A packaging structure with a cavity and a corresponding packaging method

Abstract

The present application relates to the technical field of packaging, and discloses a packaging structure with a cavity and a corresponding packaging method, wherein a first encapsulation layer and a second encapsulation layer are used to cover a first encapsulation body arranged on the surface of a substrate, thereby forming a cavity between the first encapsulation body and the substrate; and the flowability of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, so that the first encapsulation layer is located at the edge of the cavity inside and the surface of the substrate outside the cavity, and the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity; so that the bonding force between the encapsulation layer and the substrate is improved, the product reliability is improved, and the cavity can be retained to play the function of the cavity.

Description

Technical Field

[0001] This invention relates to the field of packaging technology, specifically to a packaging structure with a cavity and a corresponding packaging method. Background Technology

[0002] In a packaged product, a cavity needs to be left between one of the encapsulation bodies and the substrate during encapsulation, and the cavity must not be contaminated by the encapsulating material. In order to avoid the encapsulating material contaminating the cavity, encapsulating materials with poor flowability and high viscosity are usually used. However, such encapsulating materials have poor adhesion to the substrate, which can easily lead to product reliability problems. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of poor reliability of existing cavity-based packaging structures, and to provide a cavity-based packaging structure and a corresponding packaging method.

[0004] To achieve the above objectives, the present invention provides a cavity-based packaging structure, comprising:

[0005] substrate;

[0006] The first encapsulation body is disposed on the surface of the substrate via a first connecting structure;

[0007] An encapsulation layer covers the side of the substrate on which the first encapsulation body is located;

[0008] Wherein, there is a cavity between the first encapsulation body and the substrate, and the encapsulation layer includes a first encapsulation layer located on the surface of the substrate and a second encapsulation layer located on the surface of the first encapsulation layer and covering the first encapsulation body;

[0009] The fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, such that the first encapsulation layer is located at the edge inside the cavity and on the substrate surface outside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity.

[0010] As one possible implementation, the thickness of the first encapsulation layer is less than or equal to the height of the side surface of the first encapsulation body facing the substrate from the surface of the substrate.

[0011] As one possible implementation, it also includes:

[0012] The second encapsulation body is disposed on the surface of the substrate via a second connection structure;

[0013] Wherein, the area of ​​the side surface of the first encapsulating body facing the substrate is greater than the area of ​​the side surface of the second encapsulating body facing the substrate, the height of the side surface of the first encapsulating body facing the substrate from the substrate surface is greater than or equal to the height of the side surface of the second encapsulating body facing the substrate from the substrate surface, and the first encapsulation layer is completely filled between the second encapsulating body and the substrate surface.

[0014] As one possible implementation, the thickness of the first encapsulation layer is greater than or equal to the height of the side surface of the second encapsulation body facing the substrate from the substrate surface.

[0015] In one possible implementation, the first encapsulation body is a chip, and the second encapsulation body is an electronic component.

[0016] As one possible implementation, both the first connecting structure and the second connecting structure are metal pillars.

[0017] In one possible implementation, the first encapsulating body has a sensing area on the side surface facing the substrate, and the cavity is formed between the sensing area and the substrate surface.

[0018] In one possible implementation, the sensing area is located in the middle region of the side surface of the first encapsulating body facing the substrate.

[0019] As one possible implementation, it also includes:

[0020] An electromagnetic shielding layer is disposed on the surface of the encapsulation layer.

[0021] Accordingly, the present invention also provides a method for preparing a packaging structure with a cavity, comprising:

[0022] Provide substrate;

[0023] The first encapsulation body is disposed on the surface of the substrate through the first connection structure;

[0024] An encapsulation layer is applied to the side of the substrate where the first encapsulation body is located, thereby forming a cavity between the first encapsulation body and the substrate.

[0025] The encapsulation layer includes a first encapsulation layer located on the surface of the substrate and a second encapsulation layer located on the surface of the first encapsulation layer and covering the first encapsulation body;

[0026] The fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, such that the first encapsulation layer is located at the edge inside the cavity and on the substrate surface outside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity.

[0027] As one possible implementation, the thickness of the first encapsulation layer is less than or equal to the height of the side surface of the first encapsulation body facing the substrate from the surface of the substrate.

[0028] As one possible implementation, after the step of providing the substrate and before the step of covering the side of the substrate where the first encapsulating body is located with an encapsulating layer, the method further includes:

[0029] The second encapsulation body is disposed on the surface of the substrate via a second connection structure;

[0030] Wherein, the area of ​​the side surface of the first encapsulating body facing the substrate is greater than the area of ​​the side surface of the second encapsulating body facing the substrate, the height of the side surface of the first encapsulating body facing the substrate from the substrate surface is greater than or equal to the height of the side surface of the second encapsulating body facing the substrate from the substrate surface, and the first encapsulating layer is filled between the second encapsulating body and the substrate surface when the encapsulation layer is subsequently formed.

