CN101295754A - Flip chip bonding packaging structure and method for light emitting diode - Google Patents

Abstract

The invention discloses a flip chip package structure of a light emitting diode, wherein a package base is provided with a recess. The two mutually insulated conductive pins are arranged on the packaging base, and are exposed in the recess and protrude out of the packaging base. A light emitting diode chip has two bump pads on one surface thereof. The light emitting diode chip is fixed in the packaging base by the surface with the bump welding pad facing to the recess. An anisotropic conductive adhesive is positioned between the light emitting diode chip and the recess to electrically connect the bump pad and the conductive pin.

Description

Chip flip-chip packaging structure and method of light-emitting diode

technical field

The invention relates to a package structure and a package method, in particular to a light emitting diode package structure and a package method.

Background technique

Chip flip-chip packaging technology is widely used in semiconductor component packaging technology. For light-emitting diodes, chip flip-chip packaging technology has the advantage of improving luminous efficiency. However, the known LED packaging structure suitable for flip-chip packaging uses gold balls to connect the electrodes of the LED and the conductive pins of the packaging structure, so the required equipment is different from the traditional LED packaging process equipment.

The equipment of the known flip-chip packaging process requires at least an ultrasonic device, so that the gold balls on the electrodes of the light-emitting diode and the gold balls on the conductive pins can generate enough heat to melt and connect the two rubbing gold balls when rubbing. Therefore, the introduction of this new technology is often accompanied by a high investment in equipment and an increase in the cost of new equipment adjustments.

Contents of the invention

The object of the present invention is to provide a chip flip-chip packaging structure and packaging method of light-emitting diodes to solve the above-mentioned problems of high investment and high cost of equipment in the known technology.

In order to achieve the above object, the present invention provides a chip flip-chip packaging structure of light emitting diodes. The package structure includes the following components: a package base has a recess. Two conductive leads insulated from each other are arranged on the package base, and both conductive leads are exposed in the recess and protrude outside the package base. An LED chip has two bump pads located on one surface thereof. The light-emitting diode chip is fixed in the package base with the surface having the bump pad facing the recess. An anisotropic conductive adhesive is located between the light-emitting diode chip and the recess, so as to electrically connect the bump pad and the conductive pin.

In order to achieve the above object, the present invention provides a chip flip-chip packaging method of light-emitting diodes: forming a photoresist layer on a light-emitting diode chip. The photoresist layer is patterned by means of exposure and development to expose the area of the light emitting diode chip where bump pads are to be formed. A plurality of bump pads are formed on the exposed area of the LED chip. A package base with a recess is provided. The light-emitting diode chip is pasted in the recess of the package base with the surface having bump pads by means of anisotropic conductive adhesive.

From the above, the chip flip-chip packaging structure and method of the light-emitting diode of the present invention can reduce many process costs and man-hours, and can overcome the problem that the material of the bracket is not suitable for the ultrasonic chip flip-chip bonding process.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

1 to 4 are flow charts of manufacturing bump pads suitable for light-emitting diodes in flip-chip packaging according to a preferred embodiment of the present invention; and

FIG. 5 to FIG. 6 are a flip-chip packaging method of a light emitting diode according to a preferred embodiment of the present invention.

Among them, reference signs:

104: Light-emitting diode chip 112a: Conductive pin

106: photoresist layer 112b: conductive pin

106a: Patterned depressions 114: Anisotropic conductive adhesive

107: Translucent area 114a: Conductive particles

108: Bump pad 114b: Glue

109: Surface 115: Depression

110: reflective layer 115a: concave bottom surface

111: Surface 116: Lighting direction

112: package base

Detailed ways

As mentioned above, the present invention provides a flip-chip packaging structure and method of light emitting diodes. The structure and method of flip chip packaging of light emitting diodes will be described in detail below in conjunction with preferred embodiments.

Please refer to FIG. 1 to FIG. 4 , which are cross-sectional views of a manufacturing process of bump pads of a light emitting diode. The bump pad manufacturing method of the light-emitting diode incorporates photolithography to quickly and accurately form the bump pad on the light-emitting diode chip. The photolithography process helps the distance between the bump pads to be narrower.

In FIG. 1 , firstly, a photoresist layer 106 is formed on the uncut LED chips 104 .

In FIG. 2, the photoresist layer 106 is then patterned by exposure and development to form a plurality of patterned recesses 106a. The patterned recesses 106a are used to expose the area of the LED chip 106 where bump pads are to be formed.

In FIG. 3 , metal pad material is filled into several patterned recesses 106 a by evaporation, electroplating or printing.

In FIG. 4 , the photoresist layer 106 is removed, and a bump pad 108 is formed on the LED chip 104 .

