According to some embodiments of the invention, there is provided line photo masks that includes transistors having reinforcement layer patterns and methods of forming the same. The transistors and the methods provide a way of compensating a partially removed amount of a strained silicon layer during semiconductor fabrication processes. To the end, at least one gate pattern is disposed on an active region of a semiconductor substrate. Reinforcement layer patterns are formed to extend respectively from sidewalls of the gate pattern and disposed on a main surface of the semiconductor substrate. Each reinforcement layer pattern partially exposes each sidewall of the gate pattern. Impurity regions are disposed in the reinforcement layer patterns and the active region of the semiconductor substrate and overlap the gate pattern. Spacer patterns are disposed on the reinforcement layer patterns and partially cover the sidewalls of the gate pattern.