Surface acoustic wave filter module packaging structure, and packaging method for structure

Abstract

Provided in the present invention are a surface acoustic wave filter module packaging structure, and a packaging method for the structure. The surface acoustic wave filter module packaging structure comprises a substrate, a surface acoustic wave filter chip and a non-filter chip which are disposed on the substrate, a dry film layer covering the surface acoustic wave filter chip and the non-filter chip, and a plastic packaging layer covering the dry film layer, wherein the surface acoustic wave filter chip is fixed to the substrate by means of first bump structures; a cavity is formed between the surface acoustic wave filter chip and the substrate; the non-filter chip is fixed to the substrate by means of second bump structures; the dry film layer has a fracture area surrounding the non-filter chip; and the plastic packaging layer is filled between the substrate and the non-filter chip via the fracture area. The surface acoustic wave filter module packaging structure and the method of the present invention can ensure that a cavity can be formed between the bottom of the surface acoustic wave filter chip and the substrate, and bumps do not break easily; moreover, an injection molding process of a filter based on wafer-level packaging is avoided, thereby reducing the cost and damage to the chip in a reliability stage.

Description

SAW filter module packaging structure and packaging method thereof Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to a multi-chip module packaging structure. Background Art

[0002] The operating principle of surface acoustic wave filters is the transmission of sound waves on the chip surface. Therefore, the packaging of the surface acoustic wave filter must ensure that there is sufficient cavity on the surface of the interdigital transducer (the working sensor of the surface acoustic wave filter), otherwise the product will not transmit any signal. Currently, conventional filter RF modules on the market use an injection molding solution based on wafer-level packaging of filters. Before the module is packaged, the filter wafer is first wafer-level packaged to form a cavity on the surface of each filter. The filter is then mounted on the RF module substrate and finally injection molded, marked and cut to complete the packaging. Technical issues

[0003] However, in the existing technology, the packaging solution for filter modules based on wafer-level packaging is relatively expensive, and the injection pressure is too high, which will bring reliability risks such as chip bump extrusion deformation and cracking. In addition, when using compression molding (C-Molding), the plastic packaging structure easily causes cavities to form on the surface of the plastic packaging layer, resulting in structural instability.

[0004] Therefore, it is necessary to provide a new SAW filter module packaging structure and packaging method to solve the above technical problems. Technical Solutions

[0005] The object of the present invention is to provide a surface acoustic wave filter module packaging structure, which can ensure that a cavity can be formed between the bottom of the surface acoustic wave filter chip and the substrate, while the bumps are not easy to break and have high reliability.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a surface acoustic filter module packaging structure, which includes a substrate, at least one surface acoustic filter chip arranged on the substrate, at least one non-filter chip arranged on the substrate and spaced apart from the surface acoustic filter chip, a dry film layer covering the surface acoustic filter chip and the non-filter chip, and a plastic sealing layer covering the dry film layer, the surface of the surface acoustic filter chip is fixed to the substrate through a first bump structure, and a cavity is formed between the surface acoustic filter chip and the substrate, the surface of the non-filter chip is fixed to the substrate through a second bump structure, the dry film layer is provided with a fracture area surrounding the non-filter chip, and the plastic sealing layer is filled between the substrate and the non-filter chip through the fracture area.

[0007] Preferably, the dry film layer is adhered to the surface acoustic wave filter chip and the non-filter chip by vacuum air bag lamination.

[0008] Preferably, the height of the second bump structure is not less than 50 microns.

[0009] Preferably, the height of the first bump structure is not higher than 40 microns.

[0010] Preferably, the dry film layer is an epoxy resin material.

[0011] Preferably, the thickness of the dry film layer is 40-50 microns.

[0012] Preferably, the diameter of the first bump structure is 180-200 microns, and / or the diameter of the second bump structure is 180-200 microns.

[0013] Preferably, a solder resist layer is provided between the substrate and the dry film layer, and a solder resist layer is also provided at a position in the cavity where the first bump structure is not provided.