[0031] As one possible implementation, the thickness of the first encapsulation layer is greater than or equal to the height of the side surface of the second encapsulation body facing the substrate from the substrate surface.

[0032] In one possible implementation, the first encapsulation body is a chip, and the second encapsulation body is an electronic component.

[0033] In one possible implementation, the first encapsulating body has a sensing area on the side surface facing the substrate, and the cavity is formed between the sensing area and the substrate surface.

[0034] In one possible implementation, the sensing area is located in the middle region of the side surface of the first encapsulating body facing the substrate.

[0035] As one possible implementation, the step of covering the side of the substrate where the first encapsulating body is located with an encapsulating layer includes:

[0036] When the encapsulation layer is in a fluid state, the first encapsulation body disposed on the substrate is pressed into the first encapsulation layer with the first encapsulation layer facing it.

[0037] Until the first encapsulation layer reaches the surface of the substrate, the encapsulation layer is then cured to form an encapsulation layer covering the side of the substrate where the first encapsulation body is located.

[0038] As one possible implementation, after forming the encapsulation layer, it further includes:

[0039] The individual packaging structure is obtained by cutting based on the cutting process.

[0040] As one possible implementation, after obtaining a single package structure, it further includes:

[0041] An electromagnetic shielding layer is formed on the surface of the encapsulation layer of the individual encapsulation structure.

[0042] The beneficial effects of this invention are as follows: This invention provides a packaging structure with a cavity and a corresponding packaging method. A first encapsulation body disposed on the surface of a substrate is covered by a first encapsulation layer and a second encapsulation layer, forming a cavity between the first encapsulation body and the first connecting structure. Furthermore, the fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, such that the first encapsulation layer is located at the edge inside the cavity and on the substrate surface outside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity. This improves the bonding force between the encapsulation layer and the substrate, enhancing product reliability, while retaining the cavity and allowing it to function.

[0043] By providing a second encapsulation body on the substrate and filling the space between the second encapsulation body and the substrate surface with the first encapsulation layer, the different encapsulation requirements of the two encapsulation bodies are met, thereby improving product reliability. Attached Figure Description

[0044] Figure 1 The embodiments provided are exemplary packaging structures for illustrating technical problems;

[0045] Figure 2 The following is an example of a packaging structure provided to illustrate another technical problem;

[0046] Figure 3 This is a schematic diagram of a packaging structure disclosed in an embodiment;

[0047] Figure 4 This is a schematic diagram of another packaging structure disclosed in the embodiment;

[0048] Figures 5-13 This is a schematic diagram of the packaging structure fabrication process disclosed in the embodiment;

[0049] Figure 14 This is a schematic diagram of the packaging structure disclosed in the embodiment, which has an electromagnetic shielding layer. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] See Figure 1 The system comprises a substrate 10, a first encapsulating body 20 located on the surface of the substrate 10, and an encapsulating material 40 encapsulating the first encapsulating body 20. The first encapsulating body 20 is disposed on the surface of the substrate 10 through a first connecting structure 21. A sensing area 22 is provided on the side of the first encapsulating body 20 facing the substrate. A cavity 23 is provided between the first encapsulating body 20 and the substrate 10. Therefore, in order to retain the cavity 23 and prevent the encapsulating material 40 from contaminating the sensing area 22, an encapsulating material 40 with poor flowability and high viscosity is usually used. However, such an encapsulating material 40 has poor adhesion to the substrate 10, which can easily lead to product reliability problems.

[0052] Currently, dry film lamination is also commonly used for encapsulation. However, dry film has poorer flowability than molding compound, which not only increases costs but also causes unevenness such as bumps on the product surface due to its high viscosity and poor flowability, thus affecting product reliability.

[0053] Therefore, to solve the above problems, see [link to relevant documentation]. Figure 3 This embodiment provides a packaging structure with a cavity, including:

[0054] substrate 10;

[0055] The first encapsulation body 20 is disposed on the surface of the substrate 10 via the first connection structure 21;

[0056] Encapsulation layer 1 covers the side of the substrate 10 where the first encapsulation body 20 is located;

[0057] Wherein, a cavity 23 is provided between the first encapsulation body 20 and the substrate 10, and the encapsulation layer 1 includes a first encapsulation layer 50 located on the surface of the substrate 10 and a second encapsulation layer 60 located on the surface of the first encapsulation layer 50 and covering the first encapsulation body 20.

[0058] The fluidity of the material corresponding to the first encapsulation layer 50 is greater than that of the material corresponding to the second encapsulation layer 60, such that the first encapsulation layer 50 is located on the edge 252 inside the cavity and the surface of the substrate 10 outside the cavity 251, while the second encapsulation layer 60 is located on the surface of the first encapsulation layer 50 outside the cavity 251.

[0059] In some embodiments, the cavity-containing packaging structure can be a hollow electronic device with a cavity, such as a SAW (Surface Acoustic Wave) filter, pressure sensor, vibration sensor, MEMS (Micro Electro Mechanical Systems), or surface acoustic wave device.

