CN112039484A - A thin-film bulk acoustic wave resonator and its manufacturing method - Google Patents

Abstract

The present invention provides a thin-film bulk acoustic resonator and a method for manufacturing the same, wherein the thin-film bulk acoustic resonator includes: a carrier substrate, the carrier substrate includes a first semiconductor layer and a first device layer; a first micro-device, the 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 is bonded on the first device layer, and the dielectric layer is The layers enclose a first cavity, and the first cavity exposes the surface of the carrier substrate; the piezoelectric laminated structure covers the first cavity, and the piezoelectric laminated structure includes sequentially from bottom to top The laminated first electrode, the piezoelectric layer and the second electrode; the first cavity is formed before the piezoelectric laminated structure, and is located below the piezoelectric laminated structure; the first electrical connection structure is connected to the The first micro device is electrically led out. The present invention can improve the integration degree of the resonator.

Description

A thin-film bulk acoustic wave resonator and its manufacturing method

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, the terminal equipment needs to be able to transmit data using different carrier frequency spectrums. RF systems also impose stringent performance requirements. The radio frequency filter is an important part of the radio frequency system, which 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, a 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. 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 and is reflected back, and then reflected back and forth inside the film to form an oscillation. Standing wave oscillations are formed when a sound wave propagates in a piezoelectric film layer that is exactly an odd multiple of a half-wavelength.

However, the traditionally fabricated cavity-type thin-film BAW resonator cannot integrate micro-devices in the substrate under the cavity due to the limitation of the cavity formation process, and can only connect the resonator with external devices to realize related functions, resulting in the device Due to the large volume and long lead wires, the integration of the resonator is not high, which cannot meet the requirements of miniaturization of the device.

SUMMARY OF THE INVENTION

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-mentioned technical problems, the present invention provides a thin-film bulk acoustic resonator, comprising:

a carrier substrate, the carrier substrate includes 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 a portion of the first micro-device is located in the first device layer;

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

The piezoelectric laminated structure covers the first cavity, and the piezoelectric laminated 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 Before the piezoelectric stack structure, it is located below the piezoelectric stack 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 thin-film bulk acoustic wave resonator, comprising:

provision of temporary substrates;

forming a piezoelectric stack structure on the temporary substrate, the piezoelectric stack structure comprising a second electrode, a piezoelectric layer, and a first electrode sequentially arranged from bottom to top;

forming a dielectric layer to cover the piezoelectric laminated structure;

patterning the dielectric layer to form a first cavity, the first cavity passing through 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 a first surface of the carrier substrate, and the side where the first device layer is located is the side of the carrier substrate. 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 to electrically connect the first micro device with an external signal.

The beneficial effects of the present invention are:

Before bonding the carrier substrate, the first micro device is pre-formed in the carrier substrate, which is separated from the fabrication of the resonator and shortens the process time. The micro-devices can be fabricated independently without being fabricated in the resonator manufacturing process, so that the resonator structure can be prevented from being subjected to the process environment when the micro-devices are fabricated, and the stability of the resonator can be improved. Since the structure is to bond the carrier substrate on the dielectric layer by means of bonding, it is possible to form the first micro device in the carrier substrate in advance.

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

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

Further, 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 bulge is arranged along the boundary of the effective resonant area, so that the acoustic impedance of the inside of the effective resonant area and the area where the bulge is located are mismatched, the lateral leakage of the acoustic wave is effectively prevented, and the quality factor of the resonator is improved;

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 penetrate the first electrode and the second electrode respectively, and the piezoelectric layer keeps 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 drawings

The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of the exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which the same reference numerals generally refer to the same parts .

FIG. 1 shows a schematic structural diagram of a thin film bulk acoustic wave resonator of Example 1. FIG.

2 to 11 are schematic structural diagrams corresponding to different steps of a method for manufacturing a thin film bulk acoustic resonator according to Embodiment 2.

Description of reference numbers:

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-insulation layer; 200A-second semiconductor layer; 200B-second device layer; 2000-second micro-device; 2001-second conductive plug; 40-bump; 300-temporary substrate.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and accompanying drawings. However, it should be noted that the concept of the technical solution of the present invention can be implemented in various forms, and is not limited to the specific implementation described here. example. The accompanying drawings are all in a very simplified form and use inaccurate scales, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.

