Component embedding method and PCB structure having component embedded therein

Abstract

The present application provides a component embedding method and a PCB structure having a component embedded therein. The method comprises the following steps: stacking at least two core boards, and stackingly arranging a first prepreg between every two adjacent core boards to obtain a laminate, the laminate being provided with at least one through slot penetrating in the thickness direction; sequentially arranging a second prepreg and a first copper foil at one end of the through slot; placing a component into the through slot, and sequentially arranging a third prepreg and a second copper foil at the other end of the through slot to obtain a pre-laminated member; performing hot lamination on the pre-laminated member to obtain a laminated member; and performing a windowing treatment on the laminated member to expose an electrode of the component, and electroplating a metal lead at the exposed electrode to obtain a PCB structure having the component embedded therein. According to the component embedding method, stable embedding of the component can be achieved without being limited by the size of the component, and the component can be well protected from being damaged, thereby improving product reliability. Moreover, the process is simple, and large-scale industrial production can be implemented.

Description

Component embedding method and PCB structure of embedded components

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on November 22, 2023, with application number 202311570511.2 and application name “Method for embedding components and PCB structure with embedded components”, and application number 202323165260.8 and application name “PCB structure, pre-pressed parts and equipment with embedded components”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the technical field of PCB (Printed Circuit Board) preparation, and in particular to a component embedding method and a PCB structure with embedded components. Background Art

[0003] Currently, most embedded component PCBs are manufactured by placing the components into pre-set slots in the core board, filling them with resin, and curing them to achieve a bond between the core board and the components. This method results in a poorly uniform bond and makes it difficult to avoid damage to the components during further operation, impacting product reliability. Summary of the Invention

[0004] In view of this, the present application provides a component embedding method that can achieve stable embedding of components, better protect components from damage, and improve product reliability; and the process is simple, and can achieve large-scale industrial production.

[0005] A first aspect of the present application provides a method for embedding components, comprising the following steps:

[0006] stacking at least two core plates, and stacking at least one first prepreg between every two adjacent core plates of the at least two core plates to obtain a stacked body, wherein the stacked body has at least one through groove penetrating the stacked body in a thickness direction;

[0007] A second prepreg and a first copper foil stacked with the laminate are sequentially arranged at one end of the through groove;

[0008] placing a component into the through-groove, the component being in contact with and stacked on the second prepreg, with a first gap being provided between the groove wall of the through-groove and the component;

[0009] A third prepreg and a second copper foil are sequentially arranged at the other end of the through groove to obtain a pre-pressed component, wherein the third prepreg is in contact with and laminated on the laminate;

[0010] performing heat pressing on the pre-pressed component, wherein during the heat pressing process, the insulating resin in the first prepreg, the second prepreg, and the third prepreg becomes fluid and flows into the first gap and solidifies to fill the first gap, thereby obtaining a press-fit component;

[0011] The pressed part is subjected to a window opening process to expose the electrodes of the components, and metal leads are electroplated at the exposed electrodes to obtain a PCB structure with embedded components.

[0012] The above-mentioned component embedding method provided by the embodiment of the present application is not limited by the size of the device, can realize the stable embedding of the components, can better protect the components from being damaged, and improve the reliability of the product; and the process is simple, and can realize large-scale industrial production. Specifically, the embedding method is to stack a first semi-cured sheet between each adjacent two core plates, and respectively set a second semi-cured sheet and a third semi-cured sheet at the upper and lower ends of the stacked body composed of the core plate and the first semi-cured sheet, so that after hot pressing, the components can be accurately and firmly fixed in the preset position in the through groove of the stacked body, and can better protect the components from being damaged by pressure during the entire embedding operation process, thereby improving the reliability of the product; the component embedding method can be applied to the embedding of components of various thicknesses, and in particular, it can better solve the problem of the prior art that the first gap cannot be filled with glue due to the large thickness of the component, making it difficult to embed large-thickness components; the component embedding method adopts the hot pressing technology commonly used in the field of PCB preparation, and the process is relatively simple and controllable, and easy to achieve large-scale production.

[0013] In an embodiment of the present application, the thickness of the stack before hot pressing is greater than the maximum thickness of the component, and in the pre-pressed part, there is a second gap between the third semi-cured sheet and the component; the width of the second gap is greater than or equal to 0.01 mm and less than or equal to 0.15 mm; and the thickness of the stack after hot pressing is greater than or equal to the maximum thickness of the component.

[0014] In an embodiment of the present application, the preparation of the laminate specifically includes: first preparing corresponding through holes on the at least two core boards and the at least one first semi-cured sheet, and then stacking the at least two core boards and the at least one first semi-cured sheet to obtain the laminate.

