Circuit board and method for manufacturing the same

Abstract

The preparation method comprises the following steps: placing an inner layer circuit unit on a carrier plate, the inner layer circuit unit comprising a substrate layer, a first conductive circuit layer and a containing cavity, the substrate layer comprising oppositely arranged first and second end faces, the first conductive circuit layer being arranged on the second end face, and the containing cavity penetrating through the substrate layer; filling insulating resin in the containing cavity; placing an embedded component on the outer surface of the insulating resin close to the first conductive circuit layer; electrically connecting the embedded component and the first conductive circuit layer by using an electric guide wire; heating the insulating resin to make the embedded component sink into the containing cavity, and continuously heating and solidifying the insulating resin to obtain an insulating resin layer, the insulating resin layer fixing the embedded component in the containing cavity; and removing the carrier plate to obtain a circuit board. The problem of residual glue is solved, and the application further provides a circuit board.

Description

Technical Field

[0001] This application relates to the field of circuit boards, specifically to a method for manufacturing a circuit board and the circuit board itself. Background Technology

[0002] The existing process for embedding embedded components in circuit boards is usually as follows: an inner layer circuit unit is provided, a through cavity is opened in the inner layer circuit unit, a release film is bonded to one side of the inner layer circuit unit, the embedded component is placed in the cavity, and then an outer layer circuit unit is pressed onto the side of the inner layer circuit unit away from the release film, so that the dielectric layer of the outer layer circuit unit penetrates into the cavity to fix the embedded component. After that, the release film is peeled off to obtain a circuit board with embedded embedded components.

[0003] However, since embedded components need to be fixed with a release film, residual adhesive will remain when the release film is peeled off, reducing the yield of the circuit board. Summary of the Invention

[0004] In view of this, this application provides a method for preparing a circuit board without adhesive residue and provides a circuit board.

[0005] This application provides a method for manufacturing a circuit board, comprising:

[0006] An inner layer circuit unit is placed on a carrier plate. The inner layer circuit unit includes a substrate layer, a first conductive circuit layer and a receiving cavity. The substrate layer includes a first end face and a second end face that are disposed opposite to each other. The first conductive circuit layer is disposed on the second end face. The receiving cavity penetrates the substrate layer.

[0007] The cavity is filled with insulating resin.

[0008] The embedded component is placed on the outer surface of the insulating resin near the first conductive line layer.

[0009] The embedded component and the first conductive circuit layer are electrically connected using electrical leads;

[0010] The insulating resin is heated to allow the embedded component to sink into the receiving cavity. The insulating resin is then further heated to cure it and obtain an insulating resin layer. The insulating resin layer fixes the embedded component into the receiving cavity.

[0011] Remove the carrier plate to obtain the circuit board.

[0012] Optionally, after heating the insulating resin to cause the embedded element to sink into the receiving cavity, the insulating resin flows to the second end face, and the electrical lead is at least partially embedded in the insulating resin located on the second end face.

[0013] Optionally, the inner layer circuit unit further includes a second conductive circuit layer, which is disposed on the first end face.

[0014] Optionally, the preparation method further includes, before or after removing the carrier plate:

[0015] At least one first outer layer circuit unit covering the embedded component is laminated on the first conductive circuit layer. The first outer layer circuit unit includes a stacked third conductive circuit layer and a third substrate layer, such that the electrical leads are at least partially embedded in the third substrate layer.

[0016] Optionally, after removing the carrier plate, the preparation method further includes:

[0017] A second outer layer circuit unit is laminated onto the second conductive circuit layer to cover the embedded element. The second outer layer circuit unit includes a fourth conductive circuit layer and a fourth substrate layer stacked together.

[0018] This application also provides a circuit board, which includes an inner circuit unit, an insulating resin layer, embedded components, and electrical leads;

[0019] The inner layer circuit unit includes a substrate layer, a first conductive circuit layer and a receiving cavity. The substrate layer includes a first end face and a second end face disposed opposite to each other. The first conductive circuit layer is disposed on the second end face. The receiving cavity penetrates the substrate layer and the first conductive circuit layer.

[0020] The embedded component is placed inside the receiving cavity, the insulating resin layer fills the receiving cavity, the insulating resin layer is used to fix the embedded component inside the receiving cavity, and the electrical lead wire electrically connects the embedded component and the first conductive line layer.

[0021] Optionally, the insulating resin layer protrudes from the second end face, and the electrical lead is at least partially embedded in the insulating resin layer located on the second end face.

[0022] Optionally, at least one first outer layer circuit unit covering the embedded component is provided on the first conductive circuit layer. The first outer layer circuit unit includes a stacked third conductive circuit layer and a third substrate layer, such that the electrical lead is at least partially embedded in the third substrate layer.

