of a glass-plate. The glass-plate serves for the same
purpose as the above plastic foils, protective lacquers and metal
foils. However, the glass-plate may stay in place even on the final
product protecting the transparent foil during the whole life time
of the electronic module. In this context it is also conceivable
that the glass-plate is thin enough to not impair the flexibility
of the electronic module of the present invention. For example, the
glass-plate preferably has a thickness of 50 .mu.m.
(.mu.m=micrometer).
[0021] When the protective layer is structured for engraving
relief-like surface-structures into the transparent foil, as it is
in conformity with a preferred embodiment of the present invention,
optical structures such as lenses and the like can be formed on the
outer surface of the transparent foil. In this case the protective
layer will, of course, have to be removed to yield the final
product.
[0022] In principle the protective layer can be applied to the
transparent foil in a separate production step. According to a
preferred embodiment it is, however, envisaged that the protective
layer is applied together with the transparent foil.
[0023] Alternative or additionally the transparent foil is
chemically roughened turning the transparent foil into a turbid
display for lighting installation purposes.
[0024] Preferably, the sticky electrically insulating layer is
chosen from the group comprised of a layer of glue and a sticky
tape.
[0025] The inventive electronic module comprises at least one
electronic component affixed to a conductive layer by means of
sticky electrically insulating layer, the light-emitting component
being embedded in a transparent foil. Thus a large number of
light-emitting components can be provided on an electrically
conductive layer which light-emitting components when properly
contacted by the electrically conductive layer can be controlled to
emit light in any desired manner so that the electronic module can
serve as a cheap but effective lighting installation, display,
camera or the like for displaying or receiving any kind of image or
information. The use of sticky electrically insulating layer for
affixing an electronic component on the electrically conductive
layer avoids short-cutting of the electronic component or
light-emitting component by the underlying electrically conductive
layer and embedding the component in a transparent foil protects
the light-emitting component from chemical and mechanical
influences. While the present description is given with reference
to a single electronic component, it is clear to a person skilled
in the art that a large number of light-emitting components will be
arranged on an electrically conductive layer to form an inventive
electronic module with the capability to serve as a lighting
installation, display, camera or the like.
[0026] Preferably, the electronic component is chosen from the
group comprised of a light-emitting diode (LED), a laser-diode, a
photo-diode and a photographic sensor. All these electronic
components profit from being embedded in the transparent foil.
[0027] A preferred embodiment of the present invention is
characterized in that the light-emitting component is a
LED-flipchip-component. A LED-flipchip-component is particularly
suitable to be used in the inventive electronic module since LED
technology allows for bright, distinct light points serving as
pixels on a display or lighting installation at a very low cost.
Flip-chip-components are electronic components having contact pads
on the opposite side of the light-emitting side of the component so
that when such a component is affixed on the electrically
conductive layer by means of an electrically insulating layer of
glue the contact pads of the component are oriented towards the
electrically conductive layer and can easily be contacted with the
electrically conductive layer.
[0028] According to a preferred embodiment the inventive electronic
module is characterized in that the light-reflecting layer is
formed by a material chosen from the group consisting of solder
resist and ceramic paste. It is important that the solder resist
will not change color even when exposed to the light of the
light-emitting components over a very long period of time. The use
of ceramic paste in this context is particularly advantageous,
since ceramic paste will not change color over time.
[0029] Another possibility that is contemplated according to a
preferred embodiment of the present invention is characterized in
that the light-reflecting layer is formed by a layer chosen from
the group consisting of a metal layer and an oxide layer.
[0030] For the purposes of the present invention it is preferred
that the transparent foil is an ethylene-vinyl acetate-foil.
Ethylene-vinyl acetate (EVA) is highly transparent and flexible and
thus allows for the flexible and transparent embedding of the
light-emitting components, so that overall a flexible product is
obtained which can be mounted also on curved surfaces.
[0031] According to an alternative embodiment of the present
invention the transparent foil is covered with a protective layer
in form of a glass-plate. The glass-plate may stay in place even on
the final product protecting the transparent foil during the whole
life time of the electronic module. In this context it is also
conceivable that the glass-plate is thin enough to not impair the
flexibility of the electronic module of the present invention. For
example, the glass-plate preferably has a thickness of 50
.mu.m.
[0032] When the transparent foil is structured to relief-like
surface-structures, as it is in conformity with a preferred
embodiment of the present invention, optical structures such as
lenses and the like can be formed on the outer surface of the
transparent foil.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will now be described with reference to the
accompanying drawings in which
[0034] FIGS. 1a)-1e) show inventive process steps to produce the
inventive electronic module
[0035] FIG. 2 shows a variant of the present invention, in which a
light-reflecting layer is applied to the electrically conductive
layer
[0036] FIG. 3 shows a variant of the present invention, in which
the transparent foil is structured to relief-like
surface-structures
[0037] FIG. 4 shows a protective layer applied to the inventive
electronic module of FIG. 2
[0038] FIGS. 5a)-5b) show process steps to structure the
transparent foil to relief-like surface-structures
[0039] FIG. 6 shows a variant of the invention in which the
light-emitting component is covered with a globe top and
[0040] FIG. 7 shows a variant of the invention in which the
light-emitting component is packaged.