[0015] In the embodiment of the present application, the width of the first gap is less than or equal to 0.15 mm.

[0016] In the embodiment of the present application, the difference between the thermal expansion coefficient of the laminate after thermal pressing and the thermal expansion coefficient of the component is within 3 ppm.

[0017] In the embodiment of the present application, the core board includes a non-copper-clad board or a copper-clad board; the copper-clad board includes a substrate and a copper layer arranged on one side or both sides of the substrate.

[0018] In the implementation manner of the present application, the components include active components or passive components.

[0019] In the embodiment of the present application, the active components include chips, transistors, thyristor rectifiers, diodes, valves, vacuum tubes, displays, integrated circuits, image tubes, field-effect transistors, bipolar transistors, and integrated circuits; the passive components include resistors, capacitors, inductors, ceramic oscillators, crystal oscillators, or transformers.

[0020] A second aspect of the present application provides a pre-laminated part, the pre-laminated part comprising a first copper foil, a second prepreg, a laminate, a third prepreg, and a second copper foil stacked in sequence, and components;

[0021] The stack includes at least two core plates stacked together, and at least one first semi-cured sheet arranged between each adjacent two core plates of the at least two core plates. The stack has at least one through groove running through the stack along the thickness direction, and the second semi-cured sheet and the third semi-cured sheet are used to seal both ends of the through groove; the component is arranged in the through groove, and the component is stacked in contact with the second semi-cured sheet, and there is a first gap between the groove wall of the through groove and the component.

[0022] In the embodiment of the present application, a second gap is provided between the third prepreg and the component; a width of the second gap is greater than or equal to 0.01 mm and less than or equal to 0.15 mm.

[0023] According to a third aspect of the present application, there is provided a PCB structure with embedded components, comprising a first copper foil, a second insulating dielectric layer, a laminated structure, a third insulating dielectric layer, and a second copper foil stacked in sequence, as well as components and metal leads.

[0024] The stacked structure includes at least two core plates stacked together, and at least one first insulating medium layer arranged between each adjacent two core plates of the at least two core plates. The stacked structure has at least one through-groove running through the stacked structure along the thickness direction; the component is arranged in the through-groove, and the component is in contact with and stacked with the second insulating medium layer and the third insulating medium layer. There is a first gap between the groove wall of the through-groove and the component, and the fourth insulating medium layer fills the first gap; the metal lead is in contact with and connected to the electrode of the component, and is partially exposed for external electrical connection.

[0025] In the embodiment of the present application, the thickness of the stacked structure is greater than or equal to the maximum thickness of the component.

[0026] In an embodiment of the present application, the surface of the second insulating dielectric layer close to the component is a plane; the surface of the third insulating dielectric layer close to the component is a plane, or has a convex layer structure protruding toward the component at a position corresponding to the component.

[0027] In the embodiment of the present application, the width of the first gap is less than or equal to 0.15 mm.

[0028] In the embodiment of the present application, the difference between the thermal expansion coefficient of the stacked structure and the thermal expansion coefficient of the component is within 3 ppm.

[0029] In an embodiment of the present application, the core board includes a non-copper clad board or a copper clad board; the copper clad board includes a substrate and a copper layer arranged on one side or both sides of the substrate; the components include active components or passive components; the first insulating dielectric layer, the second insulating dielectric layer and the third insulating dielectric layer include epoxy resin and reinforcing material, and the fourth insulating dielectric layer includes epoxy resin but does not include reinforcing material.

[0030] An embodiment of the present application further provides an electronic device, comprising a PCB structure with embedded components as described in the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of a process for embedding components according to an embodiment of the present application;

[0032] FIG2 is a schematic diagram of the preparation process of the laminate provided in an embodiment of the present application;

[0033] FIG3 is a schematic diagram of the cross-sectional structure of a laminate provided by another embodiment of the present application;

[0034] FIG4 is a schematic diagram of the cross-sectional structure of a laminate provided by another embodiment of the present application;

[0035] FIG5 is a schematic cross-sectional view of a pre-pressed component 100 provided in one embodiment of the present application;

[0036] FIG6 is a schematic cross-sectional view of a pre-pressed component 100 provided in another embodiment of the present application;

[0037] FIG7 is a schematic cross-sectional view of a pre-pressed component 100 provided in another embodiment of the present application;

[0038] FIG8 is a schematic cross-sectional view of a PCB structure 200 with embedded components provided in one embodiment of the present application;

[0039] FIG9 is a schematic cross-sectional view of a PCB structure 200 with embedded components according to another embodiment of the present application;

[0040] FIG10 is a schematic cross-sectional view of a PCB structure 200 with embedded components according to another embodiment of the present application;

[0041] FIG11 is a schematic structural diagram of a device 300 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The present application is further described in detail below in conjunction with preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0043] The present application provides a component embedding method that can achieve stable embedding of components, better protect components from damage, and improve product reliability; the process is simple and can achieve large-scale industrial production.

