1. Adhesive film:
(1) Inspection of raw materials before sticking:
① Check the cleanliness of PCB pads with a microscope to ensure that the aluminum wire PCB pads are firmly in contact during wire bonding. If
The PCB pads are not clean, and the aluminum wires at the end of the PCB pads may curl up, causing abnormal display. The measure taken is to wipe with an eraser and then blow off the rubber residue with an air gun.
② Use a microscope to check for silicon slag inside the chip, with the aim of removing the silicon slag inside the box and protecting the chip. If there is silicon slag inside the box,
During the sticking process, silicon slag can scratch the chip, damage the circuitry on the chip, and prevent the chip from functioning properly. The measure taken is to use adhesive sticks to stick out the silicon slag.
(2) Adhesive process parameters:
① Glue size:
The dispensing size is 1.5mm in diameter. The dispensing amount should be moderate, as too much can easily soak the chip, causing the aluminum wire to not come into contact with the chip; too
If there is a shortage, the chip will not stick firmly and will detach from the PCB during the wire bonding process.
② Drying temperature:
The drying temperature is 100 ℃± 5 ℃. The temperature should not be too high, as the maximum storage temperature of the chip is 135 ℃. Excessive temperature can damage the chip. Of course, the temperature should not be too low, as it will prevent the adhesive from curing. The chip will loosen and fall off during the wire bonding process.
③ Drying time:
The drying time is 7 minutes ± 2 minutes. The time cannot be too short, otherwise the adhesive will not have enough time to cure. Placement of chips on PCB
Attention should be paid to the position and direction, and it should be level and straight. If not aligned, aluminum wires will come together during the welding process, causing a short circuit.
2. Pressure welding:
Aluminum wire does not only need to make contact with chip pads and PCB pads to achieve its purpose, but also requires firm contact points, that is
Can withstand a certain amount of force. The precautions for pressure welding are:
① The alignment of pressure welding must be accurate, otherwise the solder joints may be misaligned or even deviate from the chip pads, affecting the display effect.
② When resuming production of products that have already been produced, the program should be calibrated to ensure that the machine is in its current working state,
Still able to accurately press weld.
③ Before starting the welding process, check the accuracy of the machine's confirmation of the welding points through the screen welding method. Only when
Production operations can only be carried out when the machine can accurately identify the position of the solder joint.
④ After the machine starts working, it is not allowed to move the PCB on the workbench fixture again.
3. Testing:
① According to the process card requirements of this product, connect the testing tool to the power supply, depending on whether the LCD screen is TN or STN type
Select the voltage value to be adjusted.
② The display content is complete, the program runs from beginning to end, and each screen must be checked without any omissions.
