An encapsulation structure of a filter module and a manufacturing method thereof

Abstract

The present invention discloses a packaging structure of a filter module and a manufacturing method thereof. The filter module packaging structure forms a cavity between the isolation membrane and the filter chip and substrate after the isolation membrane is attached, and no cavity is formed between the isolation membrane and the filter chip and substrate after the plastic sealing. This ensures that the filter module can work normally after plastic sealing and improves reliability. The puncture part forms a sharp corner around the top of a single other functional chip after cutting by changing the shape of the cutting blade, and the sharp corner is the puncture part. The method is simple. The present invention is a new process method for mixed packaging of filter chips and other functional chips, which solves the problem that the filter module cannot fill the cavity at the bottom of other functional chips when the filter module is plastic sealed after being coated with the isolation membrane, promotes the functionalization and integration of filter products, reduces production costs, and improves economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and more particularly to a packaging structure of a filter module and a manufacturing method thereof. Background Art

[0002] Due to the demand for multi-mode, multi-band, and high-power terminals, 5G terminals have put forward a series of new requirements for RF front-end components, such as wide bandwidth, high power, low power consumption, and module miniaturization. Currently, the mainstream development direction in the industry is to integrate RF front-end components such as filters, switches, and power amplifiers into modular products to form filter modules.

[0003] The common structure for filter module packaging involves flip-chipping the filter chip and other functional chips, such as switches and power amplifiers, onto a substrate. An isolation film is then attached above the chips. The isolation film is then filled with molding compound and the surface is smoothed, completing the entire filter module package.

[0004] In the prior art, in order for the filter chip to allow specific frequency components in the signal to pass through and greatly attenuate or filter other frequency components, a cavity environment needs to be formed at the bottom of the filter chip to ensure normal operation. However, during the isolation film coating process, other functional chips such as switches and power amplifiers will also form cavities at the bottom due to the isolation film coating. In the subsequent plastic sealing process, the plastic sealing material cannot fill the cavities at the bottom of other functional chips. When the filter module product obtained in this way is in operation, the cavities at the bottom of other functional chips will affect the reliability of the entire filter module, and ultimately cause product quality problems. Specifically, the cavities at the bottom of other functional chips are subsequently subjected to multiple high-temperature processes under incomplete vacuum conditions, and the internal gas expands, causing the product to explode and break.

[0005] Therefore, there is an urgent need for a new packaging structure of a filter module and a manufacturing method thereof. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a packaging structure of a filter module and a manufacturing method thereof, which solves the problem that the filter module cannot fill the bottom cavity of other functional chips when it is plastic-sealed after being coated with an isolation film, thereby improving the reliability of the filter module product.

[0007] In one aspect, the present invention provides a method for manufacturing a filter module packaging structure, the manufacturing method comprising at least the following steps:

[0008] S1. Providing a substrate and a filter module, wherein the filter module includes a filter chip and other functional chips, and a puncture portion is formed around the top of each of the other functional chips;

[0009] S2, flip-mounting the filter chip and other functional chips on the substrate;

[0010] S3, attaching an isolation film to the surface of the substrate, and the puncture portion of the other functional chip punctures the isolation film, so that after the isolation film is coated, a cavity is formed between the isolation film, the filter chip, and the substrate, while no cavity is formed between the isolation film and the other functional chips and the substrate;

[0011] S4. After the isolation film is coated, plastic sealing is performed.

[0012] On the other hand, the present invention provides a filter module packaging structure manufactured according to the above manufacturing method, the packaging structure comprising:

[0013] substrate;

[0014] A filter module flip-mounted on the substrate, the filter module including a filter chip and other functional chips, wherein each of the other functional chips has puncture portions around its top; the area on the substrate where the filter chip is mounted is painted green, while the area on the substrate where the other functional chips are mounted is not painted green;

[0015] An isolation membrane is provided on the upper surface of the substrate and the filter module, the puncture portion punctures the isolation membrane, a cavity is formed between the isolation membrane, the filter chip, and the substrate, and no cavity is formed between the isolation membrane and other functional chips and the substrate; and

[0016] A plastic encapsulation layer covers the substrate and the filter module.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The filter module packaging structure disclosed in the present invention provides puncture points around the top of other functional chips. After the isolation film is attached, a cavity is formed between the isolation film and the filter chip and substrate, while no cavity is formed between the isolation film and the other functional chips and substrate. This ensures that the filter module can operate normally after plastic sealing and improves reliability.

