Method for manufacturing circuit board of thick copper slope circuit

Abstract

The invention discloses a method for manufacturing a circuit board of a thick copper slope circuit, which comprises the following steps of: attaching a first dry film layer on a thick copper layer, manufacturing a dry film pattern, retaining the dry film layer on the thick copper circuit, developing and removing the dry film layer on a thin copper circuit, developing the dry film layer on the slope circuit to form a matrix developing pattern, etching a slope circuit area to form a matrix etching pattern, and manufacturing the circuit board of the thick copper slope circuit. The method comprises the following steps of: grinding off a thick copper slope line, processing a line pattern, manufacturing a second dry film pattern, forming a surrounding pattern of all slope line areas, manufacturing a first solder mask layer in the surrounding pattern, manufacturing a second solder mask layer in other areas, and carrying out post-process processing to form a circuit board of the thick copper slope line; the processing precision and reliability of a slope circuit are improved through a mode of taking chemical processing of developing and etching as a main mode and taking polishing as an auxiliary mode, and a solder mask layer with the thickness reaching the standard and a complete covering effect is formed through manufacturing an encircling pattern and manufacturing a first solder mask layer and a second solder mask layer; the whole machining process effectively improves the machining precision and reliability.

Description

Technical Field

[0001] The invention relates to the field of circuit board design and processing, and in particular to a method for manufacturing a circuit board with a thick copper slope circuit. Background Art

[0002] The circuit board industry generally refers to circuit boards with a copper thickness of more than 70μm as thick copper circuit boards. Thick copper circuit boards are increasingly widely used in power supply systems, industrial control systems, power electronics systems and other fields due to their advantages such as large current carrying capacity, high heat dissipation, high reliability, strong mechanical properties and strong support.

[0003] If the thick copper circuit board is designed to be plugged in and connected to components such as connectors, gold fingers will also be made on its surface. However, if the plug-in connector is a normal current-carrying socket design, the gold finger end of the thick copper circuit board needs to be "reduced" to reduce the copper thickness to the regular copper thickness, for example: reduced to 30μm to 50μm, to form a thin copper area, and then electroplated with gold fingers to form a gold finger plug with normal current carrying capacity and thickness.

[0004] For the above structural design, under normal circumstances, it is generally implemented by directly adopting two circuit pattern processing methods, that is, the first time, the circuit pattern processing method (sticking dry film → exposure → development → etching → film stripping) is used to process the circuit pattern of the whole board, and the second time, the dry film is used to cover the thick copper area that does not need to be etched to reduce copper, exposing the gold finger end area that needs to be etched to reduce copper, and etching is performed to make the circuit pattern form a "stepped circuit" where the thick copper and thin copper areas are connected to meet the gold finger processing.

[0005] However, for a type of thick copper circuit board that has high requirements for current stability or signal stability, a stepped circuit is formed according to the above processing method. Since the circuit resistance value of the thick copper area is small and the current carrying capacity is large, while the resistance value of the thin copper area is large and the current carrying capacity is small, if the circuit is in a stepped shape, a jump-like mutation phenomenon will occur when the current or signal is transmitted from the thick copper area to the conventional copper thick area, or from the conventional copper thick area to the thick copper area, resulting in large current and signal losses. In severe cases, the thin copper area circuit may be burned by the instantaneous large current impact when power is turned on.

[0006] Therefore, to address this problem, a "slope line" design method has emerged in the circuit layout, which transitions from the thick copper area to the thin copper area. That is, the original "step line" is designed to have a certain slope that gradually becomes thinner from the thick copper area to the thin copper area, forming a buffer area for the line when conducting current or signals, reducing the sudden change phenomenon of the step line, reducing the loss of current or signals, and increasing the service life of the line.

[0007] The "slope circuit" is a structure designed in the plane direction of the circuit board (not the vertical direction). Therefore, it is difficult to directly use multiple circuit pattern processing methods to produce it. Mechanical processing is usually used, that is, first the circuit pattern area where the slope circuit and thin copper area need to be produced is cut by CNC precision milling to form the slope circuit and thin copper area, and then the circuit pattern processing method is used to produce the thick copper area circuit and the thin copper area circuit.

