A filter packaging method based on a glass substrate and its packaging structure

Abstract

The present application provides a filter packaging method and a packaging structure based on a glass substrate, including: providing a first glass substrate, and disposing at least one second glass substrate on one side surface of the first glass substrate along its thickness direction. A through hole is formed in the middle of the second glass substrate, and a preset circuit is disposed on the second glass substrate; providing at least one filter chip, correspondingly disposing one filter chip on one second glass substrate, making the functional area correspond to the position of the through hole, and making the electrical signal connection port electrically connected to the preset circuit; providing a plastic encapsulant, performing plastic encapsulation on the second glass substrate, and forming a plastic encapsulation layer after curing. The plastic encapsulation layer only wraps the filter chip therein, and exposes the pad area of the preset circuit; providing metal bumps, and electrically connecting the metal bumps to the pad area of the preset circuit; cutting the first glass substrate to form single discrete filter packaging structures. The present application adopts a double-layer glass substrate to form a cavity structure, improving reliability.

Description

Technical Field

[0001] The present application relates to the field of filter packaging, and particularly relates to a filter packaging method based on a glass substrate and its packaging structure. Background Art

[0002] With the rapid development of the wireless communication industry, higher requirements are put forward for filters. Film Bulk Acoustic Resonator (FBAR for short) has the characteristics of small size, low cost, high quality factor (Q, the main characteristic of a filter), strong power tolerance, high frequency and compatibility with IC technology, and is widely used in the field of wireless communication.

[0003] The existing FBAR filter packaging structure usually bonds a substrate to the functional surface of the filter chip, and then performs a TSV interconnection structure on the substrate to electrically lead out the signal pads of the filter chip to the substrate. Since silicon is a good conductor of heat, the thermal conductivity can be significantly improved, thus extending the life of the device. Therefore, the substrate generally uses a silicon substrate. However, in this packaging structure, using a silicon substrate as the substrate still has defects such as poor reliability and insufficient electrical performance, and this packaging structure requires drilling, with a complex process.

[0004] Therefore, there is an urgent need for improvement in the prior art. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a filter packaging method based on a glass substrate and its packaging structure, to solve the problems of poor reliability of the packaging substrate and insufficient electrical performance in the existing filter chip packaging process, which can greatly improve the signal transmission rate of the packaging structure, reduce signal loss at the same time, and improve reliability.

[0006] The embodiments of the present application provide a filter packaging method based on a glass substrate, including the following steps:

[0007] A. Provide a first glass substrate, and dispose at least one second glass substrate on one side of the first glass substrate along its thickness direction. A through hole is formed in the middle of the second glass substrate, and a preset circuit is provided on the second glass substrate;

[0008] B. Provide at least one filter chip. The filter chip includes a chip substrate, a functional area formed in the middle of the front surface of the chip substrate, and a plurality of electrical signal connection ports located around the functional area. Correspondingly dispose one filter chip on one second glass substrate, so that the functional area corresponds to the position of the through hole, and electrically connect the electrical signal connection ports to the preset circuit;

[0009] C. Provide a molding compound, perform molding on the second glass substrate, and form a molding layer after curing. The molding layer only wraps the filter chip and exposes the pad area of the preset circuit;

[0010] D. Provide metal bumps and electrically connect the metal bumps to the pad area of the preset circuit;

[0011] E. Cut the first glass substrate to form single discrete filter package structures.

[0012] Preferably, in the filter package method based on a glass substrate according to an embodiment of the present application, before the step A, the following steps are included:

[0013] S1. Provide at least one second glass substrate, etch through holes in the middle of the second glass substrate, and etch grooves with a preset circuit shape on the front surface of the second glass substrate;

[0014] S2. Provide nano-conductive metal particles and fill the nano-conductive metal particles into the grooves;

[0015] S3. Irradiate the nano-conductive metal particles with a laser to sinter the nano-conductive metal particles to form the preset circuit.

[0016] Preferably, in the filter package method based on a glass substrate according to an embodiment of the present application, between the step S1 and the step S2, the following steps are further included: Immerse the side surface of the second glass substrate etched with grooves having a preset circuit shape in a silane coupling agent solution and then dry.

