Filter structure integrated with IPD chip, packaging module and preparation method

Abstract

The application discloses a filter structure integrated with an IPD chip, a packaging module and a preparation method. The filter structure comprises an IPD chip, a filter chip, a film layer and a plastic sealing layer. The IPD chip is electrically connected with a module substrate. The filter chip is arranged on the surface of the IPD chip and is electrically connected with the IPD chip. The film layer covers the outer side of the IPD chip and the filter chip. The plastic sealing layer is plastic sealed on the surface of the IPD chip to completely cover the film layer. The filter structure integrates the IPD chip needed to be attached on the module substrate on the filter, so as to increase the space utilization rate of the subsequent attachment on the applied module substrate. The IPD chip is integrated as the filter packaging substrate without increasing the size of the filter itself, the filter packaging is realized, the filter forms a complete circuit, and the use effect of the filter is ensured.

Description

Technical Field

[0001] This invention relates to a filter structure with an integrated IPD chip, as well as a packaged module containing the filter structure and a method for fabricating the filter structure, belonging to the field of semiconductor packaging technology. Background Technology

[0002] Currently, acoustic filters typically employ packaging methods such as CSP (Chip Scale Package), DSSP (Die-Level SAW Package), and WLP (Wafer-Level Package). When integrated into a package module, the circuitry on the substrate needs to be matched. Furthermore, other chips within the package module also require capacitors, resistors, inductors, etc., for circuit adjustments, leading to the increasingly widespread application of IPD (Integrated Passive Device) chips.

[0003] However, IPD chips are essentially discrete devices, mainly used as auxiliary filters and other chips that require circuit matching to form a complete circuit. They are mounted on the module substrate and occupy a certain amount of space. With the increasing demand for miniaturization of semiconductor structures, space on the substrate is becoming increasingly scarce. Therefore, achieving the same function while reducing the substrate space is a technical challenge that researchers urgently need to solve.

[0004] Chinese invention patent ZL 201410173160.6 discloses a three-dimensional stacked structure and fabrication method for integrated passive device wafer-level packaging, including a wafer-level packaged chip and an IPD chip; the IPD chip includes a glass substrate, with an IPD device and a metal wiring layer disposed on the front side of the glass substrate; TGV holes are etched on the back side of the glass substrate, and a back metal wiring layer is disposed on the back side of the glass substrate and the inner surface of the TGV holes, and solder balls are disposed on the pads of the back metal wiring layer, with the solder balls connected to the PCB board. The fabrication method of the three-dimensional stacked structure includes the following steps: (1) stacking the wafer-level packaged chip and the IPD chip on the glass substrate; (2) etching TGV holes on the back side of the IPD chip and fabricating a back metal wiring layer on the back side of the glass substrate; (3) etching the back metal wiring layer into two insulating parts; fabricating pads and solder balls on the two parts of the back metal wiring layer, and connecting the PCB board through the solder balls. Summary of the Invention

[0005] The primary technical problem to be solved by this invention is to provide a filter structure that integrates an IPD chip.

[0006] Another technical problem to be solved by the present invention is to provide a packaged module for a filter structure.

[0007] Another technical problem to be solved by the present invention is to provide a method for fabricating a filter structure with an integrated IPD chip.

[0008] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0009] According to a first aspect of the present invention, a filter structure integrating an IPD chip is provided, comprising:

[0010] IPD chip, used for electrical connection with module substrate;

[0011] A filter chip is disposed on the surface of the IPD chip and is electrically connected to the IPD chip;

[0012] A thin film layer covers the outer side of the IPD chip and the filter chip;

[0013] A molding layer is applied to the surface of the IPD chip to completely cover the thin film layer.

[0014] Preferably, the filter chip includes:

[0015] The filter chip body is located above the surface of the IPD chip;

[0016] A conductive pad is formed on the bonding surface of the filter chip body and electrically connected to the IPD chip, so that a receiving cavity is formed between the bonding surface of the filter chip body and the surface of the IPD chip; wherein, the bonding surface of the filter chip body is close to the surface of the IPD chip;

[0017] Interdigitated transducers are formed on the bonding surface of the filter chip body and located within the receiving cavity.

