Module packaging structure

Abstract

The utility model provides a module packaging structure, which comprises a substrate, at least one chip, an adhesive layer and at least one groove-shaped structure, and is characterized in that the chip is connected to the surface of one side of the substrate through a plurality of solder balls arranged at intervals, so that the chip and the substrate are arranged at intervals; the adhesive layer is coated on the substrate and the chip to form a sealed cavity; the groove-shaped structure is arranged on the surface of the side, facing the chip, of the substrate, and the groove-shaped structure at least penetrates through the adhesive layer in the direction perpendicular to the substrate. The module packaging structure solves the problem that the packaging structure is unstable due to the fact that the thermal expansion coefficient of the adhesive layer of the module packaging structure in the prior art is large.

Description

Technical Field

[0001] The utility model relates to the technical field of chip packaging, and particularly to a module packaging structure. Background Art

[0002] The radio frequency module is used for the separation and amplification of wireless signals in wireless devices, and one or more chips, such as switches, filters, amplifiers, etc., will be used. Each chip is welded to the substrate and then packaged into a module. For example, the surface of the filter chip is integrated with finger bars, and it is necessary to ensure that there is a cavity structure above the finger bars during use. In order to improve the integration degree and reduce the cost, the BDMP (Bare Die Module Package) packaging method is to weld the unencapsulated bare chip to the substrate, and then cover a glue layer tightly on the chip to prevent the encapsulation material from filling into the gap between the filter finger bars and the substrate during the encapsulation process, and finally perform encapsulation to complete the module chip packaging.

[0003] During the use or welding process of wireless devices, scenarios of overheating and getting hot often occur. The chip has a small coefficient of thermal expansion, and its volume changes very little with temperature. Due to the material characteristics of the glue layer used in BDMP packaging, it usually has a large coefficient of thermal expansion at high temperatures, and the expansion volume at high temperatures is much larger than that of other materials in the radio frequency module. Therefore, the warping amplitude of the radio frequency module with BDMP packaging is larger than that of the radio frequency module with other packaging methods at high temperatures, and the solder balls used for welding the chip and the substrate are subjected to greater forces at high temperatures. During the alternating process of high and low temperatures, the solder balls are more likely to break due to metal fatigue, resulting in equipment failure, thus limiting the application of this low-cost packaging method, BDMP, in radio frequency modules.

[0004] That is to say, in the prior art, there is a problem that the glue layer with a large coefficient of thermal expansion in the module packaging structure leads to the instability of the packaging structure. Summary of the Utility Model

[0005] The main purpose of the utility model is to provide a module packaging structure to solve the problem that the glue layer with a large coefficient of thermal expansion in the module packaging structure in the prior art leads to the instability of the packaging structure.

[0006] To achieve the above purpose, the utility model provides a module packaging structure, including: a substrate; at least one chip, the chip is connected to one side surface of the substrate through a plurality of spaced solder balls, so that the chip is spaced from the substrate; a glue layer, the glue layer covers the substrate and the chip to form a sealed cavity; at least one groove-shaped structure, the groove-shaped structure is arranged on one side surface of the substrate facing the chip, and the groove-shaped structure penetrates at least the glue layer in the direction perpendicular to the substrate.

[0007] Further, the width D of the groove-shaped structure on one side surface parallel to the substrate satisfies: 20 microns ≤ D ≤ 100 microns.

[0008] Further, the shortest distance L between the center of the groove structure and the chip satisfies: 60 microns ≤ L ≤ 200 microns.

[0009] Further, the module packaging structure further includes a packaging housing, and the packaging housing is disposed on the surface of the adhesive layer away from the substrate.

[0010] Further, the packaging housing has at least one protrusion extending into the groove structure, and the protrusions are arranged in one-to-one correspondence with the groove structures.

[0011] Further, the module packaging structure includes two chips, and at least one groove structure is located between the two chips.

[0012] Further, the module packaging structure includes a plurality of groove structures with different extending directions on the surface parallel to the substrate.

[0013] Further, the plurality of groove structures communicate on the surface parallel to the substrate to surround the chip for one week.

[0014] Further, the surface of the substrate facing the chip has a solder mask layer, the adhesive layer is disposed on the solder mask layer, and the groove structure penetrates through the adhesive layer and the solder mask layer.

