Study on Picosecond Pulsed Laser Grooving Technology for Low-k Silicon Wafer

With the continuous reduction of chip manufacturing process, more and more low dielectric constant (low-k) materials are introduced into wafer manufacturing to replace the traditional dielectric material (SiO 2 ). Due to the low mechanical strength and hard and brittle features of low-k materials, it is easy to cause defects such as peeling and topside chipping during blade dicing. Hence the blade dicing is no longer suitable for the product, laser grooving process comes into being. In this study, the influence of key parameters of laser grooving, such as laser power, feed speed and scanning times on the grooving characteristics is researched by the orthogonal experiment. High power optical microscope, OLS5100 are used to inspection in this study. The orthogonal experiment results show that the depth of the groove depends mainly on the laser power and feed speed. The width is greatly affected by scanning times and laser power, and the feed speed has the least effect. The results of single factor experiment show that a higher laser fluence results to higher the groove depth and a larger groove bottom surface roughness under the condition of fixed grooving speed and scanning times, the maximum values can reach 12.493μm and 0.477μm, respectively. Besides groove width is basically unchanged, depending on laser spot diameter.