Packaging structure and packaging method

Abstract

A package structure is disclosed. The package structure includes a base, a first die, a first adhesive layer, a second die, and a second adhesive layer. The first die is disposed on the base, and the first adhesive layer is disposed between the first die and the base so that the first die is fixed on the base. The second die performs at least one specific function when powered on. The second die is disposed on the first die, and the second adhesive layer is disposed between the second die and the first die so that the second die is fixed on the first die. The second die is insulated from the base at least through the first die.

Description

Technical Field

[0001] This application relates to a packaging structure, and more particularly to a packaging structure that can insulate the die from the packaging substrate. Background Technology

[0002] Chip packaging protects semiconductor chips from physical damage and environmental influences, and facilitates the integration of chips with different functions into electronic devices. Generally, the packaging process includes the following steps: mounting the die on a substrate, performing wire bonding, and then using molding compound to encapsulate the die and bonding wires onto the substrate of the package structure.

[0003] In some applications, the die must be insulated from the substrate. To achieve this, in some prior art, an insulating layer is formed on the back side of the die using semiconductor processes. However, since semiconductor processes and wafer packaging processes are different, using semiconductor processes to form the insulating layer increases the cost and complexity of the packaging process. Furthermore, although the adhesive layer between the die and the substrate can be used as an insulating layer, the thickness and insulation level of the adhesive layer are difficult to control, often resulting in poor insulation between the die and the substrate, causing the circuitry within the die to malfunction. In this situation, it is necessary to propose a suitable packaging structure or method to ensure insulation between the die and the substrate. Summary of the Invention

[0004] One embodiment of this application provides a packaging structure. The packaging structure includes a substrate, a first die, a first adhesive layer, a second die, and a second adhesive layer. The first die is disposed on the substrate. The first adhesive layer is disposed between the first die and the substrate to fix the first die to the substrate. The second die is used to perform at least one specific function when energized, and the second die is disposed on the first die. The second adhesive layer is disposed between the second die and the first die to fix the second die to the first die. The second die is insulated from the substrate at least through the first die.

[0005] Another embodiment of this application provides a packaging method. The packaging method includes: obtaining a substrate, obtaining a first die, fixing the first die to the substrate through a first adhesive layer, obtaining a second die, and fixing the second die to the first die through a second adhesive layer. The second die is used to perform at least one specific function when energized, and the second die is insulated from the substrate at least through the first die. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the packaging structure of a comparative embodiment of this application;

[0007] Figure 2 This is a schematic diagram of the packaging structure according to an embodiment of this application;

[0008] Figure 3 This is a schematic diagram of the packaging structure according to another embodiment of this application;

[0009] Figure 4 This is a flowchart of an embodiment of the encapsulation method of this application;

[0010] Figures 5A to 5H This is an embodiment of the present application. Figure 4 A cross-sectional view of one or more stages in the packaging method for manufacturing the packaging structure;

[0011] Figure 6 This is a schematic cross-sectional view of a wafer being cut to obtain a die according to an embodiment of this application;

[0012] Figure 7 This is a schematic cross-sectional view of an embodiment of the present application showing how grains are fixed to a substrate by an adhesive layer. Detailed Implementation

[0013] Figure 1 This is a schematic diagram of a package structure 100 according to a comparative embodiment of this application. The package structure 100 includes a base 110, a die 120, an adhesive layer 130, lead pads 140, bonding wires 150, and a molding layer MD1. Figure 1 In this configuration, the die 120 can be fixed to the substrate 110 via the adhesive layer 130. The die 120 may have at least one solder pad 122, and the solder pad 122 can be coupled to the lead pad 140 via a bonding wire 150. The molding layer MD1, for example, but not limited to, epoxy resin, can mold the die 120, the adhesive layer 130, and the bonding wire 150 onto the substrate 110 and the lead pad 140. Figure 1 In this application, the die 120 must be insulated from the substrate 110. Therefore, the adhesive layer 130 can be, for example, a die-attach film (DAF) or an epoxy layer with insulating properties. However, since the thickness of the die-attach film is relatively thin and the thickness of the epoxy layer is difficult to control, the insulating effect of the adhesive layer 130 is relatively limited. In this case, the insulation effect between the die 120 and the substrate 110 is relatively unstable, which may cause the circuit in the die 120 to malfunction, resulting in a low yield of the package structure 100.

