CN104910855A

CN104910855A - Conductive adhesive used for flip chip LED packaging

Info

Publication number: CN104910855A
Application number: CN201510270953.4A
Authority: CN
Inventors: 叶志伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-05-25
Filing date: 2015-05-25
Publication date: 2015-09-16

Abstract

The invention discloses a conductive adhesive used for flip chip LED packaging. The conductive adhesive comprises an insulation adhesive body and conductive capsules dispersed in the insulation adhesive body; the conductive capsules comprise insulation capsule skin and conductive powder packaged with the insulation capsule skin; and fracture of the capsule skin is caused when the capsule skin is pressed to a certain degree. When the conductive adhesive is used, the space of a chip electrode and a base plate is full of conductive substances, so that electrical connection is realized, and the electrical connection is more reliable than electrical connection realized via single conductive particle, insulating properties among the conductive capsules are not influenced by conductive capsule content, and the content is easy to control.

Description

A kind of conductive resin for flip LED encapsulation

Technical field

The present invention relates to the conductive resin be electrically connected between a kind of electronic component, particularly a kind of conductive resin for flip LED encapsulation.

Background technology

Photodiode (Light Emitting Diode), abbreviation LED is a kind of can be the solid-state semiconductor device of visible ray by electric energy conversion.As new and effective solid light source, semiconductor lighting has the remarkable advantages such as life-span length, energy-saving and environmental protection, safety, widespread use and illumination, display, signal lamp field.The main formal dress of existing LED encapsulation structure, upside-down mounting with vertical three kinds, wherein flip-chip packaged day by day becomes the main flow of lighting field LED with its excellent electroconductibility and thermal diffusivity.Traditional flip-chip packaged need by the salient point of chip surface by welding system welding and substrate, the control of salient point and substrate distance and levelness directly has influence on the welding quality of chip, apart from excessive, weld and easily cause rosin joint, apart from too small, weld and easily cause short circuit, levelness difference easily causes missing solder.Again because traditional flip LED welding system equipment cannot the quality of detection chip welding quality, cause flip-chip packaged LED yield low.

For overcoming the problem of Conventional flip LED, prior art different direction conductive resin replaces the weldprocedure in Conventional flip LED process.Described different direction conductive resin is mixed by insulative glue and metallics, by controlling the content of metallics, is distributed in insulative glue with making metallics uniform intervals.First on base plate for packaging, apply described different direction conductive resin during encapsulation, then chip is compressed on the substrate, after the glue solidifies, chip is fixed on substantially.At this moment, the chien shih that vertical direction upper part metallics is crimped to chip electrode and substrate is electrically connected, and in horizontal direction, other metallicss are isolated and opposing insulation owing to there being insulative glue.Adopt this different direction conductive resin Problems existing: 1, control conducting particles ratio difficulty large, when conducting particles ratio is too much, the short circuit of electrode horizontal direction may be caused; When conducting particles ratio is very few, may cause clamping less than metallics between chip electrode and substrate.2, be electrically connected unreliable, because the conducting particles clamped random in the process that it relies on chip to compress conducts electricity, expand with heat and contract with cold in LED use procedure, when the distance between chip electrode and substrate changes, easily cause resistance sharply to increase or open circuit.

Summary of the invention

In order to overcome the deficiencies in the prior art, the invention provides a kind of conductive resin for flip LED encapsulation.

The present invention solves the technique means that its technical problem adopts: a kind of conductive resin for flip LED encapsulation, the conduction capsule comprising insulation colloid and be dispersed in described insulation colloid, the conductive powder body that described conduction capsule comprises insulation capsule skin and is wrapped in described insulation capsule skin, breaks when described capsule skin is pressed to certain proportion.

The invention has the beneficial effects as follows: owing to comprising the conduction capsule being wrapped up in conductive powder body by insulation capsule suitcase in conductive resin of the present invention, when conduction capsule core plate electrode and substrate press to a certain degree, insulation capsule skin breaks, be full of conductive powder body between chip electrode with substrate and formed and be electrically connected, more reliable than the electrical connection of single conductive particle; Continue to keep insulating due to the existence of the capsule skin that insulate between conduction capsule outside chip electrode and substrate, by the impact that conduction capsule content is how many, conduction capsule content controls easily.

As a further improvement on the present invention, described conductive powder body is silver powder, and it has good electroconductibility and the diffustivity in insulation colloid.

Improve further as the present invention, described insulation capsule skin is organosilicon impregnated membranes.

Improve further as the present invention, described insulation capsule skin is polyacetals modified organic silicon impregnated membranes, and its anti-pressure ability is poor, easily breaks at pressurized, is conducive to conductive powder body diffusion.

Improve further as the present invention, the diameter of described insulation capsule skin is 4-10 micron, breaks when being pressed to the 30%-60% of original diameter.

Improve further as the present invention, the diameter of described insulation capsule skin is 5 microns, breaks when being pressed to 2 ~ 3 microns.

Improve further as the present invention, the material of described insulation colloid is silica gel or epoxy resin.

Improve further as the present invention, the material of described insulation colloid also comprises aluminium hydroxide.

Accompanying drawing explanation

Fig. 1 is the constituent structure schematic diagram of conductive resin of the present invention;

Fig. 2 is that the structural representation of capsule is conducted electricity in the present invention;

Fig. 3 is the view of the present invention in flip LED encapsulation

Fig. 4 is the partial enlarged drawing of Fig. 3.