[0019] 2. A puncture portion is set around the top of the other functional chip. The present invention cleverly utilizes the process of cutting a single other functional chip from the entire first wafer. Only the shape of the cutting blade is changed so that sharp corners are formed around the top of the single other functional chip after cutting. The sharp corners are the puncture portions. The method is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the packaging process of the filter module packaging structure in the present invention;

[0021] Figure 2 Schematic diagram of the first wafer cutting;

[0022] Figure 3 for Figure 2 A schematic diagram of the structure of a single other functional chip after the first wafer is cut;

[0023] Figure 4 Schematic diagram of cutting the second wafer;

[0024] Figure 5 Schematic diagram of the filter module packaging structure. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings.

[0026] This embodiment schematically discloses a method for manufacturing a filter module packaging structure, which comprises at least the following steps:

[0027] S1. Provide a substrate 1 and a filter module. The filter module includes a filter chip 2 and other functional chips 3. A puncture portion 30 is formed around the top of each other functional chip 3.

[0028] S2, flip-chip the filter chip 2 and other functional chips 3 onto the substrate 1;

[0029] S3. Attach an isolation film 4 to the surface of the substrate 1. The piercing portion 30 of the other functional chip 3 pierces the isolation film 4. After the isolation film 4 is coated, a cavity 5 is formed between the isolation film 4, the filter chip 2, and the substrate 1. No cavity 5 is formed between the isolation film 4 and the other functional chip 3 and the substrate 1.

[0030] S4, after the isolation film 4 is coated, plastic sealing is performed.

[0031] Figure 1 The schematic diagram of the packaging process of the filter module packaging structure in this embodiment is disclosed schematically. In step S1, the substrate 1 is prepared first, and the area on the substrate 1 where the filter chip 2 is installed is coated with green paint 6, so that the distance between the filter chip 2 installed subsequently and the surface of the green paint 6 on the substrate 1 is small, and the film is not easily broken during the plastic sealing after the film is pressed, but it is easy to be broken. If it is broken, a cavity cannot be formed at the bottom of the filter chip 2. The area where other functional chips 3 are installed on the substrate 1 is not coated with green paint 6, so that the distance between the other functional chips 3 installed subsequently and the surface of the substrate 1 is large. In step S1, the puncture portion 30 is the sharp corners around the top of a single other functional chip 3. As shown in FIG. Figure 2As shown, the single other functional chip 3 is arranged on the first wafer 8 before cutting. In the present invention, a conical blade 9 is used to cut the first wafer 8 so that a sharp corner is formed around the top of the single other functional chip 3. The sharp corner is the puncture portion 30. The structure of the single other functional chip 3 after cutting is as follows: Figure 3 As shown. In the prior art, a normal rectangular dicing blade is used to dice the entire wafer, resulting in a flat surface around the cut surface of each chip. However, this embodiment cleverly utilizes a tapered blade 9 to dice the first wafer 8. After cutting, the cut surface around each other function chip 3 forms a top-down and inwardly inclined surface, forming a sharp corner around the top of each other function chip 3, namely the puncture portion 30.

[0032] The inclination angles of the tapered blades 9 are different, and the shapes of the other functional chips 3 after cutting are also different:

[0033] 1. When the blade inclination angle of the conical blade 9 is large, the angle a formed by the cutting bevel around the other functional chip 3 after cutting and the surface of the other functional chip 3 is smaller, and the puncture portion 30 formed around the top of the other functional chip 3 is sharper; during the subsequent film pressing, the contact area between the puncture portion 30 and the isolation film 4 is smaller, and the puncture effect is better;

[0034] 2. When the inclination angle of the blade of the conical blade 9 is small, the angle a formed by the cutting bevel around the other functional chips 3 after cutting and the surface of the other functional chips 3 is large, and the puncture portion 30 formed around the top of the other functional chips 3 is small in sharpness; during subsequent film pressing, the contact area between the puncture portion 30 and the isolation film 4 is large, and the puncture effect is average.

[0035] In both cases, the technical problem of rupturing the isolation film 4 during lamination can be solved. In the first case, since the angle a formed by the cut bevel and the surface after cutting is smaller, the contact area between the puncture portion 30 and the isolation film 4 during lamination is smaller, so the puncture effect is better.

