KR100866879B1 - Light emitting device package and its manufacturing method - Google Patents

Abstract

The present invention relates to a light emitting device package and a method for manufacturing the same, and more particularly, to a light emitting device package capable of emitting uniform white light and a method of manufacturing the same. The present invention is a light emitting device package, the package body; An electrode formed on at least one side of the package body; A light emitting device mounted on the package body; It is preferable that the light emitting device is configured to include a phosphor layer surrounding the uniform thickness.

Light emitting elements, electrodes, packages, phosphors, LEDs.

Description

Light emitting device package and its manufacturing method {LED package and method of manufacturing the same}

1 is a cross-sectional view showing an example of a general white light emitting device package.

2 to 4 is a view showing a manufacturing process of the light emitting device package of the present invention,

  2 is a cross-sectional view showing a state where an electrode is formed on a substrate.

  3 is a cross-sectional view illustrating an example in which a reflective film is formed on a substrate.

  4 is a cross-sectional view showing a state in which a phosphor layer is formed on a light emitting element mounted on a substrate.

5 is a cross-sectional view showing an example of a light emitting unit using the light emitting device package of the present invention.

6 is a cross-sectional view showing another example of a light emitting unit using the light emitting device package of the present invention.

<Brief description of the main parts of the drawing>

10 substrate 20 electrode

21: upper electrode 22: lower electrode

23 connection electrode 30 reflecting film

40: light emitting element 50: phosphor layer

100: light emitting device package 110: lens

The present invention relates to a light emitting device package and a method for manufacturing the same, and more particularly, to a light emitting device package capable of emitting uniform white light and a method of manufacturing the same.

Light Emitting Diodes (LEDs) are well-known semiconductor light emitting devices that convert current into light.In 1962, red LEDs using GaAsP compound semiconductors were commercialized, along with GaP: N series green LEDs. It has been used as a light source for display images of electronic devices, including.

The wavelength of light emitted by such LEDs depends on the semiconductor material used to make the LEDs. This is because the wavelength of the emitted light depends on the band-gap of the semiconductor material, which represents the energy difference between the valence band electrons and the conduction band electrons.

Gallium nitride compound semiconductors (Gallium Nitride (GaN)) have attracted much attention in the field of high power electronics development due to their high thermal stability and wide bandgap (0.8-6.2 eV). One reason for this is that GaN can be combined with other elements (indium (In), aluminum (Al), etc.) to produce semiconductor layers that emit green, blue and white light.

In this way, the emission wavelength can be adjusted to match the material's characteristics to specific device characteristics. For example, GaN can be used to create white LEDs that can replace incandescent and blue LEDs that are beneficial for optical recording.

Methods of making such a white light source include a method of using an LED emitting light of three primary colors of red, green, and blue light, and a method of using a single light LED and a phosphor.

In the method using the phosphor, a white light source may be manufactured using a blue LED and a yellow phosphor, which is produced by mixing a blue light emitted from a blue LED and yellow light of a yellow phosphor excited and emitted by the blue light.

Similarly, white LEDs can be made using blue LEDs, green and red phosphors, ultraviolet (UV) LEDs, and red, green, and blue phosphors.

Among the methods for making such a white light source, a method using a blue LED and a yellow phosphor, as described above, emits red and green light according to the degree of blue light absorbed by the phosphor and emitted. It is mixed with blue light, making it visible to the viewer as white light.

The method of making a white light source using the blue LED and the yellow phosphor is not only excellent in color rendering, but also widely used because of its excellent stability and reliability.

Figure 1 shows an LED lamp for making a white light source using such LED and phosphor.

That is, such an LED lamp has a blue LED 3 coupled to the stack 2 in a reflecting cup 1 and filled with a filler 5 in which phosphor 4 is mixed in a silicone gel or epoxy on the upper side thereof. The glass 6 is located on this filler 5.

However, this LED lamp structure has a non-uniform thickness of the filler 5 surrounding the LED 3, so that the paths (a, b) until the light emitted from the LED (3) reaches the glass (6) surface ) A difference occurs.

Therefore, a difference occurs in the amount of the phosphor 4 reacting to the blue light of the LED 3 depending on the path of the light, there is a problem that can not obtain a uniform light.

