Solar panels have been developed to convert the solar energy to electricity. Since most solar panels are silicon based, they inherit the mechanical properties of silicon, such as brittleness and hardness. These properties might lead to cracking in workpieces and low tool lives in traditional machining processes. In solar panel manufacturing, to increase the efficiency of solar cells, electrical contacts on the front side of the panel need to be connected to those on the back side. Therefore, holes of different sizes are required to drill in silicon solar panels for certain designs. This paper reviews the literature on different drilling processes for silicon solar panels and summarizes merits, shortcomings, and special characteristics of each method.