Please refer to FIG. 5 to FIG. 6 , which are flip-chip packaging methods of light emitting diodes. After the above-mentioned plurality of LED chips 104 are cut, they are respectively flip-chip packaged into the package base 112 . The package base 112 includes two conductive pins 112a, 112b and a recess 115 . Both conductive pins 112a and 112b are exposed in the recess 115 and protrude out of the package base 112 . The parts of the two conductive pins 112a, 112b protruding from the package base 112 are used for soldering to another circuit substrate (not shown in the figure) for electrical connection. Before the light-emitting diode chip 104 is pasted into the recess 115 of the package base 112, an anisotropic conductive paste 114 (Anisotropic Conductive Paste) is firstly filled. The anisotropic conductive adhesive 114 is a mixture of conductive particles 114a and glue 114b. When the LED chip 104 is pasted in the recess 115 , some of the conductive particles 114 a are used to electrically connect the bump pad 108 and the conductive pins 112 a and 112 b. However, since the conductive particles 114a are smaller than the gap between the LED chip 104 and the bottom surface of the recess 115a and are covered by the insulating glue 114b, the two bump pads 108 or the two conductive pins 112a, 112b are insulated. The anisotropic conductive adhesive 114 can be baked in an oven to accelerate solidification. After the LED chip 104 is attached to the recess 115 , a transparent encapsulant (not shown in the figure) can be filled in to fix the LED chip 104 in the recess 115 .

In addition, a reflective layer 110 (such as a metal layer) can be added in the light-transmitting region 107 (such as the P-type electrode region) in the LED chip 104 . The purpose of the reflective layer 110 is to block and reflect light towards the surface 109 , so that the LED chip 104 concentrates the light emitted from the surface 111 (for example, along the direction 116 ), so that the light emitting efficiency of the LED chip 104 is better.

It can be seen from the above-mentioned preferred embodiments of the present invention that the application of the chip flip-chip packaging structure and method of the light-emitting diode of the present invention can reduce a lot of costs and working hours. In addition, the chip flip-chip packaging structure and method can overcome the problem that the material of the bracket is not suitable for the ultrasonic chip flip-chip bonding process.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes All changes and modifications should belong to the scope of protection of the appended claims of the present invention.

Claims (12)

1, a kind of flip-chip soldering encapsulation structure of light-emitting diode is characterized in that, comprises at least:

One encapsulation base plate has a depression;

Two conductive pins insulated from each other are arranged on this encapsulation base plate, and this two conductive pin all is exposed in this depression and protrudes from outside this encapsulation base plate;

One light-emitting diode chip for backlight unit has two convex pads and is positioned at surface thereof, and this light-emitting diode chip for backlight unit is fixed in this encapsulation base plate towards this depression with this surface with convex pads; And

One anisotropic conductive is between this light-emitting diode chip for backlight unit and this depression, so as to electrically connecting this convex pads and this conductive pin.

2, the flip-chip soldering encapsulation structure of light-emitting diode according to claim 1, it is characterized in that, this anisotropic conductive comprises several conducting particless and viscose glue, in the time of in light-emitting diode chip for backlight unit is pasted on this depression, the part of these conducting particless is in order to electrically connect this convex pads and this conductive pin.

3, the flip-chip soldering encapsulation structure of light-emitting diode according to claim 1 is characterized in that, has a reflector layer in this light-emitting diode chip for backlight unit near this surface with convex pads.

4, the flip-chip soldering encapsulation structure of light-emitting diode according to claim 3 is characterized in that, this reflector layer is positioned at a transparent area of this light-emitting diode chip for backlight unit.

5, the flip-chip soldering encapsulation structure of light-emitting diode according to claim 4 is characterized in that, this transparent area is a P type electrode district.

6, a kind of flip-chip sealing method of light-emitting diode is characterized in that, comprises at least:

Form a photoresist layer on a light-emitting diode chip for backlight unit;

Borrow exposure and this photoresist layer of visualization way patterning to expose the zone that will form convex pads of this light-emitting diode chip for backlight unit;

Form the exposed region of several convex pads in this light-emitting diode chip for backlight unit;

Encapsulation base plate with a depression is provided; And

Borrow anisotropic conductive that this light-emitting diode chip for backlight unit is pasted in this depression of this encapsulation base plate with this surface with convex pads.

7, the flip-chip sealing method of light-emitting diode according to claim 6 is characterized in that, this anisotropic conductive comprises several conducting particless and viscose glue.

8, the flip-chip sealing method of light-emitting diode according to claim 6 is characterized in that, this encapsulation base plate comprises two conductive pins, and this two conductive pin all is exposed to this depression and protrudes from outside this encapsulation base plate.

9, the flip-chip sealing method of light-emitting diode according to claim 6 is characterized in that, has a reflector layer in this light-emitting diode chip for backlight unit near this surface with convex pads.

10, the flip-chip sealing method of light-emitting diode according to claim 9 is characterized in that, this reflector layer is positioned at a transparent area of this light-emitting diode chip for backlight unit.

11, the flip-chip sealing method of light-emitting diode according to claim 10 is characterized in that, this transparent area is a P type electrode district.

12, the flip-chip sealing method of light-emitting diode according to claim 6 is characterized in that, these convex pads are formed at the exposed region of this light-emitting diode chip for backlight unit with evaporation, plating or mode of printing.

Images