[0014] Compared with related technologies, the surface acoustic filter module packaging structure provided by the present invention includes a substrate, at least one surface acoustic filter chip arranged on the substrate, at least one non-filter chip arranged on the substrate and spaced apart from the surface acoustic filter chip, a dry film layer covering the surface acoustic filter chip and the non-filter chip, and a plastic encapsulation layer covering the dry film layer. The surface of the surface acoustic filter chip is fixed to the substrate via a first bump structure, and a cavity is formed between the surface acoustic filter chip and the substrate. The surface of the non-filter chip is fixed to the substrate via a second bump structure. The dry film layer is provided with a fracture area surrounding the non-filter chip, and the plastic encapsulation layer is filled between the substrate and the non-filter chip through the fracture area. The surface acoustic filter module packaging structure of the present invention can ensure that a cavity can be formed between the bottom of the surface acoustic filter chip and the substrate, avoiding the use of an injection molding process for filters based on wafer-level packaging, reducing costs and damage to the chip during the reliability stage. At the same time, the bump structure is not easy to break, thereby improving the stability of the structure.

[0015] Another object of the present invention is to provide a packaging method for a surface acoustic wave filter module packaging structure, wherein the structure formed by the method can ensure that a cavity can be formed between the bottom of the surface acoustic wave filter chip and the substrate, while the bumps are not easily broken and have high reliability.

[0016] In order to achieve the above object, the technical solution of the present invention is as follows: A packaging method for a surface acoustic wave filter module packaging structure, comprising:

[0017] providing a substrate;

[0018] Providing at least one surface acoustic wave filter chip and at least one non-filter chip, wherein a surface of the surface acoustic wave filter chip is provided with a first bump structure, and a surface of the non-filter chip is provided with a second bump structure;

[0019] Flipping the surface acoustic wave filter chip and the non-filter chip and soldering them to the surface of the substrate through surface mounting technology to form a cavity between the surface acoustic wave filter chip and the substrate;

[0020] Providing a dry film layer, wherein the dry film layer covers the surface acoustic wave filter chip and the non-filter chip by vacuum air bag lamination;

[0021] Increasing the pressure of the vacuum air bag pressing the film so that only the dry film layer not surrounding the filter chip is broken to form a fracture area;

[0022] Providing a plastic sealing layer, wherein the plastic sealing layer is injection-molded to cover the dry film layer, and the plastic sealing layer is filled between the substrate and the non-filter chip through the fracture area;

[0023] The individual surface acoustic wave filter module packaging structures are formed by cutting, and each individual surface acoustic wave filter module packaging structure includes the surface acoustic wave filter chip and the non-filter chip.

[0024] Preferably, the packaging method further comprises covering the substrate with a solder resist layer when providing the substrate. Beneficial effects

[0025] Compared with the related art, the packaging method of the surface acoustic wave filter module packaging structure provided by the present invention includes providing a substrate; providing at least one surface acoustic wave filter chip and at least one non-filter chip, the surface of the surface acoustic wave filter chip is provided with a first bump structure, and the surface of the non-filter chip is provided with a second bump structure; flipping the surface acoustic wave filter chip and the non-filter chip and soldering them to the surface of the substrate through surface mounting technology to form a cavity between the surface acoustic wave filter chip and the substrate; providing a dry film layer, the dry film layer covering the surface acoustic wave filter chip and the non-filter chip by vacuum air bag pressing; increasing the pressure of the vacuum air bag pressing so that only the dry film layer around the non-filter chip is broken to form a fracture area; providing a plastic sealing layer, the plastic sealing layer injection-molded to cover the dry film layer, and the plastic sealing layer is filled between the substrate and the non-filter chip through the fracture area; cutting to form a single surface acoustic wave filter module packaging structure, each single surface acoustic wave filter module packaging structure includes one surface acoustic wave filter chip and one non-filter chip. The surface acoustic wave filter module packaging structure formed by the packaging method of the present invention can ensure that a cavity can be formed between the bottom of the surface acoustic wave filter chip and the substrate, avoiding the use of an injection molding process based on a wafer-level packaging filter, reducing costs and damage to the chip during the reliability stage. At the same time, the bump structure is not easy to break, thereby improving the stability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a flow chart of a method for preparing a surface acoustic wave filter module packaging structure according to the present invention;