[0044] Referring to FIG. 1 , FIG. 1 is a schematic flow chart of a component embedding method provided in an embodiment of the present application. FIG. 1 is a cross-sectional view. The component embedding method provided in the present application includes the following steps:

[0045] S101, stacking at least two core panels 10, and stacking at least one first prepreg 20 between each two adjacent core panels 10 of the at least two core panels 10 to obtain a stack 11, wherein the stack 11 has at least one through groove 11a penetrating the stack 11 in a thickness direction;

[0046] S102, sequentially placing the second prepreg 30 and the first copper foil 40 stacked with the laminate 11 at one end of the through groove 11a;

[0047] S103, placing the component 50 into the through-slot 11a, the component 50 and the second prepreg 30 are in contact and stacked, with a first gap 11b between the groove wall of the through-slot 11a and the component 50;

[0048] S104, sequentially placing a third prepreg 60 and a second copper foil 70 at the other end of the through groove 11a to obtain a pre-pressed component 100, with the third prepreg 60 contacting and laminating the laminate 11;

[0049] S105, subjecting the pre-pressed component 100 to thermal pressing. During the thermal pressing process, the insulating resin in the first prepreg 20, the second prepreg 30, and the third prepreg 60 becomes fluid and flows into the first gap 11b to fill the first gap 11b. After complete curing, a press component is obtained.

[0050] S106 , performing a windowing process on the pressed part to expose the electrodes 51 of the components 50 , and electroplating metal leads 52 on the exposed electrodes 51 to obtain a PCB structure 200 with embedded components.

[0051] The above-mentioned component embedding method provided by the embodiment of the present application is not limited by the size of the device, can realize the stable embedding of the components, can better protect the components from being damaged, and improve the reliability of the product; and the process is simple, and can realize large-scale industrial production. Specifically, the embedding method is to stack a first semi-cured sheet between each adjacent two core plates, and respectively set a second semi-cured sheet and a third semi-cured sheet at the upper and lower ends of the stacked body composed of the core plate and the first semi-cured sheet, so that after hot pressing, the components can be accurately and firmly fixed in the preset position in the through groove of the stacked body, and can better protect the components from being damaged by pressure during the entire embedding operation process, thereby improving the reliability of the product; the component embedding method can be applied to the embedding of components of various thicknesses, and in particular, it can better solve the problem of the prior art that the first gap cannot be filled with glue due to the large thickness of the component, making it difficult to embed large-thickness components; the component embedding method adopts the hot pressing technology commonly used in the field of PCB preparation, and the process is relatively simple and controllable, and easy to achieve large-scale production.

[0052] In step S101, the core board 10 can be a non-copper clad board or a copper clad board. Among them, the non-copper clad board can be a reinforcing material (such as glass fiber cloth) impregnated with epoxy resin and formed by hot pressing. The copper clad board can include a substrate and a copper layer arranged on one side or both sides of the substrate, and the substrate is a non-copper clad board. The copper clad board can be a reinforcing material (such as glass fiber cloth) impregnated with epoxy resin, and then covered with copper foil on one or both sides and formed by hot pressing. The core board 10 can be a non-copper clad board, a single-sided copper clad board, or a double-sided copper clad board selected according to actual conductive needs. The thickness of the core board 10 can be selected according to the thickness of the component 50 to be embedded. The difference between the thermal expansion coefficient of the core board 10 and the thermal expansion coefficient of the component 50 is within 3ppm. The small difference in thermal expansion coefficient between the core board 10 and the component 50 is conducive to improving the reliability of the PCB structure 200 with embedded components in high temperature scenarios.

[0053] The first semi-cured sheet 20 can be a semi-solid sheet made of a reinforcing material (such as glass fiber cloth) impregnated with epoxy resin. The thickness of the first semi-cured sheet 20 can be selected according to the thickness of the component 50 to be embedded. The thickness of the first semi-cured sheet 20 must ensure that the glue flowing out of the hot pressing can eventually fill the first gap 11b between the groove wall of the through groove 11a and the component 50. The thermal expansion coefficient of the first semi-cured sheet 20 after hot pressing and curing is within 3ppm of the thermal expansion coefficient of the component 50. The difference in thermal expansion coefficients between the two is small, which is conducive to improving the reliability of the PCB structure 200 with embedded components in high temperature scenarios. Other fillers can also be added to the first semi-cured sheet 20 as needed to improve performance, such as adding materials with low thermal expansion coefficients to reduce the thermal expansion coefficient, adding pigments to change the color, adding heat dissipation materials such as ceramics to improve heat dissipation performance, etc.

