Circuit board and method for manufacturing a circuit board

Abstract

The application provides a circuit board and a manufacturing method thereof, relates to the technical field of circuit boards, and aims to solve the technical problem of poor high-frequency signal transmission of the circuit board. The manufacturing method comprises the following steps: providing a to-be-processed board piece, the to-be-processed board piece comprising a metal layer, the metal layer having a thick metal area and a thin metal area; forming a first dry film on the thick metal area and the thin metal area; placing a convex pressing plate on the first dry film, the convex pressing plate having a protrusion matched with the thin metal area, and the protrusion extrudes and adheres the first dry film to the thin metal area. The protrusion matched with the thin metal area extrudes and adheres the first dry film to the thin metal area, so that there is no gap between the first dry film and the thin metal area, and the circuit pattern of the thin metal area and the thick metal area can be manufactured by the first dry film once, the circuit pattern is complete, the manufacturing process is simplified, and high-frequency signal transmission is good. In addition, the circuit pattern of the thin metal area and the thick metal area is smoothly connected, so as to ensure the docking accuracy and thus good high-frequency signal transmission.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board, and particularly to a circuit board and a manufacturing method thereof. BACKGROUND

[0002] With the progress of science and technology, the degree of automation is getting higher and higher. As one of the important components in various electronic products, a printed circuit board (PCB) is a support body and a carrier of electrical connection for electronic components in electronic products, and has a great influence on the performance of electronic products.

[0003] In order to take into account the integrity of the signal and good heat dissipation, part of the area of the circuit board is a thin copper area to reduce the insertion loss of high-frequency signals and ensure the integrity of high-frequency signals; part of the area of the circuit board is a thick copper area to ensure the passability of current and reduce the heat effect generated by the current passing through. The circuit pattern of the thin copper area and the circuit pattern of the thick copper area are usually connected to form an integral whole, and the circuit pattern of the thin copper area and the circuit pattern of the thick copper area have a height difference, and the junction of the circuit patterns is in a stepped shape.

[0004] However, in the traditional manufacturing process of the above-mentioned circuit board, the connection precision of the circuit patterns of the thin copper area and the thick copper area is low or the circuit patterns are incomplete, resulting in poor high-frequency signal transmission of the circuit board. SUMMARY

[0005] In view of the above problems, the embodiments of the present application provide a circuit board and a manufacturing method thereof for improving the high-frequency signal transmission effect of the circuit board.

[0006] In order to achieve the above-mentioned purpose, in a first aspect, the embodiments of the present application provide a manufacturing method of a circuit board, which comprises: providing a to-be-processed board piece, the to-be-processed board piece comprising a metal layer, the metal layer having a thick metal area and a thin metal area;

[0007] forming a first dry film on the thick metal area and the thin metal area;

[0008] placing a convex pressing plate on the first dry film, the convex pressing plate having a protrusion matched with the thin metal area, the protrusion extruding and pasting the first dry film on the thin metal area.

[0009] In some possible embodiments, the height of the protrusion is greater than the sum of the height difference between the thick metal area and the thin metal area and the thickness of the first dry film;

[0010] The difference between the spacing between the circumferential profile of the protrusion and the circumferential profile of the thin metal area and the thickness of the first dry film is 10-15 μm.

[0011] In some possible embodiments, a plate to be processed is provided, the plate to be processed comprising a metal layer, the metal layer having a thick metal area and a thin metal area, comprising:

[0012] A core plate is provided;

[0013] A metal layer is formed, and a substrate layer is formed between the core plate and the metal layer;

[0014] A portion of the metal layer is thinned to form the thin metal area, and the portion not thinned forms the thick metal area.

[0015] In some possible embodiments, the convex pressing plate further comprises a bottom plate, and the protrusions are arranged on the bottom plate;

[0016] The convex pressing plate is placed on the first dry film, the convex pressing plate has protrusions matched with the thin metal area, and the protrusions are arranged before the first dry film is attached to the thin metal area, and the convex pressing plate further comprises:

[0017] An initial pressing plate is provided;

[0018] A milling file of the initial pressing plate is determined according to a shrinkage coefficient of the plate to be processed;

[0019] The initial pressing plate is depth-milled according to the milling file to form the bottom plate and the protrusions.

[0020] In some possible embodiments, the material of the initial pressing plate is the same as that of the substrate layer, and the thickness of the initial pressing plate is 1-1.5 mm.

