Package structure

Abstract

The utility model provides a packaging structure. The packaging structure comprises a substrate; an electronic component disposed on the substrate; the electric connecting piece is electrically connected with the electronic element and the substrate; an interposer disposed between the substrate and the electronic component and covering the electrical connector; a mold sealing layer covering the electronic component and the interposer, the mold sealing layer having flexibility; the flexibility of the substrate is less than that of the interposer, and the flexibility of the interposer is less than that of the molding layer. The packaging structure provided by the embodiment of the utility model at least can reduce the risk that the joint of the substrate and the electric connector is broken.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and more specifically, to a packaging structure. Background Art

[0002] Due to the needs of the times, flexible electronic devices are increasing day by day. With the continuous development of flexible electronic devices, rigid-flex boards are made by combining flexible circuit boards and rigid circuit boards, which have both flexibility and circuit board strength. However, in the current application of rigid-flex boards, it is often found that the rigid-flex boards are cracked after the rolling test. Figure 1 is a cross-sectional schematic diagram of a packaging structure 50 in the prior art, Figure 2 yes Figure 1 The enlarged view of the local area C of the Figure 2 Unnecessary structures are omitted in Figure 1 and Figure 2 For illustration, the package structure 50 includes a hard electronic component 51 and a soft substrate 53, and the electronic component 51 and the substrate 53 are electrically connected through a bump 55 (such as a solder ball). There are two points where cracks often occur. The first crack 61 is where the edge of the electronic component 51 extends downward to the substrate 53, and the second crack 62 is the connection between the electronic component 51 and the substrate 53 through the bump 55. The occurrence of cracks will cause the circuit of the substrate 53 to be destroyed and the electrical connection between the electronic component 51 and the substrate 53 to deteriorate. The reason for the cracks is that the first crack 61 is the place where the edge of the electronic component 51 exerts shear stress concentration on the substrate 53 when the package structure 50 is bent. In addition, the bump 55 will also cause stress concentration, and the heterogeneous combination is also prone to breakage after multiple product bending. This is the most urgent problem to be solved at present. Figure 3 Shows the bending state Figure 1 The packaging structure 50, the winding test is to roll the packaging structure 50 into a bent state and then unfold it, and then repeat the rolling and unfolding actions. Utility Model Content

[0003] In view of the above problems existing in the prior art, an embodiment of the present application proposes a packaging structure, which can at least reduce the risk of cracking at the connection between the substrate and the electrical connector.

[0004] According to one aspect of the present application, a packaging structure is provided, which includes: a substrate; an electronic component, which is arranged on the substrate; an electrical connector, which electrically connects the electronic component and the substrate; an intermediate layer, which is arranged between the substrate and the electronic component and covers the electrical connector; a molding layer, which covers the electronic component and the intermediate layer, and the molding layer is flexible; the flexibility of the substrate is less than the flexibility of the intermediate layer, and the flexibility of the intermediate layer is less than the flexibility of the molding layer.

[0005] In one or more embodiments, in a cross section perpendicular to a rolling axis when the interposer is wound, a horizontal length of the interposer is greater than a horizontal length of the electronic component.

[0006] In one or more embodiments, an intersection between an upper surface or a lower surface of the interposer and a side surface of the interposer is rounded.

[0007] In one or more embodiments, in the vertical direction, the electrical connection member is a linear electrical connection line.

[0008] In one or more embodiments, the intervals between two adjacent electrical connectors at different heights are inconsistent.

[0009] In one or more embodiments, the electrical connector is a wire bond.

[0010] In one or more embodiments, the extension lengths of the plurality of electrical connectors from the substrate to the electronic component are different from each other.

[0011] In one or more embodiments, the packaging structure further includes a solder ball located between the electrical connector and the electronic component, and the electrical connector is electrically connected to the electronic component through the solder ball.

[0012] In one or more embodiments, the electrical connector has an end surface connected to the solder ball, and the end surface is flush with the upper surface of the interposer.

[0013] In one or more embodiments, a bottom surface of the molding layer is in direct contact with an upper surface of the substrate.

[0014] In one or more embodiments, a side surface of the molding layer is flush with a side surface of the substrate.

[0015] In one or more embodiments, the packaging structure is a bendable flexible structure.