[0018] Preferably, the thin film layer is replaced by a barrier wall, which is disposed between the IPD chip and the filter chip body to prevent the molding compound from entering the receiving cavity.

[0019] Preferably, the retaining wall is disposed on the outside of the conductive pad;

[0020] Alternatively, the barrier is disposed inside the conductive pad and outside the interdigital transducer.

[0021] Preferably, the molding material of the molding layer satisfies at least the following conditions: the particle diameter of the molding material is greater than a preset diameter; and / or, the flow velocity of the molding material is less than a preset flow velocity; and / or, the viscosity of the molding material is greater than a preset viscosity.

[0022] Preferably, the filter structure further includes a carrier plate, on the surface of which a plurality of IPD chips are disposed, with a preset spacing between adjacent IPD chips to allow for single-piece cutting by a cutting blade.

[0023] According to a second aspect of the present invention, a packaged module for a filter structure is provided, comprising:

[0024] A module substrate, wherein a preset circuit is built into the module substrate;

[0025] In the above-described filter structure, the IPD chip of the filter structure is mounted on the surface of the module substrate and electrically connected to the preset circuit.

[0026] According to a third aspect of the present invention, a method for fabricating a filter structure integrating an IPD chip is provided, comprising the following steps:

[0027] An colloid is applied to the surface of the carrier plate;

[0028] Multiple IPD chips are respectively attached to preset positions on the surface of the carrier board;

[0029] Multiple filter chips are respectively mounted on the surface of multiple IPD chips, so that the conductive pads of the multiple filter chips are electrically connected to the multiple IPD chips respectively.

[0030] All IPD chips and all filter chips are covered with a polymer film to form a thin film layer;

[0031] A molding compound is used to seal the surface of the carrier plate and completely cover the film layer to form a molding layer;

[0032] After molding, the wafer is cut into individual pieces and the carrier board is removed to form a filter structure with a single integrated IPD chip.

[0033] Preferably, the method of covering all IPD chips and all filter chips with a polymer film to form a thin film layer is replaced by:

[0034] A barrier is set between each group of IPD chips and filter chips, such that the barrier is located outside the conductive pad of the filter chip.

[0035] Preferably, the method of covering all IPD chips and all filter chips with a polymer film to form a thin film layer is replaced by:

[0036] A barrier is set between each group of IPD chips and filter chips, such that the barrier is located inside the conductive pad of the filter chip and outside the interdigital transducer of the filter chip.

[0037] Compared with existing technologies, the filter structure and fabrication method with integrated IPD chips provided in this invention increase the space utilization of the module substrate by integrating the IPD chip, which needs to be mounted on the module substrate, onto the filter. Furthermore, without increasing the size of the filter itself, the integrated IPD chip serves as the filter packaging substrate, achieving filter packaging and forming a complete circuit, thus ensuring the filter's performance. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a filter structure integrating an IPD chip provided in the first embodiment of the present invention;

[0039] Figure 2 A schematic diagram of another filter structure with an integrated IPD chip provided in the second embodiment of the present invention;

[0040] Figure 3 A schematic diagram of another filter structure with an integrated IPD chip provided in the second embodiment of the present invention;

[0041] Figure 4 A schematic diagram of another filter structure with an integrated IPD chip provided in the second embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a filter structure integrating an IPD chip provided in the third embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the packaging module of a filter structure provided in the fourth embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the carrier plate in the fifth embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of the structure of mounting an IPD chip on a carrier board in the fifth embodiment of the present invention;

[0046] Figure 9 This is a schematic diagram of the structure of mounting a filter chip on an IPD chip in the fifth embodiment of the present invention;

[0047] Figure 10 This is a schematic diagram of the structure of the polymer film covering the fifth embodiment of the present invention;

[0048] Figure 11 This is a schematic diagram of the encapsulation structure in the fifth embodiment of the present invention. Detailed Implementation

[0049] The technical content of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0050] <First Embodiment>

[0051] like Figure 1 As shown, the filter structure with integrated IPD chip provided in the first embodiment of the present invention includes IPD chip 1, filter chip 2, thin film layer 3 and molding compound layer 4.

