WO2021189965A1

WO2021189965A1 - Film bulk acoustic resonator and manufacturing method therefor

Info

Publication number: WO2021189965A1
Application number: PCT/CN2020/135672
Authority: WO
Inventors: 黄河; 罗海龙; 李伟
Original assignee: 中芯集成电路（宁波）有限公司
Priority date: 2020-03-27
Filing date: 2020-12-11
Publication date: 2021-09-30
Also published as: CN112039484A

Abstract

A film bulk acoustic resonator and a manufacturing method therefor. The film bulk acoustic resonator comprises: a bearing substrate, the bearing substrate comprising a first semiconductor layer (100A) and a first device layer (100B); a first micro device (1000), the first micro device (1000) being embedded in the bearing substrate, and at least a part of the first micro device (1000) being located in the first device layer (100B); a dielectric layer (102), bonded onto the first device layer (100B), the dielectric layer (102) encloses to form a first cavity (110a), the first cavity (110a) exposing from the surface of the bearing substrate; a piezoelectric lamination structure, covering the first cavity (110a), the piezoelectric lamination structure comprising, from bottom to top, a first electrode (103), a piezoelectric layer (104) and a second electrode (105) stacked sequentially; the first cavity (110a) being formed before the piezoelectric lamination structure and located below the piezoelectric lamination structure; and a first electrical connection structure, being connected to the first micro device (1000) and electrically leading out the first micro device (1000).

Description

Thin film bulk acoustic wave resonator and manufacturing method thereof

Technical field

The invention relates to the field of semiconductor device manufacturing, in particular to a thin-film bulk acoustic wave resonator and a manufacturing method thereof.

Background technique

With the continuous development of wireless communication technology, in order to meet the multi-functional requirements of various wireless communication terminals, terminal equipment needs to be able to use different carrier frequency spectrums to transmit data. At the same time, in order to support sufficient data transmission rates within a limited bandwidth, The radio frequency system also puts forward strict performance requirements. The radio frequency filter is an important part of the radio frequency system. It can filter out the interference and noise outside the communication spectrum to meet the requirements of the radio frequency system and the communication protocol for the signal-to-noise ratio. Taking a mobile phone as an example, since each frequency band needs a corresponding filter, dozens of filters may need to be set in a mobile phone.

Generally, the thin film bulk acoustic wave resonator includes two thin film electrodes, and a piezoelectric thin film layer is arranged between the two thin film electrodes. Its working principle is to use the piezoelectric thin film layer to generate vibration under an alternating electric field. The bulk acoustic wave propagating in the thickness direction of the electric film layer is transmitted to the interface between the upper and lower electrodes and the air to be reflected back, and then reflected back and forth inside the film to form an oscillation. When the sound wave propagates in the piezoelectric film layer exactly an odd multiple of the half wavelength, a standing wave oscillation is formed.

technical problem

However, the traditionally manufactured cavity-type thin-film bulk acoustic resonator, due to the limitation of the cavity formation process, cannot integrate micro devices in the substrate under the cavity, and can only achieve related functions by connecting the resonator with an external device, resulting in the device The large volume and long leads make the integration of the resonator not high and cannot meet the demand for miniaturization of the device.

Technical solutions

The invention discloses a thin film bulk acoustic wave resonator and a manufacturing method thereof, which can solve the problem of low integration of the thin film bulk acoustic wave resonator.

In order to solve the above technical problems, the present invention provides a thin film bulk acoustic wave resonator, including:

A carrier substrate, the carrier substrate including a first semiconductor layer and a first device layer;

A first micro device, the first micro device is embedded in the carrier substrate, and at least part of the first micro device is located in the first device layer;

A dielectric layer, bonded to the first device layer, the dielectric layer encloses a first cavity, and the first cavity exposes the surface of the carrier substrate;

The piezoelectric laminate structure covers the first cavity, and the piezoelectric laminate structure includes a first electrode, a piezoelectric layer, and a second electrode stacked in sequence from bottom to top; the first cavity is formed in the Located below the piezoelectric laminate structure before the piezoelectric laminate structure;

The first electrical connection structure connects the first micro-device and electrically leads the first micro-device.

The present invention also provides a method for manufacturing the film bulk acoustic resonator, which includes:

Provide temporary substrate;

Forming a piezoelectric laminate structure on the temporary substrate, the piezoelectric laminate structure including a second electrode, a piezoelectric layer, and a first electrode arranged in sequence from bottom to top;

Forming a dielectric layer to cover the piezoelectric laminate structure;

Patterning the dielectric layer to form a first cavity, and the first cavity penetrates the dielectric layer;

A carrier substrate is provided, the carrier substrate includes a first semiconductor layer and a first device layer, the first surface of the carrier substrate is embedded with a first micro device, and the side where the first device layer is The side where the first surface is located;

Bonding the carrier substrate to the dielectric layer, covering the first cavity, and making the first surface face the first cavity;

Removing the temporary substrate;

A first electrical connection structure is formed, and the first micro device is electrically connected to an external signal.

Beneficial effect

The beneficial effects of the present invention are:

Before bonding the carrier substrate, the first micro-device is formed in the carrier substrate in advance, which is separated from the manufacture of the resonator, and the process time is shortened. The micro device can be fabricated separately, and does not need to be fabricated in the resonator manufacturing process, so that the resonator structure is prevented from being subjected to the process environment when the micro device is fabricated, and the stability of the resonator is improved. Since this structure bonds the carrier substrate to the dielectric layer by bonding, it is possible to pre-form the first micro-device in the carrier substrate.

Further, micro devices are also formed in the cover substrate, which further improves the integration degree of the resonator.

Further, the dielectric layer and the bonding surface of the carrier substrate (the first device layer) are made of the same material, and can be directly bonded through atomic bonds, which improves the bonding strength and simplifies the process flow.

Furthermore, the first conductive plug and the second conductive plug are located on the same side of the resonator, which facilitates the manufacturing process of the process.