[0008] However, when using mechanical processing methods, on the one hand, the accuracy can be controlled within ±10μm at most under the requirements of batch processing. For high-precision slope line graphics with an accuracy of within ±10μm, it is difficult to meet the processing accuracy requirements; on the other hand, the mechanical cutting processing method has a greater impact on the expansion and shrinkage of the product, which may cause excessive deformation during processing or excessive expansion and shrinkage after processing, affecting subsequent process processing.

[0009] At the same time, when the circuit is designed as a slope circuit, the production method of the solder mask layer cannot be used for the step circuit. The step circuit generally first screens the solder mask ink at the convex corner of the step to make a local solder mask layer of the convex corner, and then screens the solder mask ink as a whole to form an overall solder mask layer, or fills the step position with glue first, and then screen prints the solder mask layer. However, this method is not suitable for the solder mask processing of the slope circuit because there is no direct step position for the slope circuit, so there is no need to first process the convex corner or concave corner position. Therefore, this method is not suitable for the solder mask processing of the slope circuit.

[0010] Based on the above background and problems, it is necessary to provide a circuit board manufacturing method that can effectively realize batch processing and has high precision thick copper slope circuits. Summary of the invention

[0011] The present invention aims to solve the problem that it is difficult to meet the high precision machining requirements when the slope circuit pattern is made by mechanical processing in the prior art, and the problem of making a solder mask layer after the slope circuit is formed. A method for making a circuit board with a thick copper slope circuit is provided, wherein the thick copper slope circuit is composed of a thick copper circuit, a slope circuit, and a thin copper circuit in a continuous manner. The method comprises the following steps: S10: taking a thick copper clad laminate, and attaching a first dry film layer on the thick copper layer of the thick copper clad laminate; S20: sequentially exposing and developing the first dry film layer, retaining the first dry film layer covering the thick copper circuit to be processed, developing the first dry film layer covering the thin copper circuit to be processed, and developing the first dry film layer on the slope circuit to be processed to form a matrix development pattern; S30: performing etching processing to form a matrix etching pattern in the slope circuit area to be processed, and then performing film stripping processing; S40: performing a grinding process to grind away the matrix etching pattern; S50: performing circuit pattern transfer processing to form a slope circuit pattern plate; S60: attaching a second dry film layer to the slope circuit pattern board, and sequentially exposing and developing to form a second dry film pattern, wherein the second dry film pattern covers the periphery of the entire slope circuit area to form a dry film enclosed pattern circuit board; S70: performing a first screen printing of solder mask ink in the area covered by the second dry film pattern, and performing a first pre-bake, a first development, a first post-curing bake, and a dry film removal in sequence to form a first solder mask layer, thereby forming a first solder mask layer circuit board as a whole; S80: forming a second solder resist layer on the first solder resist layer circuit board, wherein the second solder resist layer covers the area where the solder resist layer needs to be formed except the first solder resist layer, to form a solder resist layer circuit board; S90: performing post-processing on the solder mask circuit board to form the circuit board with the thick copper slope circuit.

[0012] Furthermore, the matrix developing pattern is composed of a number of single-row developing geometric figures regularly arranged in the developing area; the single-row developing geometric figure is a developing array including one or more independent geometric figures; the developing size of the developing array is set to increase from smaller to larger from one end of the thick copper circuit to be processed to one end of the thin copper circuit to be processed.

[0013] Furthermore, the independent geometric figures are circular figures; and the single-row development geometric figures are development arrays comprising more than or equal to 2 independent circular figures.

[0014] Furthermore, the diameter of the smaller circular figure is 0.015 mm to 0.05 mm, and the diameter of the larger circular figure is 0.05 mm to 0.125 mm.

[0015] Furthermore, the independent geometric figure is an isosceles trapezoidal figure; and the single-row development geometric figure is a development array including one of the isosceles trapezoidal figures.