[0036] In this embodiment, the cutting edge angle of the tapered blade 9 is greater than 0 degrees and less than 180 degrees, which can solve the technical problem of puncturing and breaking the isolation film 4 during film pressing. In practical applications, after cutting, the angle formed by the cutting bevel of the tapered blade 9 and the surface is greater than 15 degrees and less than 60 degrees, the puncture effect is better.

[0037] In addition, the filter chips 2 are arranged on the second wafer 10, and the second wafer 10 is cut using a straight blade 11, as shown in FIG. Figure 4 This is prior art and will not be described in detail here.

[0038] Before dicing, the first and second wafers 8, 10 must be ground. After grinding, the thickness of the first wafer 8 is greater than that of the second wafer 10, causing the height of the other functional chips 3 to be higher than that of the filter chip 2. This height difference between the filter chip 2 and the other functional chips 3 makes it easier for the plastic encapsulation compound to break through the film surrounding the taller chip during plastic encapsulation. However, this height difference should not be too large, as it can lead to premature puncture.

[0039] After completing the above method, the filter chip 2 and other functional chips 3 are flip-mounted on the substrate 1. The process of flip-mounting chips on the substrate 1 is a well-established technique and will not be described in detail here. Due to the height difference between the filter chip 2 and the other functional chips 3, the film around the other functional chips 3 is more likely to be broken during the lamination process due to vacuum and force.

[0040] However, the spacing between the filter chip 2 and the other functional chips 3 will also have an impact on the film breaking. The smaller the spacing, the easier it is to break the film around the other functional chips 3. The spacing between adjacent chips in the filter module should be adjusted according to the height of the chip, so that the isolation film 4 is not prematurely scratched and broken by the puncture part 30 of the other functional chip 3 before being adsorbed to the surface of the substrate 1, otherwise it will affect the effect of the film. In this embodiment, the height difference between the other functional chips 3 and the filter chip 2 is set to be greater than 0 and less than 200μm. That is, if the height of a certain other functional chip 3 is greater than 200um higher than the height of the filter chip 2, the spacing between the adjacent chips is greater than 0.6 times the thickness of the other functional chip 3; if the height of a certain other functional chip 3 is less than 200um higher than the height of the filter chip 2, the spacing between the adjacent chips is greater than 0.7 times the thickness of the other functional chip 3. When the height difference and chip spacing are met at the same time, the aforementioned problem of prematurely scratching the isolation film 4 can be solved. The chip spacing in this embodiment refers to the distance between the right end of the left chip and the left end of the right chip.

[0041] The substrate 1 of step S2 is placed on the film laminating platform, and an isolation film 4 is attached to the surface of the substrate 1, i.e., step S3. The isolation film 4 is a white film. The isolation film 4 is laminated through the vacuum chamber 5 of the laminating machine. By adjusting appropriate laminating parameters, the isolation film 4 is punctured and broken by the height difference between the other functional chips and the surface of the substrate 1 and the action of the puncture portion 30. After the isolation film 4 is laminated, a cavity 5 is formed between the isolation film 4 and the filter chip 2 and the substrate 1, i.e., a cavity 5 is formed at the bottom of the filter chip 2, while no cavity 5 is formed between the isolation film 4 and the other functional chips 3 and the substrate 1, i.e., no cavity 5 is formed at the bottom of the other functional chips 3.

[0042] After the isolation film 4 is coated, the step S4 of plastic encapsulation is performed. During the plastic encapsulation, there is no cavity 5 at the bottom of the other functional chips 3, which can be filled with plastic encapsulation material 7.

[0043] Finally, the plastic-sealed filter module product is cut into individual pieces to complete the packaging of the entire product.

[0044] The above manufacturing method cleverly utilizes the process of cutting a single other functional chip 3 from the entire first wafer 8. Only the shape of the cutting blade is changed so that sharp corners are formed around the top of the cut single other functional chip 3, and the sharp corner is the puncture part 30. The method is simple.

[0045] The filter module packaging structure manufactured according to the above method is as follows Figure 5 As shown, the packaging structure includes:

[0046] substrate1;

[0047] A filter module flip-mounted on a substrate 1 includes a filter chip 2 and other functional chips 3. A single other functional chip 3 has puncture marks 30 around its top. The area on the substrate 1 where the filter chip 2 is mounted is coated with green paint 6, while the area on the substrate 1 where the other functional chips 3 are mounted is not coated with green paint 6.