[0017] Preferably, in the filter package method based on a glass substrate according to an embodiment of the present application, between the step S1 and the step S2, the following steps are further included: Sputter a metal seed layer on the inner wall of the grooves.

[0018] Preferably, in the filter package method based on a glass substrate according to an embodiment of the present application, in the step S2, the nano-conductive metal particles are one or a combination of nano-conductive metal particles, nano-silver particles, nano-gold particles, or nano-tin particles.

[0019] Preferably, in the filter package method based on a glass substrate according to an embodiment of the present application, in the step S2, the following steps are included:

[0020] S21. Provide nano-conductive metal particles and a solvent to make a nano-conductive metal paste;

[0021] S22. Fill the nano-conductive metal paste into the grooves;

[0022] S23. Dry and semi-cure the nano-conductive metal paste in the groove. If the height of the nano-conductive metal paste is lower than the depth of the groove, repeat step S22 until the height of the nano-conductive metal paste is not lower than the depth of the groove.

[0023] Preferably, in the filter packaging method based on a glass substrate according to an embodiment of the present application, in step S21, the solvent is ethanol or ethylene glycol, and organic cellulose is added to the solvent.

[0024] Preferably, in the filter packaging method based on a glass substrate according to an embodiment of the present application, in step A, the thickness of the second glass substrate is 10 microns to 2 millimeters.

[0025] Preferably, in the filter packaging method based on a glass substrate according to an embodiment of the present application, in step D, the height of the metal bump is not less than the height of the encapsulation layer.

[0026] An embodiment of the present application also provides a filter packaging structure based on a glass substrate, including:

[0027] A first glass substrate;

[0028] A second glass substrate, which is disposed on the first glass substrate. A through hole is formed in the middle of the second glass substrate, and a preset circuit is disposed on the second glass substrate;

[0029] A filter chip, which includes a chip substrate, a functional area formed in the middle of the front surface of the chip substrate, and a plurality of electrical signal connection ports located around the functional area. The filter chip is correspondingly disposed on the second glass substrate so that the functional area corresponds to the position of the through hole, and the electrical signal connection ports are electrically connected to the preset circuit;

[0030] An encapsulation layer, which is disposed on the second glass substrate and only wraps the filter chip, and exposes the pad area of the preset circuit;

[0031] Metal bumps, which are electrically connected to the pad area of the preset circuit.

[0032] The filter packaging method based on a glass substrate provided by the embodiment of the present application uses a double-layer glass substrate to form a cavity structure, so that the cavity structure of the filter chip is surrounded by glass. Glass has a very small dielectric constant and a small dielectric loss, which can improve the signal transmission rate, ensure a small signal loss, improve the reliability of the packaging structure, and improve the electrical performance. Description of the Drawings

[0033] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a flowchart of a filter packaging method based on a glass substrate according to an embodiment of the present application.

[0035] Figure 2 Detailed schematic diagrams of the respective steps of a filter packaging method based on a glass substrate according to an embodiment of the present application.

[0036] Figure 3 It is a schematic diagram of the respective steps of a manufacturing method of a second glass substrate in a filter packaging method based on a glass substrate according to an embodiment of the present application. Specific embodiments

[0037] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application.

[0038] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "front" and "back" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this application is usually placed during use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0039] It should also be noted that unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0040] Please refer to Figure 1 , Figure 1 It is a schematic flowchart of a filter packaging method based on a glass substrate according to some embodiments of the present application. The filter packaging method based on a glass substrate includes the following steps:

[0041] A. Provide a first glass substrate, and dispose at least one second glass substrate on one side of the first glass substrate along its thickness direction. A through hole is formed in the middle of the second glass substrate, and a preset circuit is disposed on the second glass substrate;

[0042] B. Provide at least one filter chip, where the filter chip includes a chip substrate, a functional area located in the middle on the front side of the chip substrate, and a plurality of electrical signal connection ports located around the functional area. Correspondingly arrange one filter chip on one second glass substrate, so that the functional area corresponds to the position of the through hole, and electrically connect the electrical signal connection ports to the preset circuit;

[0043] C. Provide a molding compound, perform molding on the second glass substrate, and form a molding layer after curing. The molding layer only wraps the filter chip and exposes the pad area of the preset circuit;

[0044] D. Provide metal bumps and electrically connect the metal bumps to the pad area of the preset circuit;

[0045] E. Cut the first glass substrate to form single discrete filter package structures.

