KR100958513B1 - Electrode pad and light emitting diode package including the same - Google Patents

Abstract

It includes a copper alloy layer, a nickel layer, and an antireflection prevention layer laminated sequentially, the antireflection prevention layer is ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum ( Disclosed is an electrode pad formed of at least one selected from the group consisting of Pt), and an alloy thereof, and a light emitting diode package including the electrode pad.

Copper alloy layer, nickel layer, silver layer, antireflective layer, platinum group element, light emitting diode package, electrode pad

Description

ELECTRODE PAD AND LIGHT EMITTING DIODE PACKAGE INCLUDING THE SAME}

The present invention relates to an electrode pad and a light emitting diode package including the electrode pad.

Light emitting diodes, abbreviated as LEDs, are semiconductors that emit untuned narrowband light when the forward electricity of the P-N junction is biased. This effect is a form of lightning.

Light emitting diodes are commonly used as small indicators in electronic devices, but they are also used in high power applications such as flash and local lighting.

Such light emitting diodes are usually used in package form with several other components. The LED package may be classified into a top view method and a side view method according to its use. The latter is commonly used as the backlight for small portable devices such as mobile phones and laptops.

The light emitting diode package usually consists of a housing and a lead frame. The housing may comprise a front part and a rear part and a lead frame is located between this front part and the rear part. A light emitting diode chip is mounted on an electrode pad of the lead frame, and the light emitting diode chip receives light from an external power source to generate light. A cavity is formed in the center of the front portion of the housing, and light generated by the LED chip may be emitted to the outside through the cavity.

1 is a cross-sectional view of an electrode pad in which a conventional LED chip is mounted. As shown in FIG. 1, the conventional electrode pad is formed in a structure in which a nickel layer and a silver layer are sequentially stacked on a base layer made of a copper alloy.

This lamination is performed by various methods such as chemical vapor deposition, metal sputtering, electroplating, and electroless metal plating.

In this case, the nickel layer serves to prevent corrosion or oxidation of the base layer, which is a conductive layer located below, to strengthen the bonding force between the base layer and the silver layer disposed thereon, and to increase the light reflectance of the silver layer.

The silver layer laminated on the nickel layer is formed by plating silver particles on the nickel layer and serves to reflect light generated from the light emitting diode chip toward the silver layer to the outside.

The silver layer has an advantage that oxidation does not occur easily even when it is in contact with air, but has a disadvantage that it is easily discolored when contacted with sulfur or hydrogen sulfide in the air. As a result, the light reflectance of the silver layer is significantly reduced and the light efficiency of the light emitting diode package is thus significantly reduced.

Accordingly, there is a need to provide a light emitting diode package capable of preventing a decrease in light efficiency of the light emitting diode package due to discoloration of the silver layer.

In accordance with an embodiment of the present invention comprises a copper alloy layer, a nickel layer, and an antireflection prevention layer sequentially stacked, the antireflection prevention layer is ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os) ), An electrode pad formed of at least one selected from the group consisting of iridium (Ir), platinum (Pt), and alloys thereof.

A silver layer may be further included between the nickel layer and the antireflection prevention layer.

According to an embodiment of the present invention, there is provided a light emitting diode package including a lead frame including an electrode pad on which a light emitting diode chip is mounted, and a housing surrounding the lead frame, wherein the electrode pad is sequentially formed of a copper alloy layer and nickel. Layer, and an anti-reflective layer, wherein the anti-reflective layer includes ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), and alloys thereof Provided is a light emitting diode package formed of at least one selected from the group to be described.

As described above, according to the LED package according to the embodiment of the present invention, a metal layer made of at least one metal selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, and alloys thereof on an electrode pad The stack may be prevented from lowering the light reflectance of the LED package.

Hereinafter, the same reference numerals will be described in detail with reference to the accompanying drawings, with reference to the same components preferred embodiments of the present invention. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

The embodiments described in the specification and the configuration shown in the drawings are preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, various equivalents and modifications that can be substituted for them at the time of the present application are There may be.

2 is a perspective view of a light emitting diode package according to an embodiment of the present invention configured as a side view type.

