A cavity filter chip module and a packaging method

Abstract

The application discloses a cavity filter chip module and a packaging method. The packaging method comprises the following steps: connecting a plurality of cavity filter chips on an integral substrate; pasting a film on the cavity filter chips and softening the film to form a film covering the cavity filter chips; connecting non-cavity filter chips or devices to the surface of the substrate; forming a plastic packaging material on the substrate by using a plastic packaging process, so that the plastic packaging material is not filled at the bottom of the cavity filter chips but is filled at the bottom of the non-cavity filter chips or devices; singulating and completing subsequent processes. The application can form a closed cavity under the cavity filter chips in the module, realize functions, avoid the problem that other non-cavity filter chips or devices cannot be filled by plastic packaging, and improve the reliability of the module. The production process is simple, the cost is low, and the yield is high.

Description

Technical Field

[0001] This invention relates to a packaging method for a cavity filter chip module, and also to a corresponding cavity filter chip module, belonging to the field of semiconductor packaging technology. Background Technology

[0002] In wireless networks, when data needs to be transmitted, the user terminal (UE) must continuously listen to the Physical Downlink Control Channel (PLC) and send and receive data according to the instruction messages sent by the network side. This results in relatively high power consumption and data transmission latency for the UE. Therefore, the 3GPP standard protocol introduced a discontinuous reception mechanism (Drx) power-saving strategy in LTE systems, defined at the physical layer Media Access Control (MAC). Consequently, the radio frequency front-end used for fifth-generation wireless communication includes a diversity receiver path (Drx), which is essentially a receiver path used to assist the main receiver (RX) in signal reception.

[0003] Traditional diversity receiver path (Drx) modules include multiple filter chips. They often use a coating to isolate the outer molding compound and ensure that the bottom of the filter forms a cavity. However, the bottom of other chips or devices in the module cannot be well filled due to the coating, which can easily lead to solder bridging and short circuits. At the same time, the reliability of non-filter chips and devices cannot be guaranteed due to insufficient molding compound filling.

[0004] Chinese invention application No. 202110468684.8 discloses a filter system-level hybrid packaging module and packaging method. The hybrid packaging module includes: a first filter that filters received signals in a first frequency band; a second filter that filters received signals in a second frequency band different from the first frequency band; a substrate with pads on one side and molding compound on the other side, the molding compound providing a first space for the first filter and a second space different from the first space for the second filter; the surface of the molding compound is coated with a metallic coating, separating the first and second spaces; and traces connecting the first and second filters are provided on the substrate. Summary of the Invention

[0005] The primary technical problem to be solved by this invention is to provide a packaging method for a cavity filter chip module.

[0006] Another technical problem to be solved by the present invention is to provide a corresponding cavity filter chip module.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0008] According to a first aspect of the present invention, a method for packaging a cavity filter chip module is provided, comprising the following steps:

[0009] Multiple cavity filter chips are connected on the entire substrate;

[0010] A film is applied to the cavity filter chip and softened to form a coating that seals the cavity filter chip;

[0011] Connect non-cavity filter chips or devices to the substrate surface;

[0012] A molding process is used to form a molding compound on a substrate, so that the molding compound is not filled at the bottom of the cavity filter chip but is filled at the bottom of the non-cavity filter chip or device;

[0013] Cut the order and complete the subsequent processes.

[0014] Preferably, the polymer film used for bonding the cavity filter chip is a film that matches the size of a single cavity filter chip.

[0015] Preferably, when applying the film to the cavity filter chip, the identification points on the polymer film are used to align one of the polymer films with one of the plurality of cavity filter chips one by one.

[0016] Preferably, the surface of the non-cavity filter chip or device does not have the polymer film.

[0017] Preferably, the first side length L1 of the polymer film satisfies: L <L1≤α(L+D),

[0018] Wherein, L is the first side length of the substrate of the cavity filter chip; and the distance between the substrate and the projection of the non-cavity filter chip or device onto the substrate in the first direction is D; α is a preset value greater than 1 and less than 10.