It will 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 Layers may be on, 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 present. Floor. It will 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. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatial relational terms such as "under", "below", "below", "under", "above", "above", etc., in It may be used herein for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below" and "under" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the/the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "compose" and/or "include", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence 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 the associated listed items.

If a method herein includes a series of steps, the order of the steps presented herein is not necessarily the only order in which the steps may be performed, and some of the 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 the components in other drawings, although these components can be easily identified in all the drawings, in order to make the description of the drawings clearer, this specification will not refer to all the same components. Numbers are attached to each figure.

Example 1

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

a carrier substrate, the carrier substrate 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 stack structure covers the first cavity 110a, the piezoelectric stack structure includes a first electrode 103, a piezoelectric layer 104 and a second electrode 105 stacked in sequence from bottom to top, the first cavity 110a is formed before the piezoelectric stack structure, and is located below the piezoelectric stack structure;

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

It should be noted that, the first cavity 110a is formed before the piezoelectric stack structure, and is located under the piezoelectric stack structure as follows: In the prior art, the resonator is manufactured as follows: A cavity is formed by etching on the substrate, 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 at the bottom. above the cavity. After the piezoelectric stack structure is formed, a capping layer may also be formed on the upper surface of the piezoelectric stack, and the cavity between the capping layer and the piezoelectric stack structure is an upper cavity. The first cavity of the present invention corresponds to the lower cavity. The carrier substrate of this embodiment is bonded on 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 fabrication and patterning of the bonding layer, the fabrication/grinding of the capping layer, or the fabrication of the second electrical connection structure. Since the structure is to bond the carrier substrate on the dielectric layer by means of bonding, it is possible to form the first micro device in the carrier substrate in advance. The lower cavity is formed by the method of the sacrificial layer, and the micro device cannot be formed at the bottom of the lower cavity. Before bonding the carrier substrate, the first micro device is pre-formed in the carrier substrate to shorten the process time. The micro-devices can be fabricated independently without being fabricated in the resonator manufacturing process, so that the resonator structure can be prevented from being subjected to the process environment when the micro-devices are fabricated, and the stability of the resonator can be 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 at least partially formed in the first device layer 100B. The first micro-device 1000 includes: diodes, triodes, MOS transistors, electrostatic discharge protection devices, resistors, capacitors or inductors. 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, the source and drain stages of the first micro-device 1000 are may be 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, etc. Materials of the first device layer 100B include 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 for direct bonding. 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 surfaces of the two, and the material of the bonding layer includes: silicon oxide, silicon nitride, polysilicon, ethyl silicate or organic cured film. In this embodiment, the first device layer 100B and the dielectric layer are both silicon oxides, which are bonded by atomic bonds. 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 known from the materials of the dielectric layer and the bonding layer that the materials of the two can be the same or different.

In this embodiment, the first cavity 110a is a closed cavity, and the first cavity 110a can 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 bottom surface 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 laminated structure is disposed above the first cavity 110a, and the piezoelectric laminated structure includes a first electrode 103, a piezoelectric layer 104 and a second electrode 105 in sequence 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 overlapping regions in the direction perpendicular to the carrier substrate 100 as an effective resonance region, and the boundary of the effective resonance region is located at the within the area surrounded by the first cavity 110a. The shape of the effective resonance region is an irregular polygon, such as a pentagon or a 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 as the piezoelectric layer 104 is a complete film layer without being 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. Without etching the piezoelectric layer, the piezoelectric laminated structure can be guaranteed to have a certain thickness, so that the resonator has a certain structural strength. Improve the yield of making resonators.

In one embodiment, an etch stop layer is further disposed between the dielectric layer 102 and the first electrode 103, and its material includes but 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 fabricated thin-film bulk acoustic wave resonator; In the process of forming the first cavity 110a of the layer 102, over-etching is prevented, and the surface of the first electrode 103 located thereunder is protected from damage, thereby improving the performance and reliability of the device.

In this embodiment, a bonding layer 106 is included on top of the piezoelectric stack structure, the bonding layer 106 encloses a second cavity 110b, and the second cavity 110b exposes the surface of the piezoelectric stack structure, so The second cavity 110b is located above the first cavity 110a. It also includes a capping 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 near the second cavity 110b.

