Prediction of shrinkage and deformation during LTCC device production

Aravind Mohanram, Gary Lynn Messing, David J. Green, Clive A. Randall

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


LTCC technology promises new applications in the wireless age. Advances in LTCC technology include improved characterization and precise modeling of the co-sintering process. In the present work, industrial LTCC systems such as DuPont 951, Heraeus CT2000, Ferro A6-S and silver have been evaluated for their thermo-mechanical properties, such as viscosity using cyclic loading dilatometry. The viscosities are used in Newtonian constitutive laws commonly used to simulate sintering. The viscosity decreases with temperature and increases with relative density and ranges from 0.1-100 GPa.s. Under isothermal conditions, the increase in viscosity is exponential as relative density increased to > 92%. Glass crystallization has a significant influence on the viscosity. Camber (warpage) evolution in LTCC/Ag systems was examined in real-time and correlated to viscosities of individual components. It was found that the rate of camber depends on: differential strain rate, relative viscosity and relative thickness of the co-fired components. For a given thickness ratio, the amount of camber can be kept to a minimum by optimizing the values of relative viscosity and matching the strain rates. Experimental observations show good agreement with previous theoretical models.

Original languageEnglish (US)
Pages (from-to)772-777
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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