Research On Interconnection Structures Transmission Characteristics In High Speed And High Density Circuits

With the development of large scale integrated circuit technology,there are more and more the pins on the chip.The increasing miniaturization of physical size on the printed circuit board(PCB)make interconnection lines spacing,the line width reach micron level and submillimeter level,therefore,research on transmission signal integrity(SI)of micron level interconnect of the printed circuit board with great urgency.The traditional research on signal integrity of interconnect is generally carried out from two aspects: one is to study the signal integrity of micronanometer-level interconnect inside the chip;The other is to study the signal integrity of millimeter-level interconnection lines on printed circuit boards.Among the reported research results,there are few researches on the signal integrity of micrometer and submillimeter levels interconnection lines on printed circuit boards.In this paper,the signal integrity of micrometer and submillimeter levels on the PCB are studied,and the anti-irradiation effect of internal micronanometer interconnect in IC is researched.The main work and innovations are as follows:1.Focusing on the crosstalk problem of high-speed and high-density interconnects within micron and submillimeter levels,the paper puts forward the countermeasure and consideration on the crosstalk mechanism research and the crosstalk parameters extraction,including the capacitive coupling parameters caused by the wire spacing and inductive coupling parameters caused by the length of interconnects between micron parallel interconnects;The equivalent RLGC circuit models have used the distribution parameters R?L?G?C method.The characteristic change is simulated and analyzed between S31-frequency and S41-frequency of the micron parallel interconnection,corresponding to structure change on either line width,line spacing,or line length.All studies show that the crosstalk characteristics of millimeter parallel interconnects on PCB are the periodic oscillation rising,not monotonic with the increase of frequency,and the crosstalk increases with the addition of line length,while the decrease of micron line spacing and width.During each crosstalk trough frequency window period,there is a trough resonance frequency hundreds MHz bandwidth frequency characteristic of the near end crosstalk S31 and the far end crosstalk S41.When the sampling interconnect line length L = 4cm,line width w = 100 ?m,and line spacing d = 100 ?m,with the range of 0-3GHz.Among the 0 GHz-1.8 GHz,the crosstalk signal increases monotonically;While the range of the 1.8GHz~2.25 GHz frequency,the crosstalk signal decreases monotonically at first,then increases monotonically,then dropes totally less than-20 d B;On the 2.25GHz~3.0GHz range,the crosstalk signal increases monotonically with the frequency.2.Based on the theory and simulation analysis,ten different specifications PCB of micron parallel structure interconnect are designed and manufactured.The interconnect line spacings are 100~400?m rounding respectively,and the interconnect line widths are 100~400?m rounding respectively,and the interconnect line lengths are 1~4cm rounding respectively.The aforementioned parallel interconnects signal is tested,and the measured results are in good agreement with the simulation,as show that the crosstalk characteristics increase nonmonotonously along with the range 0~15GHz.The crosstalk shows the periodic oscillation rising.When the sampling line length L = 4cm,line width w = 100 ?m,and line spacing d = 100 ?m,with the range of 0-3GHz.The crosstalk attenuation of S41 is more than-45 d B,more 500 MHz range at the center point of 2.0GHz.3.Via is a common interconnection structure,which the SI is studied of the via interconnection structure on the high-speed and high-density PCB,and the distribution parameter of circular waveguide extracted are studied the RLGC circuit model of via structure of via radius,via loaded branch line width and via loaded branch line length on S-parameter.The physical model is constructed,and the results show that the via structure in metal shielding layer has the characteristics of electromagnetic protection,and the via structure connecting multilayer in metal shielding cavity has the characteristics of filtering the electromagnetic waves.A band-pass filter of via structure has been made,which realizes the function of connecting and filtering the specific frequency signals in the upper and lower multilayer circuit boards.The pass-band filter center frequency is 2.095 GHz,and 470 MHz range.4.Considering aiming at the high-density circuit under the condition of high-speed signal transmission,the electromagnetic irradiation effect has been explored and researched of micro nanometer size,the nanometer line width and spacing,the micron line length in the chip.The equivalent RLGC distribution circuit have been designed of the micro-nano interconnect.The characteristics have been simulated and analyzed with respect to either line width,line spacing,or line length.The results show that irradiation has been affected on the effective transmission signal line length and the equivalent characteristic impedance of the interconnect.