U.S. patent application number 15/259266 was filed with the patent office on 2016-12-29 for led sub-mount and method for manufacturing light emitting device using the sub-mount.
The applicant listed for this patent is Lextar Electronics Corporation. Invention is credited to Der-Ling Hsia, Cheng-Ta Kuo, Chia-En Lee.
Application Number | 20160380173 15/259266 |
Document ID | / |
Family ID | 51350578 |
Filed Date | 2016-12-29 |
United States Patent
Application |
20160380173 |
Kind Code |
A1 |
Lee; Chia-En ; et
al. |
December 29, 2016 |
LED Sub-Mount and Method for Manufacturing Light Emitting Device
Using the Sub-Mount
Abstract
A light emitting device manufacturing method includes the
following steps. A sub-mount, which has a plurality of
electrical-conductive layers, is provided, and a surface between
every adjacent two of the electrical-conductive layers has an
adhesive-filling groove. An LED chip, which has a bottom substrate,
is mounted on the sub-mount by a flip-chip way, and two electrodes
of the LED chip are in contact with adjacent two of the
electrical-conductive layers. Glue is filled along the
adhesive-filling groove to be guided into a gap between the LED
chip and the sub-mount.
Inventors: |
Lee; Chia-En; (Chiayi City,
TW) ; Kuo; Cheng-Ta; (Hsinchu City, TW) ;
Hsia; Der-Ling; (New Taipei City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lextar Electronics Corporation |
Hsinchu |
|
TW |
|
|
Family ID: |
51350578 |
Appl. No.: |
15/259266 |
Filed: |
September 8, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14175419 |
Feb 7, 2014 |
9461213 |
|
|
15259266 |
|
|
|
|
Current U.S.
Class: |
438/27 |
Current CPC
Class: |
H01L 2933/0066 20130101;
H01L 33/486 20130101; H01L 33/22 20130101; H01L 2224/13 20130101;
H01L 33/62 20130101; H01L 33/0093 20200501 |
International
Class: |
H01L 33/62 20060101
H01L033/62; H01L 33/22 20060101 H01L033/22; H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2013 |
TW |
102105551 |
Claims
1. A light emitting device manufacturing method comprising:
providing a sub-mount, which has a plurality of
electrical-conductive layers, and a surface between every adjacent
two of the electrical-conductive layers has an adhesive-filling
groove; mounting an LED chip, which has a bottom substrate, on the
sub-mount by a flip-chip way, and two electrodes of the LED chip
are in contact with adjacent two of the electrical-conductive
layers; and filling an glue along the adhesive-filling groove to be
guided into a gap between the LED chip and the sub-mount.
2. The light emitting device manufacturing method of claim 1
further comprising a laser liftoff step to remove the bottom
substrate of the LED chip to expose a surface of the LED chip.
3. The light emitting device manufacturing method of claim 2
further comprising a roughening treatment applied to the exposed
surface of the LED chip.
4. The light emitting device manufacturing method of claim 1,
wherein the adhesive-filling groove has a depth ranging from 5
microns to 100 microns.
5. The light emitting device manufacturing method of claim 1,
wherein the adhesive-filling groove has a width ranging from 25
microns to 500 microns.
6. The light emitting device manufacturing method of claim 1
further comprising a eutectic bonding process to mount the LED chip
on the sub-mount.
7. The light emitting device manufacturing method of claim 1,
wherein the adjacent two of the electrical-conductive layers are in
direct contact with an outer side surface of the adhesive-filling
groove and not in direct contact with an inner side surface of the
adhesive-filling groove.
Description
RELATED APPLICATIONS
[0001] This application is a Divisional Application of the U.S.
application Ser. No. 14/175,419, filed Feb. 7, 2014, which claims
priority to Taiwan Application Serial Number 102105551, filed Feb.
18, 2013, all of which are herein incorporated by reference.
BACKGROUND
[0002] Field of Invention
[0003] The present invention relates to an LED sub-mount and a
method for manufacturing the light-emitting device using the LED
sub-mount.
