Wafer level ultrasonic device

A wafer level ultrasonic device, comprising:

• a composite layer comprising an ultrasonic element and a protective layer, wherein the ultrasonic element comprises a first electrode and a second electrode, the first electrode is not connected to the second electrode, the protective layer covers the ultrasonic element and has a first connecting channel and a second connecting channel, one end of the first connecting channel corresponds the first electrode, and one end of the second connecting channel corresponds to the second electrode;
• a first conductive layer in the first connecting channel and electrically connected to the first electrode, wherein a first part of the first conductive layer is exposed to the protective layer;
• a second conductive layer in the second connecting channel and electrically connected to the second electrode, wherein a first part of the second conductive layer is exposed to the protective layer;
• a base connected to the protective layer, wherein the base comprises an opening, and the opening defines a closed cavity with the protective layer;
• a first electrical connection region, wherein the first electrical connection region extends through the base and is filled with a metal material to be electrically connected to the first conductive layer;
• and
• a second electrical connection region, wherein the second electrical connection region extends through the base and is filled with the metal material to be electrically connected to the second conductive layer.