[0016] Furthermore, the width of the short side of the isosceles trapezoidal figure is 0.015 mm to 0.05 mm, and the width of the long side of the isosceles trapezoidal figure is 0.05 mm to 0.125 mm.

[0017] Furthermore, two waist sides of the isosceles trapezoidal figure are arc-shaped sides.

[0018] Furthermore, the grinding process is performed by using a sanding belt grinding plate, and the sanding belt grinding plate is used to grind the matrix etching pattern by adjusting the grinding pressure of the sanding belt grinding plate and the distance between the sanding belt and the height of the slope line according to the slope shape of the slope line.

[0019] Furthermore, the area of ​​the dry film enclosed pattern extends unilaterally toward the area of ​​the thick copper circuit and the area of ​​the thin copper circuit by 0.1 mm to 2.0 mm.

[0020] Furthermore, the second solder resist layer partially covers the first solder resist layer.

[0021] The technical solution of the present invention adopts a slope circuit design, which can form a buffer zone for current or signal transmission. During processing, a matrix development pattern is made, so that the first dry film layer of the slope circuit area to be processed is formed to provide a differentiated liquid circulation exchange channel for subsequent etching processing. Then, a matrix etching pattern is formed through etching processing. The matrix etching pattern forms a differentiated etching pattern under the control of the matrix development pattern on the flow capacity and flow rate of the etching liquid. Through grinding and circuit pattern transfer processing, a slope circuit pattern board with thick copper circuits, slope circuits, and thin copper circuits is produced. ; A dry film enclosing pattern is made in the slope circuit area, and a first solder resist layer is made in the dry film enclosing pattern, so that the solder resist layer in the slope circuit area can effectively cover the slope circuit, and then a second solder resist layer is made to form an overall solder resist layer. The processing can effectively improve the coverage performance of the solder resist, ensure that the solder resist layer meets the thickness of the thick copper circuit, and prevent the solder resist ink from oil accumulation and cross flow in the slope circuit area, thereby improving the functionality and processability of the solder resist layer and improving the processing accuracy; the effective combination of the overall processing flow can produce a circuit board with a thick copper slope circuit with high precision and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 is a process flow chart of a manufacturing method according to an embodiment of the present invention; Figure 2 A schematic diagram of the cross-sectional structure of a developing graphic plate formed by processing in accordance with an embodiment of the present invention; Figure 3 A schematic diagram of a first planar structure of a developing graphic plate formed by processing according to an embodiment of the present invention; Figure 4A schematic diagram of a second planar structure of a developing graphic plate formed by processing according to an embodiment of the present invention; Figure 5 A schematic diagram of the cross-sectional structure of an etched graphic plate formed by processing according to an embodiment of the present invention; Figure 6 A schematic diagram of the cross-sectional structure of a circuit board to be polished formed by processing according to an embodiment of the present invention; Figure 7 A schematic diagram of the cross-sectional structure of a circuit board with a sloped copper layer formed by processing according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the cross-sectional structure of a circuit board with a sloped copper layer to be etched with a dry film attached according to an embodiment of the present invention; Fig. 9 A schematic diagram of the planar structure of a sloped circuit board formed by processing in accordance with an embodiment of the present invention; Fig.10 A schematic diagram of the planar structure of a dry film enclosed pattern circuit board formed by processing according to an embodiment of the present invention; Fig.11 This is a schematic diagram of the planar structure of the first screen printing solder resist ink according to an embodiment of the present invention; Fig.12 A schematic diagram of the planar structure of a circuit board having a first solder resist layer formed by processing according to an embodiment of the present invention; Fig.13 A schematic diagram of the planar structure of a circuit board formed with a solder mask layer in accordance with an embodiment of the present invention; Fig.14 A schematic diagram of the planar structure of a circuit board processed to form a thick copper slope circuit according to an embodiment of the present invention; Fig.15 The cross-sectional structure diagram of a circuit board processed to form a thick copper slope circuit according to an embodiment of the present invention.

