A multi-layer chip stack package method and structure

Abstract

The present application relates to the technical field of semiconductor packaging, and discloses a multilayer chip stack packaging method and structure, which specifically comprises the following steps: providing a conductive connecting column unit with a bending structure; packaging the conductive connecting column unit after mounting the conductive connecting column unit on a substrate; grinding the packaged assembly to expose the end of the conductive connecting column unit away from the substrate; and stacking at least one chip on the exposed conductive connecting column unit, wherein the bending structure of the conductive connecting column unit enables the stacking of multiple chips in the same plane layer. The present application can realize efficient stacking of multiple chips in the same plane layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, in particular to a multilayer chip stacking packaging method and structure thereof. BACKGROUND

[0002] With the increasing demand for miniaturization and high integration of electronic devices, chip stacking packaging technology has become an important way to achieve high-density integration. Existing chip stacking technologies mainly include through-silicon via technology and wire bonding methods, but these technologies have obvious deficiencies when dealing with stacking chips of different sizes.

[0003] Traditional chip stacking packaging usually requires chips of the same size and is difficult to achieve efficient stacking of multiple chips in the same plane layer. When different size chips need to be stacked, multiple packaging processes are often required, resulting in complex process flow and increased cost.

[0004] Therefore, it is urgent to propose a multilayer chip stacking packaging method and structure to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a multilayer chip stacking packaging method and structure that can achieve efficient stacking of multiple chips in the same plane layer.

[0006] To solve the above technical problems, the present application provides a multilayer chip stacking packaging method, which specifically includes the following steps:

[0007] A conductive connecting column unit with a bending structure is provided;

[0008] After the conductive connecting column unit is installed on the substrate, the conductive connecting column unit is encapsulated;

[0009] The encapsulated assembly is ground to expose the end of the conductive connecting column unit away from the substrate; and

[0010] At least one chip is stacked on the exposed conductive connecting column unit, wherein the bending structure of the conductive connecting column unit allows multiple chips to be stacked in the same plane layer.

[0011] Further, the conductive connecting column unit with a bending structure is provided, specifically including: first, placing conductive material in the slot of the die to make a conductive connecting column; then cutting the conductive connecting column into individual conductive connecting column units through a stamping process; installing the conductive connecting column units on the bottom plate to form an assembly; and then installing the assembly on the substrate.

[0012] Further, the mounting of the conductive connecting column unit on the bottom plate to form an assembly specifically comprises: placing the conductive connecting column unit in a layout module; fixing the conductive connecting column unit on the bottom plate by using an adhesive; curing the adhesive; cleaning the assembly; and drying the cleaned assembly.

[0013] Further, the adhesive comprises a hydrolytic glue or an epoxy resin-based glue.

[0014] Further, the grinding of the encapsulated assembly specifically comprises: grinding the end of the assembly away from the substrate, removing the bottom plate, and exposing the end of the conductive connecting column unit.

[0015] Further, the stacking of at least one chip on the exposed conductive connecting column unit specifically comprises: applying a soldering material to the end of the exposed conductive connecting column unit and performing a pre-soldering process; performing a ball planting process on the end of the conductive connecting column unit after the pre-soldering process to form a solder ball structure for chip connection.

[0016] Further, the stacking of at least one chip on the exposed conductive connecting column unit specifically further comprises: stacking the chip on the conductive connecting column unit by using a flux coating method; and connecting and fixing the chip and the conductive connecting column unit by a heat treatment process.

[0017] In addition, the present application also proposes a multi-layer chip stack package structure made by using the multi-layer chip stack packaging method as described above, comprising:

[0018] a substrate;

[0019] a conductive connecting column unit with a bending structure, which is mounted on the substrate;

[0020] an encapsulation layer, which surrounds the substrate and the conductive connecting column unit, so that the end of the conductive connecting column unit is exposed from the encapsulation layer; and

[0021] at least one chip, which is stacked on the end of the exposed conductive connecting column unit;

[0022] The bending structure of the conductive connecting column unit enables multiple chips to be stacked in the same plane layer.

[0023] Further, the conductive connecting column unit comprises a Z-shaped structure or an L-shaped structure.

[0024] Further, the material of the conductive connecting column unit comprises at least one of copper, aluminum or silver.

[0025] By the technical scheme, the application has the following beneficial effects:

[0026] By adopting the conductive connecting column unit with the bending structure, and exposing the end of the conductive connecting column unit after the packaging treatment and grinding after the conductive connecting column unit is installed on the substrate, the chips are stacked on the exposed conductive connecting column unit, and the technical effect that multiple chips can be stacked in the same plane layer is achieved. This method simplifies the packaging process flow, avoids multiple plastic packaging treatment, improves the packaging efficiency, and the bending structure of the conductive connecting column unit makes the electrical interconnection path more reasonable, and improves the signal transmission performance.

