Three-dimensional bulk acoustic wave resonator and manufacturing method thereof

Abstract

The invention discloses a three-dimensional (3D) bulk acoustic wave (BAW) resonator. The three-dimensional bulk acoustic wave resonator comprises a plurality of piezoelectric films which are vertically and horizontally distributed between a substrate and a cap layer, a plurality of first cavities are formed between the adjacent piezoelectric films in the vertical direction, a shared second cavityis formed between the adjacent piezoelectric films in the horizontal first direction, and a shared third cavity is formed between the adjacent piezoelectric films in the horizontal second direction; aplurality of electrode layers which at least cover the top surface and the bottom surface of each first cavity; and an electrode interconnection layer which is sequentially connected with the plurality of electrode layers along the side surface of the third cavity. According to the 3D BAW resonator and the manufacturing method thereof, the three-dimensional resonator with the multiple cavities surrounding the piezoelectric film is manufactured through the CMOS compatible process, the size is reduced, the integration degree is increased, and the cost is reduced.

Description

technical field [0001] The invention relates to a three-dimensional (3D) bulk acoustic wave (BAW) resonator and a manufacturing method thereof, in particular to a 3D BAW resonator compatible with a CMOS process and a manufacturing method thereof. Background technique [0002] In wireless communication, radio frequency filters are used as an intermediary for filtering specific frequency signals to reduce signal interference in different frequency bands, and to realize functions such as image elimination, spurious filtering, and channel selection in wireless transceivers. With the deployment of 4GLTE networks and the growth of the market, the design of RF front-ends is developing in the direction of miniaturization, low power consumption and integration, and the market has higher and higher requirements for filtering performance. Because the film bulk acoustic resonator (FilmBulkAcousticResonator, referred to as "FBAR", also known as "bulk acoustic wave", BulkAcousticWave, ref...

AI Technical Summary

Problems solved by technology

That is, BAW filters and bulk acoustic resonators (BARs) are not provided as structures integrated with other CMOS, BIiCMOS, SiGe HBT and / or passive devices, resulting in higher manufacturing costs and increased manufacturing process

[0005] In addition, as an independent device, the 2D BAW resonator has a large volume and area, and a low integration level. It is difficult to manufacture it on the same chip as its driving circuit using CMOS technology, and it is even more difficult to integrate with 3D devices such as FinFET and NAND memory.

However, if 3D packaging technology is used to stack multiple 2D BAW resonators together, although the integration level can be effectively improved, each chip needs to use bonding, back grinding and thinning (grinding) and through-silicon via (TSV) ) technology to reduce the package height, the process is complicated and requires extremely high alignment accuracy, and the manufacturing cost is high

In addition, this 3D package also has the problems of complex wiring and large parasitic impedance

Images