A high-reliability through-hole copper plating structure and manufacturing method thereof

Abstract

The invention discloses a high-reliability through-hole copper-plated structure and a manufacturing method thereof. The through-hole copper-plated structure comprises a circuit board, the circuit board is provided with a through-hole, two board surfaces of the circuit board are respectively provided with base copper, the hole wall of the through-hole is provided with hole copper, and a mortise and tenon structure for strengthening the connection is provided between the hole copper and the base copper. The invention can improve the connection strength between the hole copper and the base copper, and improve the production quality of the PCB board.

Description

Technical Field

[0001] The invention belongs to the technical field of PCB board manufacturing, and relates to a high-reliability through-hole copper-plated structure and a manufacturing method thereof. Background Art

[0002] With the development of science and technology and the improvement of people's lives, people have higher and higher requirements for the intelligence of electronic devices, making the design of PCB boards, the cornerstone of electronic devices, more and more complex, smaller and smaller, and more and more densely populated. Conventional methods for making fine lines include copper reduction (thinning the surface copper thickness to facilitate etching of lines), vacuum etching (enhancing etching capabilities), hole plating (only plating holes without plating the board surface to reduce the surface copper thickness), etc.

[0003] However, the above technologies all have different limitations. The copper reduction method or vacuum etching method cannot overcome the changes in etching accuracy caused by uneven surface copper thickness, resulting in extremely poor yield when making dense and fine circuits. The hole electroplating method only plates holes and does not increase the surface copper thickness. It can overcome the problem of circuit etching uniformity, but there is a problem of weak connection between hole copper and base copper, which is very easy to break when electronic products are subjected to cold and hot shocks. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a high-reliability through-hole copper plating structure and a manufacturing method thereof, which can improve the connection strength between the hole copper and the base copper and improve the production quality of the PCB board.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] A high-reliability through-hole copper-plated structure comprises a circuit board, wherein the circuit board is provided with a through-hole, base copper is respectively provided on two board surfaces of the circuit board, hole copper is provided on the hole wall of the through-hole, and a mortise and tenon structure for strengthening the connection is provided between the hole copper and the base copper.

[0007] Optionally, the mortise and tenon structure includes a connecting protrusion and a connecting groove for installing the connecting protrusion, the connecting protrusion is arranged on the hole copper at both ends of the through hole, and the connecting groove is arranged on the base copper at both ends of the through hole.

[0008] A method for manufacturing a high-reliability through-hole copper-plated structure comprises the following steps:

[0009] Pressing a plurality of core boards together to obtain a circuit board;

[0010] Cover the two surfaces of the circuit board with dry film;

[0011] Expose and develop the circuit board covered with the dry film once, so that the dry film at the position where the window needs to be opened on the circuit board is developed away to expose the base copper;

[0012] Etching and reducing the exposed base copper;

[0013] Remove the dry film on both sides of the circuit board;

[0014] Drilling the base copper at the etched copper reduction location to obtain a through hole;

[0015] Performing metal coating on the hole wall of the through hole;

[0016] Cover the two surfaces of the circuit board with the dry film again;

[0017] The circuit board covered with the dry film is exposed and developed twice, so that the dry film at the position where the window needs to be opened on the circuit board is developed away, exposing the base copper and through holes at the etching copper reduction position;

[0018] Electroplating copper on the through hole wall after metal plating to obtain hole copper, so that the electroplated copper at both ends of the through hole is connected to the base copper at the etching copper reduction location;

[0019] Remove the dry film on both sides of the circuit board again;

[0020] Circuits are etched out on the circuit board after the dry film is removed again.

[0021] Optionally, also include:

[0022] After removing the dry film on both sides of the circuit board again, the electroplated copper is leveled so that the electroplated copper at both ends of the through hole is level with the base copper surface.

[0023] Optionally, the protrusions on the electroplated copper surface at both ends of the through hole are lightly brushed with a ceramic brush to smooth the electroplated copper.

[0024] Optionally, the area of ​​the base copper exposed by one exposure and development is larger than the cross-sectional area of ​​the through hole.

[0025] Optionally, the hole wall of the through hole is metal-plated by polymer conductive film, sputtering or chemical copper deposition.