In addition, there is a problem in that color reproducibility is deteriorated due to non-uniform distribution of phosphor grains included in the filler 5.

SUMMARY OF THE INVENTION The present invention provides a light emitting device package and a method of manufacturing the same, which can emit uniform white light by allowing light to be emitted while passing through an external medium so that the difference in the optical path of light emitted from the light emitting device is not large. To provide.

In order to achieve the above technical problem, the present invention, a light emitting device package, and a package body; An electrode formed on at least one side of the package body; A light emitting device mounted on the package body; It is preferable to include a phosphor layer surrounding the light emitting device to a uniform thickness.

In this case, the thickness of the phosphor layer formed on the upper surface of the light emitting device and the thickness of the phosphor layer formed on the side surface of the light emitting device is preferably the same.

The light emitting device may be flip-chip bonded to the electrode so that the light emitting surface is a flat surface, but a vertical light emitting device may be used.

As described above, since the phosphor layer surrounds the light emitting device with a uniform thickness, the external shape of the phosphor layer may have a rectangular parallelepiped shape similar to that of the light emitting device.

In addition, the width of the phosphor layer may be the same as the width of the package body.

On the other hand, the electrode, and the upper electrode formed on the upper surface of the package body; The lower surface of the package body may be configured to include a lower electrode connected to the upper electrode.

In this case, the upper electrode and the lower electrode may be connected to each other through a through hole formed in the package body.

On the other hand, it may further include a lens surrounding the entire light emitting device package.

As another aspect for achieving the above technical problem, the present invention, a method of manufacturing a light emitting device package, comprising: forming a plurality of pairs of electrodes on a substrate; Bonding a plurality of light emitting elements on the substrate to be connected to the pair of electrodes; Forming a phosphor layer on the substrate to which the light emitting device is bonded; The substrate and the phosphor layer are preferably configured to include the step of cutting the package unit.

In this case, the cutting in the package division unit may include a thickness of the phosphor layer formed on the upper surface of the light emitting device and a thickness of the phosphor layer formed on the side surface of the light emitting device exposed by the cutting.

In addition, the spacing of the plurality of light emitting devices may be twice the thickness of the phosphor layer formed on the upper surface of the light emitting device, or the length may be added to the thickness removed during the cutting process.

The forming of the plurality of pairs of electrodes may include forming an upper electrode on an upper surface of the substrate and a lower electrode connected to the upper electrode and positioned on a lower surface of the substrate.

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

While the invention allows for various modifications and variations, specific embodiments thereof are illustrated by way of example in the drawings and will be described in detail below. However, it is not intended to be exhaustive or to limit the invention to the precise forms disclosed, but rather the invention includes all modifications, equivalents, and alternatives consistent with the spirit of the invention as defined by the claims.

Like reference numerals denote like elements throughout the description of the drawings. In the drawings the dimensions of layers and regions are exaggerated for clarity. In addition, each embodiment described herein includes an embodiment of a complementary conductivity type.

When an element such as a layer, region or substrate is referred to as being on another component "on", it will be understood that it may be directly on another element or there may be an intermediate element in between. will be. If a part of a component, such as a surface, is expressed as 'inner', it will be understood that this means that it is farther from the outside of the device than other parts of the element.

Furthermore, relative terms such as "beneath" or "overlies" refer to the relationship of one layer or region to one layer or region and another layer or region with respect to the substrate or reference layer, as shown in the figures. Can be used to describe.

It will be understood that these terms are intended to include other directions of the device in addition to the direction depicted in the figures. Finally, the term 'directly' means that there is no element in between. As used herein, the term 'and / or' includes any and all combinations of one or more of the recorded related items.

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers, and / or regions, such elements, components, regions, layers, and / or regions It will be understood that it should not be limited by these terms.

These terms are only used to distinguish one element, component, region, layer or region from another region, layer or region. Thus, the first region, layer or region discussed below may be referred to as the second region, layer or region.

In manufacture of the light emitting element package of this invention, as shown in FIG. 2, the electrode 20 paired with the board | substrate 10 is first formed.