[0016] In one or more embodiments, a lower surface of the interposer is in direct contact with the substrate.

[0017] In one or more embodiments, a vertical projection of the interposer on the substrate falls within the boundaries of the substrate.

[0018] In one or more embodiments, the flexibility of the electronic component is less than the flexibility of the substrate.

[0019] In one or more embodiments, the bonding wire is a silver wire.

[0020] In one or more embodiments, the melting point of the solder ball is lower than the melting point of the electrical connector.

[0021] In one or more embodiments, a maximum thickness of the molding layer is greater than a thickness of the substrate.

[0022] According to another aspect of the present application, another packaging structure is provided, which includes: an electronic component arranged on a substrate; an electrical connector arranged between the electronic component and the substrate; an intermediate layer covering the electrical connector; and a molding layer arranged on the substrate and covering the intermediate layer and the electronic component; wherein the stiffness of the electronic component, the stiffness of the substrate, the stiffness of the intermediate layer, and the stiffness of the molding layer decrease in sequence.

[0023] In one or more embodiments, the molding layer has a first portion located above the electronic component and a second portion surrounding a peripheral side of the electronic component, and an upper surface of the first portion is flush with an upper surface of the second portion.

[0024] The beneficial technical effects of the utility model are:

[0025] The packaging structure of the embodiment of the present application has an intermediate layer with flexibility / rigidity between the substrate and the molding layer. The intermediate layer covers the electrical connector and can at least provide buffering, disperse the stress concentrated on the substrate, and reduce the risk of cracking at the connection between the substrate and the electrical connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work. It is worth noting that according to the standard practice of the industry, the various components are not drawn to scale and are only used for illustration purposes. In fact, for the clarity of discussion, the size of each component can be arbitrarily increased or reduced.

[0027] Figure 1 It is a cross-sectional schematic diagram of a packaging structure in the prior art.

[0028] Figure 2 yes Figure 1 A magnified view of a local area C

[0029] Figure 3 Shows the bending state Figure 1 packaging structure.

[0030] Figure 4Ais a schematic cross-sectional view of a packaging structure according to an embodiment of the present application.

[0031] Figure 4B SEM images of solder balls and interposer-wrapped electrical connectors are shown.

[0032] Figure 5-Figure 10 It is a cross-sectional schematic diagram at multiple steps of a process flow for forming a packaging structure according to an embodiment of the present application.

[0033] Fig.11 It is an enlarged schematic diagram of a local area of ​​the package structure, showing the status of the solder balls and electrical connectors before passing through the furnace.

[0034] Fig.12 It is an enlarged schematic diagram of a local area of ​​the package structure, showing the status of the solder balls and electrical connectors after passing through the furnace. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0036] The following disclosure provides many different embodiments or examples for realizing different features of the provided subject matter. Specific examples of components and arrangements will be described below to simplify the present invention. Of course, these are merely examples and are not intended to limit the present invention. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are in direct contact, and may also include an embodiment in which an additional component is formed between the first component and the second component so that the first component and the second component may not be in direct contact. Moreover, the present invention may repeatedly refer to numbers and / or letters in various examples. This repetition is only for simplicity and clarity, and does not itself represent the relationship between the various embodiments and / or configurations discussed.

[0037] In addition, the embodiments in the present application and the features in the embodiments may be combined with each other in the absence of conflicts. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. It should be understood that the specific structures shown in the drawings are only for the sake of convenience of explanation and are not intended to limit the present application. When describing a specific figure, other structures not described in the drawings may be provided according to actual needs and are not intended to limit the present application.

[0038] Figure 4A FIG. 1 is a schematic cross-sectional view of a package structure 10 according to an embodiment of the present application. Figure 4AAs shown, the packaging structure 10 of the present application includes a substrate 11, an electronic component 15, an electrical connector 13, an interposer 17, and a mold sealing layer 19, wherein the electronic component 15 is disposed on the substrate 11, the electrical connector 13 and the interposer 17 are disposed between the substrate 11 and the electronic component 15, the electrical connector 13 electrically connects the electronic component 15 and the substrate 11, the interposer 17 covers the electrical connector 13, the mold sealing layer 19 covers the electronic component 15 and the interposer 17, and the mold sealing layer 19 is flexible, the flexibility of the substrate 11 is less than the flexibility of the interposer 17, and the flexibility of the interposer 17 is less than the flexibility of the mold sealing layer 19. The packaging structure 10 of the present application has an interposer 17 whose flexibility is between the substrate 11 and the mold sealing layer 19, and the interposer 17 covers the electrical connector 13, which can at least provide a buffer, disperse the stress concentrated on the substrate 11, and reduce the risk of rupture at the connection between the substrate 11 and the electrical connector 13.

