Packaging method and structure of LPCAMM memory module

Abstract

The invention discloses a packaging method and structure of an LPCAMM memory module, and relates to the technical field of memory modules. The method comprises the following steps: cutting an original wafer to obtain a plurality of bare chips; obtaining a carrier substrate, and inversely arranging a plurality of bare chips on the carrier substrate to form a recombined wafer; forming a dielectric layer on the surface of the recombined wafer; a transparent filter membrane is attached to the surface of the dielectric layer; exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern; a rewiring layer is formed at the rewiring pattern through electroplating, and a heat dissipation layer is formed at the heat dissipation pattern through electroplating; cutting the recombined wafer to obtain a plurality of single bare chips after rewiring; obtaining a PCB (Printed Circuit Board), and connecting the bare chip with the PCB to form an LPCAMM memory module; the LPCAMM memory module is connected with the detachable connecting piece, and the detachable connecting piece is detachably connected with the control mainboard. According to the method, the thickness of the LPCAMM memory module can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of memory modules, and in particular to a packaging method and structure of an LPCAMM memory module. Background Art

[0002] With the continuous development and popularization of AI technology, the application scenarios of AI PC (artificial intelligence computer) have become more extensive, and the shipment volume of AI PC is also increasing year by year. Compared with traditional computers, AI PC has higher requirements for convenience and performance. Therefore, the memory module of AI PC needs to be ultra-thin and have a large capacity to have sufficient convenience and performance. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a packaging method and structure of an LPCAMM memory module, which can make the thickness of the LPCAMM memory module thinner to meet the needs of AI PC.

[0004] In a first aspect, according to a packaging method of an LPCAMM memory module according to an embodiment of the present invention, the method comprises the following steps: Cutting the original wafer to obtain a plurality of single bare chips; the bare chip is an LPDDR5x chip, and the bare chip has a pad; Obtaining a carrier substrate, and placing a plurality of the bare chips upside down on the carrier substrate in a preset arrangement to form a reconstructed wafer; forming a dielectric layer on the surface of the reconstructed wafer; A transparent filter membrane is attached to the surface of the medium layer; Exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern, and filtering the exposure light source through the transparent filter film during exposure; Removing the transparent filter film, electroplating to form a redistribution layer at the redistribution pattern, electroplating to form a heat dissipation layer at the heat dissipation pattern, and conducting the redistribution layer with the pad; Cutting the reconstructed wafer to obtain a plurality of single bare chips after rewiring; Obtain a PCB board; the PCB board is provided with a plurality of connection points and a plurality of heat dissipation points; Connecting the rewiring layer of the bare chip after rewiring with the corresponding connection point, and connecting the heat dissipation layer of the bare chip after rewiring with the corresponding heat dissipation point to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

[0005] According to some embodiments of the present invention, the step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point includes: Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; Printing solder paste on the surface of the pad; After the pads are connected to the corresponding connection points, the pads and the connection points are reflowed to connect the bare chip to the PCB board to form the LPCAMM memory module.

[0006] According to some embodiments of the present invention, the step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point includes: Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; After the pad is brought into contact with the corresponding connection point, the pad and the corresponding connection point are subjected to thermal compression welding to connect the bare chip with the PCB board to form the LPCAMM memory module. According to some embodiments of the present invention, the step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point includes: implanting bumps at predetermined positions of the redistribution layer; The redistribution layer is connected to the corresponding connection points through the bumps, so that the bare chip is connected to the PCB board through the redistribution layer to form the LPCAMM memory module. According to some embodiments of the present invention, the step of implanting bumps at preset positions of the redistribution layer includes: Attaching a photosensitive dry film on the surface of the dielectric layer; exposing and developing the photosensitive dry film to form a window at the preset position; Forming the bump at the window by electroplating; The photosensitive dry film is removed.

[0007] According to some embodiments of the present invention, the step of connecting the LPCAMM memory module to a detachable connector and detachably connecting the detachable connector to a control mainboard includes: Setting a compression connection interface of the CAMM standard for the LPCAMM memory module; The LPCAMM memory module is connected to the detachable connector via the compression connection interface; The detachable connecting piece is detachably connected to the control main board.

