Wafer level ultrasonic chip module having suspension structure
A wafer level ultrasonic chip module includes a substrate, a composite layer and a base material. The substrate has a through slot passing through an upper surface and a lower surface of the substrate. The composite layer includes an ultrasonic body and a protective layer. A lower surface of the ultrasonic body is exposed from the through slot. The protective layer covers the ultrasonic body and a partial upper surface of the substrate. The composite layer has a groove passing through an upper surface and a lower surface of the protective layer, and communicating with the through slot. Rhe ultrasonic body corresponds to the through slot. The base material covers the through slot, such that a space is formed among the through slot, the lower surface of the ultrasonic body and an upper surface of the base material.
1 . A wafer level ultrasonic chip module having a suspension structure, comprising:
a substrate comprising a through slot, the through slot passing through an upper surface of the substrate and a lower surface of the substrate;
a composite layer located on the substrate, the composite layer comprising an ultrasonic body and a protective layer, wherein the ultrasonic body is located on the upper surface of the substrate and a lower surface of the ultrasonic body is exposed from the through slot, the protective layer covers the ultrasonic body and a partial upper surface of the substrate, the composite layer has a groove, the groove passes through an upper surface of the protective layer and a lower surface of the protective layer, and communicates with the through slot, the groove surrounds a portion of the periphery of the ultrasonic body, and the ultrasonic body corresponds to the through slot; and
a base material located on the lower surface of the substrate and covering the through slot, such that a space is formed among the through slot, the lower surface of the ultrasonic body and an upper surface of the base material, and the space communicates with the groove.
2 . The wafer level ultrasonic chip module having a suspension structure according to claim 1 , wherein the ultrasonic body comprises:
a first piezoelectric layer located on the substrate;
a first electrode located on the first piezoelectric layer;
a second piezoelectric layer located on the first electrode; and
a second electrode located on the second piezoelectric layer, wherein the second piezoelectric layer and the second electrode do not cover a partial upper surface of the first electrode.
3 . The wafer level ultrasonic chip module having a suspension structure according to claim 2 , wherein the composite layer further comprises a circuit layer and two electrode circuits, the protective layer wraps the circuit layer and exposes a side surface of the circuit layer, the protective layer wraps the two electrode circuits, the two electrode circuits are located on the partial upper surface of the first electrode and a partial upper surface of the second electrode respectively, and the two electrode circuits are electrically connected with the first electrode and the second electrode respectively.
4 . The wafer level ultrasonic chip module having a suspension structure according to claim 3 , further comprising a conductor layer and at least one pad, wherein the conductor layer is located from the side surface of the circuit layer to a lower surface of the base material, and the at least one pad is located on the conductor layer.
5 . The wafer level ultrasonic chip module having a suspension structure according to claim 1 , wherein the ultrasonic body is located on the space and connected to the protective layer in a suspension manner, and the projection of the ultrasonic body and the projection of the space overlap in a vertical projection direction of the base material.
6 . The wafer level ultrasonic chip module having a suspension structure according to claim 1 , wherein the protective layer comprises an opening, a partial upper surface of the ultrasonic body is exposed from the opening, the wafer level ultrasonic chip module further comprises a conducting material, and the conducting material is located in the opening and is in contact with the upper surface of the ultrasonic body.