Further, the protrusions are arranged along the boundary of the effective resonance area to make the acoustic impedance mismatch between the inside of the effective resonance area and the area where the protrusions are located, effectively preventing the lateral leakage of sound waves, and improving the quality factor of the resonator;

Further, the effective resonance area of the resonator is defined by the first groove and the second groove. The first groove and the second groove respectively penetrate the first electrode and the second electrode, and the piezoelectric layer maintains a complete film layer. After etching, the structural strength of the resonator is ensured, and the yield of manufacturing the resonator is improved.

Description of the drawings

Through a more detailed description of the exemplary embodiments of the present invention in conjunction with the accompanying drawings, the above and other objectives, features and advantages of the present invention will become more apparent. In the exemplary embodiments of the present invention, the same reference numerals generally represent the same components. .

FIG. 1 shows a schematic diagram of the structure of a thin film bulk acoustic resonator of Embodiment 1. As shown in FIG.

2 to 11 show schematic structural diagrams corresponding to different steps of a method for manufacturing a thin-film bulk acoustic resonator according to the second embodiment.

Description of reference signs:

100A-first semiconductor layer; 100B-first device layer; 1000-first micro device; 1001-first conductive plug; 101-bonding layer; 102 dielectric layer; 103-first electrode; 104-piezoelectric layer 105-second electrode; 106-bonding layer; 110a-first cavity; 110b-second cavity; 120-conductive interconnection structure; 130a-first trench; 130b-second trench; 141-th A conductive interconnection layer; 142-first conductive bump; 151-second conductive interconnection layer; 152-second conductive bump; 160-insulating layer; 200A-second semiconductor layer; 200B-second device layer; 2000-Second Micro Device; 2001-Second Conductive Plug; 40-Bump; 300-Temporary Substrate.

Embodiments of the present invention

Hereinafter, the present invention will be further described in detail with reference to the drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present invention will be clearer. However, it should be noted that the concept of the technical solution of the present invention can be implemented in many different forms and is not limited to the specific implementation set forth herein. example. The drawings all adopt a very simplified form and all use imprecise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" other elements or layers, it can be directly on the other elements or layers. On a layer, adjacent to, connected or coupled to other elements or layers, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers. Floor. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or section discussed below may be represented as a second element, component, region, layer or section.

Spatial relationship terms such as "under", "below", "below", "below", "above", "above", etc., in It can be used here for the convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatial relationship terms are intended to include different orientations of devices in use and operation. For example, if the device in the figure is turned over, then elements or features described as "under" or "below" or "under" other elements will be oriented "on" the other elements or features. Therefore, the exemplary terms "below" and "below" can include both an orientation of above and below. The device can be otherwise oriented (rotated by 90 degrees or other orientation) and the spatial descriptors used here are interpreted accordingly.

The purpose of the terms used here is only to describe specific embodiments and not as a limitation of the present invention. When used herein, the singular forms "a", "an" and "the/the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "composition" and/or "including", when used in this specification, determine the existence of the described features, integers, steps, operations, elements and/or components, but do not exclude one or more other The existence or addition of features, integers, steps, operations, elements, parts, and/or groups. As used herein, the term "and/or" includes any and all combinations of related listed items.

If the method herein includes a series of steps, and the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some steps may be omitted and/or some other steps not described herein may be added to this method. If the components in a certain drawing are the same as those in other drawings, although these components can be easily identified in all the drawings, in order to make the description of the drawings more clear, this specification will not describe all the same components. The reference numbers are shown in each figure.

Example 1

This embodiment provides a thin film bulk acoustic wave resonator. FIG. 1 shows a schematic structural diagram of a thin film piezoelectric acoustic resonator of Embodiment 1. Please refer to FIG. 1. The thin film bulk acoustic wave resonator includes:

A carrier substrate, which includes a first semiconductor layer 100A and a first device layer 100B;

A first micro device 1000, the first micro device 1000 is embedded in the carrier substrate, and at least part of the first micro device 1000 is located in the first device layer 100B;

The dielectric layer 102 is bonded to the first device layer 100B, the dielectric layer 102 encloses a first cavity 110a, and the first cavity 110a exposes the surface of the carrier substrate;

The piezoelectric laminate structure covers the first cavity 110a. The piezoelectric laminate structure includes a first electrode 103, a piezoelectric layer 104, and a second electrode 105 that are sequentially stacked from bottom to top. The first cavity 110a is formed before the piezoelectric laminate structure, and is located under the piezoelectric laminate structure;

The first electrical connection structure is connected to the first micro-device, and the first electrical connection structure is used to supply power to the first micro-device.

It should be noted that the first cavity 110a is formed before the piezoelectric laminate structure, and is located below the piezoelectric laminate structure for explanation as follows: In the prior art, the manufacturing process of the resonator is: The substrate is etched to form a cavity, the sacrificial layer material is filled in the cavity, and a piezoelectric laminate structure is formed above the sacrificial layer material and the substrate. After the sacrificial layer is released, a lower cavity is formed, and the piezoelectric laminate structure is suspended below Above the cavity. After the piezoelectric laminate structure is formed, a capping layer may be formed on the upper surface of the piezoelectric laminate, and the cavity between the capping layer and the piezoelectric laminate structure is the upper cavity. The first cavity of the present invention corresponds to the lower cavity. The carrier substrate of this embodiment is bonded to the dielectric layer after the first cavity is formed. The carrier substrate needs to provide better support for the patterning process of the second electrode of the resonator, the production and patterning of the bonding layer, the production/grinding of the capping layer, or the production of the second electrical connection structure. Since this structure bonds the carrier substrate to the dielectric layer by bonding, it is possible to pre-form the first micro-device in the carrier substrate. The lower cavity is formed by the sacrificial layer method, and the micro device cannot be formed at the bottom of the lower cavity. Before bonding the carrier substrate, the first micro-device is formed in the carrier substrate in advance to shorten the process time. The micro device can be fabricated separately, and does not need to be fabricated in the resonator manufacturing process, so that the resonator structure is prevented from being subjected to the process environment when the micro device is fabricated, and the stability of the resonator is improved.