[0026] Optionally, the area of ​​the dry film removed by the first exposure is greater than the area of ​​the dry film removed by the second exposure.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a high-reliability through-hole copper plating structure and a manufacturing method thereof, wherein a mortise and tenon structure is provided between the through-hole copper and the base copper, and the mortise and tenon structure can increase the contact surface between the through-hole copper and the base copper at the through-hole opening, thereby enhancing the connection strength between the through-hole copper and the base copper, and preventing the through-hole copper and the base copper from being broken;

[0029] The mortise and tenon structure can be completed through two exposure and development steps, etching of base copper and electroplating of copper in through holes. The whole process is simple and convenient, without the need for thickening of electroplated copper, which greatly improves the circuit accuracy and uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is a flow chart of a high-reliability through-hole copper plating structure and a manufacturing method thereof of the present invention;

[0031] Figure 2 Shown is a cross-sectional view of a circuit board in the first step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0032] Figure 3 It is a cross-sectional view of a circuit board in the second step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0033] Figure 4 It is a cross-sectional view of a circuit board in the third step of the high-reliability through-hole copper plating structure and the manufacturing method thereof according to the present invention;

[0034] Figure 5 The figure shows a cross-sectional view of a circuit board in the fourth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0035] Figure 6 It is a cross-sectional view of the circuit board of the fifth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0036] Figure 7 Shown is a cross-sectional view of a circuit board in the sixth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0037] Figure 8 The figure shows a cross-sectional view of a circuit board in the seventh step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0038] Fig. 9 It is a cross-sectional view of the circuit board of the eighth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0039] Fig.10 It is a cross-sectional view of the circuit board of the ninth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0040] Fig.11 It is a cross-sectional view of the circuit board of the tenth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0041] Fig.12 Shown is a cross-sectional view of a circuit board in the eleventh step of the high-reliability through-hole copper plating structure and the manufacturing method thereof of the present invention;

[0042] Fig.13 It is a cross-sectional view of a circuit board in the twelfth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof according to the present invention;

[0043] Fig.14Shown is a cross-sectional view of a circuit board of the thirteenth step of the high-reliability through-hole copper plating structure and the manufacturing method thereof according to the present invention.

[0044] In the figure: 1, circuit board; 11, core board; 2, through hole; 3, base copper; 4, hole copper; 5, connection protrusion; 6, connection groove; 7, dry film. Implementation

[0045] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0046] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0047] For the purpose of this specification and the appended claims, unless otherwise stated, all numbers expressing amounts, percentages or ratios and other numerical values ​​used in this specification and the appended claims are understood to be modified in all cases by the term "about". In addition, all ranges disclosed herein are inclusive and independently combinable. Embodiment 1

[0048] like Figure 2 As shown, a high-reliability through-hole copper-plated structure includes a circuit board 1, a through-hole 2 is provided on the circuit board 1, base copper 3 is provided on two sides of the circuit board, hole copper 4 is provided on the hole wall of the through-hole 2, and a mortise and tenon structure for strengthening the connection is provided between the hole copper 4 and the base copper 3.

[0049] The mortise and tenon structure includes a connecting protrusion 5 and a connecting groove 6 for installing the connecting protrusion 5. The connecting protrusion 5 is arranged on the hole copper 4 at both ends of the through hole 2, and the connecting groove 6 is arranged on the base copper 3 at both ends of the through hole 2. The connecting protrusion 5 is connected to the connecting groove 6. Embodiment 2

[0050] like Figure 1 and Figure 2 As shown, based on a high-reliability through-hole copper plating structure provided in Embodiment 1, this embodiment provides a method for manufacturing a high-reliability through-hole copper plating structure, comprising the following steps:

[0051] S1, pressing a plurality of core boards 11 to obtain a circuit board 1;

[0052] S2, covering the two surfaces of the circuit board 1 with a dry film 7;

[0053] S3, performing exposure and development on the circuit board 1 covered with the dry film 7, so that the dry film at the position where the window is required on the circuit board 1 is developed away, exposing the base copper 3;

[0054] S4, etching and reducing the exposed base copper 3 to obtain a connection groove 6;

[0055] S5, removing the dry film 7 on both sides of the circuit board 1;

[0056] S6, drilling the bottom of the connecting groove 6 to obtain a through hole 2;

[0057] S7, performing copper metal plating on the hole wall of the through hole 2 by polymer conductive film, sputtering or chemical copper deposition;

[0058] S8, covering the two surfaces of the circuit board 1 with the dry film 7 again;

[0059] S9, performing secondary exposure and development on the circuit board covered with the dry film 7, so that the dry film 7 at the position where the window needs to be opened on the circuit board 1 is developed away, exposing the connection groove 6 and the through hole 2;

[0060] S10, electroplating copper on the hole wall of the through hole 2 after metal plating to obtain hole copper 4, so that the connecting protrusions 5 at both ends of the through hole 2 are connected to the connecting grooves 6;

[0061] S11, removing the dry film 7 on both sides of the circuit board 1 again;

[0062] S12, etching a circuit on the circuit board 1 from which the dry film 7 is removed again.

[0063] The circular diameter of the base copper 3 exposed by one exposure and development is 0.4 mm to 2 mm larger than the hole diameter of the through hole 2.

