Manufacturing method of embedded substrate and intermediate structure

Abstract

The invention discloses a manufacturing method of an embedded substrate and an intermediate structure, and relates to the technical field of semiconductor manufacturing. According to the manufacturing method of the embedded substrate, in the trepanning process of the surface of the side, away from the core plate, of the second resin layer, the second supporting plate and the core plate are still fixed together, the supporting effect of the second supporting plate is achieved in the trepanning process, the core plate cannot be warped or deformed in the trepanning process, the positioning precision of trepanning is higher, and the reliability of the embedded substrate is improved. And the core plate is always in a low-warping state, so that the interlayer alignment deviation is relatively small, and the alignment of the element position and the hole position of the circuit is easier. And the flatness of the substrate is high, the wiring exposure alignment is more accurate, and the substrate is not easy to deform in the vacuum adsorption process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, in particular to a manufacturing method of an embedded substrate and an intermediate structure. BACKGROUND

[0002] Embedding a chip in a substrate is an advanced packaging form. By embedding a bare chip in a substrate, the signal transmission distance between the chip and the surface packaging elements of the substrate and between the chips can be greatly reduced, the signal transmission loss can be reduced, and the signal transmission quality can be improved. At the same time, the packaging size is reduced, and the device usage space is compressed.

[0003] At present, the main manufacturing method of the chip embedded substrate is to embed a bare chip in a printed circuit board core plate by digging a cavity, fill the cavity with resin, and then form a substrate by multi-layer wiring on both sides of the core plate.

[0004] In the existing manufacturing method of the chip embedded substrate, the substrate is prone to severe warping during the single-sided pressing process after filling resin on one side of the substrate. During the insulation lamination and curing baking process of the other side of the substrate, the substrate is flattened again. The repeated bending of the substrate from warping to flattening can cause cracking of the rigid resin due to the high modulus of the cured embedded resin. The weak interfacial bonding force between the rigid embedded resin and the chip can also cause interfacial cracking. Resin cracking and chip interface separation can cause embedded substrate failure, and even in a humid environment, water vapor accumulation at the cracked interface can cause embedded substrate burnout and other serious reliability problems. Therefore, how to reduce the warping of the substrate during substrate processing and manufacturing is a technical problem in the processing and manufacturing of embedded substrates, and is an important problem in improving the reliability of embedded substrates.

[0005] The ultra-thin embedded substrate warps severely during manufacturing. Excessive warping not only leads to processing difficulties, but more importantly, the warped substrate has a large interlayer alignment deviation during circuit processing, making it difficult to align the chip position with the hole position of the circuit. The warping of the ultra-thin embedded substrate is mostly complex W-shaped, with a low surface flatness.

[0006] In addition, in order to achieve good alignment of the metal wiring between layers, the substrate needs to be flat before exposure of any layer of wiring. Before exposure of the ultra-thin embedded substrate, the warped substrate needs to be flattened and fixed by vacuum adsorption or adhesive tape to make the substrate flat before exposure. During the process of flattening the ultra-thin substrate, the substrate is inevitably pressed and stretched, which will cause deformation of the ultra-thin substrate and greatly affect the exposure of the wiring, and even cause local, hole and pad to fail to meet the alignment requirements. Moreover, vacuum adsorption of the ultra-thin substrate on the exposure platform will cause the ultra-thin substrate to be concave near the vacuum adsorption hole, which will also cause exposure misalignment and line width variation. Similarly, mechanical holes and laser drilled holes also face the same problem, and the deformed substrate hole cannot be properly aligned with the pad, resulting in an open circuit. SUMMARY

[0007] The present application aims to provide a manufacturing method of an embedded substrate and an intermediate structure to reduce substrate warping and delamination, improve the reliability of the embedded substrate, and improve the drilling accuracy.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0009] A manufacturing method of an embedded substrate, comprising:

[0010] Windowing a core plate to form a receiving cavity for accommodating an element, two surfaces of the core plate being a first bonding surface and a backfill resin surface, respectively;

[0011] First temporary bonding, bonding a first bonding material layer to the first bonding surface of the core plate, and the first bonding material layer being fixed with a first support plate on a side away from the core plate, the first bonding material layer comprising a foamed film, a support film and a pressure-sensitive adhesive film stacked in sequence, the foamed film of the first bonding material layer being bonded to the first support plate, and the pressure-sensitive adhesive film of the first bonding material layer being bonded to the core plate;

[0012] Element pasting, placing an element in the receiving cavity;

[0013] First compression and backfill resin and copper foil, compressing backfill resin on the backfill resin surface of the core plate to form a first resin layer, and compressing a copper foil on a side of the first resin layer away from the core plate;

[0014] Second temporary bonding, bonding a second bonding material layer to a side of the copper foil away from the core plate, and the second bonding material layer being fixed with a second support plate on a side away from the core plate, the second bonding material layer comprising a foamed film, a support film and a pressure-sensitive adhesive film stacked in sequence, the foamed film of the second bonding material layer being bonded to the copper foil, and the pressure-sensitive adhesive film of the second bonding material layer being bonded to the second support plate;

[0015] First pre-curing, pre-curing the structure formed in the previous step;

[0016] First debonding, debonding the first support plate from the first bonding material layer to remove the first support plate;

[0017] Second debonding, debonding the first bonding material layer from the core plate to remove the first bonding material layer;

[0018] Second compression embedding resin, compressing and embedding resin on the first bonding surface of the core plate to form a second resin layer;

[0019] Second pre-curing, pre-curing the structure formed in the previous step;

[0020] First hole processing, forming through holes and blind holes on the structure formed in the previous step, the through holes penetrating through the second resin layer, the core plate, the first resin layer, the copper foil and the second bonding material layer, and the blind holes penetrating through the second resin layer and at least part of the blind holes being opposite to the pads on the components;

[0021] Third debonding, debonding the second bonding material layer from the copper foil to remove the second bonding material layer and the second support plate;

[0022] Removing the copper foil, removing the copper foil on the side of the first resin layer away from the core plate;

[0023] Circuit fabrication, fabricating circuits on the upper and lower surfaces of the structure formed in the previous step;

[0024] Curing, curing the resin layers in the structure formed in the previous step to more than 90%;

[0025] Insulating layer processing, forming resin insulating layers on the upper and lower surfaces of the structure formed in the previous step, and performing third pre-curing;

[0026] Fabricating intermediate circuits and outer circuits, repeating the hole processing, circuit fabrication and insulating layer processing on the upper and lower surfaces of the structure formed in the previous step N times to form N layers of intermediate circuits, and then repeating the hole processing, circuit fabrication and curing steps to form outer circuits;

[0027] Fabricating a solder resist layer, fabricating a solder resist layer on the surface of the outer circuit;

[0028] Coating, coating the surface of the structure formed after the solder resist layer with a coating.