[0046] Please also refer to Figure 2 , Figure 2 , which is a detailed schematic diagram of each step of a filter packaging method based on a glass substrate according to an embodiment of the present application. It should be noted that the second glass substrate 20 can be bonded to the first glass substrate 10 through an adhesive (not shown in the figure). Among them, a through hole 22 is provided in the middle of the second glass substrate 20, and the position where the through hole 22 is located is the area where the functional area 42 of the filter chip 40 is located. The functional area 42 is the area corresponding to the surface interdigital transducer of the chip transducer. In this area, the filter chip 40 is provided with an inner cavity, and a metal vibrating piece is encapsulated on the inner cavity. Combining with the sealed outer cavity formed by the through hole 22 and the first glass substrate 10, the metal vibrating piece can vibrate up and down in the inner cavity and the outer cavity to achieve the filtering performance of the filter, and the inner cavity and the outer cavity are independently sealed, so that the performance of the filter will not be affected.

[0047] Furthermore, the filter chip 40 is an FBAR filter chip, and the chip is obtained by cutting a chip wafer composed of multiple filter chips 40 into single filter chips.

[0048] It should be noted that in order to electrically lead out the electrical signal connection ports 41 of the filter chip 40, corresponding circuits need to be provided on the second glass substrate 20. In practical applications, the preset circuit 21 can be formed by drilling and grooving on the second glass substrate 20 and then electroplating and copper deposition. However, the traditional method of circuit design on a glass substrate is limited to opening holes and it is difficult to fabricate more fine-pitch and more miniaturized packaging circuits. Therefore, preferably, the embodiment of the present application provides a method for fabricating a refined circuit on the second glass substrate 20, which specifically includes the following steps:

[0049] S1. Provide at least one second glass substrate 20, etch through-holes 22 in the middle of the second glass substrate 20, and etch grooves with a preset circuit shape on the front surface of the second glass substrate 20;

[0050] S2. Provide nano-conductive metal particles and fill the grooves with the nano-conductive metal particles;

[0051] S3. Irradiate the nano-conductive metal particles with a laser to sinter the nano-conductive metal particles to form a preset circuit 21.

[0052] In practical applications, to improve production efficiency, a large-panel-level packaging method can be adopted to design the circuit on the second glass substrate 20. As Figure 3 shown, first, provide a whole glass plate 110 made of the same material as the second glass substrate 20, cover the glass plate 110 on a carrier plate 120 through a temporary bonding adhesive layer (not shown in the figure), and make the glass plate 110 into a plurality of second glass substrates 20 with through-holes 22 in the middle and containing a preset circuit 21. Among them, the temporary bonding adhesive layer can adopt common bonding adhesives, such as blue film or other adhesives, and the carrier plate 120 can adopt a glass carrier plate, an organic carrier plate, a stainless steel carrier plate, an alloy carrier plate, an FR2 carrier plate, an FR4 carrier plate, an FR5 carrier plate or a BT resin carrier plate, etc. The types of the temporary bonding adhesive layer and the carrier plate 120 are not limited herein.

[0053] It should be further noted that in practical applications, since the glass plate 110 has high hardness and high brittleness, if an ordinary laser is used for direct drilling or grooving, on the one hand, the glass is easily broken, the drilled holes cannot be made very smooth, and at the same time, residue particles are easily formed around the hole diameter and the circuit groove. And the embodiment of the present application provides a method combining laser modification and chemical etching to form corresponding through-holes 22 and grooves on the glass plate 110. In practical applications, this method specifically includes the following steps:

[0054] First, irradiate and modify the areas 11 with a preset circuit shape and the areas corresponding to the through-holes 22 on the glass plate 110 by using a corresponding laser;

[0055] Then, immerse the glass plate 110 in hydrofluoric acid or hydrogen fluoride solution for etching to form grooves with a preset circuit shape and through-holes 22 on the glass plate 110.