[0008] According to some embodiments of the present invention, the step of exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern, and filtering the exposure light source through the transparent filter film during exposure, comprises: Filtering out light sources with wavelengths lower than a preset threshold in the exposure light source through the transparent filter film; Exposing the dielectric layer through the filtered exposure light source; The exposed dielectric layer is developed to form the redistribution pattern and the heat dissipation pattern.

[0009] In a second aspect, a packaging method of an LPCAMM memory module according to an embodiment of the present invention comprises the following steps: Cutting the original wafer to obtain a plurality of single bare chips; the bare chip is an LPDDR5x chip, and the bare chip has a pad; Get the PCB board; Rewiring the circuits of the PCB board according to the positions of the soldering pads so that the connection points of the PCB board correspond to the soldering pads one by one; implanting a bump on the pad; Connecting the pads to the corresponding connection points through the bumps, so that the bare chip is connected to the PCB board to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

[0010] In a third aspect, according to a packaging method of an LPCAMM memory module according to an embodiment of the present invention, the method comprises the following steps: The original wafer is cut to obtain a plurality of single bare chips; the bare chips are LPDDR5x chips; Disposing a first pad on the bare chip; Get the PCB board; Rewiring the circuit of the PCB board according to the position of the first pad, and providing a second pad corresponding to the first pad on the PCB board; Placing the bare chip on the PCB board and making the first pad contact the second pad; Performing thermal compression welding or SMT on the first pad and the second pad to connect the bare chip to the PCB board to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

[0011] In a fourth aspect, the packaging structure of the LPCAMM memory module according to an embodiment of the present invention is manufactured by the packaging method of the LPCAMM memory module described in the first aspect, the second aspect, or the third aspect.

[0012] The packaging method and structure of the LPCAMM memory module according to the embodiment of the present invention have at least the following beneficial effects: by rewiring the bare chip and then directly connecting the bare chip to the PCB board, the size of the final packaging structure is smaller, which can reduce the thickness of the LPCAMM memory module, thereby meeting the ultra-thin requirements of AI PC.

[0013] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A schematic diagram of the packaging structure of the LPCAMM memory module according to an embodiment of the present invention; Figure 2 A schematic diagram of a packaging structure of an LPCAMM memory module according to an embodiment of the present invention; Figure 3 A flowchart of a method for packaging an LPCAMM memory module according to an embodiment of the present invention; Figure 4 A schematic diagram of a packaging structure of an LPCAMM memory module according to another embodiment of the present invention; Figure 5 A flowchart of a packaging method for an LPCAMM memory module according to another embodiment of the present invention; Figure 6 This is a flow chart of the steps of a packaging method for an LPCAMM memory module according to another embodiment of the present invention. DETAILED DESCRIPTION Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limitations on the present application. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0015] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0016] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present invention and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0017] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0018] The following is an explanation of the terms that appear in this application: DIMM: Dual In-line Memory Module, is a common type of memory module, which is mainly used in desktop computers, workstations, servers and other systems.

[0019] SODIMM: Small Outline Dual In-line Memory Module, a small dual in-line memory module, is a memory module specially designed for space-constrained environments such as laptops, small desktops and embedded systems.

[0020] AI PC: AI Personal Computer, that is, a personal computer with built-in artificial intelligence functions. AI PC integrates hardware such as NPU (neural network processor), CPU (central processing unit), GPU (graphics processing unit), and supporting software to achieve the goal of efficient local operation of artificial intelligence applications. This type of computer not only improves the performance and efficiency of personal computers, but also greatly enriches its application scenarios, such as graphic visual processing, semantic understanding, and intelligent interaction.

[0021] LPCAMM: A new removable and modular LPDDR (Low Power Double Data Rate) memory standard.

[0022] LPDDR5X: Low Power Double Data Rate 5X is an upgraded version of LPDDR5, with higher bandwidth, lower power consumption and stronger performance, supporting the next generation of leading low-power DRAM. It is not only widely used in the mobile field, but also leads the low-power DRAM market, providing new power for high-performance PCs, servers and vehicles.

[0023] RDL: Redistribution Layer, rewiring technology, which can form new metal lines on the wafer to connect the original aluminum pads and new bumps or gold pads, thereby realizing line redistribution. SMT: Surface Mount Technology, surface mount technology, prepares for the welding of components by printing solder paste or patch glue onto the pads of the PCB.