[0029] In an implementation, the core board comprises a double-sided copper clad board; and / or, the front and back surfaces of the core board are arranged with circuits and interconnected between the front and back surface circuits, at least one side surface of the core board is provided with a solder pad; and / or, a windowing mark and / or a patch positioning mark is made on the surface of the core board by means of photolithography and / or etching before the core board windowing step.

[0030] In an implementation, the first support plate comprises a metal plate, a glass plate and / or a resin plate; and / or, the thickness of the first support plate is greater than 200 μm; and / or, the second support plate comprises a metal plate, a glass plate and / or a resin plate; and / or, the thickness of the second support plate is greater than 200 μm.

[0031] In an implementation, in the first pre-curing step, the structure reaches a temperature higher than the debonding temperature of the first support plate and the first temporary bonding material layer, and the first bonding material layer and the first support plate are debonded to remove the first support plate in the first pre-curing step.

[0032] In an implementation, the first pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing it in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or,

[0033] The second pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing it in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or,

[0034] The third pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing it in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or,

[0035] The curing specifically comprises: heating the structure formed in the previous step to an environment of 190-210°C for 50-80 min.

[0036] In one embodiment, the second debonding step further includes the following steps: a first cleaning step of cleaning the structure formed in the previous step to remove contaminants on the surface of the structure; and / or the first hole processing step further includes the following steps: a second cleaning step of cleaning the structure formed in the previous step to remove contaminants on the surface of the structure.

[0037] In one implementation, the first resin layer and the second resin layer have the same thickness.

[0038] In one implementation, the raw materials used in the first resin and copper foil lamination step, the second resin lamination step, and the insulation layer processing step are all ABF resin sheets, and the ABF resin sheet includes an ABF layer, an OPP film attached to a first side of the ABF layer, and a PET film attached to a second side of the ABF layer; in the first resin and copper foil lamination step, the OPP film of the ABF resin sheet is removed before lamination, and the PET film is removed after lamination; or,

[0039] The raw materials used in the first pressing and embedding resin and copper foil step, the second pressing and embedding resin step, and the insulating layer processing step are all RCC.

[0040] In the above-mentioned method for manufacturing the embedded substrate, in the steps of attaching components, burying the first resin layer and the second resin layer, the first support plate and / or the second support plate support the core plate. The supporting function of the first support plate and / or the second support plate can reduce the overall warping of the core plate caused by structural asymmetry during the manufacturing process of the embedded component core plate, thereby ensuring that the core plate is always in a low-warping state during the entire manufacturing process of the embedded component core plate.

[0041] In the above-mentioned method for manufacturing the embedded substrate, the foam film of the second bonding material layer is bonded to the side of the copper foil facing away from the first resin layer. After the foam film of the second bonding material layer is debonded, the copper foil is removed to use the copper foil to protect the surface of the first resin layer, making the surface of the first resin layer smoother and free of residual foreign matter.

[0042] In the above-mentioned manufacturing method of the embedded substrate, during the process of opening a hole on the surface of the second resin layer facing away from the core board, the second support plate is still fixed to the core board. The second support plate provides support during the hole opening process, and the core board will not warp or deform during the hole opening process. The positioning accuracy of the hole opening is higher, thereby improving the reliability of the embedded substrate.

[0043] In this embedded substrate manufacturing method, the core substrate maintains a low warpage state, minimizing interlayer alignment deviations and facilitating alignment of component positions and circuit holes. Furthermore, the substrate's high flatness allows for more precise wiring exposure and alignment, and it resists deformation during vacuum adsorption.

[0044] An intermediate structure comprises:

[0045] A core plate and a component, the core plate being provided with a receiving cavity for receiving the component, the component being arranged in the receiving cavity;

[0046] A first resin layer and a second resin layer, the first resin layer and the second resin layer respectively covering two side surfaces of the core plate;

[0047] A copper foil, the first resin layer being provided with a copper foil on a side away from the core plate;

[0048] A bonding material layer and a support plate, the bonding material layer being fixedly attached to a side of the copper foil away from the core plate, the support plate being fixedly attached to a side of the bonding material layer away from the core plate;

[0049] A through hole and a blind hole, the through hole penetrating through the first resin layer, the core plate, the second resin layer, the copper foil and the bonding material layer, the blind hole penetrating through the second resin layer, at least a portion of the blind hole being opposite to a pad on the component.

[0050] In an implementation manner, the component is an active component or a passive component; and / or,

[0051] The bonding material layer comprises a foaming film, a support film and a pressure-sensitive adhesive film which are sequentially stacked, the foaming film of the bonding material layer is bonded to the copper foil, and the pressure-sensitive adhesive film of the bonding material layer is bonded to the support plate. BRIEF DESCRIPTION OF DRAWINGS

[0052] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and serve to explain the principles of the application, and do not limit the application. In the drawings:

[0053] Figure 1 A flowchart of a manufacturing method of an embedded substrate provided by an embodiment of the application;

[0054] Figure 2 A structure formed after a core plate windowing step provided by an embodiment of the application;

[0055] Figure 3 A structure formed after a first temporary bonding step provided by an embodiment of the application;

[0056] Figure 4 A structure formed after a component attaching step provided by an embodiment of the application;

[0057] Figure 5 A structure formed after a first pressing and filling resin and copper foil step provided by an embodiment of the application;

[0058] Figure 6Structure formed after the second temporary bonding step provided by the embodiment of the present application;

[0059] Figure 7 Structure formed after the second debonding step provided by the embodiment of the present application;

[0060] Figure 8 Structure formed after the second compression burying resin step provided by the embodiment of the present application;

[0061] Figure 9 Structure formed after the first hole processing step provided by the embodiment of the present application;

[0062] Figure 10 Structure formed after the third debonding step provided by the embodiment of the present application;

[0063] Figure 11 Structure formed after the circuit manufacturing step provided by the embodiment of the present application;

[0064] Figure 12 Structure formed after the manufacturing of intermediate circuit and outer circuit step provided by the embodiment of the present application;

[0065] Figure 13 Structure formed after the manufacturing of solder resist step provided by the embodiment of the present application;

[0066] Figure 14 Structure schematic diagram of the first bonding material layer or the second bonding material layer provided by the embodiment of the present application.

[0067] Reference signs:

[0068] 1-core board, 1a-housing cavity, 2-first bonding material layer, 3-first support plate, 4-element, 5-first resin layer, 6-copper foil, 7-second bonding material layer, 8-second support plate, 9-second resin layer, 10-via hole, 11-blind hole, 12-intermediate circuit, 13-outer circuit, 14-solder resist;

[0069] a-first cover film, b-pressure sensitive adhesive film, c-support film, d-foaming film, e-second cover film. DETAILED DESCRIPTION

[0070] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0071] It should be noted that when an element is referred to as being "fixed" or "set" on another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or indirectly connected to the other element.

