Methods for modeling interactions between massively coupled multiple vias in multilayered electronic packaging structures

• US 20030072130A1
• Filed: 05/30/2002
• Published: 04/17/2003
• Est. Priority Date: 05/30/2001
• Status: Active Grant

• Current Assignee: University of Washington, Washington University In St Louis
• Original Assignee: University of Washington
• Inventors: Jandhyala, Vikram, Chen, Houfei, Tsang, Leung, Huang, Chungchi
• Granted Patent: US 7,149,666 B2
• Time in Patent Office: Days
• US Class Current: 361/679
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

Analyzing interactions between vias in multilayered electronic packages that include at least two spaced-apart conducting planes, and multiple vias that connect signal traces on different layers. Voltages at active via ports are represented as magnetic ring current sources, which generate electromagnetic modes inside the plane structure. Substantial electromagnetic coupling between vias occurs. A full-wave solution of multiple scattering among cylindrical vias in planar waveguides is derived using Foldy-Lax equations. By using the equivalence principle, the coupling is decomposed into interior and exterior problems. For the interior problem, the dyadic Green'"'"'s function is expressed in terms of vector cylindrical waves and waveguide modes. The Foldy-Lax equations for multiple scattering among the cylindrical vias are applied, and waveguide modes are decoupled in the Foldy-Lax equations. The scattering matrix of coupling among vias is then calculated for use in determining signal reflection, transmission, and/or coupling in the electronics package.

Claims

1. A method for determining at least one of a signal reflection, a signal transmission, and a signal coupling among vias in a multi-via electronic package, wherein said electronic package comprises a plurality of vias and at least two parallel layers, comprising the steps of:

(a) creating a model of the electronic package as an interior problem and an exterior problem, relative to the at least two parallel layers;

(b) determining parameters relating to the vias and the parallel planes corresponding to the at least two parallel layers for use in solving said interior problem and said exterior problem;

(c) solving the interior problem to determine a first property of the model based on the parameters that were determined;

(d) using the first property and the parameters to solve the exterior problem, to determnine a second property of the model; and

(e) using the second property to determine at least one of the signal reflection, the signal transmission, and the signal coupling among vias in the electronic structure.

2. The method of claim 1, wherein the second property comprises a scattering matrix.

3. The method of claim 1, further comprising the step of determining an equivalent circuit for the electronic package using the first property.

4. The method of claim 3, further comprising the step of analyzing the equivalent circuit with a circuit analysis program.

5. The method of claim 1, wherein the step of solving the interior problem comprises the steps of:

(a) determining exciting waves using dyadic Green'"'"'s function; and

(b) determining an admittance matrix using Foldy-Lax equations.

6. The method of claim 5, wherein the step of determining the admittance matrix comprises the step of relating the exciting waves, incident waves, and scattered waves.

7. The method of claim 5, wherein the step of determining the admittance matrix using the Foldy-Lax equations comprises the steps of:

(a) assuming each via is a cylindrical perfect electric conductor;

(b) decoupling transverse electric waves and transverse magnetic waves at each via; and

(c) separately solving the Foldy-Lax equations for each of a plurality of waveguide modes defined by the at least two layers.

8. The method of claim 7, wherein the step of separately solving the Foldy-Lax equations is simplified by assuming that radii of the vias are sufficiently small to substantially limit harmonic factors of the vias that must be included.

9. The method of claim 7, wherein the step of separately solving the Foldy-Lax equation is simplified by assuming that a separation distance between the substantially parallel layers is sufficiently small to substantially reduce a number of propagating modes for non-near field interactions.

10. The method of claim 1, wherein the first property comprises an admittance matrix.

11. The method of claim 1, wherein the step of solving the exterior problem comprises the steps of:

(a) integrating the first property into the exterior problem by relating a port voltage and a current relative to the vias; and

(b) determining the second property using method of moment and matrix pencil algorithms.

12. The method of claim 1, wherein the second property comprises a scattering matrix.

13. An article of manufacture adapted for use with a processor for use in determining at least one of a signal reflection, a signal transmission, and a signal coupling among vias in a multi-via electronic package, wherein said electronic package comprises a plurality of vias and at least two parallel layers, said article of manufacture comprising:

(a) a memory medium; and

(b) a plurality of machine instructions stored on the memory medium, said plurality of machine instructions when executed by a processor, causing the processor to;

(i) enable a user to input parameters relating to the vias of the electronic package, which is modeled as interior problem and an exterior problem, relative to the at least two parallel layers;

(ii) solve the interior problem of the model of the electronic package to determine an admittance matrix, based on the parameters that were input;

(iii) solve the exterior problem of the model using the admittance matrix, to determine a scattering matrix; and

(iv) use the scattering matrix to determine at least one of the signal reflection, the signal transmission, and the signal coupling among vias in the electronic package.

14. The article of manufacture of claim 13, wherein the plurality of machine instructions, when executed by a processor, further cause the processor to determine an equivalent circuit for the electronic package, using the admittance matrix.

15. The article of manufacture of claim 14, wherein the plurality of machine instructions, when executed by a processor, further cause the processor to analyze the equivalent circuit with a circuit analysis program.

16. The article of manufacture of claim 13, wherein the plurality of machine instructions, when executed by a processor, further cause the processor to input the scattering matrix into a microwave network model for analysis of the electronic package.

