Simulation of printed circuit board impedance variations and crosstalk effects

• US 9,244,120 B2
• Filed: 06/15/2012
• Issued: 01/26/2016
• Est. Priority Date: 03/26/2010
• Status: Active Grant

• Current Assignee: Lenovo International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Enterprise Solutions (Singapore) Pte., Ltd. (Lenovo Group Ltd.)
• Inventors: Herrman, Bradley D., Mutnury, Bhyrav M., Rodrigues, Terence
• Primary Examiner(s): Nguyen, Vinh
• Application Number:
  US13/524,213
• Publication Number:
  US 20120249162A1
• Time in Patent Office: 1,320 Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/2896 Testing of IC packages; Test features related to IC packages containers per se H01L23/02, encapsulations per se H01L23/28

Abstract

A method for altering an impedance of a conductive pathway on a microelectronic package includes applying a magnetic field to the conductive pathway. The microelectronic package may be, for example, a printed circuit board. The method also includes controlling a magnitude of the magnetic field at the conductive pathway for altering the impedance of the conductive pathway. The magnetic field may be applied by, for example, an electromagnet or a permanent magnet. A magnetic field may also be applied for simulating crosstalk effects on a conductive pathway.

Claims

1. A method comprising:

applying a magnetic field to a conductive pathway on a microelectronic package;

controlling a magnitude of the magnetic field at the conductive pathway for altering an impedance of the conductive pathway to be within a predetermined impedance range; and

testing the microelectronic package while the impedance of the conductive pathway is altered to simulate impedance variations of the conductive pathway within the predetermined impedance range.

2. The method of claim 1, wherein the microelectronic package is a printed circuit board.

3. The method of claim 1, wherein applying a magnetic field comprises using an electromagnet to apply the magnetic field to the conductive pathway.

4. The method of claim 3, wherein controlling a magnitude of the magnetic field comprises moving the electromagnet with respect to the conductive pathway.

5. The method of claim 3, wherein controlling a magnitude of the magnetic field comprises controlling electric current passing through the electromagnet.

6. The method of claim 1, wherein applying a magnetic field comprises using a permanent magnet to apply the magnetic field to the conductive pathway.

7. The method of claim 6, wherein controlling a magnitude of the magnetic field comprises moving the permanent magnet with respect to the conductive pathway.

8. The method of claim 1, wherein controlling a magnitude of the magnetic field comprises controlling the magnitude of the magnetic field to one of increase and decrease the impedance of the conductive pathway to be within a predetermined impedance range.

9. A method comprising:

applying a magnetic field to a conductive pathway on a microelectronic package;

controlling a magnitude of the magnetic field at the conductive pathway for altering a crosstalk effect on the conductive pathway to be within a predetermined crosstalk effect range; and

testing the microelectronic package while the crosstalk effect is altered to simulate crosstalk effect variations of the conductive pathway within the predetermined crosstalk effect range.

10. The method of claim 9, wherein the microelectronic package is a printed circuit board.

11. The method of claim 9, wherein applying a magnetic field comprises using an electromagnet to apply the magnetic field to the conductive pathway.

12. The method of claim 9, wherein applying a magnetic field comprises using a permanent magnet to apply the magnetic field to the conductive pathway.

13. A system comprising:

a microelectronic package including a conductive pathway;

test equipment coupled to the microelectronic package for testing the microelectronic package;

a magnetic field generator positioned in proximity to the conductive pathway and configured to generate a magnetic field for application to the conductive pathway such that the magnetic field simulates at least one of an impedance value and crosstalk effect of the conductive pathway during testing of the microelectronic package; and

a computing device configured to;

determine a predetermined range of one of impedance values and crosstalk effect values for testing the microelectronic package based on a calibration of the magnetic field generator; and

control the magnitude of the magnetic field generated by the magnetic field generator to simulate the one of impedance values and crosstalk values within the predetermined range during testing of the microelectronic package.

14. The system of claim 13, wherein the microelectronic package is a printed circuit board.

15. The system of claim 13, wherein the magnetic field generator is a permanent magnet.

16. The system of claim 13, wherein the magnetic field generator includes an electromagnet.

17. The system of claim 16, wherein the computing device is further configured to control electric current passing through the electromagnet.

18. The system of claim 16, wherein the magnetic field generator includes another electromagnet coupled to the computing device for control of the other electromagnet by the computing device.

19. The system of claim 13, wherein the calibration of the magnetic field generator comprises the computing device measuring the impedance of the conductive pathway while the magnetic field generator applies the magnetic field to the conductive pathway.

20. The system of claim 19, wherein the magnetic field generator includes an electromagnet, and

wherein the computing device is coupled to the electromagnet and configured to control a magnitude of electric current passing through the electromagnet for controlling the magnitude of the magnetic field applied at the conductive pathway.

21. The system of claim 19, further comprising an electronic meter coupled to the microelectronic package and configured to measure an impedance of the conductive pathway while the magnetic field is being applied to the conductive pathway for determining the measured impedance.