Chip manufacturing
Epitaxial growth
This is the basic step in LED chip manufacturing. Metal organic chemical vapor deposition (MOCVD) technology is usually used to grow semiconductor epitaxial layers on substrate materials (such as sapphire, silicon carbide, etc.). Taking gallium nitride (GaN)-based LEDs as an example, by precisely controlling parameters such as the flow rate, temperature and pressure of the reaction gas, a multilayer structure such as a buffer layer, an unintentional doping layer, an N-type layer, an active area and a P-type layer is grown on the substrate in sequence. The quality and performance of these epitaxial layers directly affect the luminous efficiency and stability of the LED chip.
Photolithography and etching
The designed pattern is transferred to the epitaxial layer using photolithography technology. First, a layer of photoresist is applied to the surface of the chip, and then exposed through a mask to cause chemical changes in the photoresist at a specific pattern. The unnecessary photoresist is then removed through the development process, leaving a photoresist mask of the desired pattern. Then, an etching process such as dry etching or wet etching is used to remove the epitaxial layer material that is not protected by the photoresist to form precise electrode contact holes, isolation grooves and other microstructures.
Electrode preparation
Electrodes are made on the surface of the chip, usually using physical vapor deposition (PVD) methods such as evaporation and sputtering to deposit metal layers such as gold, silver, nickel, etc. The metal layer is patterned through photolithography and etching processes to form an electrode structure connected to the internal circuit of the chip, so that the chip can be connected to the external circuit later.
Packaging link
Stent preparation
The commonly used stents for LED packaging include plastic stents and ceramic stents. Plastic stents have the advantages of low cost and easy molding, while ceramic stents have better heat dissipation performance. First, the stent material is made into a stent structure of a specific shape through processes such as injection molding or sintering, and then the stent is surface treated, such as silver plating, to improve the conductivity and welding performance of the electrode.
Chip pasting
Use adhesive materials such as silver glue to accurately place the LED chip at the specified position of the stent, and heat and cure the chip to firmly bond it to the stent to ensure good electrical connection and mechanical stability between the chip and the stent.
Wire bonding
Use metal wires such as gold wire and aluminum wire as bonding wires, and connect the electrodes on the chip with the pins on the bracket through methods such as hot pressing welding and ultrasonic welding to realize the transmission of electrical signals between the internal circuit of the chip and the external circuit.
Packaging material filling
In order to protect the chip from the influence of the external environment and improve the reliability and stability of the LED, after the chip and wire bonding are completed, it is necessary to fill the bracket with packaging materials. Commonly used packaging materials are epoxy resin, silicone, etc. After heating and melting, the packaging material is injected into the bracket, and it is cured to form a protective shell for the chip.
Finished product testing and sorting
Electrical performance test
Use special testing equipment to test the electrical performance of the packaged LED bulb, mainly detecting its forward voltage, reverse leakage current and other parameters to ensure that the product meets the design requirements and relevant standards.
Optical performance test
Accurately measure the optical parameters of the LED, such as luminous flux, luminous intensity, and light color. Collect the light emitted by the LED through equipment such as an integrating sphere system, and use instruments such as a spectrometer to analyze its spectral characteristics to evaluate the luminous performance and quality of the LED.
Sorting
LED bulbs are classified according to performance parameters based on the test results. For example, they are classified according to the size of luminous flux, consistency of luminous color, etc., to ensure that the performance of LED bulbs in the same batch or the same package is relatively stable and consistent to meet the needs of different customers and application scenarios.
Bulb assembly
Drive circuit integration
LEDs require a suitable drive circuit to provide stable current and voltage to ensure normal light emission and extend service life. Electronic components such as driver chips, capacitors, and resistors are welded on the printed circuit board (PCB) to form a drive circuit module, and debug and test to ensure good performance of the drive circuit.
Overall assembly
The tested and sorted LED chips or packaged LED devices are assembled with the drive circuit module, and then combined with optical components such as reflective cups and lenses, fixed and packaged according to different lighting design requirements, and finally a complete LED bulb product is formed.
Post time: Mar-19-2025