17. A system for determining at least one of a signal reflection, a signal transmission, and a signal coupling among vias in a multi-via electronic package, wherein said electronic package comprises a plurality of vias and at least two parallel layers, comprising:

(a) a memory in which a plurality of machine instructions defining an electronic package analysis program are stored;

(b) a user input device;

(c) a display; and

(d) a processor that is coupled to the user input device to receive a user input, to the memory to access the machine instructions, and to the display, said processor executing said machine instructions and thereby implementing a plurality of functions, including;

(i) enabling a user to input parameters relating to the vias and the at least two parallel layers of an electronic package, which is modeled as interior problem and an exterior problem, relative to the at least two parallel layers;

(ii) solving the interior problem of the model for the electronic package, to determine an admittance matrix, based on the parameters that were input;

(iii) solving the exterior problem of the model for the electronic package using the admittance matrix to determine a scattering matrix; and

(iv) enabling a user to use the scattering matrix to determine at least one of the signal reflection, the signal transmission, and the signal coupling among vias in the electronic package.

18. The system of claim 17, wherein, the machine instructions, when executed by a processor, further cause the processor to determine an equivalent circuit for the electronic package, using the admittance matrix.

19. The system of claim 18, wherein the machine instructions, when executed by a processor, further cause the processor to analyze the equivalent circuit with a circuit analysis program.

20. The system of claim 17, wherein the machine instructions, when executed by a processor, further cause the processor to input the scattering matrix into a microwave network model for analysis.

21. A method for modeling an electronic package that comprises a plurality of vias and at least two parallel layers defining spaced-apart parallel planes, for use in simulating characteristics of the electronic package to evaluate a design of the electronic package, comprising the steps of:

(a) modeling the electronic package, producing a model represented by an interior problem and an exterior problem;

(b) determining parameters relating to the vias and the parallel planes corresponding to the at least two parallel layers for use in solving said interior problem and said exterior problem;

(c) solving the interior problem to determine an admittance matrix of the electronic package, based on the parameters that were determined; and

(e) solving the exterior problem using the admittance matrix and the parameters that were determined to determine a scattering matrix, said scattering matrix being useful for evaluating the design of the electronic package.

22. The method of claim 21, further comprising the step of determining an equivalent circuit for the electronic package using the admittance matrix.

23. The method of claim 22, further comprising the step of using at least one of the equivalent circuit and the scattering matrix to determine at least one of a signal reflection, a signal transmission, and a signal coupling among vias in the electronic package.

24. The method of claim 23, wherein the step of using at least one of the equivalent circuit and the scattering matrix comprises the step of integrating the scattering matrix into a microwave network model.

25. The method of claim 23, further comprising the step of analyzing the equivalent circuit with a circuit analysis program.

26. The method of claim 21, wherein the step of solving the interior problem comprises the steps of determining an exciting wave using dyadic Green'"'"'s function, and using Foldy-Lax equations to determine the admittance matrix.

27. The method of claim 26, wherein the step of determining the admittance matrix using the Foldy-Lax equations comprises the steps:

(a) assuming each via is a cylindrical perfect electric conductor;

(b) decoupling transverse electric waves and transverse magnetic waves at the vias; and

(c) separately solving the Foldy-Lax equations for each of a plurality of waveguide modes, relative to the at least two parallel planes.

28. The method of claim 21, wherein the step of solving the exterior problem comprises the steps of integrating the admittance matrix into the exterior problem by relating a port voltage and a current for the vias, and then determining the scattering matrix using method of moment and matrix pencil method algorithms.

29. A method for modeling an electronic package that comprises a plurality of vias and at least two parallel layers defining spaced-apart parallel planes, for simulating characteristics of electronic packages to evaluate a design of the electronic package, comprising the steps of:

(a) representing voltages at active via ports as magnetic ring current sources;

(b) decomposing signal coupling among vias into an exterior problem with magnetic surface currents and an interior problem with magnetic surface currents;

(c) determining parameters relating to the vias and the parallel planes corresponding to the at least two parallel layers, for use in solving said interior problem and said exterior problem;

(d) solving the interior problem to determine an admittance matrix for the electronic package, based on the parameters that were determined;

(e) solving the exterior problem using the parameters that were determined and the admittance matrix, to determine a scattering matrix; and

(f) relating the admittance matrix and the scattering matrix by imposing a condition of equal and opposite magnetic surface currents.

30. The method of claim 29, further comprising the step of determining an equivalent circuit for the electronic package using the admittance matrix.

31. The method of claim 29, wherein the step of solving the interior problem comprises the steps of:

(a) applying dyadic Green'"'"'s function, expressed in terms of vector cylindrical waves and waveguide modes, to determine exciting waves for the electronic package;

(b) using Foldy-Lax equations to relate the exciting waves, incident waves, and scattering waves, thus decoupling each waveguide mode for the parallel layers, and obtaining the admittance matrix of an interior geometry of the electronic package.

32. The method of claim 31, wherein the step of using the Foldy-Lax equations assumes that radii the vias are sufficiently small to substantially reduce a number of harmonics used in the Foldy-Lax equations.

33. The method of claim 31, wherein the step of using the Foldy-Lax equations assumes that a separation between the parallel layers is sufficiently small to substantially reduce a number of propagating modes.

34. The method of claim 30, wherein the step of determining the equivalent circuit comprises the step of obtaining the surface magnetic currents on the surfaces around the vias by integrating the magnetic field over a cylinder representing each of the vias.

35. The method of claim 29, wherein the step of solving the exterior problem comprises the steps of:

(a) integrating the admittance matrix with the exterior problem by relating a port voltage and a current at the vias; and

(b) utilizing method of moments and the matrix pencil method algorithms to determine the scattering matrix.

36. The method of claim 29, further comprising the step of integrating the admittance matrix and the scattering matrix into a system simulation by utilizing a microwave network model.

37. The method of claim 30, further comprising the step of analyzing the equivalent circuit from the admittance and scattering matrices with a circuit analysis program.