Specifically, in this embodiment, the carrier substrate includes a first semiconductor layer 100A and a first device layer 100B. The first device layer 100B is close to the side where the first cavity 110a is located, and the first micro device 1000 It is at least partially formed in the first device layer 100B. The first micro-device 1000 includes: a diode, a triode, a MOS transistor, an electrostatic discharge protection device, a resistor, a capacitor, or an inductor. When the first micro device 1000 is a resistor, a capacitor, or an inductor, the first micro device 1000 may all be located in the device layer 100B. When the first micro device 1000 is a triode or a MOS transistor, its source and drain levels It may be located in the first semiconductor layer 100A.

The material of the first semiconductor layer 100A includes silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs) , Indium Phosphide (InP) or other III/V compound semiconductors. The material of the first device layer 100B includes silicon oxide, silicon nitride, silicon oxynitride, and silicon carbonitride. The first device layer 100B and the dielectric layer 102 are combined by bonding. The material of the dielectric layer 102 may be any suitable dielectric material, including but not limited to silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, or ethyl silicate. When the materials of the first device layer 100B and the dielectric layer 102 are the same, atomic bonding can be used to directly bond. When the materials of the first device layer 100B and the dielectric layer 102 are different, a bonding layer can be formed on the bonding surface of the two. The materials of the bonding layer include silicon oxide, silicon nitride, polysilicon, and ethyl silicate. Or organic cured film. In this embodiment, the first device layer 100B and the dielectric layer are both silicon oxide, and atomic bonds are used for bonding, the bonding structure is strong and the process flow is simple. When bonding is performed through a bonding layer, a bonding layer structure is formed between the dielectric layer 101 and the carrier substrate. It can be seen from the materials of the dielectric layer and the bonding layer that the materials of the two may be the same or different.

In this embodiment, the first cavity 110a is a closed cavity, and the first cavity 110a may be formed by etching the dielectric layer 102 through an etching process. The shape of the bottom surface of the first cavity 110a is a rectangle, but in other embodiments of the present invention, the shape of the first cavity 110a on the bottom surface of the first electrode 103 may also be a circle, an ellipse, or a polygon other than a rectangle. For example, pentagons, hexagons, etc.

A piezoelectric stack structure is provided above the first cavity 110a, and the piezoelectric stack structure includes a first electrode 103, a piezoelectric layer 104, and a second electrode 105 in order from bottom to top. The first electrode 103 is located on the dielectric layer 102, the piezoelectric layer 104 is located on the first electrode 103, and the second electrode 105 is located on the piezoelectric layer 104. The first electrode 103, the piezoelectric layer 104, and the second electrode 105 above the first cavity 110a are provided with an overlapping area in the direction perpendicular to the carrier substrate 100 as an effective resonant area, and the boundary of the effective resonant area is located at all. In the area surrounded by the first cavity 110a. The shape of the effective resonance region is an irregular polygon, such as a pentagon or hexagon without parallel opposite sides.

In this embodiment, the piezoelectric layer 104 covers the first cavity 110a, and covering the first cavity 110a should be understood to mean that the piezoelectric layer 104 is a complete film layer and has not been etched. It does not mean that the piezoelectric layer 104 completely covers the first cavity 110a to form a sealed cavity. Of course, the piezoelectric layer 104 can completely cover the first cavity 110a to form a sealed cavity. The piezoelectric layer is not etched to ensure that the piezoelectric laminated structure has a certain thickness, so that the resonator has a certain structural strength. Improve the yield of resonators.

In one embodiment, an etch stop layer is further provided between the dielectric layer 102 and the first electrode 103, and its material includes but is not limited to silicon nitride (Si3N4) and silicon oxynitride (SiON). On the one hand, the etch stop layer can be used to increase the structural stability of the final manufactured thin film bulk acoustic wave resonator. On the other hand, the etch stop layer has a lower etching rate than the dielectric layer 102, and can be used to etch the dielectric layer. The layer 102 prevents over-etching during the process of forming the first cavity 110a, and protects the surface of the first electrode 103 located thereunder from damage, thereby improving the performance and reliability of the device.

In this embodiment, the upper part of the piezoelectric laminate structure includes a bonding layer 106, the bonding layer 106 encloses a second cavity 110b, and the second cavity 110b exposes the surface of the piezoelectric laminate structure. The second cavity 110b is located above the first cavity 110a. It also includes a cover substrate, which is disposed on the bonding layer 106 and covers the second cavity 110b. In this embodiment, a second micro device 2000 is embedded in the cover substrate on the side close to the second cavity 110 b.

In this embodiment, the cover substrate has a double-layer structure, and includes a second semiconductor layer 200A and a second device layer 200B. The second device layer 100B is close to the side where the second cavity 110b is located, and the first micro device 1000 is at least partially formed in the second device layer 200B. For the type of the second micro-device 1000 and the positional relationship with the cover substrate, refer to the related description of the type of the first micro-device 1000 and the positional relationship with the carrier substrate. For the optional material of the second semiconductor layer 200A, refer to the first semiconductor layer 100A. For the material types of the second device layer 200B, refer to the material types of the first device layer 100B, which will not be repeated here. The bonding layer 106 can be made of conventional bonding materials, such as silicon oxide, silicon nitride, silicon oxynitride, ethyl silicate, etc., or a bonding agent such as a light-curing material or a heat-curing material, such as an adhesive film (DieAttachFilm, DAF) or dry film (DryFilm), the production and patterning process is relatively simple. The material of the bonding layer and the material of the capping substrate 200 may be the same, and the two are an integral structure, and the second cavity 110b is formed by forming a space in the film layer (forming the bonding layer 106 and the capping substrate 200).

In order to supply power to the first micro device 1000 and the second micro device 2000, the resonator further includes a first electrical connection structure connected to the first micro device 1000 and a second electrical connection structure connected to the second micro device 2000. This embodiment Among them, the first electrical connection structure is a first conductive plug 1001, and the second electrical connection structure is a second conductive plug 2001.

