Brief introduction to LED chip manufacturing process

Jul 26th, 2012 | Posted by | Filed under LED Light
manufacturing process includes the 13-step process, as follows:


1. inspection


Microscopy: surface whether there is mechanical damage and pitting hemp pit (lockhill chip and electrode size meets the technical requirements of electrode pattern is complete


2.LED expansion


Because LED chip after dicing continued to arrange closer spacing is small (about 0.1mm), is not conducive to operation after operation. We enlarged chip bonding chip membrane expansion stretch spacing is the LED chip to about 0.6mm. You can also use the manual expansion, but it is likely to cause chips drop wasted and other bad issues.


3.LED dispensing
LED stand on the appropriate location of silver colloid, or rubber. (GaAs, SiC conductive substrate, electrode red, yellow, yellow-green chip on the back, with silver rubber. Insulating substrates of sapphire blue, green LED chips, with insulated rubber to secure the chip.


Processing difficulty lies in the dispensing volume control, in Colloid height, dispensing locations are detailed technical requirements.
Silver plastic and rubber in storage and use has stringent requirements, silver colloid woke up, mixing of materials, use of time is a matter of process must pay attention to.


4.LED adhesive
And contrary to the dispensing, adhesive glue is prepared first LED silver adhesive electrodes on the back, and then installed on the LED back LED with a silver plastic holder. Efficiency is much higher than the preparation of adhesive dispensing, but not all products can be used by technology.


5.LED manual Gill


After the expansion of LED chips (preparation of glue or not to glue) rehousing in thorn on the fixture, LED stent placed underneath the fixture, LED chips with a PIN under the microscope on one thorn to the appropriate location. Thorn and automatically compared to the rack by hand would have the advantage, easy to switch to a different chip at any time, apply to the need to install a variety of chip products.


6.LED automatic rack


Automatic rack is a combination of PCBA (dispensing) chips and installed two steps, first in points LED bracket silver colloid (rubber), and then use the vacuum nozzle LED chip mobile location, and then placed in the appropriate bracket locations. Automatic programming process mainly to familiarize themselves with the equipment operation, PCBA and the precision of the device at the same time to make any adjustments. Used as far as possible in the selection of nozzle bakelite nozzle to prevent damage to the surface of LED chip, especially the blue and green chips must be bakelite. Scratch the surface of the chip because steel mouth current diffusion layer.
Sintered 7.LED
Sintered to make silver adhesive curing, sintering require temperatures to be monitored to prevent poor batch. Silver colloid general control of sintering temperature 150 ℃, sintering time of 2 hours. According to the actual situation can be resized to 170 ° c, 1 hour. Insulated 150 ℃, 1 hour.


Silver adhesive must be requested by the technology of sintering oven 2-hour (or 1 hour) opens replacing sintered products, not free to open in the middle. Sintering oven not other uses, to prevent pollution.


8.LED pressure welding
Pressure on the purpose of welding electrodes into the LED chip, complete product lead connections both inside and outside work.
LED pressure welding of aluminum wire with gold wire welding and pressure welding in two ways. Image on the right is a pressure welding of aluminum wire, pressure on the LED chip electrodes before the 1th, then aluminum wire to the corresponding upper-bracket, aluminum wire snapped after pressure on the 2nd. Gold wire welding process in 1th before firing a ball, and the rest is similar to the process.
Pressure welding is a key link in LED packaging technology, the craft is mainly need to monitor pressure welding on gyros ‘ (aluminum wire) arch wire shapes, shape of solder, pull.


9.LED sealant
LED packaging adhesives, potting, molding three main. Difficulty of process control is basically a bubble, material shortage and black. Designed primarily for materials selection, with good choice of epoxy and bracket. (General LED not by gas-tightness test)


9.1LED dispensing:


TOP-LED and Side-LED application of dispensing package. Manual dispensing package requires high levels of action (in particular, white light LED), the main difficulty is the dispensing volume control, because the epoxy thickens during use. Dispensing of the white-light LED led light color phosphor precipitation is also an issue.


9.2LED glue package
Take the form of encapsulation in the Lamp-LED package. Potting process is LED inside the mold cavity injection of liquid epoxy, and then insert the pressure welding good LED stent placed in the oven after epoxy curing, LED from the protrusion that is formed in the cavity.


9.3LED molding package


The pressure welding good LED stent put in the mold, up and down two pairs of hydraulic machine for mold clamping and vacuum, solid epoxy injection rubber road entrance into the heating is provided by hydraulic pressure molding plastic road, epoxy down plastic road access LED the slot and curing.


10.LED after curing and curing
Curing refers to encapsulating epoxy curing, epoxy curing conditions of 135 ℃, 1 hour. Molded packaging generally 150 ¡æ, 4 minutes. Curing lets the epoxy fully cure after, LED heat aging at the same time. After curing for improving epoxy and bracket (PCB) bonding strength is very important. General conditions for 120 ° c, 4 hours.


11.LED cut gluten and scribing
Because the LED are connected together in the production (as opposed to an individual), LED Lamp package using cutting reinforced cut off even LED stent reinforcement. SMD-LED is a PCB Board, need to work dicing machine to complete the separation.


12.LED test
Test LED test of photoelectric parameters, dimensions, while LED sorting products according to customer requirements.