[0060] In some embodiments, the substrate 10 may be a resin substrate, ceramic substrate, glass substrate, silicon substrate, printed circuit board (PCB), metal substrate, or semiconductor wafer, etc.

[0061] In some embodiments, the substrate 10 has circuitry, which may be a single-layer or multi-layer structure. The circuitry may include metal lines and via interconnect structures electrically connected to the metal lines.

[0062] The substrate 10 has pads on its surface that are connected to the circuit. The pads are made of metal, which may be one or more of aluminum, nickel, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, and silver.

[0063] In some embodiments, the first encapsulation body 20 may be a chip; specifically, it may be an encapsulation body that needs to be disposed on the surface of the substrate and needs to form a cavity between itself and the surface of the substrate, such as a filter chip, a pressure sensor chip, or a vibration sensor chip.

[0064] In some embodiments, the first encapsulation body 20 has a sensing area 22 on one side surface 24 facing the substrate 10. To prevent the sensing area 22 from being contaminated, a cavity 23 is provided between the sensing area 22 and the surface of the substrate 10. Optionally, the sensing area 22 is located in the middle region of the side surface 24 of the first encapsulation body 20 facing the substrate 10.

[0065] In this embodiment, the cavity 23 prevents the encapsulation layer 1 from contaminating the sensing area 22, thereby avoiding any impact on sensing performance.

[0066] In some embodiments, the first connection structure 21 may include one or more of metal balls, metal bumps, metal pillars, etc. The first connection structure 21 and the pads on the surface of the substrate 10 are welded and fixed to achieve electrical connection between the first encapsulation body 20 and the substrate 10.

[0067] In some embodiments, the metal sphere, metal pillar, and metal bump can be made of one or more of aluminum, nickel, tin, tungsten, platinum, copper, titanium, chromium, tantalum, gold, and silver; the metal sphere can be a tin sphere, and the tin sphere can be made of one or more of tin, tin-silver, tin-lead, tin-silver-copper, tin-silver-zinc, tin-zinc, tin-bismuth-indium, tin-indium, tin-gold, tin-copper, tin-zinc-indium, or tin-silver-antimony.

[0068] In some embodiments, the encapsulation layer 1 can be a thermosetting encapsulant or other molding compound with thermosetting encapsulant properties. The thermosetting encapsulant is characterized as follows: it is initially solid, softens into a fluid state upon first heating, and then cures upon heating to a certain temperature. The thermosetting encapsulant can be phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, unsaturated resin, polyurethane, polyimide, etc.

[0069] In some other embodiments, the encapsulation layer 1 may be an encapsulating material that is initially in a fluid state and will solidify after heating.

[0070] In some embodiments, the method by which the encapsulation layer 1 covers the first encapsulation body 20 is not particularly limited. For example, it can be done by using a hot pressing process or other methods that can leave a cavity 23 between the first encapsulation body 20 and the surface of the substrate 10.

[0071] In some embodiments, when the encapsulation layer 1 covers the first encapsulation body 20, see [reference needed]. Figure 3 The encapsulation layer 1 includes a first encapsulation layer 50 located on the surface of the substrate 10 and a second encapsulation layer 60 located on the surface of the first encapsulation layer. The thickness of the second encapsulation layer 60 is greater than the thickness of the first encapsulation layer 50. When the encapsulation is applied using a hot-pressing process or other methods, the surface of the first encapsulation body 20 is also covered with the first encapsulation layer 50, thereby improving the bonding force between the encapsulation layer 1 and the first encapsulation body 20. Specifically, the surface of the first encapsulation body 20 away from the substrate 10 is also covered with the first encapsulation layer 50, while the second encapsulation layer 60 is located on the surface of the first encapsulation layer 50.

[0072] Specifically, in order to maintain a cavity 23 between the first encapsulating body 20 and the surface of the substrate 10, when the thermosetting encapsulating material is used, the hot pressing process is as follows:

[0073] See Figure 7 An encapsulation layer 1 is provided, the encapsulation layer 1 including a first encapsulation layer 50 and a second encapsulation layer 60 located on the surface of the first encapsulation layer 50;

[0074] The encapsulation layer 1 is heated so that the encapsulation material 1 is in a fluid state;

[0075] When the encapsulation layer 1 is in a fluid state, the first encapsulation body 20 disposed on the substrate 10 is pressed into the encapsulation layer 1 facing the first encapsulation layer 50;

[0076] See Figure 8The process continues until the first encapsulation layer 50 reaches the surface of the substrate, thereby covering the first encapsulation body 20, and then the encapsulation layer 1 is cured.

[0077] It should be noted that the fluid state means that when the first encapsulation body 50 disposed on the substrate 10 is pressed into the encapsulation layer 1 facing the first encapsulation layer 50, the encapsulation layer 1 can flow.

