LABUSSIERE, Cécile (25 Port St Sauveur, Toulouse, F-31000, FR)
SICARD, Etienne (4 Rue des Tamaris, Toulouse, F-31400, FR)
INSTITUT NATIONAL DES SCIENCES APPLIQUEES (135 Avenue De Rangueil, Toulouse Cedex, F-31077, FR)
LOCHOT, Christophe (Rue du Languedoc, Leguevin, F-31490, FR)
LABUSSIERE, Cécile (25 Port St Sauveur, Toulouse, F-31000, FR)
SICARD, Etienne (4 Rue des Tamaris, Toulouse, F-31400, FR)
| Claims (PCT)
1. A system (400) for measuring an electromagnetic field of an integrated circuit, the system (400) comprising a scan table for receiving the integrated circuit and a single three-dimensional probe (200) operably coupled to the scan table (425) and arranged to move over a surface of the integrated circuit to measure an electromagnetic field in at least two dimensions in a single movement of the three-dimensional probe (200).
2. The system (400) of Claim 1 wherein the single three-dimensional probe (200) measures a total electromagnetic field produced by the integrated circuit in a single movement of the three-dimensional probe (200) .
3. The system (400) of Claim 1 or Claim 2 further characterised in that the single three-dimensional probe (200) is formed from a single loop.
4. The system (400) of any preceding Claim further characterised in that the single three-dimensional probe (200) is configured as an isotropic probe.
5. The system (400) of any preceding Claim further characterised in that the single three-dimensional probe (200) comprises three orthogonal loops within a single electrical conductor.
6. The system (400) of any preceding Claim further characterised in that the single three-dimensional probe (200) is in a form of coaxial cable.
7. The system (400) of Claim 6 further characterised in that a central conductor of a coaxial cable is used as a single three-dimensional probe (200) .
8. The system (400) of Claim 7 further characterised in that the central conductor of the coaxial cable is looped back to an outer connector, such as a ground or shield.
9. The system (400) of any of preceding Claims 1 to 5 further characterised in that the single three- dimensional probe (200) is in a form of a printed circuit board.
10. The system (400) of Claim 9 further characterised in that the printed circuit board comprises a plurality of stripline metal tracks to implement y x' and y y' planes of the single three-dimensional probe (200) .
11. The system (400) of Claim 9 or Claim 10 further characterised in that the printed circuit board comprises a plurality of vias orthogonal to the printed circuit board to implement a ' z ' plane of the single three- dimensional probe (200).
12. The system (400) of Claim 10 or Claim 11 further characterised in that the printed circuit board comprises a radio frequency amplifier operably coupled to the stripline tracks and arranged to amplify electromagnetic field measurements of the single three-dimensional probe (200) .
13. The system (400) of any of the preceding Claims further characterised in that the single three- dimensional probe (200) is designed in a cubic form.
14. The system (400) of Claim 13 further characterised in that the cubic form is approximately lmm 3 .
15. The system (400) of any of the preceding Claims further characterised in that the system is arranged to perform a near-field characterization of electromagnetic radiation of an integrated circuit.
16. The system (400) of any of the preceding Claims further characterised in that the system is arranged to perform a near-field characterization of shielding material .
17. A probe (200) for measuring an electromagnetic field of an integrated circuit and arranged to move over a surface of the integrated circuit to measure an electromagnetic field, the probe (200) characterised in that it is of a three dimensional form capable of measuring an electromagnetic field in at least two dimensions of the integrated circuit within a single movement of the probe (200) .
18. The probe (200) of Claim 17 wherein the single three-dimensional probe (200) is configured to measure a total electromagnetic field produced by the integrated circuit in a single movement of the three-dimensional probe (200) .
19. The probe (200) of Claim 17 or Claim 18 further characterised in that the single three-dimensional probe (200) is formed from a single loop.
20. The probe (200) of any of preceding Claims 17 to
19 further characterised in that the single three- dimensional probe (200) is configured as an isotropic probe .
21. The probe (200) of any of preceding Claims 17 to
20 further characterised in that the single three- dimensional probe (200) comprises three orthogonal loops within a single electrical conductor.
22. The probe (200) of any of preceding Claims 17 to
21 further characterised in that the single three- dimensional probe (200) is in a form of coaxial cable.
23. The probe (200) of Claim 22 further characterised in that a central conductor of a coaxial cable is used as a single three-dimensional probe (200).
24. The probe (200) of Claim 23 further characterised in that the central conductor of the coaxial cable is looped back to an outer connector, such as a ground or shield .