[0024] Description of Figure Numbers: Label name Label name 10 Developing Graphics Board 2111 Independent Geometry 100 Thick copper clad laminate 2111A Circular graphics 110 Thick copper layer 2111B Isosceles trapezoid 1110A Thick copper circuit to be processed 20 Etched Graphics Board 1120A Slope line to be processed 30 Circuit board to be polished 1130A Thin copper lines to be processed 40 Slope copper layer circuit board 1110B Thick copper circuit layer 300 Graphic dry film layer 1120B Slope line copper layer 400 Second dry film pattern 1130B Thin copper circuit copper layer 50 Slope circuit board 1110C Thick copper circuit 60 Dry film encloses graphic circuit boards 1120C Slope line 510 First solder mask 1130C Thin copper lines 5110 First ink layer 1120E Matrix Etched Graphics 520 Second solder mask layer 120 Insulation dielectric layer 70 First solder mask circuit board 200 First dry film layer 80 Solder mask circuit board 210 Matrix development graphics 90 Thick copper slope circuit board 2110 Development array 500 Surface treatment layer The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0028] See also Figure 1 ; Figure 1 The present invention is a process flow chart of a manufacturing method according to an embodiment of the present invention.

[0029] The method for manufacturing a circuit board with a thick copper slope circuit provided in an embodiment of the present invention comprises a thick copper circuit 1110C, a slope circuit 1120C, and a thin copper circuit 1130C connected in series. The circuit board with a thick copper slope circuit is manufactured according to Figure 1 It is made through the processing process. Please refer to the following for the specific processing method.

[0030] Step S10: Take a thick copper clad laminate 100 and attach a first dry film layer 200 on the thick copper layer 110 of the thick copper clad laminate 100; the thick copper clad laminate 100 is a laminated structure of a thick copper layer 110 and an insulating dielectric layer 120. The first dry film layer 200 is attached in a general dry film attaching manner to prepare a dry film foundation for subsequent pattern transfer processing.

[0031] See also Figure 2 ; Figure 2 It is a schematic diagram of the cross-sectional structure of a developing graphic plate processed and formed according to an embodiment of the present invention.

[0032] Step S20: The first dry film layer 200 is sequentially exposed and developed, the first dry film layer 200 covering the thick copper circuit 1110A to be processed is retained, the first dry film layer 200 on the slope circuit 1120A to be processed is developed to form a matrix development pattern 210, and the first dry film layer 200 covering the thin copper circuit 1130A to be processed is developed to form a development pattern board 10.

[0033] In this step, the first dry film layer 200 is used to differentiate the dry film layers of three different areas, namely, the thick copper circuit 1110A to be processed, the slope circuit 1120A to be processed, and the thin copper circuit 1130A to be processed, according to the etching requirements. That is, the first dry film layer 200 covering the thick copper circuit 1110A to be processed is completely exposed so that it is not developed; the first dry film layer 200 of the slope circuit 1120A to be processed is patterned, exposed according to the shape of the pattern, and developed; the first dry film layer 200 covering the thin copper circuit 1130A to be processed is not exposed so that it is completely developed; and a pattern basis of the dry film layer in different regions is provided for subsequent etching processing.

[0034] In this embodiment, the matrix developing pattern 210 is composed of a number of single-row developing geometric figures regularly arranged in the developing area; the single-row developing geometric figure is a developing array 2110 including one or more independent geometric figures 2111; the developing size of the developing array 2110 is arranged to increase from small to large from one end of the thick copper circuit 1110 to be processed to one end of the thin copper circuit 1130 to be processed.

[0035] See also Figure 3 ; Figure 3 It is a schematic diagram of the first planar structure of a developed graphic plate formed by processing in an embodiment of the present invention.

[0036] Based on the above-mentioned matrix development pattern 210, in one embodiment, the independent geometric figures 2111 constituting the matrix development pattern 210 are circular figures 2111A, and the circular figures 2111A are arranged from small to large from the thick copper line 1110A area to be processed to the thin copper line 1130A area to be processed, and the circular diameter of the circular figure 2111A at the small end is 0.015mm to 0.05mm, and the circular diameter of the circular figure 2111A at the large end is 0.05mm to 0.125mm.