[0015] Further, the substrate further has a plurality of alternately stacked dielectric layers and copper foil layers, the solder mask layer is disposed on the copper foil layer closest to the chip, and the solder mask layer has a plurality of hollowed-out areas exposing the copper foil layer to connect the solder balls to the copper foil layer.

[0016] Further, the surface of the chip facing the substrate has a plurality of finger bars, and a plurality of solder balls are arranged around the plurality of finger bars.

[0017] Applying the technical solution of the present utility model, the module packaging structure includes a substrate, at least one chip, an adhesive layer, and at least one groove structure. The chip is connected to one surface of the substrate through a plurality of spaced solder balls, so that the chip is spaced from the substrate; the adhesive layer coats the substrate and the chip to form a sealed cavity; the groove structure is disposed on the surface of the substrate facing the chip, and the groove structure penetrates at least the adhesive layer in the direction perpendicular to the substrate.

[0018] The module packaging structure of the present application connects the substrate and the chip with a plurality of solder balls, which play the role of electrical connection and fixation for the chip. At the same time, the solder balls lift the chip off the substrate, preventing the working surface of the chip from directly contacting the substrate. The glue layer covers the substrate and the chip, forming a sealed cavity in the gap between the substrate and the chip, preventing the external environment from polluting the working surface of the chip, and at the same time preventing the encapsulation material from filling into the gap between the working surface of the chip and the substrate during the encapsulation process, ensuring the working stability of the chip. At the same time, the module packaging structure is provided with a groove-shaped structure on the surface of the substrate facing the chip. The groove-shaped structure is formed on at least one side of the periphery of the chip, and the depth in the direction perpendicular to the substrate penetrates at least the glue layer, thereby interrupting the continuous and large-area glue layer, effectively reducing the extrusion force generated by the expansion of the glue layer on the chip and the solder balls at high temperature, and reducing the pulling force of the glue layer on the chip during cooling and contraction, avoiding the fracture of the solder balls during the alternating process of high and low temperatures, making the internal connection of the module packaging structure stable and extending the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 Shows a cross-sectional view of the module packaging structure before plastic encapsulation in Embodiment 1 of the present invention;

[0021] Figure 2 Shows Figure 1 The cross-sectional view of the module packaging structure in

[0022] Figure 3 Shows Figure 1 The top view of the module packaging structure in

[0023] Figure 4 Shows a cross-sectional view of the module packaging structure after plastic encapsulation in Embodiment 2 of the present invention.

[0024] Among them, the above-mentioned accompanying drawings include the following reference numerals:

[0025] 10. Substrate; 11. Copper foil layer; 12. Dielectric layer; 13. Solder mask layer; 20. Chip; 21. Finger bar; 22. Solder ball; 30. Glue layer; 40. Groove-shaped structure; 50. Sealed cavity; 60. Encapsulation housing; 61. Protrusion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0027] It should be noted that unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0028] In the present utility model, unless otherwise stated, orientation terms such as "upper, lower, top, bottom" generally refer to the directions shown in the drawings, or refer to the vertical, perpendicular or gravitational directions of the components themselves; similarly, for the convenience of understanding and description, "inner, outer" refer to the inner and outer of the contour of each component itself, but the above orientation terms are not used to limit the present utility model.

[0029] In order to solve the problem that the large coefficient of thermal expansion of the glue layer in the existing module packaging structure leads to unstable packaging structure, the present utility model provides a module packaging structure.

[0030] As Figures 1 to 4 shown, the module packaging structure includes a substrate 10, at least one chip 20, a glue layer 30 and at least one groove-shaped structure 40. The chip 20 is connected to one side surface of the substrate 10 through a plurality of spaced solder balls 22, so that the chip 20 is spaced from the substrate 10; the glue layer 30 covers the substrate 10 and the chip 20 to form a sealed cavity 50; the groove-shaped structure 40 is arranged on one side surface of the substrate 10 facing the chip 20, and the groove-shaped structure 40 penetrates at least the glue layer 30 in the direction perpendicular to the substrate 10.

