Preparation And Interfacial Compatibility Of CaO-B₂O₃-SiO₂ Glass-Ceramics For Dielectric Paste

With the rapid development of microelectronic package technology,the use of thick film hybrid integrated circuits is gradually expanding.High integration,high performance and high quality ceramic circuit board can be prepared by thick film technology.However,at present,there is a lack of systematic study on the thick film dielectric paste,the dielectric paste with glass powder,and interfacial compatibility between dielectric paste and conductive layer.Therefore,on the basis of fully understanding the preparation methods and application of glass powder in the paste and dielectric paste of thick film circuit,the crystallization and thermal properties of different CaO-B₂O₃-SiO₂?CBS?components were studied.On the basis of CBS system,other metal oxides?BaO and ZnO?were doped respectively to study their influence on the crystallization and thermal properties of CBS.Finally,the prepared glass is made into dielectric paste,and study the effect of its solid content on the rheological properties of the paste,the pressure resistance of the media layer and the interfacial compatibility?interfacial wetting and elemental diffusion?,so as to prepare the paste with good insulation and isolation.The results show that:?1?In the CBS system,the main crystal phase of 40%CaO-30%B₂O₃-30%SiO₂?mol?glass-ceramics is CaB₂O₄,and the thermal expansion coefficient is quite different from that of Al₂O₃ ceramic substrate;while the main crystalline phase of 40%CaO-20%B2O3-40%SiO2?mol?glass-ceramics is CaSiO₃?with excellent insulation and good dielectric properties?and has the same coefficient of thermal expansion as Al₂O₃.?2?Based on the glass composition of 40%CaO-20%B₂O₃-40%SiO₂?mol?glass,a certain amount of BaO with fluxing effect is introduced.With the increase of BaO content,the content of glassy phase in the glass-ceramics gradually increases,indicating that the introduction of Ba²⁺significantly reduces the crystallizing ability of glass-ceramics.When the content of BaO is 5%,the softening temperature?T_s?of the glass decreases from 902°C to 682°C.Meanwhile,it has good wetting property and matched thermal expansion with Al₂O₃ ceramic substrate.?3?In the CBS system,adding a certain amount of ZnO also reduces the crystallization of glass,while inhibiting the formation of?-CaSiO₃ phase and promote the formation of SiO₂.When 5%and 10%ZnO are added,the T_s decrease is not obvious,but the T_s decreases from876°C to 653°C when the ZnO content reaches 15%.?4?5%BaO and 15%ZnO,respectively,were added into the CBS glass and made into dielectric paste.When the dielectric layer thickness is up to30?m,withstand voltage can reach 2000v.Indicating that the prepared dielectric paste has good insulation properties.In addition,EDS analysis shows that the addition of ZnO,compared with BaO,can effectively suppress the diffusion of Ag.