[0014] To address this issue, embodiments of this application propose a packaging structure that utilizes redundant dies to provide better insulation between the functional die and the substrate. Figure 2 This is a schematic diagram of a packaging structure 200 according to an embodiment of this application. The packaging structure 200 includes a base 210, a first die 220, a first adhesive layer 230, a second die 240, and a second adhesive layer 250.

[0015] like Figure 2 As shown, a first die 220 may be disposed on a substrate 210, and a first adhesive layer 230 may be disposed between the first die 220 and the substrate 210, so that the first die 220 can be fixed to the substrate 210. In some embodiments, the first adhesive layer 230 may contain a material with adhesive properties, such as, but not limited to, a wafer bonding film or a resin layer. A second die 240 is disposed on the first die 220, and a second adhesive layer 250 may be disposed between the second die 240 and the first die 220, so that the second die 240 can be fixed to the first die 220. In some embodiments, the second adhesive layer 250 may contain a material with adhesive properties, such as, but not limited to, a wafer bonding film or a resin.

[0016] In this embodiment, the second die 240 may include at least one functional circuit, and thus can perform at least one specific function when powered on. For example, the second die 240 may include memory, a controller, a processor, an amplifier, a filter, a boost circuit, a buck circuit, or other functional circuits, and thus can perform the corresponding function when powered on. In this document, for the sake of understanding and simplicity, this die with functional circuitry, such as the second die 240, may also be referred to as a functional die. Furthermore, the second die 240 may also include solder pads for external connections.

[0017] Specifically, the second die 240 may have a first surface 240A and a second surface 240B. The first surface 240A of the second die 240 may be in contact with the second adhesive layer 250, while the second surface 240B may have at least one solder pad 242. In this embodiment, the package structure 200 may also include lead pads 260 and bonding wires 270. The bonding wires 270 may be, for example, but not limited to, gold wires or copper wires. Furthermore, the bonding wires 270 may connect the solder pads 242 to the lead pads 260 by wire bonding. In some embodiments, the base 210 and the lead pads 260 may be part of the lead frame in the package structure 200.

[0018] In some embodiments, the first die 220 may be, for example, a dummy die relative to the second die 240. For instance, the first die 220 may not contain any circuitry with substantial function or purpose. In this embodiment, the first die 220 may be insulating, thus providing insulation between the second die 240 and the substrate 210. In other words, the second die 240 may be insulated from the substrate 210 at least through the first die 220. In some embodiments, the resistivity of the first die 220 may be, for example, greater than 100 ohms / cm. For example, the first die 220 may be an undoped or low-doped silicon die. Furthermore, in some embodiments, the first adhesive layer 230 and the second adhesive layer 250 may also be insulating, thus further ensuring insulation between the second die 240 and the substrate 210.

[0019] Since the package structure 200 can utilize the redundant die 220 as an insulating layer between the functional die 240 and the package substrate 210, it provides a more effective and stable insulation effect between the functional die 240 and the package substrate 210 compared to simply using an adhesive layer to provide insulation. Furthermore, since the redundant die 220 provides good insulation, there is no need to perform additional precision semiconductor processing on the functional die 240 to form an extra insulating layer, thus simplifying the manufacturing process of the package structure 200.

[0020] Figure 3 This is a schematic diagram of a packaging structure 300 according to an embodiment of this application. The difference between packaging structure 300 and packaging structure 100 is that packaging structure 300 may further include a third die 380 and a third adhesive layer 390. For example... Figure 1 As shown, the third die 380 can be disposed on the base 210, and the third adhesive layer 390 can be disposed between the third die 380 and the base 210, so that the third die 380 can be fixed on the base 210. In this embodiment, the third die 380 can be electrically connected to the base 210 through the third adhesive layer 390. In other words, the third adhesive layer 390 can be conductive and can couple the third die 380 to the base 210. The third adhesive layer 390 can be, for example, a conductive adhesive or a conductive resin. In this embodiment, since the first die 220 can provide a reliable insulation effect between the second die 240 and the base 210, the encapsulation structure 300 can also include a third die 380 electrically connected to the base 210, so as not to create a short circuit between the second die 240 and the third die 380 through the base 210.

[0021] Figure 4 This is a flowchart of a packaging method M1 according to an embodiment of this application. In some embodiments, the packaging method M1 can be used to manufacture... Figure 2 The packaging structure is 200. Figures 5A to 5H This is a cross-sectional view of one or more stages of manufacturing a packaging structure 200 according to packaging method M1 in an embodiment of this application.