[0024] With the continuous development and popularization of AI technology, the application scenarios of AI PC (artificial intelligence computer) have become more extensive, and the shipment volume of AI PC is also increasing year by year. Compared with traditional computers, AI PC has higher requirements for convenience and performance. Therefore, the memory module of AI PC needs to be ultra-thin and have a large capacity to have sufficient convenience and performance.

[0025] At present, common memory modules are usually in the form of DIMM or SODIMM memory bars. However, although DIMM and SODIMM can meet the needs of general desktop computers or laptops, for AI PCs, DIMM and SODIMM are large in size and thick in thickness, and cannot meet the AI ​​PC's requirements for thinness and large capacity. In order to meet the needs of AI PCs, in this application, LPCAMM memory modules are used as AI PC memory bars, and on this basis, the packaging method of LPCAMM memory modules is changed to further reduce the thickness of LPCAMM memory modules.

[0026] In the prior art, the packaging form of LPCAMM memory module is as follows Figure 1As shown, a bare chip is placed on a substrate 100, wired by bonding technology, the bare chip and the substrate 100 are connected by bonding wires 120, and then the bare chip is packaged by a plastic packaging material 130. For this packaging form, since wire bonding is required and the bare chip needs to be packaged by a plastic packaging material 130, the thickness of the final packaging structure will be relatively large, which cannot meet the requirements of ultra-thinness.

[0027] To this end, in this application, a packaging structure of an LPCAMM memory module is proposed. Figure 2 As shown, the package structure includes a bare chip 300 and a PCB board 200. Among them, in order to meet the requirements of AI PC, the bare chip 300 used in the LPCAMM memory module is an LPDDR5x chip, which has a higher storage capacity and supports a larger data transmission rate and better storage bandwidth. The bare chip 300 is provided with a pad for electrically connecting to the PCB board 200. In order to achieve the connection between the bare chip 300 and the PCB board 200, a bump 400 is provided between the pad and the PCB board 200, and the bare chip 300 and the PCB board 200 are connected by the bump 400. It should be noted that since the pad of the bare chip 300 is directly connected to the PCB board 200 through the bump 400, it is necessary to rewire the circuit of the PCB board 200 according to the layout of the pad of the bare chip 300, so that the connection point of the circuit of the PCB board 200 can correspond one-to-one with the pad of the bare chip 300, so that the direct connection between the two can be achieved.

[0028] According to the packaging structure of the LPCAMM memory module of the embodiment of the present application, the bare chip 300 is directly connected to the PCB board 200 through the bump 400, and the size of the bump 400 is usually very small. Figure 1 The package structure shown, Figure 2 The packaging structure shown can reduce the thickness of the LPCAMM memory module, thereby meeting the ultra-thin requirements of AI PCs.

[0029] like Figure 3 As shown, based on Figure 2 The packaging structure of the LPCAMM memory module is shown. The present application proposes a packaging method of the LPCAMM memory module, which includes the following steps: Step S100: cutting the original wafer to obtain a plurality of single bare chips 300; Step S200: obtaining a PCB board 200; Step S300: rewiring the circuits of the PCB board 200 according to the positions of the solder pads, so that the connection points of the PCB board 200 correspond to the solder pads one by one; Step S400: implanting a bump 400 on the pad; Step S500: Connect the solder pads to the corresponding connection points through the bumps 400, so that the bare chip 300 is connected to the PCB board 200 to form an LPCAMM memory module; Step S600: Connect the LPCAMM memory module to the detachable connector, and detachably connect the detachable connector to the control mainboard.

[0030] First, a plurality of bare chips 300 are arranged on the original wafer, and a single bare chip 300 can be obtained by cutting the original wafer. Then, the RDL technology needs to be used to rewire the PCB board 200 so that the layout of the connection points on the PCB board 200 is completely consistent with the layout of the pads of the bare chip 300. Subsequently, a bump 400 is implanted on the pad, and the connection between the pad and the connection point is achieved through the bump 400, so that the bare chip 300 can be directly placed on the PCB board 200 and connected to the PCB board 200 to form an LPCAMM memory module. Among them, the LPCAMM memory module adopts the compression connection interface of the CAMM standard (Compression Attached Memory Module, compression attached memory module), with strict specifications and short tracking length to achieve modular and interchangeable LPDDR5 memory. The LPCAMM memory module is connected to a detachable connector through a compression connection interface, and the detachable connector is detachably connected to the control motherboard, making the plugging and unplugging of the LPCAMM memory module more convenient.