[0054] In the embodiment of the present application, the thickness of the laminate 11 before hot pressing is greater than the maximum thickness of the component 50 to be embedded, and the thickness of the laminate 11 after hot pressing is greater than or equal to the maximum thickness of the component 50 to be embedded. This ensures that the pressure during hot pressing is not directly applied to the component 50, causing component 50 abnormalities. Moreover, during hot pressing, the second prepreg 30 and the third prepreg 60 act as a fluid buffer to the pressing pressure, thereby better protecting the component 50 and improving product reliability. The maximum thickness of the component 50 refers to the upper limit of the tolerance for the thickness of the component 50.

[0055] It is understood that the difference between the thickness of the stack 11 before hot pressing and the maximum thickness of the component 50 to be embedded is designed to effectively protect the component from pressure damage and to ensure that the insulating dielectric layer formed by the third prepreg after pressing forms a close contact with the component. In some embodiments, the difference between the thickness of the stack 11 before hot pressing and the maximum thickness of the component 50 to be embedded can be greater than or equal to 0.01mm and less than or equal to 0.15mm. Controlling the difference within this range can effectively protect the component from pressure damage and facilitate the insulating dielectric layer formed by the third prepreg after pressing and the component to form a close contact, thereby better fixing the component. In some embodiments, the difference between the thickness of the stack 11 before hot pressing and the maximum thickness of the component 50 to be embedded is 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.08mm, 0.1mm, 0.12mm, or 0.15mm.

[0056] It can be understood that the thickness of the laminate 11 after thermal compression bonding is smaller than that before thermal compression bonding, which is mainly due to the change of the first prepreg 20 .

[0057] In the embodiment of the present application, the difference in thermal expansion coefficient between the laminate 11 after thermal pressing and the component 50 is within 3 ppm. This small difference in thermal expansion coefficient between the laminate 11 after thermal pressing and the component 50 is beneficial for improving the reliability of the PCB structure 200 with embedded components in high-temperature environments and aging resistance.

[0058] Referring to Figure 2, in the embodiment of the present application, the preparation process of the stack 11 may specifically include: first preparing corresponding through holes on at least two core boards 10 and at least one first semi-cured sheet 20; then stacking the at least two core boards 10 and at least one first semi-cured sheet 20 with the prepared through holes according to the corresponding positions of the through holes to obtain the stack 11.

[0059] The through holes can be prepared by mechanical or laser grooving. It is understood that, after lamination, the corresponding through holes provided on the core plate 10 and the first prepreg 20 form through-grooves 11a extending through the laminate 11. The shape of the through-grooves 11a is substantially consistent with the shape of the component 50 to be embedded. The dimensions of the through-grooves 11a are slightly larger than the dimensions of the component 50 to be embedded, so that a first gap 11b of a certain width is formed between the groove wall of the through-grooves 11a and the component 50.

[0060] In the present application, the stack 11 has at least one through-groove 11a that runs through the stack 11 in the thickness direction. Specifically, the number of through-grooves 11a can be set according to the number of components that actually need to be embedded, and can be one, two, or more. Generally, one through-groove 11a corresponds to one embedded component 50. In some embodiments, as shown in FIG2 , the stack 11 has one through-groove 11a that runs through the stack 11 in the thickness direction. In some embodiments, as shown in FIG3 , the stack 11 has two through-grooves 11a that run through the stack 11 in the thickness direction. When the stack 11 has a plurality of through-grooves 11a for embedding components 50, the lateral dimensions of the plurality of through-grooves 11a can be the same or different, and can be set specifically according to the situation of the components 50.

[0061] In the present application, one first prepreg 20 may be stacked between every two adjacent core plates 10 , or a plurality (two or more) of first prepregs 20 may be stacked.

[0062] In the embodiment of the present application, two or more core plates 10 may be stacked, and at least one first prepreg 20 may be stacked between each two adjacent core plates 10 to form a stack 11. The specific number of core plates 10 forming the stack 11 may be set as needed, for example, it may be 2-10. As shown in Figure 1, in some embodiments of the present application, two core plates 10 are stacked, and a first prepreg 20 is stacked between the two core plates 10 to form a stack 11. As shown in Figure 4, Figure 4 is a schematic diagram of the cross-sectional structure of the stack 11 provided in another embodiment of the present application. In other embodiments of the present application, five core plates 10 are stacked, and at least one first prepreg 20 is stacked between each two adjacent core plates 10 to form a stack 11. In some embodiments of the present application, the specific number of core plates 10 forming the stack 11 may be set according to the thickness of the components 50 to be embedded as needed. The number and thickness of the first prepreg 20 forming the stack 11 are designed to be able to fill the first gap 11b after hot pressing.