[0021] In some possible embodiments, the plate to be processed is provided with a positioning hole, the convex pressing plate is provided with a positioning hole, and the positioning hole and the positioning hole are formed by using the same drilling file.

[0022] In some possible embodiments, the convex pressing plate is placed on the first dry film, the convex pressing plate has protrusions matched with the thin metal area, and the protrusions are arranged after the first dry film is attached to the thin metal area, and the convex pressing plate further comprises:

[0023] The convex pressing plate and the plate to be processed are hot-pressed by using a hot-pressing roller.

[0024] In some possible embodiments, the temperature of the hot-pressing roller is 110-130°, the pressure of the hot-pressing roller is 4-5 Kg / cm 2 , and the conveying speed of the hot-pressing roller is 1.5-2.0 m / min.

[0025] In some possible embodiments, after the convex pressing plate and the plate to be processed are hot-pressed by using the hot-pressing roller, the method further comprises:

[0026] removing the convex pressing plate;

[0027] exposing and developing the first dry film to form an etching pattern; and etching the thin metal area and the thick metal area with the first dry film having the etching pattern as a mask to form a circuit pattern.

[0028] The manufacturing method of the circuit board provided by the embodiment of the present application can press the first dry film against the thin metal area with the protrusion, so that there is no gap between the first dry film and the thin metal area, and the circuit pattern of the thin metal area and the thick metal area can be manufactured by the first dry film once. Through the above arrangement, on the one hand, the circuit pattern is complete, the manufacturing process is simplified, and the high-frequency signal transmission can be ensured; on the other hand, the circuit pattern of the thin metal area and the thick metal area is smoothly transitioned, the docking precision can be ensured, and the high-frequency signal transmission can be further ensured.

[0029] In a second aspect, the circuit board provided by the embodiment of the present application is formed by the manufacturing method described above, so that the circuit board at least has the advantage of good high-frequency signal transmission, and specific effects are described above and will not be described here again.

[0030] In addition to the technical problems solved by the embodiments of the present application described above, the technical features constituting the technical solutions, and the beneficial effects brought by the technical features, the other technical problems solved by the circuit board and the manufacturing method of the circuit board provided by the embodiments of the present application, the other technical features included in the technical solutions, and the beneficial effects brought by the technical features will be further described in detail in the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0032] Figure 1 a schematic diagram of infiltration in the related art;

[0033] Figure 2 a schematic diagram of misalignment in the related art;

[0034] Figure 3 a flowchart of the manufacturing method of the circuit board in the embodiment of the present application;

[0035] Figure 4 a schematic diagram of the to-be-processed board in the embodiment of the present application;

[0036] Figure 5 This is a top view of the plate to be processed in an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the formation of the first dry film in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the placement of the convex pressure plate in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the initial pressure plate in an embodiment of the present invention;

[0040] Figure 9 This is a schematic diagram of the process after removing the convex pressure plate in an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 10 - Board to be processed; 11 - Core board;

[0043] 12-Copper foil layer; 13-Substrate layer;

[0044] 14-Metal layer; 15-Positioning hole;

[0045] 20 - First dry film; 30 - Convex pressure plate;

[0046] 31-Base plate; 32-Protrusion;

[0047] 33 - Alignment hole; 34 - Initial pressure plate;

[0048] 40 - Circuit diagram. Detailed Implementation

[0049] In related technologies, the low accuracy of the wiring patterns between thin and thick copper areas, or incomplete wiring patterns, leads to poor high-frequency signal transmission on the circuit board. The inventors discovered that the wiring patterns between the thin and thick copper areas are stepped, with a height difference. The transition between these two wiring patterns is a challenge in circuit board manufacturing, and is often achieved using the following two methods:

[0050] One method involves first creating a thin copper area circuit pattern, then electroplating a thick copper layer, and finally creating the thick copper circuit pattern. The specific process includes: pretreatment → film lamination → exposure → development → etching → film stripping (completing the thin copper area circuit pattern) → pretreatment → film lamination → exposure → electroplating thick copper → film stripping → pretreatment → film lamination → exposure → development → tin plating → film stripping → etching → tin stripping (completing the thick copper area circuit pattern). This method is complex, for example... Figure 1As shown, there is a plating leakage at the joint of the circuit pattern 40 of the thin copper area and the circuit pattern 40 of the thick copper area, causing a short circuit of the circuit board and a low yield of the circuit board; on the other hand, as shown, the joint precision of the circuit pattern 40 of the thin copper area and the circuit pattern 40 of the thick copper area is low, and there is a misalignment problem, and the high-frequency signal transmission in this part is poor. Figure 2 As shown, there is a plating leakage at the joint of the circuit pattern 40 of the thin copper area and the circuit pattern 40 of the thick copper area, causing a short circuit of the circuit board and a low yield of the circuit board; on the other hand, as shown, the joint precision of the circuit pattern 40 of the thin copper area and the circuit pattern 40 of the thick copper area is low, and there is a misalignment problem, and the high-frequency signal transmission in this part is poor.