[0019] According to a second aspect of the present invention, a method for packaging a cavity filter chip is provided, comprising the following steps:

[0020] Multiple cavity filter chips and non-cavity filter chips or devices are connected on the entire substrate.

[0021] A film is applied to the cavity filter chip and softened to form a coating that seals the cavity filter chip;

[0022] A molding process is used to form a molding compound on a substrate, so that the molding compound is not filled at the bottom of the cavity filter chip but is filled at the bottom of the non-cavity filter chip or device;

[0023] Cut the order and complete the subsequent processes.

[0024] Preferably, the polymer film used for bonding the cavity filter chip is a film that matches the size of a single cavity filter chip.

[0025] Preferably, when applying the film to the cavity filter chip, an identification point on a polymer film is used to align one of the polymer films with one of the plurality of cavity filter chips.

[0026] Preferably, the surface of the non-cavity filter chip or device does not have the polymer film.

[0027] Preferably, the first side length L1 of the polymer film satisfies: L <L1≤α(L+D),

[0028] Wherein, L is the first side length of the substrate of the cavity filter chip; and the distance between the substrate and the projection of the non-cavity filter chip or device onto the substrate in the first direction is D; α is a preset value greater than 1 and less than 10.

[0029] According to a third aspect of the present invention, a cavity filter chip module is provided, comprising a substrate, a cavity filter chip connected to the substrate, a coating, a non-cavity filter chip or device, and a molding compound.

[0030] The cavity filter chip includes a substrate, metal electrodes, and a barrier wall located beneath the substrate.

[0031] The substrate and the barrier wall together form a closed space with the substrate, creating a resonant cavity for the metal electrode.

[0032] The coating covers the surface of the cavity filter chip, while the surface of the non-cavity filter chip or device does not have the coating.

[0033] Preferably, the molding compound covers the surface of the cavity filter chip and the surface of the non-cavity filter chip or device, and the coating is exposed on the cut surface of the molding compound near the cavity filter chip.

[0034] Preferably, the first side length L1 of the polymer film satisfies: L <L1≤α(L+D),

[0035] Wherein, L is the first side length of the substrate of the cavity filter chip; and the distance between the substrate and the projection of the non-cavity filter chip or device onto the substrate in the first direction is D; α is a preset value greater than 1 and less than 10.

[0036] Compared with existing technologies, the cavity filter chip module and packaging method provided by this invention can form a sealed cavity under the cavity filter chip in the chip module to achieve the function, while avoiding the problem of other non-cavity filter chips or devices being unable to be plastic-encapsulated, thus improving the reliability of the module. The manufacturing process is simple, low-cost, and has a high yield rate. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the steps of connecting the cavity filter chip to the substrate in the first embodiment of the present invention;

[0038] Figure 2A This is a schematic diagram illustrating the steps of coating the cavity filter chip in the first embodiment of the present invention;

[0039] Figure 2B for Figure 2A A schematic diagram of the thin film preparation process;

[0040] Figure 3 This is a schematic diagram illustrating the steps of connecting a non-cavity filter chip to a substrate in the first embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the molding process in the first embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the steps of the cavity filter chip module packaging method provided in the second embodiment of the present invention;

[0043] Figure 6 for Figure 5 The embodiment shown is a schematic diagram of the cavity filter chip module. Detailed Implementation

[0044] The technical content of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0045] <First Embodiment>

[0046] like Figures 1 to 4 As shown, the packaging method for a cavity filter chip module provided in the first embodiment of the present invention includes the following steps:

[0047] S1: Connect multiple cavity filter chips on the entire substrate.

[0048] like Figure 1As shown, a plurality of cavity filter chips 2 are connected to the entire substrate 1, for example, the cavity filter chips 2 are flip-chip mounted on the substrate 1. In this embodiment, the cavity filter chip is a filter chip such as SAW or BAW, but this does not constitute a limitation to the present invention. After the cavity filter chip 2 is connected to the substrate 1, a closed space is enclosed among the substrate 21, the barrier wall 22 and the substrate 1, forming a resonant cavity of the metal electrode 3.

[0049] Here, the cavity filter chip can be connected to the substrate by a mounting or welding process.