[0037] The circular pattern 2111A is used to form a developing array 2110, and the developing array is further formed into a matrix developing pattern 210. The formation of the circular pattern 2111A is the dry film layer that is not exposed and developed during the above-mentioned developing process. The diameter of the area close to the thick copper circuit 1110A to be processed is smaller, while the diameter of the area close to the thin copper circuit 1130A to be processed is larger. When the etching process is subsequently performed, under the same etching conditions, the flow rate of etching solution through the circular pattern 2111A with a smaller diameter and the exchange amount of etching solution are smaller than those of the circular pattern 2111A with a larger diameter, so that the etching amount of the thick copper layer 110 corresponding to the smaller diameter is smaller than the etching amount of the thick copper layer 110 corresponding to the larger diameter. That is, the developing pattern is used to form a differentiated etching amount effect on the copper layer of the same thickness, so that the etching hole formed in the thick copper layer 100 under the smaller circular pattern 2111A is shallower, while the etching hole formed in the thick copper layer 100 under the larger circular pattern 2111A is deeper, providing a copper surface foundation with different etching depths for subsequent polishing.

[0038] See also Figure 4 ; Figure 4 It is a schematic diagram of the second planar structure of the developed graphic plate formed by processing according to an embodiment of the present invention.

[0039] Based on the above-mentioned matrix development pattern 210, in one embodiment, the independent geometric figures 2111 constituting the matrix development pattern 210 are isosceles trapezoidal figures 2111B; the single-row development geometric figures are development arrays including one isosceles trapezoidal figure; the short side width of the isosceles trapezoid is 0.015 mm to 0.05 mm, and the long side width of the isosceles trapezoid is 0.05 mm to 0.125 mm.

[0040] The principle of using the isosceles trapezoidal figure 2111B is the same as the principle of using the circular figure 2111A described above.

[0041] However, the isosceles trapezoidal figure 2111B is a larger groove-shaped structure, so a larger amount of liquid is exchanged through it during the etching process. Therefore, in one embodiment, the two waist sides of the isosceles trapezoidal figure 2111B are arc-shaped sides.

[0042] The arcuate edge can be designed to be a relatively inwardly concave curved edge, that is, the isosceles trapezoidal figure 2111B has a non-uniform transition from the short side to the long side. In this way, the flow rate and exchange amount in the isosceles trapezoidal figure 2111B become smaller during the exchange of the solution, and the flow direction is hindered to a certain extent, so that the etching effect in the vertical direction is better, preventing the thick copper layer 110 from being over-etched, resulting in the slope line copper layer being not smooth enough.

[0043] It is worth noting that, in addition to the above two matrix development patterns 210 provided in this embodiment, other matrix development patterns 210 may also be used, such as: triangular or mesh patterns; which can be determined according to the copper thickness of the thick copper layer and the etching effect formed during the etching process.

[0044] See also Figure 5 and Figure 6 ; Figure 5 A schematic diagram of the cross-sectional structure of an etched graphic plate formed by processing according to an embodiment of the present invention; Figure 6 It is a schematic diagram of the cross-sectional structure of a circuit board to be polished formed by processing according to an embodiment of the present invention.

[0045] Step S30: Etching is performed to form a matrix etching pattern 1120E in the slope circuit 1120A area to be processed, forming an etching pattern plate 20, and then film stripping is performed to form a circuit board 30 to be polished.

[0046] After etching, the slope circuit 1120A to be processed forms a matrix etching pattern 1120E, the thin copper circuit 1130A to be processed forms a thin copper circuit copper layer 1130B, and the thick copper circuit 1110A to be processed forms a thick copper circuit copper layer 1110B. In fact, the thick copper circuit 1110A to be processed is covered with a dry film layer and is not etched, so its shape remains unchanged.

