Photoelectric property detection method for LED crystal grains

Abstract

The invention provides a photoelectric property detection method for LED crystal grains. The photoelectric property detection method comprises the following steps: 1) correcting all machines by usinga unified standard sheet, appointing at least one machine as a standard machine, setting expansion ratio parameters, and setting the rest machines without setting the expansion ratio parameters as working machines; 2) in a non-expansion state, placing the wafer cut into the crystal grains on a working machine to obtain detection data, and reckoning the positions of electrodes on the crystal grainsby utilizing the positions and side lengths of the crystal grains during detection; 3) carrying out expansion processing on the wafer, transferring the wafer to a standard machine, and carrying out spot test again to obtain standard data; and 4) comparing the detection data with standard data, correcting the system processing data of which the error does not exceed 3% according to a spot test value, judging that the working machine for detecting the wafer is abnormal if the error is more than 3%, and sending an alarm to an engineer at the same time. According to the photoelectric property detection method, the steps of expanding and scanning the wafer during detection are canceled, and the consistency management and control of products are realized.

Description

technical field [0001] The invention relates to the technical field of LEDs, in particular to a method for improving the detection speed of the photoelectric properties of LED grains. Background technique [0002] Before LED grains are made into light-emitting diodes, they have to go through photoelectric performance testing and sorting processes. Among them, the photoelectric performance test is mainly to test the voltage (VF), wavelength (WD), brightness (LOP) and antistatic ability (ESD) of all LED grains one by one through a photoelectric testing machine, and then determine The actual parameters of each batch of products provide accurate information of products to customers who purchase chips in the future. [0003] The current LED grain detection mainly adopts the traditional method: firstly, the LED wafer is cut into individual grains, and then the distance between adjacent grains is expanded to 1.2 times of the original, which is the most standard LED grain voltage. ...

AI Technical Summary

Problems solved by technology

[0005] Since wafers of different sizes correspond to different expansion ratios during inspection, it is necessary to reset the expansion ratio parameters of all machines when processing different batches of products, and the large number of machines not only causes Waste of time, and extremely prone to expansion ratio input errors

[0006] In addition to the above-mentioned human errors, due to certain errors among different machines, even though all machines were calibrated with a unified standard film before testing, it is still impossible to completely avoid abnormalities in the work of the machines. Considering At present, there is still no effective feedback method for whether the machines are working normally. Therefore, even if some machines are abnormal, it is difficult to be found in time, resulting in the products purchased by customers mixed with defective products, causing subsequent returns and even economic compensation.

[0007] The working principle of the photoelectric testing machine is to use the probe to light up the two positive and negative electrodes on the die, so the actual position of the electrode on each die must be clear during the detection process, and the die in the wafer after expansion (Except for the origin grain) the position changes, so the position of the electrode on the grain also changes, which requires scanning the entire grain array one by one, which takes a lot of time, and the expansion of the wafer also leads to the detection mechanism The total moving distance is greatly increased. For example, it takes at least 10 minutes to scan a 4-inch wafer product, which seriously affects the overall efficiency of photoelectric inspection.

[0008] To sum up, the existing LED grain detection method has the problem of low efficiency, and it is difficult to ensure the consistency control and timely feedback of the test results of many machine products

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