Research On Silicon Wafer Dicing Technology

In the semiconductor industry,the silicon substrate occupy an absolute dominant position and are widely used in MEMS devices,memory,central processing unit,power devices and other products.Wafer die is getting smaller and thinner.The disadvantages of traditional diamond saw equipment appears,so the laser dicing technology is wildly used for silicon dicing.In this paper,we research on two kinds of laser cutting technology,including the stealth dicing and ablation dicing,and the best cutting technology for different types of silicon wafers was discussed.The main research is as follows:(1)research on laser stealth dicing technology.The influence of laser power,such as frequency,cutting speed,overlapping rate,focal position and cutting frequency on the quality of silicon wafer cutting was studied.The silicon wafer below 0.2mm,can be cut by one watt.As the thickness increases,the number of dicing times needs to be increased.After the cutting is completed,the back and front of the silicon chip will be cracked by 1-2microns,and then each dies will be completely separated by expansion.(2)research on laser ablation dicing technology.The effects of laser ablation,such as laser power,focal position,speed,spot overlap rate,focal position,etc.were studied.we use 355 nm laser for cutting,cooperate with the focusing lens to complete the processing of various thickness of silicon ablation dicing power is not very strict boundaries,2 Watts is suitable for cutting the focal point of power,and efficiency of both the collapse edge,when increase of power,micro cracks and collapse edge will increase,if the power gradually decreases,edge crack will also decrease,but the efficiency is lower,when the power is less than 1 watt,cutting becomes very difficult due to the sidewall absorption.The results show that the laser stealth cutting and laser ablation cutting each have advantages and disadvantages,stealth cutting is suitable for the processing of pure silicon or pure silicon cutting,and ablation dicing is suitable for all kinds of structures.