In this embodiment, the first conductive plug 1001 extends from the bottom surface of the carrier substrate to the first micro device 1000. The second conductive plug 2001 extends from the bottom surface of the carrier substrate to the second micro device 2000.

In another embodiment, the first conductive plug may extend from the top surface of the cover substrate to the first micro device. The second conductive plug also extends from the top surface of the cover substrate to the second micro device. In the above two cases, the two conductive plugs are electrically connected to the micro device from the same side of the resonator. The main consideration is that when the conductive plug is made, the opposite side of the conductive plug needs to be supported with a certain strength. When making conductive plugs, the side of the conductive plug (carrier substrate or cover substrate) needs to be thinned, and the thickness is about 100 microns. The opposite side of the conductive plug (carrier substrate or cover substrate) is not The thickness is about a few hundred microns to provide a certain strength support for the manufacturing process. Of course, if the process conditions permit, the first conductive plug and the second conductive plug may be disposed on opposite sides of the resonator. In an embodiment, it may further include a third electrical connection structure, such as a third conductive plug, which electrically connects the first micro-device and the second micro-device.

In this embodiment, it also includes a first electrode lead-out part and a second electrode lead-out part. The first electrode lead-out part is used to introduce electrical signals into the first electrode 103 in the effective resonance region, and the second electrode lead-out portion is used to lead electrical signals into the first electrode 103 in the effective resonance region. The second electrode 105 in the effective resonance region. After the first electrode 103 and the second electrode 105 are energized, a pressure difference is generated on the upper and lower surfaces of the piezoelectric layer 104, forming a standing wave oscillation. The conductive interconnect structure 120 is used to short-circuit the first electrode and the second electrode outside the effective resonance region. It can be seen from the figure that the effective resonance region also includes the area where the piezoelectric layer, the first electrode, and the second electrode overlap each other in the direction perpendicular to the piezoelectric layer. When the first electrode and the second electrode are energized, the pressure difference between the upper and lower surfaces of the piezoelectric layer outside the effective resonance region can also be generated, and standing wave oscillation is also generated. However, the standing wave oscillation outside the effective resonance region is undesirable. For example, the first electrode and the second electrode outside the effective resonance area are short-circuited to make the upper and lower voltages of the piezoelectric layer outside the effective resonance area consistent, and no standing wave oscillation can be generated outside the effective resonance area, which improves the Q value of the resonator. The specific structures of the first electrode lead-out part, the second electrode lead-out part and the conductive interconnection structure 120 are as follows:

The first electrode lead-out part includes:

A first through hole 140, which penetrates through the lower layer structure of the first electrode 103 outside the effective resonance region, exposing the first electrode 103; a first conductive interconnection layer 141, covering the first electrode 103 The inner surface of a through hole 140 and a part of the surface of the carrier substrate 100 on the outer periphery of the first through hole 140 are connected to the first electrode 103; an insulating layer 160 covers the first conductive interconnection layer 141 and The surface of the carrier substrate 100; the conductive bumps 142 are arranged on the surface of the carrier substrate 100 and are electrically connected to the first conductive interconnection layer 141.

The second electrode lead-out part includes:

The second through hole 150, the second through hole 150 penetrates the lower structure of the first electrode 103 outside the effective resonance area, exposing the first electrode 103; the second conductive interconnection layer 151 covers the first electrode 103 The inner surface of the two through holes 150 and a part of the surface of the carrier substrate 100 on the periphery of the second through hole 150 are connected to the first electrode 103; an insulating layer 160 covers the second conductive interconnection layer 151 and The surface of the carrier substrate 100; second conductive bumps 152 are arranged on the surface of the carrier substrate 100 and are electrically connected to the second conductive interconnection layer 151.

In this embodiment, a protrusion 40 is provided at the boundary of the effective resonance region, and the protrusion 40 is provided on the upper surface or the lower surface of the piezoelectric laminated structure; or, the protrusion 40 is partially provided on the piezoelectric The upper surface of the laminated structure is partially disposed on the lower surface of the piezoelectric laminated structure.

In this embodiment, all the protrusions 40 are located on the lower surface of the piezoelectric laminate structure. All are located on the side where the first cavity 110a is located. The area surrounded by the protrusion 40 is an effective resonance area, and the outside of the protrusion 40 is an ineffective resonance area. The first electrode 103, the piezoelectric layer 104, and the second electrode 105 in the effective resonance area overlap each other in a direction perpendicular to the carrier substrate 100. In other embodiments, the protrusions 40 may all be located on the upper surface of the piezoelectric laminate structure, away from the side where the first cavity 110a is located. The protrusions 40 may also be partly arranged on the upper surface of the piezoelectric laminated structure and partly arranged on the lower surface of the piezoelectric laminated structure.

In this embodiment, the projection of the protrusion 40 on the supporting substrate 100 forms a closed ring, such as a closed irregular polygon, a circle, or an ellipse. The protrusion 40 causes the internal effective resonance area and the area where the protrusion 40 is located to mismatch the acoustic impedance, which can effectively prevent the lateral leakage of sound waves and improve the quality factor of the resonator. In other embodiments, the projection of the protrusion 40 on the carrier substrate 100 may not be a completely closed pattern. It should be understood that when the projection of the protrusion 40 on the carrier substrate 100 is a closed pattern, it is more beneficial to prevent the lateral leakage of sound waves.

The material of the protrusion 40 may be a conductive material or a dielectric material. When the material of the protrusion 40 is a conductive material, it may be the same as the material of the first electrode 103 or the second electrode 105. When the material of the protrusion 40 is In the case of the dielectric material, it can be any one of silicon oxide, silicon nitride, silicon oxynitride, or silicon carbonitride, but is not limited to the above materials.