25. The probe (200) of any of preceding Claims 17 to 21 further characterised in that the single three- dimensional probe (200) is in a form of a printed circuit board.
26. The probe (200) of Claim 25 further characterised in that the printed circuit board comprises a plurality of stripline metal tracks to implement y x' and y y' planes of the single three-dimensional probe (200) .
27. The probe (200) of Claim 25 or Claim 26 further characterised in that the printed circuit board comprises a plurality of vias orthogonal to the printed circuit board to implement a ' z ' plane of the single three- dimensional probe (200).
28. The probe (200) of Claim 26 or Claim 27 further characterised in that the printed circuit board comprises a radio frequency amplifier operably coupled to the stripline tracks and arranged to amplify electromagnetic field measurements of the single three-dimensional probe (200) .
29. The probe (200) of any of preceding Claims 17 to 28 further characterised in that the single three- dimensional probe (200) is designed in a cubic form.
30. The probe (200) of Claim 29 further characterised in that the cubic form is approximately lmm 3 .
31. The probe (200) of any of preceding Claims 17 to 30 further characterised in that the probe (200) is adapted to perform a near-field characterization of electromagnetic radiation of an integrated circuit.
32. The probe (200) of any of preceding Claims 17 to 31 further characterised in that the probe (200) is adapted to perform a near-field characterization of shielding material.
33. A method for measuring an electromagnetic field of an integrated circuit placed in an electromagnetic (EM) test system, the method comprising: connecting a single three-dimensional probe (200) to the EM test system; moving the single three-dimensional probe (200) over a surface of the integrated circuit in a single movement; and measuring an electromagnetic field by the single three-dimensional probe (200) in at least two dimensions.
34. The method of Claim 33 wherein the step of measuring comprises measuring a total electromagnetic field produced by the integrated circuit. |
SYSTEM, PROBE AND METHOD FOR PERFORMING AN ELECTROMAGNETIC SCAN
Field of the Invention
The present invention relates to a system, probe and method for performing an electromagnetic compatibility scan. The invention is applicable to, but not limited to, a system, probe and method for performing an electromagnetic compatibility scan when testing integrated circuits
Background of the Invention
Electromagnetic compatibility (EMC) testing of integrated circuits (ICs) is becoming more critical, particularly in the automotive field where EMC effects are prevalent. A Technical Report (IEC 61967-3) produced by the International Electromagnetic compatibility (IEC) standards committee describes one way to characterize and investigate the electromagnetic emission of an IC. In effect, IEC 69167-3 describes a surface scan method for identifying radiated emission from an IC. The IEC 69167- 3 standard also presents examples of probes, in particular a combined electric and magnetic field probe that allows simultaneous measurement of a component of the electric field and a component of the magnetic field.
L. Puranen et al . , in a document titled 'Simultaneous measurements of RF electric and magnetic near fields theoretical considerations', published in Dec. 1993 in IEEE transactions on 'Instrumentation and measurement', describes an electromagnetic (EM) probe consisting of six dipoles and six loops placed on all six sides of a small
cube. This EM probe sensor is not used for surface scan purpose, and is limited to a frequency of operation of 300 MHz. In effect, this probe actually uses two different probes, one for both the ' x r & J γ' direction (called Pxy) and one for the ' z ' direction (called Pz), as described with reference to FIG. 1. Six dipoles are used to minimize measurement error in a highly nonuniform electric field (see page 1002). In effect, this document describes a complex 3-D sensor that comprises six loops with six output signals, where each loop requires separate measurements.
Referring now to FIG. 1, a known method 100 for performing electromagnetic emission testing of an IC is illustrated. After a calibration phase 105, the first probe (Pxy) is positioned at a given altitude ( ' z ' direction) of the device under test (DUT), as shown in step 110. At this altitude ' z ' , the method then selects the ' x ' and J γ' co-ordinates (Pxy), as shown in step 115, to commence the EMC scan.
The known method 100 then sets the orientation of the scan for Pxy in the ' x r direction to ' 0 ' degrees to measure the Hx field, as shown in step 120, thereby commencing the scan at position (0,0) as shown in step 125. The electromagnetic field 'Hx' measurement is then made and recorded with the corresponding (y) coordinate, as shown in step 130. Once the measurement has been made, the EMC scan moves to the next location (in an ' x' direction) as shown in step 135. A determination is then made as to whether the EMC scan is at the end of the J x' direction measurement, as shown in step 140. If the EMC scan is not at the end of the ' x' direction measurement, in step 140, the process loops back to step 130 and
measures the electromagnetic 'Hx' field and records the corresponding (y) coordinates for this x co-ordinate.
