Spraying and shielding etching line of printed circuit board (PCB)

Abstract

The utility model provides a spraying and shielding etching line for a PCB (Printed Circuit Board), comprising a spraying mechanism which comprises a plurality of spraying pipes which are arranged in parallel, and each spraying pipe is provided with a plurality of nozzles; the spraying mechanism can spray etching liquid to the PCB, and a non-right-angle included angle is formed between the length direction of a spraying pipe and the conveying direction of the PCB; nozzles are arranged above and below the PCB and respectively face the top surface and the bottom surface of the PCB; droplet areas sprayed by the adjacent spray pipes are overlapped with each other; the shielding plate is arranged between the spraying mechanism and the PCB, the shielding plate comprises a hollow hole, the etching liquid can penetrate through the hollow hole, and the part, outside the hollow hole, of the shielding plate can prevent the etching liquid from reaching the PCB. Therefore, uniform etching of the etching liquid is ensured by refining and enriching the spraying mechanism, and the shielding plate is used for selectively blocking the etching liquid, so that the phenomenon of uneven etching is further eliminated.

Description

Technical Field

[0001] This application relates to the field of printed circuit board manufacturing, and particularly to an etching line for spraying and masking of a PCB board. Background Art

[0002] In the field of printed circuit board processing, there are ordinary electroplating etching processes, additive processes, and semi-additive processes. Due to the simple process and cost advantages, the electroplating etching process is currently the main processing method for rigid PCB boards.

[0003] As more and more functional chips need to be connected on the PCB board, the patterns per unit area are increasing, and the patterns are becoming more and more delicate. To correspond to finer circuits and improve the product yield, the process needs to be improved. One of them is to improve the uniformity of spray etching of the PCB board.

[0004] The Chinese invention patent with the publication number "CN103187222B" discloses "a spray head and a semiconductor processing device". The spray head includes: an injection plate with a plurality of injection holes therein; and a plurality of shielding units, each shielding unit controlling the shielding degree of a corresponding injection hole. Among them, each shielding unit includes a shielding plate and an actuator connected to the shielding plate. The spray head and the semiconductor processing device can in-situ control the processing gas condition. This invention patent gives each injection hole the freedom of opening and closing adjustment, which to a certain extent improves the uniformity of spray etching. However, the field of printed circuit board processing still needs more diverse, better, and more practical technologies. Summary of the Utility Model

[0005] In view of the state of the above-mentioned prior art, this application is made. The purpose of this application is to provide an etching line for spraying and masking of a PCB board.

[0006] The technical solutions adopted by this application to solve its technical problems include: an etching line for spraying and masking of a PCB board, including: a spraying mechanism, including a plurality of spray pipes arranged in parallel with each other, and a plurality of nozzles are provided on each spray pipe; the spraying mechanism can spray etching solution on the PCB board, and the length direction of the spray pipe forms a non-right angle with the conveying direction of the PCB board; nozzles are provided above and below the PCB board, and are respectively oriented towards the top surface and the bottom surface of the PCB board; the droplet areas ejected by adjacent spray pipes overlap each other; a shielding plate is provided between the spraying mechanism and the PCB board, the shielding plate includes hollowed-out holes, the hollowed-out holes can allow the etching solution to pass through, and the part of the shielding plate outside the hollowed-out holes can block the etching solution from reaching the PCB board.

[0007] As a further improvement of the present application, the spraying mechanism and the shielding plate are distributed in a plurality of etching chambers, and the PCB board is conveyed horizontally and passes through a plurality of the etching chambers.

[0008] As a further improvement of the present application, the spacing between the nozzles on each spray pipe is adjustable; the height of the nozzles from the PCB board is adjustable; the spraying pressure of the nozzles is adjustable.

[0009] As a further improvement of the present application, the lateral spacing between the two ends of the same spray pipe in the lateral direction perpendicular to the conveying direction of the PCB board is equal to the lateral spacing between adjacent two spray pipes.

[0010] As a further improvement of the present application, the number of nozzles on each spray pipe is equal, and the nozzles on the same spray pipe are arranged at equal intervals.

[0011] As a further improvement of the present application, the space occupied by the droplet area ejected by the nozzles is a cone, and there is an overlap between adjacent two droplet areas of the same spray pipe, and there is also an overlap between adjacent two droplet areas of adjacent two spray pipes.

[0012] As a further improvement of the present application, the shielding plate is a resin plate with a thickness of more than 1.0 mm.

[0013] As a further improvement of the present application, the PCB board is a copper-clad bare board.

[0014] As a further improvement of the present application, the PCB board is a copper-clad board with a copper layer thickness of 70 μm.

