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Low‐Temperature Co‐Fired Ceramic Substrates for High‐Performance Strain Gauges
Author(s) -
Brandt Bjoern,
Gemeinert Marion,
Rabe Torsten,
Bolte Jochen
Publication year - 2013
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/ijac.12052
Subject(s) - materials science , thin film , strain gauge , fabrication , ceramic , composite material , gauge factor , sintering , tape casting , lamination , foil method , thermal expansion , wafer , substrate (aquarium) , surface roughness , pressure sensor , optoelectronics , nanotechnology , mechanical engineering , medicine , oceanography , alternative medicine , pathology , layer (electronics) , geology , engineering
Recent advances in the development of high gauge factor thin films for strain gauges prompt the research on advanced substrate materials. A glass ceramic composite has been developed in consideration of a high coefficient of thermal expansion (9.4 ppm/ K ) and a low modulus of elasticity (82 GP a) for the application as support material for thin‐film sensors. In the first part, constantan foil strain gauges were fabricated from this material by tape casting, pressure‐assisted sintering, and subsequent lamination of the metal foil on the planar ceramic substrates. The accuracy of the assembled load cells corresponds to accuracy class C 6. That qualifies the load cells for the use in automatic packaging units and confirms the applicability of the low‐temperature co‐fired ceramic ( LTCC ) substrates for fabrication of accurate strain gauges. In the second part, to facilitate the deposition of thin‐film sensor structures to the LTCC substrates, pressure‐assisted sintering step is modified using smooth setters instead of release tapes, which resulted in fabrication of substrates with low average surface roughness of 50 nm. Titanium thin films deposited on these substrates as test coatings exhibited low surface resistances of 850 Ω comparable to thin films on commercial alumina thin‐film substrates with 920 Ω. The presented material design and advances in manufacturing technology are important to promote the development of high‐performance thin‐film strain gauges.