Method for manufacturing high-precision bonding pad circuit board through cooperation of materials and patterns

Abstract

The invention discloses a method for manufacturing a high-precision bonding pad circuit board by matching a material with a pattern, which comprises the following steps of: pre-enlarging the pattern of a bonding pad, carrying out surface treatment on the pattern of the bonding pad, carrying out first etching, forming a surface circuit, manufacturing solder resist ink on the whole surface, pre-baking, forming a semi-cured ink layer and taking a copper foil layer; the semi-cured ink layer is pressed on one side of the semi-cured ink layer, a copper foil pattern layer is formed according to a bonding pad pattern, then processing of removing the semi-cured ink layer is carried out, the semi-cured ink layer covering the surface of the bonding pad pattern is removed, then baking curing and third etching are carried out, and the high-precision bonding pad circuit board is formed; a bonding pad pattern is pre-enlarged, a basis is provided for manufacturing a pattern with a solder resist window smaller than that of the bonding pad, processing of a circuit pattern is formed through blocking of a surface treatment layer, processing of a surface solder resist pattern is formed through manufacturing of a copper foil pattern layer, and processing of a high-precision bonding pad pattern is formed, the whole processing flow is convenient and efficient, and the flow relevance is high.

Description

Technical Field

[0001] The present invention relates to the field of circuit board design and processing, and particularly to a method for manufacturing a high-precision pad circuit board by matching materials with patterns. Background Art

[0002] At present, some high-precision medical detection and analysis instruments are gradually developing towards portable applications to meet the requirements of efficient, convenient, and rapid response in medical detection, and can even achieve the effect of self-detection at home; for the test cards supporting such high-precision medical detection and analysis instruments, the built-in basic circuit board requires relatively high pad precision to ensure the data accuracy in the high-precision analysis process. Generally, the surface pads of the circuit board are realized by etching the circuit pattern and making the solder mask pattern, and the surface treatment method is adopted, that is, for the pads that need to be exposed, the solder mask opening treatment is carried out, and for the surfaces that do not need to be exposed, the solder mask layer is used to cover; therefore, when manufacturing the solder mask pattern (exposing the surface pads) of this type of high-precision pad circuit board, it is required to have high precision, accurate position, and small dimensional error.

[0003] At present, generally, the alignment and exposure precision are improved, and the influencing factors of the shrinkage and expansion of different exposure, development, electroplating copper, electroplating gold and other processes are repeatedly tested and verified to determine the best processing flow and processing parameters to improve the graphic processing precision of the pads.

[0004] However, on the one hand, this method still fails to solve the problem of high-precision pad processing from the technical essence itself. It only makes a large amount of exploration on the selection of the existing processing flow, processing equipment, and processing materials to improve the processing precision. Moreover, there are many influencing factors for the pad processing precision. A large number of tests and verifications will increase the workload, and the changes in the actual processing conditions will make the data more sensitive and the uncertainty increase, making it difficult to form a stable processing method; on the other hand, after the solder mask ink is made to form the solder mask pattern, side etching will occur, and the side etching degree at different positions is different. Therefore, the problem of uneven edges of the solder mask pattern in the microscopic state will occur, reducing the precision of the pads.

[0005] Based on the above background, a manufacturing method for improving the processing precision of high-precision pad circuit boards is needed. Summary of the Invention

[0006] The present invention aims to solve the problem of low pad precision in the manufacturing process of a circuit board with high-precision pads, and provides a method for manufacturing a high-precision pad circuit board by matching materials with patterns, including the following steps: S10: Take a copper clad laminate, design a circuit pattern for it, the circuit pattern includes a pad pattern, and pre-enlarge the pad pattern to form a pre-enlarged pad pattern; S20: Attach a first dry film to one side of the copper layer of the copper clad laminate, and successively perform exposure and development processes on the first dry film according to the circuit pattern to form a first dry film pattern. The parts removed by development are exposed to form the circuit pattern, including exposing the pre-large pad pattern, and the whole board forms a dry film pattern board. S30: Perform surface treatment on the dry film pattern board to form a surface treatment layer on the surface of the circuit pattern, and then strip the film, and the whole board forms a surface treatment board. S40: Perform the first etching on the surface treatment board, and the surface treatment layer corresponding area forms surface circuits, and the whole board forms a surface circuit board. S50: On one side of the surface circuits of the surface circuit board, apply solder mask ink over the entire surface and perform pre-baking, and the solder mask ink forms a semi-cured ink layer; the whole board forms an ink layer processing board. S60: Take a copper foil layer, press it on one side of the semi-cured ink layer, attach a second dry film to the surface of the copper foil layer, and successively perform exposure, development, and the second etching processes on the second dry film according to the pad pattern, and etch away the copper foil layer corresponding to the pad pattern, and the whole board forms an auxiliary pattern board. S70: Perform the process of stripping the semi-cured ink layer on the auxiliary pattern board to form a solder mask stripped board, and the semi-cured ink layer covering the surface of the pad pattern is stripped; then bake and cure the solder mask stripped board, and perform the third etching to etch away the remaining copper foil layer to form the high-precision pad circuit board.