[0015] As a further improvement of the present application, a thickness gauge is further provided downstream of the etching chamber at the most downstream end in the conveying direction of the PCB board, and the thickness gauge can measure the conductor thickness of the PCB board.

[0016] The beneficial effects of the etching line for spraying and shielding of the PCB board of the present application include: First, by refining and enriching the design of the spraying mechanism, spray pipes are provided both above and below the PCB board, and the spray pipes are arranged in rows obliquely and parallelly, and there is a certain overlap in the droplet area, so that the linearly conveyed PCB passes through a relatively more uniform etching solution, thereby ensuring the uniformity of etching. Second, a shielding plate is added, and the shielding plate is in a form of targeted local selective shielding. In actual use, the areas with strong original etching ability are shielded, so as to reduce the etching ability at the corresponding positions, and then improve the overall uniformity of etching, reduce defects such as etching deficiency and residual copper caused by uneven etching, further improve the ability to process etching patterns, and then improve the etching ability to process finer circuits. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a spraying mechanism of an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0019] Figure 2 It is a schematic structural diagram of a spraying mechanism of an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0020] Figure 3 It is a schematic application diagram of an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0021] Figure 4 It is a schematic structural diagram of a masking plate of an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0022] Figure 5 It is an effect diagram of etching without using a masking plate in an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0023] Figure 6 It is an effect diagram of etching using a masking plate in an embodiment of the spraying and masking etching line of the PCB board of the present application;

[0024] Figure 7 It is a process flow diagram of electroplating etching of an embodiment of the spraying and masking etching line of the PCB board of the present application.

[0025] Explanation of reference numerals

[0026] 1 - spray pipe; 2 - nozzle; 3 - droplet area; 4 - PCB board; 5 - masking plate; 51 - hollowed-out hole; 52 - blocking area; 6 - blind hole; 7 - chemical copper layer; 8 - electroplated copper layer; 9 - developing film; 10 - exposure area; 11 - etching tank; A - spray pipe spacing; B - spraying coverage area; C - area with strong etching ability. Detailed implementation manners

[0027] The exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, rather than to exhaust all feasible ways of the present application, nor to limit the scope of the present application.

[0028] Refer to Figures 1 to 4, embodiments of the present application provide an etching line for spraying and masking a PCB board. The etching line for spraying and masking a PCB board includes a spraying mechanism and a masking plate 5. The spraying mechanism includes a plurality of spray pipes 1 arranged in parallel with each other, and a plurality of nozzles 2 are arranged on each spray pipe 1; the spraying mechanism can spray etching solution on the PCB board 4. As Figure 3 shown, the length direction of the spray pipe 1 forms a non-right angle with the conveying direction of the PCB board 4. As Figure 2 shown, there is an overlap between the droplet areas 3 ejected from adjacent spray pipes 1. And nozzles 2 are provided above and below the PCB board 4 ( Figure 2 is a horizontal view, Figure 2 taking the nozzles 2 above the PCB board 4 as an example to show), the nozzles 2 above and below face the top surface and the bottom surface of the PCB board 4 respectively. The masking plate 5 is arranged between the spraying mechanism and the PCB board 4. As Figure 4 shown, the masking plate 5 includes a hollowed-out hole 51, and the hollowed-out hole 51 can allow the etching solution to pass through. The part outside the hollowed-out hole 51 of the masking plate 5 is a blocking area 52, and the blocking area 52 can block the etching solution.

[0029] In another embodiment, the etching line for spraying and masking a PCB board includes a plurality of etching chambers, and each etching chamber has a spraying mechanism and a masking plate 5. The PCB board 4 is conveyed horizontally and passes through these etching chambers. As Figure 3 shown, Figure 3 more Figure 1 shows the PCB board 4, and uses a dotted arrow to show the conveying direction of the PCB board 4. During the flow (that is, during the conveying process of the PCB board 4), the PCB board 4 is etched. In theory, under the state of uniform spraying at each position, an ideal uniform etching effect can be obtained. In order to improve the installation stability of the masking plate 5, the masking plate 5 can be connected with a fixing frame, and the fixing frame prevents the masking plate 5 from shaking or falling off in the etching chamber.

[0030] In another embodiment, the spacing between the nozzles 2 on the spray pipe 1 is adjustable; the height of the nozzle 2 from the PCB board 4 is adjustable; the spraying pressure of the nozzle 2 is also adjustable. After adjusting the spacing, height, and spraying pressure of the nozzle 1, that is, by increasing the spraying pressure at the position with weak etching ability, increasing the spraying flow rate and the impact force of the etching solution, and making fine adjustments to the height, orientation angle, etc. of the nozzle, ensure that the nozzle 2 is installed in the best state. The sprayed etching solution will evenly reach the surface of the PCB board 4, and the in-plane deviation can reach a level of 1 um. In actual applications, due to various reasons such as the processing accuracy and installation accuracy of the equipment, the in-plane etching uniformity may not be very ideal. If a better state is desired, further improvement is needed. For example, if the etching amount of all etching chambers is 70 um and a total of 36 rows of nozzles 2 are used for spraying, then the contribution of each row of nozzles 2 to the etching amount is 2 um. The position with strong etching ability etches 4 um more than the normal position, and the corresponding position needs to mask two rows of nozzles 2.