[0056] In practical applications, the above-mentioned laser engraving is performed using one of a carbon dioxide laser, a YAG laser, a semiconductor laser, a green laser, an argon ion laser, an ultraviolet laser, a near-infrared laser, or a diode-pumped solid laser. Preferably, in the chip packaging method based on a transparent plate according to an embodiment of the present application, the laser power range of the laser is between 100 mV and 30 W, and the frequency range is between 50 KHz and 1000 KHz. In practical applications, by controlling the modification area, modification time, and laser parameters, the modification area and chemical etching depth of the glass plate 110 can be adjusted, and finally, the glass plate 110 with a groove or through hole 22 having a preset circuit shape can be obtained.

[0057] The method for manufacturing the glass plate 110 with a groove or through hole 22 having a preset circuit shape by first performing laser modification and then chemical etching will not ablate the glass plate 110. Only the material within the laser irradiation area is modified to break the molecular bonds of the material in this area, and then the modified area of the material can be quickly etched by chemical solution to form a groove or through hole 22, and the etched glass plate 110 can be obtained more quickly. And compared with the traditional circuit forming process, it is not limited to the existing opening size, and a more fine-pitch and more miniaturized packaging circuit can be obtained, and a fine circuit with a line width / line pitch of less than 20 μm / 20 μm can be manufactured.

[0058] Further, in the filter packaging method based on a glass substrate according to an embodiment of the present application, between step S1 and step S2, the following steps are further included: soaking one side of the second glass substrate 20 etched with a groove having a preset circuit shape in a silane coupling agent solution and then drying. The silane coupling agent will undergo a chelation reaction with the glass, which can enhance the bonding force between the second glass substrate 20 and the preset circuit 21.

[0059] In addition, in the filter packaging method based on a glass substrate according to an embodiment of the present application, a metal seed layer can also be sputtered on the inner wall of the groove to enhance the bonding force between the second glass substrate 20 and the preset circuit 21.

[0060] Further, in the filter packaging method based on a glass substrate according to an embodiment of the present application, in step S2, the following steps are included:

[0061] S21. Provide nano-conductive metal particles and a solvent to produce a nano-conductive metal paste;

[0062] S22. Fill the nano-conductive metal paste into the groove;

[0063] S23. Dry and semi-cure the nano-conductive metal paste in the groove. If the height of the nano-conductive metal paste is lower than the depth of the groove, repeat step S22 until the height of the nano-conductive metal paste is not lower than the depth of the groove.

[0064] It should be noted that in the filter packaging method based on a glass substrate according to the embodiments of the present application, in step S21, the nano-conductive metal particles are one or more combinations of nano-conductive metal particles, nano-silver particles, nano-gold particles, or nano-tin particles. The solvent can be ethanol, ethylene glycol, or other volatile organic alcohols, which can also play a role in isolating air, preventing the oxidation of nano-scale conductive metal particles. And an organic cellulose is added to the solvent, which can make the nano-conductive metal particles have better metallurgical bonding between each metal particle after melting, and the circuit forming effect is better. In practical applications, a certain amount of flux can also be added to the solvent, and the flux can reduce the sintering temperature of the nano-conductive metal particles. In step S23, by drying and semi-curing the nano-conductive metal paste and repeatedly filling the nano-conductive metal paste, the circuit becomes more plump.

[0065] After making the preset circuit 21 required for the electrical signal connection ports 41 of the plurality of through holes 22 and the filter chip 40 on the glass plate 110, the temporary bonding adhesive layer can be removed by means such as thermal disassembly to remove the carrier plate 120, and then the glass plate 110 is cut into a plurality of single second glass substrates 20.

[0066] Preferably, in the filter packaging method based on a glass substrate according to the embodiments of the present application, in step A, the thickness of the second glass substrate 20 is 10 microns to 2 millimeters.

