COB LED Packaging Process

Step 1: Crystal expansion. Use an expansion machine to evenly expand the entire LED chip film provided by the manufacturer, so that the LED crystals closely arranged on the surface of the film are pulled apart for easy crystal piercing.
Step 2: Back glue. Place the crystal expansion ring with the expanded crystal on the back glue machine surface with the silver paste layer scraped, and apply silver paste on the back. Apply silver paste. Applicable to bulk LED chips. Use a glue dispenser to apply an appropriate amount of silver paste on the PCB printed circuit board.
Step 3: Place the crystal expansion ring with the silver paste prepared in the crystal piercing rack, and the operator will pierce the LED chip on the PCB printed circuit board with a crystal piercing pen under a microscope.
Step 4: Put the PCB printed circuit board with the pierced crystal into a heat cycle oven at a constant temperature for a period of time, and take it out after the silver paste is cured (do not leave it for a long time, otherwise the LED chip coating will be baked yellow, that is, oxidized, causing difficulties in bonding). If there is LED chip bonding, the above steps are required; if only IC chip bonding is required, the above steps are cancelled.
Step 5: Glue the chip. Use a glue dispenser to apply an appropriate amount of red glue (or black glue) on the IC position of the PCB printed circuit board, and then use an anti-static device (vacuum suction pen or sub) to correctly place the IC bare chip on the red glue or black glue.
Step 6: Drying. Put the bonded bare chip into a thermal cycle oven and place it on a large flat heating plate at a constant temperature for a period of time, or it can be cured naturally (for a longer time).
Step 7: Bonding. Use an aluminum wire bonding machine to bridge the chip (LED crystal or IC chip) with the corresponding pad aluminum wire on the PCB board, that is, the inner lead welding of the COB.
Step 8: Pre-test. Use special detection tools (different equipment for COBs with different uses, the simple one is a high-precision voltage-stabilized power supply) to detect the COB board and rework the unqualified boards.
Step 9: Glue dispensing. Use a glue dispensing machine to apply an appropriate amount of the prepared AB glue to the bonded LED crystal, and the IC is encapsulated with black glue, and then the appearance is encapsulated according to customer requirements.
Step 10: Curing. Place the sealed PCB in a heat cycle oven and keep it at a constant temperature. Different drying times can be set according to requirements.
Step 11: Post-test. Use a dedicated testing tool to test the electrical performance of the packaged PCB to distinguish good from bad.