[0031] In another embodiment, the lateral spacing between the two ends of the same nozzle 1 in the lateral direction perpendicular to the conveying direction of the PCB board 4 is equal to the lateral spacing between adjacent nozzles 1. As Figure 1 shown, the nozzle spacing A is the lateral spacing between adjacent nozzles 1, and the number of nozzles 2 on each nozzle 1 is equal, and the nozzles 2 on the same nozzle 1 are arranged at equal intervals.

[0032] In another embodiment, the space occupied by the droplet region 3 ejected by the nozzle 1 is a cone, as Figure 2 shown, there is an overlap between two adjacent droplet regions 3 of the same nozzle 1, and there is also an overlap between the adjacent droplet regions 3 of two adjacent nozzles 1. The droplet region 3 of each cone finally falls on the PCB board 4, which is Figure 2 the spray coverage area B shown. Specifically, regarding the degree of overlap of the droplet regions 3, the edge of a certain spray coverage area B may be close to the edge of the spray coverage area B of a nozzle 1 separated by one nozzle. From a top view perspective, that is, the two spray coverage areas B are similar to the effect of two circles approaching to almost being externally tangent. This enables the PCB board 4 to be covered with a double spray coverage area B as much as possible, which is also beneficial to improving the overall uniformity of the spray.

[0033] In another embodiment, the PCB board 4 can be a copper-clad bare board. The thickness of the copper layer of the copper-clad bare board can be 70 μm. A thickness gauge is also provided downstream of the etching chamber at the most downstream in the conveying direction of the copper-clad bare board, and the thickness gauge can measure the thickness of the conductor (i.e., the copper layer) in the copper-clad bare board. The copper-clad bare board with a thickness of 70 μm is circulated in each etching chamber, and at the same time, the masking plate 5 is not used. After full etching, the thickness gauge is used to measure the copper thickness of the copper-clad bare board to clarify the remaining amount of the conductor thickness in the plane of the copper-clad bare board, so as to understand the etching uniformity of each part. Then, the overall uniformity is analyzed using a graph to clarify the parts with a thick conductor (large remaining amount) and the parts with a thin conductor (small remaining amount). The part with a thin conductor is the etching-capable strong region C as Figure 5 shown in the example.

[0034] The etching-capable strong region C is further marked, and the marking content includes three parameters: the coordinate position of the etching-capable strong region C on the PCB board 4, the width of the etching-capable strong region C, and the etching amount that the etching-capable strong region C has more than the normal etching region.

[0035] The spraying mechanism can be a vacuum spraying system. The vacuum spraying system can evacuate the spraying chamber to a high vacuum state to ensure that the PCB board 4 is clean and free of impurities. The vacuum spraying system includes vacuum components such as a vacuum pump required by itself. The masking plate 5 is designed in combination with the size of the vacuum components of the spraying mechanism, the position, width, and depth of the etching-capable strong region C. The position to be masked is designed based on the predicted position and width, and the number of nozzles 2 to be masked is designed based on the predicted etching ability.

[0036] Calculation method for the number of masks: Estimate the overall etching amount and the number of rows of the etching chamber nozzles 1, calculate the etching amount of a single nozzle 1, and calculate the number of additional masks at different positions based on the difference in etching capabilities at different etching amount positions.

[0037] After designing the relevant positions and dimensions, according to the equipment itself, a routing machine or a special milling machine can be used to mill off the excess board edges and process the corresponding patterns. Resin boards with a thickness of more than 1.0 mm can be used. Resin boards with a thickness of more than 1.0 mm can effectively resist the erosion of the etching solution and can also be used for a long time under high-temperature conditions.

[0038] During actual operation, the mask plate 5 is installed on the equipment, and the flow of the etching chamber is carried out again using a 70-μm copper-clad light board. After etching, the same test is carried out again using a conductor thickness measuring instrument, and the etching uniformity is measured and analyzed using the completed data to confirm whether the improvement effect is achieved. If there are still deviations, the mask plate can be redesigned and installed and debugged again based on the completion of this measurement.

