Detailed interpretation of the manufacturing process of LED chips

The manufacturing process of the LED chip can be roughly divided into several steps such as a wafer processing process (Wafer FabricaTIon), a wafer needle testing process (Wafer Probe), a packaging process (Packaging), and a test process (IniTIal Test and Final Test). The wafer processing step and the wafer needle measurement step are the front end steps, and the assembly process and the test process are the back end processes.

1, wafer processing process

The main work of this process is to make circuits and electronic components (such as transistors, capacitors, logic switches, etc.) on the wafer. The processing procedure is usually related to the product type and the technology used, but the general basic procedure is to first properly apply the wafer. After cleaning, oxidation and chemical vapor deposition are performed on the surface, and then repeated steps such as coating, exposure, development, etching, ion implantation, and metal sputtering are performed, and finally, several layers of circuits and components are processed and fabricated on the wafer.

2, wafer needle testing process

After the previous process, a small grid, ie, a die, is formed on the wafer. Generally, in order to facilitate testing and improve efficiency, the same type and specification of products are produced on the same wafer; Need to make several products of different varieties and specifications. After measuring the electrical characteristics of each die with a probe, and marking the unqualified die, the wafer is cut into individual grains and then electrically characterized. Classification, loading into different trays, and rejecting unqualified grains.

3, the assembly process

That is, a single die is fixed on a plastic or ceramic chip base, and some lead terminals etched on the die are connected with the pins protruding from the bottom of the base to be connected to the external circuit board. Finally, cover the plastic cover and seal it with glue. Its purpose is to protect the crystal grains from mechanical scratches or high temperature damage. At this point, we have made an integrated circuit chip (that is, those black or brown that we can see in the computer, rectangular blocks with many pins or leads on both sides or four sides).

4. Test procedure

The last process of chip manufacturing is testing. It can be divided into general test and special test. The former is to test the electrical characteristics of the packaged chip under various environments, such as power consumption, running speed and pressure resistance. The tested chips are classified into different grades according to their electrical characteristics. The special test is based on the technical parameters of the customer's special needs, take some chips from the similar parameter specifications and varieties, and do specific tests to see if they can meet the special needs of customers to decide whether they need to design special for customers. chip. Products that have passed the general test are affixed with labels of specifications, models, and date of manufacture, and are packaged and shipped. Chips that fail the test are classified as downgrades or scraps depending on the parameters they reach.

LED chip manufacturing process:

Epitaxial wafer→cleaning→plating transparent electrode layer→transparent electrode pattern lithography→corrosion→debonding→platform pattern lithography→dry etching→degreasing→annealing→SiO2 deposition→window pattern lithography→SiO2 corrosion→degraction→ N-pole pattern lithography → pre-cleaning → coating → stripping → annealing → P-pole pattern lithography → coating → stripping → grinding → cutting → chip → finished product test.

LED chip

LED chip manufacturing process

In fact, the production process of the epitaxial wafer is very complicated. After the epitaxial wafer is finished, the next step is to make electrodes (P-pole, N-pole) for the LED epitaxial wafer, and then start cutting the LED epitaxial wafer with a laser machine (previously cutting LED epitaxial wafers are mainly made of diamond knives. After being fabricated into chips, nine points are taken at different positions on the wafer for parameter testing.

1. Test the voltage, wavelength and brightness mainly. The wafer that meets the normal shipping standard parameters will continue to do the next step. If the nine-point test does not meet the relevant requirements, the wafer is placed on one side. deal with.

2. After the wafer is cut into chips, 100% visual inspection (VI/VC), the operator should use a microscope magnified 30 times for visual inspection.

3. The chip is then fully automated, selected, tested, and classified using a fully automated sorter based on different voltage, wavelength, and brightness prediction parameters.

4. Finally, the LED chip is inspected (VC) and labeled. The chip area should be at the center of the blue film. There are up to 5,000 chips on the blue film, but the number of chips on each blue film must be no less than 1000. The chip type, batch number, quantity and photoelectric measurement statistics are recorded on the label. Attached to the back of the glossy paper. The chip on the blue film will be the same as the first visual inspection standard, ensuring that the chips are neatly arranged and of good quality. This makes LED chips (currently known as square chips on the market). In the process of manufacturing the LED chip, some defective or electrode-worn chips are separated, which are the latter crystals. At this time, there are some wafers on the blue film that do not meet the normal shipping requirements. Become a side piece or a piece of hair.

Just mentioned that nine points are taken at different positions on the wafer for parameter testing. For wafers that do not meet the relevant requirements, these wafers cannot be directly used as LED squares, and therefore do not do anything. After the inspection, it was sold directly to the customer, which is the LED wafer on the market (but there are also good things in the big wafer, such as square chips).

Different Connector Pigtail

Divide an optical jumper into two to become two optical pigtails.
The optical jumper refers to the optical connection line with the optical fiber movable connector installed at both ends of the optical fiber or optical cable. It is usually used for fiber patching or switching in distribution equipment or between optical equipment, and the length is usually no more than 10 meters.
It is a popular and common saying in the industry that when the connecting wire is an optical cable (indoor optical cable), it is called an optical fiber jumper, and when the connecting wire is an optical fiber, it is called an optical fiber jumper.
In mobile communications, coaxial cable jumpers have special product standards, while optical jumpers are different. Optical jumpers do not have special product standards. Because the attenuation of optical fibers is very small, and the length of optical jumpers is not long, the optical fiber attenuation is negligible. Therefore, the optical fiber movable connector standard is also used as the optical patch cord standard in practice. Some content of the optical fiber movable connector is different from the optical patch cord. However, in the long run, the industry has already considered the optical fiber movable connector standard That is, it is the standard for optical patch cords.

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