[0027] 2a to 2f are schematic diagrams of the manufacturing process of the surface acoustic wave filter module packaging structure of the present invention. Best Mode for Carrying Out the Invention

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Referring to FIG. 2f , the present invention provides a surface acoustic wave filter (SAF) module packaging structure 100. The SAF module packaging structure 100 includes a substrate 1, at least one SAF chip 2 disposed on the substrate 1, at least one non-filter chip 3 disposed on the substrate 1 and spaced apart from the SAF chip 2, a dry film layer 4 covering the SAF chip 2 and the non-filter chip 3, a solder resist layer 5 disposed between the substrate 1 and the dry film layer 4, and a plastic encapsulation layer 6 covering the dry film layer 4. The surface of the SAF chip 2 is secured to the surface of the substrate 1 via a first bump structure 71, forming a cavity 20 between the SAF chip 2 and the substrate 1. The surface of the non-filter chip 3 is secured to the surface of the substrate 1 via a second bump structure 72.

[0030] Please refer to Figure 2e. The dry film layer 4 is attached to the surface acoustic wave filter chip 2 and the non-filter chip 3 by vacuum air bag lamination. The dry film layer 4 can prevent other substances from flowing between the surface acoustic wave filter chip 2 and the substrate 1, ensuring that the cavity 20 can be formed between the surface acoustic wave filter chip 2 and the substrate 1. The dry film layer 4 has a fracture area 41 surrounding the non-filter chip 3. The dry film layer 4 is made of epoxy resin material and has a thickness of 40-50 microns.

[0031] The solder resist layer 5 is arranged on the surface of the substrate 1, and the solder resist layer 5 is also provided at the position in the cavity 20 where the first bump structure 71 is not provided. In this way, the first bump structures 71 will not be soldered to each other and other circuits on the substrate 1, thereby preventing a short circuit from occurring.

[0032] The first and second bump structures 71, 72 are both solder balls. The diameter of the first and second bump structures 71 is 180-200 microns, and / or the diameter of the second bump structures 72 is 180-200 microns. The height of the first and second bump structures 71 is no higher than 40 microns, and the height of the second bump structures 72 is no lower than 50 microns. The height restrictions of the first and second bump structures 71, 72 ensure that when the vacuum bag pressure is increased, only the dry film layer 4 surrounding the non-filter chip 3 will crack, forming the fracture area 41, while the dry film layer 4 surrounding the filter chip 2 will not crack.

[0033] The plastic encapsulation layer 6 covers the dry film layer 4 through a compression molding process (C-Molding) to complete the plastic encapsulation. The plastic encapsulation layer 6 fills the gap between the substrate 1 and the non-filter chip 3 through the fracture area 41. The plastic encapsulation layer 6 in this area can support the second bump structure 72 and prevent stress from causing the second bump structure 72 to crack. The plastic encapsulation layer 6 is made of epoxy resin, and the material composition ratio of the epoxy resin forming the plastic encapsulation layer 6 is different from the material composition ratio of the epoxy resin forming the dry film layer 4.