[0078] According to the packaging structure provided in the embodiment, the encapsulation layer 1 includes a first encapsulation layer 50 located on the surface of the substrate 10 and a second encapsulation layer 60 located on the surface of the first encapsulation layer; the fluidity of the material corresponding to the first encapsulation layer 50 is greater than the fluidity of the material corresponding to the second encapsulation layer 60, thereby improving the bonding force between the surface of the substrate 10 and the first encapsulation layer 50, thereby improving the overall bonding force between the encapsulation layer 1 and the surface of the substrate 10, and improving product reliability;

[0079] According to the encapsulation structure provided in the embodiment, the fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, and the thickness of the first encapsulation layer is less than that of the second encapsulation layer. This results in the positional relationship between the first encapsulation layer 50, the second encapsulation layer 60, and the cavity 23 as follows: the first encapsulation layer 50 is located on the edge 252 inside the cavity and the surface of the substrate 10 outside the cavity 251, while the second encapsulation layer is located on the surface of the first encapsulation layer 50 outside the cavity 251. It can be seen that the first encapsulation layer can only flow to the surface of the substrate at the edge 252 inside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer 50 outside the cavity 251. This allows the cavity 23 to be retained and its function to be performed, i.e., to avoid contamination of the sensing area 22 by the encapsulation layer 1.

[0080] In this embodiment, the first encapsulation layer 50 is located at the edge 252 inside the cavity and on the surface of the substrate 10 outside the cavity 251. That is, a portion of the first encapsulation layer 50 is located inside the cavity and is only distributed at the edge 252 inside the cavity, without entering the middle part of the cavity 23. The first encapsulation layer 50 is also located on the surface of the substrate 10 outside the cavity 251. In this embodiment, the second encapsulation layer 60 is located on the surface of the first encapsulation layer 50 outside the cavity 251. That is, the second encapsulation layer 60 is not located inside the cavity 23, but on the surface of the first encapsulation layer 50 outside the cavity 251.

[0081] According to the packaging structure provided in the embodiment, see Figure 3When the thickness h2 of the first encapsulation layer 50 is less than the height h1 of the side surface 24 of the first encapsulation body 20 facing the substrate 10 from the surface of the substrate 10, and there is still a gap between the first encapsulation layer 50 and the first encapsulation body 20 located at the edge 252 inside the cavity, in order to prevent the second encapsulation layer 60 from flowing into the cavity 23 through this gap, the fluidity of the material corresponding to the second encapsulation layer is adjusted to be less than the fluidity of the material corresponding to the first encapsulation layer, so that the second encapsulation layer 60 can only be located on the surface of the first encapsulation layer 50 outside the cavity 251, thus avoiding the second encapsulation layer 60 from being squeezed into the cavity 23 due to its large thickness.

[0082] It should be noted that when there is still a gap between the first encapsulation layer 50 located at the cavity edge 252 and the first encapsulation body 20, the sidewall 61 of the second encapsulation layer 60 facing the cavity 23 may be curved.

[0083] In some embodiments, both the first encapsulation layer 50 and the second encapsulation layer 60 contain a variety of fillers. To change the flowability of the materials corresponding to the first and second encapsulation materials, the flowability can be changed by altering the amount of fillers contained in the first and second encapsulation layers, or by changing the placement time of the first and second encapsulation layers in the process flow. It should be noted that the flowability and viscosity of the encapsulation layer materials are related; when the flowability of the encapsulation layer is high, the viscosity of the encapsulation layer is low, and when the flowability of the encapsulation layer is low, the viscosity of the encapsulation layer is high.

[0084] Specifically, when the fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, the second encapsulation layer has high viscosity and low fluidity, can fill a high proportion of particles, has low water absorption and high reliability, and is not easy to enter the cavity; while the first encapsulation layer has low viscosity and high fluidity, but because of its thinness, the first encapsulation layer can only be located at the edge 252 inside the cavity, and is not easy to enter the cavity corresponding to the sensing area.

[0085] In this embodiment, the thickness of the second encapsulation layer is greater than that of the first encapsulation layer. Therefore, the overall fluidity of the encapsulation layer 1 is low, making it difficult to enter the cavity. It can effectively cover the surface of the substrate and the chip, thereby enhancing the bonding force between the encapsulation layer and the substrate, as well as between the encapsulation layer and the first encapsulation body, and improving the reliability of the product.

[0086] In some embodiments, the thickness h2 of the first encapsulation layer 50 located at the edge 252 inside the cavity is less than the height h1 of the side surface 24 of the first encapsulation body 20 facing the substrate 10 from the surface of the substrate 10, thereby preventing the first encapsulation layer 50 from contaminating the side surface 24 of the first encapsulation body 20 facing the substrate 10.

[0087] In some embodiments, the height h1 of the side surface 24 of the first encapsulating body 20 facing the substrate 10 from the surface of the substrate 10 can be reduced, such that the thickness h2 of the first encapsulating layer 50 at the edge 252 inside the cavity is equal to the height h1 of the side surface 24 of the first encapsulating body 20 facing the substrate 10 from the surface of the substrate 10. This ensures that the first encapsulating layer 50 only contacts the edge of the side surface 24 of the first encapsulating body 20 facing the substrate 10, thereby avoiding contamination of the sensing area 22 located in the middle region.