If the EMC scan is at the end of the J x' direction measurement, in step 140, a determination is then made as to whether further J γ' direction measurements are required, as shown in step 145. If further y y' direction measurements are required, in step 145, the known method then sets the orientation of the scan to the next y coordinate in the y y' direction for Pxy to y 90' degrees to measure the Hy field for same (x,y) locations, as shown in step 150. Thus, the Hx and Hy scanning operation consists of two successive scans, for each location .
If further y y' direction measurements are not required, in step 145, the known method then positions a second probe Pz at the same altitude ( ' z ' direction), as shown in step 155. Thus, the same scanning operation commences again, at this new ' z ' position, with (x,y) co-ordinates of (0,0), as shown in step 160. The scanning operation then measures the electromagnetic field 'Hz' around the ' z ' axis for the same data points at each (x,y) location, as shown in step 165 and then moves to the next y x' and y y' location, as in step 170.
A determination is then made as to whether the measurement at this ' z ' is the last in the y x' and y y' direction, as shown in step 175. If the measurement at this ' z ' is not the last in the y x' and y y' direction, in step 175, the process loops back to step 165. However, if the measurement at this ' z ' is the last in the y x' and ' Y ' direction, in step 175, the scanning operation is complete, as shown in step 180.
Consequently, it is necessary to perform all three scans independently, and using at least two separate probes (with the first probe being rotated by 90 degrees to perform the second Cy' axis scan)) in order to provide the desired Hx(x,y), Hy(x,y) and Hz(x,y) EM field measurements. The resulting total field H is then computed using the rms formula:
H(x, y) = sqrt [Hx2 (x,y) + Hy2(x,y) + Hz2(x,y)] [1]
However, in implementing the aforementioned method of surface scanning an IC, the surface scanning system only uses a one-dimensional loop that measures a single (H) component of the magnetic field. US 20030001596A1, titled 'Method and apparatus for determining a magnetic field', describes such a measuring method for scanning the magnetic field radiated by an IC using a 1-D loop as a magnetic probe.
US20040183529A1, titled 'Electromagnetic wave measuring apparatus and method' describes a methodology for measuring electromagnetic radiation from electronic components simultaneously using several one-dimensional loops. The measurement of a magnetic field using a one dimensional loop requires three scan phases - one for each direction. Furthermore, performing an EM scan is very time consuming, for example performing an EM scan at one frequency on a 2*2mm 2 IC surface is known to require many hours in order to measure one component of the magnetic field.
In such prior art systems, the performance of the scanning probe is directly related to the accuracy of the
orientation of the probe, which, in turn, is prone to the ability of the scan Operator to accurately position and set the orientation of the probe before each scan phase. Thus, a need exists for an improved system, probe and method for performing an electromagnetic compatibility scan for an integrated circuit.
Summary of the Invention
In accordance with aspects of the present invention, there is provided a system, probe and method for performing an electromagnetic compatibility scan, as defined in the appended Claims.
Brief Description of the Drawings
FIG. 1 illustrates a known method for performing an electromagnetic compatibility scan.
Exemplary embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
FIG. 2 illustrates a 3-dimensional probe used in embodiments of the present invention;
FIG. 3 illustrates a 3-Dimensional probe in accordance with one embodiment of the present invention;
FIG. 4 illustrates a test set up for performing an EM scan of an integrated circuit, adapted in accordance with one embodiment of the present invention; and
FIG. 5 illustrates a method for performing an electromagnetic compatibility scan in accordance with one embodiment of the present invention.
Description of Embodiments of the Invention
In one embodiment of the present invention, a system for measuring an electromagnetic field of an integrated circuit comprises a scan table for receiving the integrated circuit and a single three-dimensional probe operably coupled to the scan table and arranged to move over a surface of the integrated circuit in a single movement. The single three-dimensional probe measures an electromagnetic field in at least two dimensions of the integrated circuit .
In this manner, by providing a single three-dimensional probe that is able to measure an electromagnetic field in at least two dimensions of the integrated circuit, a significant (by a factor of three) reduction in the time taken to perform an EM scan test on an IC, to obtain a total magnetic field characterization can be achieved. This is compared with a known one-dimensional loop that requires three surface scans in order to measure a total magnetic field.
In one embodiment of the present invention, the single three-dimensional probe may measure a total electromagnetic field produced by the integrated circuit in a single movement of the three-dimensional probe.