[0063] In step S102, a second prepreg 30 and a first copper foil 40 are sequentially placed at one end of the through-slot 11a, stacked with the laminate 11. The second prepreg 30 and the first copper foil 40 seal one end of the through-slot 11a. On the one hand, the second prepreg 30 and the first copper foil 40 can support and encapsulate the component 50 when it is subsequently placed into the through-slot 11a and in the final structure. On the other hand, the second prepreg 30 is in a semi-cured state and becomes fluid during the application of pressure during thermal compression, thus effectively protecting the component 50. Furthermore, the insulating resin in the second prepreg 30 can become fluid during the thermal compression process and partially flow into the first gap 11b to fill it, thereby better securing and protecting the component 50 and improving product reliability. The second prepreg 30 can be a semi-solid sheet made of a reinforcing material (such as glass fiber cloth) impregnated with epoxy resin. The thickness of the second prepreg 30 can be designed based on actual product requirements, such as the thickness of the final PCB structure. In some embodiments, the coefficient of thermal expansion of the second prepreg 30 after thermal compression curing is within 3 ppm of that of the component 50. This small difference in coefficient of thermal expansion helps improve the reliability of the embedded component PCB structure 200 in high-temperature environments. Other fillers may be added to the second prepreg 30 as needed to enhance performance, such as low-coefficient-of-thermal-expansion materials to reduce the coefficient of thermal expansion, pigments to change the color, and heat-dissipating materials such as ceramics to enhance heat dissipation.

[0064] In step S103, the components 50 can be various electronic components, including active components (i.e., active devices) or passive components (i.e., passive devices). Active components can be components that extract energy from an external power source, generate energy gain in the circuit, and amplify the signal. For example, they can include chips (e.g., memory chips, power chips, logic chips, etc.), transistors, thyristor rectifiers, diodes, valves, vacuum tubes, displays, integrated circuits, image tubes, field-effect transistors (MOSFETs), bipolar junction transistors (BJTs), integrated circuits (including operational amplifiers, logic gates, etc.). Passive components refer to components that cannot generate energy gain in the circuit and are mainly used to adjust, filter, store, and transmit current, voltage, and frequency. For example, they can include resistors, capacitors, inductors, ceramic oscillators, crystal oscillators, transformers, etc.

[0065] In some embodiments, the components 50 are cleaned and dried with anhydrous alcohol or plasma before being placed in the through-slots 11a to avoid the effects of impurities on the components 50. The components 50 are laminated in contact with the second prepreg 30, which supports the components 50. When the laminate 11 has multiple through-slots 11a, each through-slot 11a can accommodate a corresponding component 50.

[0066] In the present application, there is a first gap 11b between the groove wall of the through groove 11a and the component 50. After the first gap 11b is subsequently filled with the insulating medium formed by the first semi-cured sheet 20, the second semi-cured sheet 30 and the third semi-cured sheet 60, a low-stress and firm bond can be achieved between the laminate 11 and the component 50, thereby improving product reliability. The width of the first gap 11b can be less than or equal to 0.15mm. In some embodiments, the width of the first gap 11b is 0.03mm-0.15mm. In some embodiments, the width of the first gap 11b can be, for example, 0.03mm, 0.04mm, 0.05mm, 0.08mm, 0.1mm, 0.12mm, or 0.15mm. The through groove 11a serves as a space for accommodating the component 50 and can play a positioning role for the component 50. Controlling the first gap 11b between the groove wall of the through groove 11a and the component 50 to an appropriate width size is conducive to ensuring the positioning accuracy of the component 50, improving the embedding accuracy of the product, and achieving a firm connection between the component 50 and the stack 11, thereby improving product reliability; at the same time, it is conducive to the realization of mass production.

[0067] In step S104, the third prepreg 60 and the second copper foil 70 stacked with the laminate 11 are sequentially arranged at the other end of the through groove 11a. The third prepreg 60 and the second copper foil 70 seal the other end of the through groove 11a to obtain a pre-pressed component.

[0068] Accordingly, referring to FIG5, FIG6 and FIG7, the embodiment of the present application provides a pre-pressed component 100, comprising a first copper foil 40, a second prepreg 30, a laminate 11, a third prepreg 60 and a second copper foil 70 stacked in sequence, and a component 50;

[0069] The laminate 11 includes at least two stacked core sheets 10, and at least one first prepreg 20 disposed between each adjacent two of the at least two core sheets 10. The laminate 11 has at least one through-slot 11a extending through the laminate 11 in the thickness direction. A second prepreg 30 and a third prepreg 60 are used to seal both ends of the through-slot 11a. The component 50 is disposed within the through-slot 11a, contacting and stacking the component 50 with the second prepreg 30. A first gap 11b is defined between the wall of the through-slot 11a and the component 50. When there are multiple through-slots 11a, the multiple through-slots 11a are spaced apart.