[0072] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or an indicated number of technical features. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited. The meaning of "several" is one or more, unless otherwise explicitly specified and limited.

[0073] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0074] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0075] Please refer to Figure 1 The manufacturing method of the embedded substrate provided by the embodiments of the present application comprises the following steps:

[0076] S1, the core plate 1 is windowed, an accommodating cavity 1a for accommodating the element 4 is formed on the core plate 1, and the two surfaces of the core plate 1 are respectively a first bonding surface and a resin filling surface;

[0077] In this step, the core plate 1 can include a double-sided copper-clad plate, which can include a plate body and a copper plate covering the surfaces of the plate body on both sides. Specifically, the core plate 1 can select a double-sided copper-clad plate of E770G.

[0078] The plate body can be a BT (Bismaleimide Triazine) resin core plate 1 or a core plate 1 of FR4 material. The BT resin material has a high glass transition temperature, excellent dielectric properties, low thermal expansion rate, good mechanical characteristics and other properties, which are suitable for the manufacture of the plate body. FR4 is a code for a fire-resistant material grade, which means that the resin material must be able to self-extinguish in a burning state. Of course, the plate body can also be of other materials, which are not limited here. Of course, the core plate 1 can also only include a resin plate, and the surface of the resin plate is not covered with a copper layer.

[0079] The front and back surfaces of the core plate 1 are arranged with circuits and interconnected between the front and back surface circuits. Specifically, the front and back surfaces of the core plate 1 are arranged with lines, and the lines on the front surface and the lines on the back surface of the core plate 1 are electrically connected, so that after multiple wiring on the front and back surfaces of the core plate 1, the front surface multi-layer wiring and the back surface multi-layer wiring are electrically connected. At least one side surface of the core plate 1 is provided with a solder pad, so that the lines on the surface of the core plate 1 are electrically connected between the solder pads and other lines.

[0080] Preferably, before the core plate 1 is windowed in step S1, windowing marks and / or patch positioning marks can be made on the surface of the core plate 1 by means of photolithography and / or etching. During the windowing process on the core plate 1, the windowing marks can be followed to accurately form the position of the accommodating cavity 1a, which penetrates the thickness of the core plate 1. In addition, the patch positioning marks are provided on the core plate 1, and during the process of attaching the element 4, the front or back surface of the element 4 is positioned according to the positioning marks to accurately position the position of the element 4.

[0081] The accommodating cavity 1a formed on the core plate 1 can be a through hole 10 penetrating the thickness direction of the core plate 1. The two surfaces of the core plate 1 are respectively a first bonding surface and a resin filling surface. Specifically, the two surfaces of the core plate 1 along the thickness direction of the core plate 1 are respectively a first bonding surface and a resin filling surface, or in other words, when the core plate 1 is placed horizontally, that is, the thickness direction of the core plate 1 is along the vertical direction, the upper surface and the lower surface of the core plate 1 are respectively the resin filling surface and the first bonding surface. The structure formed after the core plate 1 is windowed is shown in Figure 2

[0082] S2: The first temporary bonding, bonding the first bonding material layer 2 with the first bonding surface of the core plate 1, and the first support plate 3 is fixed to the side of the first bonding material layer 2 away from the core plate 1, the first bonding material layer 2 includes a foaming film d, a support film c and a pressure sensitive adhesive film b which are stacked in turn, the foaming film d of the first bonding material layer 2 is bonded with the first support plate 3, and the pressure sensitive adhesive film b of the first bonding material layer 2 is bonded with the core plate 1;

[0083] ​The first bonding material layer 2 can include a foamed film d, a support film c and a pressure sensitive adhesive film b which are stacked in sequence. Specifically, the foamed film d, the support film c and the pressure sensitive adhesive film b are stacked in sequence along the thickness of the first bonding material layer 2. The first bonding material layer 2 is bonded to the first bonding surface of the core board 1, and the side of the first bonding material layer 2 away from the core board 1 is fixed with the first support plate 3.

[0084] The first bonding surface in this embodiment can be the lower surface of the core board 1. The pressure sensitive adhesive film b of the first bonding material layer 2 is bonded to the core board 1. The side of the first bonding material layer 2 away from the core board 1 is fixed with the first support plate 3, and the foamed film d of the first bonding material layer 2 is bonded to the first support plate 3, i.e. the first bonding material layer 2 is located between the first support plate 3 and the core board 1. The structure formed after the first temporary bonding step is shown in Figure 4 .

[0085] It should be noted that the first bonding material layer 2 can be bonded to the first support plate 3 first and then bonded to the core board 1. In this way, the first bonding material layer 2 can be bonded to the first support plate 3 before the component 4 is packaged for standby. The thickness of the first temporary bonding material layer is 5-20 microns.

[0086] In this embodiment, the first bonding material layer 2 can be 31950N temporary bonding glue produced by Nitto Company which can be thermally foamed at 180°C and debonded. Of course, other temporary bonding glue can also be selected according to actual conditions, which is not limited herein.

[0087] The first support plate 3 can include a metal plate, a glass plate and / or a resin plate. Of course, the first support plate 3 can also be made of other materials, which is not limited herein. The thickness of the first support plate 3 can be greater than or equal to 200 microns. Specifically, the thickness of the first support plate 3 can be 200 microns, 300 microns, 400 microns, 500 microns, etc. Further, the thickness of the first support plate 3 can be greater than or equal to 700 microns, such as 800 microns, 900 microns, etc. In this way, the strength of the first support plate 3 can be ensured to prevent the core board 1 from warping during processing.

[0088] S3: attaching a component 4, placing the component 4 in the accommodating cavity 1a;

[0089] The component 4 is arranged in the accommodating cavity 1a of the core board 1. The side of the component 4 without pads can be placed upward, and the side of the component 4 with pads can be placed downward. When the accommodating cavity 1a is a through hole 10, the side of the component 4 with pads can be in contact with the pressure sensitive adhesive of the first bonding material layer 2. The structure formed after the component 4 is attached is shown in Figure 4 .

[0090] S4: First, the resin is filled in the resin filling surface of the core board 1 to form the first resin layer 5, and then the copper foil 6 is filled on the side of the first resin layer 5 away from the core board 1 to protect the surface of the first resin layer 5.

[0091] That is, the resin is filled in the resin filling surface of the core board 1 to form the first resin layer 5. In this embodiment, the resin filling surface can be the upper surface of the core board 1. The resin is filled in the resin filling surface of the core board 1, which can be achieved by using a vacuum laminator to fill the resin in the resin filling surface of the core board 1. During the filling process, the resin fills the gaps between the surface circuits of the core board 1 and the gaps around the components 4.