[0039] In some embodiments, the flexibility of the electronic component 15 is less than the flexibility of the substrate 11 .

[0040] From the perspective of rigidity, the rigidity of the electronic component 15 is greater than that of the substrate 11 (it can be said that the electronic component 15 is relatively "hard" and the substrate 11 is relatively "soft"); the rigidity of the substrate 11 is greater than that of the intermediate layer 17 (it can be said that the substrate 11 is relatively "hard" and the intermediate layer 17 is relatively "soft"); the rigidity of the intermediate layer 17 is greater than that of the encapsulation layer 19 (it can be said that the intermediate layer 17 is relatively "hard" and the encapsulation layer 19 is relatively "soft"); the existence of the intermediate layer 17 means that the electronic component 15 and the substrate 11 are not directly connected, but are buffered by the intermediate layer 17; the rigidity of the intermediate layer 17 is between the "softest" encapsulation layer 19 and the relatively "hard" substrate 11, which makes the semiconductor structure 10 have a certain flexibility without making the bending radius too exaggerated, thus achieving a balance between "soft" and "hard".

[0041] In some embodiments, in a cross section perpendicular to the rolling axis when the intermediate layer 17 is wound, the horizontal length of the intermediate layer 17 is greater than the horizontal length of the electronic component 15. Figure 4A In the cross section shown, in the X direction, the horizontal length of the interposer 17 is greater than the horizontal length of the electronic component 15. The horizontal length of the interposer 17 is greater than the horizontal length of the electronic component 15, which can further prevent the substrate 11 from receiving stress.

[0042] In some embodiments, the intersection of the upper surface 171 or the lower surface 173 of the intermediary layer 17 and the side surface 172 of the intermediary layer 17 is rounded. In other words, the corners of the intermediary layer 17 are rounded.

[0043] In some embodiments, in the vertical direction, the electrical connector 13 is a linear electrical connector, which can be linear or non-linear. In some embodiments, the spacing between two adjacent electrical connectors 13 at different heights is inconsistent. In some embodiments, the extension lengths of multiple electrical connectors 13 from the substrate 11 to the electronic component 15 are different. In some embodiments, the electrical connector 13 is a bonding wire, which can be a silver wire. The packaging structure 10 of the embodiment of the present application uses bonding wires and an intermediate layer 17 that covers the bonding wires to replace the original bump connection, which can avoid breakage caused by direct soft and hard connections. In addition, since the bonding wires are more flexible and are covered by the intermediate layer 17, the stability of the electrical connection can be increased.

[0044] In some embodiments, the package structure 10 may further include a solder ball 21 located between the electrical connector 13 and the electronic component 15, and the electrical connector 13 is electrically connected to the electronic component 15 through the solder ball 21. In some embodiments, the melting point of the solder ball 21 is lower than the melting point of the electrical connector 13. The electronic component 15 can utilize the wetting property of the solder ball 21. The package structure 10 of the embodiment of the present application also includes the solder ball 21 to increase the stability of the electrical connection. In some embodiments, the electrical connector 13 has an end face 131 connected to the solder ball 21, and the end face 131 is flush with the upper surface 171 of the interposer 17.

[0045] Figure 4B FIG. 1 shows a scanning electron microscope image of the solder ball 21 and the electrical connector 13 covered by the interposer 17 . Figure 4B As shown, the electrical connector 13 is a non-linear electrical connector line, and the distances between two adjacent electrical connectors 13 at different heights are inconsistent.

