Laser scribing method reducing chip physical stress damage

Abstract

The invention discloses a laser scribing method reducing chip physical stress damage. According to the technical scheme, the method includes emitting laser to the back of a wafer, and focusing the front surfaces of wafer scribing channels through primary laser scanning; selecting the laser source energy with the set strength, allowing the covalent bonds between the surface crystals of the wafer scribing channels to break completely to obtain an amorphous layer so as to reduce the transmission capability of mechanical stress; performing multiple times of laser scanning in the same scribing channel, and allowing the scanning laser focusing depth to decrease sequentially; allowing the distances between the scanning laser focusing points to be smaller than or equal to the effective bond breaking area radius of the adopted laser source. By the aid of the method, the damage on Flash products with the scribing channels which are smaller than 20 micrometers by laser scribing can be reduced greatly, and the laser scribing can be applied to the Flash products with the scribing channels which are smaller than 20 micrometers in batches. The method is adaptive to the Flash products with the scribing channels which are smaller than 20 micrometers.

Description

technical field [0001] The invention relates to the field of hidden laser scribing of wafers in integrated circuit manufacturing, in particular to a laser scribing method capable of reducing physical stress damage to chips in a laser scribing process method for wafers with a scribing track width less than 20 μm. Background technique [0002] Traditional diamond scribing cannot perform scribing on Flash (flash memory) products with scribing lines smaller than 20 μm. [0003] The laser scribing process method has been widely used and promoted in the fields of LED (light-emitting diode) and RFID (radio frequency identification); however, in the field of Flash products with higher integration, smaller feature size, and lower cost requirements, due to laser scribing Micro-damages caused by thermal stress and physical stress caused by chips can damage Flash products, resulting in a loss of yield that cannot be ignored, and cannot be mass-produced and applied to Flash products, whi...

AI Technical Summary

Problems solved by technology

[0002] Traditional diamond knife scribing cannot perform scribing on Flash (flash memory) products with scribing lines less than 20 μm

[0003] The laser scribing process method has been widely used and promoted in the fields of LED (light-emitting diode) and RFID (radio frequency identification); however, in the field of Flash products with higher integration, smaller feature size, and lower cost requirements, due to laser scribing Micro-damages caused by thermal stress and physical stress caused by chips can damage Flash products, resulting in a loss of yield that cannot be ignored, and cannot be mass-produced and applied to Flash products, which seriously hinders the application of laser scribing in the Flash field. and promotion

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