[0004] Description of Related Art
[0005] A light emitting diode (LED) is a semiconductor
light-emitting device, which is equipped with low power
consumption, high luminous efficiency, long life and other
environmental advantages that the traditional lights can hardly
reach. In addition, different color LEDs, such as blue,
ultraviolet, red and white LEDs were developed one by one, thereby
making LEDs are more selective, and becoming one of the important
light-emitting devices today.
[0006] A conventional LED chip is mounted on a substrate by several
ways. For example, an adhesive may be dispensed on a bottom surface
of an emitting diode chip and mount the emitting diode chip on the
bonding area on the substrate with the adhesive. Another way is
using a eutectic bonding process to mount an LED chip on the
substrate, that is, the LED chip is fixed to the substrate by a
flip-chip way and the LED chip has a eutectic layer on its
electrode. When the eutectic layer on the electrode is heated over
a eutectic temperature, the eutectic layer melts and rapidly cures
so as to bond the LED chip on the substrate.
[0007] However, when the eutectic bonding process is used to mount
an LED chip on the substrate, the LED chip may be damaged if a
bottom substrate of the LED chip is removed by using a laser
liftoff process. Without removing the bottom substrate of the LED
chip, the light extraction efficiency of the LED chip can hardly be
improved.
SUMMARY
[0008] It is therefore an objective of the present invention to
provide an improved LED sub-mount and a method for manufacturing
the light-emitting device using the LED sub-mount.
[0009] In accordance with the foregoing and other objectives of the
present invention, a LED sub-mount includes a substrate body and a
plurality of first electrical-conductive layers. The substrate body
has a first surface. The first electrical-conductive layers are
positioned on the first surface of the substrate body, wherein the
first surface between every adjacent two of the first
electrical-conductive layers has an adhesive-filling groove.
[0010] According to another embodiment disclosed herein, the
substrate body further includes a second surface opposite to the
first surface, the second surface has a plurality of second
electrical-conductive layers disposed thereon, each of the second
electrical-conductive layers is aligned with a corresponding first
electrical-conductive layer and electrically connected with the
corresponding first electrical-conductive layer via a through hole
of the substrate body.
[0011] According to another embodiment disclosed herein, the
substrate body includes a silicon substrate.
[0012] According to another embodiment disclosed herein, the
adhesive-filling groove has a depth ranging from 5 microns to 100
microns.
[0013] According to another embodiment disclosed herein, the
adhesive-filling groove has a width ranging from 25 microns to 500
microns.
[0014] In accordance with the foregoing and other objectives of the
present invention, a light emitting device manufacturing method
includes the steps of providing a sub-mount, which has a plurality
of electrical-conductive layers, and a surface between every
adjacent two of the electrical-conductive layers has an
adhesive-filling groove; mounting an LED chip, which has a bottom
substrate, on the sub-mount by a flip-chip way, and two electrodes
of the LED chip are in contact with adjacent two of the
electrical-conductive layers; filling an glue along the
adhesive-filling groove to be guided into a gap between the LED
chip and the sub-mount; and removing the bottom substrate of the
LED chip.
[0015] According to another embodiment disclosed herein, the light
emitting device manufacturing method further includes a laser
liftoff step to remove the bottom substrate of the LED chip to
expose a surface of the LED chip.
[0016] According to another embodiment disclosed herein, the light
emitting device manufacturing method further includes a roughening
treatment applied to the exposed surface of the LED chip.
[0017] According to another embodiment disclosed herein, the
adhesive-filling groove has a depth ranging from 5 microns to 100
microns.
[0018] According to another embodiment disclosed herein, the
adhesive-filling groove has a width ranging from 25 microns to 500
microns.
[0019] According to another embodiment disclosed herein, the light
emitting device manufacturing method further includes a eutectic
bonding process to mount the LED chip on the sub-mount.
