Filter module packaging structure with SMD device

Abstract

The utility model discloses a filter module packaging structure with an SMD device. The filter module packaging structure comprises a substrate; the filter module is arranged on the substrate, the filter module comprises a plurality of filter chips and a plurality of non-filter chips, the non-filter chips comprise SOI chips and SMD devices mounted on the peripheries of the SOI chips, and the mounting distances between the SMD devices and the SOI chips are smaller than a preset threshold value; the isolating membrane is arranged on the upper surfaces of the substrate and the filter module, and a breakable membrane region is formed on the isolating membrane corresponding to a gap between the SMD device and the SOI chip; and a plastic package body, wherein the substrate and the filter module are coated with the plastic package body. The position layout of the non-filter chip in the filter module is designed and changed, so that the toughness of the isolating membrane material is weakened by utilizing the distance so as to fill the bottom of the non-filter chip with the plastic package material, and the position of the filter chip is covered with the membrane material, so that the reliability and the yield of a package structure product can be effectively improved, and the cost is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of filter module packaging technology, specifically relating to a filter module packaging structure containing SMD devices. Background Technology

[0002] Filter modules are a crucial component of the RF front-end, integrating various parts. Based on the functional requirements and physical characteristics of different components within the module, some parts require bottom encapsulation, such as surface acoustic wave (SAW) filter chips. Due to product performance and design requirements, it's essential to ensure that the functional areas of the filter chip cannot come into contact with any material; this necessitates a cavity structure design. The bottom of the filter chip is not filled with plastic, thus creating a cavity to achieve the filtering function. In some packaging designs, certain passive components (SOI chips, SMD devices) require bottom encapsulation to provide better protection and stability.

[0003] However, during the molding process, the insulating film is adhered to the surface of the entire assembled substrate to physically isolate the filter chip from the molding compound, ensuring that the bottom of the filter chip is not filled with molding compound to form a cavity for filtering. But at the same time, because the film covers the entire substrate surface, other components or chips cannot be filled with molding compound. This can lead to problems such as solder flow at the solder joints under special conditions, or internal gas expansion during multiple high-temperature processes causing the product to burst or break, thus affecting the reliability of the entire filter module and ultimately causing product quality issues. Summary of the Invention

[0004] To solve the above problems, this utility model changes the position layout design of the chip and passive components. It uses the spacing to reduce the toughness of the film material so that the bottom of the specific chip and passive components is filled with molding compound, and ensures that the filter chip position is covered by the film material, and isolates the molding compound to form a bottom cavity.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0006] A filter module packaging structure containing SMD devices includes,

[0007] substrate;

[0008] The filter module disposed on the substrate includes a plurality of filter chips and a plurality of non-filter chips. The non-filter chips include SOI chips and SMD devices mounted around the SOI chips. The mounting distance between the SMD devices and the SOI chips is less than a preset threshold.

[0009] An isolation film is disposed on the upper surface of the substrate and the filter module, and a fragile film area is formed on the isolation film corresponding to the gap position between the SMD device and the SOI chip.

[0010] And a molding compound that encapsulates the substrate and the filter module.

[0011] Furthermore, the preset threshold is 120µm.

[0012] Furthermore, the substrate includes a packaged wafer or a PCB printed circuit board.

[0013] Furthermore, the material of the molding compound includes epoxy molding compound and / or ceramic material.

[0014] Furthermore, the separator is an electrically insulating film, and the material of the separator includes an aluminum nitride film and / or a scandium-doped aluminum nitride film.

[0015] Furthermore, the thickness of the isolation membrane is 10-50 micrometers.

[0016] Furthermore, the isolation membrane is applied to the filter module and the substrate by vacuum airbag pressing.

[0017] The beneficial effects of this utility model are:

[0018] This invention modifies the layout of passive components in the filter module. When the spacing between passive components in the isolation membrane is small, local stress concentration becomes more pronounced. This stress concentration can cause the material to fail under low stress, thereby reducing the overall toughness.

[0019] This solution utilizes spacing to reduce the toughness of the insulating membrane material, thereby meeting the requirements for filling the bottom of specific chips and passive components (non-filter chips) with molding compound, while ensuring that the filter chip area is covered by the membrane material, thus preventing the molding compound from forming a bottom cavity. This solution is simple to implement and can effectively improve the reliability and yield of filter module packaging structures, while reducing costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram showing the relative positions of non-filter chips in a filter module containing SMD devices, as provided in this embodiment.

[0021] Figure 2 This is a schematic diagram of the coating of a filter module containing SMD devices provided in this embodiment;

[0022] Figure 3 This is a top view of the filter module package structure containing SMD devices provided in this embodiment;

[0023] Figure 4for Figure 3 A schematic diagram of the cross-section obtained by cutting along line AA in the middle;

[0024] Figure 5 for Figure 4 A magnified view of a section at point I;

[0025] Figure 6 for Figure 4 Enlarged view of section II in the middle;

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Substrate; 2-Filter chip; 3-SOI chip; 4-SMD component; 5-Isolation film; 6-Fragile film area; 7-Encapsulation. Detailed Implementation

[0028] To further understand this utility model, preferred embodiments of this utility model are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of this utility model, and not for limiting the scope of the claims of this utility model.

[0029] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show components related to this utility model and are not drawn according to the actual number, shape, and size of the components in the actual implementation. In the actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. To keep the illustrations as concise as possible, not all structures are shown in the drawings.