[0051] Another is to simultaneously manufacture the circuit pattern of the thin copper area and the circuit pattern of the thick copper area, and the specific manufacturing process includes: full-face electroplating → pretreatment → film pasting → exposure → development → local copper reduction → pretreatment → wet film screen printing / coating → pre-baking → exposure → development → film pasting (dry film hole sealing) → exposure → development → etching → film stripping (the circuit pattern of the thin copper area and the circuit pattern of the thick copper area are completed). This manufacturing method can ensure the joint precision of the circuit pattern of the thin copper area and the circuit pattern of the thick copper area, and avoid misalignment. However, since the resolution of the wet film after exposure is not as good as that of the dry film, it is difficult to meet the precision requirement of the circuit pattern, and since the wet film does not have the hole sealing capability, a dry film needs to be pasted again to seal the metallized through hole after the wet film is completed, so the wet film needs to be subjected to two exposures and two developments, and the two exposures will affect the film stripping effect and easily cause incomplete film stripping; the two developments will cause the wet film to be overdeveloped to a certain extent, resulting in incomplete circuit pattern and poor high-frequency signal transmission.

[0052] In view of this, the embodiment of the present application provides a manufacturing method of a circuit board, the protrusions of the convex pressing plate protrude into the thin metal area, the first dry film is pressed and pasted on the thin metal area by the protrusions, so that the first dry film is tightly pasted with the thin metal area without gaps, and the subsequent circuit pattern of the thin metal area and the thick metal area can be completed by the first dry film once. On the one hand, the circuit pattern is complete, the manufacturing process is simplified, and the high-frequency signal transmission can be ensured to be good; on the other hand, the circuit pattern of the thin metal area and the thick metal area is smoothly transitioned, the joint precision can be ensured, and the high-frequency signal transmission can be further ensured to be good.

[0053] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more apparent and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0054] The first aspect of the embodiment of the present application provides a manufacturing method of a circuit board, referring to Figure 3 The manufacturing method specifically includes the following steps:

[0055] Step S100: providing a to-be-processed board piece, the to-be-processed board piece including a metal layer, the metal layer having a thick metal area and a thin metal area.

[0056] Reference Figure 4 The plate member 10 to be processed can include a core plate 11, and a metal layer 14 disposed on the core plate 11, and a base material layer 13 disposed between the core plate 11 and the metal layer 14, which insulates and separates the core plate 11 and the metal layer 14.

[0057] The core plate 11 can be a double-sided copper-clad core plate, which is convenient for connecting electrical elements on opposite sides of the core plate 11. For example, the core plate 11 can be an organic resin-based copper-clad core plate, a glass fiber cloth-based copper-clad core plate, a paper-based copper-clad core plate, a composite-based copper-clad core plate, an aramid fiber non-woven fabric-based copper-clad core plate, or a synthetic fiber-based copper-clad core plate, etc.

[0058] Preferably, the core plate 11 can be a polypropylene (PP) copper-clad core plate, that is, the core plate 11 includes a polypropylene layer, and copper foil layers 12 disposed on opposite sides of the polypropylene layer. The copper foil layers 12, the polypropylene layer, and the copper foil layers 12 are sequentially stacked and hot-pressed to form a copper-clad laminated plate (CCL).

[0059] Further, the base material layer 13 can be an insulating material to achieve isolation between the metal layer 14 and the core plate 11. The metal layer 14 can be a copper layer, and the material of the metal layer 14 is copper, which has good electrical conductivity on the one hand, and is easy to adhere to the base material layer 13 and not easy to fall off on the other hand. In addition, the copper layer is also easy to perform a patterning process, which is convenient for forming a circuit pattern 40.