The electrode 20 is coupled to the front side electrode 21 for coupling the light emitting device to have electrical and structural strength in a later process, and to the structure for external power supply such as a PCB substrate with electrical and structural strength. It may be made of a back side electrode (22).

The upper electrode 21 and the lower electrode 22 may be connected to each other by a connecting electrode 23 formed in a through hole 11 formed by a bulk etching method on the substrate 10. have.

In the process of forming the electrode 20 on the substrate 10, first, a mask layer (not shown) is formed on the substrate 10 or a through hole 11 is formed using a substrate on which a mask layer is already formed. A mask pattern required for bulk etching of the region to be formed is formed.

The through hole 11 is formed by bulk etching (bulk micromachining) the substrate 10 using the mask pattern.

The substrate 10 may be a silicon substrate or aluminum, aluminum nitride (AlN), aluminum oxide (AlO _x ), photosensitive glass (PSG), Al ₂ O ₃ , BeO, PCB board, etc. can be used.

In addition, as a bulk etching method for forming the through hole 11, the through hole 11 may be formed by using a wet etching method, a dry etching method, or a laser drilling method. Can form.

A typical method of the dry etching method is a deep reactive ion etching method.

In addition, an etching process for forming the through hole 11 requires a mask layer (not shown) to distinguish between the portion to be etched and the portion to be protected from etching, and the mask layer to be used may perform dry or wet etching. In this case, the material may be used as a mask for a long time, and a silicon nitride film or a silicon oxide film may be used.

On the other hand, the through hole 11 for electrically connecting the upper electrode 21 and the lower electrode 22, respectively, the through hole for the positive electrode and the negative electrode to separate the positive electrode and the negative electrode 21, 22, respectively More preferably, two through holes 11 are formed by dividing into electrode through holes.

Next, an insulation layer (not shown) for electrical insulation is formed on the entire surface of the substrate 10. In this embodiment, to remove the mask layer (not shown) used to form the through-hole 11 to form the insulating layer, the silicon oxide film (silicon oxide film) excellent in insulating properties by the thermal oxidation method (thermal oxidation) ) Is formed on the entire surface of the substrate 10.

As an insulating layer forming method other than the above method, a silicon nitride film may be deposited by an LPCVD method or a PECVD method and used as an insulating layer (not shown).

On the other hand, when an insulating substrate such as aluminum nitride (AlN) or aluminum oxide (AlO _x ) is used as the substrate 10, the formation of the insulating layer may be omitted.

Next, the electrodes 21 and 22 are patterned in the structure in which the through hole 11 is formed.

As a method of forming the electrode 20, first, a photoresist is applied to the front or rear surface of the substrate 10, exposed and developed to separate the electrodes 21 and 22 from side to side, and the through holes 11 The upper electrode 21 formed on the front surface of the substrate 10 and the lower electrode 22 formed on the rear surface of the substrate 10 are patterned so as to be connected to each other or connected to each other by the connection electrode 23.

Thereafter, a metal for forming an electrode is deposited on the front or rear surface of the substrate 10 by a sputtering method or an E-beam evaporation method. Before depositing such a metal, a seed metal may be deposited first.

Next, the deposited metal is lifted off to form the electrode 50 on the front or back side.

After depositing a bonding metal (not shown) on the opposite side on which the metal is deposited, a photoresist is applied, exposed, and developed so that the positive electrode and the negative electrode are separated from each other.

Subsequently, the upper electrode 21 and the lower electrode 22 are patterned to be connected to the upper electrode 21 or the lower electrode 22 and the through hole 11 of the substrate 10 by electroplating or electroless plating. It is formed to be electrically connected by the connection electrode 23 formed in the through hole (11).

On the other hand, the electrodes 21, 22 may be formed by etching the bonding metal so that the left and right electrically separated from each other to form an electrode pair. These bonding metals should not only have excellent electrical properties, but also have excellent adhesion with the insulating film, and have excellent adhesion with the silicon oxide film commonly used as an insulating film, and are excellent in titanium, chromium (Cr), and tantalum (Ta). Or the like can be used as the adhesion layer.

In addition, gold (Au), copper (Cu), and aluminum (Al) may be used as representative materials of electrode metals having good electrical characteristics and which can be easily deposited in a semiconductor process.

