Process method for improving warping of PCB after hot air leveling

Abstract

The invention discloses a process method for improving warping of a PCB (Printed Circuit Board) after hot air leveling, relates to the technical field of PCB processing processes, and can avoid warping of one side with a circuit and improve the quality level of a product. The invention discloses a process method for improving warping of a PCB after hot air leveling. The process method comprises the following steps of alkaline etching, wherein a mother board is etched, and patterns on outer-layer copper plating and outer-layer base copper are completed; solder mask: manufacturing a solder mask layer on the surface of the mother board; hot air leveling, wherein hot air leveling is conducted on the mother board; a dry film is attached to one side of the mother board; tin removing: removing a tin layer generated by hot air leveling and carrying out surface treatment; carrying out surface treatment on the mother board; and film stripping: stripping the dry film pasted in the dry film stripping step. After an outer-layer circuit is protected through solder mask, hot air is fed into the two faces of the circuit board for leveling at the same time, after hot air leveling, a dry film is used for protecting one face, needing to be kept for hot air leveling, of a tin layer, the tin layer on the other face is removed, and then other surfaces are manufactured, so that warping is improved.

Description

Technical Field

[0001] The invention relates to the technical field of PCB processing technology, and in particular to a method for improving the warping of a PCB after hot air leveling. Background Art

[0002] When hot air leveling is performed on existing PCBs (printed circuit boards), the B side without circuits is first sealed with a protective film and then hot air leveling is performed. After hot air leveling, the heat dissipation on the B side is slow, while the heat dissipation on the A side with circuits is fast, causing the product to bend toward the side with faster heat dissipation, ultimately resulting in large product warping. Summary of the invention

[0003] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for improving the warping process of PCB after hot air leveling, which can avoid warping on the side with circuits and improve the quality level of the product.

[0004] The present invention provides a process method for improving the warping of a PCB after hot air leveling, comprising the following steps:

[0005] Alkaline etching: Etching the motherboard to complete the pattern on the outer copper plating and the outer base copper;

[0006] Solder mask: Make a solder mask on the surface of the motherboard;

[0007] Hot air leveling: hot air leveling the motherboard;

[0008] Dry film: Apply dry film on one side of the motherboard;

[0009] Tinning: remove the tin layer produced by hot air leveling;

[0010] Surface treatment: Surface treatment of the motherboard;

[0011] Film removal: Remove the dry film applied in the dry film step.

[0012] A process method for improving PCB warping after hot air leveling according to an embodiment of the present invention has at least the following beneficial effects: after the outer layer circuit is protected by solder mask, hot air leveling is performed on both sides of the circuit board at the same time, and after hot air leveling, dry film is used to protect the side of the tin layer that needs to be retained for hot air leveling, and the tin layer on the other side is removed, and then other surfaces are manufactured, thereby achieving improvement in warping.

[0013] According to the method for improving the warpage of PCB after hot air leveling of the present invention, before the alkaline etching step, the following steps are also included:

[0014] Sub-board etching: Etching the sub-board to complete the sub-board circuit;

[0015] Lamination: Laminating the daughter boards to form the mother board;

[0016] Drilling: Drill holes on the motherboard;

[0017] Copper plating: Copper plating is performed on the drilled holes to complete the hole metallization.

[0018] According to a process method for improving PCB warping after hot air leveling described in the present invention, in the alkaline etching step, the outer layer circuit is manufactured by external light imaging, copper tin plating, and alkaline etching.

[0019] According to a method for improving PCB warping after hot air leveling described in the present invention, in the soldering step, soldering protection is performed on the outer layer circuit side of the motherboard, and then hot air leveling is performed on the outer layer circuit side and the non-circuit side of the PCB at the same time.

[0020] According to a process method for improving PCB warping after hot air leveling described in the present invention, in the dry film step, a layer of dry film is attached to one side of the outer layer circuit of the motherboard.

[0021] According to a process method for improving PCB warping after hot air leveling described in the present invention, in the film stripping step, the dry film attached to one side of the outer layer circuit of the motherboard in the dry film stripping step is removed.

[0022] According to a process method for improving PCB warping after hot air leveling described in the present invention, the tin layer on the non-circuit side of the PCB is removed in the tin stripping step, and then the non-circuit side of the motherboard is surface treated in the surface treatment step.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0025] Figure 1 This is a schematic diagram of the structure of a preferred embodiment of the present invention after alkaline etching is completed;

[0026] Figure 2 This is a schematic diagram of the structure after solder mask is completed in a preferred embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of a preferred embodiment of the present invention after hot air leveling is completed;

[0028] Figure 4 This is a schematic diagram of the structure after the drying step is completed in a preferred embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of a preferred embodiment of the present invention after the tin stripping step is completed;

[0030] Figure 6 This is a schematic diagram of the structure after the surface treatment step is completed in a preferred embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure after the film stripping step is completed in a preferred embodiment of the present invention;

[0032] Figure 8 The process flow chart of the preferred embodiment of the present invention.