[0067] Furthermore, both the first glass substrate 10 and the second glass substrate 20 are made of glass materials such as silicate glass plates. However, in practical applications, preferably, the first glass substrate 10 and the second glass substrate 20 are one of silicate glass plates, calcium salt glass plates, or borosilicate glass plates. Since silicate glass plates have a low dielectric constant and are an inorganic non-metallic, amorphous material with good electrical insulation, chemical stability, shape stability, and isotropy, and have a similar thermal expansion coefficient to silicon, silicate glass plates are preferably used as a substrate material to replace traditional organic substrates and can be applied in more complex environments.

[0068] Preferably, in the filter packaging method based on a glass substrate according to the embodiments of the present application, in step C, the encapsulation layer 50 may adopt an epoxy resin for encapsulation, for example, bisphenol A epoxy resin, brominated epoxy resin, novolac epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, glycidylamine epoxy resin, hydantoin epoxy resin, alicyclic epoxy resin, trihydroxyphenylmethane epoxy resin, bis-xylenol type or bisphenol type epoxy resin or a mixture of these, bisphenol S epoxy resin, bisphenol A novolac epoxy resin, tetraphenylphenolol ethane epoxy resin, heterocyclic epoxy resin, diglycidyl benzoate resin, tetraglycidyl dimethylphenylethane resin, epoxy resin containing naphthyl group, nitrogen-containing epoxy resin, epoxy resin having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resin, copolymer epoxy resin of cyclohexyl maleimide and glycidyl methacrylate, CTBN modified epoxy resin, etc. Of course, the above epoxy resins can be used alone or in combination of two or more.

[0069] Further, in step D, the height of the metal bumps 60 is not less than the height of the encapsulation layer 50, so as to electrically lead out the electrical signal connection ports 41 of the filter chip 40.

[0070] The embodiments of the present application also provide a filter packaging structure based on a glass substrate, including:

[0071] A first glass substrate 10;

[0072] A second glass substrate 20, the second glass substrate 20 is disposed on the first glass substrate 10, a through hole 22 is formed in the middle of the second glass substrate 20, and a preset circuit 21 is disposed on the second glass substrate 20;

[0073] A filter chip 40, the filter chip 40 includes a chip substrate and a functional area 42 formed in the middle of the front surface of the chip substrate and a plurality of electrical signal connection ports 41 located around the functional area 42. The filter chip 40 is correspondingly disposed on the second glass substrate 20 so that the functional area 42 corresponds to the position of the through hole 22 and the electrical signal connection ports 41 are electrically connected to the preset circuit 21;

[0074] An encapsulation layer 50, the encapsulation layer 50 is disposed on the second glass substrate 20 and only wraps the filter chip 40 therein, and exposes the pad area of the preset circuit 21;

[0075] Metal bumps 60, the metal bumps 60 are electrically connected to the pad area of the preset circuit 21.

[0076] Among them, the metal bump 60 can be one of tin solder, silver solder or gold-tin alloy solder. In the embodiment of the present application, the metal bump 60 is a metal ball structure, and the metal ball is welded and implanted into the pad area to realize the electrical lead-out of the preset circuit 21.

[0077] The filter packaging method based on a glass substrate provided by the embodiment of the present application uses a double-layer glass substrate to form a cavity structure in combination, so that the cavity structure of the filter chip is surrounded by glass. Glass has a very small dielectric constant and at the same time has a small dielectric loss, which can improve the signal transmission rate, ensure a small signal loss at the same time, improve the reliability of the packaging structure, and improve the electrical performance.

