Research On The Sintering Shrinkage Property Of Cordierite Ceramic Tapes

High frequency technology acquired great application because of the developmentof communication technology. And it became the mainstream of the integration,microminiaturization, multi-functionalization and multiple-dimension of electronicproducts. Therefore, choosing suitable high frequency dielectric material, usinglow-temperature co-fired ceramics (LTCC) technology and designing the componentswith multilayer structure well complied this trend and are widely used in the practicalapplication. As one of the most critical problems, the control of ceramic substratecontraction is closely related to the ultimate quality of multilayer ceramic devices andceramic packaging substrate.According to the existing research results, under the premise of unchanging theformula of slurry, the effect of particle size and proportion of cordierite powders on thesintering shrinkage performance of tapes is investigated. The investigation is foundedon the basis of changing the proportion of cordierite powders and thus each componentof the slurry is changed relatively. The research is shown that cordierite powders withD(0.5)of4.033μm are suitable one for tape casting. With the increase of the proportionof cordierite, the compactness of the sintered tapes is according improved and shrinkageis decreased. In some content, the highest content of cordierite, the best of the surfaceand cross-section morphologies and the lowest of the shrinkage.Then, the effect of binder concentration on the sintering shrinkage of cordieriteceramic tapes is studied by adjusting the binder ratio of the slurry. The results show thatthe samples with5%PVA and6%PVA have ideal morphologies when they are sinteredat1000℃. The one with5%PVA has the minimum shrinkage when the sinteringtemperature is1000℃and the shrinkage rate is only26.58%.In the following, with the cordierite tapes prepared as matrix material, thecordierite ceramic tapes are laminated by cold press method. On this basis, the effect oflamination process on the sintering shrinkage of cordierite ceramic tapes is studied. Theresults show that pressure of lamination, dwell time and the layers of tapes are the main factors and in which dwell time has little impact and sintering temperature can affect thesample density. There would be the minimum shrinkage rate of24.15%when thesintering temperature is1000℃and the layer number is10, the pressure is7MPa and thedwell time is2min.Finally, on the basis of cold press lamination, a new method is chosen to restrictthe sintering shrinkage of cordierite tapes: pressure assisted sintering process. Theresults show that the compactness of samples produced by the sintering process is goodand the pressure of block is the main factor on the shrinkage of cordierite tapes of thelaminated sample. The longitudinal shrinkage rate of tapes would be greatly reduced toonly4.76%when the weight of pressure block is2.25kg at1000℃. Moreover, thesurface and cross-section of sintered sample is dense and no pores and cracks appear.There are also no deformation and wrapping detected.