[0050] S2: laminating and softening the cavity filter chip to form a covering film that encloses the cavity filter chip.

[0051] As Figure 2A shown, a polymer film is used to laminate the surface of the cavity filter chip, and then softened to form the covering film 4, so that the polymer film covers the surface of the substrate 21 and the surface of the barrier wall 22 of the cavity filter chip, and also covers the surface of the substrate surrounding the cavity filter chip. Therefore, the chip is completely sealed by the covering film, so as to ensure that no molding material enters between the cavity filter chip and the substrate.

[0052] As Figure 2B shown, before step 2, a film matched with the size of the cavity filter chip 2 is prepared in advance. Assuming that the distance between the substrate 21 and the projection of a non-cavity filter chip or device 5 on the substrate 1 in a first direction (for example Figure 2B and Figure 3 the horizontal direction in ) is D; the side length of the substrate 21 in the first direction is L. Here, matching with the size of the cavity filter chip 2 means that the side length L1 of the film 2 in the first direction is greater than the side length L of the substrate 21 of the cavity filter chip 2 in the first direction; and the side length L1 of the film 2 in the first direction is less than or equal to L+D. That is, L<L1≤α(L+D). Similarly, if the side length of the substrate 21 in the second direction (perpendicular to the first direction) is L', and the spacing between the cavity filter chip and the non-cavity filter chip or device 5 in this direction is D', then the side length L2 of the film 2 in the second direction satisfies: L'<L2≤β(L'+D'). Wherein, both α and β are preset values greater than 1 and less than or equal to 10, which are preselected according to actual needs. Preferably, 1<α<3 and 1<β<3.

[0053] As Figure 2B shown, the film matched with the size of the cavity filter chip 2 is obtained by cutting a polymer film. Moreover, the plurality of cut films are still adhered to one film to form a tape.

[0054] In one embodiment of the present invention, step S2 further comprises the following film preparation steps:

[0055] S21: Divide a polymer film into multiple films that match the size of the cavity filter chip;

[0056] S22: Use laser marking to create identification points (marks) at preset positions on each film;

[0057] S23: Multiple films are arranged in a matrix to form a tape for use in coating.

[0058] In step S22, the preset positions are typically at least two corners of the thin film. Identification points are marked on each corner using a laser for precise positioning and identification during subsequent lamination. The film is then fabricated into a roll for use in the next step of laminating individual cavity filter chips.

[0059] Furthermore, the coating step in step S2 includes the following sub-steps:

[0060] S24: Place the substrate 1, which has been connected with multiple cavity filter chips, on the film-attaching platform, and align the film 4, which corresponds to the size of the cavity filter chip, by scanning the identification points to accurately attach it to the front side of the corresponding cavity filter chip 2.

[0061] S25: Remove the release film from the surface of film 4 using a transfer film of the same size (the viscosity between the transfer film and the release film should be greater than the viscosity between the release film and film 4, so that the transfer film can carry the release film away from film 4).

[0062] S26: The coated substrate 1 is placed into the vacuum chamber of the laminator. The laminator heats and evacuates the substrate, so that the thin film 4 is tightly attached to the upper surface and the periphery of the cavity filter chip 2. The bottom of the cavity filter chip 2 forms a resonant cavity with the substrate 1 through the surrounding of the thin film 4.

[0063] S3: Connect the non-cavity filter chip or device 5 to the substrate surface.

[0064] like Figure 2A As shown, non-cavity filter chips or devices are connected to the substrate using conventional soldering, mounting, or wire bonding processes. In this embodiment, non-cavity filter chips or devices refer to other types of chips or devices besides filter chips. In other words, the space between the non-cavity filter chip or device and the substrate needs to be adequately filled with encapsulating material.

[0065] S4: A molding compound 6 is formed on the substrate using a molding process, such that the molding compound is not filled at the bottom of the cavity filter chip but fills the bottom of the non-cavity filter chip or device, for example... Figure 3 As shown.

[0066] S5: Cut the order and complete subsequent processes to form the package structure, such as... Figure 4 As shown.