DETAILED DESCRIPTION
[0041] In FIG. 1a), the conductive layer is denoted by reference
numeral 1. the electronic component, in this case a LED-chip is
denoted by reference numeral 2 and is affixed to the conductive
layer 1 by means of a sticky electrically insulating layer 3 of
glue completely electrically insulating the contact pads 4 of the
light-emitting component 2 from the conductive layer 1. In the next
process step depicted in FIG. 1b), the light-emitting component 2
is embedded in a transparent foil 5 for example by
vacuum-lamination at a suction pressure of 1 bar to 5 bar at a
temperature of 150.degree. C. for about 30 minutes. This ensures
that the transparent foil 5 completely surrounds the light-emitting
component 2 and fills all possible gaps and corners between the
light-emitting component 2 and the conductive layer 1 so that the
light-emitting component is snuggly embedded within the transparent
foil 5. Next, the so far continuous conductive layer 1 is subjected
to a laser-drilling procedure to drill holes to expose the contact
pads 4 of the light-emitting component 2. The contact pads 4 of the
light-emitting component 2, are arranged on the opposite side of
the light-emitting side of the component. This arrangement is known
to the person skilled in the art as a flip-chip configuration. The
laser-drilling procedure is adapted to also remove the electrically
insulating layer of glue 3 in the area of the contact pads 4 (FIG.
1c)). In FIG. 1d) a step of copper-plating is depicted which serves
to fill the holes drilled in the previous step with copper thereby
electrically connecting the contact pads 4 of the light-emitting
component 2 to the conductive layer 1. In the next step, shown in
FIG. 1e), the conductive layer 1 is suitably structured, for
example by photolithography to turn the continuous conductive layer
1 into a conductive layer 1 of conductive paths, wiring the
light-emitting component 2, to a power source and making to
controllable by a microcomputer which can be arranged on the
conductive layer 1 or which can be a self-contained module
connected to the electronic module of the present invention by a
suitable connector. For the sake of simplicity this is not shown in
the drawings. While the present invention is claimed and described
with regard to a single light-emitting component 1 it should be
noted that the inventive process can be carried out with a large
number of light-emitting components 2 arranged on the conductive
layer 1 and that a large number of light-emitting components 2 can
be embedded in the transparent foil 5 for example with the above
described vacuum-lamination procedure at a time.
[0042] In the variant of the present invention depicted in FIG. 2 a
light-reflecting layer 6 is applied to the conductive layer 1,
which serves to reflect light that is scattered from the boundary
layer 7 of the transparent foil 2 back again thereby increasing the
light-yield of the inventive product. The light-reflecting layer 6
can be white solder resist lacquer or a ceramic as in conformity
with a preferred embodiment of the present invention.
[0043] FIG. 3 shows a preferred embodiment in which the transparent
foil 5 is structured to relief-like structures schematically
depicted by the jagged outline of the transparent foil 5. The
relief-like structures alter the optical properties of the
transparent foil 5 and the inventive module and can be designed
accordingly.
[0044] In FIG. 4, the transparent foil 5 is covered with a
protective layer 8, which can take the form of a plastic foil, a
protective lacquer and a metal foil. The protective layer 8 can be
removed after possibly damaging process steps, for example copper
plating and etching procedures in photolithography leaving the
transparent foil 5 completely unharmed. According to the variant of
FIG. 5a), the protective layer 8 is structured for engraving
relief-like surface-structures into the transparent foil, which
structures are revealed upon removal of the protective layer 8
(FIG. 5b)). In this particular example, the relief-like structures
take the form of a lens 9 arranged above the light-emitting
component 2.
[0045] In the example of FIG. 6, the light-emitting component 2 is
covered by a so-called globe top 10, which serves to modulate the
wavelength of the light emitted by the light-emitting component 2.
As can be seen in this example, the globe top also can easily be
embedded in the transparent foil 5.
[0046] Alternatively, the light-emitting component 2 can be a
packaged LED-chip (FIG. 7).
[0047] Although the present invention has been described in certain
specific aspects, many additional modifications and variations
would be apparent to those skilled in the art. It is therefore to
be understood that the present invention may be practiced otherwise
than specifically described, including various changes in the
implementation such as utilizing encoders and decoders that support
features beyond those specified within a particular standard with
which they comply, without departing from the scope and spirit of
the present invention. Thus, embodiments of the present invention
should be considered in all respects as illustrative and not
restrictive.
* * * * *