[0027] The conductive connecting column unit is made by a die stamping process, and a Z-shaped or L-shaped structure design is adopted, so that the packaging structure is more compact, and is suitable for the stacking needs of chips of different sizes. At the same time, by using hydrolytic glue or epoxy resin glue to fix the connecting column, and combining the flux coating and heat treatment process to connect and fix the chip and the conductive connecting column unit, the reliability and stability of the packaging structure are further improved, and the needs of high-density integrated circuit packaging are met. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A flowchart of a multilayer chip stacking packaging method in an embodiment of the application;

[0029] Figure 2 A structural schematic diagram of a multilayer chip stacking packaging structure in an embodiment of the application;

[0030] Figure 3 A structural schematic diagram of a conductive connecting column unit made by a die upper groove in a multilayer chip stacking packaging structure in an embodiment of the application;

[0031] Figure 4 A structural schematic diagram of the installation of a conductive connecting column unit and a bottom plate in a multilayer chip stacking packaging structure in an embodiment of the application;

[0032] Figure 5 A structural schematic diagram of a conductive connecting column unit and a bottom plate forming an assembly in a multilayer chip stacking packaging structure in an embodiment of the application;

[0033] Figure 6 A structural schematic diagram of an assembly installed on a substrate in a multilayer chip stacking packaging structure in an embodiment of the application;

[0034] Figure 7 A structural schematic diagram of an assembly on a substrate in a multilayer chip stacking packaging structure in an embodiment of the application;

[0035] Figure 8 A structural schematic diagram of an assembly after packaging in a multilayer chip stacking packaging structure in an embodiment of the application;

[0036] Figure 9 Fig. 2 is a structural schematic diagram of the ball planting on the exposed end of the conductive connecting column unit in the multilayer chip stack packaging structure of an embodiment of the present application;

[0037] Figure 10 Fig. 3 is a structural schematic diagram of the ball planting on the side of the substrate away from the conductive connecting column in the multilayer chip stack packaging structure of an embodiment of the present application;

[0038] Figure 11 Fig. 4 is a structural schematic diagram of the superposition of another substrate on the side of the substrate away from the conductive connecting column in the multilayer chip stack packaging structure of an embodiment of the present application.

[0039] In the figure, 1 is a conductive connecting column unit; 2 is a bottom plate; 3 is a substrate; 4 is a packaging layer; 5 is a chip; 100 is a mold upper groove. DETAILED DESCRIPTION

[0040] Based on the inspiration of the present specification, the person skilled in the art can form new technical solutions by cross combination of different embodiments without causing technical contradiction, and such variations should be considered to fall within the protection scope of the present solution.

[0041] A multilayer chip stack packaging method and structure of the present application will be described in more detail below with reference to the accompanying drawings, in which a preferred embodiment of the present application is represented, and it should be understood that the person skilled in the art can modify the present application described herein while still achieving the advantageous effects of the present application. Therefore, the following description should be understood as extensive knowledge for the person skilled in the art, and not as a limitation on the present application.

[0042] The present application will be described in more detail below with reference to the accompanying drawings in the following paragraphs by way of example. The advantages and features of the present application will be more apparent according to the following description. It should be noted that the drawings are all in a very simplified form and all use non-precise proportions, only to facilitate, clearly assist the purpose of illustrating the embodiments of the present application.

[0043] As shown in Fig. 1, the present embodiment proposes a convenient and practical multilayer chip stack packaging method, which specifically includes the following steps: Figures 1-11

[0044] S1, providing a conductive connecting column unit 1 with a bent structure;

[0045] S2, installing the conductive connecting column unit 1 on a substrate 3 and then performing packaging treatment on the conductive connecting column unit 1;

[0046] S3, grinding the packaged assembly to expose the end of the conductive connecting column unit 1 away from the substrate 3; and

[0047] ​S4, stacking at least one chip 5 on the exposed conductive stud unit 1, wherein the bending structure of the conductive stud unit 1 enables stacking of multiple chips 5 in the same plane layer.

[0048] In step S1, the conductive stud unit 1 with a bending structure is provided, specifically including: first, placing conductive material into the slot 100 of the die to make a conductive stud; then, cutting the conductive stud into individual conductive stud units 1 through a stamping process; installing the conductive stud unit 1 on the bottom plate 2 to form an assembly; and then installing the assembly on the substrate 3.

[0049] In step S2, the conductive stud unit 1 is installed on the bottom plate 2 to form an assembly, specifically including: placing the conductive stud unit 1 in a layout module; using an adhesive to fix the conductive stud unit 1 on the bottom plate 2; curing the adhesive; cleaning the assembly; and drying the cleaned assembly. The cleaning process can remove impurities and residues on the surface of the assembly, and the drying process ensures the effectiveness of the subsequent packaging process. In a specific example, the cleaning process can use ultrasonic cleaning technology, immersing the assembly in a cleaning solution, and removing surface contaminants through ultrasonic vibration; the drying process can be carried out in a constant temperature environment at a preset temperature, with the time controlled within a preset time range to ensure complete drying of the assembly. These processing steps can improve packaging quality and product reliability.

