Circuit board structure with stepped semi-embedded gold fingers and method of making same

Abstract

The application provides a manufacturing method of a circuit board structure with stepped semi-embedded gold fingers, comprising the following steps: a copper-clad substrate comprises a base material layer and a first metal layer arranged on the surface of the base material layer; a plurality of grooves are formed through the base material layer to form a groove area; the first metal layer is arranged on the base material layer except the groove area; and a gold finger pattern is formed in the groove; a first solder mask layer, a flow-free prepreg and a press plate are sequentially arranged on the surface of the copper-clad substrate; the first solder mask layer has a first opening; the gold finger pattern is exposed from the first opening; the flow-free prepreg is provided with a second opening corresponding to the first opening; part of the press plate is removed corresponding to the second opening to form a window; the gold finger pattern is exposed from the window; the gold finger pattern is exposed corresponding to the first opening; and a nickel-gold layer is arranged on the surface of the gold finger pattern to form a gold finger. The application also provides a circuit board structure with stepped semi-embedded gold fingers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board manufacturing, and particularly relates to a circuit board structure with a stepped semi-embedded gold finger and a manufacturing method thereof. BACKGROUND

[0002] In order to meet market needs, a circuit board with a stepped groove and a gold finger arranged on the bottom surface of the stepped groove, i.e., a stepped gold finger circuit board, needs to be manufactured. A conventional manufacturing method of the stepped gold finger circuit board is as follows: first, a gold finger pattern is manufactured on the bottom surface of the stepped groove; then, a high-temperature-resistant adhesive tape is attached to the surface of the gold finger pattern; then, a plurality of layers of circuit substrates are laminated on the surface of the high-temperature-resistant adhesive tape; after the plurality of layers of circuit substrates are pressed together, the circuit substrates above the high-temperature-resistant adhesive tape are removed by cutting (for example, CNC milling cutter cutting); finally, the high-temperature-resistant adhesive tape is removed, and the gold finger pattern is electroplated with nickel and gold, so as to obtain the stepped gold finger circuit board. This manufacturing method is very complicated, and especially, the attachment and removal of the high-temperature-resistant adhesive tape need to be performed manually, which is low in production efficiency. The high-temperature-resistant adhesive tape is prone to aging and sticking under high temperature and high pressure, and is not easy to be removed from the surface of the gold finger, which is prone to polluting the gold finger and causing poor quality of the gold finger. Moreover, the gold finger is arranged only on the bottom surface of the stepped groove, and has poor adhesion, which may cause abnormal falling off after being plugged in and out for many times. SUMMARY

[0003] In order to solve the above problems, the purpose of the present application is to provide a manufacturing method of a circuit board structure with a stepped semi-embedded gold finger, which is simple in process, has no residual adhesive pollution, and has strong adhesion of the gold finger.

[0004] An embodiment of the present application provides a manufacturing method of a circuit board structure with a stepped semi-embedded gold finger, which comprises the following steps:

[0005] A copper-clad substrate is provided, which comprises a substrate layer and a first metal layer arranged on the surface of the substrate layer. A plurality of grooves are arranged through part of the substrate layer to form a groove region. The first metal layer is arranged on the part of the substrate layer other than the groove region.

[0006] A first copper layer is formed on the surface of the first metal layer and the groove region. The first copper layer is partially filled into the grooves to form a gold finger pattern.

[0007] A first anti-soldering layer is arranged on the surface of the first copper layer. The first anti-soldering layer has a first opening. The gold finger pattern is exposed from the first opening.

[0008] A no-flow adhesive prepreg and a pressing plate are laminated on the surface of the first anti-soldering layer. The no-flow adhesive prepreg has a second opening corresponding to the first opening.

[0009] Corresponding to the second opening removal part of the press plate, a window is formed, and the gold finger pattern is exposed by the window;

[0010] Corresponding to the first opening, part of the first copper layer in the groove area is removed to expose the gold finger pattern;

[0011] An electro-nickel-gold layer is arranged on the surface of the gold finger pattern to form a gold finger, that is, a circuit board structure with a stepped semi-embedded gold finger is obtained.

