KR20110119909A - Method for manufacturing led package - Google Patents

Abstract

PURPOSE: A light emitting diode package manufacturing method is provided to perform a wire bonding process after coating a fluorescent substance on a light emitting diode chip, thereby arranging a uniform fluorescent coating layer on the light emitting diode chip. CONSTITUTION: An electrode pad(20a) is arranged in the upper surface of a light emitting diode chip(20). The light emitting diode chip is mounted on a lead frame(10). A fluorescent substance film(40) is arranged by applying a fluorescent substance on the light emitting diode chip. The electrode pad is exposed by eliminating a part of the fluorescent substance film corresponding to the electrode pad by laser etching. A first electrode, second electrode, and electrode pad surface are bonded with a wire(50).

Description

Light emitting diode package manufacturing method {Method for manufacturing LED package}

The present invention relates to a light emitting diode package manufacturing method, and more particularly to a light emitting diode package manufacturing method for uniformly coating a phosphor on the light emitting surface of the light emitting diode chip.

A light emitting diode (LED) refers to a device that makes a small number of carriers (electrons or holes) injected using a pn junction structure of a semiconductor and emits a predetermined light by recombination thereof, and red using GaAsP or the like. Green light emitting diodes using light emitting diodes, GaP and the like, and blue light emitting diodes using InGaN / AlGaN double hetero structure.

The light emitting diode has a low power consumption, a long service life, can be installed in a narrow space, and provides a strong vibration resistance characteristic. Such light emitting diodes are used as display devices and backlights, and active research is being conducted to apply them to general lighting applications. Recently, white light emitting diodes have been introduced in addition to single color components, for example, red, blue, or green light emitting diodes. As white light emitting diodes are applied to automotive and lighting products, the demand is expected to increase rapidly.

White light emitting diode technology can be divided into two ways.

First, red, green, and blue light emitting diode chips are installed adjacent to each other, and the light emission of each device is mixed to realize white color. However, since each LED chip has different thermal or temporal characteristics, there is a problem in that the color tone is changed according to the use environment, and in particular, color uniformity is not realized.

Secondly, the phosphor is disposed on the light emitting diode chip, so that a part of the first light emission of the light emitting diode chip and the secondary light emission wavelength-converted by the phosphor are mixed to realize white color. For example, a phosphor emitting yellow green or yellow light as a source of excitation as part of an excitation source on a light emitting diode chip emitting blue light can be distributed to obtain white color by blue light emission of the light emitting diode chip and yellow green light or yellow light emission of the phosphor. Currently, a method of implementing white light using a blue light emitting diode chip and a phosphor has been popularized.

1 is a cross-sectional view of a light emitting diode package manufactured according to this manufacturing method.

Referring to the drawings, the LED package 1000 includes a lead frame 100 and a light emitting diode chip 300 mounted on a bottom surface of the cavity 200 formed in the lead frame 100.

In the general method of manufacturing the LED package 1000, the LED chip 300 is mounted on the bottom surface of the cavity 200, and then the electrode pad and the electrode 500 on the top surface of the LED chip 300 are bonded to the wire 400. The phosphor 700 is applied to the inside of the cavity 200.

At this time, the phosphor 700 is not directly applied, but is injected into the encapsulant 600 containing the resin. The resin protects the light emitting diode chip 300 while not directly affecting light generated from the light emitting diode chip 300, and the phosphor 600 absorbs light generated from the light emitting diode chip 300. It generates light of a different wavelength from the absorbed light. When the resin is cured, the LED package 1000 is completed.

The method of manufacturing the light emitting diode package 1000 has the following problems.

First, the phosphor 700 dispersed in the resin is precipitated to the bottom by gravity in the curing process of the resin. In this case, as shown in FIG. 1, the phosphor 700 may not be completely applied to the side surface of the LED chip 300. As a result, the light emitted from the side surface of the LED chip 300 is difficult to be converted using the phosphor 700, and thus the color of light emitted through the LED packager 10000 is not uniform. In addition, uniform coating may not be achieved due to agglomeration of the phosphors 700, and an uneven mixing phenomenon of the phosphors 700 occurs due to interference of the wire 400 bonding when the phosphors 700 are applied. Get mad.

In addition, when a larger amount of the phosphor 700 is applied to the upper surface of the LED chip 300 to convert the wavelength of light emitted from the side of the LED chip 300, the luminance is reduced due to the excessively large phosphor 700. This causes a problem of low light efficiency.

In order to solve the above problems, Japanese Laid-Open Patent Publication No. 2010-010261 has proposed a method of manufacturing a light emitting diode package by applying a phosphor to a light emitting diode chip and then wire bonding it.