[0020] Thus, the LED sub-mount and method for manufacturing the
light-emitting device using the sub-mount disclosed herein enable
the glue or adhesive to be easily filled into the adhesive-filling
groove and guided into a gap between the LED chip and the
sub-mount, thereby reducing the probability to damage LED chip
while removing a bottom substrate of the LED chip using a laser
liftoff step and improving the light extraction efficiency of LED
chip. A roughening treatment is then applied to the exposed surface
of the LED chips to enable the emitting light of the LED chips more
uniform.
[0021] It is to be understood that both the foregoing general
description and the following detailed description are by examples,
and are intended to provide further explanation of the invention as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention can be more fully understood by reading the
following detailed description of the embodiment, with reference
made to the accompanying drawings as follows:
[0023] FIG. 1A illustrates a cross-sectional view of a LED
sub-mount according to a first embodiment of this invention;
[0024] FIG. 1B illustrates a top view of the LED sub-mount in FIG.
1A;
[0025] FIG. 2A illustrates a cross-sectional view of a LED
sub-mount according to a second embodiment of this invention;
[0026] FIG. 2B illustrates a top view of the LED sub-mount in FIG.
2A;
[0027] FIG. 3A illustrates a cross-sectional view of a LED
sub-mount according to a third embodiment of this invention;
[0028] FIG. 3B illustrates a top view of the LED sub-mount in FIG.
3A;
[0029] FIG. 4A illustrates a cross-sectional view of a LED
sub-mount according to a fourth embodiment of this invention;
[0030] FIG. 4B illustrates a top view of the LED sub-mount in FIG.
4A;
[0031] FIGS. 5A-5D illustrate a series of cross-sectional views to
demonstrate a light emitting device manufacturing method according
to an embodiment of this invention; and
[0032] FIGS. 6-7 illustrate a series of cross-sectional views to
demonstrate a light emitting device manufacturing method according
to another embodiment of this invention.
DETAILED DESCRIPTION
[0033] Reference will now be made in detail to the present
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers are used in the drawings and the description to refer to
the same or like parts.
[0034] In order to solve the drawbacks associated with the use of
conventional eutectic layer flip-chip die-bonding process, the
present invention provides a suitable LED sub-mount and
manufacturing method using the LED sub-mount, such that the
subsequent removal of a bottom substrate of the LED chip using a
laser liftoff step has less probability to damage the LED chip and
the light extraction efficiency of LED chip can be improved. The
sub-mount and manufacturing method using the sub-mount are
described in detail with the drawings.
[0035] Referring to both FIG. 1A and FIG. 1B, FIG. 1A illustrates a
cross-sectional view of a LED sub-mount according to a first
embodiment of this invention, and FIG. 1B illustrates a top view of
the LED sub-mount in FIG. 1A. A sub-mount 100 includes a substrate
body 102 and two first electrical-conductive layers 104. The first
electrical-conductive layer 104 is positioned on a first surface
102a of the substrate body 102. A first surface between two
(immediately) adjacent first electrical-conductive layers 104 has
an adhesive-filling groove 106 thereon. The adhesive-filling groove
106 is used to be filled by a glue or adhesive. The
adhesive-filling groove 106 is designed to have such dimensions for
the glue or adhesive to be easily filled into the adhesive-filling
groove 106 and guided into a gap between the LED chip and the
sub-mount 100. In this embodiment, the adhesive-filling groove 106
has a depth (d) ranging from 5 microns to 100 microns, but not
being limited to. The adhesive-filling groove 106 has a width (w)
ranging from 25 microns to 500 microns, but not being limited to.
In addition, the substrate body 102 may be a silicon substrate, but
not being limited to.