[0067] The main feature of this patent is that each individual cavity filter 2 in the packaging module is individually coated with a film to form a thin film 4 only on the surface of the cavity filter 2, but without coating other devices or chips. This not only forms a sealed cavity under the cavity filter 2 to achieve its function, but also avoids the problem of insufficient filling of other devices by plastic encapsulation, thereby improving the reliability of the module.

[0068] The simple process provided by this invention enables the selective omission of encapsulation material on the underside of some chips on an entire substrate, while simultaneously filling the underside of other chips with encapsulation material. Thus, this invention applies a film to the filter chip on the same substrate, but leaves other chips or devices unencapsulated. This creates a sealed cavity on the filter chip to achieve its function, while avoiding the problem of other chips or devices being unable to be encapsulated, thereby improving the reliability of the module.

[0069] <Second Embodiment>

[0070] like Figure 5 As shown, the cavity filter chip module packaging method provided in this embodiment differs from the first embodiment in that it first connects the non-cavity filter chip or device to the substrate before coating. Specifically, the cavity filter chip module packaging method provided in this embodiment includes the following steps:

[0071] S11: Connect multiple cavity filter chips 2 and non-cavity filter chips or devices 5 on the entire substrate.

[0072] Multiple cavity filter chips 2 are connected on the entire substrate 1. After the cavity filter chips 2 are connected to the substrate 1, they form a closed space between the substrate 21, the barrier 22 and the substrate 1, forming the resonant cavity of the metal electrode 3.

[0073] Here, the cavity filter chip can be attached to the substrate using mounting or soldering processes. Non-cavity filter chips or devices 5 are attached to the substrate 1 using conventional soldering, mounting, or wire bonding processes.

[0074] Depending on the actual situation, multiple cavity filter chips 2 and non-cavity filter chips or devices 5 can be connected to the substrate 1 in the same process step, or they can be connected to the substrate 1 in two separate process steps.

[0075] S12: Apply and soften the film to the cavity filter chip to form a coating that seals the cavity filter chip.

[0076] A polymer film is applied to the surface of the cavity filter chip, and then softened to form a coating 4. This polymer film covers the surface of the substrate 21 and the surface of the barrier 22 of the cavity filter chip, and also covers the surface of the substrate surrounding the cavity filter chip. Therefore, the F chip is completely sealed by the coating, ensuring that no encapsulating material enters between the cavity filter chip and the substrate.

[0077] In one embodiment of the present invention, step S2 further includes the following film preparation step:

[0078] S21: Divide a polymer film into multiple films that match the size of a single cavity filter chip;

[0079] S22: Use laser marking to create identification points (marks) at preset positions on each film;

[0080] S23: Multiple films are arranged in a matrix to form a roll for use in film coating.

[0081] In step S22, the preset positions are typically at least two corners of the thin film. Identification points are marked on each corner using a laser for precise positioning and identification during subsequent lamination. The film is then fabricated into a roll for use in the next step of laminating individual cavity filter chips.

[0082] Furthermore, the coating step in step S2 includes the following sub-steps:

[0083] S24: Using the identification points on the polymer film, align one of the polymer films with one of the plurality of cavity filter chips one by one.

[0084] Specifically, the substrate 1, which has been connected to multiple cavity filter chips, is placed on a film-attaching platform. A thin film 4, corresponding to the size of the cavity filter chip, is then aligned by scanning identification points to accurately attach it to the front of the corresponding cavity filter chip 2.

[0085] S25: Remove the release film from the surface of film 4 using a transfer film of the same size.

[0086] Since the viscosity between the transfer film and the release film should be greater than that between the release film and the film 4, the transfer film can carry the release film away from the film 4. Therefore, the release film on the surface of the film 4 is removed using a transfer film of the same size.

[0087] S26: The coated substrate 1 is placed into the vacuum chamber of the laminator. The laminator heats and evacuates the substrate, so that the thin film 4 is tightly attached to the upper surface and the periphery of the cavity filter chip 2. The bottom of the cavity filter chip 2 forms a resonant cavity with the substrate 1 through the surrounding of the thin film 4.