[0052] IPD chip 1 is used for electrical connection with module substrate 10 (see reference) Figure 6 (As shown); Filter chip 2 is disposed on the upper surface of IPD chip 1 and is electrically connected to IPD chip 1; Thin film layer 3 covers the outer side of IPD chip 1 and filter chip 2; Molding layer 4 is molded onto the surface of IPD chip 1 to completely cover thin film layer 3.

[0053] In this embodiment, the IPD chip 1 serves as the substrate of the filter. A complete filter structure is formed by sequentially mounting and molding the filter chip 2, thin film layer 3, and molding layer 4. The IPD chip 1 can have electrical connection lines formed on its surface (top and bottom surfaces in this embodiment) using a TSV process. This allows the bottom surface of the IPD chip 1 to be electrically connected to the module substrate 10 after the filter structure is integrated, and the top surface of the IPD chip 1 to be electrically connected to the filter chip 2. Therefore, in practical use, by integrating the IPD chip 1, which would otherwise be mounted on the module substrate 10, onto the filter, the space utilization of the applied module substrate is increased. This embodiment integrates the IPD chip 1 as a filter packaging substrate without increasing the size of the filter itself, achieving filter packaging and forming a complete circuit, thus ensuring the filter's performance.

[0054] In the above embodiment, the filter chip 2 includes a filter chip body 21, a conductive pad 22, and an interdigital transducer 23. The filter chip body 21 is located above the IPD chip 1 and has a bonding surface 211 near the upper surface of the IPD chip 1. The conductive pad 22 is formed on the bonding surface 211 of the filter chip body and is electrically connected to the IPD chip 1. Because the conductive pad 22 has a certain thickness, when the conductive pad 22 is electrically connected to the upper surface of the IPD chip 1, the bonding surface 211 of the filter chip body, the upper surface of the IPD chip, and the conductive pad 22 together form a rectangular cavity 201. The interdigital transducer 23 (i.e., IDT) is formed on the bonding surface 211 of the filter chip body and is located within the cavity 201.

[0055] In the above embodiment, the height of the interdigital transducer 23 (i.e. Figure 1The distance between the top and bottom directions should be less than the thickness of the conductive pad 22, and the interdigital transducer 23 should be in... Figure 1 The interdigital transducer 23 is positioned between two conductive pads 22 in the left-right direction. Therefore, when the conductive pads 22 are electrically connected to the upper surface of the IPD chip 1, the interdigital transducer 23 can be precisely positioned within the receiving cavity 201. Furthermore, the interdigital transducer 23 has a certain safety gap with the upper surface of the IPD chip 1, preventing the interdigital transducer 23 from being squeezed and deformed. In addition, it is understood that... Figure 1 In this process, the conductive pads 22 are not only present on the left and right sides of the interdigital transducer 23, but also on the front and rear sides of the interdigital transducer 23. Furthermore, from the front and rear direction, the interdigital transducer 23 is still located between the front and rear conductive pads 22, thus completely surrounding the interdigital transducer 23.

[0056] In the above embodiment, the thin film layer 3 is a polymer thin film. By covering all the chips (i.e., the IPD chip + the filter chip) with the polymer thin film, a protective layer is formed, which can prevent the molding compound from entering the filter chip 2 during the subsequent molding process and affecting the performance of the filter chip 2, thereby improving the overall safety. In this embodiment, the specific material of the thin film layer 3 is not limited and can be selected according to actual needs.