[0092] Then, the copper foil 6 is filled on the side of the first resin layer 5 away from the core board 1, that is, the copper foil 6 is filled on the surface of the side of the first resin layer 5 away from the core board 1 to protect the surface of the first resin layer 5.

[0093] The structure formed after the first filling of the resin and the filling of the copper foil 6 is shown in FIG. 2. Figure 5

[0094] In the first filling of the resin step, an ABF (Ajinomoto Buildup Film) resin sheet can be used. The ABF resin sheet includes an ABF layer, an OPP (O-phenylphenol) film attached to the first side of the ABF layer, and a PET (polyethylene glycol terephthalate) film attached to the second side of the ABF layer.

[0095] In the first filling of the resin step, the OPP film of the ABF resin sheet is removed, and the first side of the ABF resin sheet is filled in the resin filling surface of the core board 1 to form the first resin layer 5, and the PET film is reserved on the side of the first resin layer 5 away from the core board 1. The side of the ABF resin sheet from which the OPP film is removed is filled in the resin filling surface of the core board 1, and then the PET film is removed, and the copper foil 6 can be directly filled on the surface of the first resin layer 5.

[0096] Specifically, a vacuum laminator can be used for low-temperature vacuum filling to fill the ABF resin sheet from which the OPP film is removed in the resin filling surface of the core board 1. In this step, the ABF resin sheet only needs to be attached and flattened in the vacuum laminator. The vacuum laminator includes a vacuum lamination section and a flattening section. The vacuum lamination section is mainly used to fill the ABF resin sheet in the resin filling surface of the core board 1. Since the surface of the inner layer circuit is not flat, the surface of the ABF resin sheet is still not flat after being filled by the vacuum lamination section. Then, the flattening section is used to flatten the ABF resin sheet to make the surface of the ABF resin sheet flat. ​

[0097] The resin can be specifically selected as ABF resin sheet of model GXT31. Of course, the resin can also be a semi-cured PP (Prepreg) sheet or a resin-coated copper (Resin Coated Copper, RCC) sheet. When the resin is selected as the resin-coated copper (RCC) sheet, since the RCC surface is provided with a copper foil 6, there is no need to press the copper foil 6 again.

[0098] The thickness of the copper foil 6 is not less than 2 μm, and specifically, the thickness of the copper foil 6 is 2 μm, 3 μm, 4 μm, 5 μm, etc., and preferably 5 μm.

[0099] S5: Second temporary bonding, bonding the second bonding material layer 7 to the side of the copper foil 6 away from the core board 1, and the second bonding material layer 7 is fixed with the second support plate 8 on the side away from the core board 1, the second bonding material layer 7 includes a foaming film d, a support film c and a pressure sensitive adhesive film b which are stacked in sequence, the foaming film d of the second bonding material layer 7 is bonded to the copper foil 6, and the pressure sensitive adhesive film b of the second bonding material layer 7 is bonded to the second support plate 8;

[0100] The second bonding material layer 7 can include a foaming film d, a support film c and a pressure sensitive adhesive film b which are stacked in sequence, and specifically, the foaming film d, the support film c and the pressure sensitive adhesive film b are stacked in sequence along the thickness of the second bonding material layer 7. The pressure sensitive adhesive film b of the second bonding material layer 7 is bonded to the second support plate 8. The foaming film d of the second bonding material layer 7 is bonded to the copper foil 6.

[0101] In this embodiment, the second bonding material layer 7 can be selected as 31950E temporary bonding glue produced by Nitto Company which can be foamed and debonded at 210°C. Of course, other temporary bonding glues can also be selected according to actual conditions, which are not limited herein.

[0102] The second support plate 8 can include a double-sided copper-clad plate, a metal plate, a glass plate and / or a resin plate. Of course, the second support plate 8 can also be made of other materials, which are not limited herein. The thickness of the second support plate 8 can be greater than or equal to 200 μm, and specifically, the thickness of the second support plate 8 can be 200 μm, 300 μm, 400 μm, 500 μm, etc. Further, the thickness of the second support plate 8 can be greater than or equal to 700 μm, such as 800 μm, 900 μm, etc., so as to ensure the strength of the second support plate 8 and prevent the core board 1 from warping during processing.

[0103] After this step, the second bonding material layer 7 is located between the second support plate 8 and the copper foil 6, and the second support plate 8 is bonded to the pressure sensitive adhesive film b of the second bonding material layer 7. The structure formed after the second temporary bonding step is shown in FIG. 2. Figure 6

[0104] ​It should be noted that the second bonding material layer 7 can be bonded with the second support plate 8 first and then bonded with the copper foil 6. In this way, the second bonding material layer 7 can be bonded with the second support plate 8 in advance before the element 4 is packaged.

[0105] S6: first pre-curing, pre-curing the structure formed in the previous step;

[0106] The first pre-curing can be low-temperature thermal curing, which cures the first resin layer 5 to a certain extent but not completely. In this step, the first resin layer 5 can be cured to more than 60%, and preferably the first resin layer 5 is cured to more than 70%.

[0107] The first pre-curing can be specifically: placing the structure formed in the previous step in a 100-130°C environment for 25-35 min, and then placing it in a 150-180°C environment for 25-35 min. Alternatively, the first pre-curing can be specifically: placing the structure formed in the previous step in a 130-160°C environment for 50-70 min. The first pre-curing is carried out in an oven. Preferably, the structure formed in the previous step is first placed in a 130°C constant temperature environment for 30 min, and then placed in a 180°C constant temperature environment for 30 min.

[0108] S7: first debonding, debonding the first support plate 3 from the first bonding material layer 2 to remove the first support plate 3;

[0109] In this step, the first bonding material layer 2 is debonded between the foamed film d and the first support plate 3, so that the first support plate 3 is separated from the first bonding material layer 2. Specifically, the structure formed in the previous step is heated to the debonding temperature of the foamed film d to make the foamed film d foam and debond. The debonding temperature of the foamed film d can be more than 160-180°C. In this step, the first bonding material layer 2 is not debonded from the core plate 1, and the second bonding material layer 7 is not debonded from the second support plate 8 and the second bonding material layer 7 is not debonded from the copper foil 6. That is, the first bonding material layer 2 is low-temperature debonded, and the second bonding material layer 7 is high-temperature debonded.