[0031] According to the packaging structure of the LPCAMM memory module of the embodiment of the present application, the bare chip 300 is directly connected to the PCB board 200 through the bump 400, and the size of the bump 400 is usually very small, thereby reducing the thickness of the LPCAMM memory module and meeting the ultra-thin and large-capacity requirements of the AI ​​PC.

[0032] Furthermore, the present application embodiment also proposes another packaging structure of LPCAMM memory module, such as Figure 4As shown, the package structure includes a bare chip 300 and a PCB board 200. In order to meet the requirements of AI PC, the bare chip 300 used in the LPCAMM memory module is an LPDDR5x chip, which has a higher storage capacity and supports a larger data transmission rate and better storage bandwidth. The bare chip 300 is provided with a first pad 310, and the PCB board 200 is provided with a second pad 210. The first pad 310 corresponds to the second pad 210 one by one. Through the connection between the first pad 310 and the second pad 210, the bare chip 300 and the PCB board 200 can be connected. It should be noted that since the first pad 310 of the bare chip 300 is directly connected to the second pad 210 of the PCB board 200, it is necessary to rewire the circuit of the PCB board 200 according to the layout of the first pad 310 of the bare chip 300, so that the second pad 210 of the PCB board 200 can correspond to the first pad 310 of the bare chip 300 one by one, so that the direct connection between the two can be achieved. The bare chip 300 is placed on the PCB board 200 so that the first pad 310 is in contact with the second pad 210, and then the first pad 310 is heated and pressurized to bond with the second pad 210 by thermal compression welding, thereby achieving the connection between the bare chip 300 and the PCB board 200. In addition to the thermal compression welding, the SMT technology can also be used to achieve the connection between the first pad 310 and the second pad 210, that is, solder paste is printed on the first pad 310, and then the first pad 310 is in contact with the second pad 210, and then reflow soldering is performed to achieve the bonding between the first pad 310 and the second pad 210.

[0033] It should be noted that compared with Figure 2 In the package structure shown, although the size of the bump 400 is small, the thickness can be reduced. Figure 4 The package structure shown directly uses the first pad 310 and the second pad 210 for connection, which can achieve an effect of being smaller than the size of the bump 400, thereby further reducing the thickness of the LPCAMM memory module.

[0034] According to the packaging structure of the LPCAMM memory module of the embodiment of the present application, the bare chip 300 is directly connected to the PCB board 200 through the first pad 310 and the second pad 210, which can reduce the thickness of the LPCAMM memory module, thereby meeting the ultra-thin requirements of AI PC.

[0035] like Figure 5 As shown, based on Figure 3 The packaging structure of the LPCAMM memory module shown in the figure, the present application also proposes another packaging method of the LPCAMM memory module, the method comprising the following steps: Step S110: cutting the original wafer to obtain a plurality of single bare chips 300; Step S121: Disposing a first pad 310 on the bare chip 300; Step S131: Obtain the PCB board 200; Step S141: rewiring the circuit of the PCB board 200 according to the position of the first pad 310, and setting a second pad 210 corresponding to the first pad 310 on the PCB board 200; Step S151: placing the bare chip 300 on the PCB board 200, and making the first pad 310 contact the second pad 210; Step S161: performing thermocompression welding or SMT on the first pad 310 and the second pad 210 to connect the bare chip 300 to the PCB board 200 to form an LPCAMM memory module; Step S171: Connect the LPCAMM memory module to the detachable connector, and detachably connect the detachable connector to the control mainboard.