[0088] Furthermore, such as Figure 2 As shown, the substrate 10 surface is further provided with a second encapsulation body 30; the second encapsulation body 30 is disposed on the surface of the substrate 10 through a second connecting structure 31; in this structure, the cavity 23 cannot be contaminated by the encapsulation material 40, and the area around the second connecting structure 31 between the second encapsulation body 30 and the surface of the substrate 10 needs to be filled with encapsulation material 40, otherwise product reliability problems may easily occur.

[0089] The encapsulating material 40 is classified according to its flowability and viscosity, into low-viscosity, high-flowability encapsulating material 40 and high-viscosity, low-flowability encapsulating material 40. When using a low-viscosity, high-flowability encapsulating material 40, although it can fill the space between the second encapsulation body 30 and the substrate 10, it will also fill the cavity 23. When using a high-viscosity, low-flowability encapsulating material, although it will not fill the cavity 23, it also cannot fill or fully fill the space between the second encapsulation body 30 and the substrate 10, thus causing product reliability issues. (See [link to relevant documentation]). Figure 1 This means that no encapsulating material is filled between the second encapsulation body 30 and the surface of the substrate 10. Furthermore, using an encapsulating material 40 with high viscosity and low flowability will reduce the bonding force between the encapsulating material 40 and the substrate 10.

[0090] Therefore, to solve the above problems, see Figure 4 The embodiments also provide a packaging structure, in Figure 3 In addition to the structure, the surface of the substrate 10 also includes:

[0091] The second encapsulation body 30 is disposed on the surface of the substrate 10 via the second connection structure 31;

[0092] Wherein, the area of ​​the side surface 24 of the first encapsulating body 20 facing the substrate 10 is greater than the area of ​​the side surface 32 of the second encapsulating body 30 facing the substrate 10, and the height h1 of the side surface of the first encapsulating body 20 facing the substrate 10 from the surface of the substrate 10 is greater than or equal to the height h3 of the side surface of the second encapsulating body 30 facing the substrate 10 from the surface of the substrate 10, so that while the first encapsulating layer 50 covers the edge 252 inside the cavity, the first encapsulating layer 50 can also fill the space between the second encapsulating body 30 and the surface of the substrate 10, thereby improving product reliability.

[0093] For example, the height h3 of the side surface of the second encapsulating body 30 facing the substrate can be set to be in the range of 5um to 20um, and the height h1 of the side surface of the first encapsulating body 20 facing the substrate can be set to be in the range of 10um to 40um.

[0094] In some embodiments, the second encapsulation body 30 can be an electronic component, wherein the size of the chip is much larger than the electronic component, approximately ten times or more. Therefore, it is possible to fill the space between the second encapsulation body 30 and the surface of the substrate 10 with the first encapsulation layer 50, while the first encapsulation layer is only located on the surface of the substrate 10 at the edge 252 inside the cavity.

[0095] Specifically, the second encapsulation body 30 can be a transistor (e.g., a p-channel / n-channel metal-oxide-semiconductor field-effect transistor (pMOSFET / nMOSFET), a bipolar junction transistor (BJT), a high-voltage transistor, a high-frequency transistor, etc.), a diode, a resistor, a capacitor, an inductor, a fuse, or other suitable components.

[0096] In some other embodiments, the second encapsulation body 30 may also be other types of chips that do not require forming a cavity with the substrate.

[0097] In some embodiments, the second connection structure 31 may include one or more of metal balls, metal bumps, metal pillars, etc. The second connection structure is welded and fixed to the pads on the surface of the substrate to realize the electrical connection between the second encapsulation body 30 and the substrate 10; wherein, the specific materials of the metal balls, metal bumps, and metal pillars are described in the existing description.

[0098] In some embodiments, in order to make the height h1 of the side surface of the first encapsulating body facing the substrate from the substrate surface greater than the height h3 of the side surface of the second encapsulating body facing the substrate from the substrate surface, the height of the first connecting structure can be set to be greater than the height of the second connecting structure.

[0099] In some embodiments, when the substrate 10 is provided with a second encapsulation body 30, and the encapsulation layer 1 covers the side of the substrate provided with the first encapsulation body 20, the encapsulation layer 1 will also cover the second encapsulation body 30.

[0100] In some embodiments, when the encapsulation layer 1 covers the first encapsulation body 20 and the second encapsulation body 30, see [reference needed]. Figure 4 The encapsulation layer 1 includes a first encapsulation layer 50 located on the surface of the substrate 10 and a second encapsulation layer 60 located on the surface of the first encapsulation layer. When the encapsulation is applied using a hot-pressing process or other methods, the surfaces of the first encapsulation body 20 and the second encapsulation body 30 are also covered with the first encapsulation layer 50, thereby improving the bonding force between the encapsulation layer 1 and the first encapsulation body 20 and the second encapsulation body 30, respectively. Specifically, the first encapsulation layer 50 is also covered on the side of the first encapsulation body 20 away from the substrate and the side of the second encapsulation body 30 away from the substrate, while the second encapsulation layer 60 is located on the surface of the first encapsulation layer 50.