[0039] Such as Figure 5 and Figure 6 The effect diagram examples of Figure 5 Figure 17 is the etching uniformity effect diagram of the copper-clad light board without using the mask plate 5, in which there are several obvious areas C with strong etching capabilities, and the uniformity deviation is 1.17 μm. Figure 6 Figure 19 is the etching uniformity effect diagram of the copper-clad light board after using the mask plate 5. Compared with Figure 5 the etching amount has become significantly more uniform, and the uniformity deviation is 0.6 μm. Among them, Figure 5 and Figure 6 the units of 21.00, 19.00, 17.00, and 15.00 on the vertical axis are all μm. The evaluation of etching uniformity can be to evenly take 120 points of 12 by 10 on the specified surface, measure the conductor thickness at these 120 points, and calculate the deviation value based on these 120 measurement results.

[0040] Due to reasons such as the deterioration of the equipment itself, the uniformity after etching tends to deteriorate. Subsequently, regular tests and adjustments can be carried out to ensure that the equipment has long-term stable high-uniformity processing capabilities.

[0041] Such as Figure 7As shown in the figure, the basic process of the PCB board 4 electroplating and etching process of the embodiment of the present application may include the following eight steps carried out in sequence: drilling, chemical copper plating, electroplating copper, laminating, pattern exposure, dry film development, pattern etching, and stripping film. Among them, the drilling step processes blind holes 6, the chemical copper plating step makes a layer of chemical copper layer 7 on the blind holes 6, the electroplating copper step lays another layer of electroplating copper layer 8 on the chemical copper layer 7, and the electroplating copper layer 8 also fills the blind holes 6 at the same time. Laminating lays another layer of developing film 9 on the electroplating copper layer 8, the pattern exposure step selects the exposure area 10, the dry film development step washes away the developing film 9 in the exposure area 10, and the pattern etching step etches the electroplating copper layer 8 and the chemical copper layer 7 at the corresponding position below the exposure area 10 to form an etching groove 11; the stripping film step is to strip off the developing film 9.

[0042] In the process of improving the fineness of the pattern, the general solution is to use a high-resolution dry film, reduce the thickness of the dry film, and improve the resolution of the exposure machine to improve the pattern precision. However, the high-resolution dry film and the high-resolution exposure machine will greatly increase the processing cost. Reducing the thickness of the dry film will increase the sensitivity to foreign objects and reduce the yield of the product.

[0043] In the present application, by effectively improving the uniformity of etching, the processing precision of the pattern can be effectively improved, the short-circuit problem caused by insufficient etching can be effectively reduced, and the cost will not increase accordingly.

[0044] The above embodiments are only used to illustrate the technical concept and characteristics of the present application, and their purpose is to enable those who are familiar with this technology to understand the content of the present application and implement it. It cannot be used to limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A spray and shield etching line for PCB boards, characterized in that: include: The spray mechanism comprises a plurality of spray pipes arranged in parallel with each other, each of the spray pipes being provided with a plurality of nozzles; the spray mechanism can spray etching liquid on the PCB board, and the length direction of the spray pipe forms a non-right angle with the conveying direction of the PCB board; the nozzles are provided above and below the PCB board, and are respectively directed toward the top surface and the bottom surface of the PCB board; the droplet areas sprayed by adjacent spray pipes overlap each other; A shielding plate is arranged between the spray mechanism and the PCB board, the shielding plate includes a hollow hole, the hollow hole can allow the etching liquid to pass through, and the portion of the shielding plate outside the hollow hole can prevent the etching liquid from reaching the PCB board.

2. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The spray mechanism and the shielding plate are distributed in a plurality of etching chambers, and the PCB board is transported in a horizontal direction and passes through a plurality of the etching chambers.

3. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The distance between the nozzles on the spray pipe is adjustable; the height of the nozzle from the PCB board is adjustable; and the spray pressure of the nozzle is adjustable.

4. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The lateral spacing between the two ends of the same nozzle in the lateral direction perpendicular to the conveying direction of the PCB board is equal to the lateral spacing between two adjacent nozzles.

5. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The number of the nozzles on each of the nozzles is equal, and the nozzles on the same nozzle are arranged at equal intervals.

6. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The space occupied by the droplet area sprayed by the nozzle is a cone, and two adjacent droplet areas of the same nozzle overlap, and two adjacent droplet areas of two adjacent nozzles also overlap.

7. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The shielding plate is a resin plate with a thickness of 1.0 mm or more.

8. The spray and shield etching line for PCB board according to claim 1, characterized in that: The PCB board is a copper-clad bare board.

9. The spray and shielding etching line for PCB board according to claim 1, characterized in that: The PCB board is a copper-clad board, and the copper layer thickness is 70um.

10. The spray and shielding etching line for PCB board according to claim 2, characterized in that: In the conveying direction of the PCB board, a thickness gauge is also provided downstream of the etching chamber located at the most downstream end, and the thickness gauge can measure the conductor thickness of the PCB board.

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