Study On Irradiation Resistance Of Plastic Package Chip Materials

With the progress of science and technology and the development of industry,substantive progress has been made continuously from the study of spaceborne chips.However,there are also great challenges because of the complicated and changeable space environment which includes space irradiation,extreme temperatures and so on.Space irradiation,in particular,is the major factor for performance changes of epoxy molding compound of the integrated circuit package.High energy rays in the space environment have a great impact on the performance of polymer materials.They are liable to cause structural and performance changes in organic polymers.Therefore,under radiations,the performance stability of epoxy molding compound that for plastic package of chips is of paramount importance.To ensure the stability of use and to avoid materials failure,radiation resistance should be carefully evaluated in advance.In this thesis,the influence of y rays irradiation to common epoxy resin bisphenol A glycidyl ether(DGEBA)and three kinds of tetrafunctional epoxy resin systems with DDS as curing agent(four samples in total)were studied.The DGEBA is the object of reference while the other three epoxy resin systems each have excellent performance that meets the requirements of spaceborne plastic packaging chip.After the irradiation,a significant darkening of colors and a decrease in the overall transparency of the tested samples are observed.However,the mechanical properties change dramatically with the increase of ? rays irradiation dose while their tensile strength and flexural strength of the samples change with an irregular variation trend.However,after 2.8MGy irradiation,the tensile strength and flexural strength of all the samples remain in a level similar to that before irradiation with no significant decline.Due to the crosslinking density decrease caused by chain scission,there is a mono tonic decrease of glass transition temperature(Tg)with the increase of y rays irradiation.Apart from DGEBA,the glass transition temperature(Tg)for the three newly-made samples is all above 220?,which shows good thermal stability.At the same time,under ? rays irradiation,changes of full width at half maximum and the chemical construction of the materials are analyzed.From the perspective of breaking and formation of chemical bonds,explanations about several property characterization changes are given.The results show that the addition of tetrafunctional epoxy resin can effectively improve the thermal stability of DGEBA epoxy resin under irradiation,and demonstrates its excellent anti-irradiation ability.In addition,it was found from the change in the full width at half maximum in dynamic thermodynamic properties showed that ? irradiation also reduced the uniformity of network of cured epoxy resins.