Filter packaging structure and manufacturing method

Abstract

The present invention discloses a filter packaging structure and manufacturing method. The filter packaging structure includes a chip, a substrate, and an annular retaining wall. The annular retaining wall is disposed below the chip, and the substrate is provided with an annular groove that cooperates with the annular retaining wall. The chip is soldered to the substrate via solder balls, and the annular retaining wall is embedded in the annular groove so that a cavity is formed between the chip, the substrate, and the annular retaining wall, and the bottom of the annular retaining wall does not contact the bottom surface of the annular groove. By providing the annular retaining wall on the chip and the mutually cooperating annular groove on the substrate, the annular retaining wall can be embedded in the annular groove of the substrate after the chip is mounted to form a cavity. This effectively prevents material from a protective film layer that overflows during lamination of the chip and substrate from entering the cavity and contaminating the solder balls and the effective area of ​​the chip, thereby improving the reliability of the cavity.

Description

Technical Field

[0001] The present invention relates to the field of packaging technology, and in particular to a filter packaging structure and a manufacturing method. Background Art

[0002] In the prior art, when packaging filter chips, the following problem always exists: when packaging the chip and substrate, during the process of pressing the chip and substrate together through the epoxy film, the resin in the epoxy film will directly flow into the cavity at the bottom of the chip, contaminating the gold / solder bumps and effective areas on the chip surface, thereby reducing the performance of the filter product. Summary of the Invention

[0003] The present invention aims to address the shortcomings of the prior art and provides a filter packaging structure and a manufacturing method.

[0004] In order to solve the above technical problems, the present invention is solved by the following technical solutions:

[0005] A filter packaging structure includes a chip, a substrate and an annular retaining wall;

[0006] The annular retaining wall is arranged on the front of the chip, and the surface of the substrate is provided with an annular groove that cooperates with the annular retaining wall;

[0007] The chip is soldered to the substrate via solder balls, and the annular retaining wall is embedded in the annular groove so that a cavity is formed between the chip, the substrate and the annular retaining wall, and the bottom of the annular retaining wall does not contact the bottom surface of the annular groove.

[0008] As an embodiment, it further includes a protective film layer;

[0009] The protective film layer includes at least a first protection zone and a second protection zone, wherein the first protection zone covers the back and side surfaces of the chip and the substrate outside the cavity, and the second protection zone is arranged outside the annular retaining wall and inside the annular groove.

[0010] As an implementation method, there is at least one solder ball located inside the cavity.

[0011] As an implementable embodiment, the height of the annular retaining wall is not less than the height of the solder ball finally formed by welding, so that the communication area between the cavity and the outside is a U-shaped channel.

[0012] As an implementation method, the height of the annular retaining wall is not greater than the height of the initially formed solder ball, the depth of the annular groove is greater than half the height of the initially formed solder ball, and the width of the annular groove is not less than the thickness of the annular retaining wall.

[0013] As an implementable embodiment, the material of the annular retaining wall is PI material.

[0014] A method for manufacturing a filter packaging structure comprises the following steps:

[0015] Providing a chip, and setting an annular retaining wall on the front of the chip;

[0016] welding solder balls on the front side of the chip and inside the annular retaining wall;

[0017] Providing a base plate, wherein the base plate is provided with an annular groove that cooperates with the annular retaining wall;

[0018] The chip is soldered to the substrate via solder balls, and the annular retaining wall is embedded in the annular groove so that a cavity is formed between the chip, the substrate and the annular retaining wall, and the bottom of the annular retaining wall does not contact the bottom surface of the annular groove.

[0019] As an implementable method, the following steps are also included:

[0020] Filling a protective film layer on the surface of the substrate and the chip;

[0021] The protective film layer has at least a first protection zone and a second protection zone, wherein the first protection zone covers the back and side surfaces of the chip and the top of the substrate outside the cavity, and the second protection zone is arranged outside the annular retaining wall and in the annular groove.

[0022] As an implementation method, there is at least one solder ball located inside the cavity.

[0023] As an implementation method, the height of the annular retaining wall is not less than the height of the solder ball finally formed by welding, so that the communication area between the cavity and the outside is a U-shaped channel;

[0024] The height of the annular retaining wall is not greater than the height of the initially formed solder ball, the depth of the annular groove is greater than half the height of the initially formed solder ball, and the width of the annular groove is not less than the thickness of the annular retaining wall.

