Abstract: Acoustic wave devices are fabricated and packaged together while in wafer form. The devices are formed as dies on a first wafer, which may be quartz crystal. A second wafer, e.g., of alumina or another ceramic, has vias formed in it at positions that correspond to the locations of metallic bus bars on the first wafer, and a grid of an anisotropic conductive thermoplastic material is applied onto the second wafer. The two wafers are laminated, and treated with pressure and heat. The anisotropic conductive material seals the dies, and also connects the die bus bars through the vias to outside conductors. A thin passivation layer, e.g., SiO2, may provide hermetic sealing of the sensitive areas of the die. The devices may be tested robotically in wafer form before singulation.

Abstract: A bi-layer encapsulation system for a planar acoustic wave device, e.g., a SAW device, employs a layer of controlled particles to contact the active surface of the SAW device, and another layer to lock the first layer in place. A back surface of the device is bonded to a supporting substrate, e.g., a ceramic backing. The particles may be glass microspheres of a nominal 50 micron size. A layer of microspheres cover the acoustically active area of the device. Then, an epoxy or other suitable potting material covers the glass microspheres and bonds to the device and to the supporting substrate. The glass spheres may be solid glass or balloon-like microspheres filled with nitrogen or another gas. A second layer of glass microspheres may be applied over the first layer and around the edges of the first layer. This layer may contain an appropriate B-stage epoxy or a commercially available syntactic foam material. A plurality of devices can be packaged and encapsulated together while in wafer form.

Abstract: A bi-layer encapsulation system for a planar acoustic wave device, e.g., a SAW device, employs a layer of controlled particles to contact the active surface of the SAW device, and another layer to lock the first layer in place. A back surface of the device is bonded to a supporting substrate, e.g., a ceramic backing. The particles may be glass microspheres of a nominal 50 micron size. A layer of microspheres cover the acoustically active area of the device. Then, an epoxy or other suitable potting material covers the glass microspheres and bonds to the device and to the supporting substrate. The glass spheres may be solid glass or balloon-like microspheres filled with nitrogen or another gas. A second layer of glass microspheres may be applied over the first layer and around the edges of the first layer. This layer may contain an appropriate B-stage epoxy or a commercially available syntactic foam material. A plurality of devices can be packaged and encapsulated together while in wafer form.

Abstract: A SAW reflector structure located between multiple interdigitated generator/receivers located on a piezo-electric substrate forming a ladder type SAW device is described. The reflector structure reduces both reflections due to mechanical-electrical loading from the physical presence of generator/receiver fingers without using a split finger arrangement as well as reflections due to the regenerated reflection from the generator/receiver. The reflector has a first acoustic phase center. The generator/receiver has a second acoustic phase center, a regenerated voltage coefficient of reflection, r.sub.e and a mechanical-electrical loading coefficient of reflection, r.sub.m. The reflector is used for simultaneously reflecting both regenerated and mechanical-electrical loading induced reflections from the generator/receiver. The reflector is sized for a strength of reflection equal to the square root of the sum of the regenerated and mechanical-electrical loading reflections squared.