Research Of Optical Tsv And Coupling Characteristics Based On 3D Optoelectronic Integration

With the shrinking size of transistors,signal transmission delay and cross-talk noise caused by interconnection effects have become bottlenecks that limit the performance of integrated circuits.3D integration technology provides a solution to the interconnection problem.Through-Silicon Vias(TSV)technology is the key technology for 3D integration,which realizes the vertical interconnection of circuit modules,thus shortening the interconnection length and improving the interconnection density.However,the parasitic effect still exists in traditional electrical TSV interconnection.As an alternative to electrical interconnection,optical interconnection has many advantages,such as low power consumption,small delay,large bandwidth and strong anti-interference ability,which attracts the attention of many researchers.TSV and on-chip optical interconnection technology provide the necessary conditions for optical TSV interconnection.Optical TSV interconnection is a new type of interconnection.It combines the advantages of three-dimensional integration and on-chip optical interconnection,so that the performance and area of integrated circuits can be significantly optimized.This paper focuses on the key issues of optical TSV interconnection.Firstly,the propagation characteristics of optical TSV are studied by using Beam Propagation Method(BPM).The optical TSV with silicon core is modeled by Rsoft software,and the influence of light source size and alignment on the transmission characteristics of optical TSV is studied.The optical TSV with rough sidewall is simulated,and the influence of sidewall roughness on the loss of optical TSV with different core diameters is studied.Under the same roughness of 0.2 ?m,the loss of optical TSV with 7 ?m core diameter and 15 ?m core diameter is 3.9 d B/mm and 0.4 d B/mm respectively,which indicates that the smaller size,the more sensitive the scattering loss is to the side wall roughness.The simulation of optical TSV with inclined sidewall is carried out,and the loss of the inverted trapezoidal and trapezoidal structured optical TSV are discussed.The loss of TSV of inverted trapezoidal structured is 4.2 d B/mm and that of TSV of normal trapezoidal structured is 3.1 d B/mm when the inclination is the same as 1 degree.Secondly,the coupling characteristics of optical TSV are studied by using Finite Difference Time Domain(FDTD).The coupling structure of TSV and grating is modeled by Rsoft software,and the coupling efficiency of grating structure with reflector in buried oxygen layer is studied.The key parameters of grating structure are simulated and analyzed.The effects of grating period,etching depth,duty cycle and mirror position on the coupling efficiency are deeply studied.The simulation results show that the coupling efficiency of grating with a period of 561 nm,etching depth of 70 nm and duty cycle of 50% is up to 34% at 1550 nm wavelength.Finally,the factors of coupling loss between optical TSV and grating are analyzed,and the coupling structure is improved.In order to solve the problem of light leaking to the optical TSV cladding,the cladding with mirrors on the end of the optical TSV are designed,which increases the coupling efficiency to 45%.Moreover,the coupling structure of reflecting grating or DBR on the side of the coupled grating is further designed to realize the unidirectional vertical coupling between the optical TSV and the grating,and the coupling efficiency is up to 70% and 80% respectively.