The metal for forming the electrode is exposed to high temperatures when joining the components of the module during the post-process. At this time, Ti or Cr, which is an adhesion layer, may be diffused into Au, thereby reducing the electrical characteristics of Au. To prevent this, Ti / Pt / Au or Cr / Ni / Au, Cr using a diffusion barrier layer (not shown) such as platinum (Pt) and nickel (Ni) between the adhesive layer of Ti and Cr and Au The electrode 20 having a / Cu / Ni / Au structure can be formed.

Then, after forming the electrode 20, a reflective layer 30 may be formed on the upper side of the substrate 10 to improve the extraction efficiency of the light emitted from the light emitting device to be mounted later.

As the material for the reflective film 30, aluminum (Al) or silver (Ag) having excellent reflectivity may be used.

As a method of forming, first, the photoresist is coated on the entire surface, and the photoresist is exposed and developed to deposit the reflective film 30 metal on the bottom surface of the substrate 10 on which the light emitting device is to be mounted by a sputtering method or an E-beam deposition method. After lift off, it can form.

In addition, the reflective film 30 may be formed by depositing a metal on the entire surface of the reflective film 30 and etching an unnecessary portion after patterning.

In this case, the metal for forming the reflective film 30 should be formed so as not to be connected or overlapped with the pair of electrodes 20 at the same time so that an electric short circuit does not occur, and the electrode 30 is bonded to the electrode of the light emitting device. More preferably, the metal of the reflective film 30 is not formed in the region where the solder or the Au stud pump 41 (see FIG. 4) is formed.

Hereinafter, the process will be described in a state where the reflective film 30 is not formed.

Next, as illustrated in FIG. 4, the plurality of light emitting devices 40 are electrically connected to each pair of electrodes 20 by a method such as conductive solder or Au stud 41 bonding. do.

In FIG. 4, the light emitting device 40 is flip-chip bonded, but in some cases, a horizontal or vertical light emitting device may be wire-bonded and bonded.

Subsequently, the phosphor layer 50 covering and connecting the plurality of light emitting devices 40 as a whole is uniformly formed on the substrate 10 to which the light emitting device 40 is bonded.

The phosphor layer 50 may be formed using a material including phosphor powder in a light transmitting medium, and the light transmitting medium may use a resin such as epoxy or silicone gel.

In addition, the phosphor powder may be a phosphor that absorbs light emitted from the light emitting device 40 and emits light of lower energy. For example, the phosphor powder may be a yellow phosphor in which yellow light is emitted. In addition, the light emitting device 40 may be a light emitting device 40 that emits blue light. Therefore, the light of the blue light emitting device 40 and the yellow phosphor may be mixed to emit white light.

At this time, the phosphor layer 50 is filled flat to form a predetermined thickness (W1) on the upper surface of the light emitting device 40, the phosphor film having a uniform thickness on the light emitting surface, such as the top and side surfaces of the light emitting device 40 The junction spacing W4 between each of the light emitting elements 40 and the light emitting elements 40 to be bonded is adjusted to form (W1 = W2 = W3).

When the junction gap W4 between the light emitting device 40 and the light emitting device 40 is cut into a package structure including the substrate 10 and the phosphor layer 50 in each package unit 10, The width D1 of the substrate 10 and the phosphor layer 50 to be cut may be considered.

Accordingly, the distance W4 between the light emitting devices 40 may be cut at twice the distance W2 = W3 between the light emitting devices 40 and the outer surface of the phosphor layer 50 of each light emitting device package ( 10) and the width D1 of the phosphor layer 50 may be the distance (W4 = W2 + W3 + D1).

However, as long as the width D1 of the substrate 10 and the phosphor layer 50 to be cut is negligible, the distance W4 between the light emitting elements 40 is approximately equal to the light emitting elements of the individual light emitting device packages. It may be twice the distance (W2 = W3) between the 40 and the outer surface of the phosphor layer 50.

On the other hand, as described above, the phosphor layer 50 may be made of a mixture of a silicon gel or an epoxy (epoxy) excellent in the light transmittance and the phosphor powder.