[0070] In the pre-pressed component 100, the second and third prepregs 30 and 60 seal the through-slot 11a. The walls of the through-slot 11a, along with the second and third prepregs 30 and 60, form a sealed space within which the component 50 is housed. The third prepreg 60 and second copper foil 70 support and encapsulate the component 50. Furthermore, the third prepreg 60 is in a semi-cured state, becoming fluid during the heat-pressing process to buffer the pressure, thereby effectively protecting the component 50. Furthermore, the insulating resin in the third prepreg 60 becomes fluid during the heat-pressing process, partially flowing into the first gap 11b to fill it, as well as any second gaps that may exist between the component 50 and the third prepreg 60. This helps secure and protect the component 50, improving product reliability. The third prepreg 60 can be a semi-solid sheet made of a reinforcing material (such as fiberglass cloth) impregnated with epoxy resin. The thickness of the third prepreg 60 can be designed based on actual product requirements, such as the thickness of the final PCB structure, and to ensure that the third prepreg 60 can be laminated and in contact with the component 50 after curing. In some embodiments, the coefficient of thermal expansion of the third prepreg 60 after thermal compression curing is within 3 ppm of that of the component 50. This small difference in thermal expansion coefficients helps improve the reliability of the embedded component PCB structure 200 in high-temperature environments. Other fillers can also be added to the third prepreg 60 as needed to enhance performance, such as low-thermal expansion materials to reduce the thermal expansion coefficient, pigments to change the color, and heat dissipation materials such as ceramics to enhance heat dissipation.

[0071] It is understandable that when the thickness of the laminate 11 before hot pressing is greater than the maximum thickness of the component 50 to be embedded, a second gap 11c is provided between the third prepreg 60 and the component 50 in the pre-pressed part. The width of the second gap 11c depends on the difference between the thickness of the laminate 11 before hot pressing and the maximum thickness of the component 50 to be embedded, and specifically can be less than or equal to this difference. In some embodiments, the width of the second gap 11c is greater than or equal to 0.01mm and less than or equal to 0.15mm. In some embodiments, the width of the second gap 11c is 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.08mm, 0.1mm, 0.12mm, or 0.15mm.

[0072] The components of the pre-compression molded part 100 , including the first copper foil 40 , the second prepreg 30 , the laminate 11 , the third prepreg 60 , the second copper foil 70 , the component 50 , and the first gap 11 b , are the same as those described above and are not described again.

[0073] In step S105, the temperature of the thermal compression bonding can be determined based on the required temperature of the prepreg. After the first prepreg 20 is fully cured, a first insulating dielectric layer 201 is formed. After the second prepreg 30 is fully cured, a second insulating dielectric layer 301 is formed. After the third prepreg 60 is fully cured, a third insulating dielectric layer 601 is formed. A fourth insulating dielectric layer 101 is formed in the first gap 11b. The embodiment of the present application achieves component embedding through thermal compression bonding, which simplifies the process, reduces damage to components, improves product yield, and ensures reliability.

[0074] Accordingly, referring to FIG8 , an embodiment of the present application provides a PCB structure 200 with embedded components, comprising a first copper foil 40, a second insulating dielectric layer 301, a stacked structure 21, a third insulating dielectric layer 601, a second copper foil 70, and a fourth insulating dielectric layer 101, which are sequentially stacked, as well as components 50 and metal leads 52.

[0075] The stacked structure 21 includes at least two core plates 10 stacked together, and at least one first insulating dielectric layer 201 arranged between each adjacent two core plates 10 in the at least two core plates 10. The stacked structure 21 has at least one through-groove 11a that penetrates the stacked structure 21 along the thickness direction; the component 50 is arranged in the through-groove 11a, and the component 50 is in contact with and stacked with the second insulating dielectric layer 301 and the third insulating dielectric layer 601. There is a first gap 11b between the component 50 and the groove wall of the through-groove 11a, and the fourth insulating dielectric layer 101 fills the first gap 11b; the metal lead 52 is in contact with and connected to the electrode of the component 50, and is partially exposed for external electrical connection.

[0076] The component 50 is disposed in a closed space formed by the groove wall of the through groove 11 a , the second insulating dielectric layer 301 , and the third insulating dielectric layer 601 .

