LED chip on board (COB) packaging process

- Jan 17, 2019-

LED chip on board (COB) packaging process


The galloping machine provides a uniform spread of the zero-chirping LED wafer film provided by the manufacturer, so that the LED die which is tightly displayed on the surface of the film is opened to facilitate the puncturing.


The first step: crystal expansion


The galloping machine provides a uniform spread of the zero-chirping LED wafer film provided by the manufacturer, so that the LED die which is tightly displayed on the surface of the film is opened to facilitate the puncturing.


The second step: adhesive


Place the crystal-expanded crystal expansion ring on the surface of the adhesive machine that is not scraping the silver paste layer, and carry the silver paste on the back. Point silver paste. Suitable for disassembling LED chips. Use a dispenser to spot the right amount of silver paste on the PCB printed circuit board.


The third step: put the thorn frame


The crystallized crystal expansion ring is placed outside the lancet frame, and the operator is puncturing the LED chip on the PCB printed circuit board with a lancet under the microscope.


Step 4: Put in the hot cycle oven


Put the punctured PCB printed circuit board into the heat cycle oven for a period of time, and then remove it after the silver paste is solidified (not long-time release, otherwise the LED chip coating will be baked yellow, that is, oxidized, which makes the bonding difficult). If there is no LED chip bonding, the above steps are required; if the IC chip is bonded, the above steps are cancelled.


The fifth step: sticky chip


Put a proper amount of red glue (or vinyl) on the PCB position of the PCB printed circuit board with the dispenser, and then put the IC die on the red or black glue with anti-static equipment (solid air suction pen or female). .


Step 6: Drying


Put the bonded die into the heat cycle oven and put it on the large flat heating plate for a period of time. It can also be naturally cured (longer time).


Step 7: Bonding (line)


The aluminum wire bonding machine is used to bridge the wafer (LED die or IC chip) to the pad aluminum wire on the PCB, that is, the inner lead wire of the COB.


Step 8: Pretest


Use the common inspection tool (the COB with different uses for different purposes, the simple one is the high-precision steady-state current) to detect the COB board, and repair the unqualified board.


Step 9: Dispensing


The dispenser is equipped with a suitable amount of AB glue to the bonded LED die. The IC is sealed with black rubber and then sealed according to customer requirements.


Step 10: Curing


Put the sealed PCB printed circuit board into the heat cycle oven and put it under constant temperature. Set different drying time according to requirements.


The eleventh step: post test


The sealed PCB printed circuit board is then tested for electrical performance using a common inspection tool to distinguish between good and bad. With the advancement of technology, it is packaged in an aluminum substrate COB package, a COB ceramic COB package, and an aluminum substrate MCOB package.