[0033] Reference numerals: substrate 10 , inner layer circuit 20 , prepreg 30 , outer layer base copper 40 , outer layer copper plating 50 , solder mask 60 , tin layer 70 , dry film 80 , other surface treatment layers 90 . DETAILED DESCRIPTION

[0034] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0037] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0038] Reference Figures 1 to 8 A method for improving the warping of PCB after hot air leveling includes the following steps:

[0039] Alkaline etching: Etching the motherboard to complete the pattern on the outer copper plating and the outer base copper;

[0040] Solder mask: Make a solder mask on the surface of the motherboard;

[0041] Hot air leveling: hot air leveling the motherboard;

[0042] Dry film: Apply dry film on one side of the motherboard;

[0043] Tinning: remove the tin layer produced by hot air leveling;

[0044] Surface treatment: Surface treatment of the motherboard;

[0045] Film removal: Remove the dry film applied in the dry film step.

[0046] The present invention protects the outer layer circuit with solder mask and then performs hot air leveling on both sides of the circuit board. After hot air leveling, a dry film 80 is used to protect the side of the tin layer 70 that needs to be retained for hot air leveling, and the tin layer 70 on the other side is removed before manufacturing other surfaces, thereby improving warping.

[0047] It should be noted that the alkaline etching step is to etch the motherboard with an alkaline etching solution to complete the pattern on the outer copper plating and the outer base copper.

[0048] Furthermore, in an embodiment of the present invention, before the alkaline etching step, the following steps are also included:

[0049] Sub-board etching: Etching the sub-board to complete the sub-board circuit;

[0050] Lamination: Laminating the daughter boards to form the mother board;

[0051] Drilling: Drill holes on the motherboard;

[0052] Copper plating: Copper plating is performed on the drilled holes to complete the hole metallization.

[0053] Furthermore, in an embodiment of the present invention, in the alkaline etching step, the outer layer circuit is manufactured by external light imaging, copper tin plating, and alkaline etching.

[0054] Further reference Figure 2 and Figure 3 In an embodiment of the present invention, in the soldering step, soldering protection is performed on the outer layer circuit side of the motherboard, and then hot air leveling is performed on the outer layer circuit side and the non-circuit side of the motherboard at the same time.

[0055] It is understandable that before hot air leveling is performed on one side of the outer circuit of the motherboard, the outer circuit is protected by the solder mask 60 .

[0056] Further reference Figure 4 In an embodiment of the present invention, in the dry film step, a layer of dry film is attached to one side of the outer layer circuit of the motherboard.

[0057] It is understandable that the dry film 80 can retain the tin layer 70 on the outer circuit side of the motherboard, thereby preventing the tin layer 70 on the outer circuit side of the motherboard from being removed in the subsequent tin stripping step.

[0058] Further reference Figure 7 In an embodiment of the present invention, in the film stripping step, the dry film attached to one side of the outer layer circuit of the motherboard in the dry film stripping step is removed.

[0059] Further reference Figure 5 and Figure 6 In an embodiment of the present invention, in the tin stripping step, the tin layer on the non-circuit side of the motherboard is removed, and then in the surface treatment step, the non-circuit side of the motherboard is surface treated.

[0060] It is worth noting that in the surface treatment step, various surface treatments, such as gold plating, can be performed on the non-circuit side of the motherboard.

[0061] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A method for improving PCB warping after hot air leveling, characterized in that: The following steps are involved: Alkaline etching: Etching the motherboard to complete the pattern on the outer copper plating and the outer base copper; Solder mask: Make a solder mask on the surface of the motherboard; Hot air leveling: hot air leveling the motherboard; Dry film: Apply dry film on one side of the motherboard; Tinning: remove the tin layer produced by hot air leveling; Surface treatment: Surface treatment of the motherboard; Film removal: Remove the dry film applied in the dry film step.

2. A method for improving PCB warping after hot air leveling according to claim 1, characterized in that: Before the alkaline etching step, the following steps are also included: Sub-board etching: Etching the sub-board to complete the sub-board circuit; Lamination: Laminating the daughter boards to form the mother board; Drilling: Drill holes on the motherboard; Copper plating: Copper plating is performed on the drilled holes to complete the hole metallization.

3. The method for improving PCB warping after hot air leveling according to claim 2, characterized in that: In the alkaline etching step, the outer layer circuit is produced by external light imaging, copper tin plating, and alkaline etching.

4. The method for improving PCB warping after hot air leveling according to claim 2, characterized in that: In the solder mask step, solder mask protection is performed on the outer layer circuit side of the motherboard, and then hot air leveling is performed on the outer layer circuit side and the non-circuit side of the PCB at the same time.

5. The method for improving PCB warping after hot air leveling according to claim 2, characterized in that: In the dry film step, a layer of dry film is applied to one side of the outer circuit of the motherboard.

6. The method for improving PCB warping after hot air leveling according to claim 5, characterized in that: In the film stripping step, the dry film attached to one side of the outer layer circuit of the motherboard in the dry film step is stripped off.

7. The method for improving PCB warping after hot air leveling according to claim 1, characterized in that: In the tin stripping step, the tin layer on the non-circuit side of the motherboard is removed, and then in the surface treatment step, the non-circuit side of the motherboard is surface treated.

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