[0101] In some embodiments, the fluidity of the material corresponding to the first encapsulation layer 50 is greater than that of the material corresponding to the second encapsulation layer 60, and the thickness of the second encapsulation layer 60 is greater than that of the first encapsulation layer 50. The thinner thickness of the first encapsulation layer 50 results in lower overall fluidity of the encapsulation layer 1, making it less likely to enter the cavity. This allows it to effectively cover the surfaces of the substrate, the first encapsulation body, and the second encapsulation body, thereby enhancing the bonding force between the encapsulation layer and the substrate, as well as between the encapsulation layer and the first and second encapsulation bodies. Furthermore, the fluidity of the material corresponding to the first encapsulation layer 50 and the thickness of the first encapsulation layer 50 ensure that the space between the second encapsulation body 30 and the surface of the substrate 10 is completely filled with the first encapsulation layer 50, thus enhancing the reliability of the product.

[0102] In some embodiments, the thickness h2 of the first encapsulation layer can be set to be greater than or equal to the height h3 of the side surface of the second encapsulation body facing the substrate from the substrate surface, so that the first encapsulation layer can fill the area around the second connection structure between the second encapsulation body and the substrate surface.

[0103] In some embodiments, for example, when the height h3 of the side surface of the second encapsulation body facing the substrate is in the range of 5um to 20um from the surface of the substrate, the thickness of the first encapsulation layer can be set to be in the range of 5um to 20um, and the thickness of the second encapsulation layer can be set to be in the range of 200um to 500um.

[0104] In some embodiments, see Figure 14 The surface of the encapsulation layer is further provided with an electromagnetic shielding layer 80 to achieve electromagnetic shielding and protection; wherein, the electromagnetic shielding layer 80 may include a first stainless steel layer located on the surface of the encapsulation layer, a copper layer located on the surface of the first stainless steel layer, and a second stainless steel layer located on the surface of the copper layer: wherein, the thickness of the stainless steel layer may be set to be approximately 0.1 μm, the thickness of the copper layer to be approximately 3 μm to 7 μm, and the thickness of the second stainless steel layer to be approximately 0.1 μm.

[0105] However, in some other embodiments, depending on the type of encapsulation, the surface of the encapsulation layer 1 may not have an electromagnetic shielding layer 80.

[0106] According to the packaging structure provided in the embodiments, traditional encapsulation processes can be used without the need for new equipment, resulting in low packaging costs, good workability, and high adhesion between the encapsulation layer and the product, leading to high product reliability.

[0107] In some embodiments, a method for preparing a packaging structure having a cavity is also provided, comprising:

[0108] See Figure 5 Substrate 10 is provided;

[0109] See Figure 6 The first encapsulation body 20 is disposed on the surface of the substrate 10 through the first connecting structure 21;

[0110] See Figures 7-8 An encapsulation layer 1 is provided on one side of the substrate 10 where the first encapsulation body 20 is located, thereby forming a cavity 23 between the first encapsulation body 20 and the substrate 10.

[0111] The encapsulation layer 1 includes a first encapsulation layer 50 located on the surface of the substrate 10 and a second encapsulation layer 60 located on the surface of the first encapsulation layer 50 and covering the first encapsulation body 20.

[0112] The fluidity of the material corresponding to the first encapsulation layer 50 is greater than that of the material corresponding to the second encapsulation layer 60, such that the first encapsulation layer 50 is located on the edge 252 inside the cavity and the substrate surface outside the cavity 251, while the second encapsulation layer 60 is located on the surface of the first encapsulation layer 50 outside the cavity 251.

[0113] In some embodiments, the step of covering the side of the substrate 10 where the first encapsulation body 20 is located with the encapsulation layer 1 includes:

[0114] See Figure 7 The encapsulation layer 1 is placed in the mold 70. When the encapsulation layer 1 is in a fluid state, the first encapsulation body 20 disposed on the substrate 10 is pressed into the encapsulation layer 1 facing the first encapsulation layer 50.

[0115] See Figure 8 Until the first encapsulation layer 50 reaches the surface of the substrate 10 and forms the state shown in the figure, the encapsulation layer 1 is then cured to form an encapsulation layer 1 covering the side of the substrate 10 where the first encapsulation body 20 is located.

[0116] In some embodiments, the step of placing the encapsulation layer 1 in the mold 70 may be: first placing a second encapsulation layer 60 in the mold 70, and then placing a first encapsulation layer 50 on the surface of the second encapsulation layer 60 in the mold 70.

[0117] In some embodiments, the first encapsulation layer 50 and the second encapsulation layer 60 can be made of different materials or the same material, thereby reducing material preparation and material development time.

