The present invention aims at providing: a material for forming an adhesion reinforcing layer which can reinforce the adhesion between a low dielectric constant film, especially a low dielectric constant film containing an inorganic material, and other members; an adhesion reinforcing layer formed by the said material and exhibits superior adhesion; a fast and highly reliable semiconductor device having the adhesion reinforcing layer; and a manufacturing method thereof. The material for forming an adhesion reinforcing layer contains at least any one of organoalkoxysilane having a basic functional group, a basic additive and organoalkoxysilane. The adhesion reinforcing layer is formed by the said material. The manufacturing method of a semiconductor device includes a process for forming a low dielectric constant film and, at least before or after the process for forming a low dielectric constant film, a process for forming an adhesion reinforcing layer with the said material.