CN101692476A

CN101692476A - Die bonding method for improving LED luminous efficiency

Info

Publication number: CN101692476A
Application number: CN200910201685A
Authority: CN
Inventors: 黄金鹿; 黄莺; 缪应明; 吴海生
Original assignee: Suzhou Zhongze Optoelectronics Technology Co Ltd
Current assignee: Suzhou Zhongze Optoelectronics Technology Co Ltd
Priority date: 2009-10-15
Filing date: 2009-10-15
Publication date: 2010-04-07

Abstract

The invention relates to a die bonding method for improving LED luminous efficiency, which comprises the following steps that: firstly, a layer of bonding material within an appropriate range is coated on a die bonding surface of the bottom of an LED crystal grain fixing pit of which a metal substrate is provided with a reflective layer; after the bonding material is coated on the die bonding surface, LED crystal grains of which the bottom surfaces are provided with metal layers are arranged at die bonding positions where the bonding material is attached to the substrate; and after being compacted, the crystal grains are heated to an eutectic temperature so as to enable metals on the bottom surfaces of the LED crystal grains to implement eutectic welding with the substrate through solder paste. The bonding material in the method is only coated on a contact surface between the LED crystal grains and the metal substrate without influencing LED three-dimensional luminescence, and light emitted from the periphery of the bonding material is reflected by the fixing pit to improve the luminous efficiency.

Description

A kind of die-bonding method that improves the LED light extraction efficiency

Technical field

The present invention relates to LED die package field, the die-bonding method of the definite a kind of LED of raising light extraction efficiency of saying so.

Background technology

In the LED encapsulation field, Gu crystalline substance is an important step, the quality of its quality directly influences light extraction efficiency and the useful life of LED, different selected solid crystal type according to the size of LED power and packaging technology is different, in general, low-power LED crystal grain conducts heat by insulating cement fixed electrode pin and gets final product; The LED that power is big slightly can be by heat conduction elargol or silica gel adhesion heat radiation; Usually adopt the fixing heat radiation of mode of high heat conduction elargol or eutectic welding for watt level LED, the eutectic welding is because heat conductivility excellence advantage in the above high-power LED encapsulation of watt level is outstanding, and general eutectic alloy that adopts and metal price are all than higher, Gu and adopt the technology of eutectic tin cream, problem owing to technology and operation when solid crystalline substance often is wrapped in the part of LED crystal grain in the crystal-bonding adhesive, so the parcel scope will influence the LED bright dipping, and the light that will have partial L ED to send owing to the restriction that has encapsulating structure now can not penetrate and have influence on LED and get optical efficiency simultaneously.

Summary of the invention

For solving the problem of above-mentioned LED bright dipping deficiency, the invention provides a kind of die-bonding method that helps to improve the LED light extraction efficiency.

Technical scheme of the present invention is as follows: a kind of die-bonding method that improves the LED light extraction efficiency comprises the steps:

The metal base preparation: metal base is made by the high-thermal conductive metal material, generally adopts the copper coin electroplate, is furnished with fixedly pit of LED crystal grain on the metal base, pit inner surface plating reflector layer, and the bottom surface is solid crystal face.

Then material preparation: then material is preferentially selected the eutectic tin cream.

Get glue and some glue: utilize Glue dripping head to dip in to get eutectic tin cream point to invest on the metal base fixedly pit baseplane of LED crystal grain, it is moderate that smearing thickness is made every effort to, then material only is applied in metal base LED the crystal grain fixedly baseplane of pit and the contact site of LED crystal grain bottom surface metal, guarantees certain adhere to pulling force and unlikely other bread of crystal grain is rolled in the colloid.

The eutectic welding step: the LED crystal grain that the bottom surface is had metal level places the pedestal point that the solid brilliant position of tin cream is arranged, and compacting makes the metal of led chip bottom surface and pedestal realize the eutectic welding by tin cream after hot plate, baking box or continuous tunnel furnace etc. are warmed up to eutectic temperature.

Good effect of the present invention: the solid crystal type of the present invention reduces the then area coverage of material, reduce the outgoing that hinders LED light because of the covering of following material to greatest extent, be furnished with fixedly pit of LED crystal grain on the metal base, be coated with reflector layer around the pit, the light that LED like this sends improves exitance through the reflection of reflector layer all around, strengthens directive property.

Description of drawings:

Fig. 1: be die-bonding method FB(flow block) of the present invention;

Fig. 2: be metal base schematic diagram of the present invention;

Fig. 3: for the present invention puts the glue schematic diagram;

Fig. 4: be eutectic welding back structural representation.

Indication legend in the accompanying drawing

1, metal base 2, reflector layer 3, solid crystal face 4, then material 5, LED crystal grain

Embodiment

A kind of die-bonding method that improves the LED light extraction efficiency comprises as shown in Figure 1: the preparation of metal base, the then preparation, the preparation of getting glue and some glue, LED crystal grain of material, at last for eutectic welds, below the above several steps of division.

Be illustrated in figure 2 as metal base (1), metal base is made by the high-thermal conductive metal material, the general copper coin electroplate that adopts, be furnished with fixedly pit of LED crystal grain on the metal base, pit adopts bell mouth shape usually, horn mouth inner surface polishing back plating reflector layer (2), the pit bottom surface is solid crystal face (3).

Then material is preferentially selected the eutectic tin cream.

The preparation of LED crystal grain, the solid crystal type of the present invention is applicable to the encapsulation of W class large power LED crystal grain, and the following LED of 0.5W does not need the eutectic welding.

Be illustrated in figure 3 as a glue process, utilizing Glue dripping head to dip in to get then material (4) is that eutectic tin cream point invests on the metal base fixedly pit baseplane of LED crystal grain, it is moderate that smearing thickness is made every effort to, then material only is applied in metal base LED the crystal grain fixedly baseplane of pit and the contact site of LED crystal grain bottom surface metal, guarantees certain adhere to pulling force and unlikely other bread of crystal grain is rolled in the colloid.

As shown in Figure 4: the LED crystal grain that the bottom surface is had metal level places the pedestal point that the solid brilliant position of tin cream is arranged, and compacting makes the metal of led chip bottom surface and pedestal realize the eutectic welding by tin cream after hot plate, baking box or continuous tunnel furnace etc. are warmed up to eutectic temperature.

Claims

1. a die-bonding method that improves the LED light extraction efficiency is characterized in that: fixedly consolidate the then material that at first is coated with one deck proper range on the crystal face in the bottom of pit at the LED crystal grain that has reflector layer on the metal base; The LED crystal grain that again bottom surface is had metal level after finishing places the pedestal point that the then Gu Jingmianchu of material is arranged, and is warmed up to eutectic temperature after the compacting, makes the metal of LED crystal grain bottom surface and pedestal realize the eutectic welding by tin cream.

2. a kind of die-bonding method that improves the LED light extraction efficiency according to claim 1, it is characterized in that: described metal base is made by the high-thermal conductive metal material, be furnished with fixedly pit of LED crystal grain on the metal base, the pit inner surface is coated with reflector layer, and the bottom surface is solid crystal face.

3. a kind of die-bonding method that improves the LED light extraction efficiency according to claim 1 is characterized in that: described then material is preferentially selected the eutectic tin cream.

4. a kind of die-bonding method that improves the LED light extraction efficiency according to claim 1, it is characterized in that: described then material only is applied in metal base LED the crystal grain fixedly baseplane of pit and the contact site of LED crystal grain bottom surface metal, follows material other five face of LED crystal grain is not produced parcel.