Reliability of MSQ spin-on glass as low-k interlayer dielectric in VLSI device

There has been increasing trend to reduce the size of VLSI device dimension for speed improvement. However, another trend to improve the speed is to reduce the parasitic RC that exists in a VLSI device. Low-k dielectric thin film acting as interlayer dielectric is used to reduce the parasitic capacitance between metal layers. There are two main types of low-k dielectric based on the deposition method; i.e. spin-on and chemical vapor deposition. In this paper, the reliability problem due to metal diffusion of spin-on glass type low-k dielectric called methylsilsesquioxane (MSQ) is discussed. The results also showed that the method of metal deposition does affect the diffusion through the MSQ layer due to differences in thermal energy for each deposition method and therefore affecting the reliability of this thin film to act as a dielectric.