[0036] Referring to both FIG. 2A and FIG. 2B, FIG. 2A illustrates a
cross-sectional view of a LED sub-mount according to a second
embodiment of this invention, and FIG. 2B illustrates a top view of
the LED sub-mount in FIG. 2A. The second embodiment is different
from the first embodiment in that the sub-mount 100' has
electrical-conductive layers at two opposite surfaces thereof, and
the sub-mount 100 has electrical-conductive layers at one side
surface only. The sub-mount 100' includes a substrate body 102',
two first electrical-conductive layers 104a and two second
electrical-conductive layers 104b. The first electrical-conductive
layer 104a is positioned on the first surface 102a of the substrate
body 102' while the second electrical-conductive layer 104b is
positioned on a second surface 102b of the substrate body 102'. The
first surface 102a and the second surface 102b are two opposite
surfaces of the substrate body 102'. In addition, each second
electrical-conductive layer 104b is aligned with a corresponding
first electrical-conductive layer 104a and is electrically
connected with the corresponding first electrical-conductive layer
104a via a through hole 108 of the substrate body 102' (i.e., via
an electrical-conductive layer 104c inside the through hole 108).
The sub-mount 100' can be as a substrate for mounting a surface
mounting device thereon. A first surface between two (immediately)
adjacent first electrical-conductive layers 104a has an
adhesive-filling groove 106 thereon. The adhesive-filling groove
106 is used to be filled by a glue or adhesive. The
adhesive-filling groove 106 is designed to have such dimensions for
the glue or adhesive to be easily filled into the adhesive-filling
groove 106 and guided into a gap between the LED chip and the
sub-mount 100'. Similarly, the adhesive-filling groove 106 has a
depth ranging from 5 microns to 100 microns, but not being limited
to. The adhesive-filling groove 106 has a width ranging from 25
microns to 500 microns, but not being limited to. In addition, the
substrate body 102' may be a silicon substrate, but not being
limited to.
[0037] Referring to both FIG. 3A and FIG. 3B, FIG. 3A illustrates a
cross-sectional view of a LED sub-mount according to a third
embodiment of this invention, and FIG. 3B illustrates a top view of
the LED sub-mount in FIG. 3A. The third embodiment is different
from the first embodiment in that the sub-mount 200a is used for
mounting multiple LED chips thereon while the sub-mount 100 is used
for mounting a single LED chip thereon only. The sub-mount 200a
includes a substrate body 202a and four or more first
electrical-conductive layers 204. The first electrical-conductive
layer 204 is positioned on the first surface of the substrate body
202a. A first surface between two (immediately) adjacent first
electrical-conductive layers 204 has an adhesive-filling groove 206
thereon such that the sub-mount 200a can be used to mount three LED
chips (210a, 210b, 210c) thereon, and each LED chip crosses a
corresponding adhesive-filling groove 206. The adhesive-filling
groove 206 is used to be filled by a glue or adhesive. The
adhesive-filling groove 206 is designed to have such dimensions for
the glue or adhesive to be easily filled into the adhesive-filling
groove 206 and guided into a gap between the LED chip and the
sub-mount 200a. In this embodiment, the adhesive-filling groove 206
has a depth ranging from 5 microns to 100 microns, but not being
limited to. The adhesive-filling groove 206 has a width ranging
from 25 microns to 500 microns, but not being limited to. In
addition, the substrate body 202a may be a silicon substrate, but
not being limited to.
[0038] Referring to both FIG. 4A and FIG. 4B, FIG. 4A illustrates a
cross-sectional view of a LED sub-mount according to a fourth
embodiment of this invention, and FIG. 4B illustrates a top view of
the LED sub-mount in FIG. 4A. The fourth embodiment is different
from the third embodiment in that the sub-mount 200b is used for
mounting multiple LED chips in two-dimension array while the
sub-mount 200a is used for mounting LED chips in one-dimension
array. The sub-mount 200b includes a substrate body 202b and three
first electrical-conductive layers 204a. The first
electrical-conductive layer 204a is positioned on the first surface
of the substrate body 202b. A first surface between two
(immediately) adjacent first electrical-conductive layers 204a has
an adhesive-filling groove 206, and the first electrical-conductive
layer 204a is wider (compared with the first electrical-conductive
layer 204). Therefore, the sub-mount 200b can be used to mount four
LED chips (210d, 210e, 210f, 210g), and each LED chip crosses a
corresponding adhesive-filling groove 206. The adhesive-filling
groove 206 is used to be filled by a glue or adhesive. The
adhesive-filling groove 206 is designed to have such dimensions for
the glue or adhesive to be easily filled into the adhesive-filling
groove 206 and guided into a gap between the LED chip and the
sub-mount 200b. In this embodiment, the adhesive-filling groove 206
has a depth ranging from 5 microns to 100 microns, but not being
limited to. The adhesive-filling groove 206 has a width ranging
from 25 microns to 500 microns, but not being limited to. In
addition, the substrate body 202a may be a silicon substrate, but
not being limited to.
