KR100658939B1 - Package for light emitting device - Google Patents

Abstract

The present invention relates to a package of a light emitting device, wherein an active layer and a second polar layer are sequentially formed on an upper portion of a first polar layer, and an electrode for ohmic contact and reflection is formed below the first polar layer. A light emitting device in which electrode pads are formed on the two polar layers; A metal substrate having an insulating layer having an opening at an upper surface thereof, a solder formed at an upper surface exposed through the opening, and a conductive line formed over the insulating layer; A wire electrically connecting the electrode pad of the light emitting device and the conductive line; And a metal support thin film interposed between the ohmic contact and reflection electrode and the solder to bond the light emitting element to the metal substrate.

Therefore, the present invention has the effect of maximizing heat dissipation and obtaining a uniform flow of current by removing the dielectric on the surface to which the light emitting device and the metal substrate are bonded and directly performing metal bonding.

In addition, the present invention has the effect of maximizing the light output by allowing the current to flow vertically and uniformly by using the device from which the substrate on which the light emitting device has been grown is removed.

Light Emitting Diode, Dielectric, Solder, Sidewall, Slope, Support, Metal

Description

 Package for light emitting device

1 is a cross-sectional view showing a state in which a light emitting device is bonded to a metal substrate according to the prior art

2 is a cross-sectional view showing a state in which a light emitting device is bonded to a metal substrate using a submount substrate according to the related art.

3 is a cross-sectional view of a package of a light emitting device according to the first embodiment of the present invention.

4 is a cross-sectional view of a package of a light emitting device according to a second embodiment of the present invention.

5A and 5B are schematic cross-sectional views illustrating a package of a light emitting device according to a third embodiment of the present invention.

6 is a cross-sectional view of a package of a light emitting device according to a fourth embodiment of the present invention.

7 is a cross-sectional view of a package of a light emitting device according to a fifth embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: metal substrate 101510: groove

110: insulating layer 120: conductive line

150,450 solder 160,460 metal support thin film

200,220,400,420,600,620: Polar layer 210,410,610: Active layer

250: ohmic contact layer 260: electrode layer for reflection

270: electrode pad 290,530: dielectric film

300: lens 430,520: electrode for ohmic contact and reflection

455: electrode pad 500: metal support

The present invention relates to a package of a light emitting device, and more particularly, a light emitting device capable of maximizing heat emission and obtaining a uniform flow of current by removing a dielectric on a surface to which a light emitting device and a metal substrate are bonded and directly performing metal bonding. Relates to a package of devices.

In recent years, in the case of a high brightness and high output optical device package, the light output and its reliability are the biggest issues.

Among them, a light emitting diode for a backlight unit (BLU), which has recently been in the spotlight, has emerged as the biggest problem. The most critical problem of the reliability is a heat problem occurring in an optical device.

The heat generated inside the optical device not only degrades the characteristics of the optical device but also shortens the lifetime of the device.

Currently, many optical device makers consider the heat dissipation problem of the device most seriously when designing the package structure.

However, most of the area of the device is first covered with a dielectric (Dielectric), and then bonded using a heat transfer material having excellent heat transfer characteristics.

1 is a cross-sectional view illustrating a state in which a light emitting device is bonded to a metal substrate according to the prior art. First, a light emitting device includes an N-GaN layer 21, an active layer 22, and a P-GaN layer on a substrate 20. (23) are sequentially stacked; Mesa-etched from the P-GaN layer 23 to a part of the N-GaN layer 21; An ohmic contact and reflection electrode 24 is formed on the P-GaN layer 23; A P-electrode pad 31 is formed on one region of the ohmic contact and reflection electrode 24; A dielectric layer 35 is formed on the remaining regions of the ohmic contact and reflection electrode 24 where the P-electrode pad 31 is not formed; A thermal contact layer 41 is formed on the dielectric layer 35; The N-electrode 32 is formed on the mesa-etched N-GaN layer 21.

The metal substrate 10 has an opening 15 formed thereon and a dielectric layer 11 is formed, and a conductive line 12 is formed on the dielectric layer 11.

The light emitting device is turned upside down on the metal substrate 10 and the electrode pads 31 and 32 are flip chip bonded to the solder 35 on the conductive line 12 and mounted.

The thermal contact layer 41 is bonded to the metal substrate 10 exposed by the opening 15 with the heat transfer material layer 42 interposed therebetween.