[0007] Optionally, forming the dry film pattern board includes: attaching the first dry film to one side of the copper layer of the copper clad laminate, and successively performing exposure and development processes on the first dry film according to the pre-large pad pattern to form the first dry film pattern, and the parts removed by development expose the pre-large pad pattern, and the whole board forms the dry film pattern board; forming the surface circuit board includes: attaching a photosensitive dry film to one side of the surface treatment layer of the surface treatment board, successively performing exposure and development on the photosensitive dry film according to the circuit pattern, then performing the first etching, and then stripping the film, and the copper layer forms the surface circuits, and the whole board forms the surface circuit board.

[0008] Optionally, forming the ink layer processing board includes: preparing the solder mask ink, taking glue, adding the glue into the solder mask ink, stirring to form a composite ink system, applying the composite ink system to one side of the surface circuits of the surface circuit board, and performing pre-baking, and the solder mask ink forms a semi-cured ink layer; the whole board forms the ink layer processing board.

[0009] Optionally, the glue is epoxy resin glue or phenolic resin glue.

[0010] Optionally, the viscosity of the glue at a temperature of 25°C±5°C is 900mPa.s to 5000mPa.s.

[0011] Optionally, the pad pattern is pre-enlarged by 30 μm to 100 μm on a single side.

[0012] Optionally, the surface treatment is electroplating gold or nickel-gold surface treatment.

[0013] Optionally, the pre-baking is performed at a temperature of 75°C±5°C for 25 minutes to 50 minutes.

[0014] Optionally, the copper foil layer is a thin copper foil layer, and the thickness of the thin copper foil layer is 5 μm to 20 μm.

[0015] Optionally, removing the semi-cured ink layer is to subject the auxiliary graphic plate to a film removal processing line or a solder resist removal processing line for removal processing.

[0016] In the technical solution of the present invention, the pad pattern is pre-enlarged to form a pre-enlarged pad pattern, so as to prepare a pad pattern foundation for making a solder mask window smaller than the pad pattern; by adopting a reverse process, the solder mask ink is first made on the whole board to form a semi-cured ink layer, and then a copper foil layer is used to form a copper foil pattern layer, and as an auxiliary tool, the semi-cured ink layer is removed by using chemical solutions to form a solder mask pattern and expose the pad, thereby replacing the prior art with a forward process (first making solder mask ink, and then forming a solder mask pattern by exposure and development), avoiding the problem of solder mask side erosion, and forming a non-exposure and non-development graphic processing process, and using a higher-precision copper foil graphic layer as an auxiliary layer to limit the graphic area, which greatly improves the processing accuracy of the pad; the overall processing process forms a relatively convenient processing process through the coordination of dry film materials, solder mask ink materials, copper foil layer materials and other materials with the graphic processing process, and reduces the precision requirements for processing precision such as mutual reference alignment, improves operability, and each processing process has a strong correlation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 It is a schematic diagram of the cross-sectional structure of a high-precision pad circuit board in the prior art; Figure 2 It is a schematic diagram of the plane structure of a high-precision pad circuit board in the prior art; Figure 3 Process flow chart of high-precision pad circuit board processing according to an embodiment of the present invention; Figure 4 Schematic cross-sectional structure diagram of a dry film pattern board formed according to an embodiment of the present invention; Figure 5 Schematic cross-sectional structure diagram of a surface treatment board formed according to an embodiment of the present invention; Figure 6 Schematic cross-sectional structure diagram of a surface circuit board formed according to an embodiment of the present invention; Figure 7 Schematic cross-sectional structure diagram of an ink layer processing board formed according to an embodiment of the present invention; Figure 8 Schematic cross-sectional structure diagram of an auxiliary pattern board formed according to an embodiment of the present invention; Figure 9 Schematic cross-sectional structure diagram of a solder mask stripping board formed according to an embodiment of the present invention; Figure 10 Schematic cross-sectional structure diagram of a high-precision pad circuit board formed according to an embodiment of the present invention; Figure 11 is Figure 10 planar structure diagram of; Figure 12 Planar structure diagram of another dry film pattern board formed according to an embodiment of the present invention; Figure 13 Planar structure diagram of another surface circuit board formed according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the drawings: 110X, existing technology pad pattern; 210X, existing technology surface treatment layer; 610X, existing technology solder mask pattern; 6110X, existing technology solder mask side etching; 1020X, existing technology insulating dielectric layer; 10, dry film pattern board; 100, copper clad laminate; 110, pad pattern; 110Y, pre-large pad pattern; 1010, copper layer; 1020, insulating dielectric layer; 120, first dry film pattern; 20, surface treatment board; 210, surface treatment layer; 30, surface circuit board; 310, surface circuit; 40, ink layer processing board; 410, semi-cured ink layer; 50, auxiliary pattern board; 510, second dry film pattern; 520, copper foil pattern layer; 60, solder mask stripping board; 610, solder mask pattern; 70, high-precision pad circuit board; 10A, another dry film pattern board; 120A, photosensitive dry film pattern; 30A, another surface circuit board.

