Firstly, the silicon wafer placement point is covered with thermal conductive epoxy resin (usually silver doped epoxy resin) on the substrate surface, and then the silicon wafer is indirectly placed on the substrate surface. Heat treatment is carried out until the silicon wafer is firmly fixed on the substrate, and then wire welding is used to indirectly establish an electrical connection between the silicon wafer and the substrate. The sealing and dismantling process is as follows:
Step 1:crystal expansion: Use an expansion machine to evenly expand the zero speed LED chip film provided by the manufacturer, so that the LED grains closely arranged on the film surface are pulled apart, making it easy to prick crystals.
Step 2:Back glue: Place the expanded crystal ring on the back glue machine surface that has not been scratched with the silver paste layer, and apply the silver paste on the back. Point the silver paste. Suitable for disassembling LED chips. Use a dispensing machine to apply an appropriate amount of silver paste onto the PCB printed circuit board.
(相关资料图)
Step 3: Place the prepared silver paste expansion ring on the spinel frame. The operator will use a spinel pen to prick the LED chip onto the PCB printed circuit board under a microscope.
Step 4: Place the PCB printed circuit board that has been punctured into a dust-free drying oven: Place the PCB printed circuit board outside the oven at constant temperature and let it sit for a period of time. After the silver slurry solidifies, remove it (do not leave it for a long time, otherwise the LED chip coating will turn yellow and oxidize, making it difficult to bond). If there is no LED chip bonding, the above steps are required; If only the IC chip is bound, cancel the above steps.
Step 5: Stick the chip: Use a glue dispenser to place 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 (solid air suction pen or female) to accurately place the bare IC chip on the red glue or black glue.
Step 6 Drying: Place the bonded bare sheet outside the thermal cycling oven and place it on a large flat heating plate at a constant temperature for a period of time, which can also naturally solidify (for a longer time).
Step 7 Bonding (Wiring): Use an aluminum wire bonding machine to bridge the aluminum wires of the corresponding solder pads on the PCB board of the chip (LED grains or IC chips), that is, to weld the inner leads of the COB.
Step 8 Pre test: Use a common testing tool (there are no different equipment for different purposes of COB, simply high-precision voltage stabilizing current) to test the COB board, and repair the unqualified 9 Gluing: Use a dispensing machine to apply an appropriate amount of AB glue to the LED grains prepared by bonding, and seal the IC with black glue. Then, perform appearance sealing according to customer requirements.
Step 10 Curing: Place the sealed PCB printed circuit board into a dust-free drying oven and let it sit at a constant temperature. Different drying times can be set according to requirements.
Step 11 post test: Use a common testing tool to test the electrical performance of the sealed and disassembled PCB printed circuit board, distinguishing between good and bad. With the advancement of technology, there are aluminum substrate COB packaging and COB ceramics for packaging.
Both the fourth and sixth steps above require our dust-free drying oven, which has excellent sealing performance and is used for drying, heat treatment, aging, and other high-temperature tests of non volatile and non flammable and explosive materials. And it can quickly deoxygenate or cool down, which helps to improve product quality. It can meet the requirements of dust-free drying in departments such as electronics, healthcare, instrumentation, factories, universities, and scientific research. The specific parameters are as follows:
1. Oxygen concentration: ≤ %;
2. Temperature range: RT (room temperature)+50~+300 ° C;
3. Temperature deviation: ≤+ ° C;
4. Heating rate: ≥ 5C/min (average throughout the process);
5. Power supply: AC220V 50HZ 3KW;
6. Box material: The outer box is made of SS41 # medium carbon steel plate, which is treated with phosphate film salt and then coated with two layers of anti gloss paint;
7. Inner chamber material: SUS304 # non magnetic mirror stainless steel;
8. Thermal insulation material: superfine Glass wool;
9. Exhaust port: 50;
10. Temperature control system;
11. Temperature measurement sensor: Pt100 platinum resistance;
12. Control instrument: imported digital temperature controller, PID adjustment, control accuracy of ° C;
13. Overtemperature protection instrument: an overtemperature protection system independent of the main control of the studio, ensuring the safety and safety of the test object;
14. Control system: the main electrical components are imported from Snyder, Omron, etc;
15. Partition: 2-layer, stainless steel square tube, with a load capacity of approximately 30KG;
16. Air circulation device: large capacity axial flow motor;
17. Heating method: stainless steel electric heater.
关键词：
