WO2015109580A1

WO2015109580A1 - Led encapsulation method

Info

Publication number: WO2015109580A1
Application number: PCT/CN2014/071512
Authority: WO
Inventors: 裴小明; 曹宇星
Original assignee: 上海瑞丰光电子有限公司
Priority date: 2014-01-26
Filing date: 2014-01-26
Publication date: 2015-07-30

Abstract

An LED encapsulation method, comprising: manufacturing a transparent encapsulation film (1) or transparent glass sheet having recesses (11) in an array arrangement; filling the recesses (11) with fluorescent glue (3), wherein the amount of fluorescent glue filled into each recess (11) is a difference between the volume of the recess (11) and the volume of a flip chip (2) to be encapsulated; fixing the flip chip (2) into the fluorescent glue (3), and exposing a bottom electrode (21) of the flip chip (2) to form LED encapsulation sheets in an array arrangement; and dividing the LED encapsulation sheets in the array arrangement into a plurality of LED encapsulation monomers. According to the method, encapsulation of the flip chip (2) on the transparent encapsulation film (1) or transparent glass sheet is performed, the encapsulation body is only constituted by the flip chip (2), the fluorescent glue (3) and the transparent encapsulation film (1), and thus has the advantages of high reliability, saving materials, low cost and high productivity; no restrictions on the shape of a bracket facilitates large-scale integrated encapsulation; not having to separate the fluorescent glue reduces the manufacturing processing; losses such as interior scattering of photons in fluorescent powder can be reduced to facilitate improving product brightness; and not having to plate a gold-tin alloy layer on positive and negative electrodes of the chip saves cost.

Description

LED packaging method

Technical field

The present invention relates to the field of LED product manufacturing technology, and in particular, to an LED packaging method.

Background technique

The traditional white LED product is packaged by fixing the LED chip to the cup on the holder by means of solid bonding or eutectic soldering. The positive electrode of the wafer is connected to the positive electrode of the holder by a gold wire, and the negative electrode of the wafer is connected. At the negative electrode of the stent, the bowl is filled with a fluorescent gel that matches the target color region. Since the thermal expansion coefficients of the stent, the fluorescent glue, and the colloid for bonding the wafer are different, it is easy to have reliability problems in the bracket, the fluorescent glue, the gold wire, the colloid, etc.; and the LED bracket has various types, and the bonding wafer and the bracket have positive and negative electrodes. Most of the materials are PPA, PCT and EMC materials, which have high defects in high temperature resistance and air tightness, which in turn affects the reliability of LED products. Although the ceramic bracket has better high temperature resistance and better air tightness, the cost of the bracket is close to the cost of the wafer, and the cost of the ceramic bracket package LED is expensive, and the equipment investment is large, resulting in a small production capacity and high price of the ceramic bracket LED product. Therefore, the defects in reliability, service life, manufacturing cost and price of LED products with bracket package structure are the major obstacles for LED products to replace traditional lighting products.

technical problem

The object of the present invention is to provide an LED packaging method, which aims to improve the reliability of an LED product, ensure its long service life, and at the same time reduce costs and increase productivity.

Technical solution

The present invention is achieved by the LED packaging method comprising the following steps:

Making a transparent encapsulating film or a transparent glass sheet having an array of pockets;

Filling the cavity with fluorescent glue, the amount of fluorescent glue filled in each cavity is the difference between the volume of the cavity and the volume of the flip chip to be packaged;

Fixing the flip chip in the fluorescent glue, exposing the bottom electrode of the flip chip, and immersing the other surface in the fluorescent glue to form a whole array of LED package sheets;

The arrayed LED package sheet is divided into a plurality of LED package monomers.

Beneficial effect

Compared with the conventional method of using the stent package, the invention has the following advantages:

First, the LED package monomer produced by the method is composed only of the flip chip 2, the fluorescent glue 3, and the transparent encapsulant 1 , and the material such as the bracket and the gold wire is omitted, and the flip chip 2, the fluorescent glue 3 and the transparent encapsulant are omitted. 1The performance is extremely stable, the reliability is much higher than the package mode of the bracket and the gold wire, thereby avoiding the product reliability problem caused by the different thermal expansion coefficients of the bracket and the colloid, ensuring its long service life and saving a lot of cost. To increase production capacity;

Secondly, the transparent encapsulant or the transparent glass is used as the working substrate, and the packaging worktable is not needed, and the operation is convenient; the recess 11 is directly formed on the transparent encapsulant 1 or the plexiglass, and the fluorescent glue 3 is filled into the recess 11 Directly forming an independent fluorescent glue layer, omitting the process of separating the fluorescent glue compared with the method of coating the fluorescent glue on the wafer and then separating the fluorescent glue, thereby greatly simplifying the process;

Third, the packaging process is directly performed on the transparent packaging film or the transparent glass, which is easy to operate, and has higher material utilization rate and lowers the packaging cost compared with the method of using the dispensing machine to glue a little bit in the cup;

Fourth, the limitation of the shape without the bracket, the packaging process is simpler, and the large-scale integrated packaging of the LED product is favorable, which is advantageous for reducing the cost of the packaged device;

Fifth, since the cup-and-cup package is not used, the loss of internal scattering of photons between the phosphors is greatly reduced, which is advantageous for improving the brightness of the product;

Sixth, since the wafer is not supported by the support, the anode and the cathode of the flip chip do not need an expensive gold-tin alloy layer of a certain thickness (about 3 μm) (the conventional method requires a gold-tin alloy layer to be soldered on the support at the bottom of the wafer), Save costs.