[0078] The above are only the embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A filter packaging method based on a glass substrate, characterized in that, The method includes the following steps: A. Provide a first glass substrate, and dispose at least one second glass substrate on one side of the first glass substrate along its thickness direction. A through hole is formed in the middle of the second glass substrate, and a preset circuit is disposed on the second glass substrate. B. Provide at least one filter chip. The filter chip includes a chip substrate, a functional area formed in the middle of the front surface of the chip substrate, and a plurality of electrical signal connection ports located around the functional area. Dispose one filter chip on one second glass substrate correspondingly, such that the functional area corresponds to the position of the through hole, and electrically connect the electrical signal connection ports to the preset circuit. The functional area is the area corresponding to the surface interdigital transducer of the chip transducer. An inner cavity is disposed in the filter chip in this area. Combining with the outer cavity formed by the through hole and the first glass substrate, the metal vibrating sheet vibrates up and down in the inner cavity and the outer cavity. C. Provide a plastic encapsulant, perform plastic encapsulation on the second glass substrate, and form a plastic encapsulation layer after curing. The plastic encapsulation layer only wraps the filter chip therein and exposes the pad area of the preset circuit. D. Provide metal bumps, and electrically connect the metal bumps to the pad area of the preset circuit. E. Cut the first glass substrate to form single discrete filter package structures.

2. The filter packaging method based on a glass substrate according to claim 1, characterized in that, Before the step A, the method includes the following steps: S1. Provide at least one second glass substrate, etch a through hole in the middle of the second glass substrate, and etch a groove having a preset circuit shape on the front surface of the second glass substrate. S2. Provide nano-conductive metal particles, and fill the nano-conductive metal particles into the groove. S3. Use a laser to irradiate the nano-conductive metal particles, so that the nano-conductive metal particles are sintered to form the preset circuit.

3. The filter packaging method based on a glass substrate according to claim 2, characterized in that, Between the step S1 and the step S2, the method further includes the following steps: Immerse the side surface of the second glass substrate etched with the groove having a preset circuit shape in a silane coupling agent solution, and then dry.

4. The filter packaging method based on a glass substrate according to claim 2, characterized in that, Between the step S1 and the step S2, the method further includes the following steps: Sputter a metal seed layer on the inner wall of the groove.

5. The filter packaging method based on a glass substrate according to claim 2, characterized in that, In the step S2, the nano-conductive metal particles are one or more combinations of nano-conductive metal particles, nano-silver particles, nano-gold particles or nano-tin particles.

6. The filter packaging method based on a glass substrate according to claim 5, characterized in that, In the step S2, the method includes the following steps: S21. Provide nano-conductive metal particles and a solvent, and make a nano-conductive metal paste. S22. Fill the nano-conductive metal paste into the groove. S23. Dry and semi-cure the nano-conductive metal paste in the groove. If the height of the nano-conductive metal paste is lower than the depth of the groove, repeat the step S22 until the height of the nano-conductive metal paste is not lower than the depth of the groove.

7. The filter packaging method based on a glass substrate according to claim 6, characterized in that, In the step S21, the solvent is ethanol or ethylene glycol, and an organic cellulose is added to the solvent.

8. The filter packaging method based on a glass substrate according to claim 1, characterized in that, In the step A, the thickness of the second glass substrate is 10 microns to 2 millimeters.

9. The filter packaging method based on a glass substrate according to claim 1, characterized in that, In the step D, the height of the metal bump is not less than the height of the encapsulation layer.

10. A filter packaging structure based on a glass substrate, characterized in that, Comprising: A first glass substrate; A second glass substrate, which is disposed on the first glass substrate. A through hole is formed in the middle of the second glass substrate, and a preset circuit is disposed on the second glass substrate; A filter chip, which includes a chip substrate and a functional area located in the middle of the front surface of the chip substrate and a plurality of electrical signal connection ports located around the functional area. The filter chip is correspondingly disposed on the second glass substrate so that the functional area corresponds to the position of the through hole and the electrical signal connection ports are electrically connected to the preset circuit; the functional area is the area corresponding to the surface interdigital transducer of the chip transducer. An inner cavity is provided in the filter chip in this area. Combining with the outer cavity formed by the through hole and the first glass substrate, the metal diaphragm vibrates up and down in the inner cavity and the outer cavity; An encapsulation layer, which is disposed on the second glass substrate and only wraps the filter chip therein, and exposes the pad area of the preset circuit; Metal bumps, which are electrically connected to the pad area of the preset circuit.

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