Method for inspecting package of light emission diode

Abstract

To provide a method for inspecting an innovative package of a light emission diode.SOLUTION: The present invention relates to a method for inspecting a package 100 of a light emission diode. The method for inspection includes the step of providing a package 100 of a light emission diode. The package 100 of the light emission diode includes a light emission diode element 110, a frame 120, and a sealing material 130. The light emission diode element 110 is arranged on the frame 120. The frame 120 is higher than the light emission diode element 110. The sealing material 130 covers a part of the light emission diode element 110 and the frame 120. The method for inspection includes a step of removing a part of the sealing material 130 and exposing the upper surface of the light emission diode element 110.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for inspecting a light emitting diode package, and more particularly to a method for inspecting a cross section of a light emitting diode package. [Background technology]

[0002] Light-emitting diodes have advantages such as small size, long life, energy saving, and high efficiency, and are widely used in fields such as lighting and displays. Light-emitting diodes have a variety of package structures. Common bullet-type light-emitting diodes (lamp LEDs) include 3mm, 5mm, round, concave, oval, and square types, and are widely used in consumer products, home appliances, traffic signals, outdoor displays, industrial equipment, etc.

[0003] 1 shows a typical bullet-type light-emitting diode package. This type of bullet-type light-emitting diode package 1 basically includes a light-emitting diode element 10, a frame 20, and an encapsulant 30. The light-emitting diode element 10 is fixed on the frame 20. The frame 20 has two independent electrodes electrically connected to the anode and cathode of the light-emitting diode element 10, respectively. The encapsulant 30 covers the light-emitting diode element 10 and a part of the frame 20.

[0004] In order to effectively control the production quality of LED packages, package failure analysis is required. A common analysis method is to use grinding and ion beam cutting to cut the LED package down to the LED element, exposing the cross section of the components inside the LED package. By analyzing the cross section, the defective state of the components inside the package and its cause can be found, and a product improvement plan can be proposed.

[0005] However, after grinding the light-emitting diode package, a phenomenon that components separate within the package often occurs. As shown in FIG. 2, cracks occur between the encapsulant 30 and the frame 20, between the silver adhesive 40 and the frame 20, and between the silver adhesive 40 and the light-emitting diode element 10. However, with the current inspection method, there is no way to know whether the cracks are due to an abnormality in the manufacturing process of the light-emitting diode package or an abnormality in the grinding process. As a result, this has a negative impact on the subsequent judgment of quality abnormalities.

[0006] In order to overcome the above problems, it has become an urgent task in the industry to develop an innovative inspection method that can reduce unintended cracks in packages caused by improper grinding, accurately identify the causes of abnormalities in the package manufacturing process, and suppress the negative impact of cracks caused by improper grinding on abnormality judgment in the inspection process. Summary of the Invention

[0007] The main objective of the present invention is to provide an innovative method for inspecting LED packages, which can reduce unintended cracks in the packages caused by improper grinding and suppress the adverse effect of cracks caused by improper grinding on abnormality judgment in the inspection process, thereby making it possible to accurately determine the cause of abnormalities in the package manufacturing process.

[0008] In order to achieve the above object, the present invention provides a method for inspecting a light emitting diode package. The inspection method includes the step of providing a light emitting diode package. The light emitting diode package includes a light emitting diode element, a frame, and an encapsulant. The light emitting diode element is disposed on the frame. The height of the frame is greater than the height of the light emitting diode element. The encapsulant covers the light emitting diode element and a portion of the frame. Next, the inspection method includes the step of removing a portion of the encapsulant to expose an upper surface of the light emitting diode element.

[0009] In an embodiment of the present invention, the method for inspecting a light emitting diode package further includes removing a part of the encapsulant on a side surface of the light emitting diode element.

[0010] In an embodiment of the present invention, the method for inspecting a light emitting diode package further includes ion-polishing the light emitting diode element with an ion beam to form a cross section of the light emitting diode package.

[0011] In an embodiment of the present invention, the step of removing a portion of the encapsulant to expose the top surface of the light-emitting diode element comprises removing the portion of the encapsulant from the top surface of the light-emitting diode element by grinding with a grinding wheel.

[0012] In an embodiment of the present invention, the step of removing a portion of the encapsulant on the side surface of the light-emitting diode element comprises removing a portion of the encapsulant from the side surface of the light-emitting diode element by grinding with a grinding wheel.

[0013] In an embodiment of the present invention, the light emitting diode package further comprises a conductive adhesive for fixing the light emitting diode element to the frame.