DRAWINGS

1 is a flow chart of an LED packaging method according to a first embodiment of the present invention;

2a is a schematic diagram of a package structure corresponding to the LED packaging method (1);

2b is a schematic diagram of a package structure corresponding to the LED packaging method (2);

2c is a schematic diagram of a package structure corresponding to the LED packaging method (3);

2d is a schematic diagram of a package structure corresponding to the LED packaging method (4);

2e is a schematic diagram of a package structure corresponding to the LED packaging method (5);

Figure 2f is an enlarged view of the area A in Figure 2e;

Figure 2g is a schematic diagram of a package structure corresponding to the LED packaging method (six);

Figure 2h is a schematic diagram of a package structure corresponding to the LED packaging method (7);

2i is a schematic diagram of a package structure corresponding to the LED packaging method (8);

2j is a schematic structural view of an LED package unit obtained by an LED packaging method (1);

2k is a schematic structural view (II) of an LED package unit obtained by an LED packaging method.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

1 is a flow chart of a method for packaging an LED according to an embodiment of the present invention, and FIGS. 2a to 2i are diagrams showing a product package structure corresponding to the method. For convenience of description, only parts related to the embodiment are shown. .

With reference to FIG. 1 , an LED packaging method provided by an embodiment of the present invention includes the following steps:

Step S101, manufacturing a transparent package film 1 or a transparent glass sheet having the array 11 of the arrays;

In this embodiment, the transparent encapsulating film 1 or the transparent glass sheet is used as the outermost package structure of the packaged LED wafer, and the recess 11 is used for filling the fluorescent glue and placing the LED flip chip 2, the shape and the coverage of the recess 11. The shape of the crystal wafer 2 is matched, and the back surface of the transparent encapsulating film 1 or the transparent glass sheet is a flat surface or a lens array, wherein the lens 12 is in one-to-one correspondence with the recesses 11, as shown in Figs. 2a and 2b.

Step S102, filling the cavity with fluorescent glue, the amount of fluorescent glue filled in each cavity is the difference between the volume of the cavity and the volume of the flip chip to be packaged; as shown in Figures 2c and 2d;

Step S103, the flip chip is fixed in the fluorescent glue, and the bottom electrode of the flip chip is exposed, and the other surfaces are immersed in the fluorescent glue to form a whole array of LED package sheets; as shown in FIG. 2e, 2f, 2g;

By precisely controlling the amount of fluorescent glue, the bottom electrode 21 of the flip chip 2 can be exposed, and the other five surfaces are immersed in the fluorescent glue 3. Further, the depth of the recess 11 can be appropriately set so that the thickness of the fluorescent paste 3 directly above the flip chip 2 is 30 to 500 μm.

Step S104, dividing the array LED package sheet into a plurality of LED package monomers; as shown in FIG. 2h and FIG. 2i.

After the steps S101 to S104, the LED package unit shown in FIG. 2j or FIG. 2k can be obtained. Each LED package unit includes a flip chip 2, and the periphery of the flip chip 2 is coated with a fluorescent glue 3, A transparent encapsulant 1 is disposed outside the fluorescent paste 3, and the bottom electrode 21 of the flip chip 2 is exposed for soldering to the electrodes of the application end.

Further, a solder resist may be filled between the positive and negative electrodes at the bottom of the flip chip 2 to prevent the electrode from being short-circuited at the application end.

Secondly, the transparent encapsulant or the transparent glass is used as the working substrate, and the packaging worktable is not needed, and the operation is convenient; the recess 11 is directly formed on the transparent encapsulant 1 or the transparent glass, and the fluorescent glue 3 is filled into the recess 11 Directly forming an independent fluorescent glue layer, omitting the process of separating the fluorescent glue compared with the method of coating the fluorescent glue on the wafer and then separating the fluorescent glue, thereby greatly simplifying the process;

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

The LED chip packaging method is characterized in that it comprises the following steps:

Making a transparent encapsulating film or a transparent glass sheet having an array of pockets;

Filling the cavity with fluorescent glue, the amount of fluorescent glue filled in each cavity is the difference between the volume of the cavity and the volume of the flip chip to be packaged;

Fixing the flip chip in the fluorescent glue, exposing the bottom electrode of the flip chip, and immersing the other surface in the fluorescent glue to form a whole array of LED package sheets;

The arrayed LED package sheet is divided into a plurality of LED package monomers.
The method of packaging of claim 1 wherein the shape of the recess coincides with the shape of the flip chip.
The packaging method according to claim 1, wherein the back surface of the transparent package film or the transparent glass sheet is a flat surface.
The packaging method according to claim 1, wherein the back surface of the transparent package film or the transparent glass sheet is a lens array, wherein each lens has a one-to-one correspondence with the pockets.
The packaging method according to claim 1, wherein the phosphor paste directly above the flip chip has a thickness of 30 to 500 μm.