[0012] The application also provides a circuit board structure with a stepped semi-embedded gold finger, comprising a substrate layer, a gold finger, a first circuit layer, a first solder mask layer, a no-flow prepreg, and a press plate. The gold finger comprises a gold finger pattern embedded in the substrate layer and an electro-nickel-gold layer arranged on the surface of the gold finger pattern and protruding from the surface of the substrate layer. The first circuit layer, the first solder mask layer, the no-flow prepreg, and the press plate are sequentially arranged on the surface of the substrate layer provided with the gold finger and avoid the gold finger. The gold finger is electrically connected to the first circuit layer.

[0013] Compared with the prior art, the manufacturing method of the circuit board structure with a stepped semi-embedded gold finger provided by the application has the following advantages:

[0014] (1) By semi-embedding the gold finger in the substrate layer, the embedding adhesion can be increased, and the risk of separation caused by multiple plugging and unplugging can be reduced.

[0015] (2) By pre-opening a second opening in the no-flow prepreg, only part of the press plate needs to be removed to continue processing the exposed gold finger pattern, without the need for high-precision depth-determining and slotting operations, and the process is simple.

[0016] (3) By reducing the copper process to expose the gold finger pattern, and then arranging an electro-nickel-gold layer to form the gold finger, the need for protective tape on the surface of the gold finger is eliminated, the process of applying, pressing, and tearing off the tape is saved, and there is no residual glue stain on the gold finger, which ensures the quality.

[0017] (4) By using a no-flow prepreg and forming a solder mask buffer zone corresponding to the area of the first solder mask layer near the gold finger pattern, the no-flow prepreg can be prevented from being contaminated during pressing. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A cross-sectional view of a copper-clad substrate provided by an embodiment of the application is shown.

[0019] Figure 2 A partial top view of a copper-clad substrate is shown. Figure 1

[0020] ​Figure 3 For Figure 1 The cross-sectional schematic diagram of the first intermediate body is obtained after a gold finger pattern is formed by electroplating on one side of the copper-clad substrate.

[0021] Figure 4 for Figure 3 A partial top view of the first intermediate body is shown.

[0022] Figure 5 For the general Figure 3 The cross-sectional schematic diagram of the second intermediate body obtained after the first copper layer and the first metal layer are patterned to form the first circuit layer is shown.

[0023] Figure 6 for Figure 5 A partial top view of the second intermediate body is shown.

[0024] Figure 7 For Figure 5 The schematic cross-sectional view of the third intermediate body is shown after the first solder mask layer is provided on the surface of the first circuit layer.

[0025] Figure 8 for Figure 7 A partial top view of the third intermediate body is shown.

[0026] Figure 9 For Figure 7 The schematic cross-sectional view of the fourth intermediate body is shown after the surface of the first solder mask is pressed with a non-flow prepreg and a double-sided copper clad laminate.

[0027] Figure 10 For Figure 9 The fourth intermediate body is shown as a cross-sectional schematic diagram after a through hole is opened through it.

[0028] Figure 11 For the general Figure 9 The fourth intermediate is shown as a schematic cross-sectional view after the entire board is electroplated to form a third copper layer, a fourth copper layer and a hole wall copper layer.

[0029] Figure 12 For the general Figure 11 The diagram shows a cross-sectional view of the third copper layer and the fourth copper layer after being patterned to form the second circuit layer and the third circuit layer respectively.

[0030] Figure 13 For Figure 12 The diagram shows a cross section of a laminate formed after a second solder mask layer is provided on the surface of the second circuit layer.

[0031] Figure 14 To remove Figure 13 The schematic cross-sectional view of a portion of the laminated panel after windowing is formed.

[0032] Figure 15 To removeFigure 14 A cross-sectional view of a fifth intermediate body after exposing a portion of the first circuit layer to reveal the gold finger pattern.

[0033] Figure 16 To Figure 15 A partial top view of the fifth intermediate body.