[0050] In this embodiment, the adhesive includes hydrolytic glue or epoxy-based glue. Specifically, hydrolytic glue has good fluidity and permeability, suitable for bonding of fine structures; epoxy-based glue has high mechanical strength and heat resistance, suitable for use in high temperature environments. Selecting different types of adhesives according to actual application environments enhances the adaptability and reliability of the packaging structure. In a specific example, when the packaging structure needs to work in a high temperature environment, epoxy-based glue with a temperature resistance range of -40°C to 150°C can be selected; when the bonding strength requirement is not high but a faster curing speed is needed, hydrolytic glue can be selected. As known by those skilled in the art, the selection of adhesive can be adjusted according to actual needs, and the adhesive also includes other types in addition to this embodiment.

[0051] In step S3, the packaged assembly is ground, specifically including: grinding the end of the assembly away from the substrate 3, removing the bottom plate 2, and exposing the end of the conductive stud unit 1.

[0052] In step S4, the at least one chip 5 is stacked on the exposed conductive stud unit 1, specifically including: applying soldering material on the end of the exposed conductive stud unit 1 and performing pre-soldering treatment; and performing ball planting treatment on the end of the conductive stud unit 1 after the pre-soldering treatment to form a solder ball structure for connecting the chip 5.

[0053] Further, in step S4, the at least one chip 5 is stacked on the exposed conductive stud unit 1, specifically further including: stacking the chip 5 on the conductive stud unit 1 by using flux coating; and connecting and fixing the chip 5 and the conductive stud unit 1 by a heat treatment process. The use of flux improves the wettability of the soldering interface, and the heat treatment process makes the soldering material form a firm metallurgical bond with the chip 5 and the conductive stud unit 1. In a specific example, the flux can be uniformly coated on the end of the conductive stud unit 1 by screen printing or spraying; the heat treatment process can be performed by using a reflow soldering device, and the temperature curve is designed as follows: preheating at 150°C for 60 seconds, soldering at 220°C for 30 seconds, and then naturally cooling to room temperature. This processing method improves the soldering quality and connection reliability. The specific parameters can be set according to the actual situation.

[0054] In addition, continuing to refer to Figures 2-11 The present embodiment also proposes a multi-layer chip 5 stacking packaging structure, which is made by using the multi-layer chip 5 stacking packaging method as described above, and includes: a substrate 3; a conductive stud unit 1 with a bending structure, which is installed on the substrate 3; a packaging layer 4, which is formed around the substrate 3 and the conductive stud unit 1, so that the end of the conductive stud unit 1 is exposed from the packaging layer 4; and at least one chip 5, which is stacked on the exposed end of the conductive stud unit 1; the bending structure of the conductive stud unit 1 enables multiple chips 5 to be stacked in the same plane layer.

[0055] Preferably, the conductive connecting column unit 1 comprises a Z-shaped structure or an L-shaped structure. Specifically, the Z-shaped conductive connecting column unit 1 has two bending positions, forming a ladder-like structure similar to the English letter "Z", which is suitable for connecting two points with a relatively long distance; the L-shaped conductive connecting column unit 1 has one bending position, forming an "L" shape, which is suitable for connecting two points in the vertical direction. In a specific example, when it is necessary to connect two adjacent chips 5 in the same plane layer, the Z-shaped conductive connecting column unit 1 can be used, and the bending angle can be designed to be bent twice at 90 degrees, forming a vertical-horizontal-vertical connection path; when it is necessary to connect chips 5 of different heights, the L-shaped conductive connecting column unit 1 can be used, and the bending angle is designed to be bent once at 90 degrees. The conductive connecting column unit 1 with different structures can adapt to different packaging needs, enhancing the flexibility and adaptability of the packaging structure.

[0056] In an embodiment, the material of the conductive connecting column unit 1 comprises at least one of copper, aluminum or silver. Specifically, copper has good electrical conductivity and cost advantage, and is a commonly used conductive material; aluminum has a relatively light weight and good heat dissipation performance; silver has the best electrical conductivity but is relatively high in cost. Different materials can be selected according to different application scenarios to improve the performance and cost-effectiveness ratio of the conductive connecting column unit 1. In a specific example, when the packaging structure is used for ordinary consumer electronic products, a copper material with a relatively low cost can be selected; when used for portable devices that need to be lightweight, an aluminum material can be selected; when used for high-performance computing devices or aerospace fields, a silver material or a copper-silver composite material with better electrical conductivity can be selected. Those skilled in the art can know that the material of the conductive connecting column unit 1 can be set according to actual needs, and the material also includes other materials or alloys other than the embodiment.