Referring to FIG. 2, the LED package includes a housing 1 and a lead frame 2. The housing 1 has a front portion 11 and a rear portion 12 are integrally formed. The front portion 11 is formed with a cavity 13 and the cavity 13 is filled with a transparent resin to form a light emitting portion for emitting light generated from the light emitting diode chip.

The lead frame 2 is disposed between the front portion 11 and the rear portion 12. The lead frame 2 includes an electrode pad 21 exposed to the outside through the cavity 13 and mounted with a light emitting diode chip, and an electrode lead 14 extending from the electrode pad 21 to the outside of the housing 1. do.

The housing 1 consisting of the front part 11 and the rear part 12 forms a body of a light emitting diode package and a lower surface of the housing 1 is mounted on a (not shown) substrate and supported by the substrate.

The electrode pad 21 may supply an electric signal from an external circuit (not shown) to the light emitting diode chip to cause light emission. In addition, the electrode pad 21 may reflect light, which is generated from the light emitting diode chip and is directed in the direction of the electrode pad 21, not in the light emitting direction.

An internal structure of the electrode pad 21 will be described in detail with reference to FIG. 3.

3 is a cross-sectional view of an electrode pad on which a light emitting diode chip according to an embodiment of the present invention is mounted.

Referring to FIG. 3, the electrode pad 21 includes a copper alloy layer 10 as a base layer, a nickel layer 20 stacked on the copper alloy layer 10, a silver layer 30 stacked on the nickel layer, And an antireflection prevention layer 40 stacked on the silver layer.

Such lamination may be performed by various methods such as chemical vapor deposition, metal sputtering, electroplating, and electroless metal plating.

The copper alloy layer 10 forms a base layer of an electrode pad and extends outside the housing of the LED package to be connected to an external circuit (not shown) to receive an electrical or electrical signal.

The nickel layer 20 prevents corrosion or oxidation of the copper alloy layer 10 positioned below and enhances the bonding force between the copper alloy layer 10 and the silver layer 30 disposed thereon, and further, the silver layer 30. ) Can help improve the light reflectivity of the light.

The silver layer 30 is formed by plating silver particles on the nickel layer 20 and serves to reflect light generated from the light emitting diode chip toward the silver layer to the outside.

The anti-reflection prevention layer 40 prevents discoloration of the silver layer 30 to prevent the light reflectivity of the silver layer 30 from being lowered, and efficiently has light from the light emitting diode chip having high light reflectivity to the outside. Can be reflected.

In detail, the anti-reflection prevention layer 40 is formed of a metal resistant to discoloration due to oxidation by air and other external influences. As the metal constituting the anti-reflection prevention layer 40, platinum group elements, that is, ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), and alloys thereof At least one may be selected from the group including.

The platinum group elements are well tolerated in high temperature or corrosive environments, and do not oxidize in air or water and are insoluble in acids. In addition, it is generally white and has excellent reflectance.

The antireflection prevention layer 40 may be stacked on the silver layer 30 to prevent the silver layer 30 from being discolored by contact with sulfur compounds such as sulfur or hydrogen sulfide in the air. Therefore, the light emitted from the light emitting diode chip can be efficiently reflected to the outside.

4 is a cross-sectional view of an electrode pad on which a light emitting diode chip according to another embodiment of the present invention is mounted.

Referring to FIG. 4, the electrode pad 21 is missing a silver layer unlike the above-described embodiment described with reference to FIG. 2. As described above, the platinum group element also has a high light reflectance of white and a nickel layer 20 is formed thereunder to assist the improvement of the light reflectivity. Therefore, even if the silver layer 30 is omitted, the reflectance of light generated from the light emitting diode chip is reduced. You can keep it to some extent.

Figure 5a is a graph showing the results of the light efficiency test of the LED package over time according to an embodiment of the present invention and Figure 5b is a table showing the numerical results of the light efficiency test.

Referring to FIG. 5A, a test result of light efficiency of light emitted from a LED package over time is shown. Here, the x axis represents time and the y axis represents light efficiency of the LED package.

In addition, a is a test result using a conventional electrode pad and b is a test result using an electrode pad according to an embodiment of the present invention.