[0034] Figure 17 To Figure 15 A cross-sectional view of a sixth intermediate body after disposing an electroless nickel immersion gold layer on the surface of the gold finger pattern to form a gold finger.

[0035] Figure 18 To Figure 17 A partial top view of the sixth intermediate body.

[0036] Figure 19 To Figure 17 A cross-sectional view of a circuit board structure with a stepped half-embedded gold finger obtained by removing a portion of the sixth intermediate body.

[0037] Figure 20 To Figure 19 A partial top view of the circuit board structure with a stepped half-embedded gold finger.

[0038] Explanation of main element symbols

[0039] Circuit board structure 1000

[0040] Copper-clad substrate 10

[0041] Substrate layer 11

[0042] First metal layer 12

[0043] Second metal layer 13

[0044] Groove 14

[0045] Groove area R

[0046] First copper layer 20

[0047] Second copper layer 22

[0048] Gold finger pattern 24

[0049] First intermediate body 25

[0050] First circuit layer 26

[0051] Conductive wire precursor 241

[0052] Second intermediate body 28

[0053] First solder mask layer 30

[0054] first opening 32

[0055] third intermediate body 33

[0056] solder resist buffer zone 35

[0057] flowable prepreg 40

[0058] second opening 42

[0059] double-sided copper clad plate 50

[0060] insulating layer 51

[0061] third metal layer 52

[0062] fourth metal layer 53

[0063] fourth intermediate body 55

[0064] through hole 60

[0065] third copper layer 61

[0066] hole wall copper layer 62

[0067] fourth copper layer 63

[0068] conductive hole 65

[0069] second circuit layer 70

[0070] third circuit layer 72

[0071] second solder resist layer 80

[0072] hole wall solder resist layer 82

[0073] third solder resist layer 84

[0074] pressing plate 85

[0075] third opening 86

[0076] window 87

[0077] wire 88

[0078] fifth intermediate body 88a

[0079] electroless nickel immersion gold layer 90

[0080] gold finger 100

[0081] sixth intermediate body 101

[0082] stepped groove 102

[0083] The following detailed description will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0084] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0085] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "top", "side", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0086] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0087] In order to further illustrate the technical means and effects adopted by this application to achieve the intended purpose, the following detailed description of this application is made in conjunction with the accompanying drawings and preferred implementation methods.

[0088] See also Figures 1 to 20 An embodiment of the present application provides a method for manufacturing a circuit board structure 1000 having stepped semi-embedded gold fingers, comprising the following steps:

[0089] Step S1: Please refer to Figure 1 and Figure 2 , a copper clad substrate 10 is provided, wherein one surface of the copper clad substrate 10 is concavely formed with a plurality of grooves 14.

[0090] The copper clad substrate 10 includes a base layer 11 and a first metal layer 12 and a second metal layer 13 arranged on opposite sides of the base layer 11. A plurality of grooves 14 are provided through part of the base layer 11 to form a groove area R. The first metal layer 12 is provided on a portion of the base layer 11 except the groove area R.

[0091] Specifically, the recessed area R can be formed by first etching the first metal layer 12 to expose part of the substrate layer 11, and then removing the exposed part of the substrate layer 11 in the recessed area R by laser etching or dry etching process, to form a plurality of recesses 14.

[0092] The shape of the recesses 14 is consistent with the shape of the subsequent gold finger 100 (see Figure 20 ). In this embodiment, the plurality of recesses 14 are arranged in parallel and spaced apart.

[0093] The material of the substrate layer 11 can be selected from one of the resins such as epoxy resin, ABF resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). The materials of the first metal layer 12 and the second metal layer 13 are copper.

[0094] Step S2: Please refer to Figure 3 and Figure 4 , a first copper layer 20 and a second copper layer 22 are respectively formed on opposite sides of the copper-clad substrate 10, the first copper layer 20 partially fills into the recesses 14 to form a gold finger pattern 24, and a first intermediate body 25 is obtained.