[0077] In the embodiment of the present application, the stacked structure 21 , ie, the stacked body 11 , is formed by thermal compression bonding, and the thickness of the stacked structure 21 is greater than or equal to the maximum thickness of the component 50 .

[0078] In the embodiment of the present application, the first insulating dielectric layer 201, the second insulating dielectric layer 301, and the third insulating dielectric layer 601 include epoxy resin and a reinforcing material, while the fourth insulating dielectric layer 101 includes epoxy resin and no reinforcing material. It is understood that the first insulating dielectric layer 201 is formed by thermally pressing and curing the first prepreg 20, the second insulating dielectric layer 301 is formed by thermally pressing and curing the second prepreg 30, and the third insulating dielectric layer 601 is formed by thermally pressing and curing the third prepreg 60. The fourth insulating dielectric layer 101 is formed by curing the insulating resin that flows into the first, second, 30, and third prepregs during the thermal pressing process. Therefore, the fourth insulating dielectric layer 101 does not contain any reinforcing material.

[0079] In the embodiment of the present application, the surface of the second insulating dielectric layer 301 close to the component 50 is a plane.

[0080] In some embodiments of the present application, since the thickness of the stack 11 after hot pressing may be equal to the maximum thickness of the component 50 to be embedded, that is, the thickness of the stack structure 21 is equal to the maximum thickness of the component 50, as shown in Figure 8, the surface of the third insulating dielectric layer 601 close to the component 50 is a plane, that is, the interface between the third insulating dielectric layer 601 and the stack structure 21 is on the same plane as the interface between the third insulating dielectric layer 601 and the component 50.

[0081] In some embodiments of the present application, since the thickness of the laminate 11 after hot pressing may be greater than the maximum thickness of the component 50 to be embedded, that is, the thickness of the laminate structure 21 is greater than the maximum thickness of the component 50, as shown in Figure 9, the surface of the third insulating dielectric layer 601 on the side near the component 50 has a protruding layer structure 6011 at a position corresponding to the component 50, which protrudes toward the component 50 and is connected to the component 50. In other words, the interface between the third insulating dielectric layer 601 and the laminate structure 21 is not coplanar with the interface between the third insulating dielectric layer 601 and the component 50. In some embodiments, the difference between the thickness of the laminate structure 21 and the maximum thickness of the component 50, that is, the thickness of the protruding layer structure 6011, can be less than or equal to 0.15 mm. In some embodiments, the difference between the thickness of the stacked structure 21 and the maximum thickness of the component 50, that is, the thickness of the convex structure 6011 can be 0.01mm-0.15mm, for example, 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.08mm, 0.1mm, 0.12mm, and 0.15mm.

[0082] 10 , in some embodiments of the present application, the stacked structure 21 has a plurality of (two or more) through slots 11 a running through the stacked structure 21 along the thickness direction. The plurality of through slots 11 a are arranged at intervals, and each through slot 11 a can accommodate a component 50 .

[0083] The components in the PCB structure 200 with embedded components are the same as those described above and will not be described again here.

[0084] In step S106, the pressed part is windowed to expose the electrodes 51 of the component 50. Specifically, laser windowing can be used to form blind vias that penetrate the second copper foil 70 and the third insulating dielectric layer 601, or penetrate the first copper foil 40 and the second insulating dielectric layer 301, to expose the electrodes 51. It will be appreciated that the location and number of the blind vias can be determined based on the location and number of electrodes on the component 50. The electrodes on the component 50 can be located anywhere on the surface of the component 50, and there can be multiple electrodes. The lateral dimensions of the blind vias can be designed based on actual needs.

[0085] The exposed electrodes 51, i.e., the blind holes, are electroplated with metal leads 52, which can be specifically electroplated copper. The metal leads 52 are used to electrically connect the component 50 to external devices. Using electroplated copper to form the metal leads 52 facilitates further multi-layer rewiring design.

[0086] 11 , an embodiment of the present application further provides a device 300 including the aforementioned PCB structure with embedded components. The device 300 may be a car, a mobile phone, a tablet computer, a laptop computer, a wearable device, or the like.

[0087] The preferred embodiments are described in detail above, but the present invention is not limited to the above-mentioned specific implementation methods. Under the guidance of this application, technicians in this field can also make various forms of specific changes without departing from the scope of protection of this application, which all fall within the scope of protection of the present invention.

[0088] It should be understood that the first, second and various numerical numbers involved in this document are only distinguished for the convenience of description and are not intended to limit the scope of this application.

[0089] In this application, "and / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the related objects are in an "or" relationship.

[0090] In this application, "at least one" means one or more, and "more than one" means two or more. "At least two" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0091] In this application, “-” represents a range value, including the endpoint values ​​at both ends. For example, the value of a can be 0.5-15, which means that the value of a can be between 0.5 and 15, and includes the endpoint values ​​0.5 and 15.