[0036] First, a plurality of bare chips 300 are arranged on the original wafer, and a single bare chip 300 can be obtained by cutting the original wafer. Then, a first pad 310 needs to be arranged on the bare chip 300 to facilitate subsequent connection with the PCB board 200. Subsequently, the RDL technology is used to rewire the PCB board 200, so that the layout of the connection points on the PCB board 200 is completely consistent with the layout of the first pad 310, and the second pad 210 corresponding to the first pad 310 is arranged at the connection point. Next, the bare chip 300 is placed on the PCB board 200, and the first pad 310 is in contact with the second pad 210, and then the hot pressing welding method is used to heat and pressurize the first pad 310 to bond with the second pad 210, thereby realizing the connection between the bare chip 300 and the PCB board 200. In addition to the hot pressing welding method, the SMT technology can also be used to realize the connection between the first pad 310 and the second pad 210. After the bare chip 300 is connected to the PCB board 200, an LPCAMM memory module is formed. Among them, the LPCAMM memory module adopts the compression connection interface of the CAMM standard (Compression Attached Memory Module), which has strict specifications and short tracking length to achieve modular and interchangeable LPDDR5 memory. The LPCAMM memory module is connected to the detachable connector through the compression connection interface, and the detachable connector is detachably connected to the control motherboard, making the plugging and unplugging of the LPCAMM memory module more convenient.

[0037] According to the packaging method of the LPCAMM memory module of the embodiment of the present application, the bare chip 300 is connected to the PCB board 200 through the first solder pad 310 and the second solder pad 210, and the sizes of the first solder pad 310 and the second solder pad 210 are usually very small, thereby reducing the thickness of the LPCAMM memory module and meeting the ultra-thin and large capacity requirements of the AI ​​PC.

[0038] It should be noted that, although the above two packaging methods can reduce the thickness of the LPCAMM memory module, both packaging methods require rewiring of the PCB board 200. However, it is difficult to rewire the PCB board 200, and the resulting line spacing or line width is wide, which cannot meet the requirements of fine lines. For this reason, the embodiment of the present application also proposes another packaging method for the LPCAMM memory module, such as Figure 6 As shown, the method comprises the following steps: Step S120: cutting the original wafer to obtain a plurality of single bare chips; the bare chip is an LPDDR5x chip, and the bare chip has a pad; There are multiple bare chips on the original wafer, and a single bare chip can be obtained by cutting the original wafer. In order to meet the requirements of AI PC, the bare chip is an LPDDR5x chip, which has a higher storage capacity and supports a higher data transmission rate and better storage bandwidth. The bare chip is provided with a pad for electrical connection with the PCB board.

[0039] Step S220: obtaining a carrier substrate, and placing a plurality of bare chips invertedly on the carrier substrate according to a preset arrangement to form a reconstructed wafer; A reconstructed wafer is formed by placing the bare chip upside down on a carrier substrate, which facilitates subsequent rewiring of the bare chip on the reconstructed wafer.

[0040] Step S320: forming a dielectric layer on the surface of the reconstructed wafer; The dielectric layer is made of insulating materials that can be patterned by photolithography, such as polyimide, epoxy resin, etc.

[0041] Step S420: attaching a transparent filter film to the surface of the medium layer; Among them, the transparent filter film has a certain filtering effect on the light of the mixed band and can filter the light of the preset band.

[0042] Step S520: exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern. During exposure, the exposure light source is filtered through a transparent filter film. Due to the volatility of light, when short-wavelength light is irradiated onto the surface of the transparent protective film during exposure, the transparent protective film itself has a certain thickness, so the short-wavelength light source cannot penetrate the transparent protective film to irradiate the surface of the dielectric layer. The long-wavelength light source has good diffraction ability and strong penetration, and can pass through the transparent filter membrane to reach the surface of the dielectric layer for photopolymerization. At this time, the light source participating in the reaction is converted from mixed-wavelength light to single-wavelength light. Filtering the exposure light source through a transparent filter membrane can improve the exposure quality, ensure that the verticality of the rewiring pattern and the heat dissipation pattern formed is high, and make the circuit quality formed by subsequent electroplating high.

[0043] Step S620: removing the transparent filter film, electroplating the surface of the redistribution pattern to form a redistribution layer, electroplating the surface of the heat dissipation pattern to form a heat dissipation layer, and conducting the redistribution layer with the pad; After forming the redistribution pattern and the heat dissipation pattern, the transparent filter film needs to be removed, and then the redistribution layer is formed by electroplating on the surface of the redistribution pattern through the electroplating process. The redistribution layer is used to change the layout of the pads of the bare chip, and the pads of the bare chip are connected to the required position through the redistribution layer. At the same time, the heat dissipation layer is formed by electroplating on the surface of the heat dissipation pattern. The heat generated during the operation of the bare chip is dissipated through the heat dissipation layer, thereby improving the heat dissipation performance of the bare chip and ensuring the working performance of the LPCAMM memory module.