In this embodiment, the surface of the piezoelectric laminate structure further includes a first groove 130a and a second groove 130b. The first groove 130a is located on the lower surface of the piezoelectric laminate structure on the side where the first cavity 110a is located. , Penetrates the first electrode 103 and surrounds the outer circumference of the area where the protrusion 40 is located. The second groove 130b is located on the upper surface of the piezoelectric laminate structure, penetrates the second electrode 105, and surrounds the outer circumference of the area where the protrusion 40 is located. The two ends of the first groove 130a and the two ends of the second groove 130b are arranged opposite to each other, so that the projections of the first groove 130a and the second groove 130b on the carrier substrate 100 The two junctions meet or have a gap. In this embodiment, the projection of the protrusion 40 on the piezoelectric layer 104 is a closed polygon, and the inner edges of the first groove 130a and the second groove 130b are arranged along the outer boundary of the protrusion 40, that is, The outer boundary of the protrusion 40 coincides with the inner edges of the first groove 130a and the second groove 130b. The projections of the first grooves 130a and the second grooves 130b on the carrier substrate 100 are closed patterns, consistent with the shape of the projections 40 projected on the carrier substrate 100, and are located on the outer periphery of the projections formed by the projections 40 .

It should be understood that the protrusions 40 are ring-shaped (when the protrusions 40 are all located on the lower or upper surface of the piezoelectric laminate structure, the protrusions 40 constitute a ring; when the protrusions 40 are located on both surfaces of the piezoelectric laminate structure, The projections of the two parts together form an overall ring). When all the protrusions 40 are located on the upper or lower surface of the piezoelectric laminate structure, the first groove 130a surrounds part of the outer circumference of the protrusion 40, and the second groove 130b surrounds the outer circumference of the remaining part of the protrusion 40 (here When the second groove 130b surrounds the outer circumference of the protrusion 40 means that it surrounds the outer circumference of the surface of the piezoelectric laminate structure in the area of the protrusion 40, and does not directly surround the outer circumference of the protrusion 40). When the protrusion 40 is partially disposed on the upper surface of the piezoelectric laminate structure and partially disposed on the lower surface of the piezoelectric laminate structure, the first groove 130a may surround the piezoelectric laminate structure. On the outer circumference of the protrusion 40 on the surface, the second groove 130b may surround the outer circumference of the protrusion 40 on the upper surface of the piezoelectric laminate structure. However, the present invention is not limited to this, as long as the first groove 130a and the second groove 130b cooperate with each other to surround the outer circumference of the area where the protrusion 40 is located.

The protrusion 40 causes the acoustic impedance of the inner region of the protrusion to be mismatched with the acoustic impedance of the area where the protrusion is located, and defines the boundary of the effective resonance region of the resonator. The first groove 130a and the second groove 130b separate the first electrode 103 and the second electrode 105, respectively, so that the resonator cannot meet the working conditions (the working condition is that the first electrode 103, the piezoelectric layer 104 and the second electrode 105 are in The thickness direction overlaps each other), which further defines the boundary of the effective resonance region of the resonator. The protrusion 40 causes the acoustic impedance to be mismatched by the addition of the mass. The first groove 130a and the second groove 130b make the electrode end face contact with the air to make the acoustic impedance mismatch, and both play a role in preventing the leakage of the transverse wave. Improve the Q value of the resonator. Of course, in other embodiments, only the first trench 130a or the second trench 130b may be provided separately. Since the first electrode 103 and the second electrode 105 need to introduce electrical signals, the first trench 130a or the second trench 130b is not suitable to form a closed ring, and at this time, the first groove 130a or the second groove 130b cannot completely surround the area where the protrusion 40 is located. The first groove 130a or the second groove 130b may be formed into a nearly closed ring shape, and the non-closed area is used to introduce electrical signals. This arrangement can simplify the process flow and reduce the cost of the resonator.

In this embodiment, it further includes a conductive interconnection structure 120. The conductive interconnection structure 120 includes two parts. It is electrically connected to the first electrode lead-out part. The other part of the conductive interconnect structure 120 is disposed in the outer area of the first trench 130a, connects the first electrode 103 and the second electrode 105, and is electrically connected to the second electrode lead-out portion through the first electrode 103. Both parts of the conductive interconnection structure 120 are provided with a region covering part of the surface of the second electrode 105. This region increases the contact area with the second electrode 105, reduces the contact resistance, and can prevent local high temperature caused by excessive current.

It should be noted that the second electrode lead-out portion is not directly electrically connected to the second electrode, but is connected to the first electrode outside the effective resonance region, and is electrically connected to the second electrode of the effective resonance region through the conductive interconnection structure 120. It can be seen that the first electrode lead-out part and the second electrode lead-out part are identical in structure, but the positions are different. The first electrode lead-out part is electrically connected to the first electrode inside the effective resonance zone, giving the first electrode lead-out part inside the effective resonance zone. One electrode is powered, and the first electrode lead part is electrically connected to the second electrode outside the effective resonance area through the first electrode outside the effective resonance area and the conductive interconnection structure 120, and is not connected to the second electrode inside the effective resonance area. In the same way, the second electrode lead-out portion is connected to the first electrode outside the effective resonance area and the second electrode inside the effective resonance area to realize power supply to the second electrode inside the effective resonance area.

Example 2

Embodiment 2 provides a method for manufacturing a thin film bulk acoustic resonator, including the following steps:

S01: Provide temporary substrate;

S02: forming a piezoelectric laminate structure on the temporary substrate, the piezoelectric laminate structure including a second electrode, a piezoelectric layer, and a first electrode arranged in sequence from bottom to top;

S03: forming a dielectric layer to cover the piezoelectric laminate structure;

S04: Pattern the dielectric layer to form a first cavity, and the first cavity penetrates the dielectric layer;

S05: Provide a carrier substrate, the carrier substrate includes a first semiconductor layer and a first device layer, the first surface of the carrier substrate is embedded with a first micro device, and the side where the first device layer is located is the carrier The side where the first surface of the substrate is located;

S06: Bond the carrier substrate to the dielectric layer, cover the first cavity, and make the first surface face the first cavity;

S07: Remove the temporary substrate;

S08: Form a first electrical connection structure to electrically connect the first micro-device with an external signal.

It should be noted that SON is not used to limit the sequence of steps. 2 to 11 show schematic diagrams of the structure at different stages of a method for manufacturing a thin film piezoelectric acoustic resonator according to Embodiment 2 of the present invention. Please refer to FIGS. 2 to 11 to describe each step in detail.