[0047] The slope circuit 1120A region to be processed is etched according to the etching parameters for directly etching the thin copper circuit copper layer 1130B to ensure that the thin copper circuit 1130A to be processed can be etched to form the thin copper circuit copper layer 1130B. Under this premise, the layout and size of the matrix development pattern 210 are designed and tested so that the slope circuit 1120A to be processed can be etched to form the matrix etching pattern 1120E, and the depth of the matrix etching pattern 1120E gradually deepens from the thick copper circuit 1110A to be processed to the thin copper circuit 1130A region to be processed.

[0048] See also Figure 7 , Figure 7 It is a schematic diagram of the cross-sectional structure of a circuit board with a sloped copper layer formed by processing according to an embodiment of the present invention.

[0049] Step S40: The matrix etching pattern 1120E is polished and removed to form the slope copper layer circuit board 40.

[0050] The grinding process is performed using a sanding belt grinding plate; the sanding belt grinding plate is used to grind the matrix etching pattern 1120E by adjusting the grinding pressure of the sanding belt grinding plate and the height of the sanding belt distance and the contour of the slope circuit copper layer 1120B according to the slope shape of the slope circuit copper layer 1120B; after grinding, the matrix etching pattern 1120E forms a slope circuit copper layer 1120B.

[0051] Generally, a sanding belt is used for grinding, and the grinding pressure is adjusted so that when the sanding belt is grinding to the area where the matrix etching pattern 1120E is not made, its pressure value will not grind the circuit. The reason is that after the sanding belt grinding pressure is adjusted, the sanding belt grinding roller can distinguish different areas through pressure by contacting the copper surface. The area where the matrix etching pattern 1120E is not made, that is, the area of ​​the thick copper circuit copper layer 1110B and the area of ​​the thin copper circuit copper layer 1130B, the copper layer on the surface is a complete copper layer in the plane direction in contact with the sanding belt. If necessary Grinding requires greater pressure, and the copper layer of the matrix etched pattern 1120E is an incomplete copper layer in the plane direction in contact with the sanding belt. The grinding pressure required is relatively small compared to the complete copper layer, so it can play a grinding role and effect; therefore, in combination with the above-mentioned production process, the matrix etched pattern 1120E is made first and then polished, so that the polishing has regional differentiation characteristics and realizes the polishing of slope lines, rather than directly polishing the thick copper layer 110 to form a slope. Otherwise, the problem of excessive grinding force causing excessive expansion and contraction or tearing of the board surface will occur.

[0052] In one embodiment, the starting point and the ending point of the belt grinding can also be adjusted through the testing and the program of the belt grinding equipment, and the sanding belt can be gradually raised in the process of grinding from the thin copper circuit copper layer 1130B area to the thick copper circuit copper layer 1110B area according to the slope angle of the slope circuit copper layer 1120B area, and the grinding position can be coordinated with the grinding pressure to grind the matrix etching pattern 1120E.

[0053] See also Figure 8 and Fig. 9 ; Figure 8 This is a schematic diagram of the cross-sectional structure of a circuit board with a sloped copper layer to be etched with a dry film attached according to an embodiment of the present invention; Fig. 9 It is a schematic diagram of the planar structure of a sloped circuit board processed and formed according to an embodiment of the present invention.

[0054] Step S50: The circuit pattern transfer process is performed to form a slope circuit board 50.

[0055] That is, the circuit pattern transfer processing method of attaching the pattern dry film layer 300, exposing, developing, etching, and stripping is adopted to form the circuit pattern slope circuit board 50.

[0056] The thick copper circuit copper layer 1110B is processed to form a thick copper circuit 1110C, the slope circuit copper layer 1120B is processed to form a slope circuit 1120C, and the thin copper circuit copper layer 1130B is processed to form a thin copper circuit 1130C. The schematic diagram of the cross-sectional structure of the slope circuit board 50 is not drawn, and can be referred to Figure 7 understand.

[0057] See also Fig.10 ; Fig.10 The schematic diagram of the planar structure of a dry film enclosed pattern circuit board formed by processing according to an embodiment of the present invention.

[0058] Step S60: A second dry film layer 300 is applied to the slope circuit board, and exposure and development are performed in sequence to form a second dry film pattern 400 . The second dry film pattern 400 covers the periphery of the entire slope circuit 1120C to form a dry film enclosed pattern circuit board 60 .

