The use of a sol-gel processed cordierite precursor sinterable about$900^{circ}C$ allows cosintering of the copper and the ceramic. A strong bonding between the copper film and the cordierite substrate can be achieved through an eutectic bonding technique. These interfaces were investigated using STEM. copper diffusion as well as strong chemical and structural modifications was observed in the interface region. Although these interfaces have good adhesion properties, there was no evidence of the formation of the copper compound at the interface.