Referring to FIG. 2, step S01 is performed: a temporary substrate 300 is provided.

The temporary substrate 300 may be at least one of the materials mentioned below: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), silicon germanium (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III/V compound semiconductors, can also be ceramic substrates such as alumina, quartz or glass substrates, etc.

Referring to FIG. 3, perform step S02: forming a piezoelectric laminate structure on the temporary substrate 300, the piezoelectric laminate structure including a second electrode 105, a piezoelectric layer 104, and a first electrode arranged in sequence from bottom to top 103.

The materials of the second electrode 105 and the first electrode 103 can use any suitable conductive material or semiconductor material well known to those skilled in the art, wherein the conductive material can be a metal material with conductive properties, for example, made of molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd) and other metals or laminates of the above metals, semiconductor materials such as Si, Ge, SiGe, SiC, SiGeC, etc. . The second electrode 105 and the first electrode 103 may be formed by physical vapor deposition or chemical vapor deposition methods such as magnetron sputtering, evaporation, or the like. The material of the piezoelectric layer 104 can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or tantalic acid Piezoelectric materials with wurtzite crystal structure such as lithium (LiTaO3) and their combinations. When the piezoelectric layer 104 includes aluminum nitride (AlN), the piezoelectric layer 104 may further include rare earth metals, such as at least one of scandium (Sc), erbium (Er), yttrium (Y), and lanthanum (La). In addition, when the piezoelectric layer 104 includes aluminum nitride (AlN), the piezoelectric layer 104 may further include a transition metal, such as at least one of zirconium (Zr), titanium (Ti), manganese (Mn), and hafnium (Hf). kind. The piezoelectric layer 104 can be deposited and formed by any suitable method known to those skilled in the art, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition. Optionally, in this embodiment, the second electrode 105 and the first electrode 103 are made of metal molybdenum (Mo), and the piezoelectric layer 104 is made of aluminum nitride (AlN).

Referring to FIG. 4, step S03 is performed: forming a dielectric layer 102 to cover the piezoelectric laminate structure.

The dielectric layer 102 is formed by physical vapor deposition or chemical vapor deposition. The material of the dielectric layer 102 may be any suitable dielectric material, including but not limited to at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, and the like.

Referring to FIG. 5, step S05 is performed: the dielectric layer 102 is patterned to form a first cavity 110 a, and the first cavity 110 a penetrates the dielectric layer 102.

The dielectric layer 102 is etched by an etching process to form a first cavity 110a and expose the first electrode layer 103 at the bottom. The etching process may be a wet etching process or a dry etching process. Dry etching includes but is not limited to reactive ion etching (RIE), ion beam etching, and plasma etching. The depth and shape of the first cavity 110a depend on the depth and shape of the cavity required for the bulk acoustic wave resonator to be manufactured, that is, the depth of the first cavity 110a can be determined by the thickness of the dielectric layer 102 formed. The shape of the bottom surface of the first cavity 110a can be a rectangle or a polygon other than a rectangle, such as a pentagon, a hexagon, an octagon, etc., and can also be a circle or an ellipse.

Referring to FIG. 6, step S05 is performed: providing a carrier substrate, the carrier substrate includes a first semiconductor layer 100A and a first device layer 100B, the first surface of the carrier substrate is embedded with the first micro device 1000, and the second The side where a device layer 100B is located is the side where the first surface of the carrier substrate is located. For the material of the first semiconductor layer 100A, the material of the first device layer 100B, the type of the first micro-device 1000 and the structural relationship with the carrier substrate, refer to the related description of Embodiment 1, which will not be repeated here.

Referring to FIG. 7, step S06 is performed: bonding the carrier substrate to the dielectric layer 102, covering the first cavity 110a, and making the first surface face the first cavity 110a. For the material of the dielectric layer and the bonding method of the dielectric layer and the carrier substrate, refer to the related description of Embodiment 1.

Referring to FIG. 8, step S07 is performed: removing the temporary substrate. The method of removing the temporary substrate can be mechanical grinding.

9 and 10, in this embodiment, before forming the first electrical connection structure and connecting the first micro device, it further includes: forming a bonding layer 106 on the piezoelectric laminate structure, the bonding layer 106 encloses a second cavity 110b, which exposes the surface of the piezoelectric laminate structure, and the second cavity 110b is located above the first cavity 110a. A cover substrate is provided, the cover substrate includes a second semiconductor layer 200A and a second device layer 200B, a second micro device 2000 is embedded on the first surface of the cover substrate, and the second device layer 200B is located on the side The first surface of the cover substrate is located on the side. The cover substrate is disposed on the bonding layer 106 to cover the second cavity 110b, and the first surface of the cover substrate faces the second cavity 110b. For the material of the bonding layer 106, the material of the second semiconductor layer 200A, the material of the second device layer 200B, the type of the second micro device 2000 and the structure relationship with the cover substrate, please refer to the related description of Embodiment 1, which will not be repeated here. .

Referring to FIG. 11, step S08 is performed: forming a first electrical connection structure, and electrically connecting the first micro-device with an external signal. This embodiment also includes: forming a second electrical connection structure to electrically connect the second micro device with an external signal. The first electrical connection structure and the second electrical connection structure are the first conductive plug 1001 and the second conductive plug 2001 respectively. In this embodiment, forming the first conductive plug 1001 and the second conductive plug 2001 includes: forming a first through hole (not shown in the figure) penetrating the supporting substrate from the supporting substrate side and penetrating the through holes. The carrier substrate and the second through hole of the upper structure of the carrier substrate (the upper structure in this embodiment includes the dielectric layer 102, the piezoelectric laminate structure, the bonding layer 106, and part of the second device layer 200B) (not shown in the figure) (Shown), the first through hole exposes the first micro device 1000, the second through hole exposes the second micro device 2000, and the first through hole 1000 and the second through hole expose the second micro device 2000. A conductive material is formed in the hole 2000 to form the first conductive plug 1001 and the second conductive plug 2001. The first through hole and the second through hole may be formed by a dry etching process, and the conductive material may be formed in the first through hole and the second through hole by using an electroplating or electroless plating process.