[0057] In the above embodiments, the molding layer 4 is preferably an epoxy resin molding material. This molding material has fluidity. Under a certain molding pressure, the viscosity of the molding material changes with time during the molding process. Therefore, the main material parameters are: filler size is generally greater than 5 μm, and filler content is greater than 80 wt%. The content ratio affects the viscosity and fluidity of the material. In addition, the larger the size, the less likely it is to break through the film and enter the cavity at the bottom of the filter chip. In this embodiment, the molding material of the molding layer 4 should at least meet one of the following conditions: First, the particle diameter of the molding material is greater than a preset diameter; second, the flow rate of the molding material is less than a preset flow rate; third, the viscosity of the molding material is greater than a preset viscosity. It can be understood that when the particle diameter of the molding material is larger, it is less likely to flow into the receiving cavity 201 through the gap between the filter chip body 21 and the IPD chip 1, and conversely, it is easier to flow into the receiving cavity 201. Similarly, the slower the flow rate of the encapsulating material, the less likely it is to flow into the receiving cavity 201 through the gap between the filter chip body 21 and the IPD chip 1; conversely, the easier it is to flow into the receiving cavity 201. The higher the viscosity of the encapsulating material, the less likely it is to flow into the receiving cavity 201 through the gap between the filter chip body 21 and the IPD chip 1; conversely, the easier it is to flow into the receiving cavity 201. Therefore, when selecting encapsulating materials, materials with larger particle diameters, slower flow rates, and higher viscosity should be selected as much as possible. This reduces the possibility of encapsulating material entering the receiving cavity 201 during the encapsulation process, thus avoiding contamination of the filter. It is understood that the three conditions listed in this embodiment are only preferred selection conditions. In other embodiments, other selection conditions can be added. Furthermore, the more conditions the encapsulating material meets, the better the encapsulation effect. The encapsulating material can be adaptively selected according to the actual encapsulation requirements.

[0058] <Second Embodiment>

[0059] like Figures 2-4 As shown, based on the first embodiment, the second embodiment of the present invention provides another filter structure. Compared with the first embodiment, the difference in this embodiment is that the thin film layer 3 is replaced with the barrier wall 3A.

[0060] Specifically, the barrier 3A is disposed between the IPD chip 1 and the filter chip body 21 to prevent the molding compound from entering the receiving cavity 201. The material of the barrier 3A is not limited here; it can be a rigid material (e.g., a protruding pillar) or a flexible material (e.g., a polymer film surrounding the mating surface of the filter chip body 21), and can be adapted according to actual needs.

[0061] Furthermore, it is understandable that the function of the barrier 3A is to prevent the molding compound from entering the cavity 201, thereby protecting the interdigital transducer 23. Therefore, the placement of the barrier 3A only needs to ensure the safe protection of the interdigital transducer 23. Figure 2 As shown, in one embodiment, the barrier 3A is disposed on the outside of the conductive pad 22; as Figure 3 As shown, in another embodiment, the baffle 3A is disposed inside the conductive pad 22 and located outside the interdigital transducer 23; as Figure 4 As shown, in another embodiment, the left-side barrier 3A is disposed on the outside of the conductive pad 22, and the right-side barrier 3A is disposed on the inside of the conductive pad 22 and on the outside of the interdigital transducer 23.

[0062] Except for the structure described above, the rest of the structure in this embodiment is the same as that in the first embodiment, and will not be repeated here.

[0063] <Third Embodiment>

[0064] like Figure 5 As shown, based on the first embodiment, the third embodiment of the present invention also provides a filter structure. Compared with the first embodiment, the difference in this embodiment is that the filter structure further includes a carrier plate 5.

[0065] Specifically, the carrier board 5 is a rectangular plate with a large surface area, allowing multiple IPD chips 1 to be disposed on its surface with a preset spacing between adjacent IPD chips to form a dicing channel 20. This enables the packaging of multiple filter structures at once, and the dicing channel 20 can be cut using a dicing tool to form a single filter structure, thus improving the production efficiency of the filter structure.