[0110] Preferably, in the first pre-curing of step S6, the structure can be heated to a temperature higher than the debonding temperature of the first support plate 3 and the first temporary bonding material layer, and the first bonding material layer 2 and the first support plate 3 are debonded in the first pre-curing step to remove the first support plate 3. Specifically, the structure can be placed in an environment above the debonding temperature of the foamed film d of the first bonding material layer 2, i.e. the structure is placed in an environment above 180°C during the first pre-curing, so that the first resin layer 5 is pre-cured, and at the same time, the foamed film d of the first bonding material layer 2 is foamed and debonded to remove the first support plate 3, so that the first pre-curing of step S6 and the first debonding of step S7 can be performed simultaneously.

[0111] S8: second debonding, debonding the first bonding material layer 2 from the core plate 1 to remove the first bonding material layer 2;

[0112] In this step, the second support plate 8 can be vacuum adsorbed on the heating plate, and the structure can be heated to 40-110°C by the heating plate to debond the first bonding material layer 2 from the core plate 1 to remove the first bonding material layer 2. Specifically, when the heating temperature reaches the debonding temperature of the pressure-sensitive adhesive film b, the pressure-sensitive adhesive film b of the first bonding material layer 2 is debonded from the core plate 1 to tear off the first bonding material layer 2 from the core plate 1. The debonding temperature of the pressure-sensitive adhesive film b can be 40-110°C, and specifically, the structure can be heated to 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or 110°C.

[0113] In this step, the second support plate 8 is vacuum adsorbed on the heating plate to fix the second support plate 8, so as to prevent the core plate 1 from warping during the tearing off of the first bonding material layer 2, and at the same time, it is more convenient to tear off the first bonding material layer 2. The structure formed after the second debonding step is shown in Figure 7

[0114] S9: second compression and filling of resin, compression and filling of resin on the first bonding surface of the core plate 1 to form a second resin layer 9;

[0115] That is, the resin is compressed and filled on the first bonding surface of the core plate 1, and the filled resin forms a second resin layer 9. The compression and filling of resin on the first bonding surface of the core plate 1 can be compression of resin on the first bonding surface of the core plate 1, and specifically, a vacuum film compression machine can be used to compress the resin on the first bonding surface of the core plate 1. During the compression and filling of resin, the resin fills the gaps between the surface circuits of the core plate 1 and the gaps around the components 4. The structure formed after the second compression and filling of resin step is shown in Figure 8

[0116] It should be noted that the thickness and material of the first resin layer 5 and the second resin layer 9 can be the same, so that the structures of the first resin layer 5 and the second resin layer 9 on the upper and lower surfaces of the core plate 1 are symmetrical, thereby reducing warping.​​

[0117] In this step, a copper foil 6 can also be laminated on the side of the second resin layer 9 facing away from the core board 1 to protect the second resin layer 9 with the copper foil 6.

[0118] In this second lamination step, an ABF (Ajinomoto Buildup Film) resin sheet can also be used. In this second lamination step, the OPP film of the ABF resin sheet is removed and the first side of the ABF resin sheet is laminated on the first bonding surface of the core board 1 to form the second resin layer 9, and the PET film remains on the side of the second resin layer 9 facing away from the core board 1. That is, in this step, the OPP film of the ABF resin sheet is torn off and the PET film remains. The side of the ABF resin sheet from which the OPP film is removed is laminated on the first bonding surface of the core board 1.

[0119] The PET film thus protects the ABF layer, and the PET film can be torn off before or after the hole processing. The lamination of the second resin layer 9 is also performed in a vacuum laminator.

[0120] In this step, the resin can specifically be an ABF resin sheet of type GXT31. Of course, the resin can also be a semi-cured PP sheet or a copper-clad resin sheet RCC, which is not limited here

[0121] S10: second pre-curing, pre-curing the structure formed in the previous step;

[0122] The second pre-curing can be low-temperature thermal curing, which cures the second resin layer 9 to a certain extent but not completely. It should be noted that during the second pre-curing process, the first resin layer 5 and the second resin layer 9 are further cured, and after the second pre-curing, the first resin layer 5 and the second resin layer 9 reach the same curing degree, but the first resin layer 5 and the second resin layer 9 are not completely cured.

[0123] The second pre-curing can be low-temperature thermal curing, which cures the second resin layer 9 to a certain extent but not completely. In this step, the second resin layer 9 and the second resin layer 9 can be cured to more than 60%, and preferably to more than 70%.

[0124] The second pre-curing can specifically be: placing the structure formed in the previous step in an environment of 100°C-130°C for 25-35 minutes, and then placing it in an environment of 150°C-180°C for 25-35 minutes. Alternatively, the second pre-curing can specifically be: placing the structure formed in the previous step in an environment of 130-160°C for 50-70 minutes. The second pre-curing is performed in an oven. Preferably, the structure formed in the previous step is first placed in a constant-temperature environment of 130°C for 30 minutes, and then placed in a constant-temperature environment of 180°C for 30 minutes.

[0125] S11: first hole processing, opening a through hole 10 and a blind hole 11 on the structure formed in the previous step, the through hole 10 penetrating the second resin layer 9, the core plate 1, the first resin layer 5, the copper foil 6 and the second bonding material layer 7, and the blind hole 11 penetrating the second resin layer 9 and at least partially opposing the pad on the component 4;

[0126] Specifically, the through hole 10 and the blind hole 11 are opened on the structure formed in the previous step, that is, the holes are opened on the side surface of the second resin layer 9 away from the core plate 1. In this step, the blind hole 11 and / or the through hole 10 can be opened on the side of the second resin layer 9 of the structure formed in the previous step away from the core plate 1. The through hole 10 penetrates the second resin layer 9, the core plate 1, the first resin layer 5, the copper foil 6 and the second bonding material layer 7. The through hole 10 facilitates the electrical connection of the circuits on both sides of the core plate 1 through the through hole 10. The blind hole 11 only penetrates the second resin layer 9 and does not penetrate the core plate 1 and the first resin layer 5. Part of the blind hole 11 opposes the pad on the component 4, facilitating the electrical connection of the pad with other circuits through the blind hole 11. The remaining blind hole 11 facilitates the electrical connection of the circuit covered by the second resin layer 9 with the outer circuit 13 through the blind hole 11.

[0127] Specifically, the blind hole 11 can be processed by laser drilling, and the through hole 10 can be processed by mechanical drilling. The structure formed after this first hole processing step is shown in Figure 9 .

[0128] It should be noted that in the S11 first hole processing step, the second support plate 8 is still fixed with the core plate 1 during the hole opening process on the side surface of the second resin layer 9 away from the core plate 1. The hole opening process is supported by the second support plate 8, and the core plate 1 will not be warped during the hole opening process. The positioning accuracy of the hole opening is higher, and the reliability of the embedded core plate 1 is improved.

