Provided are a high-quality non-polar/semi-polar semiconductor device with reduced defect density and improved internal quantum efficiency and light extraction efficiency, and a manufacturing method thereof. The manufacturing method is a method for manufacturing a semiconductor device, in which a template layer and a semiconductor device structure are formed on a sapphire substrate having a crystal plane for growing a non-polar or semi-polar nitride semiconductor layer. The sapphire substrate is etched to form uneven patterns, and the template layer including a nitride semiconductor layer and a GaN layer is formed on the sapphire substrate in which the uneven patterns are formed.