[0039] FIGS. 5A-5D illustrate a series of cross-sectional views to
demonstrate a light emitting device 300 manufacturing method
according to an embodiment of this invention. In FIG. 5A, a LED
chip 210 with a bottom substrate 212 is mounted on a sub-mount 100
by a flip-chip way, and two electrodes of the LED chip 210 are in
contact with adjacent two of the electrical-conductive layers 104.
When the LED chip 210 is mounted on the sub-mount 100 by a eutectic
bonding process, a gap between the LED chip 210 and the sub-mount
100 is less than 3 microns, which is not conducive to filling an
adhesive to the gap between the LED chip 210 and the sub-mount 100.
In FIG. 5B, the adhesive-filling groove 106 is designed to have
such dimensions for the glue or adhesive 110 to be easily filled
into the adhesive-filling groove 106 and guided into the gap
between the LED chip 210 and the sub-mount 100. In FIG. 5C, when
the glue or adhesive 110 filled into the adhesive-filling groove
106 is cured, a laser liftoff step may be used to remove the bottom
substrate 212 of the LED chip 210 to expose a surface of the LED
chip 210. Because the glue or adhesive 110 filled between the LED
chip 210 and the sub-mount 100 is cured, the removing force applied
to the bottom substrate 212 has less chance to damage the LED chip
210 when the LED chip 210 is reliably mounted on the sub-mount 100.
In FIG. 5D, after removing the bottom substrate 212, an emitting
surface of the LED chip 210 forms a rough surface 213 to enable the
emitting light more uniform.
[0040] FIGS. 6-7 illustrate a series of cross-sectional views to
demonstrate a light emitting device manufacturing method according
to another embodiment of this invention. The manufacturing method
of FIGS. 5A-5D is also used to mount multiple LED chips (210a,
210b, 210c) on the sub-mount 200a and fill the glue into the
adhesive-filling groove 206. After the glue within the
adhesive-filling groove 206 is cured, a substrate removal step,
e.g., a laser liftoff step, is used to remove a bottom substrate
(212a, 212b, 212c) of the LED chips (210a, 210b, 210c) so as to
improve the light extraction efficiency of LED chip. A roughening
treatment is applied to the exposed surface of the LED chips (210a,
210b, 210c) to form rough surfaces (213a, 213b, 213c) so as to
enable the emitting light of the LED chips (210a, 210b, 210c) more
uniform.
[0041] According to the above-discussed embodiments, the LED
sub-mount and method for manufacturing the light-emitting device
using the LED sub-mount disclosed herein enable the glue or
adhesive to be easily filled into the adhesive-filling groove and
guided into a gap between the LED chip and the sub-mount, thereby
reducing the probability to damage LED chip while removing a bottom
substrate of the LED chip using a laser liftoff step and improving
the light extraction efficiency of LED chip. A roughening treatment
is then applied to the exposed surface of the LED chips to enable
the emitting light of the LED chips more uniform.
[0042] Although the present invention has been described in
considerable detail with reference to certain embodiments thereof,
other embodiments are possible. Therefore, the spirit and scope of
the appended claims should not be limited to the description of the
embodiments contained herein.
[0043] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims.
* * * * *