[0129] S12: third debonding, debonding the second bonding material layer 7 from the copper foil 6 to remove the second bonding material layer 7 and the second support plate 8;

[0130] Specifically, the second bonding material layer 7 is debonded between the foamed film d and the copper foil 6, so that the second bonding material layer 7 is separated from the copper foil 6. Specifically, the structure formed in the previous step is heated to the debonding temperature of the foamed film d to cause the foamed film d to foam and debond. In this step S12, the structure formed in the previous step is heated to 190-250°C to debond the second bonding material layer 7 from the copper foil 6, and the second bonding material layer 7 and the second support plate 8 are removed. Preferably, the structure formed in the previous step can be heated to above 210°C. The structure formed after this third debonding step is shown in Figure 10 .

[0131] Laser debonding may be used in the first debonding, the second debonding and / or the third debonding. When laser debonding is used, the first support plate 3 and the second support plate 8 may be transparent plates, preferably glass plates.

[0132] S13: removing the copper foil 6, removing the copper foil 6 on the side of the first resin layer 5 facing away from the core board 1;

[0133] Specifically, the copper foil 6 can be removed by etching.

[0134] It should be noted that if the foam film d of the second bonding material layer 7 is directly bonded to the side of the first resin layer 5 facing away from the core board 1, a lot of dust will remain on the surface of the first resin layer 5 after the foam film d of the second bonding material layer 7 is debonded. The dust may remain on the component 4 and cannot be cleaned. In addition, the surface of the foam film d is relatively uneven and rough. If the foam film d of the second bonding material layer 7 is directly bonded to the first resin layer 5, the surface of the first resin layer 5 will also be uneven and rough, which may easily lead to a short circuit in the component 4 and delamination of the core board 1. Therefore, the foam film d of the second bonding material layer 7 is bonded to the side of the copper foil 6 facing away from the first resin layer 5. After the foam film d of the second bonding material layer 7 is debonded, the copper foil 6 is removed to use the copper foil 6 to protect the surface of the first resin layer 5, making the surface of the first resin layer 5 smoother and free of residual foreign matter. The foreign matter may include dust, residual photoresist, and temporary bonding adhesive residue.

[0135] S14: Circuit fabrication, processing circuits on the upper and lower surfaces of the structure formed in the previous step;

[0136] Specifically, the circuits are processed on the upper and lower surfaces of the structure formed in the previous step. In this embodiment, the circuits can be processed on the surfaces of the first resin layer 5 and the second resin layer 9 to form an inner layer circuit 12, and the inner layer circuit 12 can be electrically connected to the pads of the component 4 through the blind hole 11. The inner layer circuit 12 located on the upper and lower sides of the core board 1 can be electrically connected through the through hole 10. The structure formed after the circuit production step is as follows Figure 11 shown.

[0137] S15: curing, curing the resin layer in the structure formed in the previous step to more than 90%;

[0138] The high temperature curing can be used in this step. After this step, the first resin layer 5 and the second resin layer 9 can be cured to more than 90%, i.e. the curing degree of the first resin layer 5 and the second resin layer 9 is more than 90%. Specifically, the structure formed by the circuit manufacturing can be placed in an environment of 190-210°C for 50-80 minutes to cure the resin in the structure to more than 90%. For example, the structure formed by the circuit manufacturing can be placed in an environment of 190°C, 195°C, 200°C, 205°C or 210°C for 60 minutes to cure the resin in the structure to more than 90%. Preferably, the structure formed by the circuit manufacturing is placed in an environment of 190°C to cure the resin in the structure to more than 90%. This curing step can also be performed in an oven.

[0139] Specifically, the formed structure can be placed in a laminator, the structure formed in the previous step is clamped by mirror steel plates, and the resin in the structure is cured to more than 90% under a preset vacuum degree and a preset pressure. Since the laminator has mirror steel plates on the top and bottom, the core board 1 structure is flattened and cured under vacuum at a low pressure of 0.1-0.7 MPa and a temperature of 190-210°C to maintain low warping. The preset pressure is 0.1-0.7 MPa.

[0140] S16: Insulating layer processing, a resin insulating layer is arranged on the upper surface and the lower surface of the structure formed in the previous step, and third pre-curing is performed.

[0141] That is, the upper surface and the lower surface of the structure formed in the curing step are filled with embedding resin to form a resin insulating layer on the upper surface and the lower surface of the structure formed in the curing step. Specifically, the resin fills the gap between the circuits formed in the circuit manufacturing step, the resin insulating layer covers the circuits formed in the circuit manufacturing step and partially contacts the first resin layer 5 or the second resin layer 9. Third pre-curing is performed, i.e. the resin insulating layer is cured to a certain degree but not completely cured.

[0142] The resin insulating layer can also be an ABF resin sheet. In this insulating layer processing step, the OPP film of the ABF resin sheet is removed, the first side of the ABF resin sheet is pressed against the upper surface and the lower surface of the structure formed in the curing step, and third pre-curing is performed to cure the resin in the structure formed in this step to 70-80%. The side of the resin insulating layer away from the core board 1 retains a PET film to protect the resin insulating layer from being contaminated.

[0143] In this step, the resin insulating layer can specifically be an ABF resin sheet of model GXT31. Of course, the resin can also be a semi-cured PP sheet or a resin sheet RCC with copper, which is not limited here.

[0144] The third pre-curing can be specifically placing the structure formed in the previous step in an environment of 100-130°C for 25-35 minutes, and then placing it in an environment of 150-180°C for 25-35 minutes; or, the third pre-curing can be specifically placing the structure formed in the previous step in an environment of 130-160°C for 50-70 minutes. Preferably, the structure formed in the previous step is placed in a constant temperature environment of 100°C for 30 minutes, and then placed in a constant temperature environment of 180°C for 30 minutes, so that the curing degree of the resin insulation layer reaches 70-80%. The third pre-curing can also be performed in an oven.

[0145] S17: making intermediate circuits and outer circuits 13, repeating the hole processing, circuit making and insulation layer processing on the upper surface and lower surface of the structure formed in the previous step N times to form N layers of intermediate circuits, and then repeating the hole processing, circuit making and curing steps to form the outer circuits 13;

[0146] Repeating the hole processing, circuit making and insulation layer processing steps N times, N≥0, to form N layers of intermediate circuits, and then repeating the hole processing, circuit making and curing steps to form the outer circuits 13.

[0147] Wherein, when N>0, N layers of intermediate circuits can be processed in this step. When N=0, the outer circuits 13 are directly processed. That is, one layer of intermediate circuit is processed each time the hole processing, circuit making and insulation layer processing steps are repeated. Wherein, the hole processing is to process blind holes 11 on the upper surface and lower surface of the structure formed in the previous step, that is, the resin insulation layer on the upper surface and the resin insulation layer on the lower surface of the structure formed in the previous step are both processed with blind holes 11. The circuit making is to process circuits on the upper surface and lower surface of the structure formed in the previous step, that is, circuits are processed in the holes on the resin insulation layer on the upper surface and the resin insulation layer on the lower surface. The insulation layer processing is to set resin insulation layers on the upper surface and lower surface of the structure formed in the previous step, and perform the third pre-curing.