In one embodiment of the present invention, the single three-dimensional probe may be formed from a single electrical conductor loop and may comprise three
orthogonal loops within the single electrical conductor. In one embodiment of the present invention, the single three-dimensional probe may be configured as an isotropic probe. In this manner, the three-dimensional probe may be advantageously insensitive to orientation of the probe, due to the inherent isotropic nature.
In one embodiment of the present invention, the single three-dimensional probe may be in a form of coaxial cable, where a central conductor of the coaxial cable may be used as a single three-dimensional probe and may be looped back to an outer connector of the coaxial cable, such as a ground or shield. In this manner, the provision of a single three-dimensional probe may be implemented in an inexpensive form.
In one embodiment of the present invention, the single three-dimensional probe may be in a form of a printed circuit board (PCB) , where the PCB may comprise a plurality of stripline metal tracks to implement y x' and ' Y ' planes of the single three-dimensional probe. A PCB implementation may comprise a plurality of vias, orthogonal to the PCB to implement a ' z ' plane of the single three-dimensional probe. In one embodiment of the present invention, the PCB may comprise a radio frequency amplifier arranged to amplify electromagnetic field measurements of the single three-dimensional probe.
In this manner, the provision of an additional RF low noise amplifier may be added on the PCB in order to increase the performance of the probe.
In one embodiment of the present invention, the single three-dimensional probe may be designed in a substantially cubic form.
In one embodiment of the present invention, the system may be arranged to perform a near-field characterization of electromagnetic radiation of an integrated circuit, and/or may be arranged to perform a near-field characterization of a shielding material.
In one embodiment of the present invention, a probe for measuring an electromagnetic field of an integrated circuit and arranged to move over a surface of the integrated circuit to measure an electromagnetic field is described. The probe is of a three dimensional form and is capable of measuring an electromagnetic field in at least two dimensions of the integrated circuit within a single movement of the probe.
In one embodiment of the present invention, a method for measuring an electromagnetic field of an integrated circuit placed in an electromagnetic (EM) test system is described. The method comprises connecting a single three-dimensional probe to the EM test system; moving the single three-dimensional probe over a surface of the integrated circuit in a single movement; and measuring an electromagnetic field by the single three-dimensional probe in at least two dimensions.
The inventive concept proposes an electromagnetic probe that is based on three perpendicular square loops. In this manner, the inventive concept advantageously enables an EM scanning operation to calculate a total magnitude
of the magnetic field produced by the IC, to be performed in a single step.
Referring now to FIG. 2, a plan view of a 3-dimensional probe 200, used in embodiments of the present invention, is illustrated. Notably, the 3-dimensional probe 200 comprises an electrical conductor lying in each of the desired x, y and z axis 205, 210, 215. These electrical conductors, in a unique form factor, are used to respectively measure the electromagnetic field Hx, Hz, Hy in a single surface scanning operation across an IC.
Thus, in moving the probe 200 over the IC surface in a scanning operation, the electrical conductors of the probe 200 provide an equivalent Hx loop 250 measurement in an y x' direction, an equivalent Hy loop 245 measurement in a J γ' direction and an equivalent Hz loop 240 measurement in a ' z ' direction, as shown.
In one embodiment of the present invention, a coaxial realization of the 3-Dimensional probe may be implemented. In this embodiment, electrical conducting the loops may be built using the central conductor of the coaxial cable, configured with 90 degree angle bends in a cube form factor, as illustrated in FIG. 3. In one embodiment of the present invention, the cube may comprise a side length of approximately lmm, for example using high density interconnect (HDI) substrate technology. The connector may then be looped back to the outer connector (GND or shield) of the coaxial cable within the probe body.
Thus, in one embodiment of the present invention, the form factor of the 3-Dimensional probe 200 is as
illustrated in FIG. 3. Here, the 3-Dimensional probe 200 is readily seen as comprising an electrical conductor lying in each of the desired axis 205, 210, 215. These electrical conductors have a unique form factor that comprises vertical and lateral separation between electrical conductors lying in a particular direction/orientation. These electrical conductors are thus used to respectively measure the electromagnetic field Hx, Hz, Hy in a single surface scanning operation across an IC.
In one embodiment of the present invention, the probe 200 may be implemented using printed circuit board (PCB) technology. In this embodiment, the edges of the cube may be manufactured using a series of striplines (for the y x' and 'y' directions) and a series of vias (for the ' z ' direction) when the ' z ' direction is orthogonal to the board. A skilled artisan will appreciate that this realization requires at least two layers to complete a three dimensional loop, with the vias connecting the striplines of respective layers. Advantageously, a PCB realization provides a much smaller geometry for the probe 200, allowing it to be readily used for IC electromagnetic scanning.