[0034] Please refer to FIG. 1-2 f at the same time. The packaging method of the surface acoustic wave filter module packaging structure 100 is as follows, specifically including:

[0035] S1: providing a substrate 1;

[0036] S2: providing a solder resist layer 5, covering the substrate 1 with a solder resist layer 5, removing a portion of the solder resist layer 5 to make way for the chip;

[0037] S3: Providing at least one surface acoustic wave filter chip 2 and at least one non-filter chip 3, wherein a first bump structure 71 is provided on the surface of the surface acoustic wave filter chip 2, and a second bump structure 72 is provided on the surface of the non-filter chip 3, wherein the first bump structure 71 and the second bump structure 72 are both solder balls, wherein the diameter of the first bump structure 71 is 180-200 microns, and / or the diameter of the second bump structure 72 is 180-200 microns, the height of the first bump structure 71 is not higher than 40 microns, and the height of the second bump structure 72 is not lower than 50 microns;

[0038] S4: flip-chipping the SAW filter chip 2 and the non-filter chip 3 and soldering them to the surface of the substrate 1 through surface mount technology (SMT) to form a cavity 20 between the SAW filter chip 2 and the substrate 1;

[0039] S5: providing a dry film layer 4, wherein the dry film layer 4 covers the surface acoustic wave filter chip 2 and the non-filter chip 3 by vacuum air bag lamination, wherein the dry film layer 4 is made of epoxy resin material and has a thickness of 40-50 μm;

[0040] S6: increasing the pressure of the vacuum air bag film pressing, so that only the dry film layer around the non-filter chip 3 is broken to form a fracture area, while the dry film layer around the SAW filter chip 2 is broken;

[0041] S7: Providing a plastic sealing layer 6, wherein the plastic sealing layer 6 is injection-molded to cover the dry film layer 4, and the plastic sealing layer 6 is filled between the substrate 1 and the non-filter chip 3 through the fracture area 41, and the plastic sealing layer 6 is made of epoxy resin material;

[0042] S7: cutting to form individual SAW filter module packaging structures 100 . Each individual SAW filter module packaging structure 100 includes one SAW filter chip 2 and the non-filter core 3 .

[0043] The SAW filter module packaging structure 100 formed by this packaging method can ensure that a cavity can be formed between the bottom of the SAW filter chip 2 and the substrate 1 . Meanwhile, the second bump structure 72 is not easily broken and has high reliability.

[0044] Compared with related technologies, the surface acoustic filter module packaging structure provided by the present invention includes a substrate, at least one surface acoustic filter chip arranged on the substrate, at least one non-filter chip arranged on the substrate and spaced apart from the surface acoustic filter chip, a dry film layer covering the surface acoustic filter chip and the non-filter chip, and a plastic encapsulation layer covering the dry film layer. The surface of the surface acoustic filter chip is fixed to the substrate via a first bump structure, and a cavity is formed between the surface acoustic filter chip and the substrate. The surface of the non-filter chip is fixed to the substrate via a second bump structure. The dry film layer is provided with a fracture area surrounding the non-filter chip, and the plastic encapsulation layer is filled between the substrate and the non-filter chip through the fracture area. The surface acoustic filter module packaging structure of the present invention can ensure that a cavity can be formed between the bottom of the surface acoustic filter chip and the substrate, avoiding the use of an injection molding process for filters based on wafer-level packaging, reducing costs and damage to the chip during the reliability stage. At the same time, the bump structure is not easy to break, thereby improving the stability of the structure.

[0045] Compared with the related art, the packaging method of the surface acoustic wave filter module packaging structure provided by the present invention includes providing a substrate; providing at least one surface acoustic wave filter chip and at least one non-filter chip, the surface of the surface acoustic wave filter chip is provided with a first bump structure, and the surface of the non-filter chip is provided with a second bump structure; flipping the surface acoustic wave filter chip and the non-filter chip and soldering them to the surface of the substrate through surface mounting technology to form a cavity between the surface acoustic wave filter chip and the substrate; providing a dry film layer, the dry film layer covering the surface acoustic wave filter chip and the non-filter chip by vacuum air bag pressing; increasing the pressure of the vacuum air bag pressing so that only the dry film layer around the non-filter chip is broken to form a fracture area; providing a plastic sealing layer, the plastic sealing layer injection-molded to cover the dry film layer, and the plastic sealing layer is filled between the substrate and the non-filter chip through the fracture area; cutting to form a single surface acoustic wave filter module packaging structure, each single surface acoustic wave filter module packaging structure includes one surface acoustic wave filter chip and one non-filter chip. The surface acoustic wave filter module packaging structure formed by the packaging method of the present invention can ensure that a cavity can be formed between the bottom of the surface acoustic wave filter chip and the substrate, avoiding the use of an injection molding process based on a wafer-level packaging filter, reducing costs and damage to the chip during the reliability stage. At the same time, the bump structure is not easy to break, thereby improving the stability of the structure.