[0044] Step S720: cutting the reconstructed wafer to obtain a plurality of single bare chips after rewiring; After the redistribution layer and the heat dissipation layer are formed, the reconstructed wafer is cut to obtain a single redistribution bare chip.

[0045] Step S820: obtaining a PCB board; the PCB board is provided with a plurality of connection points and a plurality of heat dissipation points; Among them, the connection points of the PCB board are used to connect with the redistribution layer, and then connected with the solder pads of the bare chip, so as to realize the connection between the PCB board and the bare chip to form an LPCAMM module; the heat dissipation points of the PCB board are used to connect with the heat dissipation pattern to dissipate heat for the bare chip.

[0046] Step S920: connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point, and connecting the heat dissipation layer of the bare chip after rewiring to the corresponding heat dissipation point to form an LPCAMM memory module; Step S1020: Connect the LPCAMM memory module to the detachable connector, and detachably connect the detachable connector to the control mainboard.

[0047] Among them, the LPCAMM memory module adopts the compression connection interface of the CAMM standard (Compression Attached Memory Module), which has strict specifications and short tracking length to achieve modular and interchangeable LPDDR5 memory. The LPCAMM memory module is connected to the detachable connector through the compression connection interface, and the detachable connector is detachably connected to the control motherboard, making the plugging and unplugging of the LPCAMM memory module more convenient.

[0048] According to the packaging method of the LPCAMM memory module of the embodiment of the present application, after the bare chip is rewired, the bare chip is directly connected to the PCB board, thereby eliminating the need to rewire the PCB board, reducing the design difficulty of the PCB board, improving the fineness of the circuit, and reducing the thickness of the LPCAMM memory module to meet the ultra-thin and large-capacity requirements of AI PCs.

[0049] Further, in some embodiments of the present application, in the above step S920, connecting the rewiring layer of the bare chip after rewiring with the corresponding connection point includes the following three steps: (1) Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; (2) Print solder paste on the surface of the pad; (3) After the solder pads are connected to the corresponding connection points, the solder pads and the connection points are reflowed to connect the bare chip to the PCB board to form an LPCAMM memory module.

[0050] In order to facilitate the connection between the redistribution layer and the connection point of the PCB board, in this example, a pad is made at a preset position of the redistribution layer, the position of the pad corresponds to the position of the connection point one by one, and the pad is connected to the pad through the redistribution layer; then, after printing solder paste on the surface of the pad, the pad is connected to the corresponding connection point, and then the pad and the connection point are reflowed to connect the bare chip to the PCB board to form an LPCAMM memory module. In this embodiment, the layout of the pad of the bare chip is first changed through the redistribution layer, and then the connection between the redistribution layer and the PCB board is realized through the pad, so that the PCB board does not need to be rewired, the design difficulty of the PCB board is reduced, the fineness of the circuit is improved, and the thickness of the LPCAMM memory module can be reduced to meet the ultra-thin and large-capacity requirements of AIPC.

[0051] Further, in some embodiments of the present application, in the above step S920, connecting the rewiring layer of the bare chip after rewiring with the corresponding connection point includes the following two steps: (1) Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; (2) After the pad is in contact with the corresponding connection point, the pad and the corresponding connection point are heat-pressed to connect the bare chip to the PCB board to form an LPCAMM memory module.

[0052] In order to facilitate the connection between the redistribution layer and the connection point of the PCB board, in this example, a pad is made at a preset position of the redistribution layer, the position of the pad corresponds to the position of the connection point one by one, and the pad is connected to the pad through the redistribution layer; then, after the pad is in contact with the corresponding connection point, the pad and the corresponding connection point are hot-pressed to connect the bare chip to the PCB board to form an LPCAMM memory module. In this embodiment, the layout of the pad of the bare chip is first changed through the redistribution layer, and then the connection between the redistribution layer and the PCB board is realized through the pad, so that the PCB board does not need to be rewired, the design difficulty of the PCB board is reduced, the fineness of the circuit is improved, and the thickness of the LPCAMM memory module can be reduced to meet the ultra-thin and large-capacity requirements of AI PC.

