Research On The Process And Reliability Of RFID Tag Packaged By ACA

RFID (radio frequency identification) is considered as the most popular attentive and advanced contactless sensor recognition technology and widely used in wireless business, identification, manufacturing, transportation, logistics and other areas. Though RFID will eventually replace barcode, one of the bottlenecks which prevent its wider and larger-scale use is the high price of RFID tag. With chip and antenna manufacturing costs dropping continuously, the relative share of packaging cost gradually increases, Therefore the Flip Chip technology of using ACA (anisotropic conductive adhesive) to package and manufacture the low-cost RFID tag has been widely concerned and applied in industry.This paper focused on the research on the process and reliability of RFID tag packaged by ACA. The Heat-Pressing time was set for 10s, the Au-sprayed RF chip was adopted especially to make the test samples to determine the appropriate pressure for 1.4MPa, then three kind of ACA were tested to package the RFID tag under various heat-pressing temperature to study on the temperature on the effect of electrical, mechanical and RF response properties of RFID tag during environment reliability test (HTH, 85 oC, 85% RH, 168h and HTS, 85 oC, 168h). Also the winding test, static tension test and pure bend test were designed to evaluate the reliability of flexible tag bearing break and bend stress. The test results indicated that: For ACA-1 with Ni-coating polymer sphere particles, when the temperature was below 160 oC, the ACA was not cured and low bond strength and high contact resistance were obtained. When the temperature was above 170 oC, the contact resistance was increased more and bond strength decreased after HTH test. So 160 oC is comparatively more suitable Heat-Pressing temperature. Under a suitable Hot-Pressing temperature of 120 oC, the average contact resistance of tag packaged by ACA-2 which contained Ni particles was about 4?, but after HTH tests it was increased 1～4 times and after winding test it increased only about 50%, so ACA-2 was fit for flexible temperature-sensitive PET antenna substrate. The destructive power of winding test was mainly from pure bend and destructive power from static tension was not found. HTH test had no impact on RF performance. For ACA-3 in which the better conductive Ag particles replaced Ni particles, under a suitable Hot-Pressing temperature of 170 oC, before and after HTH test the contact resistance was very small and the change was very small in comparison with ACA-2, but RF response performance was passed only at 60% after HTH test and it was because of the difference of the adhesive.