Method for manufacturing circuit board
By setting a peelable carrier board in the opening of the outer substrate to form an open cover, the problems of increased thickness and decreased bending resistance caused by the addition of circuit board layers are solved, realizing high density, miniaturization and thinness of circuit boards, and improving stability and bending life.
Patent Information
- Application Number
- CN202410865582.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-28
- Publication Date
- 2025-12-30
AI Technical Summary
In existing technologies, the process of adding layers to circuit boards leads to an increase in thickness, which reduces the bending resistance of flexible circuit boards, making it difficult to achieve the goals of high density, miniaturization, and thinness.
A peelable carrier board is placed inside the opening of the outer substrate and pressed onto the inner circuit layer of the core board through a connecting layer. The peelable carrier board is removed to form an opening, forming a flat and smooth connecting layer that provides a physical barrier to protect the inner circuit layer.
It improves the stability and reliability of the circuit board, reduces the thickness, enhances bending life and reliability, reduces manufacturing steps, and prevents environmental factors from corroding the inner circuit layers.
Smart Images
Figure CN121240328A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of manufacturing circuit board, and particularly relates to a manufacturing method of circuit board. BACKGROUND
[0002] In the electronic industry, the industry generally pursues high-density lines, because only the high-density, miniaturization, and thinness of the printed circuit board can make it possible to achieve the goal of lightening the terminal application.
[0003] However, due to the limited wiring area in the circuit board, it is necessary to increase the layers of the circuit board. In the process of increasing the layers, an adhesive material such as pure glue is used to bond and fix the multi-layer circuit board. After the increase of the layers is completed, a certain material needs to be added to the outermost layer of the circuit board for surface shielding, which inevitably further increases the thickness of the circuit board. At the same time, as for the flexible circuit board, when the thickness of the circuit board increases, its resistance to winding and folding will decrease, which will result in the loss or reduction of the advantages of the flexible circuit board. SUMMARY
[0004] To solve the above problems of the prior art, the present application provides a manufacturing method of circuit board.
[0005] A manufacturing method of circuit board, comprising the steps of: providing an outer substrate assembly, the outer substrate assembly comprising an outer substrate, a peelable carrier plate, and a connecting layer, the outer substrate being provided with a first opening, the peelable carrier plate being arranged in the first opening, the outer side of the outer substrate being flush with the outer side of the peelable carrier plate, one side of the connecting layer being arranged on one side of the outer substrate and the peelable carrier plate; pressing a core plate on the outer substrate, the core plate comprising at least one inner circuit layer, the other side of the connecting layer covering the inner circuit layer, to obtain a circuit board intermediate body; and removing the peelable carrier plate to form an opening in the circuit board intermediate body.
[0006] In some embodiments, the peelable carrier plate comprises a substrate layer, a first conductive layer, and a second conductive layer arranged in sequence, the first conductive layer being peelably connected to the second conductive layer, one side of the second conductive layer opposite to the first conductive layer being connected to the connecting layer, and the step of removing the peelable carrier plate comprises: arranging a first slot on the periphery of the peelable carrier plate, the first slot penetrating the substrate layer; arranging a second slot on the bottom of the first slot, the second slot penetrating at least the first conductive layer; peeling part of the first conductive layer; and removing the second conductive layer and another part of the first conductive layer.
[0007] In some embodiments, the outer substrate includes an outer insulating layer and an outer conductive layer disposed on the outer insulating layer, the outer conductive layer is disposed side by side with the substrate layer, the outer insulating layer is disposed side by side with the first conductive layer and the second conductive layer, the manufacturing method further includes the steps of: disposing a second opening on the outer substrate assembly, the second opening penetrates the outer conductive layer, the outer insulating layer and the connecting layer, and part of the inner circuit layer is exposed in the second opening. A conductive body is disposed in the second opening, the conductive body is electrically connected to the outer conductive layer and the inner circuit layer. The outer conductive layer is etched to form an outer circuit layer, and the conductive body is electrically connected to the outer circuit layer and the inner circuit layer.
[0008] In some embodiments, the step of "disposing a first slot on the periphery of the peelable carrier plate" is performed synchronously with the step of "disposing a second opening on the outer substrate assembly".
