How does the mass of the substance effect the specific heat value?
Specific heat is defined as amount of heat per unit mass of substance that is needed in order to increase the temperature of the substance by one degree celsius.
Mass of the substance has no effect on specific heat, as it is already a quantity expressed per unit mass.
It's a bit like saying "how does the volume of your sample of metal affect the density?" - answer: it doesn't because density is already expressed as a quantity per unit volume.