[0023] Optionally, a second conductive line layer is provided on the first end face, and at least one second outer layer line unit covering the embedded component is provided on the second conductive line layer. The second outer layer line unit includes a fourth conductive line layer and a fourth substrate layer stacked together.

[0024] Optionally, the embedded element has pins on its surface facing the first conductive line layer, and the pins are electrically connected to the first conductive line layer through the electrical leads.

[0025] Compared to existing technologies, this application utilizes the fact that the insulating resin can transform from a semi-cured state to a flowable state during gradual heating. This allows the embedded component to settle into the receiving cavity as the insulating resin flows during the gradual heating process. The colloidal insulating resin provides temporary fixation for the embedded component, while the cured insulating resin, as the temperature rises, achieves a fixed connection between the embedded component and the substrate layer. Therefore, it is unnecessary to use a release film to support and fix the embedded component on one side of the receiving cavity, avoiding the problem of residual adhesive caused by peeling off the release film. In addition, this application simplifies the manufacturing process. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the first and second line units being pressed together in an embodiment of this application;

[0027] Figure 2 In order to be in Figure 1 A cross-sectional view of the inner layer circuit unit is obtained by forming receiving cavities on the first circuit unit and the second circuit unit.

[0028] Figure 3 A cross-sectional view showing the inner layer circuit unit placed on a carrier plate and filled with insulating resin;

[0029] Figure 4 In order to be in Figure 3 A cross-sectional view of the embedded component placed in the region corresponding to the receiving cavity, using the insulating resin.

[0030] Figure 5 For use of electrically conductive leads for electrical connection Figure 4 The embedded components and the inner layer circuit unit;

[0031] Figure 6 For curing Figure 5 A cross-sectional view of the insulating resin embedding the embedded element into the receiving cavity;

[0032] Figure 7 In order to be in Figure 6 A cross-sectional view showing the formation of a first outer layer circuit unit and a second outer layer circuit unit on the inner layer circuit unit.

[0033] Explanation of main component symbols

[0034] Circuit board 100

[0035] Inner layer circuit unit 10

[0036] First Line Unit 11

[0037] First substrate layer 111

[0038] First conductive circuit layer 112

[0039] Second line unit 12

[0040] Second substrate layer 121

[0041] Second conductive circuit layer 122

[0042] Substrate layer 13

[0043] First end face 131

[0044] Second end face 132

[0045] Receiving cavity 14

[0046] Insulating resin 20

[0047] 30 bearing plate

[0048] Embedded components 40

[0049] Pin 41

[0050] 50 electrical leads

[0051] Insulating resin layer 60

[0052] First outer layer circuit unit 70

[0053] Third substrate layer 71

[0054] Third conductive circuit layer 72

[0055] Second outer layer circuit unit 80

[0056] Fourth substrate layer 81

[0057] Fourth conductive layer 82

[0058] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0059] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0060] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component.

[0061] This application provides a method for fabricating a circuit board. Depending on different requirements, the order of steps in the fabrication method can be changed, and some steps can be omitted or combined. The fabrication method includes the following steps:

[0062] Step 1: Refer to Figure 1 The first circuit unit 11 and the second circuit unit 12 are laminated to form an inner layer circuit unit 10. The first circuit unit 11 includes a first substrate layer 111 and a first conductive circuit layer 112 stacked together. The second circuit unit 12 includes a second conductive circuit layer 122 and a second substrate layer 121 stacked together. Therefore, the first substrate layer 111 and the second substrate layer 121 together form the substrate layer 13 of the inner layer circuit unit 10, which includes the first conductive circuit layer 112 and the second conductive circuit layer 122. The substrate layer 13 includes a first end face 131 and a second end face 132 disposed opposite to each other. The first conductive circuit layer 112 is disposed on the second end face 132, and the second conductive circuit layer 122 is disposed on the first end face 131.

[0063] It is understood that the inner layer circuit unit 10 can be fabricated using methods known in the art, including forming the first conductive circuit layer 112 and the second conductive circuit layer 122 on a double-sided copper-clad substrate.

[0064] In another embodiment, the inner layer line unit 10 may include only the first line unit 11.

[0065] In another embodiment, the number of the first line unit 11 and the second line unit 12 can be multiple.

[0066] Step Two: Refer to Figure 2 A receiving cavity 14 is formed in the inner layer circuit unit 10. The receiving cavity 14 penetrates the substrate layer 13, the first conductive circuit layer 112 and the second conductive circuit layer 122. The opening method in step two includes, but is not limited to, mechanical opening and laser opening.

[0067] In another embodiment, the receiving cavity 14 may extend only through the first conductive line layer 112 and the first substrate layer 111.