[0022] Figure 4 Method M1 may include steps S110 to S170, but is not limited to Figure 4 Execute in the order shown. Figure 5A As shown, in step S110, a lead frame including a base 210 and a pin pad 260 can be obtained.

[0023] In step S120, as Figure 5B As shown, the wafer 22 containing the first die 220 can be diced to obtain the first die 220. In some embodiments, to meet the thickness requirements of the packaging structure 200, the wafer 22 can be thinned before dicing; however, this application is not limited thereto.

[0024] In step S130, the resin layer can be applied to the base 210 as the first adhesive layer 230, such as... Figure 5C As shown; and the first grain 220 can be placed on the first adhesive layer 230 before the first adhesive layer 230 has cured, as shown. Figure 5D As shown. In this way, the first grain 220 can be fixed to the base 210 through the first adhesive layer 230.

[0025] In step S140, as Figure 5E As shown, the wafer 24 containing the second grain 240 can be diced to obtain the second grain 240. In step S150, a resin layer can be applied as a second adhesive layer 250 onto the first grain 220, such as... Figure 5F As shown; and before the second adhesive layer 250 has cured, the second grain 240 is placed on the second adhesive layer 250, as shown. Figure 5G As shown. In this way, the second grain 240 can be fixed to the first grain 220 through the second adhesive layer 250.

[0026] In step S160, the bonding wire 270 can be connected between the solder pad 242 and the lead pad 260 by wire bonding, as shown below. Figure 5H As shown. Next, in step S170, the first grain 220, the first adhesive layer 230, the second grain 240, the second adhesive layer 250, and the bonding wire 270 can be further molded onto the lead frame to form a... Figure 2 The packaging structure 200 is shown.

[0027] In this embodiment, the first adhesive layer 230 may be a resin layer; however, this application is not limited thereto. In some embodiments, before dicing the wafer 22, a wafer adhesive film may be bonded to the wafer 22, and the wafer adhesive film may be used as the first adhesive layer 230.

[0028] Figure 6 This is a schematic cross-sectional view of a wafer being diced to obtain a first die 220 according to an embodiment of this application. Figure 7 This is a schematic cross-sectional view showing the first grain 220 fixed to the base 210 by the first adhesive layer 230. (See diagram below.) Figure 6 As shown, before dicing wafer 22, wafer bonding film 230A can be bonded to wafer 22. In this way, when wafer 22 is diced, wafer bonding film 230A will also be diced, thereby obtaining the first die 220 and a portion of the wafer bonding film bonded to the first die 220. In this embodiment, the portion of the wafer bonding film bonded to the first die 220 can serve as the first bonding layer 230, therefore... Figure 7 In this process, the first die 220 can be directly fixed to the substrate 210 using the partial wafer bonding film (i.e., the first bonding layer 230) bonded to the first die 220, without the need for an additional resin layer. In other words, Figure 5B , 5C The steps shown in 5D can be derived from... Figure 6 and Figure 7 The steps shown are replaced.

[0029] Similarly, the second adhesive layer 250 can also be implemented using a wafer bonding film. That is, before dicing the wafer 24, the wafer bonding film can be bonded to the wafer 24. In this way, after dicing the wafer 24 and the wafer bonding film, the second die 240 and a portion of the wafer bonding film bonded to the second die 240 can be obtained, and the portion of the wafer bonding film bonded to the second die 240 can be used as the second adhesive layer 250, thereby fixing the second die 240 onto the first die 220.

[0030] In some embodiments, method M1 can also be used to manufacture package structure 300. In this case, the third die 380 can be utilized with... Figure 5B , 5C Similar to the steps in 5D, a conductive adhesive material (e.g., conductive adhesive or conductive resin) is used as the third adhesive layer 390 to fix the third grain 380 to the base 210. However, this application is not limited thereto. In some embodiments, the third grain 380 may utilize a conductive adhesive material (e.g., conductive glue or conductive resin) as the third adhesive layer 390 to fix the third grain 380 to the base 210. Figure 6 and Figure 7A similar process is followed, in which a conductive wafer bonding film is bonded to the wafer containing the third die 380, and then the wafer is diced. In this way, the wafer bonding film can be used as the third adhesive layer 390 to fix the third die 380 to the substrate 210.

[0031] In summary, the packaging structure and method provided by the embodiments of this application utilize redundant dies as an insulating layer between the functional die and the packaging substrate. Therefore, compared to simply using an adhesive layer to provide insulation, the packaging structure and method provided by the embodiments of this application can provide a more effective and stable insulation effect between the functional die and the packaging substrate. Furthermore, since redundant dies can provide good insulation, there is no need to perform additional precision semiconductor processes on the functional die or the wafer containing the functional die to form an additional insulating layer, thus simplifying the overall process.

