Optimum Design Of Repeater Insertion In Cu And Carbon Nano-interconnects On Nanochips

With the continuous development of CMOS technology,the feature size of the integrated circuit is scaling down.The problem of large propagation delay and unstable reliability of conventional Cu interconnects technology have become the main limitations in very large-scale integrated chip design.Therefore,new interconnects technology and innovative conductive materials are urgently needed.Carbon nanomaterials are well known for their unique physical properties in the past decades.Their large electron mean free path,high thermal conductivity and strong current carrying density have broad prospects in interconnect technology applications,which can effectively alleviate the challenges that Cu interconnect is facing.In addition,the insertion of repeater will greatly improve the performance of the circuit in the interconnect.Specifically,the propagation delay of the signal will be greatly reduced.Therefore,to quantify these effects,this paper mainly studies the optimization of the number and size of repeater in Cu materials and carbon nanomaterials in integrated circuits in the 7 nm and 14 nm technology nodes.Related content can be divided into the following sections:In the first part,the equivalent equations for equivalent resistance,capacitance,inductance,etc.of Cu and CNT materials are derived.In addition,the distributed equivalent circuit model is also set up.The expression of optimal number and size of repeater insertion is derived,and the influence of the inductor on the design of the integrated circuit buffer is briefly analyzed.In the second part,with considering the contact resistance between carbon nanomaterials and metal electrodes and the influence of dynamic inductance,the optimal number and size of repeater insertion are proposed for the MWCNT interconnect based on the multivariable fitting method.What's more,the propagation delay of the MWCNT interconnect after repeater insertion and the optimal repeater number and size are studied.The relationship between contact resistance and dynamic inductance are also analyzed.In the third part,the optimal repeater design is made for the voltage-mode-signal(VMS)nano-interconnect and the current-mode-signal(CMS)nano-interconnect.The effects of metal-CNT contact resistance and dynamic inductance on the optimal repeater design is studied in detail.Secondly,the feasibility of machine learning neural network in the optimal buffer design of Cu and CNT interconnection is discussed.Finally,two different design schemes are compared.In the fourth part,the optimal repeater designs in the vertical graphene nanoribbons(VGNR)and horizontal graphene nanoribbons(HGNR)interconnects are compared and analyzed.The VGNR and side-contact HGNR interconnects are found to be unaffected by changes in contact resistance,while the optimal number of repeaters in the top contact HGNR interconnect is significantly reduced.It is further disclosed that the catalyst layer required in the growth of VGNR increases the optimum number of repeaters.Therefore,at the advanced technology node,efforts should be made to reduce the thickness of the catalyst layer.In summary,the corresponding circuit modeling for Cu,SWCNT,MWCNT,and GNR interconnects is performed in VMS and CMS.The performance analysis of these modes are conducted.