[0014] In an embodiment of the present invention, the light emitting diode device is a horizontal type light emitting diode device or a vertical type light emitting diode device.

[0015] Those skilled in the art can understand other objects of the present invention, as well as the technical means and embodiments of the present invention, by referring to the drawings and the embodiments described below. [Brief description of the drawings]

[0016] [Figure 1] Schematic diagram showing the package structure of a conventional bullet-type light-emitting diode [Diagram 2] SEM photo showing the cross section of a conventional bullet-type light-emitting diode package after grinding [Diagram 3]FIG. 1 is a schematic diagram showing a part of a package of a bullet-type light-emitting diode to be inspected in the inspection method according to an embodiment of the present invention; [Figure 4] FIG. 1 is a partial top view showing a bullet-type light-emitting diode package in a testing method according to an embodiment of the present invention; [Diagram 5] SEM photograph showing a cross section of a package after cutting in the inspection method according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The contents of the present invention will be described below through examples. The examples of the present invention are examples of embodiments, and are not intended to limit the present invention to the environments, applications, or specific aspects described in the examples. Therefore, the explanation of the examples is for explaining the present invention, but does not limit the present invention. In the embodiments and drawings, components that are not directly related to the present invention are omitted and not shown. The dimensional relationship between the components in the drawings is for ease of understanding, and does not limit the actual dimensions.

[0018] FIG. 3 is a schematic diagram showing a part of a bullet-type light-emitting diode package to be inspected in the inspection method according to the embodiment of the present invention. The bullet-type light-emitting diode package 100 shown in the figure has the same structure as a conventional light-emitting diode package, and basically includes a light-emitting diode element 110, a frame 120, an encapsulant 130, and a conductive adhesive 140. The light-emitting diode element 110 is a general horizontal light-emitting diode element or a vertical light-emitting diode. In the embodiment of the present invention, the light-emitting diode element 110 has a vertical structure. In addition, the frame 120 has two independent electrodes, that is, an anode electrode 122 and a cathode electrode 124. The upper half of the cathode electrode 124 has a concave cup structure that is wide at the top and narrow at the bottom. The heights of the anode electrode 122 and the cathode electrode 124 of the frame 120 are both higher than the height of the light-emitting diode element 110, so that the light-emitting diode element 110 can be accommodated therein. The light emitting diode element 110 is adhered to an end surface of the cathode electrode 124 by a conductive adhesive 140 such as a silver adhesive, and is electrically connected. In particular, the anode electrode 122 of the frame 120 is electrically connected to an upper electrode of the light emitting diode element 110. The cathode electrode 124 of the frame 120 is electrically connected to a lower electrode on the back surface of the light emitting diode element 110. The sealing material 130 covers the entire light emitting diode element 110, the conductive adhesive 140, and a part of the frame 120. The sealing material 130 may be an epoxy resin.

[0019] The present invention uses finite element analysis to investigate the stress distribution between the light-emitting diode element, conductive adhesive, frame, and encapsulant in a conventional light-emitting diode package structure. It is found that the bottom of the light-emitting diode element is the location where the greatest stress is applied. When grinding with a cross-section polisher as in the conventional inspection method, stress is improperly transmitted to the package structure, and the encapsulant expands so that the light-emitting diode element floats up, resulting in unexpected separation between the encapsulant and the frame, the conductive adhesive and the frame, and the conductive adhesive and the element. In view of the above circumstances, the present invention proposes an innovative inspection method that can reduce unexpected cracks caused by improper transmission of stress during grinding.

[0020] As shown in FIG. 3, in order to reduce inappropriate transfer of stress to the inside of the package structure during grinding, the inspection method of the present invention performs grinding in stages. Specifically, first, a part of the encapsulant 130 in the upper half of the package 100 is removed by grinding with a grinding wheel from the top of the light-emitting diode package 100. For example, a part of the encapsulant is removed from the top of the light-emitting diode element 110 until the top of the light-emitting diode element 110 is exposed. As shown in FIG. 3, the line segment A-A' is the top grinding end line of the first stage grinding. After grinding, no encapsulant remains on the top of the light-emitting diode element 110. In a preferred embodiment, the first stage grinding can be further divided into two stages. First, a part of the encapsulant 130 is removed from the top of the light-emitting diode package 100 to the outside of the frame 120 by grinding with a coarse grinding wheel. Next, a part of the encapsulant 130 between the frame 120 and the light-emitting diode element 110 is removed by grinding with a fine grinding wheel until the top of the light-emitting diode element 110 is exposed.