[0046] Continue to refer Figure 4A As shown, in some embodiments, the encapsulation layer 19 is disposed on the substrate 11 to cover the electronic component 15 and the interposer 17, and the bottom surface 191 of the encapsulation layer 19 is in direct contact with the upper surface 111 of the substrate 11. In some embodiments, the side surface 192 of the encapsulation layer 19 is flush with the side surface 112 of the substrate 11. In some other embodiments, the encapsulation layer 19 may further extend downward to cover the side surface 112 of the substrate 11, that is, the side surface 192 of the encapsulation layer 19 may be outside the side surface 112 of the substrate 11.

[0047] In some embodiments, the lower surface 173 of the interposer 17 is in direct contact with the substrate 11. In some embodiments, the vertical projection of the interposer 17 on the substrate 11 falls within the boundary of the substrate 11.

[0048] In some embodiments, the maximum thickness of the encapsulation layer 19 is greater than the thickness of the substrate 11 .

[0049] In some embodiments, package structure 10 is a bendable flexible structure.

[0050] Continue to refer Figure 4A According to another embodiment of the present application, a package structure 10 may include: an electronic component 15 disposed on a substrate 11; an electrical connector 13 disposed between the electronic component 15 and the substrate 11; an interposer 17 covering the electrical connector 13; and a mold encapsulation layer 19 disposed on the substrate 11 and covering the interposer 17 and the electronic component 15, wherein the stiffness of the electronic component 15, the stiffness of the substrate 11, the stiffness of the interposer 17, and the stiffness of the mold encapsulation layer 19 decrease in sequence. The package structure 10 of the present application has an interposer 17 covering the electrical connector 13 disposed between the electronic component 15 and the substrate 11, wherein the stiffness of the electronic component 15, the stiffness of the substrate 11, the stiffness of the interposer 17, and the stiffness of the mold encapsulation layer 19 decrease in sequence, and the interposer 17 can at least provide a buffer, disperse the stress concentrated on the substrate 11, and reduce the risk of cracking at the connection between the substrate 11 and the electrical connector 13.

[0051] In some embodiments, the molding layer 19 has a first portion 193 located above the electronic component 15 and a second portion 194 surrounding the peripheral side of the electronic component 15 , and an upper surface 1931 of the first portion 193 is flush with an upper surface 1941 of the second portion 194 .

[0052] Figure 5-Figure 10 1 is a schematic cross-sectional view of multiple steps of a process flow for forming a package structure 10 according to an embodiment of the present application.

[0053] refer to Figure 5 As shown, a substrate 11 is provided, and a plurality of pads 116 are provided on one side of the substrate 11 .

[0054] refer to Figure 6 As shown, a bonding wire is formed on each of the plurality of pads 116 to form an electrical connection 13 , and the electrical connection 13 may be a silver wire.

[0055] refer to Figure 7 As shown, an intermediate layer 17 covering the electrical connector 13 is formed. The material of the intermediate layer 17 is optional. The material of the intermediate layer 17 can be silicone rubber, polycarbonate (PC) or polyimide (PI) and the like.

[0056] refer to Figure 8 As shown, a grinding process is performed so that the end surface 131 of the electrical connector 13 is flush with the upper surface 171 of the interposer 17 .

[0057] refer to Fig. 9As shown, a solder ball 21 is placed on the end surface 131 of the electrical connector 13, and then the electronic component 15 is mounted on the solder ball 21 by surface mounting technology (SMT), so that the electrical connector 13 is electrically connected to the electronic component 15 through the solder ball 21. In other words, the substrate 11 and the electronic component 15 are electrically connected together through the solder pad 116, the electrical connector 13, and the solder ball 21. In the cross-sectional view shown in the figure, the interposer 17 covers the electrical connector 13 between the electronic component 15 and the substrate 11, and the horizontal length of the interposer 17 is greater than the horizontal length of the electronic component 15.

[0058] refer to Fig.10 As shown, the electronic component 15 and the intermediate layer 17 are molded by the mold layer 19, and the bottom surface 191 of the mold layer 19 is in direct contact with the upper surface 111 of the substrate 11, wherein the flexibility of the electronic component 15 is less than the flexibility of the substrate 11, the flexibility of the substrate 11 is less than the flexibility of the intermediate layer 17, and the flexibility of the intermediate layer 17 is less than the flexibility of the mold layer 19. Fig.10 As can be seen from the figure, the electronic component 15, the intermediate layer 17 and the electrical connector 13 are embedded in the whole formed by the molding layer 19 and the substrate 11 to form an integrated structure. Fig. 9 The solder ball 21 shown in FIG. Fig.10 The solder ball 21 shown in FIG. 1 is different in shape because Fig. 9 The solder ball 21 shown in FIG. 1 has not yet been through the furnace. Fig.10 The solder ball 21 shown in FIG. 1 is a state after being passed through a furnace.