[0148] Then, the hole processing, circuit making and curing steps are repeated, that is, the holes are opened again on the upper surface and lower surface of the structure, the circuits are made to form the outer circuits 13, the outer circuits 13 are electrically connected to the internal circuits through the blind holes 11, and then the resin in the structure is cured to 90% or more, that is, the curing degree of the resin in the structure is 90% or more. The structure formed after this step is shown in Figure 12 .

[0149] S18: making a solder resist layer 14, making a solder resist layer 14 on the surface of the outer circuits 13; the structure formed after this step of making a solder resist layer 14 is shown in Figure 13 .

[0150] S19: coating, a coating is formed on the surface of the structure after the solder resist layer 14 is made. The material of the coating can be NiPdAu (nickel palladium gold), NiAu (nickel gold), Sn (tin), or OSP (Organic Solderability Preservatives).

[0151] In the manufacturing method of the embedded substrate, the first support plate 3 and / or the second support plate 8 supports the core plate 1 during the steps of attaching the component 4, embedding the first resin layer 5, and embedding the second resin layer 9. The support of the first support plate 3 and / or the second support plate 8 can reduce the overall warping of the core plate 1 caused by structural asymmetry during the manufacturing process of the embedded component 4 core plate 1, ensuring that the core plate 1 remains in a low-warping state throughout the manufacturing process of the embedded component 4 core plate 1.

[0152] In the manufacturing method of the embedded substrate, the foamed film d of the second bonding material layer 7 is bonded to the side of the copper foil 6 facing away from the first resin layer 5. After the foamed film d of the second bonding material layer 7 is debonded, the copper foil 6 is removed to protect the surface of the first resin layer 5, making the surface of the first resin layer 5 more flat and free of layer foreign matter.

[0153] In the manufacturing method of the embedded substrate, the second support plate 8 is still fixed with the core plate 1 during the process of opening a hole in the side surface of the second resin layer 9 facing away from the core plate 1. The support of the second support plate 8 during the opening process prevents the core plate 1 from warping and deforming, improving the positioning accuracy of the opening and the reliability of the embedded substrate.

[0154] In the manufacturing method of the embedded substrate, the core plate 1 is always in a low-warping state, which makes the interlayer alignment deviation small and the alignment of the component 4 position and the circuit hole position easier. The substrate has high flatness, the wiring exposure alignment is more accurate, and the substrate is less likely to deform during vacuum suction.

[0155] Preferably, after the second debonding of step S8, there is a further step of: S8' first cleaning, cleaning the structure formed in the previous step to remove contaminants on the surface of the structure. Specifically, a plasma cleaning machine can be used to clean the structure, and other cleaning methods such as ultrasonic alkaline solution cleaning can also be used, which are not limited here.

[0156] After the first hole processing step of step S11, there is a further step of: S11' second cleaning, cleaning the structure formed in the previous step to remove contaminants on the surface of the structure. Specifically, an ultrasonic water cleaning machine can be used to clean the structure, and other cleaning methods can also be used.

[0157] The embodiment of the present application also provides an intermediate structure, as shown in the drawings Figure 9 The intermediate structure comprises a core plate 1, an element 4, a first resin layer 5, a second resin layer 9, a copper foil 6, a bonding material layer and a support plate. The core plate 1 is provided with a receiving cavity 1a for accommodating the element 4, and the two side surfaces of the core plate 1 are respectively covered by the first resin layer 5 and the second resin layer 9. The copper foil 6 covers one side of the first resin layer 5 away from the core plate 1. The bonding material layer (i.e. the second bonding material layer 7 in the above embodiment) is fixedly attached to one side of the copper foil 6 away from the core plate 1, and the support plate (i.e. the second support plate 8 in the above embodiment) is fixedly attached to one side of the bonding material layer away from the core plate 1. The through hole 10 penetrates the first resin layer 5, the core plate 1, the second resin layer 9, the copper foil 6 and the bonding material layer, and the blind hole 11 penetrates the second resin layer 9 and at least part of the blind hole 11 is opposite to the solder pad on the element 4. The through hole 10 facilitates the electrical connection of the circuits on the two sides of the core plate 1 through the through hole 10. The blind hole 11 only penetrates the second resin layer 9 and does not penetrate the core plate 1 and the first resin layer 5, and part of the blind hole 11 is opposite to the solder pad on the element 4, so as to facilitate the electrical connection of the solder pad with other circuits through the blind hole 11, and the rest of the blind hole 11 facilitates the electrical connection of the circuits covered by the second resin layer 9 with the outer circuit 13 through the blind hole 11.

[0158] In the above intermediate structure, if the foamed film d of the bonding material layer is directly bonded to one side of the first resin layer 5 away from the core plate 1, after the foamed film d of the second bonding material layer 7 is debonded, more dust will be left on the surface of the first resin layer 5, which may not be cleaned completely on the element 4. In addition, the surface of the foamed film d is rough and uneven, and if the foamed film d of the second bonding material layer 7 is directly bonded to the first resin layer 5, the surface of the first resin layer 5 will also be rough and uneven, which will easily cause short circuit of the element 4 and delamination of the core plate 1. Therefore, the foamed film d of the bonding material layer is bonded to one side of the copper foil 6 away from the first resin layer 5, so that after the foamed film d of the bonding material layer is debonded, the copper foil 6 is removed to protect the surface of the first resin layer 5, so that the surface of the first resin layer 5 is more flat and has no foreign matter left.

[0159] In addition, during the process of opening the through hole 10 and the blind hole 11, the support plate is still fixedly attached to the core plate 1, and the support plate provides support during the opening process, so that the core plate 1 will not be warped and deformed during the opening process, the positioning accuracy of the opening is higher, and the reliability of the embedded substrate is improved.

[0160] The bonding material layer comprises the foamed film d, the support film c and the pressure-sensitive adhesive film b which are sequentially stacked, the foamed film d of the bonding material layer is bonded to the copper foil 6, and the pressure-sensitive adhesive film b of the bonding material layer is bonded to the support plate.

[0161] As shown in the drawings Figure 14As shown, the first bonding material layer 2 and / or the second bonding material layer 7 can further comprise a first cover film a and a second cover film e, wherein the first cover film a is located on the side of the pressure sensitive adhesive film b facing away from the support film c, and the second cover film e is located on the side of the foaming film d facing away from the support film c. The first cover film a and / or the second cover film e can be removed before bonding.