[0009] In some embodiments, the step of "etching the outer conductive layer to form an outer circuit layer" is performed synchronously with the step of "disposing a second slot on the bottom of the first slot".
[0010] In some embodiments, a cover film is laminated on the outer circuit layer.
[0011] In some embodiments, the inner circuit layer includes a plurality of gold fingers, the gold fingers are disposed corresponding to the first opening, and the method further includes the steps of: disposing a dry film on the outer side of the plurality of gold fingers before the step of "laminating a core plate on the outer substrate". After the step of "removing the peelable carrier plate", the method further includes the steps of: removing the dry film to expose the plurality of gold fingers on the bottom of the opened cover.
[0012] In some embodiments, the method further includes the step of: disposing a protective layer on the outer side of the plurality of gold fingers exposed on the bottom of the opened cover.
[0013] In some embodiments, the manufacturing method of the outer substrate assembly includes the steps of: providing a single-sided copper-clad substrate, the single-sided copper-clad substrate includes the outer insulating layer and the outer conductive layer disposed on one side of the outer insulating layer. The first opening is disposed on the single-sided copper-clad substrate, the first opening penetrates the outer insulating layer and the outer conductive layer. The peelable carrier plate is disposed in the first opening, the substrate layer of the peelable carrier plate is disposed side by side with the outer conductive layer, and the first conductive layer and the second conductive layer of the peelable carrier plate are disposed side by side with the outer insulating layer. The connecting layer is laminated on the outer insulating layer and the second conductive layer to obtain the outer substrate assembly.
[0014] In some embodiments, the material of the connecting layer includes epoxy resin.
[0015] Compared to existing technologies, the circuit board manufacturing method provided in this application involves placing the peelable carrier plate in the first opening of the outer substrate, then pressing the peelable carrier plate onto the inner circuit layer of the core board through the connecting layer, and finally removing the peelable carrier plate to form an opening. This method facilitates obtaining a flat and smooth connecting layer on the inner circuit layer of the core board. The connecting layer can provide a physical barrier for the inner circuit layer of the core board, effectively preventing environmental factors such as moisture, dust, chemicals, and oxidation from eroding the inner circuit layer. This improves the stability and reliability of the circuit board under various working conditions. It also facilitates the reduction of the thickness of the circuit board at the opening, thereby reducing the bending radius of the circuit board during bending and improving the bending life and reliability of the circuit board. Attached Figure Description
[0016] Figure 1 This is a cross-sectional schematic diagram of a single-sided copper-clad substrate provided in an embodiment of this application.
[0017] Figure 2 for Figure 1 Therefore, a cross-sectional schematic diagram of the outer substrate is obtained by setting the first opening on the single-sided copper-clad substrate.
[0018] Figure 3 for Figure 2 The diagram shows a cross-section of the first opening after a peelable carrier plate has been installed.
[0019] Figure 4 For pressing Figure 3 A cross-sectional schematic diagram of the outer substrate assembly formed after the outer substrate, peelable carrier plate, and connecting layer are shown.
[0020] Figure 5 This is a cross-sectional schematic diagram of a core board provided in an embodiment of this application.
[0021] Figure 6 This is a cross-sectional schematic diagram of the circuit board intermediate obtained after pressing the core board and the two outer substrate assemblies.
[0022] Figure 7 for Figure 6 The diagram shows a cross-sectional view of the circuit board intermediate body after the second opening and the first slot are set.
[0023] Figure 8 for Figure 7 The diagram shows a cross-sectional view of the outer side of the circuit board intermediate after the first dry film is applied.
[0024] Figure 9 for Figure 8 The diagram shows a cross-section of the second opening after the conductor is installed.
[0025] Figure 10 forFigure 9 The diagram shows a cross-section of the connecting pad after the second dry film has been installed.
[0026] Figure 11 For etching Figure 10 The diagram shows a cross-sectional view of the outer conductive layer after it has been formed into the outer circuit layer.
[0027] Figure 12 To remove Figure 11 The diagram shows a partial cross-sectional view of the second conductive layer and a portion of the substrate layer.
[0028] Figure 13 To remove Figure 12 The diagram shows a cross-sectional view of the circuit board obtained by opening the cover after partially forming the first conductive layer.