[0046] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A surface acoustic wave filter module packaging structure, characterized in that: The surface acoustic wave filter module packaging structure includes a substrate, at least one surface acoustic wave filter chip arranged on the substrate, at least one non-filter chip arranged on the substrate and spaced apart from the surface acoustic wave filter chip, a dry film layer covering the surface acoustic wave filter chip and the non-filter chip, and a plastic packaging layer covering the dry film layer. The surface of the surface acoustic wave filter chip is fixed to the substrate through a first bump structure, and a cavity is formed between the surface acoustic wave filter chip and the substrate. The surface of the non-filter chip is fixed to the substrate through a second bump structure. The dry film layer is provided with a fracture area surrounding the non-filter chip, and the plastic packaging layer is filled between the substrate and the non-filter chip through the fracture area.

2. The surface acoustic wave filter module packaging structure according to claim 1, wherein: The dry film layer is adhered to the surface acoustic wave filter chip and the non-filter chip by vacuum air bag lamination.

3. The surface acoustic wave filter module packaging structure according to claim 2, wherein: The height of the second bump structure is not less than 50 microns.

4. The surface acoustic wave filter module packaging structure according to claim 2, wherein: The height of the first bump structure is no greater than 40 micrometers.

5. The surface acoustic wave filter module packaging structure according to claim 2, wherein: The dry film layer is made of epoxy resin material.

6. The surface acoustic wave filter module packaging structure according to claim 2, characterized in that: The thickness of the dry film layer is 40-50 microns.

7. The surface acoustic wave filter module packaging structure according to claim 1, wherein: The diameter of the first bump structure is 180-200 microns, and / or the diameter of the second bump structure is 180-200 microns.

8. The surface acoustic wave filter module packaging structure according to claim 1, wherein: A solder resist layer is provided between the substrate and the dry film layer, and a solder resist layer is also provided at a position in the cavity where the first bump structure is not provided.

9. A packaging method for a surface acoustic wave filter module packaging structure, characterized in that: The packaging method comprises: providing a substrate; Providing at least one surface acoustic wave filter chip and at least one non-filter chip, wherein a surface of the surface acoustic wave filter chip is provided with a first bump structure, and a surface of the non-filter chip is provided with a second bump structure; Flipping the surface acoustic wave filter chip and the non-filter chip and soldering them to the surface of the substrate through surface mounting technology to form a cavity between the surface acoustic wave filter chip and the substrate; Providing a dry film layer, wherein the dry film layer covers the surface acoustic wave filter chip and the non-filter chip by vacuum air bag lamination; Increasing the pressure of the vacuum air bag pressing the film so that only the dry film layer not surrounding the filter chip is broken to form a fracture area; Providing a plastic sealing layer, wherein the plastic sealing layer is injection-molded to cover the dry film layer, and the plastic sealing layer is filled between the substrate and the non-filter chip through the fracture area; The individual surface acoustic wave filter module packaging structures are formed by cutting, and each individual surface acoustic wave filter module packaging structure includes the surface acoustic wave filter chip and the non-filter chip.

10. The packaging method of the surface acoustic wave filter module packaging structure according to claim 9, characterized in that: The packaging method further comprises covering the substrate with a solder resist layer when providing the substrate.

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