[0032] Symbol Explanation

[0033] 100, 200, 300: Package structure

[0034] 110: Base

[0035] 120: Grain

[0036] 122: Welding pad

[0037] 130: Adhesive layer

[0038] 140: Pin pad

[0039] 150: Joint line

[0040] MD1: Encapsulation layer

[0041] 210: Base

[0042] 220, 240, 380: Grain size

[0043] 230, 250, 390: Adhesive layer

[0044] 240A: First Page

[0045] 240B: Second side

[0046] 242: Welding pad

[0047] 260: Pin pad

[0048] 270: Joint line

[0049] M1: Method

[0050] S110, S120, S130, S140, S150, S160, S170: Steps 22, 24: Wafer

[0051] 230A: Wafer bonding film

Claims

1. A packaging structure comprising: A base; A first grain is disposed on the base; A first adhesive layer is disposed between the first grain and the base to fix the first grain onto the base; A second die, configured to perform at least one specific function when powered on, the second die being disposed on the first die; and A second adhesive layer is disposed between the second grain and the first grain to fix the second grain onto the first grain; The second grain is insulated from the base at least through the first grain.

2. The packaging structure as claimed in claim 1, wherein the resistivity of the first die is greater than 100 ohms / cm.

3. The packaging structure of claim 1, wherein the first adhesive layer comprises a wafer bonding film or a resin layer.

4. The packaging structure of claim 1, wherein the second adhesive layer comprises a wafer bonding film or a resin layer.

5. The packaging structure of claim 1, wherein the second die has a first surface and a second surface, the first surface is in contact with the second adhesive layer, and the second surface has a solder pad, the packaging structure further includes a lead pad and a bonding wire, the bonding wire being coupled to the solder pad and the lead pad.

6. The packaging structure as described in claim 1, further comprising: A third grain is disposed on the base; and A third adhesive layer is disposed between the third grain and the base to fix the third grain onto the base and to electrically connect the third grain to the base.

7. An encapsulation method, comprising: Acquire a base; A first grain was obtained; The first grain is fixed to the base by a first adhesive layer; Obtain a second die, wherein the second die is used to perform at least one specific function when powered on; and The second grain is fixed to the first grain by a second adhesive layer; The second grain is insulated from the base at least through the first grain.

8. The method of claim 7, wherein the resistivity of the first grain is greater than 100 ohms / cm.

9. The method of claim 7, further comprising: A wafer bonding film is bonded to a first wafer containing the first grain; The step of obtaining the first grain includes cutting the first wafer and the wafer bonding film to obtain the first grain and a portion of the wafer bonding film bonded to the first grain; and The step of fixing the first grain onto the base using the first adhesive layer includes using the portion of the wafer bonding film as the first adhesive layer to fix the first grain onto the base.

10. The method of claim 7, further comprising: A resin layer is applied to the base; The step of obtaining the first grain includes cutting a first wafer containing the first grain to obtain the first grain; and The step of fixing the first grain onto the base through the first adhesive layer includes using the resin layer as the first adhesive layer and bonding the first grain to the resin layer.

11. The method of claim 7, further comprising: A wafer bonding film is bonded to a second wafer containing the second grain; The step of obtaining the second grain includes cutting the second wafer and the wafer bonding film to obtain the second grain and a portion of the wafer bonding film bonded to the second grain; and The step of fixing the second grain onto the first grain using the second adhesive layer includes using the portion of the wafer bonding film as the second adhesive layer to fix the second grain onto the first grain.

12. The method of claim 7, further comprising: A resin layer is applied to the first grain; The step of obtaining the second grain includes cutting a second wafer containing the second grain to obtain the second grain; and The step of fixing the second grain onto the first grain through the second adhesive layer includes using the resin layer as the second adhesive layer to bond the second grain to the first grain.

13. The method of claim 7, wherein the second grain has a first surface and a second surface, the first surface being in contact with the second adhesive layer, the second surface having a solder pad, and the method further comprising coupling the solder pad to a lead pad by wire bonding.

14. The method of claim 7, further comprising: Receive a first wafer; and This thins the first wafer; The step of obtaining the first grain includes cutting the first wafer to obtain the first grain.

15. The method of claim 7, further comprising: A third grain was obtained; and The third grain is fixed to the base by a third adhesive layer and electrically connected to the base.

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