[0066] Except for the structure described above, the rest of the structure in this embodiment is the same as that in the first embodiment, and will not be repeated here.

[0067] <Fourth Embodiment>

[0068] like Figure 6 As shown, based on the first embodiment, the fourth embodiment of the present invention also provides a packaging module for a filter structure, including a module substrate 10 and any one of the filter structures in the first to third embodiments described above.

[0069] The module substrate 10 has a preset circuit on its surface. During installation, the IPD chip 1 of the filter structure is attached to the surface of the module substrate 10 and electrically connected to the preset circuit. This eliminates the need for the matching circuit of the module substrate 10, which makes the packaging area of ​​the filter structure on the module substrate 10 smaller and facilitates the placement of other semiconductor devices that need to be packaged on the module substrate 10.

[0070] <Fifth Embodiment>

[0071] like Figures 7-11 As shown, the sixth embodiment of the present invention provides a method for fabricating a filter structure with an integrated IPD chip, used to fabricate the filter structure provided in the first embodiment. Specifically, it includes steps S1 to S6:

[0072] S1: Apply colloid to the surface of carrier plate 5.

[0073] like Figure 7 As shown, a rectangular carrier plate 5 is prepared in advance, and double-sided tape is adhered to the surface of the rectangular carrier plate 5. It is understood that in other embodiments, the adhesive is not limited to double-sided tape, but can be in liquid or semi-solid form, and the adhesive is applied by spreading.

[0074] S2: Mount IPD chip 1.

[0075] like Figure 8 As shown, multiple IPD chips 1 are respectively pasted on the surface of the carrier board 5 at preset positions, so that there is a preset distance between two adjacent IPD chips 1 to form a cutting channel 20.

[0076] S3: Mount filter chip 2.

[0077] like Figure 9 As shown, after the IPD chip 1 is mounted, multiple filter chips 2 are mounted on the surface of multiple IPD chips 1 respectively, so that the conductive pads 22 of multiple filter chips 2 are electrically connected to multiple IPD chips 1 respectively.

[0078] S4: Cover polymer film.

[0079] like Figure 10 As shown, after all the filter chips 2 are mounted on each IPD chip 1, a polymer film is used to cover all the IPD chips 1 and all the filter chips 2 to form a thin film layer 3.

[0080] S5: Plastic sealing.

[0081] like Figure 11 As shown, after the film layer 3 is covered, a molding compound (epoxy resin in this embodiment) is used to seal the surface of the carrier plate 5, completely covering the film layer 3 to form the molding compound layer 4.

[0082] S6: Cut the order.

[0083] After molding, the cutting channel 20 needs to be cut into individual pieces using a dicing tool, and the carrier board 5 needs to be removed to form a filter structure of a single integrated IPD chip (e.g., Figure 1 (As shown).

[0084] It is understood that in the above method, multiple filter structures can be fabricated at once by placing multiple IPD chips 1 on the carrier board 5 simultaneously. In another embodiment, only one IPD chip 1 can be placed on the carrier board 5 to produce one filter structure at a time; the specific choice can be adapted according to production needs.

[0085] Furthermore, in the above embodiments, step S4 can also be replaced by S4A:

[0086] S4A: Set up retaining wall 3A.

[0087] Specifically, after the filter chip 2 is mounted on each IPD chip 1, a barrier 3A is set between each group of IPD chips 1 and filter chips 2 to prevent the molding compound from entering the filter chip 2 during molding. The location of the barrier 3A is the same as in the second embodiment, and will not be described again here.

[0088] In summary, the filter structure and fabrication method of the integrated IPD chip provided in the embodiments of the present invention have the following beneficial effects:

[0089] 1. The IPD chip 1, which needs to be mounted on the module substrate 10, is integrated onto the filter, thereby increasing the space utilization of the module substrate where it is applied. Without increasing the size of the filter itself, the integrated IPD chip 1 serves as the filter packaging substrate, realizing filter packaging and forming a complete circuit, thus ensuring the filter's performance.

