SIMULATION OF PRINTED CIRCUIT BOARD IMPEDANCE VARIATIONS AND CROSSTALK EFFECTS

• US 20110234238A1
• Filed: 03/26/2010
• Published: 09/29/2011
• Est. Priority Date: 03/26/2010
• Status: Active Grant

• Current Assignee: Lenovo International Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Mutnury, Bhyrav M., Rodrigues, Terence, Herrman, Bradley D.
• Granted Patent: US 8,289,043 B2
• Time in Patent Office: Days
• US Class Current: 324/551
• 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; and

controlling a magnitude of the magnetic field at the conductive pathway for altering an impedance of the conductive pathway.

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, and

wherein the method further comprises testing the microelectronic package while the impedance of the conductive pathway is altered.

9. A method comprising:

using a magnetic field generator to apply a magnetic field to a conductive pathway on a microelectronic package;

measuring an impedance of the conductive pathway while the magnetic field is being applied to the conductive pathway;

calibrating the magnetic field generator based on the measured impedance;

using the magnetic field generator to control the magnitude of the magnetic field to alter the 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.

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

11. The method of claim 9, wherein the magnetic field generator comprises:

an electromagnet; and

a computing device 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 at the conductive pathway.

12. A method comprising:

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

controlling a magnitude of the magnetic field at the conductive pathway for altering a crosstalk effect on the conductive pathway.

13. The method of claim 12, wherein the microelectronic package is a printed circuit board.

14. The method of claim 12, wherein applying a magnetic field comprises using an electromagnet to apply the magnetic field to the conductive pathway.

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

16. A system comprising:

a microelectronic package including a conductive pathway;

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

a magnetic field generator positioned in proximity to the conductive pathway and configured to apply a magnetic field to the conductive pathway such that the magnetic field alters an impedance and crosstalk of the conductive pathway for simulating impedance variations while the microelectronic package is under testing.

17. The system of claim 16, wherein the microelectronic package is a printed circuit board.

18. The system of claim 16, wherein the magnetic field generator is a permanent magnet.

19. The system of claim 16, wherein the magnetic field generator includes an electromagnet and a computing device.

20. The system of claim 19, wherein the computing device is configured to control electric current passing through the electromagnet.

21. The system of claim 19, wherein the computing device is configured to control the magnitude of the magnetic field such that the impedance of the conductive pathway is altered to an impedance within a predetermined impedance range, and

wherein the computing device is configured to control the electromagnet to maintain the impedance within the predetermined impedance range while the testing equipment tests the microelectronic package.

22. The system of claim 19, wherein the magnetic field generator includes another electromagnet coupled to the computing device for control of the other electromagnet by the computing device.

23. The system of claim 16, further comprising a computing device calibrated based on a measured impedance of the conductive pathway while the magnetic field generator applies the magnetic field to the conductive pathway, and

wherein the computing device is configured to control the magnitude of the magnetic field such that the impedance of the conductive pathway is altered to an impedance within a predetermined impedance range.

24. The system of claim 23, 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.

25. The system of claim 23, 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.