[0095] Specifically, the copper-clad substrate 10 is subjected to whole-plate electroplating to form a first copper layer 20 on the surface of the first metal layer 12 and the recessed area R, a second copper layer 22 on the surface of the second metal layer 13, and the gold finger pattern 24 by electroplating filling the recesses 14.

[0096] It can be understood that the first copper layer 20 partially covers the first metal layer 12 and partially covers the substrate layer 11.

[0097] Step S3: Please refer to Figure 5 and Figure 6 , the first copper layer 20 and the corresponding first metal layer 12 are patterned to form a first circuit layer 26, and a second intermediate body 28 is obtained.

[0098] Specifically, the first circuit layer 26 can be formed by attaching a photosensitive dry film to the surface of the first copper layer 20, and then exposing, developing, and etching.

[0099] In step S3, the first copper layer 20 and the corresponding first metal layer 12 are patterned to form a first circuit layer 26, and a second intermediate body 28 is obtained.

[0100] The first copper layer 20 and the first metal layer 12 form a plurality of wire precursors 241.

[0101] The wire precursors 241 are formed on one side of the gold finger pattern 24, and each wire precursor 241 corresponds to one gold finger pattern 24.

[0102] Step S4: please refer to Figure 7 and Figure 8 , a first anti-solder layer 30 is arranged on the surface of the first circuit layer 26 to obtain a third intermediate body 33.

[0103] The first anti-solder layer 30 has a first opening 32, the size of the first opening 32 is greater than the size of the recessed area R, and the gold finger pattern 24 and the wire precursor 241 and part of the first copper layer 20 are exposed by the first opening 32.

[0104] Step S5: please refer to Figure 13 and Figure 14 , the no-flow prepreg sheet 40 and the press plate 85 are sequentially pressed on the surface of the first anti-solder layer 30 away from the first circuit layer 26, the no-flow prepreg sheet 40 is provided with a second opening 42 in advance, the second opening 42 is arranged corresponding to the first opening 32, part of the press plate 85 is removed to form a window 87 corresponding to the second opening 42, and the gold finger pattern 24 is exposed by the window 87.

[0105] The third opening 86 is formed after part of the press plate 85 is removed, and the third opening 86 and the second opening 42 communicate to form the window 87.

[0106] In this embodiment, the size of the third opening 86 is the same as that of the second opening 42, that is, the direct projection of the second opening 42 on the first anti-solder layer 30 is completely coincident with the direct projection of the third opening 86 on the first anti-solder layer 30.

[0107] Specifically, step S5 includes:

[0108] Step S51: please refer to Figure 9 , the no-flow prepreg sheet 40 and the double-sided copper-clad plate 50 are sequentially pressed on the surface of the first anti-solder layer 30 away from the first circuit layer 26 to obtain a fourth intermediate body 55.

[0109] The double-sided copper-clad plate 50 includes an insulating layer 51 and third and fourth metal layers 52 and 53 arranged on opposite sides of the insulating layer 51, and the fourth metal layer 53 is connected to the no-flow prepreg sheet 40.

[0110] The width W2 of the second opening 42 is greater than the width W1 of the first opening 32, and the orthographic projection of the second opening 42 on the first anti-welding layer 30 covers the first opening 32, thereby forming an anti-welding buffer zone 35 on each side of the gold finger pattern 24. By arranging the flow-free prepreg 40 and forming the anti-welding buffer zone 35, the gold finger pattern 24 can be prevented from being contaminated during pressing.

[0111] Step S52: please refer to Figure 10 At least one through hole 60 is formed through the fourth intermediate body 55.

[0112] Specifically, the through hole 60 with a vertical structure can be processed by mechanical drilling.

[0113] Step S53: please refer to Figure 11 A third copper layer 61 is formed on the surface of the third metal layer 52, a hole wall copper layer 62 is formed on the hole wall of the through hole 60, and a fourth copper layer 63 is formed on the surface of the second metal layer 13.