[0021] Next, a description will be given with reference to FIG. 4. FIG. 4 is a partial top view showing the light-emitting diode element 110, the frame 120, and the encapsulant 130 in the light-emitting diode package 100. The outer shape and dimensional ratio of each component shown in FIG. 4 are for explanation only and do not show the actual outer shape and dimensional ratio of the package. In a preferred embodiment, after removing a part of the encapsulant 130 on the upper part of the light-emitting diode package 100, the side surface of the light-emitting diode package 100 is ground with a grinding wheel device to remove a part of the encapsulant from the side surface of the light-emitting diode element 100. As shown in FIG. 4, the line segment B-B' is the side surface grinding end line of the second stage grinding. In this stage of grinding, the part outside the side surface of the light-emitting diode element 110 is ground, but the side surface of the light-emitting diode element 110 is not exposed.

[0022] Next, a third grinding step is performed. In this grinding step, the light emitting diode package 100 is polished with an ion beam using a cross-section grinding device. As shown in Fig. 4, the package 100 is polished with an ion beam from line segment B-B' to line segment C-C' until a cross-section of the light emitting diode package is formed. Fig. 5 is a SEM (scanning electron microscope) photograph showing a cross-section of the light emitting diode package after using the light emitting diode package inspection method according to the present invention.

[0023] As shown in FIG. 5, since the cross-section grinding process is divided into a plurality of different grinding stages, the stress generated in the grinding process is effectively released step by step without being transferred to the components in the package, and the adverse effect of the stress on the light-emitting diode element and other components is greatly reduced. In particular, since the encapsulant between the top of the package and the surface of the element is almost removed in the first stage, the stress caused by grinding does not substantially affect the durability of the components in the package in the subsequent grinding process. Therefore, the light-emitting diode element 110, the frame 120, the encapsulant 130, and the conductive adhesive 140 in the light-emitting diode package 100 can still maintain good structural integrity, and no unexpected separation phenomenon such as cracks occurs between the elements. This allows the cause of the abnormality in the manufacturing process to be accurately identified in the subsequent analysis and judgment of the product abnormality, and more accurate inspection is possible.

[0024] The above examples are for explaining the embodiments of the present invention and for explaining the characteristic configuration of the present invention. The present invention is not limited to the above examples. Modifications or equivalent arrangements that can be easily made by those skilled in the art are also within the scope of the present invention. The scope of protection of the rights of the present invention is based on the claims. [Explanation of symbols]

[0025] 1 Light Emitting Diode Package 10 Light emitting diode element 20 Frames 30 Encapsulating material 40 Conductive Adhesive 100 Light Emitting Diode Packages 110 Light emitting diode element 120 frames 122 Anode Electrode 124 Cathode Electrode 130 Encapsulating material 140 Conductive adhesive

Claims

1. A method for inspecting a light emitting diode package, comprising the steps of: the light-emitting diode package includes a light-emitting diode element, a frame, and a sealing material, the light-emitting diode element is disposed on the frame, the height of the frame is greater than the height of the light-emitting diode element, and the sealing material covers the light-emitting diode element and a part of the frame; The inspection method includes: providing a package for the light emitting diode; and removing a portion of the encapsulant to expose an upper surface of the light emitting diode element.

2. 2. The method for inspecting a light emitting diode package according to claim 1, further comprising the step of removing a part of the encapsulant on a side surface of the light emitting diode element.

3. 3. The method of claim 2, further comprising the step of polishing the light emitting diode element with an ion beam to form a cross section of the light emitting diode package.

4. 2. The method for inspecting a light-emitting diode package according to claim 1, wherein the step of removing a portion of the encapsulant to expose the top surface of the light-emitting diode element comprises removing a portion of the encapsulant from the top surface of the light-emitting diode element by grinding with a grinding wheel.

5. 3. The method for inspecting a light-emitting diode package according to claim 2, wherein the step of removing a portion of the encapsulant from the side surface of the light-emitting diode element comprises removing a portion of the encapsulant from the side surface of the light-emitting diode element by grinding with a grinding wheel.

6. 2. The method of claim 1, wherein the light emitting diode package further comprises a conductive adhesive for fixing the light emitting diode element to the frame.

7. 2. The method of claim 1, wherein the light emitting diode element is a horizontal type light emitting diode element or a vertical type light emitting diode element.

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