In this embodiment, the capping substrate has a double-layer structure, including 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, please refer to the 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 optional material of the second device layer 200B, refer to the material type of the first device layer 100B, which will not be repeated here. The bonding layer 106 may use conventional bonding materials, such as silicon oxide, silicon nitride, silicon oxynitride, ethyl silicate, etc., or may be adhesives such as light-curing materials or thermal-curing materials, such as die attach film. Film, DAF) or dry film (Dry Film), 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 have an integral structure. The second cavity 110b is formed by forming a space in the film layer (for 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 the first conductive plug 1001 , and the second electrical connection structure is the 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, a first conductive plug may extend from the top surface of the capping substrate to the first micro-device. A second conductive plug also extends from the top surface of the capping 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 the opposite side of the conductive plug needs to be supported with a certain strength when making the conductive plug. When making conductive plugs, the side of the conductive plugs (the carrier substrate or the cover substrate) needs to be thinned to a thickness of about 100 microns, and the opposite side of the conductive plugs (the carrier substrate or the cover substrate) is not Do thinning treatment, the thickness is about several hundred microns, which provides 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 one embodiment, a third electrical connection structure, such as a third conductive plug, may also be included to electrically connect the first micro-device and the second micro-device.

In this embodiment, a first electrode lead-out portion and a second electrode lead-out portion are further included. The first electrode lead-out portion is used for introducing electrical signals into the first electrode 103 of the effective resonance region, and the second electrode lead-out portion is used for introducing electrical signals into the first electrode 103 of the effective resonance region. The second electrode 105 of the effective resonance region. After the first electrode 103 and the second electrode 105 are energized, a voltage difference is generated between the upper and lower surfaces of the piezoelectric layer 104 to form a standing wave oscillation. The conductive interconnect structure 120 is used to short the first electrode and the second electrode outside the effective resonance region. It can be seen from the figure that the area where the piezoelectric layer, the first electrode and the second electrode overlap each other in the direction perpendicular to the piezoelectric layer is also included outside the effective resonance area. When the first electrode and the second electrode are energized, a voltage difference can also be generated above and below the surface of the piezoelectric layer outside the effective resonance area, and standing wave oscillation is also generated. However, the standing wave oscillation outside the effective resonance area is undesirable. For example, the first electrode and the second electrode outside the effective resonance area are short-circuited, so that the upper and lower voltages of the piezoelectric layer outside the effective resonance area are consistent, and standing wave oscillation cannot be generated outside the effective resonance area, which improves the Q value of the resonator. The specific structures of the first electrode lead-out portion, the second electrode lead-out portion and the conductive interconnection structure 120 are as follows:

The first electrode lead-out part includes:

A first through hole 140, the first through hole 140 penetrates the lower layer structure of the first electrode 103 outside the effective resonance area, 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 around the first through hole 140 are connected to the first electrode 103 ; the insulating layer 160 covers the first conductive interconnect layer 141 and the first electrode 103 . The surface of the carrier substrate 100 ; the conductive bumps 142 are disposed on the surface of the carrier substrate 100 and electrically connected to the first conductive interconnect layer 141 .

The second electrode lead-out part includes:

The second through hole 150, the second through hole 150 penetrates the lower layer 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 second through hole 150 and part of the surface of the carrier substrate 100 around the second through hole 150 are connected to the first electrode 103 ; the insulating layer 160 covers the second conductive interconnection layer 151 and The surface of the carrier substrate 100 ; the second conductive bumps 152 are disposed on the surface of the carrier substrate 100 and electrically connected to the second conductive interconnect 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 layered structure. The upper surface of the stacked structure is partially disposed on the lower surface of the piezoelectric stacked structure.

In this embodiment, the protrusions 40 are all 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 protrusions 40 is an effective resonance area, and the outside of the protrusions 40 is an ineffective resonance area. The first electrode 103 , the piezoelectric layer 104 and the second electrode 105 in the effective resonance region 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 partially disposed on the upper surface of the piezoelectric laminated structure, and partially disposed on the lower surface of the piezoelectric laminated structure.

In this embodiment, the projection of the protrusions 40 on the carrier substrate 100 forms a closed annular shape, such as a closed irregular polygon, circle or ellipse. The bulge 40 has its internal effective resonance area mismatched with the acoustic impedance of the area where the bulge 40 is located, which can effectively prevent lateral leakage of sound waves and improve the quality factor of the resonator. In other embodiments, the projection of the protrusions 40 on the carrier substrate 100 may not be a completely closed figure. It should be understood that when the projection of the protrusions 40 on the carrier substrate 100 is a closed figure, it is more beneficial to prevent the lateral leakage of sound waves.

