CN-121585128-B - Highly integrated bulk acoustic wave resonator, filter and preparation method

CN121585128BCN 121585128 BCN121585128 BCN 121585128BCN-121585128-B

Abstract

The invention discloses a highly integrated bulk acoustic wave resonator, a filter and a preparation method, which belong to the technical field of filters, wherein the bulk acoustic wave resonator comprises an active area, a non-active area at least partially surrounding the active area, a substrate, a bottom electrode, a piezoelectric layer and a top electrode which are arranged in a stacking way along the longitudinal direction, a plane inductor, a dielectric layer and a capacitor electrode, the plane inductor and the top electrode are in the same layer, the dielectric layer is located on one side of the plane inductor and one side of the top electrode away from the piezoelectric layer, the capacitor electrode is arranged on one side of the dielectric layer and forms a capacitor structure with the top electrode, and the plane inductor and the capacitor structure are located in the non-active area and on two sides of the active area respectively. The invention is beneficial to realizing the miniaturization of the radio frequency device by integrating the inductor and the capacitor in the bulk acoustic wave resonator.

Inventors

XUAN WEIPENG
ZHANG WEIJUN
DING RUI
CHEN LONG
ZHENG PENG
LI WENJUN
SUN LINGLING
JIN HAO
DONG SHURONG

Assignees

杭州电子科技大学

Dates

Publication Date: 20260508
Application Date: 20260128

Claims (7)

1. The bulk acoustic wave resonator is characterized by comprising an active region, a non-active region at least partially surrounding the active region, a substrate, an acoustic mirror, a bottom electrode, a piezoelectric layer, a top electrode and a transition electrode which are arranged in a stacking manner along the longitudinal direction, wherein the active region is formed by overlapping parts of the acoustic mirror, the bottom electrode, the piezoelectric layer and the top electrode in the longitudinal direction, a plane inductor, a dielectric layer and a capacitance electrode, the plane inductor and the transition electrode are in the same layer as the top electrode, the dielectric layer is positioned on one side of the plane inductor and the side of the top electrode away from the piezoelectric layer, the capacitance electrode is arranged on one side of the dielectric layer and forms a capacitance structure with the top electrode, and the plane inductor and the capacitance structure are positioned on two sides of the non-active region and are respectively positioned on two sides of the active region; The bulk acoustic wave resonator further comprises a cover plate laminated on the dielectric layer, a groove is formed in one side of the dielectric layer away from the top electrode and/or one side of the cover plate close to the piezoelectric layer, and the capacitor electrode is arranged in the groove; the capacitor electrode comprises conductive adhesive, the groove is arranged on one side, far away from the top electrode, of the dielectric layer, the conductive adhesive is filled in the groove, the conductive adhesive is simultaneously bonded with one side, close to the piezoelectric layer, of the cover plate and the side wall of the groove, or the capacitor electrode comprises conductive adhesive, the groove is arranged on one side, close to the piezoelectric layer, of the cover plate, the conductive adhesive is filled in the groove, and the conductive adhesive is simultaneously bonded with one side, far away from the top electrode, of the dielectric layer and the side wall of the groove; The piezoelectric layer is provided with a first through hole, the first through hole penetrates through the piezoelectric layer, the cover plate and the dielectric layer form a second through hole, metal materials are filled in the first through hole and the second through hole, the bottom electrode is conducted to one side, far away from the piezoelectric layer, of the cover plate through the first through hole, the transition electrode and the second through hole, the capacitor electrode is conducted to one side, far away from the piezoelectric layer, of the cover plate through the second through hole, and the plane inductor is conducted to one side, far away from the piezoelectric layer, of the cover plate through the second through hole.
2. The highly integrated bulk acoustic resonator of claim 1, wherein the capacitive electrode comprises a conductive paste, the recess comprises a first recess and a second recess, the first recess is disposed on a side of the dielectric layer away from the top electrode, the second recess is disposed on a side of the cover plate adjacent to the piezoelectric layer, the first recess and the second recess are in communication, and the conductive paste is filled in the recess.
3. The highly integrated bulk acoustic wave resonator of claim 2, wherein the first and second grooves are offset from each other.
4. A bulk acoustic wave filter comprising the bulk acoustic wave resonator of any one of claims 1-3.
5. A method of manufacturing a bulk acoustic wave resonator, comprising: providing a first substrate; Sequentially forming an acoustic mirror, a bottom electrode film, a piezoelectric layer and a top electrode film on the first substrate, and patterning the top electrode film to form a top electrode, a transition electrode and a planar inductor; Forming a dielectric layer on the top electrode and the planar inductor, and patterning the dielectric layer to form a groove on one side of the dielectric layer far away from the top electrode, filling a capacitor electrode in the groove to enable the capacitor electrode and the top electrode to form a capacitor structure, and forming a cover plate on one side of the dielectric layer far away from the first substrate, wherein the bulk acoustic wave resonator comprises an active region and a non-active region at least partially surrounding the active region, the planar inductor and the capacitor structure are positioned in the non-active region and are respectively positioned on two sides of the active region, and overlapping parts of the acoustic mirror, the bottom electrode, the piezoelectric layer and the top electrode in the longitudinal direction form the active region; the capacitor electrode comprises conductive adhesive, the groove is arranged on one side, far away from the top electrode, of the dielectric layer, the conductive adhesive is filled in the groove, the conductive adhesive is simultaneously bonded with one side, close to the piezoelectric layer, of the cover plate and the side wall of the groove, or the capacitor electrode comprises conductive adhesive, the groove is arranged on one side, close to the piezoelectric layer, of the cover plate, the conductive adhesive is filled in the groove, and the conductive adhesive is simultaneously bonded with one side, far away from the top electrode, of the dielectric layer and the side wall of the groove; The piezoelectric layer is provided with a first through hole, the first through hole penetrates through the piezoelectric layer, the cover plate and the dielectric layer form a second through hole, metal materials are filled in the first through hole and the second through hole, the bottom electrode is conducted to one side, far away from the piezoelectric layer, of the cover plate through the first through hole, the transition electrode and the second through hole, the capacitor electrode is conducted to one side, far away from the piezoelectric layer, of the cover plate through the second through hole, and the plane inductor is conducted to one side, far away from the piezoelectric layer, of the cover plate through the second through hole.
6. The method of manufacturing according to claim 5, further comprising: Covering a second substrate on the capacitor electrode and the dielectric layer; Stripping the first substrate and patterning the bottom electrode film to form a bottom electrode; Forming a first through hole in the piezoelectric layer, and filling a conductive material in the first through hole to conduct a part of the bottom electrode and the top electrode film, wherein the bottom electrode and the top electrode are not electrically connected; bonding a third substrate on one side of the piezoelectric layer away from the top electrode; forming a plurality of second through holes on the second substrate and/or the dielectric layer, and filling conductive materials in the second through holes; And forming bonding pads connected with the second through holes in a one-to-one correspondence manner on one side of the second substrate far away from the third substrate, wherein the second through holes are used for respectively conducting the planar inductor, the first through holes, the top electrode, the capacitor electrode and the corresponding bonding pads.
7. The method of claim 6, wherein the step of forming a recess in a side of the dielectric layer remote from the top electrode comprises: Forming a groove on one side of the dielectric layer away from the top electrode, or Forming a groove on one side of the second substrate close to the piezoelectric layer, or And forming a first groove on one side of the dielectric layer far away from the top electrode, forming a second groove on one side of the second substrate close to the piezoelectric layer, and forming the grooves by the first groove and the second groove.