[0030] The present invention will now be further described in conjunction with specific embodiments.

[0031] Specifically, see Figures 1-6 This embodiment provides a filter module packaging structure containing SMD devices, including,

[0032] substrate1;

[0033] The filter module disposed on the substrate 1 includes a plurality of filter chips 2 and a plurality of non-filter chips. The non-filter chips include SOI chips 3 and SMD devices 4 mounted around the SOI chips 3. The mounting distance between the SMD devices 4 and the SOI chips 3 is less than a preset threshold. The preset threshold is 120um.

[0034] The isolation film 5 is disposed on the upper surface of the substrate 1 and the filter module. Furthermore, a fragile film area 6 is formed on the isolation film 5 at the position between the SOI chip 3 and the SMD device 4.

[0035] And a molding compound 7, which encapsulates the substrate 1 and the filter module.

[0036] Specifically:

[0037] The substrate 1 includes a packaged wafer or a PCB (printed circuit board). The choice between a packaged wafer and a PCB depends on specific application requirements, cost considerations, and the designer's performance requirements. Packaged wafers offer higher integration and better electrical performance, while PCBs offer greater flexibility and easier manufacturing processes.

[0038] The non-filter chip includes several SOI chips 3 and several SMD devices 4; among them, SMD (Surface-Mounted Device) devices are surface-mount devices that are mounted on the PCB using surface mount technology (SMT); SOI (Silicon-On-Insulator) chips are semiconductor chips that use silicon-on-insulator technology.

[0039] The isolation film 5 is an electrically insulating film with a thickness of 10-50 micrometers. The material used to make the isolation film includes aluminum nitride film and / or scandium-doped aluminum nitride film. The isolation film is attached to the filter chip and non-filter chip by vacuum air-bag pressing. A cavity is formed between the isolation film 5, the filter chip 2, and the substrate 1.

[0040] The distance between the SOI chip 3 and SMD device 4 in the filter module is no greater than 120µm, which is the preset threshold. The formation of the fragile membrane area 6 is due to the following reasons: When the spacing between passive components in the isolation membrane is small, the local stress concentration phenomenon becomes more obvious. This stress concentration can cause the material to break under low stress, thereby reducing the overall toughness. In addition, once a crack occurs in the isolation membrane with a small spacing, the crack is more likely to propagate due to the increased stress concentration and local deformation, which correspondingly reduces the fracture toughness of the material. Under the molding pressure of the next process, the weak membrane will directly break, forming a fracture. Therefore, the spacing is used to reduce the toughness of the isolation membrane to achieve the bottom filling of the molding compound for specific chips and passive components, and to ensure that the filter chip 2 is covered by the membrane, isolating the molding compound to form a bottom cavity. See details. Figures 4-6 .

[0041] The molding compound 7 acts as a protective shield to prevent physical damage and environmental factors. The materials used to make the molding compound 7 include epoxy molding compound and / or ceramic materials. During the molding process, the molding compound material fills the gaps between the bottom of the SOI chip 3 and SMD device 4 and the substrate 1 through the cracks in the fragile film area 6, providing additional mechanical support and thermal stress buffering, thereby improving product reliability and yield.

[0042] Correspondingly, the method for fabricating the filter module packaging structure containing SMD devices in this embodiment includes,

[0043] Prepare substrate 1, and mount filter chip 2, SOI chip 3, and SMD device 4 on substrate 1 according to the design scheme. Specifically, depending on the mounting position of SOI chip 3, when SMD device 4 is present in the filter module, SMD device 4 is arranged at the edge position of one side of SOI chip 3, with the spacing maintaining the minimum mounting requirements of the process, which is 60um in this embodiment. Figure 1 This is a rendering of the completed patch installation.

[0044] A coating process is performed, in which the isolation film 5 is applied to the substrate 1 on which each chip and component has been mounted, to obtain the coated product.

[0045] During the molding process, the small gap between the SOI chip 3 and other passive components (SMD devices 4) causes the isolation membrane 5 to be stretched and weakened. During molding, the molding pressure breaks through the interface between the SOI chip and other passive components, and the molding compound enters the bottom of the SOI chip 3 and SMD devices 4 from the broken membrane, thus filling the bottom of the SOI chip 3 and SMD devices 4.

[0046] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A filter module packaging structure containing SMD devices, characterized in that, include, substrate(1); The filter module disposed on the substrate includes a plurality of filter chips (2) and a plurality of non-filter chips. The non-filter chips include SOI chips (3) and SMD devices (4) mounted around the SOI chips. The mounting distance between the SMD devices and the SOI chips is less than a preset threshold. An isolation film (5) is disposed on the upper surface of the substrate and the filter module, and a fragile film area (6) is formed on the isolation film corresponding to the gap between the SMD device and the SOI chip. and a molding compound (7), which encapsulates the substrate and the filter module.

2. The filter module packaging structure with SMD devices according to claim 1, characterized in that, The preset threshold is 120µm.

3. The filter module packaging structure with SMD devices according to claim 1, characterized in that, The substrate includes a packaged wafer or a PCB printed circuit board.

4. The filter module packaging structure with SMD devices according to claim 1, characterized in that, The thickness of the isolation membrane is 10-50 micrometers.

5. The filter module packaging structure with SMD devices according to claim 1, characterized in that, The isolation membrane is applied to the filter module and the substrate by vacuum air pressure.

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