Industry news

2016May

LED packaging process flow

From: www.szbako.com Data:02/05/2016

a conductive adhesive, conductive silver glue
conductive adhesive is an integral part of IED package for production of a glue, the requirement of conductive silver paste is conductive, heat conduction performance is better, the shear strength to and cohesive force is stronger. UNINWELL international conductive adhesive and conductive silver conductive adhesive good conductivity, strong shear stress, rheological properties are also very good, and the moisture absorption is low. Particularly suitable for high power and high brightness LED package. In particular, the UNINWELL 6886 series conductive silver glue, its thermal conductivity is: 25.8 shear strength: 14.7, called the industry’s most.

two encapsulation process LED
1. of the task of the
is connected to the LED chip to connect the electrode, while protecting the LED chip, and play a role in improving the efficiency of light extraction. The key process for assembling, welding, packaging. LED
2. package form
LED package can be said to be varied, mainly according to different applications using the appropriate size of the shape, cooling countermeasures and the effect of light. LED according to the package form has Lamp-LED, TOP-LED, Side-LED, SMD-LED, High-Power-LED, etc..
3. LED packaging process package
4. process 1. The test chip
microscopy: surface materials whether mechanical damage and hemp dot hemp pit lockhill
chip size and electrode size meets the process requirements
electrode pattern is complete
2. expanding sheets
due to the LED chip dicing still ranks close spacing is very small (about 0.1 mm), is not conducive to the process operation. We use the expansion machine to expand the film bonding chip, LED chip spacing is stretched to about 0.6mm. Can also be used by hand, but it is easy to cause the chip to drop a waste and other undesirable issues.
3.
in dispensing LED stent corresponding points on the silver colloid or insulating rubber. (with the back electrode for GaAs, SiC conductive substrate, red light, yellow light, yellow green chip, using silver colloid. The blue and green LED chips are used to fix the chip on the sapphire insulating substrate.
) is to control the dispensing process difficulties, in the process of colloidal height, dispensing position are detailed. Due to the strict requirement of the storage and use of the silver colloid and the insulating adhesive, the
, the stirring and the use time of the silver colloid are all the matters that must be paid attention to in the process.
4. preparing
and glue dispensing the contrary, gum is compound prepared firstly rouged to silver glue coated on the LED on the back electrode, and then put back with a silver colloid LED mounted on the LED bracket. The preparation efficiency is much higher than the glue dispensing, but not all products are suitable for preparation of rubber technology. 5 hand thorn
LED chip will be expanded after the expansion of the LED chip (preparation of plastic or rubber) placed in the spine of the fixture, the LED stent under the clamp, under the microscope with a needle to the corresponding position of a needle. Hand thorn and automatic racking than a benefit, is convenient for replacement at any time on different chips, applicable to need to install multiple chip product.
6. automatic rack mounting
automatic rack is actually combines gluing (dispensing) and installing chips into two steps, first in the LED bracket on silver colloid (insulating glue), then by vacuum suction nozzle LED chip ceiling mobile location, and then to the resettlement of in the corresponding position of the stent. Automatic rack in the process to be familiar with the main equipment operation and programming, to adjust the glue equipment and installation accuracy. In the selection of suction nozzle try to use bakelite nozzle, prevent the damage to the surface of the LED chip, especially blue, green chips must be made of bakelite. Because the steel mouth will scratch the surface of the chip current diffusion layer. The purpose of
7. sintering
sintering is to make the silver glue solidified, the sintering temperature is required to monitor the temperature, so as to prevent the.
silver plastic sintering temperature is generally controlled at 150 degrees Celsius, sintering time of 2 hours. According to the actual situation can be adjusted to 170 degrees, 1 hours.
insulation is generally 150 degrees Celsius, 1 hours.
silver plastic sintering oven must be according to the technological requirements of 2 hours (or 1 hours) to open the replacement of sintered products, the middle shall not be free to open. Sintering oven shall not be used for other purposes, to prevent pollution.
8. pressure welding
welding of the purpose of the electrode lead to the LED chip, the completion of the product inside and outside the wire connection. The pressure welding technology of
LED has two kinds of gold wire ball welding and aluminum wire pressure welding. Pictured to the right is the process of aluminum wire bonding, first in the LED chip electrode pressure on the first point, aluminum wire to the corresponding to the top of the bracket, pressure on the second point after tensile aluminum wire. Gold wire ball welding process is before the first point to burn a ball, and the rest of the process is similar to the.
pressure welding is the key link in the LED packaging technology, the main need to monitor the process is the pressure welding wire (Lv Si) arch wire shape, the shape of the solder joint, pull.
to pressure the in-depth research on welding process involves many aspects, such as gold (AL) silk materials, ultrasonic power, pressure welding pressure, selection of capillary (steel mouth), chopper (steel mouth) trajectories, and so on. (below is under the same conditions, two different capillary extrusion of solder joints in micro photos, both in the micro structure differences, thus affecting the quality of the products. We are no longer tired here. A dispensing, potting, molded three main
9. dispensing package
LED package. The difficult point of the basic process control is the bubbles, the lack of material, the black spot. Design is mainly on the selection of materials, use a combination of good epoxy and stents. (general LED not through the air tightness test of TOP-LED and Side-LED) for dispensing package
as shown on the right. Manual dispensing package level of operation requirement is very high (especially white LED), the main difficulty is control of the dispensing amount, because the epoxy in the use process will thicken. White LED also causes the dispensing color light precipitate fluorescent powder. Welcome to visit the LED network (
10.) world glue package
Lamp-LED package using the form of potting. Potting process is first in led the molding cavity injection of liquid epoxy, then insert the pressure welding LED stent, into the oven and let the epoxy curing, led from the mold cavity prolapse is formed.
11. molded package
will pressure welding LED stent is placed in a mould, will be on the two side mold with hydraulic press mould and vacuum, solid epoxy into note glue channel inlet heating hydraulic top rod is pressed into a mold plastic, epoxy glue into the various LED molding groove along the and solid.
12. curing and post curing
curing is to refer to the curing of the epoxy resin, and the curing conditions are 135 degrees C, 1 hours. Molded packages generally at 150 degrees, 4 minutes. After curing the
,
13. is cured in order to fully cure the epoxy, while the thermal aging of LED. Post curing is very important for improving the bonding strength of epoxy and support (PCB). General conditions are 120 degrees, 4 hours.
14. cut tendons and dicing
due to led in production is even together (not individual), the lamp package led by cutting off the bars LED bracket connecting rib. SMD-LED is on a PCB board, need dicing machine to complete the separation work.
15. test
test LED photoelectric parameter, test dimensions, also according to customer requirements of LED products were bewildered
16. packaging
counting and packing of the finished product. Ultra bright LED needs anti-static packaging.

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