With the increasing power density of integrated circuit packages, the thermal management issue has become one of the most critical issues, and the microchannels is one of the potential methods for heat dissipation. In this paper, four types of Y-shaped microchannels are designed for fan-out packages. The FEM simulations have been conducted to calculate the temperature distribution and pressure drop by changing the angle of microfluidic channels and water flow velocity. Thus, the heat dissipation effect of microfluidic channels with different structures of the same volume can be investigated. Due to the nonlinear properties of microchannels, it is difficult to achieve the minimum temperature, pressure drop and temperature uniformity at the same time. For the application of microchannels in practical fan-out packages, design trade-offs and comprehensive analysis are necessary.