The material of the protrusion 40 can be a conductive material or a dielectric material. When the material of the protrusion 40 is a conductive material, it can be the same as the material of the first electrode 103 or the second electrode 105. When the material of the protrusion 40 is The dielectric material 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 trench 130a and a second trench 130b, and the first trench 130a is located on the lower surface of the piezoelectric laminate structure and on the side where the first cavity 110a is located. , runs through the first electrode 103 and surrounds the outer periphery of the area where the protrusion 40 is located. The second groove 130b is located on the upper surface of the piezoelectric stack, penetrates through the second electrode 105, and surrounds the outer periphery of the area where the protrusion 40 is located. The two ends of the first trench 130a and the two ends of the second trench 130b are disposed opposite to each other, so that the projections of the first trench 130a and the second trench 130b on the carrier substrate 100 are opposite to each other. 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, all the 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 figures, which are consistent with the projections of the projections 40 on the carrier substrate 100 , and are located at the outer periphery of the projections formed by the projections 40 . .

It should be understood that the protrusions 40 are annular (when the protrusions 40 are all located on the lower surface or the upper surface of the piezoelectric laminate structure, the protrusions 40 form an annular shape; when the protrusions 40 are located on both surfaces of the piezoelectric laminate structure, The projections of the two parts together form a whole ring). When the protrusions 40 are all located on the upper surface or the 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 remaining part of the outer circumference of the protrusion 40 (this When the second groove 130b surrounds the outer circumference of the protrusion 40, it means that the second groove 130b surrounds the outer circumference of the surface of the piezoelectric laminate structure in the region of the protrusion 40, and does not directly surround the outer circumference of the protrusion 40). When the protrusions 40 are 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 can surround the first groove 130a located under 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 bump 40 mismatches the acoustic impedance of the region inside the bump with the acoustic impedance of the region where the bump is located, defining the boundary of the effective resonant region of the resonator. The first trench 130a and the second trench 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 overlapping each other in the thickness direction), which further defines the boundary of the effective resonance region of the resonator. The protrusion 40 makes the acoustic impedance mismatch through the addition of the mass, and the first groove 130a and the second groove 130b make the acoustic impedance mismatch by contacting the electrode end face with the air, both of which play a role in preventing the leakage of the shear wave, Improves the Q of the resonator. Of course, in other embodiments, only the first trench 130a or the second trench 130b may be provided alone. Since the first electrode 103 and the second electrode 105 need to introduce electrical signals, the first trench 130a or the second trench 130b The 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 can be formed into a nearly closed ring, and the non-closed area is used for introducing electrical signals. This arrangement simplifies the process flow and reduces the cost of the resonator.

In this embodiment, the conductive interconnect structure 120 is further included. The conductive interconnect structure 120 includes two parts. It is electrically connected to the first electrode lead-out portion. The other part of the conductive interconnect structure 120 is disposed in the outer region of the first trench 130a, connects the first electrode 103 and the second electrode 105, and is electrically connected to the lead-out portion of the second electrode through the first electrode 103. The two parts of the conductive interconnect structure 120 are provided with an area covering part of the surface of the second electrode 105 , this area 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 area, and is electrically connected to the second electrode of the effective resonance area through the conductive interconnect structure 120 . It can be seen that the first electrode lead-out part and the second electrode lead-out part are the same in structure, but the positions are different. An electrode is powered, and the first electrode lead-out portion is electrically connected to the second electrode outside the effective resonance region through the first electrode outside the effective resonance region and the conductive interconnect structure 120, and is not connected to the second electrode inside the effective resonance region. Similarly, 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, so as to supply power to the second electrode inside the effective resonance area.

Example 2

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

S01: Provide a temporary substrate;

S02: forming a piezoelectric stack structure on the temporary substrate, where the piezoelectric stack structure includes a second electrode, a piezoelectric layer, and a first electrode sequentially arranged from bottom to top;

S03: forming a dielectric layer to cover the piezoelectric laminated 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, a first micro-device is embedded in a first surface of the carrier substrate, 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 the SON is not used to limit the sequence of steps. FIGS. 2 to 11 are schematic structural diagrams of 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 for detailed description of each step.

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 following mentioned materials: 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, and may also be ceramic substrates such as alumina, quartz or glass substrates, and the like.

Referring to FIG. 3 , step S02 is performed: forming a piezoelectric stack structure on the temporary substrate 300 , and the piezoelectric stack structure includes a second electrode 105 , a piezoelectric layer 104 , and a first electrode sequentially arranged from bottom to top 103.

