Microscopic inspection of precision ceramics: Whether there is mechanical damage on the surface of the material and whether the size of the lockhill chip and the size of the electrode meet the process requirements. Whether the electrode pattern is complete. LED chip expansion Because the LED Machinable Ceramic Bushing chips are still closely arranged with a small spacing (about 0.1mm) after dicing, it is not conducive to the operation of the subsequent process. Use a chip expander to expand the film bonding the chips, so that the spacing of the LED chips is stretched to about 0.6mm. Manual expansion can also be used, but it is easy to cause undesirable problems such as chip drop and waste. LED dispensing Apply silver glue or insulating glue to the corresponding position of Macor Ceramics the LED bracket. For GaAs and SiC conductive substrates, red light, yellow light, and yellow-green chips with back electrodes use silver glue. For blue and green LED chips with sapphire insulating substrates, insulating glue is used to fix the chips.
The difficulty of the process lies in the control of the amount of glue, and there are detailed process requirements in the height of the glue and the position of the glue. Since Silicon Nitride Parts silver glue and insulating glue have strict requirements for storage and use, remind: the wake-up, stirring and use time of silver glue are all matters that must be paid attention to in the process. LED glue preparation
Contrary to dispensing, glue preparation is to use a glue preparation machine to first apply silver glue on the back electrode of the LED, and then install the LED with silver glue on the back on the LED bracket. The efficiency of glue preparation is much higher than that of dispensing, but not all products are suitable for glue preparation. LED manual thorns Place the expanded LED chips (with glue or without glue) on the jig of the thorn table, place the LED bracket under the jig, and use a needle to pierce the LED chips to the corresponding positions one by one under the microscope. Compared with automatic racking, manual thorn chips have an advantage, which is easy to replace different chips at any time, and is suitable for products that need to install multiple chips. Automatic LED mounting is actually a combination of two steps: dipping (dispensing) and installing chips. First, put silver glue (insulating glue) on the LED bracket, and then use a vacuum nozzle to suck up the LED chip to move the position. , and then place it on the corresponding bracket position. In the process of automatic racking, it is mainly necessary to be familiar with the operation and programming of the equipment, and at the same time, adjust the glue and installation accuracy of the equipment. In the selection of suction nozzles, try to use bakelite suction nozzles to prevent damage to the surface of LED chips, especially blue and green chips must use bakelite. Because the steel nozzle will scratch the current spreading layer on the surface of the chip. The purpose of LED sintering and sintering is to solidify the silver glue, and sintering requires monitoring of the temperature to prevent batch defects. The temperature of silver glue sintering is generally controlled at 150 ° C, and the sintering time is 2 hours. According to the Silicon Nitride Ceramic Pin actual situation, it can be adjusted to 170℃ for 1 hour. Insulation glue is generally 150 ℃, 1 hour.
The silver glue sintering oven must be opened to Silicon Nitride replace the sintered product every 2 hours (or 1 hour) according to the process requirements, and the middle should not be opened at will. The sintering oven shall not be used for other purposes to prevent pollution.
The purpose of LED pressure welding is to lead the electrodes to the LED chip to complete the connection of the inner and outer leads of the product. There are two types of LED pressure welding processes: gold wire ball welding and aluminum wire pressure welding. The process of aluminum wire Zirconia Ceramic Sleeve pressure welding is to press the first point on the LED chip electrode, then pull the aluminum wire to the top of the corresponding bracket, press the second point and then tear the aluminum wire. The gold wire ball bonding process burns a ball before pressing the first point, and the rest of the process is similar. Pressure welding is a key link in LED packaging technology, and the process is mainly to monitor the shape of the pressure-bonded gold wire (aluminum wire) arch wire, the shape of the solder joint, and the tension.
What are the inspection methods for precision ceramics?
2022 05/16