[0048] An isolation film 4 is provided on the upper surface of the substrate 1 and the filter module, and the piercing portion 30 pierces the isolation film 4, forming a cavity 5 between the isolation film 4, the filter chip 2, and the substrate 1, while no cavity 5 is formed between the isolation film 4 and the other functional chips 3 and the substrate 1; and

[0049] The plastic encapsulation layer covers the substrate 1 , the filter module and the isolation film 4 , and the plastic encapsulation layer is the plastic encapsulation material 7 .

[0050] The above-mentioned filter module packaging structure sets puncture parts 30 around the top of other functional chips 3. After attaching the isolation film 4, a cavity 5 is formed between the isolation film 4 layer and the filter chip 2 and substrate 1, and no cavity 5 is formed between the other functional chips 3 and substrate 1, so as to ensure that in the filter module packaging structure after plastic sealing, there is no cavity 5 at the bottom of other functional chips 3, so that the packaging structure can work stably and normally, thereby improving product reliability and yield.

[0051] The packaging structure and manufacturing method of the filter module disclosed in the present invention is a new process method for mixed packaging of the filter chip 2 and other functional chips, which promotes the functionalization and integration of filter products, reduces production costs and improves economic benefits.

[0052] The above are only some embodiments of the present invention. It should be pointed out that for ordinary technicians in this field, other variations and improvements can be made without departing from the creative concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a filter module packaging structure, characterized in that: The manufacturing method comprises at least the following steps: S1. Providing a substrate and a filter module, wherein the filter module includes a filter chip and other functional chips, and a puncture portion is formed around the top of each of the other functional chips; S2, flip-mounting the filter chip and other functional chips on the substrate; S3, attaching an isolation film to the surface of the substrate, and the puncture portion of the other functional chip punctures the isolation film, so that after the isolation film is coated, a cavity is formed between the isolation film, the filter chip, and the substrate, while no cavity is formed between the isolation film and the other functional chips and the substrate; S4. After the isolation film is coated, plastic sealing is performed; Among them, the puncture part of other functional chips is made according to the following method: The single other functional chips are arranged on the first wafer before cutting, and the first wafer is cut using a conical blade. The cutting surface around the single other functional chip after cutting is a slope from top to bottom and inward, so that sharp corners are formed around the top of the single other functional chip, namely the puncture part.

2. The method for manufacturing the filter module packaging structure according to claim 1, wherein: In the step S1 , the area on the substrate where the filter chip is mounted is coated with green paint, and the area on the substrate where other functional chips are mounted is not coated with green paint.

3. The method for manufacturing the filter module packaging structure according to claim 2, wherein: The blade angle of the tapered blade is greater than 0 degree and less than 180 degrees.

4. The method for manufacturing the filter module packaging structure according to claim 3, wherein: The filter chips are arranged on a second wafer, and the second wafer is cut using a straight blade.

5. The method for manufacturing the filter module packaging structure according to claim 4, wherein: The first wafer and the second wafer need to be ground before being cut, and the thickness of the first wafer is greater than the thickness of the second wafer.

6. The method for manufacturing the filter module packaging structure according to claim 5, wherein: The distance between adjacent chips in the filter module is adjusted according to the height of the chips, so that the isolation film is not scratched in advance by the puncture parts of other functional chips before being adsorbed onto the surface of the substrate.

7. The method for manufacturing the filter module packaging structure according to claim 6, wherein: In the step S4: during the plastic packaging, the bottom of the other functional chips is filled with plastic packaging material.

8. A packaging structure of a filter module, characterized in that: include: substrate; A filter module flip-mounted on the substrate, the filter module including a filter chip and other functional chips, wherein each of the other functional chips has puncture portions around its top; the area on the substrate where the filter chip is mounted is painted green, while the area on the substrate where the other functional chips are mounted is not painted green; An isolation membrane is arranged on the upper surface of the substrate and the filter module, the puncture portion punctures the isolation membrane, a cavity is formed between the isolation membrane and the filter chip and the substrate, and no cavity is formed between the isolation membrane and other functional chips and the substrate; and a plastic encapsulation layer, the plastic encapsulation layer covers the substrate and the filter module.

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