In this test, a side view light emitting diode package was used, and the electrode pad 21 was formed on the electrode pad 21 according to the first embodiment, that is, the nickel layer 20 and the silver layer 30 on the copper alloy layer 10. ) And an electrode pad 21 in which the antireflection prevention layer 40 is sequentially formed, and palladium (Pd) was used as a material of the antireflection prevention layer 40.

The test results were obtained by continuously supplying 60 ° C., 90% humidity, and 25 mA of current for 1200 hours.

As shown in FIG. 5A, a conventional electrode pad including only a copper alloy layer 10, a nickel layer 20, and a silver layer 30 may be applied to the package from the start of the test to about 500 hours as time passes. Although there is no decrease in light efficiency, thereafter, a decrease in light efficiency is remarkable with time.

This is because the silver layer 30 is exposed to sulfur or sulfur compounds in the air as time passes and the color of the silver layer 30 is gradually changed from silver to darker color, thereby reducing light reflectance.

On the contrary, as shown in b of FIG. 4A, it can be seen that the LED package employing the electrode pad according to the exemplary embodiment of the present invention hardly exhibits a decrease in light efficiency over time.

Referring to FIG. 5B, the light efficiency of the light emitting diode package using the conventional electrode pad and the light emitting diode package according to the embodiment of the present invention is started to supply 25 mA of current to the light emitting diode chip for 480 hours. After and after 1000 hours have elapsed the results are shown.

After 480 hours, the average light efficiency, the maximum light efficiency, and the minimum light efficiency of the LED package using the conventional electrode pad were measured to be 0.51%, 5.01%, and -0.93%, respectively. In the case of the LED package using the electrode pad according to an embodiment, the average light efficiency, the maximum light efficiency, and the minimum light efficiency were respectively measured to 0.79%, 1.52%, and 0.14%. Comparing the two results, it can be seen that the light efficiency was not significantly reduced until both 480 hours.

However, in the measurement result after 1000 hours, the average light efficiency, the maximum light efficiency, and the minimum light efficiency of the LED package using the conventional electrode pad were measured to be -9.75%, -4.54%, and -13.07%, respectively. In the case of a light emitting diode package using an electrode pad according to an embodiment of the present invention, the average light efficiency, the maximum light efficiency, and the minimum light efficiency are measured to be -0.48%, 1.25%, and -2.45%, respectively. While the light efficiency of the diode package is significantly reduced, it can be seen that the light efficiency of the light emitting diode package using the electrode pad according to the embodiment of the present invention is almost the same as the result measured after 480 hours.

As described above, according to the LED package using the electrode pad according to the embodiment of the present invention, the discoloration of the silver layer 30 may be prevented, thereby effectively preventing the luminous efficiency of the package from being lowered.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is only illustrative of the preferred embodiments of the present invention and is not intended to limit the present invention. In addition, it is a matter of course that various modifications and variations are possible without departing from the scope of the technical idea of the present invention by anyone having ordinary skill in the art.

1 is a cross-sectional view of an electrode pad on which a light emitting diode chip according to the prior art is mounted;

2 is a perspective view of a light emitting diode package according to an embodiment of the present invention;

3 is a cross-sectional view of an electrode pad on which a light emitting diode chip is mounted according to an embodiment of the present invention;

4 is a cross-sectional view of an electrode pad mounted with a light emitting diode chip according to another embodiment of the present invention; and

Figure 5a is a graph showing the results of the light efficiency test of the LED package over time according to an embodiment of the present invention and Figure 5b is a table showing the light efficiency test results numerically.

Claims (4)

A copper alloy layer, a nickel layer, and an antireflection prevention layer laminated sequentially, the antireflection prevention layer is ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt) and at least one selected from the group consisting of alloys thereof. The electrode pad of claim 1, further comprising a silver layer between the nickel layer and the antireflective layer. A light emitting diode package comprising a lead frame including an electrode pad on which a light emitting diode chip is mounted, and a housing surrounding the lead frame. The electrode pad includes a copper alloy layer, a nickel layer, and an antireflection prevention layer sequentially stacked, and the antireflection prevention layers include ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), and iridium ( Ir), platinum (Pt), and a light emitting diode package, characterized in that formed at least one selected from the group consisting of alloys thereof. The light emitting diode package of claim 3, further comprising a silver layer between the nickel layer and the antireflective layer.

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