[0088] S13: Using a molding process, molding material 6 is formed on the substrate, such that the molding material is not filled at the bottom of the cavity filter chip but is filled at the bottom of the non-cavity filter chip or device.

[0089] The product is encapsulated using a C-MD injection molding machine under relatively low mold closing pressure, so that the encapsulating material 6 covers the film 4 while flowing under the non-cavity filter chip or device 5 to complete the bottom filling (however, the bottom of the cavity filter chip 2 still retains the vacuum cavity 24).

[0090] S14: Cut the entire encapsulated substrate into individual pieces and complete subsequent processes to form a package structure and complete the product packaging process.

[0091] <Third Embodiment>

[0092] This invention also provides a cavity filter chip module, including a substrate 1, a cavity filter chip 2 connected to the substrate 1, a coating 4, a non-cavity filter chip or device 5, and a molding compound 6. The cavity filter chip 2 includes a substrate 21, a metal electrode 3, and a barrier 22 located below the substrate 21. The substrate 21 and the barrier 22, together with the substrate 1, form a closed space, creating a resonant cavity for the metal electrode 3. The coating 4 covers the surface of the substrate 21 and the surface of the barrier 22 of the cavity filter chip, and also covers the surface of the substrate surrounding the cavity filter chip. The molding compound 6 encapsulates the entire substrate, the cavity filter chip 2, and the non-cavity filter chip or device 5 to provide protection.

[0093] The molding compound 6 covers both the surface of the cavity filter chip and the surface of the non-cavity filter chip or device. On the cut surface 61 of the molding compound 6 near the cavity filter chip (the cut surface formed during the die-cutting process), the overlay 4 is exposed. This design minimizes the package size while ensuring that the overlay completely covers the cavity filter chip, thus guaranteeing package quality.

[0094] It should be noted that the cavity filter chip module in this embodiment is prepared using the cavity filter chip module packaging method provided by the present invention.

[0095] Compared with existing technologies, the cavity filter chip module and packaging method provided by this invention can form a sealed cavity under the cavity filter chip in the chip module to achieve the function, while avoiding the problem of other non-cavity filter chips or devices being unable to be plastic-encapsulated, thus improving the reliability of the module. The manufacturing process is simple, low-cost, and has a high yield rate.

[0096] The cavity filter chip module and packaging method provided by this invention have been described in detail above. Any obvious modifications made by those skilled in the art without departing from the essence of this invention will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

Claims

1. A packaging method for a cavity filter chip module, characterized in that... comprising the following steps: connecting a plurality of cavity filter chips onto an entire substrate; laminating and softening the cavity filter chips to form a covering film that encloses the cavity filter chips; connecting non-cavity filter chips or devices onto the surface of the substrate; forming a molding material on the substrate by a molding process, such that the molding material is not filled at the bottom of the cavity filter chips but is filled at the bottom of the non-cavity filter chips or devices; singulating and completing subsequent processes, when laminating and softening the cavity filter chips, aligning one of the polymer films with one of the plurality of cavity filter chips one by one by using identification points on the polymer films, placing the laminated substrate into a vacuum chamber of a laminator, and heating and vacuumizing the substrate through the vacuum chamber of the laminator, so that the film closely adheres to the upper surface and the periphery of the cavity filter chip, and a resonant cavity is formed between the bottom of the cavity filter chip and the substrate through the enclosure of the film; a side length L1 of the film in a first direction satisfies: L < L1 ≤ α(L + D), wherein L is a side length of a substrate of the cavity filter chip in the first direction; D is a spacing in the first direction between a projection of the substrate and a projection of the non-cavity filter chip or device on the substrate; and α is a preset value greater than 1 and less than 10; before laminating the cavity filter chips, the method comprises the following film preparation steps: dividing a plurality of films matched with the size of a single cavity filter chip on one polymer film; forming identification points at preset positions of each film by laser marking; arranging the plurality of films into a tape in a matrix arrangement for later use in laminating.

