| RFID(Radio Frequency Identification)electronic tags have been used by a small number of textile and apparel companies to monitor the production and circulation of goods in real time because of their advantages of non-contact,long distance,more obstacles,readable and writable.However,the existing RFID tags are often based on hard film materials such as PET and polyimide,which do not meet the requirements of flexible applications and are not suitable for the whole life cycle of textile products.Therefore,textile-based screen-printed RFID tags have attracted great attention.The design and development of such fabric-based tags need to solve technical problems such as the flip-chip packaging bonding process and the reliability evaluation of the application environment.Some scholars have carried out related research on the flip-chip packaging bonding process of rigid film substrate tags such as PET and machine-washing of fabric-based tags and have made certain progress.It is also necessary to do the flip-chip packaging bonding process of fabricbased tags,further research need to conduct to determine the influence of these processes on the performance of textile-based tag antennas and to evaluate the adaptability of the prepared tags to the application environment.In view of the current problem of insufficient packaging bonding process of textile-based RFID tags and the evaluation of the adaptability of the application environment,this paper takes textilebased screen printing T-match dipole UHF RFID tags as the research object,optimizes the bonding process of the tag,and evaluates the washability of the printed tag,and explores the machine wash damage mechanism and improvement measures of the tag,which will lay the foundation for the establishment of quality evaluation methods and standards for such tags in the future.The specific research contents and conclusions are as follows:(1)Exploring the influence of flip-chip packaging bonding process parameters on the performance of textile-based tag antennas.It was found that as the bonding temperature and pressure increase,the resonant frequency shifting of the tag antenna tends to increase,but the bonding time and the resonant frequency of the antenna have no obvious law;when bonding at low temperature and pressure,the wire resistance of the tag's antenna conductor will increase;the bonding temperature,pressure,and time all have a significant effect on the reading distance of the tag,and the bonding pressure has the most significant effect on the reading distance of the tag.Higher bonding pressure will increase the reading distance of the tagAiming at the problem that the flip-chip packaging bonding process has an unclear influence on the performance of the fabric-based UHF RFID tag antenna,the control variable method was used and the antenna conductor resistance,S-parameter(S11)and the reading distance of the corresponding tag were used to characterize the effect of the bonding parameters on the performance of the tag antenna.At the same time,we used an optical microscope to observe the apparent morphology and cross-section of the tag antenna conductor before and after bonding,and the adhesion between the chip and the antenna.The final packaging process parameters were selected by combining the relative change in resistance of the tag antenna before and after bonding,the change in the S-parameter(S11),the reading distance of the tag,and the bond strength between the chip and the antenna.The experimental results show that the tag's bonding parameters need to consider the heat-resistant temperature of the substrate and the secondary curing of the antenna conductor.When the bonding temperature is 120 ° C,the bonding pressure is 1.1N,and the bonding time is 6s,the relative change rate of the resistance and the offset of the resonance frequency of the tag antenna are small,the reading distance of the tag is the longest,which can reach nearly 20 m,and the performance is stable.(2)Exploring the effect of machine washing on the reading performance of the tag and the destruction mechanism,it was found that the main cause of the reading failure of the tag after machine washing was the destruction of the conductive layer of the antenna by mechanical action,followed by the break of the chip bridge interface.By testing and comparing the change in the reading distance and the appearance of the flipchip packaging tag before and after machine washing,it was found that the antenna conductive layer has been damaged or even broken.In addition,in order to further observe the influence of machine washing on the stability of chip bridging,a PDMS protective layer was coated on the chip to compare the effect of machine washing damage before and after coating.The results show that whether or not PDMS is coated on the chip,the tag reading performance fails after one machine wash,and the chip does not loosen or fall off significantly after one machine wash.However,it was observed that the machine's main damage to the tag's antenna conductivity,which is the main reason for the poor machine washability of the tags.(3)Investigating the measures to improve the machine washability of the tag,and propose to apply a local coating process to protect the antenna conductive layer.The results showed that adding a coating to the conductive layer of the antenna and the surface of the chip can improve the machine washability of the tag,and the coating thickness could be significantly enhanced when the thickness of the conductive layer is equivalent to the thickness of the conductive layer.As found in the research content(2),the conductive layer of the antenna was easily damaged during machine washing.In this experiment,the surface of the conductive layer of the tag antenna was partially coated to test the changes in resistance and S-parameter(S11)of tag antennas with different protective coating thicknesses before and after bending and twisting.The experimental results showed that the relative change rate and resonance frequency shifting of the tag antenna after bending and twisting tend to decrease first,increase later,and finally tend to remain unchanged as the coating thickness increases.Further test was conducted to evaluate the change of the reading distance of the tags with different protective coating thickness before and after washing.It was found that the coated tag was printed only by screen printing,and the reading performance failed after 7 machine washings,mainly due to chip looseness and detachment,and chip-antenna connection fracture,followed by fracture of the conductive layer.Adding an extra coating to the chip-antenna connection,it was found that the resistance to machine washing of all coated tags has increased,especially for 1-layer coated tags.At this time,the thickness of the coating is the same as that of the conductive layer,and it can withstand 12 machine washings.But in the end,the chip reading failure is mainly caused by the loss of the tag.To sum up,the flip-chip packaging bonding process and machine washability of textile-based UHF RFID tags and the shortcomings of the existing research are explored by changing the flipchip bonding parameters and coating protection measures to improve the machine washability.The relationship between the textile-based UHF RFID tag flip-chip packaging bonding process and the relationship between the thickness of the protective coating and the tag reading performance was explored.These research conclusions complement the textile-based screen-printed UHF RFID tag flip-chip packaging bonding.The technology has laid the foundation for the application and promotion of tags.At the same time,the research conclusions are also useful for the flip-chip packaging bonding process of textile-based screen-printed flexible electronic devices,and also provide certain guidance for enhancing the machine washability of textile-based screen-printed flexible electronic devices. 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