[0118] In some embodiments, when the first encapsulation layer 50 and the second encapsulation layer 60 are made of the same material, the viscosity curve of the encapsulation material can be used, that is, the change pattern of the encapsulation material having a high viscosity at the beginning, a low viscosity after heating, maintaining a low viscosity for a period of time, and the viscosity of the encapsulation material increasing due to the chain reaction after further heating.

[0119] First, a second encapsulating layer 60 is placed in the mold cavity of mold 70. When the viscosity of the second encapsulating layer 60 decreases after heating, a first encapsulating layer 50 is placed in. Heating continues, and when the viscosity of the second encapsulating layer 60 increases again due to the gel chain reaction, while the viscosity of the first encapsulating layer 50 decreases after heating, the product is placed in for encapsulation. This results in the first encapsulating layer 50 being located at the edge 252 inside the cavity and on the substrate surface outside the cavity 251, while the second encapsulating layer 60 is located on the surface of the first encapsulating layer 50 outside the cavity 251. This increases the bonding force by increasing the contact area with the substrate.

[0120] In some embodiments, when the encapsulation layer 1 corresponds to a thermosetting encapsulant, the encapsulant needs to be heat-treated to make the encapsulation layer 1 a fluid state. In other embodiments, the encapsulation layer 1 in a fluid state can also be provided directly.

[0121] In some embodiments, the heating conditions for heat treatment of the encapsulation layer to make the encapsulation layer 1 a fluid state are as follows: for example, the heating temperature can be 40°C to 100°C, the pressure can be 0.1 MPa to 10 MPa, and the time can be 0.3 minutes to 10 minutes. In addition, if the improvement of the adhesion and conformability between the encapsulation layer and the substrate is considered, stamping can be performed under reduced pressure conditions (0.1 kPa to 5 kPa).

[0122] In some embodiments, the method for curing the encapsulation layer 1 may be heating; the heating conditions for curing may be, for example, a heating temperature of 100°C or higher, or an upper limit of 200°C or lower, and a heating time of 10 minutes or more, or an upper limit of 180 minutes or lower; in addition, pressure may be applied as needed, which may be 0.1 MPa or higher, or an upper limit of 10 MPa or lower.

[0123] In some embodiments, after forming the encapsulation layer, the method further includes:

[0124] Print a pattern on the surface of the encapsulation layer;

[0125] See Figure 9 Based on the cutting process, the result is as follows: Figure 3 The diagram shows a single encapsulation structure including the first encapsulation body 20.

[0126] In some embodiments, after the step of providing the substrate and before the step of covering the side of the substrate with the first encapsulating body with an encapsulating layer, the method further includes:

[0127] See Figure 10 The second encapsulation body 30 is disposed on the surface of the substrate 10 through the second connecting structure 31;

[0128] Wherein, the area of ​​the side surface 24 of the first encapsulating body 20 facing the substrate 10 is greater than the area of ​​the side surface 32 of the second encapsulating body 30 facing the substrate 10, and the height h1 of the side surface of the first encapsulating body 20 facing the substrate 10 from the surface of the substrate 10 is greater than or equal to the height h3 of the side surface of the second encapsulating body 30 facing the substrate 10 from the surface of the substrate 10, such that the first encapsulation layer 50 is completely filled between the second encapsulating body 30 and the surface of the substrate 10, and the first encapsulation layer 50 is completely filled between the second encapsulating body 30 and the surface of the substrate 10 when the encapsulation layer 1 is subsequently formed.

[0129] See Figures 11-12 The step of covering the side of the substrate 10 with the first encapsulation body 20 with the encapsulation layer 1 includes:

[0130] The substrate 10 is provided with a first encapsulation body 20 and a second encapsulation body 30 covering the encapsulation layer 1.

[0131] In some embodiments, after the encapsulation layer 1 is formed:

[0132] Print a pattern on the surface of the encapsulation layer;

[0133] See Figure 13 The material is cut using a cutting process to obtain a single encapsulation structure comprising the first encapsulation body 20 and the second encapsulation body 30.

[0134] In some embodiments, after obtaining a single package structure, see Figure 14 It also includes: forming an electromagnetic shielding layer 80 on the surface of the encapsulation layer 1 of the single encapsulation structure.

[0135] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A packaging structure with a cavity, characterized in that, include: substrate; The first encapsulation body is disposed on the surface of the substrate via a first connecting structure; An encapsulation layer covers the side of the substrate on which the first encapsulation body is located; Wherein, there is a cavity between the first encapsulation body and the substrate, and the encapsulation layer includes a first encapsulation layer located on the surface of the substrate and a second encapsulation layer located on the surface of the first encapsulation layer and covering the first encapsulation body; The fluidity of the material corresponding to the first encapsulation layer is greater than that of the material corresponding to the second encapsulation layer, such that the first encapsulation layer is located at the edge inside the cavity and on the substrate surface outside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity.