[0029] Figure 14 Two core plates are pressed together as provided in another embodiment of this application. Figure 4 A cross-sectional schematic diagram of the outer substrate assembly is shown.
[0030] Figure 15 To remove Figure 14 The diagram shows a cross-section of the peelable carrier plate.
[0031] Figure 16 To remove Figure 15 The diagram shows a cross-section of the removable layer to expose multiple gold fingers.
[0032] Figure 17 for Figure 16 The diagram shows a cross-section of multiple gold fingers after a protective layer has been applied.
[0033] Explanation of main component symbols
[0034] Circuit board 100
[0035] Outer substrate assembly 10
[0036] outer substrate 11
[0037] Peelable carrier plate 12
[0038] Connection layer 13
[0039] First opening 111
[0040] Single-sided copper-clad substrate 20
[0041] Outer insulation layer 21
[0042] Outer conductive layer 22
[0043] Substrate layer 121
[0044] First conductive layer 122
[0045] Second conductive layer 123
[0046] Core board 30
[0047] Inner insulating layer 31
[0048] Inner circuit layer 32
[0049] Golden Finger 321
[0050] Separable layer 34
[0051] Circuit board intermediate 40
[0052] First slot 41
[0053] Second opening 42
[0054] First dry film 43
[0055] First window opening 431
[0056] Second dry film 52
[0057] Second window 521
[0058] Outer circuit layer 53
[0059] Second slot 44
[0060] Annular through groove 45
[0061] 60 with the lid open
[0062] Covering membrane 70
[0063] Third window 701
[0064] Fourth window 702
[0065] Adhesive layer 71
[0066] First protective layer 72
[0067] Second protective layer 321a
[0068] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation
[0069] 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.
[0070] Please see Figures 1 to 13One embodiment of this application provides a method for manufacturing a circuit board 100, including the following steps:
[0071] S1: Please see Figure 4 An outer substrate assembly 10 is provided, comprising an outer substrate 11, a peelable carrier plate 12, and a connecting layer 13. The outer substrate 11 has a first opening 111 extending through it, and the peelable carrier plate 12 is disposed within the first opening 111. The outer surface of the outer substrate 11 is flush with the outer surface of the peelable carrier plate 12, and one side of the connecting layer 13 covers both the flush outer surface of the outer substrate 11 and the outer surface of the peelable carrier plate 12. A gap J exists between the peelable carrier plate 12 and the first opening 111, and a portion of the connecting layer 13 fills the gap J. The connecting layer 13 is made of a pure adhesive, such as epoxy resin, acrylic resin, or polyurethane resin.
[0072] In this embodiment, the manufacturing method of the outer substrate assembly 10 in step S1 includes the following steps:
[0073] S11: Please refer to Figure 1 A single-sided copper-clad substrate 20 is provided, the single-sided copper-clad substrate 20 including an outer insulating layer 21 and an outer conductive layer 22 disposed on one side of the outer insulating layer 21.
[0074] S12: Please refer to Figure 2 The first opening 111 is provided on the single-sided copper-clad substrate 20, and the first opening 111 penetrates the outer insulating layer 21 and the outer conductive layer 22 to obtain the outer substrate 11. The first opening 111 is located approximately in the middle of the single-sided copper-clad substrate 20. The first opening 111 is formed by mechanical drilling, laser drilling, or chemical etching.
[0075] S13: Please see Figure 3 The peelable carrier plate 12 is disposed within the first opening 111. The peelable carrier plate 12 includes a substrate layer 121, a first conductive layer 122, and a second conductive layer 123 stacked sequentially. The first conductive layer 122 is peelably connected to the second conductive layer 123. The side of the second conductive layer 123 facing away from the first conductive layer 122 is connected to the connecting layer 13. Both the first conductive layer 122 and the second conductive layer 123 are copper layers. A peelable adhesive layer (not shown) is provided between the first conductive layer 122 and the second conductive layer 123. The first conductive layer 122 and the second conductive layer 123 can be separated by removing this peelable adhesive layer.