Referring now to FIG. 4, a test set up 400 that has been adapted to perform an EM scan of an integrated circuit is illustrated in accordance with one embodiment of the present invention. The test set up 400 comprises a workstation or personal computer (PC) 410 that is operably coupled to a mechanical test jig 420 via a software controller 410. An integrated circuit (namely the device under test) is placed on a scan table 425. A moving part 430 of the test jig 400 is capable of moving
the 3-Dimensional probe 200 in the altitude ' z ' direction. In this manner, the 3-Dimensional probe 200 is able to be accurately set by the controller 410 in the altitude ' z ' direction. In addition, a manual micrometric positioning system 450 is available to adjust a position of the 3-Dimensional probe 200.
The EM (H) field measurements from the 3-Dimensional probe 200 are provided to a spectrum analyzer 465 via a 3OdB low noise pre-amplifier 460, and thereafter to the workstation or PC 410. Set up parameters may be applied by the workstation or PC 410, or provided to 405 the workstation or PC 410. The resulting EM measurements may be extracted in files 470 from the workstation or PC 410. The measurements capture the received power in the resolution bandwidth (RBW) of the spectrum analyser (in dBm) . For each (x,y) point, a spectrum is measured for a range of frequency bands .
Referring now to FIG. 5, a method 500 for performing an electromagnetic compatibility scanning operation is illustrated in accordance with one embodiment of the present invention. The method starts in step 505, with a probe position (referred to as a 'Pcube') selected for an altitude ' z ' position, as shown in step 510. An orientation of the scan is set, so that the 3-Dimensional probe is located at the scan starting position (0,0) in step 515, and thereafter able to simultaneously measure the Hx, Hy and Hz fields, as shown in step 520. The electromagnetic fields 'Hx', y Hy ' and 'Hz' are measured and recorded with the corresponding (x,y,z) coordinates of the probe. Once the measurement has been performed, the EMC scan moves to the next location, as shown in step 525. If the scanning operation is not complete, in step
530, the process loops to step 520 and the electromagnetic fields 'Hx', y Hy ' and 'Hz' are again measured at the new location. Otherwise, the scanning operation is complete, in step 535.
It is envisaged that the aforementioned arrangement and method for EM scanning may be applied in testing any type of integrated circuit, such as microcontrollers that are known to be generate EM interference.
It will be understood that the improved system, probe and method for performing an electromagnetic compatibility scan, as described above, aims to provide at least one or more of the following advantages: (i) Employing the inventive concept enables a significant (by a factor of three) reduction in the time taken to perform an EM scan test on an IC, to obtain a total magnetic field characterization, compared with a typical one-dimensional loop that requires 3 surface scans in order to measure a total magnetic field;
(ii) Employing the inventive concept enables a significant reduction in cost in performing an EM scan test on an IC and obtaining a total magnetic field characterization, compared with a use of, say, three separate probes to measure a total magnetic field in the same period of time.
(iii) In a PCB implementation of the 3-Dimensional probe, an additional RF low noise amplifier may be readily added on the PCB in order to increase the performance of this probe;
(iv) The inventive concept supports applications where multiple probes are required, whilst providing improved positioning certainty;
(v) The inventive concept may be easily integrated in a matrix of probes, to allow an instantaneous electromagnetic scan to be performed using a PCB realization that provides a smaller probe geometry; and
(vi) The 3-Dimensional probe is advantageously insensitive to orientation, due to its inherent isotropic nature .
It will be appreciated that any suitable distribution of functionality between different functional units may be used without detracting from the inventive concept herein described. Hence, references to specific functional devices or elements are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization. In this regard, for example in a PCB form of 3-dimensional probe embodiment, it is envisaged that the PCB may also contain a processor to process the EM signals measured by the probe.
In particular, it is envisaged that the aforementioned inventive concept can be applied by a semiconductor manufacturer to any probe design, for example a probe in integrated circuit form, that is capable of simultaneously measuring EM field data in y x', y y' and ' z ' directions .
Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with
particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term 'comprising' does not exclude the presence of other elements or steps.
Furthermore, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather indicates that the feature is equally applicable to other claim categories, as appropriate.
Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second" etc. do not preclude a plurality.
Thus, a system, probe and method for performing an electromagnetic compatibility scan have been described, wherein the aforementioned disadvantages with prior art arrangements have been substantially alleviated.