In another embodiment, forming the first conductive plug 1001 and the second conductive plug 2001 includes: forming a third through hole penetrating the cover substrate from the cover substrate side, and penetrating the cover substrate and The fourth through hole of the structure under the cover substrate, the third through hole exposes the second micro device, the fourth through hole exposes the first micro device, and the third through hole And a conductive material is formed in the fourth through hole to form the second conductive plug and the first conductive plug.

The above two conductive plugs are both formed on the same side of the resonator (the side where the carrier substrate is located or the side where the cover substrate is located), and the reason for this arrangement is referred to the related description of Embodiment 1. The conductive plug is formed before the side of the carrier substrate, and it also includes the support of the cover substrate to reduce the thickness of the carrier substrate; the conductive plug is formed before the side of the cover substrate, and also includes the support of the carrier substrate to reduce the thickness. Cover the substrate.

In this embodiment, it further includes forming a first electrode lead-out part and a second electrode lead-out part, the first electrode lead-out part is connected to the first electrode 103, and the second electrode lead-out part is connected to the second electrode 105. The first electrode lead-out portion and the second electrode lead-out portion are located on the side of the carrier substrate. When the first conductive plug and the second conductive plug are located on the side of the cover substrate, the first electrode lead-out portion and the second electrode lead portion are also located on the side of the cover substrate in a preferred solution.

Wherein forming the first electrode lead-out part includes:

A through hole is formed through the lower layer structure of the first electrode 103 by an etching process, the through hole exposes the first electrode 103, and a first conductive interconnection layer is formed in the through hole by an electroplating process or a physical vapor deposition process 141. The first conductive interconnection layer 141 covers the inner surface of the through hole and a part of the surface of the carrier substrate 100 on the periphery of the through hole, and is connected to the first electrode 103; An insulating layer 160 is formed on the surface of a conductive interconnection layer 141 by a deposition process; first conductive bumps 142 are formed on the surface of the carrier substrate, and the first conductive bumps 142 are electrically connected to the first conductive interconnection layer 141. connect.

Forming the second electrode lead-out portion includes:

An etching process is used to form a through hole penetrating the lower layer structure of the first electrode 103, the through hole exposes the second electrode 105, and a second conductive interconnection layer 151 is formed in the through hole through a deposition process or an electroplating process, The second conductive interconnection layer 151 covers the inner surface of the through hole and a part of the surface of the carrier substrate on the periphery of the through hole, and is connected to the second electrode 105; The insulating layer 160 is formed by a deposition process; a second conductive bump 152 is formed on the surface of the carrier substrate 100, and the second conductive bump 152 is electrically connected to the second conductive interconnect layer 151.

It should be noted that the various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. . In particular, as for the method embodiment, since it is basically similar to the structural embodiment, the description is relatively simple, and for related parts, please refer to the part of the description of the method embodiment.

The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes or modifications made by a person of ordinary skill in the field of the present invention based on the above disclosure shall fall within the protection scope of the claims.

To

Claims

A thin film bulk acoustic wave resonator, characterized in that it comprises:

A carrier substrate, the carrier substrate including a first semiconductor layer and a first device layer;

A first micro device, the first micro device is embedded in the carrier substrate, and at least part of the first micro device is located in the first device layer;

A dielectric layer, bonded to the first device layer, the dielectric layer encloses a first cavity, and the first cavity exposes the surface of the carrier substrate;

A piezoelectric laminate structure covering the first cavity, the piezoelectric laminate structure including a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked from bottom to top;

The first electrical connection structure connects the first micro-device and electrically leads the first micro-device.
The thin film bulk acoustic resonator of claim 1, further comprising:

The bonding layer is disposed above the piezoelectric laminate structure, the bonding layer encloses a second cavity, and the second cavity exposes the surface of the piezoelectric laminate structure, and the second cavity is connected to The projection of the first cavity on the piezoelectric laminated structure has an overlapping part;

The cover substrate is arranged on the bonding layer and covers the second cavity.
The thin film bulk acoustic resonator of claim 2, wherein the cover substrate comprises a second semiconductor layer and a second device layer, the second device layer is close to the side where the second cavity is located; and include:

A second micro device, the second micro device is embedded in the cover substrate, and at least part of the second micro device is located in the second device layer;

The second electrical connection structure is connected to the second micro-device and electrically leads the second micro-device.
5. The thin film bulk acoustic resonator of claim 1, wherein the first electrical connection structure comprises:

The first conductive plug, the first conductive plug extends from the bottom surface of the carrier substrate to the first micro-device or; the first conductive plug extends from the top surface of the cover substrate to the The first micro-device.
The thin film bulk acoustic resonator of claim 3, wherein the second electrical connection structure comprises:

Second conductive plug, the second conductive plug extends from the bottom surface of the carrier substrate to the first micro-device or; the second conductive plug extends from the top surface of the cover substrate to the The second micro device.
3. The thin film bulk acoustic resonator of claim 3, further comprising a third electrical connection structure, the third electrical connection structure connecting the first micro-device and the second micro-device.
8. The thin film bulk acoustic resonator according to claim 3, wherein the first micro-device and/or the second micro-device comprises:

Diodes, triodes, MOS transistors, electrostatic discharge protection devices, resistors, capacitors or inductors.
The thin film bulk acoustic resonator of claim 1, wherein the material of the first device layer comprises silicon oxide, silicon nitride, silicon oxynitride, or silicon carbonitride.
The thin film bulk acoustic resonator of claim 1, wherein the material of the dielectric layer comprises silicon oxide, silicon nitride, silicon oxynitride, silicon carbonitride, or ethyl silicate.
5. The thin film bulk acoustic resonator of claim 1, wherein the dielectric layer and the first device layer are made of the same material, and the bonding method includes atomic bonding.
8. The thin film bulk acoustic resonator of claim 1, further comprising a bonding layer disposed between the dielectric layer and the carrier substrate.
11. The thin film bulk acoustic resonator of claim 11, wherein the bonding layer is made of silicon oxide, silicon nitride, polysilicon, ethyl silicate, or organic cured film.
The thin film bulk acoustic resonator according to claim 12, wherein the material of the dielectric layer and the bonding layer are the same.
The thin film bulk acoustic resonator of claim 1, further comprising:

