Control and countermeasures of wafer cracking in LED solid crystal manufacturing process
Single-electrode chips have very high requirements for solid crystal in the packaging industry. For example, in the LED production process, the quality of solid crystal affects the quality of LED finished products. There are many factors that cause LED solid crystal cracking. We only discuss the solution of LED solid crystal cracking from three aspects: materials, machinery, and human factors.
1. The chip material itself cracks
When the chip damage is greater than 1/5 of the width of the single-sided chip or the damage is at an oblique angle, the length of each side is greater than 2/5 of the chip or the aluminum pad is damaged. . The main causes of undesirable phenomena are:
1. Improper operation of chip manufacturers
2. The chip incoming inspection is not spot-checked
3. Not selected during online operation
Solution:
1. Inform chip manufacturers to improve
2 Strengthen the inspection of incoming materials, rejecting chips with too much damage.
3. When performing online Q inspection, the damaged chip should be picked out, and then the good chip should be replaced.
2. Improper use of LED solid crystal machine
1. Improper machine suction parameters
The nozzle height and solid crystal height of the machine are directly controlled by the parameters in the machine computer. The parameter is large and the suction height is small; the parameter is small and the suction height is large, and whether the chip is damaged or not is directly affected by the parameter of the suction height of the machine. The main reasons for the undesirable phenomenon are: large machine parameters, low hug height, and excessive chip force, resulting in chip damage.
Solution:
Adjust the machine parameters, appropriately raise the height of the nozzle tip or the solid crystal height, adjust the nozzle height in the first Pick Level in the Bond head menu of the machine SETUP mode, and then adjust the solid crystal height in the second Bond Level.
2. The size of the nozzle does not match
Chips of different sizes use different nozzles to solid crystal. Large chips use small nozzles, and the chips cannot easily suck up. Small chips use large nozzles, and the chips are easy to break. Therefore, the selection of appropriate suction nozzles is the prerequisite for fixing the chip. The cause of the undesirable phenomenon is that the suction nozzle is too large and breaks the chip.
Solution: Choose the appropriate porcelain nozzle.
3. Artificial improper operation caused rupture
A. Improper operation
Failure to operate according to regulations, resulting in chip breakage. The main causes of undesirable phenomena are:
1. The material is not properly handled and falls to the ground.
2. Encounter chips when entering the oven
Solution: When holding the material, hold your hand firmly. When entering the oven, the material should be flat and gently put in, and it should not be tilted or forced too hard.
B. Heavy object crush
The chip was broken due to excessive force. The main reasons for this bad phenomenon are:
1. The microscope drops onto the material, so that the chip is broken
2. The machine parts drop onto the material.
3. Press the iron plate to the material
Solution:
1. Microscope screws should be tightened
2. Regularly check the machine parts for looseness.
3. There should be no objects such as iron plates on the material.
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