[0025] As an implementable embodiment, the material of the annular retaining wall is PI material.

[0026] The present invention has significant technical effects due to the adoption of the above technical solutions:

[0027] In the present invention, an annular retaining wall is provided on the front surface of the chip, and an annular groove that cooperates with each other is provided on the surface of the substrate. This allows the annular retaining wall to be embedded in the annular groove of the substrate after chip mounting to form a cavity. This effectively prevents material from the protective film layer that overflows during lamination of the chip and substrate from entering the cavity and contaminating the solder balls and the effective area of ​​the chip, thereby improving the reliability of the chip cavity structure. Furthermore, since the height of the solder balls varies during the soldering process, if both the solder balls and the annular retaining wall are directly soldered to the substrate, the size of the solder balls will change while the height of the annular retaining wall will remain unchanged, potentially leading to poor electrical contact between the chip and the substrate and affecting electrical performance. Furthermore, if both the solder balls and the annular retaining wall are soldered, process errors in the solder ball height and the annular retaining wall may result in a gap between the annular retaining wall and the substrate, potentially contaminating the cavity. In the present invention, an annular groove that cooperates with the annular retaining wall is provided on the substrate. During packaging, the annular retaining wall does not need to be soldered to the substrate, but only needs to be embedded in the annular groove of the substrate. Subsequently, when the protective film layer material is filled, it can be fully filled and will not flow into the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 1 is a schematic diagram of the overall structure of the filter packaging structure according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic structural diagram of a front structure of a chip provided with an annular retaining wall in an embodiment of the present invention;

[0031] Figure 3 Schematic diagram of the structure of solder balls on a chip according to an embodiment of the present invention;

[0032] Figure 4 1 is a schematic structural diagram of a substrate provided with an annular groove in an embodiment of the present invention;

[0033] Figure 5 It is a schematic structural diagram of bonding a chip to a substrate via solder balls in an embodiment of the present invention.

[0034] Description of the reference numerals in the accompanying drawings:

[0035] 1. Chip; 2. Annular retaining wall; 3. Solder ball; 4. Substrate; 41. Annular groove; 5. Protective film layer; 6. Cavity; 7. First protection zone; 8. Second protection zone. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to the examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0037] Example 1:

[0038] A filter packaging structure, such as Figure 1 As shown, it includes a chip 1, a substrate 4 and an annular retaining wall 2; the annular retaining wall 2 is arranged on the front of the chip 1, and the surface of the substrate 4 is provided with an annular groove 41 that cooperates with the annular retaining wall 2; the chip 1 is welded to the substrate 4 through the solder ball 3, and the annular retaining wall 2 is embedded in the annular groove 41 so that a cavity 6 is formed between the chip 1, the substrate 4 and the annular retaining wall 2 and the bottom of the annular retaining wall 2 does not contact the bottom surface of the annular groove 41.

[0039] The present invention solves the problem that the cavity in the traditional filter packaging structure is easily filled with glue or contaminated. In order to prevent the solder balls 3 and the effective area on the front of the chip 1 from being contaminated, an annular retaining wall 2 is provided on the front of the chip 1, and mutually matching annular grooves 41 are provided on the surface of the substrate 4. After the chip is mounted, the annular retaining wall 2 can be embedded in the annular groove 41 of the substrate 4, effectively preventing the material of the protective film layer 5 that overflows when the chip 1 and the substrate 4 are pressed together from entering the cavity 6 and contaminating the solder balls 3 and the effective area on the front of the chip 1, thereby improving the reliability of the cavity 6.

[0040] In addition, since the height of the solder ball 3 will change during the welding process, if the solder ball 3 and the annular retaining wall 2 are directly welded to the substrate 4, on the one hand, the height of the solder ball 3 will change, but the height of the annular retaining wall 2 will remain unchanged, which may lead to poor electrical contact between the chip 1 and the substrate 4 and affect the electrical performance; on the other hand, if the solder ball 3 and the annular retaining wall 2 are both welded, due to the height of the solder ball 3 and the process error of the annular retaining wall 2, there may be a gap between the annular retaining wall 2 and the substrate 4, and the cavity 6 may be contaminated. The present invention provides an annular groove 41 on the surface of the substrate 4 that cooperates with the annular retaining wall 2. During packaging, the annular retaining wall 2 does not need to be welded to the substrate 4, but only needs to be embedded in the annular groove 41 of the substrate 4. When the material of the protective film layer 5 is subsequently filled, it can be fully filled and will not flow into the cavity 6.