2A is a cross-sectional view of a package in which a phosphor is applied to a light emitting diode chip through screen printing according to the related art, and FIG. 2B is a state in which a reflective resin is applied to the surface of the electrode pad 300a to prevent light leakage after the phosphor coating film is generated. Partial cross section of the.

Referring to the drawings, the prior art processes the electrode pad 300a only on the upper surface of the LED chip 300 by screen printing, and the phosphor 700 is disposed on the remaining light emitting surface except for the electrode pad 300a. Technology to be coated.

When using such a screen printing technique, as shown in the figure, it is difficult to form the phosphor 700 coating layer on the side of the light emitting diode chip 300, and the light leakage occurs in the electrode pad 300a part due to the low precision, so that light conversion is performed. It will not work smoothly. In addition, as shown in FIG. 2B, in order to solve the above problems, light leakage is suppressed by applying the light reflection resin 910 on the electrode pad 300a, but the process according to the application of the light reflection resin 910 is suppressed. The increase in yield yields a problem.

Alternatively, before the wire bonding of the light emitting diode chip 300 in the package manufacturing process, the phosphor 700 is uniformly coated on the light emitting diode chip 300 in advance, and then an electrode is placed on the top of the light emitting diode chip 300 through a photolithography process. A technique of preparing a bonding pad by etching the coating film of the phosphor 700 on the electrode pad 300a by masking the pad 300a to correspond to the pad 300a has been proposed. However, the above-described method has a problem in that the process itself is complicated and the yield is remarkably low, making it difficult to apply the field.

Therefore, there is an increasing demand for solving the problems of the conventional LED package manufacturing method.

The present invention has been made to solve the above problems, an object of the present invention is to provide a light emitting diode package manufacturing method for forming a uniform phosphor coating layer on a light emitting diode chip.

According to an aspect of the present invention for achieving the above object, the step of mounting a light emitting diode chip having an electrode pad on the upper surface on a lead frame provided with a first electrode and a second electrode, applying a phosphor to the light emitting diode chip Forming a phosphor film, exposing the electrode pad by laser etching a portion of the phosphor film corresponding to the electrode pad formed on the upper surface of the light emitting diode chip, and bonding the wire between the first electrode, the second electrode, and the electrode pad surface. Provided is a method of manufacturing a light emitting diode package comprising the steps of:

Here, the phosphor is applied to the entire upper and side surfaces of the light emitting diode chip.

In addition, the coating of the phosphor may be made by a spray injection method.

The exposed electrode pads are laser pretreated by removing the phosphor film corresponding to the electrode pads formed on the upper surface of the light emitting diode chip by laser etching.

According to the present invention as described above, the electrode pad is exposed to the phosphor-coated light emitting diode chip by laser etching, so the etching precision is high, so that the color of light emitted through the package is uniform without a process for preventing additional light leakage, resulting in a high yield. It is highly effective.

In addition, after the phosphor is coated on the LED chip, wire bonding may be performed to form a uniform phosphor coating layer on the LED chip.

1 is a cross-sectional view of a light emitting diode package manufactured according to a general manufacturing method.
2A is a cross-sectional view of a package in which a phosphor is coated on a light emitting diode chip through screen printing according to the proposed technology.
2B is a partial cross-sectional view of a state in which a reflective resin for preventing light leakage is applied to an electrode pad surface after generating a phosphor coating film.
3A to 3D are manufacturing process diagrams of the LED package according to the present invention.
4 is a view showing a blue missing improvement effect of the LED package according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3A to 3D are manufacturing process diagrams of the LED package according to the present invention.

Method of manufacturing a light emitting diode package according to the present invention comprises the steps of mounting a light emitting diode chip 20 having an electrode pad on the upper surface on a lead frame 10 provided with a first electrode (30a) and a second electrode (30b), Forming the phosphor 40 film by applying the phosphor 40 to the light emitting diode chip 20, by removing the phosphor 40 film of the portion corresponding to the electrode pad formed on the top surface of the light emitting diode chip 20 by laser etching Exposing the pad 20a, and bonding the first electrode 30a and the second electrode 30b to the surface of the electrode pad with the wire 50.

Hereinafter, with reference to the drawings will be described in more detail.

3A illustrates a step of preparing a light emitting diode package. First, a light emitting diode chip 20 is mounted on a lead frame 10 provided with a first electrode 30a and a second electrode 30b.

As shown in FIG. 3B, the phosphor 40 containing the resin is coated on the light emitting surface of the LED chip 20 to form a phosphor 40 coating film.