The material of the second electrode 105 and the first electrode 103 can be any suitable conductive material or semiconductor material known to those skilled in the art, wherein the conductive material can be a metal material with conductive properties, such as 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 a laminate of the above metals, and 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 such as magnetron sputtering, evaporation, or chemical vapor deposition. The piezoelectric layer 104 can be made of aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz), potassium niobate (KNbO3) or tantalic acid Piezoelectric materials having a wurtzite crystal structure, such as lithium (LiTaO3), and combinations thereof. When the piezoelectric layer 104 includes aluminum nitride (AlN), the piezoelectric layer 104 may further include a rare earth metal 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 may be deposited using 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 stack 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 other materials.

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 first cavity 110a is formed by etching the dielectric layer 102 through an etching process, and the first electrode layer 103 at the bottom is exposed. The etching process may be wet etching or dry etching, and 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 fabricated, that is, the depth of the first cavity 110a can be determined by forming the thickness of the dielectric layer 102 . The shape of the bottom surface of the first cavity 110a may be a rectangle or a polygon other than a rectangle, such as a pentagon, a hexagon, an octagon, etc., or a circle or an ellipse.

Referring to FIG. 6 , step S05 is performed: a carrier substrate is provided, the carrier substrate includes a first semiconductor layer 100A and a first device layer 100B, a first surface of the carrier substrate is embedded with a first micro-device 1000 , and the first micro-device 1000 is embedded in the first surface of the carrier substrate. 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 relevant description of Embodiment 1, and 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 110 a , and making the first surface face the first cavity 110 a . For the material of the dielectric layer and the bonding method between the dielectric layer and the carrier substrate, refer to the relevant description in Embodiment 1.

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

Referring to FIG. 9 and FIG. 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 stack structure, the bonding layer 106 encloses a second cavity 110b, the second cavity 110b 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 in the first surface of the cover substrate, and the side where the second device layer 200B is located is the side where the first surface of the cover substrate is located. The capping substrate is disposed on the bonding layer 106 to cover the second cavity 110b, and the first surface of the capping substrate faces the second cavity 110b. 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 structural relationship with the capping substrate refer to the relevant description of Embodiment 1, and will not be repeated here. .

Referring to FIG. 11 , step S08 is performed: forming a first electrical connection structure to electrically connect the first micro device with an external signal. This embodiment further 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 carrier substrate from the side of the carrier substrate and penetrating the carrier substrate. The second through hole (not shown in the figure) of the carrier substrate and the upper structure of the carrier substrate (in this embodiment, the upper structure includes the dielectric layer 102, the piezoelectric stack structure, the bonding layer 106 and part of the second device layer 200B) 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. 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 in the first through hole and the second through hole may be formed by 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 capping substrate from a side of the capping substrate and penetrating the capping 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 exposes the first micro device and forming a conductive material in the fourth through hole to form the second conductive plug and the first conductive plug.

The above two conductive plugs are 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). The conductive plug is formed before the side where the carrier substrate is located, and further includes using the cover substrate as a support to reduce the thickness of the carrier substrate; the conductive plug is formed before the side where the cover substrate is located, and further includes using the carrier substrate as a support to reduce the thickness Cover the substrate.

In this embodiment, it also includes forming a first electrode lead-out portion and a second electrode lead-out portion, the first electrode lead-out portion is connected to the first electrode 103 , and the second electrode lead-out portion 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 where the carrier substrate is located. When the first conductive plug and the second conductive plug are located on the side where the cover substrate is located, the first electrode lead-out portion and the second electrode lead-out portion are preferably also located on the side where the cover substrate is located.

Wherein forming the first electrode lead-out portion includes:

A through hole is formed through the underlying structure of the first electrode 103 through an etching process, the through hole exposes the first electrode 103, and a first conductive interconnect layer is formed in the through hole through an electroplating process or a physical vapor deposition process 141, the first conductive interconnect layer 141 covers the inner surface of the through hole and a part of the surface of the carrier substrate 100 around the through hole, and is connected to the first electrode 103; An insulating layer 160 is formed on the surface of a conductive interconnect 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 interconnect layer 141 connect.

