| The backplane is the basis of electronic equipment system. The trend of backplane is “high density, high frequency and high speed”. Ultra-multilayer Blind-hole Press-fitting backplane is mostly interested due to smaller signal transmission loss, higher reliability and combination with more daughter boards. The conductive paste interconnection technology for Blind-hole Press-fitting backplane applications is researched in this dissertation, a new structure of the conductive paste interconnection for Blind-hole Press-fitting backplane applications was designed. The limitation of traditional Z- axis interconnect structure for printed circuit board was broken through by this new interconnection technology. Plug hole interconnection technology solves the pollution problem of blind hole during the through-hole plating process, meet with the requirements of backplane pressure fit mount technology, and simplifies the multilayer circuit board production process. In this dissertation, the manufacturing technology of new structure of the conductive paste interconnection was studied, the reliability of plug hole interconnection structure for Blind-hole Press-fitting backplane applications was investigated, and the signal integrity of plug hole interconnection structure was observed.In order to obtain good electrical and physical performance of conductive paste and avoid the simultaneous curing behavior of prepreg, the resistance and bond strength experiments of the conductive paste were designed to investigate the resistance performance of conductive paste after diffident preprocessing. Experimental results show that the best pre-curing conditions of conductive paste are pre-curing temperature of 60 oC and pre-curing time for 30 min. The influence of prepreg and the different structure of conductive–through holes on conductive paste interconnection technology were also studied in this dissertation. In lamination parameters are optimized by the orthogonal experiment. the optimum lamination parameters is switch pressure point at 80 oC, heating rate 3.0 oC /min, the maximum pressure is 2.76 MPa. The defects of shorts glue malposition are improved by cushion, directly lamination way can. Besides, the flexible pin positioning. Prepreg with good stability and bigger fluidity can improve the problem of thick board lamination such as malposition, lack of glue and hollows.The reliability of conductive paste interconnection technology for Blind-hole Press-fitting backplane applications is investigated through the high and low temperature impact experiment and reflow soldering test. The data show that the pre-curing of conductive paste is helpful to improve the reliability of plugging hole interconnection structure. conductive paste which can’t form intermetallic compound with bonding pad improve the resistance results of high and low temperature impact test, applicable to backplane pressure fit mount technology. conductive paste which filler contain Sn ans Ni can form intermetallic compound with bonding pad improve the resistance results of reflow soldering test, suitable for welding components of multilayer printed circuit board. According to the experimental data in this paper, the rate of resistance change of holes chain on the Blind-hole Press-fitting backplanes which was manufacture by the conductive paste interconnection technology less than 10% after 500 cycles high and low temperature impact test, and satisfied with the reliability requirements of the backplane production.HFSS electromagnetic simulation software is used to analysis the circuit design of signal integrity of different conductive paste interconnection structure, the best plug hole interconnection structure for signal integrity of the circuit design is found as linear interconnection structure. The signal integrity of conductive paste interconnection Blind-hole Press-fitting backplane is investigated by vector network analysis(VNA) instrument. According to the measurement result, the insertion loss of copper through hole interconnection structure is superior to the conductive paste interconnection’s when the frequencies range from the 0 to 20 GHz. However, the value of insertion loss and return loss of two structures are close. The reliability and electrical performance of conductive paste interconnection technology can meet with the requirements of Blind-hole Press-fitting backplane. New conductive paste interconnection technology can replace the traditional copper interconnection structure, as a Z-axis interconnection technical solution of Ultra-multilayer Blind-hole Press-fitting backplane. |
PDF Full Text Request