[0076] In this embodiment, the substrate layer 121 of the peelable carrier 12 is arranged side by side with the outer conductive layer 22, and the first conductive layer 122 and the second conductive layer 123 of the peelable carrier 12 are arranged side by side with the outer insulating layer 21. This facilitates separating the subsequent etching process of the outer conductive layer 22 from the etching process of the first conductive layer 122 and the second conductive layer 123, improving control over different etching processes and helping to reduce errors and defects in different etching processes.
[0077] S14: Please see Figure 4 The connecting layer 13 is pressed onto the outer insulating layer 21 and the second conductive layer 123, and the connecting layer 13 connects the outer substrate 11 and the peelable carrier plate 12 into a whole to obtain the outer substrate assembly 10.
[0078] S2: Please see Figure 5 and Figure 6 An outer substrate assembly 10 is pressed onto each of the opposite sides of a core board 30. The core board 30 includes an inner insulating layer 31 and inner circuit layers 32 disposed on opposite sides of the inner insulating layer 31. The connecting layer 13 covers the inner circuit layers 32 on the side opposite to the outer substrate 11 and the peelable carrier board 12, thus obtaining a circuit board intermediate body 40. Since neither the core board 30 nor the outer substrate assembly 10 has cavities, pressure can be uniformly transmitted during the pressing process of the core board 30 and the outer substrate assembly 10. The connecting layer 13, made of pure adhesive, is not prone to deformation or flow problems. In addition, the connecting layer 13, made of pure adhesive, has good elasticity and can absorb and disperse external forces or internal stresses, reducing damage to the inner circuit layers 32 caused by bending, stretching, or vibration, and protecting the core board 30 from damage.
[0079] Please see Figure 14 In another embodiment of this application, the inner circuit layer 32 includes a plurality of gold fingers 321. The plurality of gold fingers 321 are disposed corresponding to the first opening 111, and a separable layer 34 covers the outer side of the plurality of gold fingers 321. The separable layer 34 connects to a portion of the second conductive layer 123. The separable layer 34 is a photosensitive material.
[0080] S3: Please see Figure 7A first slot 41 and a second opening 42 are provided in the intermediate body 40 of the circuit board. The first slot 41 is located near the periphery of the peelable carrier board 12 and penetrates the substrate layer 121. A portion of the first conductive layer 122 is exposed at the bottom of the first slot 41. The second opening 42 is located in the outer substrate 11 and penetrates the outer conductive layer 22, the outer insulating layer 21, and the connecting layer 13. A portion of the inner circuit layer 32 is exposed at the bottom of the second opening 42.
[0081] S4: Please see Figure 8 A first dry film 43 is provided on the side of the outer substrate assembly 10 away from the core board 30. The first dry film 43 covers the substrate layer 121 of the peelable carrier board 12 and covers the first slot 41. The first dry film 43 is provided with a first window 431, and the second opening 42 and part of the outer conductive layer 22 are exposed in the first window 431.
[0082] S5: Please see Figure 9 A connecting pad 50 is electroplated within the first opening 431, the connecting pad 50 covering the second opening 42, and a portion of the connecting pad 50 filling the second opening 42 to form a conductor 51. The conductor 51 electrically connects the outer conductive layer 22 and the inner circuit layer 32. Then, the first dry film 43 is removed.
[0083] S6: Please see Figure 10 A second dry film 52 is disposed on the side of the outer substrate assembly 10 opposite to the core board 30. The second dry film 52 has a plurality of second openings 521, and a portion of the outer conductive layer 22 is exposed in the plurality of second openings 521. The first slot 41 is exposed in the plurality of second openings 521. That is, a portion of the first conductive layer 122 is exposed in the second openings 521.
[0084] S7: See also Figure 11The outer conductive layer 22 exposed in the plurality of second openings 521 is etched away, and then the second dry film 52 is removed to form an outer circuit layer 53. Simultaneously, a portion of the first conductive layer 122 and a portion of the second conductive layer 123 exposed in the second openings 521 are etched away, thereby forming a second opening 44 at the bottom of the first opening 41. The second opening 44 penetrates the first conductive layer 122 and the second conductive layer 123, so that a portion of the connecting layer 13 is exposed at the bottom of the second opening 44. Thus, an annular through-groove 45 is formed near the periphery of the peelable carrier 12. The annular through-groove 45 includes the first opening 41 and the second opening 44 connecting the first opening 41, and a portion of the connecting layer 13 is exposed at the bottom of the annular through-groove 45. In other embodiments of this application, the second opening 44 penetrates the first conductive layer 122, and a portion of the second conductive layer 123 is exposed at the bottom of the second opening 44.