[0090] 2. The molding material of the molding layer 4 meets the preset conditions, thereby reducing the possibility of the molding material entering the receiving space 201 and ensuring the molding effect.

[0091] 3. The packaging process is simple, which can effectively improve the production efficiency of filter structures.

[0092] The filter structure, packaging module, and fabrication method of the integrated IPD chip 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 filter structure integrating an IPD chip, characterized in that... include: IPD chip, used for electrical connection with module substrate; A filter chip is disposed on the surface of the IPD chip and electrically connected to the IPD chip; wherein the filter chip includes: a filter chip body located above the surface of the IPD chip; a conductive pad formed on the bonding surface of the filter chip body and electrically connected to the IPD chip, such that a receiving cavity is formed between the bonding surface of the filter chip body and the surface of the IPD chip; wherein the bonding surface of the filter chip body is close to the surface of the IPD chip; and an interdigital transducer formed on the bonding surface of the filter chip body and located within the receiving cavity; A thin film layer covers the outer side of the IPD chip and the filter chip; A molding layer is applied to the surface of the IPD chip to completely cover the thin film layer; The IPD chip serves as the substrate of the filter. A complete filter structure is formed by sequentially mounting and molding the filter chip, thin film layer, and molding layer. The top and bottom surfaces of the IPD chip include electrical connection lines, which enable the bottom surface of the IPD chip to be electrically connected to the module substrate and the top surface of the IPD chip to be electrically connected to the filter chip after the filter structure is integrated.

2. The filter structure as described in claim 1, characterized in that: The thin film layer is replaced by a barrier wall, which is disposed between the IPD chip and the filter chip body to prevent the molding compound from entering the cavity.

3. The filter structure as described in claim 2, characterized in that: The retaining wall is disposed on the outside of the conductive pad; or, The barrier is located inside the conductive pad and outside the interdigital transducer.

4. The filter structure as described in claim 1, characterized in that: The molding material of the molding layer must at least satisfy the following conditions: the particle diameter of the molding material is greater than a preset diameter; and / or, the flow velocity of the molding material is less than a preset flow velocity; and / or, the viscosity of the molding material is greater than a preset viscosity.

5. The filter structure as described in claim 1, characterized in that... It also includes a carrier plate, on the surface of which are disposed a plurality of IPD chips, with a preset spacing between two adjacent IPD chips, so that a cutting blade can perform single-piece cutting.

6. A packaged module for a filter structure, characterized in that... include: A module substrate, wherein a preset circuit is built into the module substrate; The filter structure as described in any one of claims 1 to 5, wherein the IPD chip of the filter structure is mounted on the surface of the module substrate and electrically connected to the preset circuit.

7. A method for fabricating a filter structure with an integrated IPD chip, used to fabricate the filter structure as described in claim 1, characterized in that... Includes the following steps: An colloid is applied to the surface of the carrier plate; Multiple IPD chips are respectively attached to preset positions on the surface of the carrier board; Multiple filter chips are respectively mounted on the surface of multiple IPD chips, so that the conductive pads of the multiple filter chips are electrically connected to the multiple IPD chips respectively. All IPD chips and all filter chips are covered with a polymer film to form a thin film layer; A molding compound is used to seal the surface of the carrier plate and completely cover the film layer to form a molding layer; After molding, the wafer is cut into individual pieces and the carrier board is removed to form a filter structure with a single integrated IPD chip.

8. The preparation method according to claim 7, characterized in that... The method of covering all IPD chips and all filter chips with a polymer film to form a thin film layer is replaced by: A barrier is set between each group of IPD chips and filter chips, such that the barrier is located outside the conductive pad of the filter chip.

9. The preparation method according to claim 7, characterized in that... The method of covering all IPD chips and all filter chips with a polymer film to form a thin film layer is replaced by: A barrier is set between each group of IPD chips and filter chips, such that the barrier is located inside the conductive pad of the filter chip and outside the interdigital transducer of the filter chip.

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