Study on the process of laser marking for silicon wafer by 1060nm-MOPA laser

Abstract

The silicon material is very sensitive to the change of the laser, and a small change in energy will cause a relatively large change in the morphology of the mark. Therefore, it is a great challenge to produce uniform and high-quality laser marks on silicon wafers. A new Master Oscillator Power-Amplifier (MOPA) fiber laser with independently adjustable pulse width and frequency have a wide adjustable parameter window. In this paper, a new type of MOPA fiber laser is used to study the marking process on silicon wafers. By changing average power (defined by the active current set point), pulse repetition frequency (PRF) and pulse duration of the laser (i.e., the number of pulses), dot matrix marking on the wafer, using the Keyence VHX-6000 optical microscope to determine the cleanliness and surface topography of the wafer surface to evaluate. Studies have shown that the influence of the output instability of the fiber laser on the marking quality can be reduced by increasing the number of pulses under the condition of stable and low power. At the same time, the resolution of the single pulse energy of the laser is improved by changing the laser PRF, and then the control precision of the energy is improved, so as to realize the high-quality silicon wafer laser marking process with uniform and stable marking morphology.