[0060] In some possible embodiments, at least one side of the core plate 11 is provided with the metal layer 14, and the base material layer 13 is disposed between the core plate 11 and the metal layer 14. That is, the core plate 11 can be provided with the metal layer 14 on one side or on both sides, and the metal layer 14 and the core plate 11 can be electrically connected by a via. In the embodiments of the present application, as shown in Figure 4 The two sides of the core plate 11 are provided with the metal layer 14, that is, the metal layer 14, the base material layer 13, the core plate 11, the base material layer 13, and the metal layer 14 are sequentially stacked.

[0061] When the core plate 11 is provided with the metal layer 14 on one side, the metal layer 14 has a thick metal area and a thin metal area. When the core plate 11 is provided with the metal layer 14 on both sides, at least one side of the metal layer 14 has a thick metal area and a thin metal area. The thickness of the metal layer 14 in the thick metal area is greater than the thickness of the metal layer 14 in the thin metal area.

[0062] For example, the metal layer 14 on the upper side of the core plate 11 has a thick metal area and a thin metal area, and the metal layer 14 on the lower side of the core plate 11 has a constant thickness, that is, the metal layer 14 is uniform. The thin metal area isFigure 4 As shown at location A, the thick metal region is as Figure 4 As shown at location B.

[0063] In one possible implementation, a plate to be processed is provided, the plate to be processed comprising a metal layer, the metal layer having a thick metal region and a thin metal region, comprising:

[0064] Step S110: providing a core plate.

[0065] Specifically, the core plate 11 is obtained by cutting, and the core plate 11 is a double-sided copper-clad core plate. The core layer of the double-sided copper-clad core plate 11 is a polypropylene layer, and the opposite sides of the polypropylene layer are provided with copper foil layers 12.

[0066] Step S120: forming a metal layer and a base material layer between the core plate and the metal layer.

[0067] The base material layer 13 is formed on at least one side of the core plate 11, and the metal layer 14 is formed on the base material layer 13. For example, the base material layer 13 can be made of an insulating material, such as epoxy resin or glass fiber. The metal layer 14 can be a copper layer formed on the entire base material layer 13 by an electroplating process.

[0068] In one possible embodiment, when forming the copper layer, the outer copper foil layer can be first laminated on the base material layer 13 by using a prepreg, then the laminated plate is drilled and full-plate electroplating is performed. Through the above arrangement, on the one hand, the drilled holes are metallized to form vias; on the other hand, an electroplated layer is formed on the outer copper foil layer, and the outer copper foil layer and the electroplated layer form the metal layer 14.

[0069] Step S130: thinning part of the metal layer to form a thin metal region, and the part not thinned forms a thick metal region.

[0070] In some possible implementations, a second dry film is pasted on the metal layer 14 by using a film pasting machine; then the second dry film in the region to be thinned is removed by using the exposure and development method; and then the metal layer 14 in the region to be thinned is chemically thinned to form a thin metal region, and the region not chemically thinned forms a thick metal region.

[0071] In this case, the temperature when pasting the second dry film can be 120°C, the pressure can be 0.4-0.6 MPa, and the speed can be 2-2.8 m / min. The metal layer 14 in the region to be thinned can be obtained by multiple etching to obtain a metal layer 14 with a certain thickness. Multiple etching is used to control the thickness difference of the metal layer 14 of the thin metal region formed, so that more fine circuit patterns can be obtained subsequently.

[0072] After the thin metal region and the thick metal region are formed, the metal layer 14 can be pretreated to facilitate the subsequent manufacturing of the first dry film 20 (see Figure 6). Specifically, the pre-treatment can include, in sequence, oil removal, overflow water washing, clean water washing, micro-etching, overflow water washing, pickling, overflow water washing, DI water washing, and plate drying.

[0073] It should be noted that, referring to Figure 5 , before the metal layer 14 is thinned or after the metal layer 14 is thinned, a positioning hole 15 can be formed on the surface of the metal layer 14, the substrate layer 13, and the core plate 11 away from the core plate 11, and the positioning hole 15 can be formed on the circumferential edge of the surface, so that the formed to-be-processed plate 10 has the positioning hole 15, and the to-be-processed plate 10 is convenient to install and position.

[0074] Step S200: forming a first dry film on the thick metal area and the thin metal area.

