The topology optimization problem is generally an ill-posed problem, where the solution is not unique. Because of that, implementation of topology optimization faces complications such as mesh-dependency of the solution, and numerical instabilities. Also, the results obtained by topology optimization are not usually fabrication friendly due to the fine and arbitrary patterns. An effective method that addresses both above mentioned issues consists of imposing a minimum length scale to the resulting structural members. Several approaches to achieve minimum length scale in topology optimization have been proposed in the literature. However, while some problems are solved, others are created or remain unsolved; and the search for better methods continues. In this thesis, we review several prominent approaches and propose a new approach to achieve minimum length scale. We discuss the potential of the new approach for obtaining other fabrication and design constraints, in addition to the minimum length scale constraint. Thus the new approach has the potential of improving the quality of topology optimization in various engineering applications where design constraints must be placed.