[0059] The second dry film pattern 400 area encloses the slope circuit 1120C within the pattern area formed by the dry film pattern, and extends a certain distance toward the area of ​​the thick copper circuit 1110C and the area of ​​the thin copper circuit 1130C, with a single-side extension of 0.1 mm to 2.0 mm.

[0060] The enclosed area can provide an ink barrier when the first silk-screen ink is subsequently produced, preventing the ink from excessively diffusing and extending to adjacent areas. On the one hand, the enclosed area can completely cover the entire slope line 1120C range. On the other hand, it can provide a dimensional basis for the subsequent production of the second solder resist layer 520 to be pressed on the first solder resist layer 510, making the ink coverage more comprehensive and more secure.

[0061] See also Fig.11 and Fig.12 ; Fig.11 This is a schematic diagram of the planar structure of the first screen printing solder resist ink according to an embodiment of the present invention; Fig.12 The diagram is a planar structural diagram of a circuit board having a first solder resist layer formed thereon according to an embodiment of the present invention.

[0062] Step S70: The first ink layer 5110 is screen-printed in the area covered by the second dry film pattern 400, and the first pre-bake, the first development, the first post-curing bake, and the dry film are sequentially performed to form the first solder resist layer 510, thereby forming a first solder resist layer circuit board 70 as a whole.

[0063] The second dry film pattern 400 is used to form an enclosed area, so that the ink will not exceed the range of the enclosed area when the first ink layer 5110 is screen-printed, that is, the ink completely covers the area of ​​the slope line 1120C, effectively preventing the ink from flowing downstream due to the slope of the slope line, and preventing the ink from excessively diffusing and losing so that the ink at the thicker end of the slope line is too thin, that is, the enclosed area provides effective regional blocking for the screen-printed first ink layer 5110, thereby providing a better processing effect.

[0064] See also Fig.13 , Fig.13 The schematic diagram of the planar structure of a circuit board with a solder mask layer formed according to an embodiment of the present invention is shown.

[0065] Step S80: A second solder resist layer 520 is formed on the first solder resist layer circuit board, and the second solder resist layer 520 covers the area where the solder resist layer needs to be formed except the first solder resist layer 510 , so as to form a solder resist layer circuit board 80 .

[0066] This step is to pre-process the circuit board after the first solder resist layer 510 is made. According to the requirements of the solder resist pattern data in the circuit board design data, a second solder resist layer 520 is made for other areas that need to be made of solder resist except the area covered by the first solder resist layer 510, and a second pre-bake, a second development, and a second post-curing bake are performed in sequence.

[0067] The second solder resist layer 520 partially covers the first solder resist layer 510 , with a coverage depth of 0.05 mm to 0.2 mm, thereby achieving the effect of complete coverage of the ink and ensuring the reliability of ink production.

[0068] See also Fig.14 and Fig.15 , Fig.14 A schematic diagram of the planar structure of a circuit board processed to form a thick copper slope circuit according to an embodiment of the present invention; Fig.15 The cross-sectional structure diagram of a circuit board processed to form a thick copper slope circuit according to an embodiment of the present invention.

[0069] Step S90: The solder resist layer circuit board 80 is post-processed to form a circuit board 90 with thick copper slope lines.

[0070] That is, the circuit board on which the second solder resist layer 520 is manufactured is subjected to surface treatment to form a surface treatment layer, and is subjected to molding and other necessary processing to form a sloped circuit board.

[0071] It can be seen that the circuit board 90 with thick copper slope circuits processed by this embodiment adopts chemical processing such as developing graphic design, developing processing, and etching processing as the main method, and physical processing such as grinding as the auxiliary method, which effectively improves the processing accuracy of the slope circuits and greatly reduces the problem of excessive expansion and contraction or even tearing of the board surface caused by physical and mechanical processing; the solder mask layer processing of the slope circuit forms a solder mask effect with good comprehensive coverage, good thickness, and high precision through the design of the dry film enclosed area and the design and processing of the first solder mask layer and the second solder mask layer; the overall processing process can produce a circuit board with thick copper slope circuits with high precision and high reliability.