After the light emitting device is bonded to the metal substrate as described above, the lens 50 is bonded to the metal substrate while surrounding the light emitting device.

Therefore, the light emitting device according to the prior art covers the device surface with a dielectric, which is a non-conductive material, for bonding the widest area of the device surface to the metal substrate, and then joins the metal substrate using a contact material having excellent heat transfer characteristics. will be.

FIG. 2 is a cross-sectional view illustrating a state in which a light emitting device is bonded to a metal substrate using a submount substrate according to the related art. In the case of using a submount substrate, FIG. 2 shows a conductive line 81 formed thereon. ) Prepares a submount substrate 80 electrically connected to a lower conductive line (not shown), and solder bumps 71 on the conductive line 81 on the submount substrate 80. Bonding the light emitting device 70 to each other, and the conductive line under the submount substrate 80 may be flip-chip using the conductive line 62 and the solder 85 formed on the metal substrate 60. Flip chip) is bonded.

In addition, a thermal contact layer 87 is provided under the submount substrate 80, and the thermal contact layer 87 is bonded by the upper portion of the metal substrate 60 and the heat transfer material layer 90.

After the light emitting device is bonded to the metal substrate, the light emitting device surrounds the light emitting device and bonds the lens 50 to the metal substrate 60.

Here, '62' in FIG. 2 is a dielectric layer.

Such a technology of bonding a light emitting device and a metal substrate using a sub-mount substrate has a large area of the light emitting device covered with a dielectric layer which is an insulating material, and a relatively small area is bonded to the submount substrate with solder. .

Therefore, as described above, since the dielectric layer is present in most of the regions where the light emitting element and the metal substrate are bonded, heat transfer from the light emitting element to the metal substrate is not smooth and an electrode contact portion must be made. have.

In order to solve the problems described above, the present invention provides a light emitting device capable of maximizing heat dissipation and obtaining a uniform flow of current by removing a dielectric on a surface to which a light emitting device and a metal substrate are bonded and directly performing metal bonding. The purpose is to provide a package.

Another object of the present invention is to provide a package of a light emitting device capable of maximizing light output by allowing a current to flow uniformly vertically by using a device having a substrate on which an epitaxial light emitting device is grown.

According to a preferred aspect of the present invention, an active layer and a second polar layer are sequentially formed on a first polar layer, and an electrode for ohmic contact and reflection is formed below the first polar layer. And a light emitting device in which electrode pads are formed on the second polar layer;

A metal substrate having an insulating layer having an opening at an upper surface thereof, a solder formed at an upper surface exposed through the opening, and a conductive line formed over the insulating layer;

A wire electrically connecting the electrode pad of the light emitting device and the conductive line;

Provided is a package of a light emitting device including a metal support thin film interposed between the ohmic contact and reflective electrode and a solder to bond the light emitting device to the metal substrate.

According to another preferred aspect of the present invention, an active layer and a second polar layer are sequentially formed on the first polar layer, and gradually from the second polar layer to the first polar layer. A light emitting device in which a sidewall is inclined in a shape of increasing width, and an electrode pad is formed on the second polar layer;

A metal support part having a groove formed on an upper surface thereof, and the light emitting device bonded to an inner surface of the groove;

A metal substrate having an insulating layer having an opening at an upper surface thereof, and having a conductive line formed over the insulating layer;

Solder bonding the metal support to the upper portion of the metal substrate exposed through the opening;

Provided is a package of a light emitting device comprising an electrode pad of the light emitting device and a wire electrically connected to the conductive line.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a cross-sectional view of a package of a light emitting device according to a first embodiment of the present invention, in which an active layer 210 and a second polar layer 220 are sequentially formed on the first polar layer 200. A light emitting device in which ohmic contacts and reflection electrodes are formed below the first polar layer 200, and electrode pads 270 are formed on the second polar layer 220; An insulating layer 110 having an opening 111 is formed on an upper surface thereof, a solder 150 is formed on an upper surface exposed by the opening 111, and a conductive line is formed on the insulating layer 110. A metal substrate 100 on which 120 is formed; A wire 280 electrically connected to the electrode pad 270 of the light emitting device and the conductive line 120; The metal support thin film 160 is interposed between the ohmic contact and reflection electrodes 250 and 260 and the solder 150 to bond the light emitting device to the metal substrate 100.