In addition, as a solder material for bonding the light emitting device 40, gold tin (AuSn), red tin (PbSn), indium (In), or the like may be formed by a method such as E-beam evaporation. have.

Then, as shown in FIG. 5, the phosphor layer (W1 = W2 = W3) having a uniform thickness may be individually formed on the light emitting surface of the light emitting device 40 on the upper and lower surfaces of the light emitting device package in the wafer unit. Cut into the package 100.

The individual packages 100 cut and manufactured as described above may be bonded to the PCB substrate 200 to have electrical and structural bonding strengths for use in various applications such as a backlight unit or a lighting lamp.

In addition, as shown in FIG. 6, as illustrated in FIG. 6, the lens 110 may be packaged to have a shape designed to control the distribution of light emitted from the light emitting element 40 or to form a lens 110 for improving light efficiency. have.

The above embodiment is an example for explaining the technical idea of the present invention in detail, and the present invention is not limited to the above embodiment, various modifications are possible, and various embodiments of the technical idea are all protected by the present invention. It belongs to the scope.

According to the present invention as described above, the phosphor layer is uniformly formed on all surfaces to which the light of the light emitting element is radiated, so that a light source having uniform color distribution of light passing through the phosphor layer and excellent reproducibility can be obtained as well as wafer level. By implementing the phosphor layer, there is an effect that can produce a light emitting device package suitable for mass production.

Claims (11)

In the light emitting device package, Package body; An electrode formed on at least one side of the package body; A light emitting device mounted on the package body; The light emitting element is wrapped with a uniform thickness such that the thickness on the top surface of the light emitting element and the side surface of the light emitting element are substantially the same, and at least a portion of the horizontal cross-sectional area includes a phosphor layer substantially the same as the horizontal cross-sectional area of the package body. Light emitting device package, characterized in that configured to. delete The light emitting device package of claim 1, wherein the light emitting device is flip-chip bonded to the electrode. The light emitting device package according to claim 1, wherein an outer shape of the phosphor layer has a rectangular parallelepiped shape. The light emitting device package according to claim 1, wherein the width of the outer surface of the phosphor layer is the same as that of the package body. The light emitting device package of claim 1, further comprising a lens surrounding the entire light emitting device package. The method of claim 1, wherein the electrode, An upper electrode formed on an upper surface of the package body; And a lower electrode formed on a lower surface of the package body and connected to the upper electrode. The light emitting device package according to claim 7, wherein the upper electrode and the lower electrode are connected to each other through a through hole formed in the package body. In the manufacturing method of the light emitting device package, Forming a plurality of pairs of electrodes penetrating the substrate on the substrate; Bonding a plurality of light emitting elements on the substrate to be connected to the pair of electrodes; Forming a phosphor layer uniformly formed on an upper side of the plurality of light emitting elements and filling the spaces between the plurality of light emitting elements on an upper side of the substrate on which the plurality of light emitting elements are bonded; Cutting the substrate and the phosphor layer in package division units so that the thickness of the phosphor layer formed on the upper surface of the light emitting device and the thickness of the phosphor layer formed on the side surface of the light emitting device exposed by the separation process of the package are the same. Configured by The spacing of the plurality of light emitting devices, the method of manufacturing a light emitting device package, characterized in that twice the thickness of the phosphor layer formed on the upper surface of the light emitting device. delete In the manufacturing method of the light emitting device package, Forming a plurality of pairs of electrodes penetrating the substrate on the substrate; Bonding a plurality of light emitting elements on the substrate to be connected to the pair of electrodes; Forming a phosphor layer uniformly formed on an upper side of the plurality of light emitting elements and filling the spaces between the plurality of light emitting elements on an upper side of the substrate on which the plurality of light emitting elements are bonded; Cutting the substrate and the phosphor layer in package division units so that the thickness of the phosphor layer formed on the upper surface of the light emitting device and the thickness of the phosphor layer formed on the side surface of the light emitting device exposed by the separation process of the package are the same. Configured by The spacing of the plurality of light emitting devices, the length of the phosphor layer formed on the upper surface of the light emitting device package, characterized in that the length plus the thickness removed in the cutting process.

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