Thick-Dielectric Formation and MOSFET Reliability with Spin-Coating Film Transfer and Hot-Pressing Technique for Seamless Integration Technology

The formation of thick dielectrics by the spin-coating film transfer and hot-pressing (STP) technique is proposed for the fabrication of thick multilevel interconnects. Examination of the characteristics of 20-µm-thick dielectrics on 10-µm-thick line-and-space patterns shows sufficient planarization capability with little dependence on pattern density, which enables the fabrication of a double layer of thick interconnects. To investigate the influence of hot pressing in the STP process on LSIs, the hot-carrier degradation of n-channel metal oxide semiconductor field-effect transistors (MOSFETs) was evaluated. The lifetime of transconductance g m of STP samples was estimated to be over ten years, which is the same as that of samples prepared by the conventional technique of spin-coating. Moreover, the lifetime showed no dependence on pressure, temperature in hot pressing and thickness of dielectrics. These results confirm that the STP technique is applicable to the fabrication of thick interconnects and does not damage the underlying MOSFETs.