[0092] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claims

1. A method for embedding components, characterized in that: The following steps are involved: stacking at least two core plates, and stacking at least one first prepreg between every two adjacent core plates of the at least two core plates to obtain a stacked body, wherein the stacked body has at least one through groove penetrating the stacked body in a thickness direction; A second prepreg and a first copper foil stacked with the stacked body are sequentially arranged at one end of the through groove; Putting a component into the through groove, the component is in contact with and stacked on the second prepreg, and a first gap is formed between the groove wall of the through groove and the component; A third prepreg and a second copper foil are sequentially arranged at the other end of the through groove to obtain a pre-pressed component, wherein the third prepreg is in contact with and laminated on the laminate; The pre-pressed component is subjected to heat pressing, during which the insulating resin in the first prepreg, the second prepreg and the third prepreg becomes fluid and flows into the first gap and solidifies to fill the first gap, thereby obtaining a pressed component; The pressed part is subjected to a window opening process to expose the electrodes of the components, and metal leads are electroplated at the exposed electrodes to obtain a PCB structure with embedded components.

2. The method for embedding components according to claim 1, characterized in that: The thickness of the stack before hot pressing is greater than the maximum thickness of the component. In the pre-pressed part, a second gap is provided between the third semi-cured sheet and the component. The width of the second gap is greater than or equal to 0.01 mm and less than or equal to 0.15 mm. The thickness of the stack after hot pressing is greater than or equal to the maximum thickness of the component.

3. The method for embedding components according to claim 1, characterized in that: The preparation of the laminate specifically includes: firstly preparing corresponding through holes on the at least two core plates and the at least one first prepreg, respectively, and then laminating the at least two core plates and the at least one first prepreg to obtain the laminate.

4. The method for embedding components according to claim 1, characterized in that: The width of the first gap is less than or equal to 0.15 mm; the thermal expansion coefficient of the laminate after thermal pressing is within 3 ppm of the thermal expansion coefficient of the component.

5. A pre-pressed component, characterized in that: The pre-pressed part includes a first copper foil, a second prepreg, a laminate, a third prepreg and a second copper foil which are stacked in sequence, and components; The stack includes at least two core plates stacked together, and at least one first semi-cured sheet arranged between each adjacent two core plates of the at least two core plates. The stack has at least one through groove running through the stack along the thickness direction, and the second semi-cured sheet and the third semi-cured sheet are used to seal both ends of the through groove. The component is arranged in the through groove, and the component is stacked in contact with the second semi-cured sheet, and a first gap is provided between the groove wall of the through groove and the component.

6. The pre-pressed part according to claim 5, characterized in that: A second gap is provided between the third prepreg and the component; a width of the second gap is greater than or equal to 0.01 mm and less than or equal to 0.15 mm.

7. A PCB structure with embedded components, characterized in that: It includes a first copper foil, a second insulating dielectric layer, a stacked structure, a third insulating dielectric layer and a second copper foil which are stacked in sequence, as well as components, metal leads and a fourth insulating dielectric layer; The stacked structure includes at least two core plates stacked in a stacked manner, and at least one first insulating medium layer arranged between each adjacent two core plates of the at least two core plates, the stacked structure has at least one through groove penetrating the stacked structure along the thickness direction; the component is arranged in the through groove, the component is in contact with and stacked with the second insulating medium layer and the third insulating medium layer, a first gap is provided between the groove wall of the through groove and the component, and the fourth insulating medium layer fills the first gap; the metal lead is in contact with and connected to the electrode of the component, and is partially exposed for external electrical connection.

8. The PCB structure with embedded components as claimed in claim 7, characterized in that: The thickness of the stacked structure is greater than or equal to the maximum thickness of the component; the surface of the second insulating dielectric layer close to the component side is a plane; the surface of the third insulating dielectric layer close to the component side is a plane, or has a convex layer structure protruding toward the side of the component at a position corresponding to the component; the core board includes a non-copper clad board or a copper clad board; the copper clad board includes a substrate and a copper layer arranged on one side or both sides of the substrate; the components include active components or passive components; the first insulating dielectric layer, the second insulating dielectric layer and the third insulating dielectric layer include epoxy resin and reinforcing material, and the fourth insulating dielectric layer includes epoxy resin but does not include reinforcing material.

9. The PCB structure with embedded components as claimed in claim 7, characterized in that: The width of the first gap is less than or equal to 0.15 mm; the thermal expansion coefficient of the stacked structure and the thermal expansion coefficient of the component are within 3 ppm.

10. A device, characterized in that: A PCB structure with embedded components comprising any one of claims 7 to 9.

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