[0075] Referring to Figure 6 , specifically, the first dry film 20 is pasted on the thick metal area and the thin metal area by a film pasting machine. When the first dry film 20 is pasted, the temperature can be 100-140°C, the pressure can be 0.4-0.6 MPa, and the speed can be 2-2.8 m / min. As shown in Figure 6 , after the first dry film 20 is pasted, due to the height difference between the thick metal area and the thin metal area, the first dry film 20 is prone to have a gap in the thin metal area, which affects the accuracy of the subsequent circuit pattern.

[0076] Step S300: placing a convex pressing plate on the first dry film, the convex pressing plate having a protrusion matching the thin metal area, and the protrusion pasting the first dry film on the thin metal area.

[0077] Referring to Figure 7 , in some possible embodiments, the convex pressing plate 30 includes a bottom plate 31 and a protrusion 32 arranged on the bottom plate 31, and the bottom plate 31 and the protrusion 32 can be an integrated structure. The bottom plate 31 is used to support the protrusion 32, and the protrusion 32 matches the thin metal area. The cross-sectional shape of the protrusion 32 can be the same as that of the thin metal area, and the cross-sectional size of the protrusion 32 is smaller than that of the thin metal area.

[0078] Through the above arrangement, the protrusion 32 can extend into the thin metal area to paste the first dry film 20 on the thin metal area. Specifically, the thin metal area is a groove relative to the thick metal area, the protrusion 32 can extend into the groove, and the first dry film 20 is pasted on the bottom and the side wall of the groove, so that there is no gap between the first dry film 20 and the thin metal area. That is, the protrusion 32 can paste the first dry film 20 on the entire continuous surface of the metal layer 14 away from the core plate 11, so that there is no gap between the first dry film 20 and the metal layer 14.

[0079] In some preferred embodiments, the height of the protrusion 32 is greater than the sum of the height difference between the thick metal area and the thin metal area and the thickness of the first dry film 20. In this way, as shown in Figure 7 The bottom plate 31 is not in contact with the first dry film 20 of the thick metal area, i.e. there is a gap between the bottom plate 31 and the first dry film 20 of the thick metal area, thereby avoiding extrusion of the bottom plate 31 to the first dry film 20 of the thick metal area, so that only the protrusion 32 in the convex pressing plate 30 is in the working position and is in contact with the first dry film 20.

[0080] The difference between the gap between the circumferential profile of the protrusion 32 and the circumferential profile of the thin metal area and the thickness of the first dry film 20 is 10-15 μm. For example, the thickness of the first dry film 20 is 40 μm, and the gap between the circumferential profile of the protrusion 32 and the circumferential profile of the thin metal area can be 50-55 μm. In this way, on the one hand, the first dry film 20 can be completely attached to the thin metal area by the protrusion 32; on the other hand, the first dry film 20 can be prevented from being broken when the first dry film 20 is pressed to the thin metal area by the protrusion 32, thereby ensuring the continuity of the first dry film 20.

[0081] The number of convex pressing plates 30 matches the number of the to-be-processed plate pieces 10, i.e. the convex pressing plate 30 and the to-be-processed plate piece 10 correspond one by one, so that multiple to-be-processed plate pieces 10 can be processed at the same time to improve the production efficiency.

[0082] In some possible implementations, the convex pressing plate is placed on the first dry film, the convex pressing plate has a protrusion matched with the thin metal area, and the protrusion is used to attach the first dry film to the thin metal area before the first dry film is attached to the thin metal area, and the convex pressing plate further comprises:

[0083] Step S310: providing an initial pressing plate.

[0084] Specifically, referring to Figure 8 The initial pressing plate 34 can be a plate material, and the material thereof can be the same as that of the base material layer 13, so that the materials on both sides of the first dry film 20 are the same, thereby ensuring the consistency of both sides of the first dry film 20 in the subsequent processing process. Preferably, the thickness of the initial pressing plate 34 can be 1-1.5 mm.

[0085] The surface of the initial pressing plate 34 facing the to-be-processed plate piece 10 can be provided with a positioning hole 33, so that the convex pressing plate 30 formed subsequently has the positioning hole 33. The positioning hole 33 of the convex pressing plate 30 corresponds to the positioning hole 15 of the to-be-processed plate piece 10, thereby facilitating the positioning of the convex pressing plate 30 and the to-be-processed plate piece 10.

[0086] In some possible implementations, the positioning hole 15 of the to-be-processed plate piece 10 and the positioning hole 33 of the convex pressing plate 30 are formed using the same drilling tape material, and the positioning hole 15 of the to-be-processed plate piece 10 and the positioning hole 33 of the convex pressing plate 30 can be in a mirror image relationship.