[0041] In the present invention, the material of the annular retaining wall 2 is PI material. The material of the annular retaining wall 2 can also be a conductive material, such as copper. Copper is used as the material to form the annular retaining wall 2 on the front of the chip 1; copper plus tin can also be used as the material to form the annular retaining wall 2 on the front of the chip 1. First, an initial annular retaining wall is formed on the front of the copper material chip 1. In order to increase the height of the annular retaining wall, tin can be used as the material to continue to increase the height of the initial annular retaining wall, and finally a annular retaining wall 2 of sufficient height is formed.

[0042] After the chip 1 and the substrate 4 are soldered together through the solder balls 3, a protective film layer 5 is covered on the chip 1 and the substrate 4. The material of the protective film layer 5 is epoxy resin. In other embodiments, the protective film layer 5 can be other plastic packaging materials. Specifically, Figure 1 As shown, the protective film layer 5 includes at least a first protection zone 7 and a second protection zone 8. The first protection zone 7 covers the back and side surfaces of the chip 1 and the upper surface of the substrate outside the cavity, and the second protection zone 8 is provided on the lateral outside of the annular retaining wall 2 and within the annular groove 41. When covering the protective film layer 5, since the substrate 4 is provided with the annular groove 41 and the thickness of the annular retaining wall 2 is less than the width of the annular groove 41, the material of the protective film layer 5 will be filled into the annular groove 41. Moreover, since the bottom of the annular retaining wall 2 does not contact the upper surface of the annular groove 41, the material will also be filled between the bottom of the annular retaining wall 2 and the bottom surface of the annular groove 41. Such sufficient filling can protect the solder balls 3 in the cavity 6 and the effective area of ​​the chip 1, and can make the cavity 6 more sealed.

[0043] In one embodiment, the number of solder balls 3 is at least one and is located inside the cavity 6. The solder ball is a gold solder ball or a tin solder ball. When the solder ball is a gold solder ball, since the height of the gold solder ball is less than 50 microns, the height of the corresponding annular retaining wall 2 is also less than 50 microns; when the solder ball is a tin solder ball, since the height of the tin solder ball is generally less than 100 microns, the height of the corresponding annular retaining wall 2 is also less than 100 microns.

[0044] In a specific embodiment, to achieve a better cavity effect, the height of the annular retaining wall 2 is no less than the height of the solder ball 3 ultimately formed by welding, so that the area connecting the cavity to the outside forms a U-shaped channel. The height of the annular retaining wall 2 is no greater than the height of the initially formed solder ball 3, the depth of the annular groove 41 is greater than half the height of the initially formed solder ball 3, and the width of the annular groove 41 is no less than the thickness of the annular retaining wall 2. Because the height of the solder ball varies slightly before and after welding, the design of the annular groove 41 can prevent the bottom of the annular retaining wall from colliding with the bottom surface of the annular groove 41 during welding. At the same time, by setting the appropriate height and width, the area connecting the cavity of the annular retaining wall 2 to the outside forms a U-shaped channel. Even if the protective film layer 5 material overflows during lamination, it is difficult to enter the cavity through the U-shaped channel, thereby improving product performance.

[0045] Example 2:

[0046] A method for manufacturing a filter packaging structure comprises the following steps:

[0047] like Figure 2 As shown, an annular retaining wall 2 is provided on the front of the chip 1;

[0048] like Figure 3 As shown, solder balls 3 are soldered on the front side of the chip 1 and inside the annular retaining wall 2;

[0049] like Figure 4 As shown, a base plate 4 is provided, and the base plate 4 is provided with an annular groove 41 that cooperates with the annular retaining wall 2;

[0050] like Figure 5 As shown, the chip 1 is soldered to the substrate 4 through the solder balls 3 , and the annular retaining wall 2 is embedded in the annular groove 41 so that the chip 1 , the substrate 4 and the annular retaining wall 2 form a cavity 6 and the bottom of the annular retaining wall 2 does not contact the bottom surface of the annular groove 41 .

[0051] The method further includes the following steps: forming a protective film layer 5;

[0052] The protective film layer 5 includes at least a first protection zone and a second protection zone. The first protection zone covers the back and side surfaces of the chip 1 and the upper portion of the substrate 4 outside the cavity. The second protection zone is arranged on the side outside of the annular retaining wall 2 and in the annular groove 41. The final structure is as follows: Figure 1 shown.

