Improved silicon slice laser cutting reduction process

Abstract

The invention relates to an improved silicon slice laser cutting reduction process, which can ensure the cutting quality of a silicon slice, improve energy output and lower production cost. The reduction process comprises backside grinding and laser cutting working procedures, and is characterized in that the laser cutting working procedure is carried out on the silicon slice firstly, and then the backside grinding is carried out on the silicon slice.

Description

technical field [0001] The invention relates to the technical field of laser cutting of silicon wafers, in particular to an improved silicon wafer laser cutting thinning process. Background technique [0002] At present, the cutting of silicon wafers mainly adopts the mechanical diamond cutting method. In this cutting method, the diamond blade cuts the block part of the wafer at a high speed of 30,000 to 40,000 revolutions per minute, and at the same time, carries the work of the wafer. The table moves in a straight line at a certain speed along the tangential direction of the contact point between the blade and the wafer. The silicon chips generated by cutting the wafer are washed away by deionized water. The thicker the cut silicon wafer, the slower the cutting speed. In order to increase the production capacity , the silicon wafer is often back-ground to reduce the thickness of the silicon wafer to a corresponding thickness, and then the silicon wafer is cut; in addition,...

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Problems solved by technology

[0002] At present, the cutting of silicon wafers mainly adopts the mechanical diamond cutting method. In this cutting method, the diamond blade cuts the block part of the wafer at a high speed of 30,000 to 40,000 revolutions per minute, and at the same time, carries the work of the wafer. The table moves in a straight line at a certain speed along the tangential direction of the contact point between the blade and the wafer. The silicon chips generated by cutting the wafer are washed away by deionized water. The thicker the cut silicon wafer, the slower the cutting speed. In order to increase the production capacity , the back side of the silicon wafer is often ground first, so that the thickness of the silicon wafer is reduced to the corresponding thickness, and then the silicon wafer is cut; in addition, when the mechanical diamond cuts the silicon wafer, the dust pollution is serious

In recent years, silicon wafer laser cutting has gradually replaced the previous mechanical diamond cutting method due to its advantages of zero cutting line loss, no water process, no dust, no static electricity, and fast cutting speed. Laser cutting is based on the surface of silicon wafers and focuses on the At a certain depth, cracks are formed inside the silicon wafer, and then the silicon wafer is separated by expanding the patch. However, when the silicon wafer is back-ground, there will be a problem of uneven thickness, and the thickest and thinnest parts of the silicon wafer surface will appear 5μm With a thickness difference of ~10μm or so, the laser will refract when it enters the silicon wafer from the air, and the thickness difference of the silicon wafer will cause the actual focus point of the laser to shift, thus affecting the cutting quality of the silicon wafer

Although the thickness of the silicon wafer can be controlled by back polishing after the back grinding of the silicon wafer, this method will greatly increase the production cost; it is also possible to measure the surface shape of the silicon wafer first and then make compensation when cutting, but this requires additional laser scanning times, thereby reducing wafer cutting capacity

In addition, after the back grinding of the silicon wafer, due to its thinner thickness, it will increase its fragmentation rate in the subsequent process and increase the production cost.