[0087] Step S320: determining the milling strip file of the initial pressing plate according to the expansion coefficient of the plate to be processed.

[0088] Specifically, the milling strip file of the initial pressing plate 34 can be obtained according to the expansion coefficient of the plate to be processed 10 and in combination with the outer shape data of the plate to be processed 10, and the milling strip file reflects the milling strip area of the initial pressing plate 34, which is processed by milling. The expansion coefficient of the plate to be processed 10 is obtained according to the expansion amount of the plate to be processed 10. The expansion amount can be obtained by comparing the measured position of the target position on the plate to be processed 10 by X-Ray measurement with the theoretical position, or by optical secondary dimension or optical / mechanical tertiary dimension measurement.

[0089] Step S330: performing depth milling processing on the initial pressing plate according to the milling strip file to form the bottom plate and the protrusion.

[0090] The initial pressing plate 34 is processed by milling to remove part of the initial pressing plate 34 to form the protrusion 32 and the bottom plate 31. The milling processing can be performed by a numerical control milling machine, and the milling processing can be given a depth, i.e., the thickness of the initial pressing plate 34 removed by milling is equal, so that the height of the obtained protrusion 32 is consistent.

[0091] In summary, in the embodiment of the present application, the protrusion 32 matched with the thin metal area extrudes and covers the first dry film 20 on the thin metal area, so that there is no gap between the first dry film 20 and the thin metal area, and the circuit pattern of the thin metal area and the thick metal area can be completed by the first dry film 20. Through the above setting, on the one hand, the circuit pattern is complete, the production process is simplified, and the high-frequency signal transmission can be ensured to be good; on the other hand, the circuit pattern of the thin metal area and the thick metal area is smoothly transitioned, the docking accuracy can be ensured, and the high-frequency signal transmission can be further ensured to be good.

[0092] In some possible embodiments, after placing the convex pressing plate on the first dry film, the convex pressing plate has a protrusion matched with the thin metal area, and the protrusion covers the first dry film on the thin metal area (step S300), further comprising:

[0093] Step S400: hot pressing the convex pressing plate and the plate to be processed by using a hot pressing roller.

[0094] Specifically, after placing the convex pressing plate 30 on the first dry film 20, the convex pressing plate 30 and the plate to be processed 10 can be hot pressed on a film laminating machine. The film laminating machine adopts a film-free air pressure mode, i.e., no film is laminated on the convex pressing plate 30, and only a hot pressing roller is used for hot pressing. Preferably, the temperature of the hot pressing roller is 110-130°, and the pressure of the hot pressing roller is 4-5 Kg / cm 2The conveying speed of the convex pressing plate 30 and the plate member 10 relative to the hot pressing roller is 1.5-2 m / min.

[0095] It should be noted that, in order to ensure the alignment of the convex pressing plate 30 and the plate member 10, when the convex pressing plate 30 is invertedly buckled on the plate member 10, the alignment hole 33 of the convex pressing plate 30 coincides with the positioning hole 15 of the plate member 10, so as to complete the alignment of the convex pressing plate 30 and the plate member 10, and further make the protrusion 32 located in the center region of the thin metal region, so as to ensure that the first dry film 20 is tightly attached to the thin metal region.

[0096] Further, in order to avoid the movement of the convex pressing plate 30 relative to the plate member 10 during hot pressing, after the convex pressing plate 30 is placed on the first dry film 20, the convex pressing plate 30 and the plate member 10 are fixed. For example, the convex pressing plate 30 and the plate member 10 are fixed by adhesive tape, so as to avoid the movement of the convex pressing plate 30 relative to the plate member 10 caused by the hot pressing roller during hot pressing.

[0097] In some possible embodiments, after the hot pressing of the convex pressing plate and the plate member by the hot pressing roller (step S400), the method further includes:

[0098] Step S500: removing the convex pressing plate.

[0099] Reference Figure 9 After the convex pressing plate 30 is removed, the first dry film 20 is tightly and seamlessly attached to the thin metal region and the thick metal region. The convex pressing plate 30 can be repeatedly used, so as to improve the utilization rate of the convex pressing plate 30 and reduce the generation cost of the circuit board.

[0100] Step S600: exposing and developing the first dry film, so as to form an etching pattern on the first dry film.