[0085] S8: Please see Figure 12 The first conductive layer 122 and the second conductive layer 123 within the annular through-groove 45 are separated, such that the first conductive layer 122 and the substrate layer 121 corresponding to the first conductive layer 122 are removed. The remaining portion of the second conductive layer 123 is connected to the connecting layer 13. Additionally, a portion of the first conductive layer 122, a portion of the second conductive layer 123, and a portion of the substrate layer 121 outside the annular through-groove 35 are retained.
[0086] S9: Please see Figure 13 The second conductive layer 123 inside the annular through-groove 45, and a portion of the first conductive layer 122 and a portion of the second conductive layer 123 outside the annular through-groove 45 are etched away, thereby forming a cover 60 on the outer substrate assembly 10. The connecting layer 13 is exposed at the bottom of the cover 60. In addition, a portion of the substrate layer 121 remains on the sidewall of the cover 60. The connecting layer 13, made of pure adhesive, has good electrical insulation properties, which can effectively prevent short circuits, leakage and other problems, and ensure the safe operation of the inner circuit layer 32 it covers in complex electronic devices. In addition, pure adhesive also has an electromagnetic shielding effect, which can help reduce electromagnetic interference and improve electromagnetic compatibility.
[0087] In other embodiments of this application, the annular through groove 45 is located at the periphery of the peelable carrier plate 12, so in step S9, the sidewall of the opening cover 60 will not retain part of the substrate layer 121.
[0088] Please see Figure 15 and Figure 16In another embodiment of this application, the removable layer 34 is exposed at the bottom of the cover 60. The plurality of gold fingers 321 are then exposed at the bottom of the cover 60 by removing the removable layer 34. Specifically, the removable layer 34 is removed by chemical etching.
[0089] S10: Please see again Figure 13 A cover film 70 is laminated onto the outer circuit layer 53. The cover film 70 has a third window 701 and a fourth window 702. The third window 701 exposes the connecting pad 50, and the fourth window 702 exposes the cover 60, thus obtaining the circuit board 100. The cover film 70 includes an adhesive layer 72 and a first protective layer 71. The adhesive layer 72 connects the first protective layer 71 and the outer circuit layer 53. The adhesive layer 72 is made of epoxy resin, and the first protective layer 71 is made of polyimide.
[0090] Please see Figure 17 In another embodiment of this application, the method further includes the step of: providing a second protective layer 321a on the outer surface of the plurality of gold fingers 321, wherein the material of the second protective layer 321a includes a nickel-gold alloy.
[0091] Compared with the prior art, the circuit board 100 manufacturing method provided in this application has the following advantages:
[0092] (i) By setting the peelable carrier plate 12 in the first opening 111 of the outer substrate 11, and then pressing the connecting layer 13 onto the inner circuit layer 32 of the core board 30 through the peelable carrier plate 12, and finally removing the peelable carrier plate 12 to form the cover 60, it is beneficial to obtain a flat and smooth connecting layer 13 on the inner circuit layer 32 of the core board 30. The connecting layer 13 can provide a physical barrier for the inner circuit layer 32 of the core board 30, effectively preventing the erosion of the inner circuit layer 32 by environmental factors such as moisture, dust, chemicals, and oxidation, thereby improving the stability and reliability of the circuit board 100 under various working conditions. At the same time, it is also beneficial to reduce the thickness of the circuit board 100 in the cover 60, which in turn helps to reduce the bending radius during bending, thereby improving the bending life and reliability of the circuit board 100.
[0093] (ii) By setting the peelable carrier plate 12 in the first opening 111 of the outer substrate 11, and then pressing the connecting layer 13 onto the inner circuit layer 32 of the core board 30 through the peelable carrier plate 12, and finally removing the peelable carrier plate 12 to form the cover 60, the entire process does not require pre-opening the connecting layer 13, which helps to save manufacturing steps of the circuit board 100.