[0114] Specifically, the third copper layer 61, the hole wall copper layer 62 and the fourth copper layer 63 are sequentially formed by whole-board electroplating. After the hole wall copper layer 62 is formed in the through hole 60, a conductive hole 65 is formed.

[0115] Step S54: please refer to Figure 12 The third copper layer 61 and the corresponding third metal layer 52 are patterned to form a second circuit layer 70, and the fourth copper layer 63 and the corresponding second metal layer 13 are patterned to form a third circuit layer 72.

[0116] Specifically, the second circuit layer 70 and the third circuit layer 72 can be formed by respectively pasting a photosensitive dry film on the surface of the third copper layer 61 and the fourth copper layer 63, and then exposing, developing and etching.

[0117] Step S55: please refer to Figure 13 A second anti-welding layer 80 is arranged on the surface of the second circuit layer 70, a hole wall anti-welding layer 82 is arranged on the surface of the hole wall copper layer 62, and a third anti-welding layer 84 is arranged on the surface of the third circuit layer 72.

[0118] The second anti-welding layer 80, the hole wall anti-welding layer 82 and the third anti-welding layer 84 are sequentially connected. The substrate layer 11, the fourth metal layer 53, the second circuit layer 70 and the second anti-welding layer 80 together form a pressing plate 85.

[0119] Step S6: please refer to Figure 15 and Figure 16Corresponding to the first opening 32, the exposed part of the first copper layer 20 is removed to expose the gold finger pattern 24 and part of the substrate layer 11, obtaining a fifth intermediate body 88a.

[0120] Specifically, the exposed part of the first circuit layer 26 is removed by using a copper reduction process with chemical solution. In this process, the copper layer around each gold finger pattern 24 is removed.

[0121] Step S6 further includes: corresponding to the wire precursor 241, removing part of the first copper layer 20 while retaining part of the first metal layer 12, thereby forming a wire 88.

[0122] Step S7: please refer to Figure 17 and Figure 18 , a nickel gold layer 90 is arranged on the surface of the gold finger pattern 24 to form a gold finger 100, obtaining a sixth intermediate body 101.

[0123] Specifically, the surface of the gold finger pattern 24 is provided with a nickel gold layer 90 to form a gold finger 100 by using a nickel gold plating process. In this process, the wire 88 serves as an auxiliary process wire for connecting external plating equipment to provide current to the gold finger pattern 24 to complete the nickel and gold plating process.

[0124] In this process, the surface of the gold finger pattern 24 away from the substrate layer 11 is approximately flush with the surface of the first metal layer 12 away from the substrate layer 11, and the surface of the nickel gold layer 90 away from the gold finger pattern 24 is approximately flush with the surface of the first copper layer 20 away from the first metal layer 12.

[0125] Step S8: please refer to Figure 19 and Figure 20 , part of the sixth intermediate body 101 is removed on the side of the gold finger 100 where the wire 88 is arranged, obtaining a circuit board structure 1000 with a stepped semi-embedded gold finger.

[0126] Specifically, part of the sixth intermediate body 101 is cut off by using a CNC process. In this process, the wire 88 and part of the structure corresponding to the wire 88 are cut off at the same time to cut off the connection between the gold finger 100 and external equipment, and restore the connection relationship between the internal circuits of the circuit board structure 1000.

[0127] In this process, after part of the sixth intermediate body 101 is removed, a stepped groove 102 is formed at the window 87, which can be used for external equipment to plug into the gold finger 100.

[0128] Compared with the prior art, the manufacturing method of the circuit board structure 1000 with a stepped semi-embedded gold finger provided in the present application has the following advantages:

[0129] (1) By pre-opening the second opening 42 in the flow-free prepreg 40, only the pressed part of the pressing plate 85 needs to be removed to continue processing the exposed gold finger pattern 24, without the need for high-precision depth-drawing operations, and the process is simple.

[0130] (2) By exposing the gold finger pattern 24 through the copper reduction process, and then setting the electro-nickel gold layer 90 to form the gold finger 100, it is not necessary to paste a protective tape on the surface of the gold finger 100, thereby saving the processes of pasting, pressing, and tearing off the tape, and there will be no residual glue stains on the gold finger 100, which can ensure the quality.