[0031] The module packaging structure of the present application uses a plurality of solder balls 22 to connect the substrate 10 and the chip 20, which plays an electrical connection and fixing role for the chip 20. At the same time, the solder balls 22 lift the chip 20 off the ground, avoiding direct contact between the working surface of the chip 20 and the substrate 10. The glue layer 30 covers the substrate 10 and the chip 20, so that the gap between the substrate 10 and the chip 20 forms a sealed cavity 50, avoiding environmental pollution of the working surface of the chip 20 by the outside world, and at the same time preventing the packaging material from filling into the gap between the working surface of the chip 20 and the substrate 10 during the packaging process, ensuring the working stability of the chip 20. At the same time, the module packaging structure is provided with a groove-shaped structure 40 on one side surface of the substrate 10 facing the chip 20. The groove-shaped structure 40 is formed on at least one side of the periphery of the chip 20, and the depth in the direction perpendicular to the substrate 10 at least penetrates the glue layer 30, thereby interrupting the continuous and large-area glue layer 30, effectively reducing the extrusion force generated by the expansion of the glue layer 30 on the chip 20 and the solder balls 22 at high temperature, and reducing the pulling force of the glue layer 30 on the chip 20 during cooling and contraction, avoiding the fracture of the solder balls 22 during the alternating process of high and low temperatures, making the internal connection of the module packaging structure stable and extending the service life.

[0032] As Figures 1 to 4As shown, one side surface of the chip 20 facing the substrate 10 has a plurality of finger bars 21, and a plurality of solder balls 22 surround the outside of the plurality of finger bars 21. That is to say, one side surface of the chip 20 facing the substrate 10 is the working surface, and the working surface has a plurality of finger bars 21. Among them, the soldering area of the solder balls 22 is outside the setting area of all the finger bars 21, that is, it gives way to the finger bars 21 to avoid affecting the normal function of the chip 20, and at the same time, all the finger bars 21 can be protected inside, reducing the risk of the finger bars 21 being contaminated.

[0033] It should be noted that the chip 20 and the substrate 10 are spaced apart, so that the soldering connection method of the chip 20 is flip-chip soldering. The working surface of the chip 20 with finger bars 21 faces the substrate 10 and does not contact the substrate 10, providing a gap for the working surface of the chip 20 and avoiding damage to the working surface of the chip 20.

[0034] As Figures 1 to 4 shown, the width D of the groove-shaped structure 40 on one side surface parallel to the substrate 10 satisfies: 20 μm ≤ D ≤ 100 μm. The width D of the groove-shaped structure 40 on one side surface parallel to the substrate 10 can be flexibly set according to the size of the chip 20, the thermal expansion coefficient of the adhesive layer 30, and the pressure-bearing capacity of the adhesive layer 30. By restricting D within a certain range, the lateral force of the adhesive layer 30 during expansion and contraction on the soldering connection between the chip 20 and the substrate 10 is fully dissipated.

[0035] Optionally, the shape of the groove-shaped structure 40 is a rectangular groove, that is, the width D of the groove-shaped structure 40 is the same up and down, which is convenient for processing the groove-shaped structure 40.

[0036] As Figures 1 to 4 shown, the shortest distance L between the center of the groove-shaped structure 40 and the chip 20 satisfies: 60 μm ≤ L ≤ 200 μm. That is to say, the center of the groove-shaped structure 40 and the chip 20 have the shortest distance L. If L is too small, the distance between the groove-shaped structure 40 and the chip 20 is very close, not only the fixing effect on the chip 20 is poor, but even the sealed cavity 50 may be damaged, contaminating the working surface of the chip 20; if L is too large, that is, the groove-shaped structure 40 is far from the chip 20, the chip 20 will still be squeezed or pulled by a large area of the adhesive layer 30, and the stability of the module packaging structure is poor. By restricting L within a certain range, it is ensured that the lateral force of the adhesive layer 30 on the chip 20 in the high-low temperature alternating environment is small.

[0037] As Figures 1 to 4As shown, the module packaging structure further includes a packaging housing 60, and the packaging housing 60 is disposed on the surface of the adhesive layer 30 away from the substrate 10. That is to say, the packaging housing 60 can be formed on the adhesive layer 30, and the setting of the sealed cavity 50 avoids the working surface of the chip 20 being contaminated by the packaging material during the forming process of the packaging housing 60. In addition, the packaging housing 60 has high hardness after curing, which can provide good support for the module packaging structure.