[0064] The diameter of the circle of the dry film 7 removed by the first exposure and development is 0.05 mm to 0.1 mm larger than the diameter of the circle of the dry film 7 removed by the second exposure and development. Embodiment 3

[0065] like Figure 1 and Figure 2 As shown, based on a high-reliability through-hole copper plating structure provided in Embodiment 1, this embodiment provides a method for manufacturing a high-reliability through-hole copper plating structure, comprising the following steps:

[0066] S1, pressing a plurality of core boards 11 to obtain a circuit board 1;

[0067] S2, covering the two surfaces of the circuit board 1 with a dry film 7;

[0068] S3, performing exposure and development on the circuit board 1 covered with the dry film 7, so that the dry film at the position where the window is required on the circuit board 1 is developed away, exposing the base copper 3;

[0069] S4, etching and reducing the exposed base copper 3 to obtain a connection groove 6;

[0070] S5, removing the dry film 7 on both sides of the circuit board 1;

[0071] S6, drilling the bottom of the connecting groove 6 to obtain a through hole 2;

[0072] S7, performing copper metal plating on the hole wall of the through hole 2 by polymer conductive film, sputtering or chemical copper deposition;

[0073] S8, covering the two surfaces of the circuit board 1 with the dry film 7 again;

[0074] S9, performing secondary exposure and development on the circuit board covered with the dry film 7, so that the dry film 7 at the position where the window needs to be opened on the circuit board 1 is developed away, exposing the connection groove 6 and the through hole 2;

[0075] S10, electroplating copper on the hole wall of the through hole 2 after metal plating to obtain hole copper 4, so that the connecting protrusions 5 at both ends of the through hole 2 are connected to the connecting grooves 6;

[0076] S11, removing the dry film 7 on both sides of the circuit board 1 again;

[0077] S12, after removing the dry film 7 on both sides of the circuit board 1 again, the protrusions on the surface of the connecting protrusions 5 at both ends of the through hole 2 are lightly brushed with a ceramic brush to flatten the connecting protrusions 5 so that the connecting protrusions 5 at both ends of the through hole 2 are flat with the surface of the base copper 3;

[0078] S13, etching a circuit on the circuit board 1 from which the dry film 7 is removed again.

[0079] The circular diameter of the base copper 3 exposed by one exposure and development is 0.4 mm to 2 mm larger than the hole diameter of the through hole 2.

[0080] The diameter of the circle of the dry film 7 removed by the first exposure and development is 0.05 mm to 0.1 mm larger than the diameter of the circle of the dry film 7 removed by the second exposure and development.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for manufacturing a high-reliability through-hole copper-plated structure, the through-hole copper-plated structure comprising a circuit board, the circuit board is provided with a through hole, two board surfaces of the circuit board are respectively provided with base copper, and the hole wall of the through hole is provided with hole copper, characterized in that: A mortise and tenon structure for strengthening the connection is provided between the hole copper and the base copper; The manufacturing method of the through-hole copper-plated structure includes pressing a plurality of core boards together to obtain a circuit board; covering two surfaces of the circuit board with a dry film; Expose and develop the circuit board covered with the dry film once, so that the dry film at the position where the window needs to be opened on the circuit board is developed away to expose the base copper; Etching and reducing the exposed base copper; Remove the dry film on both sides of the circuit board; Drilling the base copper at the etched copper reduction location to obtain a through hole; Performing metal coating on the hole wall of the through hole; Cover the two surfaces of the circuit board with the dry film again; The circuit board covered with the dry film is exposed and developed twice, so that the dry film at the position where the window is required on the circuit board is developed away, exposing the base copper and through hole at the etching copper reduction position; Electroplating copper on the through hole wall after metal plating to obtain hole copper, so that the electroplated copper at both ends of the through hole is connected to the base copper at the etching copper reduction location; Remove the dry film on both sides of the circuit board again; A circuit is etched on the circuit board from which the dry film is removed again; the area of ​​the dry film removed by the first exposure is larger than the area of ​​the dry film removed by the second exposure; after the dry film on both sides of the circuit board is removed again, the electroplated copper is leveled so that the electroplated copper at both ends of the through hole is leveled with the base copper surface.

2. The method for manufacturing a high-reliability through-hole copper-plated structure according to claim 1, characterized in that: The mortise and tenon structure comprises a connecting protrusion and a connecting groove for installing the connecting protrusion, the connecting protrusion is arranged on the hole copper at both ends of the through hole, and the connecting groove is arranged on the base copper at both ends of the through hole.

3. The method for manufacturing a high-reliability through-hole copper-plated structure according to claim 1, characterized in that: The protrusions on the electroplated copper surface at both ends of the through hole are lightly brushed with a ceramic brush to smooth the electroplated copper.

4. The method for manufacturing a high-reliability through-hole copper-plated structure according to claim 1, characterized in that: The area of ​​the base copper exposed by one exposure and development is larger than the cross-sectional area of ​​the through hole.

5. The method for manufacturing a high-reliability through-hole copper-plated structure according to claim 1, wherein: The hole wall of the through hole is metal-plated by polymer conductive film, sputtering or chemical copper deposition.

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