[0131] (3) By using the flow-free prepreg 40, and forming the solder mask buffer zone 35 corresponding to the area of the first solder mask layer 30 close to the gold finger pattern 24, it can be ensured that there is no flow glue pollution during pressing.

[0132] (4) By semi-embedding the gold finger 100 in the substrate layer 11, the embedding adhesion can be increased, and the risk of separation caused by multiple plugging and unplugging can be reduced.

[0133] Please refer to Figure 19 and Figure 20 , the embodiment of the present application also provides a circuit board structure 1000 with a stepped semi-embedded gold finger, which is made by the above manufacturing method, comprising a substrate layer 11, a gold finger 100, a first circuit layer 26, a first solder mask layer 30, a third circuit layer 72, a flow-free prepreg 40, and a pressing plate 85. The gold finger 100 comprises a gold finger pattern 24 embedded in the substrate layer 11 and an electro-nickel gold layer 90 arranged on the surface of the gold finger pattern 24. The first circuit layer 26 and the third circuit layer 72 are arranged on opposite sides of the substrate layer 11. The first solder mask layer 30, the flow-free prepreg 40, and the pressing plate 85 are sequentially stacked on the surface of the first circuit layer 26.

[0134] Among them, the first solder mask layer 30, the third circuit layer 72, the flow-free prepreg 40, and the pressing plate 85 are arranged away from the gold finger 100. The surface of the electro-nickel gold layer 90 facing away from the gold finger pattern 24 is substantially flush with the surface of the first circuit layer 26 facing away from the substrate layer 11. The side of the flow-free prepreg 40 and the pressing plate 85 facing the gold finger 100 forms a stepped groove 102 with the surface of the substrate layer 11. The gold finger 100 and part of the substrate layer 11 are exposed by the stepped groove 102.

[0135] The flowless prepreg 40 and the laminated board 85 are substantially flush with the end surface of the stepped groove 102, and the first solder mask layer 30 partially extends out of the end surface to form a solder mask buffer zone 35. The first circuit layer 26 includes a first metal layer 12 and a first copper layer 20 stacked in sequence, the first metal layer 12 is connected to the substrate layer 11, the surface of the first metal layer 12 is substantially flush with the surface of the gold finger pattern 24, and the surface of the first copper layer 20 is substantially flush with the surface of the electro-nickel-gold layer 90.

[0136] The laminated board 85 includes a third metal layer 52, an insulating layer 51, a second circuit layer 70, and a second solder mask layer 80 stacked in sequence. The circuit board structure 1000 is further provided with a conductive hole 65, the conductive hole 65 includes a through hole 60 penetrating through the circuit board structure 1000 and a hole wall copper layer 62 provided on the hole wall of the through hole 60, and the surface of the hole wall copper layer 62 is further provided with a hole wall solder mask layer 82. The surface of the third circuit layer 72 away from the substrate layer 11 is further provided with a third solder mask layer 84.

[0137] The above description is merely one optimized specific embodiment of the present application, but in actual application process, it cannot be limited to this embodiment.

Claims

1. A method for manufacturing a circuit board structure with a stepped semi-embedded gold finger, characterized in that: The method comprises the following steps: providing a copper-clad substrate, the copper-clad substrate comprising a substrate layer and a first metal layer arranged on the surface of the substrate layer, a plurality of grooves being arranged through the substrate layer to form a grooved area, the first metal layer being arranged on the substrate layer except for the grooved area; forming a first copper layer on the surface of the first metal layer and the grooved area, the first copper layer being partially filled into the grooves to form a gold finger pattern; removing part of the first metal layer and the corresponding first copper layer to form a plurality of wire precursors, each of the wire precursors being connected to a gold finger pattern; arranging a first solder mask layer on the surface of the first copper layer, the first solder mask layer having a first opening, the gold finger pattern being exposed by the first opening; stacking a flow-free prepreg and a press plate on the surface of the first solder mask layer, the flow-free prepreg having a second opening corresponding to the first opening; removing part of the press plate corresponding to the second opening to form a window, the gold finger pattern being exposed by the window; removing part of the first copper layer in the grooved area corresponding to the first opening to expose the gold finger pattern; removing part of the first copper layer included in the wire precursor to expose part of the first metal layer and form a wire; arranging a nickel-gold layer on the surface of the gold finger pattern to form a gold finger, removing the wire and part of the structure located on the side of the gold finger where the wire is arranged, and forming a stepped slot at the window to obtain a circuit board structure having a stepped semi-embedded gold finger.