[0162] The element 4 can be an active element or a passive element. Preferably, the element is a chip. The side of the element having the pads is in contact with the pressure sensitive adhesive film of the first bonding material layer 2, which is more convenient for alignment.

[0163] In the description of the above-mentioned embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0164] The above describes only the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for manufacturing a buried substrate, characterized by, The method comprises the following steps: core plate windowing, a core plate is provided with a receiving cavity for receiving an element, two surfaces of the core plate are respectively a first bonding surface and a resin filling surface; first temporary bonding, a first bonding material layer is bonded to the first bonding surface of the core plate, and a first support plate is fixed to a side of the first bonding material layer away from the core plate, the first bonding material layer comprises a foaming film, a support film and a pressure sensitive adhesive film which are stacked in sequence, the foaming film of the first bonding material layer is bonded to the first support plate, and the pressure sensitive adhesive film of the first bonding material layer is bonded to the core plate; element pasting, the element is placed in the receiving cavity; first compression resin filling and copper foil pressing, resin is compressed on the resin filling surface of the core plate to form a first resin layer, and a copper foil is compressed on a side of the first resin layer away from the core plate; second temporary bonding, a second bonding material layer is bonded to a side of the copper foil away from the core plate, and a second support plate is fixed to a side of the second bonding material layer away from the core plate, the second bonding material layer comprises a foaming film, a support film and a pressure sensitive adhesive film which are stacked in sequence, the foaming film of the second bonding material layer is bonded to the copper foil, and the pressure sensitive adhesive film of the second bonding material layer is bonded to the second support plate; first pre-curing, the structure formed in the previous step is pre-cured; first debonding, the first support plate is debonded from the first bonding material layer to remove the first support plate; second debonding, the first bonding material layer is debonded from the core plate to remove the first bonding material layer; second compression resin filling, resin is compressed on the first bonding surface of the core plate to form a second resin layer; second pre-curing, the structure formed in the previous step is pre-cured; first hole processing, a through hole and a blind hole are formed on the structure formed in the previous step, the through hole penetrates the second resin layer, the core plate, the first resin layer, the copper foil and the second bonding material layer, and the blind hole penetrates the second resin layer and at least part of the blind hole is opposite to a pad on the element; third debonding, the second bonding material layer is debonded from the copper foil to remove the second bonding material layer and the second support plate; copper foil removal, the copper foil on a side of the first resin layer away from the core plate is removed; circuit making, circuits are made on upper and lower surfaces of the structure formed in the previous step; curing, the resin layers in the structure formed in the previous step are cured to more than 90%; insulating layer processing, resin insulating layers are arranged on the upper and lower surfaces of the structure formed in the previous step, and third pre-curing is performed; intermediate circuit and outer circuit making, the upper and lower surfaces of the structure formed in the previous step are processed by hole processing, circuit making and insulating layer processing for N times to form N layers of intermediate circuits, and then the structure is processed by hole processing, circuit making and curing to form an outer circuit; solder mask making, a solder mask is made on a surface of the outer circuit; coating, a coating is applied to a surface of the structure formed after the solder mask is made.

2. The manufacturing method of a buried substrate according to claim 1, wherein The core board comprises a double-sided copper-clad board; and / or, the core board is arranged with circuits on both sides and the circuits on the opposite sides are interconnected, at least one side surface of the core board is provided with a solder pad; and / or, a window marking and / or a patch positioning marking are made on the surface of the core board by means of photoetching and / or etching before the windowing step of the core board.

3. The manufacturing method of a buried substrate according to claim 1, wherein The first support plate comprises a metal plate, a glass plate and / or a resin plate; and / or, the thickness of the first support plate is greater than 200 μm; and / or, the second support plate comprises a metal plate, a glass plate and / or a resin plate; and / or, the thickness of the second support plate is greater than 200 μm.

4. The manufacturing method of a buried substrate according to claim 1, wherein In the first pre-curing step, the structure reaches a temperature higher than the debonding temperature of the first support plate and the first temporary bonding material layer, and the first bonding material layer and the first support plate are debonded to remove the first support plate in the first pre-curing step.

5. The manufacturing method of a buried substrate according to claim 1, wherein The first pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing the structure in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or, The second pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing the structure in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or, The third pre-curing specifically comprises: placing the structure formed in the previous step in an environment of 100-130°C for 25-35 min, and then placing the structure in an environment of 150-180°C for 25-35 min; or, placing the structure formed in the previous step in an environment of 130-160°C for 50-70 min; and / or, The curing specifically comprises: heating the structure formed in the previous step to an environment of 190-210°C for 50-80 min.

6. The method of manufacturing a buried substrate according to claim 1, wherein The second debonding further comprises a first cleaning step of cleaning the structure formed in the previous step to remove contaminants on the surface of the structure. The second debonding further comprises a first cleaning step of cleaning the structure formed in the previous step to remove contaminants on the surface of the structure.

7. The manufacturing method of a buried substrate according to one of claims 1, wherein The first resin layer and the second resin layer have the same thickness.

8. The manufacturing method of a buried substrate according to one of claims 1, wherein In the first pressing and filling resin and copper foil step, the second pressing and filling resin step and the insulation layer processing step, the raw material used is an ABF resin sheet, the ABF resin sheet comprises an ABF layer, an OPP film attached to the first side of the ABF layer and a PET film attached to the second side of the ABF layer; in the first pressing and filling resin and copper foil step, the OPP film of the ABF resin sheet is removed before the ABF resin sheet is pressed, and the PET film is removed after the ABF resin sheet is pressed; or, The first pressing and filling resin and copper foil step, the second pressing and filling resin step, and the insulating layer processing step all use RCC as the raw material.

9. An intermediate structure, characterized by The application relates to a core board and a component, and belongs to the technical field of printed circuit boards. The core board is provided with a component accommodating cavity for accommodating the component, and the component is arranged in the accommodating cavity. A first resin layer and a second resin layer cover two side surfaces of the core board respectively. A copper foil is arranged on the side of the first resin layer away from the core board. A bonding material layer is fixedly attached to the side of the copper foil away from the core board, and a support plate is fixedly attached to the side of the bonding material layer away from the core board. A through hole penetrates the first resin layer, the core board, the second resin layer, the copper foil and the bonding material layer, and a blind hole penetrates the second resin layer, and at least part of the blind hole is opposite to a bonding pad on the component.

10. The intermediate structure of claim 9, wherein, The component is an active component or a passive component; and / or The bonding material layer comprises a foaming film, a support film and a pressure-sensitive adhesive film which are stacked in sequence, the foaming film of the bonding material layer is bonded to the copper foil, and the pressure-sensitive adhesive film of the bonding material layer is bonded to the support plate.

Images