What is COB Packaging
COB Packaging is Packaging Process of Chip On Board. The first is the surface of the substrate with a conductive epoxy resin (epoxy resin mixed with silver particles with covered silicon) placed, and then placed in a silicon wafer direct heat treatment to the silicon substrate surface, firmly fixed on the substrate, then using wire bonding on the silicon wafer and the substrate directly establish electrical connections.
Packaging Process of COB
1 Expanding crystal
Expansion machine manufacturers will provide the entire LED chip the film uniformity expansion, attached to the surface of the film closely spaced LED die is opened, easy thorn crystal.
Gum will be extended to the good crystal ring expansion on scraping the surface of the good silver paste layer gum machine, the back of the silver paste. Silver points. Apply in bulk LED chip. Using the right amount of silver paste dispenser point on the PCB printed circuit board.
3 Ready Silver crystal ring expansion into the thorn crystal frame, LED chip under a microscope by the operator with a thorn crystal pen thorn in the PCB printed circuit board.
4 The thorn good crystal PCB (printed circuit board) the thermostat standing for some time into the thermal cycle oven until the paste is removed after curing (not long home, or roasted yellow LED chip coating, oxidation, to the bonding cause difficulties). If the LED chip bonding, you need more than a few steps; IC chip bonding cancel the above steps.
5 Sticky Chip
The right amount of red plastic dispenser on the IC position of the PCB (printed circuit board) (or vinyl), and then anti-static equipment (vacuum suction pen or sub) IC die properly on red plastic or vinyl.
Will stick die on the large flat heating plate the thermostat standing for some time, naturally cured (longer) into the thermal cycle oven.
7 Wire Bonding
The use of aluminum wire bonders pad aluminum wire bridge chip (LED die or IC chip) and the PCB, the corresponding inner lead bonding, COB.
The use of special detection tools (different devices for different purposes according to the COB, is the high-precision power supply) detection COB board, the board failed to re-repair.
Using the dispenser will deploy the AB glue right amount locations you to good LED die bonding, IC package with vinyl, and then the appearance of the packaging according to customer requirements.
PCB (printed circuit board) will seal the plastic into the thermal cycle oven thermostat can be set to different drying time standing, upon request.
Encapsulated PCB (printed circuit board) and then dedicated detection tools electrical performance test to distinguish between good or bad.
Compared with other packaging technology, COB technology is much economic (only about 1/3 of the same chip), space saving, mature technology, so it is widely used in the field of semiconductor packaging.
Addition: Nowadays, COB Light Source is widely used in LED Spotlight, LED Downlight and LED Floodlight etc.