[0072] It should be noted that due to the different designs, processing, and application scenarios of circuit boards during the actual processing and application processes, the drawings of this embodiment are only schematic diagrams for illustrating the implementation process of the embodiment, and do not represent the size ratios of the actual products, nor do they represent figures that are enlarged in proportion according to actual conditions.

[0073] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a circuit board with a thick copper slope circuit, wherein the thick copper slope circuit is composed of a thick copper circuit, a slope circuit, and a thin copper circuit in series; It is characterized in that The production method comprises the following steps: S10: taking a thick copper clad laminate, and attaching a first dry film layer on the thick copper layer of the thick copper clad laminate; S20: sequentially exposing and developing the first dry film layer, retaining the first dry film layer covering the thick copper circuit to be processed, developing the first dry film layer covering the thin copper circuit to be processed, and developing the first dry film layer on the slope circuit to be processed to form a matrix development pattern; S30: performing etching processing to form a matrix etching pattern in the slope circuit area to be processed, and then performing film stripping processing; S40: performing a grinding process to grind away the matrix etching pattern; S50: performing circuit pattern transfer processing to form a slope circuit pattern plate; S60: attaching a second dry film layer to the slope circuit pattern board, and sequentially exposing and developing to form a second dry film pattern, wherein the second dry film pattern covers the periphery of the entire slope circuit area to form a dry film enclosed pattern circuit board; S70: performing a first screen printing of solder mask ink in the area covered by the second dry film pattern, and performing a first pre-bake, a first development, a first post-curing bake, and a dry film removal in sequence to form a first solder mask layer, thereby forming a first solder mask layer circuit board as a whole; S80: forming a second solder resist layer on the first solder resist layer circuit board, wherein the second solder resist layer covers the area where the solder resist layer needs to be formed except the first solder resist layer, to form a solder resist layer circuit board; S90: performing post-processing on the solder mask circuit board to form the circuit board with the thick copper slope circuit.

2. A method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 1, characterized in that: The matrix development pattern is composed of a number of single-row development geometric patterns regularly arranged in the development area; The single-row development geometry is a development array comprising one or more independent geometric patterns; The developing size of the developing array is set to increase from smaller to larger from one end of the thick copper circuit to be processed to one end of the thin copper circuit to be processed.

3. A method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 2, characterized in that: The independent geometric figure is a circular figure; The single-row development geometric figure is a development array including more than or equal to 2 independent circular figures.

4. A method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 3, characterized in that: The diameter of the smaller circular figure is 0.015 mm to 0.05 mm, and the diameter of the larger circular figure is 0.05 mm to 0.125 mm.

5. The method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 2, characterized in that: The independent geometric figure is an isosceles trapezoid figure; The single-row development geometric figure is a development array including one of the isosceles trapezoidal figures.

6. A method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 5, characterized in that: The width of the short side of the isosceles trapezoidal figure is 0.015 mm to 0.05 mm, and the width of the long side of the isosceles trapezoidal figure is 0.05 mm to 0.125 mm.

7. A method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 5, characterized in that: The two waist sides of the isosceles trapezoidal figure are arc-shaped sides.

8. The method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 1, characterized in that: The grinding process is performed by using a sand belt grinding plate; The sanding belt grinding plate is used to grind the matrix etching pattern by adjusting the grinding pressure of the sanding belt grinding plate and the distance between the sanding belt and the height of the slope line according to the slope shape of the slope line.

9. The method for manufacturing a circuit board with a thick copper slope circuit as claimed in claim 1, characterized in that: The area of ​​the dry film enclosed pattern extends unilaterally toward the area of ​​the thick copper circuit and the area of ​​the thin copper circuit by 0.1 mm to 2.0 mm.

10. The method for manufacturing a circuit board with thick copper slope circuit according to claim 1, characterized in that: The second solder resist layer partially covers the first solder resist layer.

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