The phosphor 40 is applied to the entire top and side surfaces of the light emitting diode chip 20. In this case, the phosphor 40 may be applied to the light emitting surface of the light emitting diode chip 20 by spray spraying. The spray injection method is sprayed onto the light emitting surface of the LED chip 20 in the form of small particles using a predetermined sprayer, that is, a spray. Particles to be sprayed include a phosphor 40, a resin and a volatile diluent, the diluent of the sprayed particles instantaneously evaporates to form a phosphor 40 coating film, thereby shortening the process time, and also a small amount of phosphor ( 40 alone may be uniformly distributed on the light emitting surface of the LED chip 20 to reduce the amount of the phosphor 40 used.

The spray used herein may be an air jet spray, and the spray angle is adjusted to sufficiently apply particles to the side and edge portions of the light emitting diode chip 20, and the spray time is adjusted to adjust the phosphor 40 to a certain thickness. A coating film is formed.

3C is a diagram illustrating a state in which the electrode pad 20a is exposed by removing the phosphor 40 coating film through laser processing. The etching through the laser processing is more precisely removed than the coating method of the phosphor 40 by screen printing, so that no gap is generated between the electrode pad 20a and the phosphor 40. There is almost no light leakage.

The system for laser processing can be used "LASERTEC" 's "DML80fc" system and "KLS246" laser type. This system has 4 times beam magnification, 100 times magnification of magnification and 0.4 ~ 0.6 mm inner diameter. Having a nozzle, a nozzle clearance of 0.3 to 0.5 mm and a focal length of 3.0 to 4.0 mm.

And before bonding the electrode pad 20a to the wire 50, the electrode pad is pretreated with plasma in order to prevent contamination of the electrode pad metal surface by a pretreatment process and to achieve good electrical bonding.

As shown in FIG. 3D, a constant voltage is applied to the LED chip 20 by bonding the electrode pad, the first electrode 30a, and the second electrode 30b with the wire 50.

In the following, the effect according to the embodiment of the present invention and the experiment of the prior art will be compared and analyzed.

4 is a view showing a blue missing improvement effect of the LED package according to the present invention.

Example 1 is a light emitting diode package according to the present invention, Comparative Example 1 is a conventional light emitting diode package after forming a phosphor coating layer through screen printing, and then coated the bonding portion with a light reflecting resin after wire bonding, Comparative Example 2 After forming the phosphor coating layer through screen printing according to the prior art, the chromaticity of the light emitted from the light emitting surface of the LED package in the wire bonded state is measured.

In Example 1, Comparative Example 1, and Comparative Example 2, the chromaticity of the components and the coating thickness of the phosphor and the configuration of the LED package were measured in the same state. Light emitting diode As a chip, a blue light emitting diode having a length of 980 microns m was mounted, and a phosphor coating layer containing a yellow phosphor was formed to a thickness of 200 microns m. As the phosphor coating layer, a phosphor dispersion obtained by mixing 27 wt% of YAG-based phosphors with respect to silicon-based thermosetting resins and 13 wt% of fumed silica for viscosity adjustment was used.

As a result, in Example 1, no blue missing parts were generated as in Comparative Example 2, and the chromaticity graph was similar to that of Comparative Example 2. In terms of light leakage reduction, it means that the effect is almost equivalent to that of Comparative Example 1.

As described above, in the method of manufacturing the LED package according to the present invention, a uniform phosphor coating film is formed on the light emitting surface of the LED chip by coating the phosphor by spray spraying and then wire bonding. By removing it, light leakage from the electrode pad is suppressed.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the scope of the appended claims should include all such modifications and changes as fall within the scope of the present invention.

10: lead frame 20: light emitting diode chip
20a: electrode pad 30a: first electrode
30b: second electrode 40: phosphor
50: wire

Claims (4)

Mounting a light emitting diode chip having electrode pads formed on an upper surface thereof on a lead frame provided with a first electrode and a second electrode;
Forming a phosphor film by applying a phosphor to a light emitting diode chip;
Exposing the electrode pads by laser etching the phosphor film of the portion corresponding to the electrode pads formed on the upper surface of the LED chip;
A method of manufacturing a light emitting diode package, the method comprising: bonding a wire between a first electrode and a second electrode and an electrode pad surface.
The method of claim 1,
The phosphor is coated on the entire upper surface and side of the light emitting diode chip manufacturing method of the LED package.
The method of claim 1,
The method of manufacturing a light emitting diode package, characterized in that the coating of the phosphor is made by a spray injection method.
The method of claim 1,
A method of manufacturing a light emitting diode package according to claim 1, wherein the exposed electrode pads are plasma pretreated by removing the phosphor film corresponding to the electrode pads formed on the upper surface of the light emitting diode chip by laser etching.

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