[0053] The present invention solves the problem that the cavity in the traditional filter packaging structure is easily filled with glue or contaminated. In order to prevent the solder balls 3 and the effective area on the front of the chip 1 from being contaminated, an annular retaining wall 2 is provided on the front of the chip 1, and mutually matching annular grooves 41 are provided on the surface of the substrate 4. After the chip is mounted, the annular retaining wall 2 can be embedded in the annular groove 41 of the substrate 4, effectively preventing the material of the protective film layer 5 that overflows when the chip 1 and the substrate 4 are pressed together from entering the cavity 6 and contaminating the solder balls 3 and the effective area of ​​the chip 1, thereby improving the reliability of the cavity 6.

[0054] In addition, since the height of the solder ball 3 will change during the welding process, if the solder ball 3 and the annular retaining wall 2 are directly welded to the substrate 4, on the one hand, the height of the solder ball 3 will change, but the height of the annular retaining wall 2 will remain unchanged, which may lead to poor electrical contact between the chip 1 and the substrate 4 and affect the electrical performance; on the other hand, if the solder ball 3 and the annular retaining wall 2 are both welded, due to the height of the solder ball 3 and the process error of the annular retaining wall 2, there may be a gap between the annular retaining wall 2 and the substrate 4, and the cavity 6 may be contaminated. The present invention provides an annular groove 41 on the surface of the substrate 4 that cooperates with the annular retaining wall 2. During packaging, the annular retaining wall 2 does not need to be welded to the substrate 4, but only needs to be embedded in the annular groove 41 of the substrate 4. When the material of the protective film layer 5 is subsequently filled, it can be fully filled and will not flow into the cavity 6.

[0055] Furthermore, it should be noted that the specific embodiments described in this specification may vary in the shapes and names of their components. Any equivalent or simple variations based on the structure, features, and principles described in the patented concept of this invention are included within the scope of protection of this patent. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments, and these modifications, as long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, shall fall within the scope of protection of this invention.

Claims

1. A filter packaging structure, characterized in that: including a chip, a substrate and an annular retaining wall; The annular retaining wall is arranged on the front of the chip, and the surface of the substrate is provided with an annular groove that cooperates with the annular retaining wall; The chip is soldered to the substrate via solder balls, and the annular retaining wall is embedded in the annular groove so that a cavity is formed between the chip, the substrate, and the annular retaining wall, and the bottom of the annular retaining wall does not contact the bottom surface of the annular groove; Also includes a protective film layer; The protective film layer includes at least a first protection zone and a second protection zone, wherein the first protection zone covers the back and side surfaces of the chip and the substrate outside the cavity, and the second protection zone is arranged outside the annular retaining wall and inside the annular groove; There is at least one solder ball located inside the cavity; The height of the annular retaining wall is not less than the height of the solder ball finally formed by welding, so that the communication area between the cavity and the outside is a U-shaped channel; The height of the annular retaining wall is not greater than the height of the initially formed solder ball, the depth of the annular groove is greater than half the height of the initially formed solder ball, and the width of the annular groove is not less than the thickness of the annular retaining wall; The material of the annular retaining wall is PI material.

2. A method for manufacturing a filter packaging structure, characterized in that: The following steps are involved: Providing a chip, and setting an annular retaining wall on the front of the chip; welding solder balls on the front side of the chip and on the inner side of the annular retaining wall; Providing a base plate, wherein the base plate is provided with an annular groove that cooperates with the annular retaining wall; The chip is soldered to the substrate via solder balls, and the annular retaining wall is embedded in the annular groove so that a cavity is formed between the chip, the substrate, and the annular retaining wall, and the bottom of the annular retaining wall does not contact the bottom surface of the annular groove; Filling a protective film layer on the surface of the substrate and the chip; The protective film layer includes at least a first protection zone and a second protection zone, wherein the first protection zone covers the back and side surfaces of the chip and the substrate outside the cavity, and the second protection zone is arranged outside the annular retaining wall and inside the annular groove; There is at least one solder ball located inside the cavity; The height of the annular retaining wall is not less than the height of the solder ball finally formed by welding, so that the communication area between the cavity and the outside is a U-shaped channel; The height of the annular retaining wall is not greater than the height of the initially formed solder ball, the depth of the annular groove is greater than half the height of the initially formed solder ball, and the width of the annular groove is not less than the thickness of the annular retaining wall.

Images