[0057] In the present embodiment, the working principle of the conductive connecting column unit 1 is to provide sufficient height in the vertical direction to accommodate the thickness of the packaging layer 4 through its special bending structure, while extending to the contact point position of the chip 5 in the horizontal direction. After the packaged assembly is subjected to polishing treatment, the end of the conductive connecting column unit 1 is exposed from the surface of the packaging layer 4, forming a contact point connected to the chip 5. A plurality of conductive connecting column units 1 with different bending structures can be connected to different positions of the chip 5, realizing the parallel stacking of multiple chips 5 in the same plane layer. This arrangement can improve the interconnection density between the chips 5, reduce the signal transmission path, and improve the electrical performance.

[0058] In summary, the multi-layer chip stacking packaging method and structure proposed by the present application have the following advantages:

[0059] By adopting the conductive connecting column unit with the bending structure, and after installing it on the substrate, and then through the packaging treatment and grinding to expose the end of the conductive connecting column unit, and stacking the chip on the exposed conductive connecting column unit, the technical effect that multiple chips can be stacked in the same plane layer is realized. This method simplifies the packaging process, avoids multiple plastic packaging treatment, improves the packaging efficiency, and the bending structure of the conductive connecting column unit makes the electrical interconnection path more reasonable, and improves the signal transmission performance.

[0060] The conductive connecting column unit is made by a die stamping process, and a Z-shaped or L-shaped structure design is adopted, so that the packaging structure is more compact, and is suitable for the stacking needs of different size chips. At the same time, by using hydrolytic glue or epoxy resin type glue to fix the connecting column, and combining with the flux coating and heat treatment process to connect and fix the chip and the conductive connecting column unit, the reliability and stability of the packaging structure are further improved, and the needs of high-density integrated circuit packaging are met.

[0061] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method of multi-chip package stacking, comprising: Specifically comprising the following: Providing a conductive connecting column unit with a bending structure, specifically comprising: first, placing conductive material into the groove of the mold to make a conductive connecting column; then cutting the conductive connecting column into a single conductive connecting column unit through a stamping process; installing the conductive connecting column unit on the bottom plate to form an assembly, specifically comprising: placing the conductive connecting column unit in a layout module; using an adhesive to fix the conductive connecting column unit on the bottom plate; curing the adhesive; After installing the conductive connecting column unit on the substrate, the conductive connecting column unit is encapsulated; Grinding the encapsulated assembly to remove the bottom plate, so that the end of the conductive connecting column unit away from the substrate is exposed from the encapsulation layer; and Stacking at least one chip on the exposed conductive connecting column unit, wherein the bending structure of the conductive connecting column unit enables multiple chips to be stacked in the same plane layer.

2. The multi-chip package stacking method of claim 1, wherein, The conductive connecting column unit is installed on the bottom plate to form an assembly, and specifically further comprises: cleaning the assembly; and drying the cleaned assembly.

3. The multi-chip package stacking method of claim 2, wherein, The adhesive includes hydrolytic glue or epoxy resin-based glue.

4. The multi-chip package stacking method of claim 1, wherein, The encapsulated assembly is ground, specifically comprising: grinding the end of the assembly away from the substrate, removing the bottom plate, and exposing the end of the conductive connecting column unit.

5. The multi-chip package stacking method of claim 1, wherein, The at least one chip is stacked on the exposed conductive connecting column unit, specifically comprising: applying soldering material to the exposed end of the conductive connecting column unit and performing pre-soldering treatment; performing ball planting treatment on the end of the conductive connecting column unit after pre-soldering treatment to form a solder ball structure for chip connection.

6. The multi-chip package stacking method of claim 5, wherein, The at least one chip is stacked on the exposed conductive connecting column unit, specifically further comprising: stacking the chip on the conductive connecting column unit using a flux coating method; and connecting and fixing the chip and the conductive connecting column unit through a heat treatment process.

7. A multi-layer chip stack package structure made by the multi-layer chip stack packaging method according to any one of claims 1 to 6, wherein Comprising: a substrate; a conductive connecting column unit with a bending structure, the conductive connecting column unit being installed on the substrate; an encapsulation layer formed around the substrate and the conductive connecting column unit, so that the end of the conductive connecting column is exposed from the encapsulation layer; and at least one chip stacked on the exposed end of the conductive connecting column unit; The bending structure of the conductive connecting column unit enables multiple chips to be stacked in the same plane layer. The conductive connecting column unit includes a Z-shaped structure or an L-shaped structure.

8. The multi-chip package-on-package structure of claim 7, wherein, The material of the conductive connecting column unit includes at least one of copper, aluminum, or silver.

9. The multi-chip package-on-package structure of claim 7, wherein, ​

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