[0059] Fig.11 FIG. 1 is an enlarged schematic diagram of a local area of ​​the package structure 10, showing the state of the solder ball 21 and the electrical connector 13 before passing through the furnace. Fig.12 It is an enlarged schematic diagram of a local area of ​​the package structure 10 , showing the state of the solder ball 21 and the electrical connector 13 after being passed through the furnace. Fig.11 and Fig.12 The shape of the electrical connector 13 is Fig.10 The shapes of the electrical connectors 13 are different. It should be understood that those skilled in the art can set electrical connectors 13 of different shapes according to needs.

[0060] refer to Fig.11 As shown, before the furnace, there is a certain degree of offset between the solder ball 21 and the electrical connector 13. By utilizing the wetting characteristics of the solder ball 21, refer to Fig.12 As shown, after passing through the furnace, the solder ball 21 and the electrical connector 13 can reach an aligned state. In other words, the solder ball 21 can correct the offset of the electrical connector 13 (such as copper wire, silver wire) after passing through the furnace, and can compensate for a certain degree of offset, thereby increasing the stability of the electrical connection.

[0061] The present application relates to flexible devices, wherein the electronic components may involve system-level packaging (SiP) technology, the substrate may be a polyimide flexible circuit board (PI FPC), and the overall packaging structure is a bendable flexible structure. The substrate, interposer, electrical connector, electronic component and mold sealing layer in the packaging structure of the present application constitute a whole, wherein the "hardest" electronic component is buried in the mold sealing layer, and the electronic component is electrically connected to the substrate connected to the mold sealing layer through the electrical connector, which can achieve the purpose of an integrated structure and has a certain bending resistance. The packaging structure of the present application adds an interposer between the electronic component and the substrate, which can, on the one hand, concentrate stress on the interposer, and on the other hand, the interposer can stabilize and protect the electrical connector to prevent the electrical connector from being directly bent and broken by external force. The packaging structure of the present application can increase the electrical reliability of the device in a bent state.

[0062] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A packaging structure, characterized in that: include: substrate; An electronic component is disposed on the substrate; An electrical connector electrically connecting the electronic component and the substrate; An intermediary layer is disposed between the substrate and the electronic component and covers the electrical connector; A mold sealing layer, covering the electronic component and the intermediate layer, and the mold sealing layer is flexible; The flexibility of the substrate is smaller than that of the intermediate layer, and the flexibility of the intermediate layer is smaller than that of the molding layer.

2. The packaging structure according to claim 1, characterized in that: In a cross section perpendicular to a rolling axis when the interposer is wound, a horizontal length of the interposer is greater than a horizontal length of the electronic component.

3. The packaging structure according to claim 2, characterized in that: The intersection of the upper surface or the lower surface of the intermediate layer and the side surface of the intermediate layer is a rounded corner.

4. The packaging structure according to claim 1, characterized in that: In the vertical direction, the electrical connection member is a linear electrical connection line.

5. The packaging structure according to claim 4, characterized in that: The distances between two adjacent electrical connectors at different heights are inconsistent.

6. The packaging structure according to claim 5, characterized in that: The electrical connector is a wire bonding device.

7. The packaging structure according to claim 5, characterized in that: The extension lengths of the plurality of electrical connectors from the substrate to the electronic component are different from each other.

8. The packaging structure according to claim 1, characterized in that: It also includes a solder ball located between the electrical connector and the electronic component, and the electrical connector is electrically connected to the electronic component through the solder ball.

9. The packaging structure according to claim 8, characterized in that: The electrical connector has an end surface connected to the solder ball, and the end surface is flush with the upper surface of the intermediary layer.

10. The packaging structure according to claim 1, characterized in that: The maximum thickness of the molding layer is greater than the thickness of the substrate.

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