[0101] Specifically, the first dry film 20 and the plate member 10 are placed into an exposure machine, and the first dry film 20 is exposed. Then, the exposed first dry film 20 and the plate member 10 are placed into a developing machine with a developing solution for development. Through the exposure and development, the etching pattern is formed on the first dry film 20, and part of the thin metal region and the thick metal region is exposed. The developing solution is circulated, the utilization rate of the developing solution is improved, the waste of the developing solution is avoided, the developing temperature is not more than 30 ℃, and the development is performed under low pressure and low oxygen condition, so as to avoid the generation of bubbles in the developing solution.

[0102] Step S700: taking the first dry film with the etching pattern as a mask, and etching the thin metal region and the thick metal region to form a circuit pattern.

[0103] Specifically, the developed first dry film 20 and the to-be-processed plate 10 are placed into an etching machine with etching liquid to perform etching, so as to form circuit patterns in the thin metal area and the thick metal area. In this way, the circuit patterns in the thin metal area and the thick metal area are formed through the same etching process, and the butt joint precision is high, and the misalignment of the circuit patterns can be reduced or avoided.

[0104] The second aspect of the embodiments of the present application further provides a circuit board formed by the manufacturing method, and the circuit board has at least the advantage of good high-frequency signal transmission, and the specific effects are described above and will not be repeated here.

[0105] In the description of the present specification, each embodiment or implementation is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between each embodiment can be referred to each other.

[0106] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0107] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a circuit board, characterized in that, include: A board to be processed is provided, the board to be processed including a metal layer, the metal layer having a thick metal region and a thin metal region; A first dry film is formed on the thick metal region and the thin metal region; A convex pressure plate is placed on the first dry film. The convex pressure plate has protrusions adapted to the thin metal region. The protrusions press and adhere the first dry film to the thin metal region. The height of the protrusions is greater than the sum of the height difference between the thick metal region and the thin metal region and the thickness of the first dry film. The difference between the distance between the circumferential contour of the protrusions and the circumferential contour of the thin metal region and the thickness of the first dry film is 10-15 μm. The convex pressure plate further includes a base plate, and the protrusion is disposed on the base plate; the convex pressure plate is placed on the first dry film, the convex pressure plate having a protrusion adapted to the thin metal region, and the protrusion further includes the following before the first dry film is adhered to the thin metal region: Provide the initial pressure plate; The milling profile of the initial pressure plate is determined based on the expansion and contraction coefficient of the plate to be processed; the expansion and contraction coefficient of the plate to be processed is obtained based on the expansion and contraction amount of the plate to be processed. The initial pressure plate is milled to a fixed depth according to the milling file to form the base plate and the protrusion.

2. The manufacturing method according to claim 1, characterized in that, A board to be processed is provided, the board including a metal layer having a thick metal region and a thin metal region, including: Provide core boards; A metal layer is formed, and a substrate layer is located between the core plate and the metal layer; A portion of the metal layer is thinned to form the thin metal region, while the unthinned portion forms the thick metal region.

3. The manufacturing method according to claim 2, characterized in that, The initial pressure plate is made of the same material as the substrate layer, and the thickness of the initial pressure plate is 1-1.5 mm.

4. The manufacturing method according to any one of claims 1-3, characterized in that, The plate to be processed is provided with positioning holes, and the convex pressure plate is provided with alignment holes. The positioning holes and the alignment holes are formed using the same drill bit file.

5. The manufacturing method according to any one of claims 1-3, characterized in that, A convex pressure plate is placed on the first dry film. The convex pressure plate has protrusions adapted to the thin metal region. After the protrusions adhere the first dry film to the thin metal region, the plate further includes: The convex pressure plate and the plate to be processed are hot-pressed using hot-pressing rollers.

6. The manufacturing method according to claim 5, characterized in that, The temperature of the hot-pressing roller is 110°-130°, the pressure of the hot-pressing roller is 4-5Kg / cm², and the conveying speed of the hot-pressing roller is 1.5-2.0m / min.

7. The manufacturing method according to claim 5, characterized in that, After hot pressing the convex pressure plate and the workpiece to be processed using hot pressing rollers, the process further includes: Remove the convex pressure plate; The first dry film is exposed and developed to form an etched pattern on the first dry film. Using the first dry film with the etching pattern as a mask, the thin metal region and the thick metal region are etched to form a circuit pattern.

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