Description

Highly integrated bulk acoustic wave resonator, filter and preparation method Technical Field The invention relates to the technical field of filters, in particular to a highly integrated bulk acoustic wave resonator, a filter and a preparation method. Background In the prior art, the inductor and the capacitor are generally integrated at the input end/output end/ground end of the filter or integrated in the radio frequency front end module, so that the size of the filter or the radio frequency front end module can be greatly increased, the requirement of miniaturization of the current radio frequency device is not met, and meanwhile, the degree of freedom of integration of the capacitor and the inductor is limited. Disclosure of Invention The invention aims to provide a highly integrated bulk acoustic wave resonator, a filter and a preparation method thereof, which are used for solving the problem that the size of the filter is increased due to the fact that an inductor and a capacitor are integrated at the input end or the output end of the filter in the prior art. An object of the present invention is to provide a highly integrated bulk acoustic wave resonator, which includes an active region and an inactive region at least partially surrounding the active region, the bulk acoustic wave resonator further includes a substrate, a bottom electrode, a piezoelectric layer, and a top electrode that are stacked in a longitudinal direction, the bulk acoustic wave resonator further includes a planar inductor, a dielectric layer, and a capacitor electrode, the planar inductor and the top electrode are co-layered, the dielectric layer is located on a side of the planar inductor and the top electrode away from the piezoelectric layer, the capacitor electrode is disposed on a side of the dielectric layer and forms a capacitor structure with the top electrode, and the planar inductor and the capacitor structure are located in the inactive region and are located on two sides of the active region, respectively. Optionally, the bulk acoustic wave resonator further includes a cover plate laminated on the dielectric layer, a groove is formed on a side of the dielectric layer away from the top electrode and/or a side of the cover plate close to the piezoelectric layer, and the capacitor electrode is disposed in the groove. Optionally, the capacitor electrode includes conductive adhesive, the recess set up in the dielectric layer is kept away from one side of top electrode, conductive adhesive pack in the recess, conductive adhesive simultaneously with the apron be close to one side of piezoelectric layer with the lateral wall bonding of recess, or, the capacitor electrode includes conductive adhesive, the recess set up in the apron be close to one side of piezoelectric layer, conductive adhesive pack in the recess, conductive adhesive simultaneously with the dielectric layer is kept away from one side of top electrode with the lateral wall bonding of recess. Optionally, the capacitor electrode includes conductive adhesive, the groove includes a first groove and a second groove, the first groove is disposed on a side of the dielectric layer away from the top electrode, the second groove is disposed on a side of the cover plate close to the piezoelectric layer, the first groove is communicated with the second groove, and the conductive adhesive is filled in the groove. Optionally, the first groove and the second groove are offset from each other. An object of the present invention is to provide a highly integrated bulk acoustic wave resonator, including an active region and an inactive region at least partially surrounding the active region, the bulk acoustic wave resonator further including a substrate, a bottom electrode, a piezoelectric layer, and a top electrode stacked in a longitudinal direction, the bulk acoustic wave resonator further including a first capacitor and a second capacitor, one of a plate of the first capacitor and one of a plate of the second capacitor being co-layered with the top electrode, the bulk acoustic wave resonator further including a dielectric layer covering the top electrode, the other plate of the first capacitor and the other plate of the second capacitor being located on a side of the dielectric layer away from the top electrode, the first capacitor and the second capacitor being located on both sides of the inactive region and the active region, respectively. Another object of the present invention is to provide a bulk acoustic wave filter including the bulk acoustic wave resonator described above. Still another object of the present invention is to provide a method for manufacturing a bulk acoustic wave resonator, including: providing a first substrate; Sequentially forming a bottom electrode film, a piezoelectric layer and a top electrode film on the first substrate, and patterning the top electrode film to form a top electrode and a planar inductor; And forming a dielectric layer on th