[0068] Step 3: Refer to Figure 3 The inner layer circuit unit 10, after the cavity 14 is formed, is placed on a support plate 30, with the first end face 131 facing the support plate 30. Semi-cured insulating resin 20 is then filled into the cavity 14. In this embodiment, the insulating resin 20 also covers the area of ​​the first end face 131 excluding the second conductive circuit layer 122, and the insulating resin 20 also covers the area of ​​the second end face 132 excluding the first conductive circuit layer 112.

[0069] In another embodiment, the insulating resin 20 may be used to fill only the receiving cavity 14.

[0070] The material of the support plate can be resin, including but not limited to one of polypropylene, polyvinyl chloride and polyurethane.

[0071] Step Four: Refer to Figure 4 The embedded component 40 is placed in the region of the receiving cavity 14, and the insulating resin 20 is placed near the outer surface of the first conductive line layer 112.

[0072] Step 5: Refer to Figure 5 Electrical leads 50 are used to electrically connect the embedded element 40 and the first conductive line layer 112, thereby achieving electrical connection between the embedded element 40 and the inner layer line unit 10.

[0073] Step Six: Refer to Figure 6 The insulating resin 20 is heated to allow the embedded element 40 to sink into the receiving cavity 14. The insulating resin 20 is then heated and cured to obtain an insulating resin layer 60, which fixes the embedded element 40 into the receiving cavity 14.

[0074] Since the insulating resin 20 covers the second end face 132, during the process of the embedded element 40 sinking into the receiving cavity 14, the insulating resin 20 also flows onto the second end face 132. The sinking of the embedded element 40 causes the electrical lead 50 to be at least partially embedded into the insulating resin 20 located on the second end face 132. After the insulating resin 20 is cured, the electrical lead 50 is embedded into the insulating resin layer 60 on the second end face 132. The insulating resin layer 60 on the second end face 132 protects the electrical lead 50 and prevents damage to the electrical lead 50 during subsequent lamination to prepare the outer circuit unit.

[0075] Step Seven: Refer to Figure 7Before or after removing the carrier plate 30, the fabrication method further includes: laminating at least one first outer layer circuit unit 70 covering the embedded element 40 onto the first conductive circuit layer 112, the first outer layer circuit unit 70 comprising a stacked third conductive circuit layer 72 and a third substrate layer 71, such that the electrical lead 50 is at least partially embedded in the third substrate layer 71. Then, the carrier plate 30 is removed. In some other embodiments, the first outer layer circuit unit 70 may not be laminated, and the carrier plate 30 may be removed directly to obtain a circuit board.

[0076] Step seven also includes, after removing the carrier plate 30, pressing at least one second outer layer circuit unit 80 covering the embedded element 40 onto the second conductive circuit layer 122, the second outer layer circuit unit 80 including a stacked fourth conductive circuit layer 82 and a fourth substrate layer 81.

[0077] Specifically, a first single-sided metal-clad substrate (not shown) is provided, comprising a third substrate layer 71 and a first metal layer (not shown). The third substrate layer 71 is laminated onto the first conductive line layer 112, and then the first metal layer is fabricated to form the third conductive line layer 72. When multiple first outer layer circuit units 70 need to be laminated, the above steps of laminating to prepare the third conductive line layer 72 are repeated.

[0078] In some embodiments, the third conductive line layer 72 may be electrically connected to the first conductive line layer 112 via a conductive hole or a conductive post.

[0079] Additionally, a second single-sided metal-clad substrate (not shown) is provided. The second single-sided metal-clad substrate includes a fourth substrate layer 81 and a second metal layer (not shown). The fourth substrate layer 81 is laminated onto the second conductive line layer 122, and the second metal layer is fabricated to form the fourth conductive line layer 82. The first metal layer (not shown) and the second metal layer (not shown) can be copper.

[0080] In some other embodiments, the fourth conductive line layer 82 may be electrically connected to the second conductive line layer 122 via conductive vias or conductive posts.

[0081] This application utilizes the fact that the insulating resin 20 can transform from a semi-cured state to a flowable colloidal state during gradual heating, and finally to an irreversible fully cured state. This allows the embedded element 40 to settle into the receiving cavity 14 as the insulating resin flows during the gradual heating process. The colloidal insulating resin provides temporary fixation for the embedded element 40, while as the temperature rises, the resulting insulating resin layer 60 fixes the embedded element 40 within the receiving cavity 14. Therefore, it eliminates the need for a release film to support and fix the embedded element 40 on one side of the receiving cavity 14, avoiding the residual adhesive problem caused by peeling off the release film. Furthermore, this application simplifies the manufacturing process.