2. The method of claim 1, wherein The width of the second opening is greater than the width of the first opening, and the orthographic projection of the second opening on the first solder mask layer covers the first opening to form a solder mask buffer layer on both sides of the gold finger pattern.

3. The method of claim 1, wherein After the step of "forming a first copper layer on the surface of the first metal layer and the grooved area", the method further comprises: patterning part of the first copper layer and the corresponding first metal layer to form a first circuit layer.

4. The method of claim 1, wherein The copper-clad substrate further comprises a second metal layer arranged on the side of the substrate layer away from the first metal layer. The step of "forming a first copper layer on the surface of the first metal layer and the grooved area" further comprises: forming a second copper layer on the surface of the second metal layer; The step of "stacking a flow-free prepreg and a press plate on the surface of the first solder mask layer" comprises: stacking a flow-free prepreg and a double-sided copper-clad plate on the surface of the first solder mask layer, the double-sided copper-clad plate comprising an insulating layer and third and fourth metal layers arranged on opposite sides of the insulating layer, the fourth metal layer being connected to the flow-free prepreg to obtain an intermediate body; forming a through hole through the intermediate body; arranging a third copper layer on the surface of the third metal layer and a fourth copper layer on the surface of the second copper layer to form a hole wall copper layer on the hole wall of the through hole to form a conductive hole; patterning the third metal layer and the corresponding third copper layer to form a second circuit layer, and patterning the fourth copper layer, the corresponding second copper layer, and the second metal layer to form a third circuit layer. A second anti-soldering layer is formed on the surface of the second circuit layer, a third anti-soldering layer is formed on the surface of the third circuit layer, and a hole-wall anti-soldering layer is formed on the surface of the hole-wall copper layer; the second anti-soldering layer, the second circuit layer, the insulating layer, and the fourth metal layer together form the pressboard.

5. A circuit board structure with stepped semi-embedded gold fingers manufactured by the method for manufacturing a circuit board structure with stepped semi-embedded gold fingers according to any one of claims 1 to 4, characterized in that: The printed circuit board comprises a substrate layer, a gold finger, a first circuit layer, a first anti-soldering layer, a flow-gel-free prepreg, and a pressboard. The gold finger comprises a gold finger pattern embedded in the substrate layer and an electro-nickel-gold layer arranged on the surface of the gold finger pattern and protruding from the surface of the substrate layer. The first circuit layer, the first anti-soldering layer, the flow-gel-free prepreg, and the pressboard are sequentially arranged on the surface of the substrate layer provided with the gold finger and avoid the gold finger. The gold finger is electrically connected to the first circuit layer.

6. The circuit board structure of claim 5, wherein, The flow-gel-free prepreg and the pressboard on the side facing the gold finger form a stepped groove with the surface of the substrate layer. The gold finger and part of the substrate layer are exposed by the stepped groove.

7. The circuit board structure of claim 5, wherein, The flow-gel-free prepreg and the pressboard on the side facing the stepped groove are flush with the end surface. The first anti-soldering layer partially extends out of the end surface to form an anti-soldering buffer zone.

8. The circuit board structure of claim 5, wherein, The first circuit layer comprises a first metal layer and a first copper layer stacked together. The first metal layer is connected to the substrate layer. The gold finger pattern is flush with the surface of the first metal layer. The electro-nickel-gold layer is flush with the surface of the first copper layer.

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