2. The cavity-containing packaging structure according to claim 1, characterized in that, The thickness of the first encapsulation layer is less than or equal to the height of the side surface of the first encapsulation body facing the substrate from the surface of the substrate.

3. The cavity-containing packaging structure according to claim 1, characterized in that, Also includes: The second encapsulation body is disposed on the surface of the substrate via a second connection structure; Wherein, the area of ​​the side surface of the first encapsulating body facing the substrate is greater than the area of ​​the side surface of the second encapsulating body facing the substrate, the height of the side surface of the first encapsulating body facing the substrate from the substrate surface is greater than or equal to the height of the side surface of the second encapsulating body facing the substrate from the substrate surface, and the first encapsulation layer is completely filled between the second encapsulating body and the substrate surface.

4. The cavity-containing packaging structure according to claim 3, wherein the thickness of the first encapsulation layer is greater than or equal to the height of the side surface of the second encapsulation body facing the substrate from the surface of the substrate.

5. The cavity-containing packaging structure according to claim 3, characterized in that, The first encapsulation body is a chip, and the second encapsulation body is an electronic component.

6. The cavity-containing packaging structure according to claim 3, characterized in that, Both the first connecting structure and the second connecting structure are metal pillars.

7. The cavity-containing packaging structure according to claim 1, characterized in that, The first encapsulating body has a sensing area on the side surface facing the substrate, and there is a cavity between the sensing area and the substrate surface.

8. The cavity-containing packaging structure according to claim 7, characterized in that, The sensing area is located in the middle region of the side surface of the first encapsulating body facing the substrate.

9. The cavity-containing packaging structure according to claim 1, characterized in that, Also includes: An electromagnetic shielding layer is disposed on the surface of the encapsulation layer.

10. A method for preparing a packaging structure with a cavity, characterized in that, include: Provide substrate; The first encapsulation body is disposed on the surface of the substrate through the first connection structure; An encapsulation layer is applied to the side of the substrate where the first encapsulation body is located, thereby forming a cavity between the first encapsulation body and the substrate. The encapsulation layer includes a first encapsulation layer located on the surface of the substrate and a second encapsulation layer located on the surface of the first encapsulation layer and covering the first encapsulation body; the fluidity of the material corresponding to the first encapsulation layer is greater than the fluidity of the material corresponding to the second encapsulation layer, such that the first encapsulation layer is located at the edge inside the cavity and on the surface of the substrate outside the cavity, while the second encapsulation layer is located on the surface of the first encapsulation layer outside the cavity.

11. The method for preparing a cavity-containing encapsulation structure according to claim 10, characterized in that, The thickness of the first encapsulation layer is less than or equal to the height of the side surface of the first encapsulation body facing the substrate from the surface of the substrate.

12. The method for preparing a cavity-containing encapsulation structure according to claim 10, characterized in that, The method further includes, after the step of providing the substrate and before the step of covering the side of the substrate where the first encapsulating body is located with an encapsulating layer: The second encapsulation body is disposed on the surface of the substrate via a second connection structure; Wherein, the area of ​​the side surface of the first encapsulating body facing the substrate is greater than the area of ​​the side surface of the second encapsulating body facing the substrate, the height of the side surface of the first encapsulating body facing the substrate from the substrate surface is greater than or equal to the height of the side surface of the second encapsulating body facing the substrate from the substrate surface, and the first encapsulating layer is filled between the second encapsulating body and the substrate surface when the encapsulation layer is subsequently formed.

13. The method for preparing a cavity-containing encapsulation structure according to claim 12, wherein the thickness of the first encapsulation layer is greater than or equal to the height of the side surface of the second encapsulation body facing the substrate from the surface of the substrate.

14. The method for preparing a cavity-containing encapsulation structure according to claim 12, characterized in that, The first encapsulation body is a chip, and the second encapsulation body is an electronic component.

15. The method for preparing a cavity-containing encapsulation structure according to claim 10, characterized in that, The first encapsulating body has a sensing area on the side surface facing the substrate, and there is a cavity between the sensing area and the substrate surface.

16. The method for preparing a cavity-containing encapsulation structure according to claim 10, characterized in that, The step of covering the side of the substrate where the first encapsulating body is located with an encapsulating layer includes: When the encapsulation layer is in a fluid state, the first encapsulation body disposed on the substrate is pressed into the first encapsulation layer with the first encapsulation layer facing it. Until the first encapsulation layer reaches the surface of the substrate, the encapsulation layer is then cured to form an encapsulation layer covering the side of the substrate where the first encapsulation body is located.

17. The method for preparing a cavity-containing encapsulation structure according to claim 10, characterized in that, After the encapsulation layer is formed, it also includes: The individual packaging structure is obtained by cutting based on the cutting process.

18. The method for preparing a cavity-containing encapsulation structure according to claim 17, characterized in that, After obtaining a single package structure, the following is also included: An electromagnetic shielding layer is formed on the surface of the encapsulation layer of the individual encapsulation structure.

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