Aqueous tape casting of Al2O3-BBSZ based LTCC multilayer substrates

• Published in: Materials research bulletin 2021-08, Vol.140, p.111289, Article 111289
• Main Authors: Ann Jose, Sabitha, K.A., Krishnakumar, Kuzhichalil Peethambharan, Surendran
• Format: Article
• Language: English
• Subjects: Alumina; Aqueous tape casting; Bismuth borosilicate glass; Hazard -free processing; LTCC
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2021.111289

[Display omitted] •Hazard free aqueous tape casting protocol for Al2O3-BBSZ LTCC tapes.•Aqueous tapes of Al2O3-BBSZ LTCC show comparable properties with conventional LTCC tapes.•Optimized low temperature sintering of the glass-ceramic system at 900 °C.•Aqueous tapes have good control over solvent evaporation rates, yielding crack free microstructure. Several volatile organic compounds (VOCs) including xylene, methyl ethyl ketone (MEK) etc. are frequently used in organic tape casting slurries. Prolonged exposure to these VOCs can lead to appalling health hazards and hence should be avoided in future for the tape casting process to be environment friendly and sustainable. In the present research, we developed an aqueous tape casting protocol for Al2O3-BBSZ LTCC tapes, without using VOCs. The amount of water, binder, and plasticizers were suitably optimized to yield smooth and crack-free tapes. The impressive mechanical, thermal and dielectric properties (εr = 7.2 and tan δ = 10−2 at 5 GHz) reveal that the developed aqueous protocol for tape casting is ideal for generating sustainable hybrid electronic circuits operating at extreme conditions. To the best of our knowledge, this is the first successful attempt of hazard-free aqueous tape casting of alumina-glass ceramic composite for LTCC multilayer circuit applications.