Research On Key Technologies Of Near Field Scanning System Applied To Integrated Circuits

Electronic devices have become more miniaturized,high-frequency and high-density,with the rapid development of science and technology,resulting in more serious electromagnetic reliability problems.In circuit component modules,printed circuit boards and integrated circuits,near-field scanning technology has advantages in finding the source of electromagnetic interference and evaluating electromagnetic interference.That means near-field scanning has broad application prospects.The probes of current near-field scanning systems generally suffer from insufficient bandwidth,low sensitivity and poor spatial resolution.Moreover,most of the current probes detect the magnetic field parallel to the surface of the device,and there are fewer probes capable of measuring the magnetic field in the vertical direction.In response to this situation,this article proposes a probe that can measure the magnetic field in the vertical direction on the surface of the device under test,which is suitable for the near-field scanning system of high-bandwidth integrated circuits.The probe performance goal is 1-10 GHz broadband,spatial resolution of 1mm and above,and sensitivity above-40 d B S/m,the following is the work done in this article:1.Started from the signal transmission and combined with our probe design ideas,through electromagnetic modeling and simulation analysis on the wiring method,the abrupt change of wire width and the addition of grounded metal vias,the optimized design of the transmission structure of the magnetic field probe is obtained.2.Aiming at the probe's bandwidth,probe's sensitivity,probe's spatial resolution,and measuring the magnetic field in the vertical direction,a horizontal induction loop method and low temperature co-fired ceramic(LTCC)process are used.We designed and manufactured the single-ring magnetic field probe and the double-ring magnetic field probe.In the actual test,the test device composed of the probe,the microstrip line and the vector network analyzer was used to test the frequency response,spatial resolution and Sensitivity.Tests show that the single-ring probe has a spatial resolution of less than 1mm at 0.1GHz-1.5GHz and can reach up to 0.8mm,and its sensitivity can reach-35 d B S/m @ 1GHz and-39 d B S/m @ 1.5GHz.In terms of bandwidth,the gap is not small,but the spatial resolution exceeds our target.And the sensitivity is very close to our target.For dual-ring probes,the bandwidth is 1GHz-10 GHz,the spatial resolution is 1mm-1.2mm,and the sensitivity is higher than-40 d B S/m @ 1GHz,5GHz and 10 GHz.Bandwidth and sensitivity achieved the expected goals.3.Due to the international IEC61967 standard lacks a calibration method for the horizontal loop magnetic near-field(measurement of the vertical magnetic field)probe,we have studied the IEC61967 probe calibration method and analyzed the typical magnetic field in the space above the microstrip line.A calibration method of horizontal loop magnetic near-field probe based on microstrip line TEM field is presented and verified.4.By analyzing the characteristics of the magnetic field in the vertical direction,the line width of the measured microstrip line can be approximated from the measurement results of the probe,and the closer the distance between the probe and the microstrip line,the closer to the actual line width.The results show that by detecting the magnetic field in the vertical direction,the lack of magnetic field information in the horizontal direction can indeed be compensated,and the magnetic field information on the surface of the device under test can be improved.5.Finally,we simulated and verified the effect of the combination of the magnetic field probe and the integrated amplifier circuit.The results show that the magnetic field probe combined with the integrated amplifier circuit can greatly improve the transmission gain and sensitivity of the probe while ensuring good spatial resolution and little in-band fluctuations affected by the amplifier circuit.The transmission gain of the probe is increased by about 15 d B in the 1-15 GHz frequency band.