Three-dimensional modeling of multichip module interconnects

• Published in: IEEE transactions on components, hybrids, and manufacturing technology hybrids, and manufacturing technology, 1993-11, Vol.16 (7), p.699-704
• Main Authors: Cheung-Wei Lam, Ali, S.M., Nuytkens, P.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Conductors; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Finite difference methods; Lithography; Microstrip; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Multichip modules; Reflection; Scattering parameters; Stripline; Time domain analysis; Transmission line discontinuities
• ISSN: 0148-6411; 1558-3082
• DOI: 10.1109/33.257864

The finite-difference time-domain method with nonuniform grid is applied to the analysis of novel three-dimensional (3D) multichip module (MCM) interconnects. The vertical interconnects involved in this technology consist of small plated via holes defined by a photolithography system. The via dimensions are of the same order as the microstrip and stripline linewidths to reduce the transmission line discontinuities. Two 3D transitions are investigated: 1) microstrip-via-stripline and 2) microstrip-via-90 degrees stripline. Electric field distributions and pulse propagation under the microstrip and the stripline are presented. The scattering parameters for various cases are calculated and compared. Geometrical effects such as different conductor extensions on top of the vias and different hole sizes in the reference plane are also investigated. It is found that the 90 degrees bend structure shows less reflection than the straight one. Designers may introduce such 90 degrees bends intentionally to improve signal transmission.< >