[0094] (iii) Before the peelable carrier plate 12 is removed, the connecting layer 13 is in direct contact with the second conductive layer 123, so that the side of the connecting layer 13 in contact with the second conductive layer 123 has a high degree of flatness, which helps to reduce the surface polishing treatment of the outer surface of the connecting layer 13 exposed on the opening 60 after the peelable carrier plate 12 is removed.
[0095] 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 of manufacturing a circuit board, characterized by, The method comprises steps of: providing an outer substrate assembly, the outer substrate assembly comprising an outer substrate, a peelable carrier and a connecting layer, the outer substrate being provided with a first opening, the peelable carrier being arranged in the first opening, an outer side of the outer substrate being flush with an outer side of the peelable carrier, one side of the connecting layer being arranged on one side of the outer substrate and the peelable carrier; pressing a core board to the outer substrate, the core board comprising at least one inner circuit layer, the other side of the connecting layer covering the inner circuit layer, to obtain a circuit board intermediate body; removing the peelable carrier to form an opening in the circuit board intermediate body.
2. The production method according to claim 1, wherein The peelable carrier comprises a substrate layer, a first conductive layer and a second conductive layer arranged in sequence, the first conductive layer being peelably connected to the second conductive layer, one side of the second conductive layer away from the first conductive layer being connected to the connecting layer, and the step of removing the peelable carrier comprises: arranging a first slot at a periphery of the peelable carrier, the first slot penetrating the substrate layer; arranging a second slot at a bottom of the first slot, the second slot penetrating at least the first conductive layer; peeling part of the first conductive layer, and removing the second conductive layer and another part of the first conductive layer.
3. The production method according to claim 2, wherein The outer substrate comprises an outer insulating layer and an outer conductive layer arranged on an outer side of the outer insulating layer, the outer conductive layer being arranged side by side with the substrate layer, the outer insulating layer being arranged side by side with the first conductive layer and the second conductive layer, and the method further comprises steps of: arranging a second opening in the outer substrate assembly, the second opening penetrating the outer conductive layer, the outer insulating layer and the connecting layer, part of the inner circuit layer being exposed in the second opening; arranging a conductive body in the second opening, the conductive body being electrically connected to the outer conductive layer and the inner circuit layer; etching the outer conductive layer to form an outer circuit layer, the conductive body being electrically connected to the outer circuit layer and the inner circuit layer.
4. The production method according to claim 3, wherein The step of arranging the first slot at the periphery of the peelable carrier is performed synchronously with the step of arranging the second opening in the outer substrate assembly.
5. The production method according to claim 3, wherein The step of etching the outer conductive layer to form the outer circuit layer is performed synchronously with the step of arranging the second slot at the bottom of the first slot.
6. The production method according to claim 3, wherein Pressing a cover film to the outer circuit layer.
7. The production method according to claim 3, wherein The inner circuit layer comprises a plurality of gold fingers, the gold fingers being arranged corresponding to the first opening, and the method further comprises, before the step of pressing the core board to the outer substrate, steps of: arranging dry films on outer sides of the gold fingers; and after the step of removing the peelable carrier, the method further comprises a step of: removing the dry films to expose the gold fingers at a bottom of the opening.
8. The production method according to claim 7, wherein The method further comprises a step of:
9. The production method according to claim 2, wherein arranging a protective layer on outer sides of the gold fingers exposed at the bottom of the opening. The method of manufacturing the outer substrate assembly comprises steps of: providing a single-sided copper-clad substrate, the single-sided copper-clad substrate comprising the outer insulating layer and the outer conductive layer arranged on one side of the outer insulating layer; The first opening is arranged on the single-sided copper-clad substrate, and the first opening penetrates the outer insulating layer and the outer conductive layer; The peelable carrier plate is arranged in the first opening, and the substrate layer of the peelable carrier plate is arranged side by side with the outer conductive layer, and the first conductive layer and the second conductive layer of the peelable carrier plate are arranged side by side with the outer insulating layer; The connecting layer is laminated on the outer insulating layer and the second conductive layer to obtain the outer substrate assembly.
10. The production method according to claim 9, wherein The material of the connecting layer comprises epoxy resin.