[0053] Further, in some embodiments of the present application, in the above step S920, connecting the rewiring layer of the bare chip after rewiring with the corresponding connection point includes the following two steps: (1) Implanting bumps at preset positions of the redistribution layer; (2) The redistribution layer is connected to the corresponding connection points through bumps, so that the bare chip is connected to the PCB board through the redistribution layer to form an LPCAMM memory module.

[0054] In order to facilitate the connection between the redistribution layer and the connection point of the PCB board, in this example, an implanted bump is made at a preset position of the redistribution layer, the position of the bump corresponds to the position of the connection point one by one, and the bump is connected to the pad through the redistribution layer; then, the bump is connected to the corresponding connection point to connect the bare chip to the PCB board to form an LPCAMM memory module. In this embodiment, the layout of the pad of the bare chip is first changed through the redistribution layer, and then the connection between the redistribution layer and the PCB board is realized through the bump, so that the PCB board does not need to be rewired, the design difficulty of the PCB board is reduced, the fineness of the circuit is improved, and the thickness of the LPCAMM memory module can be reduced to meet the ultra-thin and large-capacity requirements of AI PC.

[0055] In some embodiments of the present application, in order to implant a bump at a preset position of a redistribution layer, the following four steps are included: (1) attaching a photosensitive dry film to the surface of the dielectric layer; (2) exposing and developing the photosensitive dry film to form a window at a preset position; (3) Electroplating to form a bump at the window; (4) Remove the photosensitive dry film.

[0056] The photosensitive dry film is exposed and developed to form a window corresponding to the bump, and then electroplating is performed in the window to form the bump, and finally the photosensitive dry film is removed.

[0057] Further, in some embodiments of the present application, the above step S1020: connecting the LPCAMM memory module to the detachable connector, and detachably connecting the detachable connector to the control mainboard, includes the following three steps: (1) Setting a CAMM standard compression connection interface for the LPCAMM memory module; (2) The LPCAMM memory module is connected to the detachable connector through a compression connection interface; (3) The detachable connector is detachably connected to the control main board.

[0058] Among them, the LPCAMM memory module adopts the compression connection interface of the CAMM standard (Compression Attached Memory Module), which has strict specifications and short tracking length to achieve modular and interchangeable LPDDR5 memory. The LPCAMM memory module is connected to the detachable connector through the compression connection interface, and the detachable connector is detachably connected to the control motherboard, making the plugging and unplugging of the LPCAMM memory module more convenient.

[0059] Further, in some embodiments of the present application, the above step S520: exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern, and filtering the exposure light source through a transparent filter film during exposure, includes the following three steps: (1) Filter out light sources with wavelengths below a preset threshold in the exposure light source through a transparent filter film; (2) exposing the dielectric layer through a filtered exposure light source; (3) Developing the exposed dielectric layer to form a redistribution pattern and a heat dissipation pattern.

[0060] Due to the volatility of light, when short-wavelength light is irradiated onto the surface of the transparent protective film during exposure, the transparent protective film itself has a certain thickness, so the short-wavelength light source cannot penetrate the transparent protective film to irradiate the surface of the dielectric layer. The long-wavelength light source has good diffraction ability and strong penetration, and can pass through the transparent filter membrane to reach the surface of the dielectric layer for photopolymerization. At this time, the light source participating in the reaction is converted from mixed-wavelength light to single-wavelength light. Filtering the exposure light source through a transparent filter membrane can improve the exposure quality, ensure that the verticality of the rewiring pattern and the heat dissipation pattern formed is high, and make the circuit quality formed by subsequent electroplating high.

[0061] On the other hand, based on the above three packaging methods of LPCAMM memory modules, the embodiments of the present application also propose three corresponding packaging structures of LPCAMM memory modules.

