The quality of the LED chip directly determines the level of LED performance. In the LED pre-process process, complex processing steps such as cleaning, evaporation, yellow light, and chemical etching inevitably cause defects in the chip. For example, during the evaporation process, the chip is fixed by using a spring clip and produces a pinch mark; in the yellow light operation, if the development is incomplete or the mask is broken, the residual metal will be in the light emitting area of the chip.
Therefore, in order to ensure the quality of the chip, in the LED pre-process process, it is necessary to conduct defect detection on the LED chip to ensure the product yield of the post-process process and improve the production efficiency.
LED front process
Chip detection first adopted the method of manual visual inspection, but with the gradual improvement of LED lighting and display industry technology, the miniaturization trend of packaged devices puts forward more stringent requirements for chip detection. The increased difficulty of manual visual inspection, the increase in the false positive rate, and the inability to detect certain types of defects can no longer meet the testing requirements of the market. Automatic optical AOI detection technology can automatically locate and detect LED chips, which can effectively reduce the labor intensity of workers, reduce the detection false positive rate, and greatly improve work efficiency, saving a lot of manpower and material costs.
In 2018, Han's Semiconductor entered the vision inspection industry and successfully developed the LED chip AOI Visual Inspection Machine (COT) in 2019. With rich R&D experience and technology accumulation in the field of LED chip testing, and in 2020, we independently developed the LED chip AOI Visual Inspection Machine (COW), taking the lead in breaking the technical monopoly of foreign companies on the equipment, and successively being highly recognized by industry benchmark customers, and the sales of equipment continued to grow.
LED chip AOI visual inspection machine (COW)
Device appearance diagram
AOI (Automatic Optic Inspection) wafer inspection equipment is mainly used in Wafer appearance defect detection, using advanced combined light source lighting technology and high-speed high-resolution camera, can clearly identify Wafer's appearance defects, configure high-resolution lenses with different magnifications, and detect a minimum defect size of about 2μm.
Equipment advantages
◆ Instead of manual testing, stable work efficiency: automatic detection and display of test results, fast detection speed and stable and reliable detection, reduce the impact of human factors;
◆ Realize data, the work process can be completely recorded: the digital intelligence of the machine will keep all the production records, ensuring the quality traceability of the production process;
◆ With pre-positioning function: before entering the detection area, the position of the wafer on the material tray can be pre-positioned, saving the overall detection time;
◆ Save labor costs: the barrel is placed around the wafer robot, the handling operation is not stopped, and the loading and unloading area can accommodate a total of 7 * 25 pieces. With intervals of more than 1.5h, one person can manage multiple machines at the same time.
Test samples
Test example 1
Test example 2
Test example 3
Han's Semiconductor has a number of patents in the field of optical sensing and dimensional measurement, and has professional design, research and development and production capabilities of vision and laser scanning detection algorithms, motion control systems and optical measurements. Han's Semiconductor will continue to promote the research and development and optimization of key technologies for ultra-high-precision automatic optical inspection, and maintain an attitude of excellence, provide customers with fast, accurate and stable automated inspection solutions and process information quality management systems, and strive to achieve the goal of full coverage of visual inspection equipment in the pan-semiconductor industry.