[0082] This application also provides a circuit board 100, with reference to... Figure 7 The circuit board 100 includes an inner layer circuit unit 10, an insulating resin layer 60, an embedded component 40, and electrical leads 50. The inner layer circuit unit 10 includes a substrate layer 13, a first conductive circuit layer 112, and a receiving cavity 14. The substrate layer 13 includes a first end face 131 and a second end face 132 disposed opposite to each other. The first conductive circuit layer 112 is disposed on the second end face 132, and the receiving cavity 14 penetrates the substrate layer 13 and the first conductive circuit layer 112. The embedded component 40 is placed within the receiving cavity 14, and the insulating resin layer 60 fills the receiving cavity 14, serving to fix the embedded component 40 within the receiving cavity 14. The electrical leads 50 electrically connect the embedded component 40 and the first conductive circuit layer 112.

[0083] In some embodiments, refer to Figure 7 The insulating resin layer 60 protrudes from the second end face 132, and the electrical lead 50 is at least partially embedded in the insulating resin layer 60 located on the second end face 132.

[0084] In some embodiments, refer to Figure 7 At least one first outer circuit unit 70 covering the embedded element 40 is provided on the first conductive circuit layer 112. The first outer circuit unit 70 includes a third conductive circuit layer 72 and a third substrate layer 71 stacked together, such that the electrical lead 50 is at least partially embedded in the third substrate layer 71.

[0085] In some embodiments, refer to Figure 7 A second conductive line layer 122 is provided on the first end face 131, and at least one second outer layer circuit unit 80 covering the embedded component 40 is provided on the second conductive line layer 122. The second outer layer circuit unit 80 includes a fourth conductive line layer 82 and a fourth substrate layer 81.

[0086] In other embodiments, the first conductive line layer 112 and the second conductive line layer 122 can be electrically connected through conductive holes and conductive posts. The first conductive line layer 112 can be electrically connected to the third conductive line layer 72 through conductive holes or conductive posts, and the second conductive line layer 122 can be electrically connected to the fourth conductive line layer 82 through conductive holes or conductive posts.

[0087] In other embodiments, reference is made to Figure 7 The embedded component 40 has pins 41 on its surface facing the first conductive line layer 112, and the pins 41 are electrically connected to the first conductive line layer 112 through the electrical lead 50.

[0088] In the above embodiments, the materials of the first substrate layer 111, the second substrate layer 121, the third substrate layer 71, and the fourth substrate layer 81 can be insulating resins, specifically at least one of polypropylene (PP), polyimide (PI), liquid crystal line polymer (LCP), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). The materials of the first conductive circuit layer 112, the second conductive circuit layer 122, the third conductive circuit layer 72, and the fourth conductive circuit layer 82 can be copper.

[0089] In the above embodiments, the insulating resin material can be at least one of Ajinomoto ABF:GXGX-T31, GX13, and GX92.

[0090] The above description is merely an optimized implementation of this application, and its application should not be limited to this specific implementation. Other modifications and alterations made by those skilled in the art based on the technical concept of this application should fall within the protection scope of this application.

Claims

1. A method for manufacturing a circuit board, characterized in that, include: An inner layer circuit unit is placed on a carrier plate. The inner layer circuit unit includes a substrate layer, a first conductive circuit layer and a receiving cavity. The substrate layer includes a first end face and a second end face that are disposed opposite to each other. The first conductive circuit layer is disposed on the second end face. The receiving cavity penetrates the substrate layer. The cavity is filled with insulating resin. The embedded component is placed on the outer surface of the insulating resin near the first conductive line layer. The embedded component and the first conductive circuit layer are electrically connected using electrical leads; The insulating resin is heated to allow the embedded component to sink into the receiving cavity. The insulating resin is then further heated to cure it and obtain an insulating resin layer. The insulating resin layer fixes the embedded component into the receiving cavity. Remove the carrier plate to obtain the circuit board.

2. The method for manufacturing a circuit board as described in claim 1, characterized in that, After heating the insulating resin to cause the embedded element to sink into the receiving cavity, the insulating resin flows to the second end face, and the electrical lead is at least partially embedded in the insulating resin located on the second end face.

3. The method for manufacturing a circuit board as described in claim 1, characterized in that, The inner layer circuit unit further includes a second conductive circuit layer, which is disposed on the first end face.

4. The method for manufacturing a circuit board as described in claim 1, characterized in that, Before or after removing the support plate, the preparation method further includes: At least one first outer layer circuit unit covering the embedded component is laminated on the first conductive circuit layer. The first outer layer circuit unit includes a stacked third conductive circuit layer and a third substrate layer, such that the electrical leads are at least partially embedded in the third substrate layer.

5. The method for manufacturing a circuit board as described in claim 3, characterized in that, After removing the support plate, the preparation method further includes: A second outer layer circuit unit is laminated onto the second conductive circuit layer to cover the embedded element. The second outer layer circuit unit includes a fourth conductive circuit layer and a fourth substrate layer stacked together.

Images