[0038] As Figures 1 to 4 shown, the packaging housing 60 has at least one protrusion 61 extending into the groove-shaped structure 40, and the protrusions 61 are arranged in one-to-one correspondence with the groove-shaped structures 40. That is to say, during the packaging process, the material of the packaging housing 60 fills the groove-shaped structure 40, and after the packaging housing 60 is cured, a protrusion 61 extending into the groove-shaped structure 40 is formed, which improves the connection stability between the packaging housing 60 and the substrate 10, and at the same time further hinders the transmission of the lateral force in the adhesive layer 30.

[0039] As Figures 1 to 4 shown, the module packaging structure includes a plurality of groove-shaped structures 40 with different extension directions on the surface parallel to the substrate 10. That is to say, the groove-shaped structures 40 can have different extension directions on the surface parallel to the substrate 10, that is, the extrusion or pulling of the adhesive layer 30 on the chip 20 is blocked in multiple directions, further reducing the influence of the adhesive layer 30 on the chip 20 and improving the structural stability.

[0040] As Figures 1 to 4 shown, the surface of the substrate 10 facing the chip 20 has a solder mask layer 13, the adhesive layer 30 is disposed on the solder mask layer 13, and the groove-shaped structure 40 penetrates through the adhesive layer 30 and the solder mask layer 13. That is to say, the solder mask layer 13 and the adhesive layer 30 are sequentially laid on the substrate 10, and the setting of the solder mask layer 13 effectively avoids the risk of electrical short circuit and improves the electrical performance of the product. At the same time, the groove-shaped structure 40 can penetrate through the adhesive layer 30 and the solder mask layer 13, and deepening the groove-shaped structure 40 can make the protrusion 61 of the packaging housing 60 have a greater thickness and be more stably connected to the substrate 10.

[0041] As Figures 1 to 4 shown, the substrate 10 further has a plurality of alternately stacked dielectric layers 12 and copper foil layers 11, the solder mask layer 13 is disposed on the copper foil layer 11 closest to the chip 20, and the solder mask layer 13 has a plurality of hollow areas exposing the copper foil layer 11 to connect the solder balls 22 to the copper foil layer 11. That is to say, the substrate 10 further includes a plurality of alternately stacked dielectric layers 12 and copper foil layers 11, and the solder mask layer 13 is attached to the copper foil layer 11 of the substrate 10 closest to the adhesive layer 30, providing a structural condition for soldering the substrate 10 and the chip 20. At the same time, the solder mask layer 13 has a plurality of hollow areas exposing the copper foil layer 11 to achieve the purpose of connecting the solder balls 22 to the copper foil layer 11 and meet the conduction condition between the substrate 10 and the chip 20.

[0042] Embodiment 1

[0043] As Figures 1 to 3 shown, the module packaging structure includes a substrate 10, two chips 20, an adhesive layer 30, and a plurality of groove-shaped structures 40 with different extension directions. The chips 20 are connected to one side surface of the substrate 10 through a plurality of solder balls 22 arranged at intervals, so that the chips 20 are spaced apart from the substrate 10; the adhesive layer 30 is coated on the substrate 10 and the chips 20 to form a sealed cavity 50; the groove-shaped structures 40 are arranged on one side surface of the substrate 10 facing the chips 20, and the groove-shaped structures 40 penetrate at least the adhesive layer 30 in a direction perpendicular to the substrate 10.

[0044] As Figure 2 shown, a plurality of groove-shaped structures 40 communicate with each other. One of the groove-shaped structures 40 is arranged between the two chips 20, and the high and low temperature stresses of the two chips 20 can be relieved. The remaining groove-shaped structures 40 surround the two chips 20 in a circumferential direction. The groove-shaped structures 40 penetrate the adhesive layer 30 and the solder mask layer 13 in a direction perpendicular to the substrate 10. Finally, the protrusion 61 of the packaging shell 60 extends into all the groove-shaped structures 40.

[0045] Preferably, the opening direction of the groove-shaped structure 40 is parallel to the edge of the chip 20, which is beneficial to evenly dissipate the extrusion or traction of the adhesive layer 30 around the chip 20, and improve the stability of the module packaging structure.

[0046] Embodiment 2

[0047] As Figure 4 shown, the difference from Embodiment 1 is that the number and positions of the groove-shaped structures 40 are different.