The ohmic contact and reflection electrodes may use one electrode for performing ohmic contact and reflection functions, and an ohmic contact layer 250 and a reflective electrode layer 260 may be stacked.

The lens 300 including the light emitting element and the wire is attached to the upper portion of the metal substrate 100.

In addition, a dielectric film 290 is formed on sidewalls of the first polar layer 200 to the second polar layer 220.

Here, the dielectric layer 290 may be used to protect the sidewall of the device, but the HR (High) reflects the light emitted from the active layer 210 of the light emitting device to prevent the light from escaping to the sidewall of the device so that the dielectric layer 290 is emitted to the top of the device. Reflective dielectric films such as films are preferred.

4 is a cross-sectional view of a package of a light emitting device according to a second embodiment of the present invention, in which an active layer 410 and a second polar layer 420 are sequentially formed on the first polar layer 400. A light emitting device in which ohmic contacts and reflection electrodes 430 are formed below the second polar layer 420, and electrode pads 455 are formed on the second polar layer 420; The groove 101 is formed on the upper surface, the solder 450 is coated on the inner surface of the groove 101, and the insulating layer 110 is formed on the upper surface on which the groove 101 is not formed. A metal substrate 100 having conductive lines 120 formed on the insulating layer 110; A wire 470 electrically connecting the electrode pad 455 and the conductive line 120 of the light emitting device; In order to bond the light emitting device and the metal substrate 100, the metal support thin film 460 is interposed between the ohmic contact and reflection electrode 430 and the solder 450.

As such, the light emitting devices of the first and second exemplary embodiments of the present invention are bonded to the metal substrate 100 through the metal support thin films 160 and 460, thereby increasing heat dissipation efficiency and simplifying the structure of the package.

5A and 5B are schematic cross-sectional views illustrating a package of a light emitting device according to a third embodiment of the present invention. First, in FIG. 5A, a second polar layer 220 of the first polar layer 200 of the light emitting device is illustrated. The side wall is inclined in a shape in which the width increases from the second polar layer 220 to the first polar layer 200.

A dielectric film 290 is formed on the sidewall, and an ohmic contact layer 250 and a reflective electrode layer 260 are stacked below the second polar layer 220.

Here, the dielectric layer 290 may be used to protect the sidewall of the device, but the HR (High) reflects the light emitted from the active layer 210 of the light emitting device to prevent the light from escaping to the sidewall of the device so that the dielectric layer 290 is emitted to the top of the device. Reflective dielectric films such as films are preferred.

When the sidewall of the light emitting device is inclined, the amount of light emitted to the upper part of the light emitting device can be increased.

In FIG. 5B, an ohmic contact and reflection electrode layer 430 surrounding the dielectric layer 290 and the lower portion of the second polar layer 220 is formed.

Therefore, this ohmic contact and reflection electrode layer 430 is bonded to the metal support thin film 160.

6 is a cross-sectional view of a package of a light emitting device according to a fourth embodiment of the present invention, in which an active layer 610 and a second polar layer 620 are sequentially formed on the first polar layer 600. The sidewalls are inclined in a shape in which the width increases from the second polarity layer 620 to the first polarity layer 600, a dielectric film 530 is formed on the sidewalls, and the sidewalls and the second polarity layer 620. A light emitting device in which an ohmic contact and reflection electrode 520 is formed below and an electrode pad 550 is formed on the second polar layer 620; A metal support part 500 having a groove 510 formed on an upper surface thereof and having an ohmic contact and reflection electrode 520 of the light emitting device bonded to an inner surface of the groove 510; An insulating layer 110 having an opening 111 is formed on an upper surface thereof, a solder 150 is formed on an upper surface exposed by the opening 111, and a conductive line is formed on the insulating layer 110. A metal substrate 100 on which 120 is formed; A solder (260) for bonding a metal support (550) on the metal substrate (100) exposed through the opening (111); The electrode pad 550 of the light emitting device and a wire 470 electrically connected to the conductive line 120 are configured.

