LED chiplet and LED chip invisible cutting method

Abstract

The present invention relates to the field of LED chip technology, and particularly relates to an LED chiplet and an LED chip invisible cutting method. The LED chiplet is disclosed, wherein the side surface of a substrate of the LED chiplet is provided with a plurality (three or more) of spaced laser scratches along the thickness direction of the substrate, and the side surface of the substrate is arranged in an up-and-down manner along the thickness direction of the substrate. The method is also provided, including a step S1) of forming a plurality of (three or more) laser scratches spaced along the thickness direction of the substrate inside the substrate in a cutting passage by adopting invisible cutting. According to the LED chiplet and the method, the yield of chiplet cutting is increased, substrate inclination is reduced, and the width of cutting passage lines can be reduced, thus increasing the yield from one chip. Side light extraction is increased, the light emitting angle is increased and forward-direction light is increased, thus increasing the brightness of the chiplet.

Description

technical field [0001] The invention belongs to the technical field of LED chips, and in particular relates to an LED chip and an invisible cutting method for LED chips. Background technique [0002] At present, the LED chip is divided into independent LED chips, which is usually completed by forming a single laser scratch inside the substrate through invisible cutting, and then splitting. However, it is easy to cut and grind thicker chips (thickness is generally greater than 150 μm) The following situations occur: (1) Due to the low laser energy used in stealth dicing, twin cells or even multiple cells are prone to occur, and the core particle cutting yield is low; (2) The chip can be split normally, but the laser cutting position and There is a large deviation in the crack position, and the oblique crack is serious. As shown in Figure (1), the line width of the cutting line needs to be increased, otherwise it is easy to damage the light-emitting area and reduce the brightn...

AI Technical Summary

Problems solved by technology

[0002] At present, the LED chip is divided into independent LED chips, which is usually completed by forming a single laser scratch inside the substrate through invisible cutting, and then splitting. However, it is easy to cut and grind thicker chips (thickness is generally greater than 150 μm) The following situations occur: (1) Due to the low laser energy used in stealth dicing, twin cells or even multiple cells are prone to occur, and the core particle cutting yield is low; (2) The chip can be split normally, but the laser cutting position and There is a large deviation in the crack position, and the oblique crack is serious. As shown in Figure (1), the line width of the cutting line needs to be increased, otherwise it is easy to damage the light-emitting area and reduce the brightness; and increasing the line width of the cutting line will cause Reduce the output of LED chips on a single wafer

[0003] In some cases, there is a dicing process that uses stealth dicing on the back and the cutting depth is greater than 1 / 2 of the chip thickness to solve technical problems such as low yield and low brightness caused by oblique cracks.

However, the closer the stealth cutting position is to the epitaxial layer, the electrical failure rate of the LED chip will increase. Therefore, a smaller laser energy must be used to reduce the electrical abnormality, which will lead to an increase in the number of twins or even multiples of the chip, and a decrease in the cutting yield.

[0004] In addition, in order to ensure the normal photoelectric parameters of the chip and take into account the appearance yield after chip splitting, the stealth dicing technology usually applied to LED requires a proper combination of stealth dicing laser energy and laser focus position, so that the laser ablation marks on the side of the chip after splitting can be maintained at Within a certain range, the side of the chip is relatively smooth, so the light emitted from the side of the core particle cannot be collected effectively

Images