Forming the second electrode lead-out portion includes:

A through hole is formed through the underlying structure of the first electrode 103 through an etching process, the through hole exposes the second electrode 105, a second conductive interconnect layer 151 is formed in the through hole through a deposition process or an electroplating process, The second conductive interconnect layer 151 covers the inner surface of the through hole and part of the surface of the carrier substrate around the through hole, and is connected to the second electrode 105; A deposition process forms an insulating layer 160 ; 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 each embodiment in this specification is described in a related manner, and the same and similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. . In particular, for the method embodiments, since they are basically similar to the structural embodiments, the description is relatively simple, and reference may be made to some descriptions of the method embodiments for related parts.

The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes and modifications made by those of ordinary skill in the field of the present invention based on the above disclosure all belong to the protection scope of the claims.

Claims (26)

1. A thin film bulk acoustic resonator, comprising:

the device comprises a bearing substrate, a first substrate and a second substrate, wherein the bearing substrate comprises a first semiconductor layer and a first device layer;

a first micro device embedded in the carrier substrate, and at least a portion of the first micro device being located in the first device layer;

the dielectric layer is bonded on the first device layer, the dielectric layer surrounds a first cavity, and the surface of the bearing substrate is exposed out of the first cavity;

the piezoelectric laminated structure covers the first cavity and comprises a first electrode, a piezoelectric layer and a second electrode which are sequentially laminated from bottom to top;

and the first electric connection structure is connected with the first micro device and electrically leads out the first micro device.

2. The thin film bulk acoustic resonator of claim 1, further comprising:

the junction layer is arranged above the piezoelectric laminated structure, a second cavity is surrounded by the junction layer, the surface of the piezoelectric laminated structure is exposed out of the second cavity, and the projection of the second cavity and the projection of the first cavity on the piezoelectric laminated structure are overlapped;

and the sealing cover substrate is arranged on the bonding layer and covers the second cavity.

3. The thin film bulk acoustic resonator of claim 2, wherein the capping substrate comprises a second semiconductor layer and a second device layer, the second device layer being adjacent to a side of the second cavity; further comprising:

a second micro device embedded in the capping substrate, at least a portion of the second micro device being located in the second device layer;

and the second electric connection structure is connected with the second micro device and electrically leads out the second micro device.

4. The thin film bulk acoustic resonator of claim 1, wherein the first electrical connection structure comprises:

a first conductive plug extending from a bottom surface of the carrier substrate to the first micro device or; the first conductive plug extends from the top surface of the capping substrate to the first micro device.

5. The film bulk acoustic resonator of claim 3, wherein the second electrical connection structure comprises:

a second conductive plug extending from a bottom surface of the carrier substrate to the first micro device or; the second conductive plug extends from the top surface of the capping substrate to the second micro device.

6. The thin film bulk acoustic resonator of claim 3, further comprising a third electrical connection structure connecting the first micro device and the second micro device.

7. The thin film bulk acoustic resonator of claim 3, wherein the first micro device and/or the second micro device comprises:

a diode, a triode, a MOS transistor, an electrostatic discharge protection device, a resistor, a capacitor or an inductor.

8. 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.

9. The 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.

10. The 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 manner comprises: the atoms are bonded.

11. The film bulk acoustic resonator of claim 1, further comprising a bonding layer disposed between the dielectric layer and the carrier substrate.

12. The film bulk acoustic resonator of claim 11, wherein the bonding layer comprises a material comprising: silicon oxide, silicon nitride, polysilicon, ethyl silicate, or an organic cured film.

13. The film bulk acoustic resonator of claim 12, wherein the dielectric layer and the bonding layer are of the same material.

14. The thin film bulk acoustic resonator of claim 1, further comprising:

a first trench located inside an area surrounded by the first cavity, penetrating the first electrode, or penetrating the first electrode and the piezoelectric layer;

the second groove is positioned in an area enclosed by the second cavity, is arranged opposite to the first groove in the transverse direction, and penetrates through the second electrode or penetrates through the second electrode and the piezoelectric layer;

the first groove and the second groove are connected or provided with a gap at two junctions of the projection of the bearing substrate.

15. The film bulk acoustic resonator according to claim 1, wherein an area where the first electrode, the piezoelectric layer, and the second electrode overlap with each other in a direction perpendicular to the carrier substrate is an effective resonance area, a boundary of the effective resonance area is located in an area surrounded by the first cavity, a protrusion is provided at the boundary of the effective resonance area, and the protrusion is provided on an upper surface or a lower surface of the piezoelectric laminated structure; or the like, or, alternatively,

the protruding part is arranged on the upper surface of the piezoelectric laminated structure, and the part is arranged on the lower surface of the piezoelectric laminated structure.