2. The packaging method for a cavity filter chip module according to claim 1, characterized in that: when laminating and softening the cavity filter chips, before placing the laminated substrate into the vacuum chamber of the laminator, the method further comprises the following steps: placing the substrate with a plurality of connected cavity filter chips on a laminating platform, and aligning the film corresponding to the size of the cavity filter chip by scanning the identification points to precisely laminate the film onto the front surface of the corresponding cavity filter chip; removing a release film on the surface of the film by using a transfer film of the same size.

3. The packaging method for the cavity filter chip module as described in claim 2, characterized in that: a side length L2 of the polymer film in a second direction satisfies: L' < L1 ≤ β(L' + D'), wherein L' is the side length of the substrate in the second direction, D' is the spacing between the cavity filter chip and the non-cavity filter chip or device in this direction, and β is a preset value greater than 1 and less than or equal to 10, which is pre-selected according to actual requirements.

4. The packaging method for the cavity filter chip module as described in claim 3, characterized in that: the preset value α satisfies 1 < α < 3; and the preset value β satisfies 1 < β < 3.

5. The packaging method for the cavity filter chip module as described in claim 4, characterized in that: the surface of the non-cavity filter chip or device is not provided with the polymer film.

6. A method for packaging a cavity filter chip, characterized in that... comprising the following steps: connecting a plurality of cavity filter chips and non-cavity filter chips or devices on an entire substrate; applying a film to the cavity filter chips and softening the film to form a covering film that encloses the cavity filter chips; forming a molding compound on the substrate by a molding process, such that the molding compound is not filled at the bottom of the cavity filter chips but filled at the bottom of the non-cavity filter chips or devices; performing singulation and completing subsequent processes, when applying a film to the cavity filter chips, aligning one of the polymer films with one of the plurality of cavity filter chips one by one by using identification points on the polymer films, placing the covered substrate into a vacuum chamber of a laminator, heating and vacuuming the substrate through the vacuum chamber of the laminator, so that the film tightly adheres to the upper surface and the periphery of the cavity filter chip, and a resonant cavity is formed between the bottom of the cavity filter chip and the substrate surrounded by the film; the side length L1 of the polymer film in a first direction satisfies: L<L1≤α(L+D), wherein L is the side length of the substrate of the cavity filter chip in the first direction; D is the spacing in the first direction between the projection of the substrate and the projection of the non-cavity filter chip or device on the substrate; α is a preset value greater than 1 and less than 10, before applying a film to the cavity filter chips, the following film preparation steps are comprised: dividing a polymer film into a plurality of films matched with the size of a single cavity filter chip; forming identification points at preset positions of each film by laser marking; arranging the plurality of films into a tape in a matrix arrangement for subsequent film covering use.

7. The cavity filter chip packaging method as described in claim 6, characterized in that: the polymer film used for applying a film to a cavity filter chip is a film matched with the size of a single cavity filter chip.

8. The cavity filter chip packaging method as described in claim 7, characterized in that: the side length L2 of the polymer film in a second direction satisfies: L'<L2≤β(L'+D'), wherein L' is the side length of the substrate in the second direction, D' is the spacing between the cavity filter chip and the non-cavity filter chip or device in the second direction, and β is a preset value greater than 1 and less than or equal to 10 pre-selected according to actual requirements.

9. A cavity filter chip module, characterized in that... comprising a substrate, a cavity filter chip connected to the substrate, a covering film, a non-cavity filter chip or device, and a molding compound, the cavity filter chip is prepared by the packaging method for a cavity filter chip module according to any one of claims 1 to 5.

10. The cavity filter chip module as described in claim 9, characterized in that: the molding compound covers the surface of the cavity filter chip and the surface of the non-cavity filter chip or device, and the covering film is exposed on a cutting surface of the molding compound adjacent to the cavity filter chip.

11. The cavity filter chip module as described in claim 10, characterized in that: the side length L2 of the polymer film in the second direction satisfies: L'<L2≤β(L'+D'), wherein L' is the side length of the substrate in the second direction, D' is the spacing between the cavity filter chip and the non-cavity filter chip or device in the second direction, and β is a preset value greater than 1 and less than or equal to 10 pre-selected according to actual requirements.

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