A first groove, located inside the area enclosed by the first cavity, penetrates the first electrode, or penetrates the first electrode and the piezoelectric layer;

The second groove is located inside the area enclosed by the second cavity, is disposed opposite to the first groove in the lateral direction, and penetrates the second electrode, or penetrates the second electrode and the pressure Electric layer

The first groove and the second groove meet or are provided with a gap at two junctions of the projection of the carrier substrate.
The thin film bulk acoustic resonator of claim 1, wherein the area where the first electrode, the piezoelectric layer, and the second electrode overlap each other in a direction perpendicular to the carrier substrate is an effective resonance area, so The boundary of the effective resonance region is located in the area surrounded by the first cavity, and protrusions are provided at the boundary of the effective resonance region, and the protrusions are provided on the upper surface or the lower surface of the piezoelectric laminate structure; or ,

The protruding part is arranged on the upper surface of the piezoelectric laminated structure, and partly arranged on the lower surface of the piezoelectric laminated structure.
A method for manufacturing a thin film bulk acoustic wave resonator, which is characterized in that it comprises:

Provide temporary substrate;

Forming a piezoelectric laminate structure on the temporary substrate, the piezoelectric laminate structure including a second electrode, a piezoelectric layer, and a first electrode arranged in sequence from bottom to top;

Forming a dielectric layer to cover the piezoelectric laminate structure;

Patterning the dielectric layer to form a first cavity, and the first cavity penetrates the dielectric layer;

A carrier substrate is provided, the carrier substrate includes a first semiconductor layer and a first device layer, a first micro device is embedded in the carrier substrate, and at least part of the first micro device is located in the first device Layer

Bonding the first device layer of the carrier substrate to the dielectric layer to cover the first cavity;

Removing the temporary substrate;

A first electrical connection structure is formed, and the first micro-device is electrically drawn out.
16. The method of manufacturing a thin film bulk acoustic resonator according to claim 16, wherein after removing the temporary substrate and before forming the first electrical connection structure, the method further comprises:

A bonding layer is formed on the piezoelectric laminate structure, the bonding layer encloses a second cavity, the second cavity exposes the surface of the piezoelectric laminate structure, and the second cavity is located at the Above the first cavity;

A cover substrate is provided, the cover substrate is disposed on the bonding layer, covers the second cavity, and the first surface of the cover substrate faces the second cavity.
The method for manufacturing a thin film bulk acoustic resonator according to claim 17, wherein the first surface of the cover substrate is embedded with a second micro device, and the cover substrate is placed on the bonding layer. It also includes: forming a second electrical connection structure to electrically connect the second micro device with an external signal.
The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein the first electrical connection structure is a first conductive plug, and the second electrical connection structure is a second conductive plug to form a The first electrical connection structure and the second electrical connection structure include:

A first through hole that penetrates the carrier substrate and a second through hole that penetrates the carrier substrate and the upper structure of the carrier substrate are formed from the carrier substrate side, and the first through hole exposes the The first micro device, the second through hole exposes the second micro device, and a conductive material is formed in the first through hole and the second through hole to form the first conductive plug and the second through hole. Mentioned second conductive plug.
The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein the first electrical connection structure is a first conductive plug, and the second electrical connection structure is a second conductive plug to form a The first electrical connection structure and the second electrical connection structure include:

A third through hole penetrating the cover substrate and a fourth through hole penetrating through the cover substrate and the structure below the cover substrate are formed from the cover substrate side, and the third through hole exposes the The second micro device, the fourth through hole exposes the first micro device, and a conductive material is formed in the third through hole and the fourth through hole to form the second conductive plug and the Mentioned first conductive plug.
The method of manufacturing a thin-film bulk acoustic resonator according to claim 19 or 20, wherein the manufacturing method further comprises: forming a first electrode lead-out portion and a second electrode lead-out portion, and the first electrode lead-out portion is connected to In the first electrode, the second electrode lead-out part is connected to the second electrode, the first electrode lead-out part, the second electrode lead-out part, the second conductive plug, the first All the lead-out ends of the conductive plugs are located on the side where the cover substrate is located or the side where the carrier substrate is located.
16. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein after forming the first cavity and before bonding the carrier substrate, the method further comprises:

Patterning the first electrode, or the first electrode and the piezoelectric layer, to form a partial boundary of the effective resonance region;

After removing the temporary substrate, it also includes:

The second electrode, or the second electrode and the piezoelectric layer are patterned to form another part of the boundary of the effective resonance region, and the boundary of the effective resonance region is located between the first cavity and the first cavity. The two cavities are projected and overlapped in the direction of the piezoelectric layer.
The method for manufacturing a thin film bulk acoustic resonator according to claim 18, wherein the first micro-device and/or the second micro-device comprises:

Diodes, triodes, MOS transistors, electrostatic discharge protection devices, resistors, capacitors or inductors.
24. The method of manufacturing a thin film bulk acoustic resonator according to claim 16, wherein the material of the first device layer includes silicon oxide, silicon nitride, silicon oxynitride, and silicon carbon nitride.
The method for manufacturing a thin film bulk acoustic resonator according to claim 24, wherein the material of the dielectric layer is the same as the material of the first device layer, and the carrier substrate is bonded to the dielectric layer Including: direct bonding through atomic bonds.
16. The method for manufacturing a thin film bulk acoustic resonator according to claim 16, wherein bonding the carrier substrate on the dielectric layer comprises:

A bonding layer is formed on the surface of the dielectric layer, and the dielectric layer and the carrier substrate are bonded through the bonding layer, and the dielectric layer and the bonding layer are made of the same material.