Compared with the traditionally manufacture of single mesa diode wafer which has some disadvantages such as low speed and high chipping rate of blade-sawing, laser scribing is of high yield rate because of non-contact processing. According to the properties of crystal silicon (Si), the direction of the scribing and its mechanism of Si processed by infrared (IR) laser are discussed. On the base of approximate analytical solution derived from one-dimensional heat conduction equation, the ablation depth influenced by laser power and scanning speed is calculated. 7.62 cm wafer scribed under the condition of 1064 nm pulsed fiber laser shows that chipping rate is less than 1% and eligible electrical properties attain 100%. Research shows that ablation depth can influence the chipping rate and defocusing amount can influence the electrical properties of the chip. High yield rate can be achieved by controlling the ablation depth and defocusing amount during the scribing.