[0048] As Figure 4 shown, there is no groove-shaped structure 40 between the two chips 20, which can reduce the processing difficulty and further reduce the packaging cost.

[0049] It should be noted that if the high and low temperature forces on two or more chips 20 themselves are relatively small or concentrated in one area for placement, the groove-shaped structures 40 may not be provided between the chips 20.

[0050] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0051] 1. A plurality of solder balls 22 connect the substrate 10 and the chips 20, playing an electrical connection and fixing role for the chips 20. At the same time, the solder balls 22 suspend the chips 20, avoiding direct contact between the working surfaces of the chips 20 and the substrate 10.

[0052] 2. The adhesive layer 30 wraps the substrate 10 and the chip 20, so that the gap between the substrate 10 and the chip 20 forms a sealed cavity 50, avoiding environmental pollution of the working surface of the chip 20 by the outside world, and at the same time preventing the encapsulation material from filling into the gap between the working surface of the chip 20 and the substrate 10 during the encapsulation process, ensuring the working stability of the chip 20.

[0053] 3. The module packaging structure is provided with a groove-shaped structure 40 on the surface of the substrate 10 facing the chip 20. The groove-shaped structure 40 is formed on at least one side around the chip 20, and its depth in the direction perpendicular to the substrate 10 penetrates at least through the adhesive layer 30, thereby interrupting the continuous and large-area adhesive layer 30, effectively reducing the extrusion force generated by the expansion of the adhesive layer 30 on the chip 20 and the solder balls 22 at high temperature, and reducing the pulling of the adhesive layer 30 on the chip 20 during cooling and contraction, avoiding the fracture of the solder balls 22 during the alternation of high and low temperatures, making the internal connection of the module packaging structure stable and extending the service life.

[0054] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] It should be noted that the terms used herein are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0056] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0057] The above are only the preferred embodiments of the present invention, and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A module packaging structure, characterized in that, Comprising: A substrate (10); At least one chip (20), the chip (20) being connected to one side surface of the substrate (10) by a plurality of spaced solder balls (22) such that the chip (20) is spaced from the substrate (10); An adhesive layer (30), the adhesive layer (30) covering the substrate (10) and the chip (20) to form a sealed cavity (50); At least one groove structure (40), the groove structure (40) being provided on one side surface of the substrate (10) facing the chip (20), the groove structure (40) penetrating at least the adhesive layer (30) in a direction perpendicular to the substrate (10).

2. The module packaging structure according to claim 1, wherein The width D of the groove structure (40) on a side surface parallel to the substrate (10) satisfies: 20 μm ≤ D ≤ 100 μm.

3. The module packaging structure according to claim 1, wherein The shortest distance L between the center of the groove structure (40) and the chip (20) satisfies: 60 μm ≤ L ≤ 200 μm.

4. The module packaging structure according to claim 1, characterized in that The module packaging structure further includes a packaging shell (60), the packaging shell (60) being provided on one side surface of the adhesive layer (30) away from the substrate (10).

5. The module packaging structure according to claim 4, wherein The packaging shell (60) has at least one protrusion (61) extending into the groove structure (40), the protrusion (61) being provided in one-to-one correspondence with the groove structure (40).

6. The module packaging structure according to claim 1, wherein, The module packaging structure includes two of the chips (20), and at least one of the groove structures (40) is located between the two chips (20).

7. The module packaging structure according to claim 1, wherein The module packaging structure includes a plurality of groove structures (40) having different extending directions on a surface parallel to the substrate (10).

8. The module packaging structure according to claim 7, wherein, The plurality of groove structures (40) communicate with each other on a surface parallel to the substrate (10) to surround the chip (20) in a circle.

9. The module packaging structure according to any one of claims 1 to 8, characterized in that, One side surface of the substrate (10) facing the chip (20) has a solder mask layer (13), the adhesive layer (30) is provided on the solder mask layer (13), and the groove structure (40) penetrates the adhesive layer (30) and the solder mask layer (13).

10. The module packaging structure according to claim 9, wherein, The substrate (10) further has a plurality of alternately stacked dielectric layers (12) and copper foil layers (11), the solder mask layer (13) is provided on the copper foil layer (11) closest to the chip (20), and the solder mask layer (13) has a plurality of hollowed-out areas exposing the copper foil layer (11) to connect the solder balls (22) to the copper foil layer (11).

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