[0062] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A packaging method for an LPCAMM memory module, characterized in that: The method comprises the following steps: Cutting the original wafer to obtain a plurality of single bare chips; the bare chip is an LPDDR5x chip, and the bare chip has a pad; Obtaining a carrier substrate, and placing a plurality of the bare chips upside down on the carrier substrate in a preset arrangement to form a reconstructed wafer; forming a dielectric layer on the surface of the reconstructed wafer; A transparent filter membrane is attached to the surface of the medium layer; Exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern, and filtering the exposure light source through the transparent filter film during exposure; Removing the transparent filter film, electroplating to form a redistribution layer at the redistribution pattern, electroplating to form a heat dissipation layer at the heat dissipation pattern, and conducting the redistribution layer with the pad; Cutting the reconstructed wafer to obtain a plurality of single bare chips after rewiring; Obtain a PCB board; the PCB board is provided with a plurality of connection points and a plurality of heat dissipation points; Connecting the rewiring layer of the bare chip after rewiring with the corresponding connection point, and connecting the heat dissipation layer of the bare chip after rewiring with the corresponding heat dissipation point to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

2. The packaging method of the LPCAMM memory module according to claim 1, characterized in that: The step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point comprises: Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; Printing solder paste on the surface of the pad; After the pads are connected to the corresponding connection points, the pads and the connection points are reflowed to connect the bare chip to the PCB board to form the LPCAMM memory module.

3. The packaging method of the LPCAMM memory module according to claim 1, characterized in that: The step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point comprises: Making a pad at a preset position of the redistribution layer; the pad is connected to the pad through the redistribution layer; After the pad is brought into contact with the corresponding connection point, the pad and the corresponding connection point are subjected to thermal compression welding to connect the bare chip with the PCB board to form the LPCAMM memory module.

4. The packaging method of the LPCAMM memory module according to claim 1, characterized in that: The step of connecting the rewiring layer of the bare chip after rewiring to the corresponding connection point comprises: implanting bumps at predetermined positions of the redistribution layer; The redistribution layer is connected to the corresponding connection points through the bumps, so that the bare chip is connected to the PCB board through the redistribution layer to form the LPCAMM memory module.

5. The packaging method of the LPCAMM memory module according to claim 4, characterized in that: The step of implanting a bump at a preset position of the redistribution layer comprises: Attaching a photosensitive dry film on the surface of the dielectric layer; exposing and developing the photosensitive dry film to form a window at the preset position; Forming the bump at the window by electroplating; The photosensitive dry film is removed.

6. The packaging method of the LPCAMM memory module according to claim 1, characterized in that: The step of connecting the LPCAMM memory module to a detachable connector and detachably connecting the detachable connector to a control mainboard comprises: Setting a compression connection interface of the CAMM standard for the LPCAMM memory module; The LPCAMM memory module is connected to the detachable connector via the compression connection interface; The detachable connecting piece is detachably connected to the control main board.

7. The packaging method of the LPCAMM memory module according to claim 1, characterized in that: The step of exposing and developing the dielectric layer to form a redistribution pattern and a heat dissipation pattern, and filtering the exposure light source through the transparent filter film during exposure, comprises: Filtering out light sources with wavelengths lower than a preset threshold in the exposure light source through the transparent filter film; Exposing the dielectric layer through the filtered exposure light source; The exposed dielectric layer is developed to form the redistribution pattern and the heat dissipation pattern.

8. A packaging method for an LPCAMM memory module, characterized in that: The method comprises the following steps: Cutting the original wafer to obtain a plurality of single bare chips; the bare chip is an LPDDR5x chip, and the bare chip has a pad; Get the PCB board; Rewiring the circuits of the PCB board according to the positions of the soldering pads so that the connection points of the PCB board correspond to the soldering pads one by one; implanting a bump on the pad; Connecting the pads to the corresponding connection points through the bumps, so that the bare chip is connected to the PCB board to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

9. A packaging method for an LPCAMM memory module, characterized in that: The method comprises the following steps: The original wafer is cut to obtain a plurality of single bare chips; the bare chips are LPDDR5x chips; Disposing a first pad on the bare chip; Get the PCB board; Rewiring the circuit of the PCB board according to the position of the first pad, and providing a second pad corresponding to the first pad on the PCB board; Placing the bare chip on the PCB board and making the first pad contact the second pad; Performing thermal compression welding or SMT on the first pad and the second pad to connect the bare chip to the PCB board to form an LPCAMM memory module; The LPCAMM memory module is connected to a detachable connecting piece, and the detachable connecting piece is detachably connected to a control mainboard.

10. A packaging structure of an LPCAMM memory module, characterized in that: The LPCAMM memory module is manufactured by the packaging method of any one of claims 1 to 9.

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