16. A method of manufacturing a film bulk acoustic resonator, comprising:

providing a temporary substrate;

forming a piezoelectric laminated structure on the temporary substrate, wherein the piezoelectric laminated structure comprises a second electrode, a piezoelectric layer and a first electrode which are sequentially arranged from bottom to top;

forming a dielectric layer to cover the piezoelectric laminated structure;

patterning the dielectric layer to form a first cavity, wherein the first cavity penetrates through the dielectric layer;

providing a carrier substrate, wherein the carrier substrate comprises 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 positioned in the first device layer;

bonding the first device layer of the bearing substrate to the dielectric layer and covering the first cavity;

removing the temporary substrate;

and forming a first electric connection structure to lead out the first micro device electrically.

17. The method of manufacturing a thin film bulk acoustic resonator according to claim 16, further comprising, after removing the temporary substrate and before forming the first electrical connection structure:

forming a bonding layer on the piezoelectric laminated structure, wherein the bonding layer surrounds a second cavity, the second cavity exposes the surface of the piezoelectric laminated structure, and the second cavity is positioned above the first cavity;

and providing a cover substrate, arranging the cover substrate on the junction layer, covering the second cavity, and enabling the first surface of the cover substrate to face the second cavity.

18. The method of manufacturing a thin film bulk acoustic resonator according to claim 17, wherein the step of embedding a second micro device in the first surface of the cover substrate and the step of disposing the cover substrate on the bonding layer further comprises: and forming a second electric connection structure for electrically connecting the second micro device with an external signal.

19. The method of manufacturing a thin film bulk acoustic resonator according to claim 18, wherein the first electrical connection structure is a first conductive plug, the second electrical connection structure is a second conductive plug, and forming the first electrical connection structure and the second electrical connection structure includes:

forming a first through hole penetrating through the bearing substrate and a second through hole penetrating through the bearing substrate and the bearing substrate upper structure from the bearing substrate side, wherein the first through hole exposes 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 conductive plug.

20. The method of manufacturing a thin film bulk acoustic resonator according to claim 18, wherein the first electrical connection structure is a first conductive plug, the second electrical connection structure is a second conductive plug, and forming the first electrical connection structure and the second electrical connection structure includes:

and forming a third through hole penetrating through the cover substrate and a fourth through hole penetrating through the cover substrate and the structure below the cover substrate from the side of the cover substrate, wherein the third through hole exposes 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 first conductive plug.

21. The method of manufacturing a thin film bulk acoustic resonator according to claim 19 or 20, further comprising: and forming a first electrode leading-out part and a second electrode leading-out part, wherein the first electrode leading-out part is connected with the first electrode, the second electrode leading-out part is connected with the second electrode, and leading-out ends of the first electrode leading-out part, the second conductive plug and the first conductive plug are all positioned on the side where the cover substrate is positioned or the side where the bearing substrate is positioned.

22. The method of manufacturing a thin film bulk acoustic resonator according to claim 16, further comprising, after forming the first cavity and before bonding the carrier substrate:

patterning the first electrode, or the first electrode and the piezoelectric layer, to form part of the boundary of the effective resonance region;

after removing the temporary substrate, the method further comprises:

patterning the second electrode, or the second electrode and the piezoelectric layer, to form another part of a boundary of an effective resonance area, where the boundary of the effective resonance area is located in an area where projections of the first cavity and the second cavity overlap in the direction of the piezoelectric layer.

23. The method of manufacturing a thin film bulk acoustic resonator of claim 18, wherein the first micro device and/or the second micro device comprises:

a diode, a triode, a MOS transistor, an electrostatic discharge protection device, a resistor, a capacitor or an inductor.

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, silicon carbonitride.

25. The method of manufacturing a thin film bulk acoustic resonator according to claim 24, wherein a material of the dielectric layer is the same as a material of the first device layer, and bonding the carrier substrate on the dielectric layer comprises: bonded directly through an atomic bond.

26. The method of manufacturing a thin film bulk acoustic resonator according to claim 16, wherein bonding the carrier substrate on the dielectric layer comprises:

and forming a bonding layer on the surface of the dielectric layer, and bonding the dielectric layer and the bearing substrate through the bonding layer, wherein the dielectric layer and the bonding layer are made of the same material.

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