7 is a cross-sectional view of a package of a light emitting device according to a fifth embodiment of the present invention, in which an active layer 610 and a second polar layer 620 are sequentially formed on the first polar layer 600. The sidewalls are inclined in a shape in which the width increases from the second polarity layer 620 to the first polarity layer 600, a dielectric film 530 is formed on the sidewalls, and the sidewalls and the second polarity layer 620. A light emitting device in which an ohmic contact and reflection electrode 520 is formed below and an electrode pad 550 is formed on the second polar layer 620; A metal support part 500 having a groove 510 formed on an upper surface thereof and having an ohmic contact and a reflective electrode 520 of the light emitting device bonded to an inner surface of the groove 510; The groove 101 is formed on the upper surface, the insulating layer 110 is formed on the upper surface where the groove 101 is not formed, and the conductive line 120 is formed on the insulating layer 110. A metal substrate 100; A wire 470 electrically connecting the electrode pad 455 and the conductive line 120 of the light emitting device; It is coated on the inner surface of the groove 101, and comprises a solder 450 for bonding the light emitting element inserted into the groove 101.

As described above, in the present invention, FIGS. 3 and 6 are bonded to the light emitting device on the metal substrate, and FIGS. 4 and 7 are to make a groove in the metal substrate and bond the light emitting device to the inner surface of the groove, 6 and 7 show that the light emitting device is bonded to a metal support having a groove formed thereon, and then the metal support is bonded to the metal substrate.

Therefore, the light emitting elements of the first to fifth embodiments of the present invention are bonded using solder without interposing a dielectric on each bonded area.

Therefore, the present invention has an advantage in that the dielectric is removed from the surface where the light emitting device and the metal substrate are bonded, and the metal is directly bonded to maximize heat dissipation and obtain a uniform flow of current.

In addition, the present invention removes the substrate used for epitaxial growth for the light emitting device, and allows the current to flow uniformly vertically, thereby maximizing the light output.

As described above, the present invention has the effect of maximizing heat dissipation and obtaining a uniform flow of current by removing the dielectric on the surface to which the light emitting device and the metal substrate are bonded and directly performing metal bonding.

In addition, the present invention has the effect of maximizing the light output by allowing the current to flow vertically and uniformly by using the device from which the substrate on which the light emitting device has been grown is removed.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (9)

The active layer and the second polar layer are sequentially formed on the first polar layer, ohmic contact and reflection electrodes are formed below the first polar layer, and electrode pads are formed on the second polar layer. A light emitting element; A dielectric film formed on sidewalls of the light emitting element from the first polar layer to the second polar layer; A metal substrate having an insulating layer having an opening at an upper surface thereof, a solder formed at an upper surface exposed through the opening, and a conductive line formed over the insulating layer; A wire electrically connecting the electrode pad of the light emitting device to the conductive line of the metal substrate; And a metal support thin film interposed between the ohmic contact and reflective electrodes and a solder to bond the light emitting element and the metal substrate. The method of claim 1, A groove is formed in the opening of the metal substrate, Solder is formed on the inner surface of the groove, The light emitting device is a package of a light emitting device, characterized in that inserted into the groove and bonded by solder through a metal support thin film. The method of claim 1, Sidewalls from the first polar layer to the second polar layer of the light emitting device, The package of the light emitting device, characterized in that inclined in a shape that increases in width from the second polar layer to the first polar layer. delete The method according to any one of claims 1 to 3, The package of the light emitting device, characterized in that the lens surrounding the light emitting device and the wire is further bonded to the upper portion of the metal substrate. The active layer and the second polar layer are sequentially formed on the first polar layer, the sidewalls are inclined in a shape in which the width increases from the second polar layer to the first polar layer, and the electrode is disposed on the second polar layer. A light emitting element in which pads are formed; A dielectric film formed on sidewalls of the light emitting element; A metal support part having a groove formed on an upper surface thereof, and the light emitting device bonded to an inner surface of the groove; A metal substrate having an insulating layer having an opening at an upper surface thereof, and having a conductive line formed over the insulating layer; Solder bonding the metal support to the upper portion of the metal substrate exposed through the opening; And a wire for electrically connecting the electrode pad of the light emitting device and the conductive line of the metal substrate. The method of claim 6, The ohmic contact and reflection electrodes are further formed on an outer surface of the dielectric film on the sidewall of the light emitting device and under the second polar layer. The ohmic contact and the reflection electrode is bonded to the inner surface of the groove of the metal support portion package of the light emitting device. The method according to claim 6 or 7, A groove is formed in the opening of the metal substrate, The solder is formed on the inner surface of the groove, And the metal support part is inserted into the groove and bonded to the metal substrate by the solder. The method according to claim 6 or 7, The package of the light emitting device, characterized in that the lens surrounding the light emitting device and the wire is further bonded to the upper portion of the metal substrate.

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