Embodiment

Below in conjunction with drawings and Examples, the present invention is further detailed explanation.

With reference to figure 1, a kind of conductive resin for flip LED encapsulation of the present invention, the conduction capsule 2 comprising insulation colloid 1 and be dispersed in described insulation colloid, the conductive powder body 22 that described conduction capsule 2 comprises insulation capsule skin 21 and is wrapped in described insulation capsule skin, breaks when described capsule skin 21 is pressed to certain proportion.

Described insulation colloid 1 is the good thermosetting resin of the thermal conductivity such as silica gel or epoxy resin, is the setting rate promoting thermosetting resin, also can mix the alumag of trace in conductive resin.The effect of insulation colloid 1 is chip 3 to be fixed on substrate 4, is also heat-conduction medium heat being passed to substrate from chip simultaneously.

As shown in Figure 2, it is outer is insulation capsule skin 21 to described conduction capsule 2, is coated with conductive powder body 22, as silver powder, bronze or copper powder in insulation capsule skin 21.Described insulation capsule skin 21 is that ductility is poor, the crackly material of pressurized, and as machine silicon impregnated membranes or polyacetals modified organic silicon impregnated membranes, it is depressed into certain proportion and breaks as during 30%-60%.Described conducting material 22 can rapid diffusion after mixing with described insulation colloid 1.As preferrred embodiment of the present invention, the diameter of described insulation capsule skin 21 is 4-10 micron, breaks when being pressed to the 30%-60% of original diameter, and can ensure that chip electrode and substrate distance are comparatively near like this, chip electrical connects reliably, and heat conduction is good.For achieving the above object, optimum embodiment is the diameter of described insulation capsule skin 21 is 5 microns, breaks when being pressed to 2 ~ 3 microns.

With reference to figure 3 and Fig. 4, the present invention is used to carry out the processing step encapsulated:

1) conduction capsule 2 is evenly spread in the good insulation colloid 1 of thermal conductivity;

2) described insulation colloid 1 is dropped on base plate for packaging 4, then the electrode position on the electrode of described upside-down mounting LED chip 3 alignment substrate 4 is placed;

3) use pressing machine to press described upside-down mounting LED chip 3, apply voltage simultaneously at described base plate for packaging 4 positive and negative electrode, when the conducting of described upside-down mounting LED chip 3, and when reaching specified current flow, described pressing machine stops pressing;

4) be heating and curing described insulation colloid 1.

In the 3rd of above-mentioned technical process) in, because the partially conductive capsule 2 in insulation colloid 1 is crimped between electrode 31 and substrate 4, when chip 3 continuing exert pressure to time to a certain degree, the insulation capsule skin 21 of described electric capsule 2 breaks, conductive powder body 22 in insulation capsule skin 21 is released, be diffused between electrode 31 and substrate 4, electrode 31 is electrically connected with substrate 4.In the starting stage of current lead-through, because conducting material 22 is not very tight, resistance is larger; After continuing to exert pressure, conducting material 22 becomes tight, and resistance reduces, and electric current increases gradually.The conduction capsule 2 of leading material 22 is wrapped up by insulation capsule skin 21 owing to comprising in insulation colloid 1 of the present invention, when conduction capsule 2 is clamped to a certain extent by chip electrode 3 and substrate 4, insulation capsule skin 21 breaks, be full of between chip electrode 3 with substrate 4 to lead material 22 and formed and be electrically connected, more reliable than the electrical connection of single conductive particle; Continue to keep insulating due to the existence of the capsule skin 21 that insulate between conduction capsule 2 outside chip electrode 3 and substrate 4, by the impact that conduction capsule 2 content is how many, conduction capsule 2 content controls easily.

Claims

1. the conductive resin for flip LED encapsulation, it is characterized in that: the conduction capsule comprising insulation colloid and be dispersed in described insulation colloid, the conductive powder body that described conduction capsule comprises insulation capsule skin and is wrapped in described insulation capsule skin, breaks when described capsule skin is pressed to certain proportion.

2. a kind of conductive resin for flip LED encapsulation according to claim 1, is characterized in that: described conductive powder body is silver powder.

3. a kind of conductive resin for flip LED encapsulation according to claim 1, is characterized in that: described insulation capsule skin is organosilicon impregnated membranes.

4. a kind of conductive resin for flip LED encapsulation according to claim 3, is characterized in that: described insulation capsule skin is polyacetals modified organic silicon impregnated membranes.

5. a kind of conductive resin for flip LED encapsulation according to claim 1, is characterized in that: the diameter of described insulation capsule skin is 4-10 micron, breaks when being pressed to the 30%-60% of original diameter.

6. a kind of conductive resin for flip LED encapsulation according to claim 5, is characterized in that: the diameter of described insulation capsule skin is 5 microns, breaks when being pressed to 2 ~ 3 microns.

7. a kind of conductive resin for flip LED encapsulation according to claim 1, is characterized in that: the material of described insulation colloid is silica gel or epoxy resin.

8. a kind of conductive resin for flip LED encapsulation according to claim 7, is characterized in that: the material of described insulation colloid also comprises aluminium hydroxide.