[0020] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0023] In addition, in the present invention, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0024] Please refer to Figure 1 and Figure 2 , Figure 1 which is a schematic cross-sectional structure diagram of a high-precision pad circuit board in the prior art; Figure 2 which is a schematic plan structure diagram of a high-precision pad circuit board in the prior art.

[0025] In the prior art, a prior art surface treatment layer 210X is made on the surface of the prior art pad pattern 110X, which is located between the prior art solder mask patterns 610X and is all made on the surface of the prior art insulating dielectric layer 1020X. That is, the prior art solder mask pattern 610X is formed by exposure and development of a solder mask ink layer. The prior art solder mask pattern 610X has a prior art solder mask side etch 6110X, which will affect the processing accuracy of the prior art solder mask pattern 610X itself, making the edges of the prior art pad pattern 110X uneven in the plane direction (please refer to Figure 2 ), affecting the use accuracy.

[0026] Please refer to Figure 3 , Figure 3 which is a process flow chart of the processing technology of a high-precision pad circuit board according to an embodiment of the present invention.

[0027] The manufacturing process of the embodiment of the present invention includes the process as shown in Figure 3 . For specific descriptions, please refer to the following text.

[0028] Please refer to Figure 4 , Figure 4 which is a schematic cross-sectional structure diagram of a dry film pattern board fabricated according to an embodiment of the present invention.

[0029] Step S10: Take a copper clad laminate 100, design a circuit pattern thereon, the circuit pattern including a pad pattern 110, pre-enlarge the pad pattern 110 to form a pre-enlarged pad pattern 110Y; the copper clad laminate 100 further includes an insulating dielectric layer 1020.

[0030] Since in the subsequent processing of this embodiment, a part of the pad pattern 110 needs to be fabricated under the solder mask pattern 610, therefore, by pre-enlarging the pad pattern 110 here, a precondition for fabricating the pad pattern 110 under the solder mask pattern 610 is formed.

[0031] In this embodiment, when pre-enlarging the pad pattern 110, the unilateral pre-enlargement is 30 μm to 100 μm.

[0032] According to the actual utilization area of the board surface, the minimum pre-enlarged size can be selected.

[0033] Step S20: Attach a first dry film to one side of the copper layer 1010 of the copper clad laminate 100, and sequentially perform exposure and development processing on the first dry film according to the circuit pattern to form a first dry film pattern 120. The parts removed by development are exposed to form a circuit pattern, including exposing the pre-enlarged pad pattern 110Y, and the whole board forms a dry film pattern board 10.

[0034] The fabricated dry film pattern board 10 serves as a board surface foundation for subsequent surface treatment and the first etching.

[0035] Optionally, forming the first dry film pattern 120 by performing exposure and development processing on the first dry film belongs to a conventional method.

[0036] Optionally, the first dry film is an anti-electroplating gold dry film, which matches the electroplating gold processing process if the subsequent surface treatment is electroplating gold.

[0037] Optionally, the thickness of the copper layer 1010 is relatively thin, being 5 μm to 20 μm. On the one hand, it meets the application requirements of the test card of the portable medical device, and on the other hand, it is beneficial to subsequent etching processing, forming a processing process of rapid etching and high-precision etching.

[0038] Please refer to Figure 5 , Figure 5 which is a schematic cross-sectional structure diagram of a surface treatment board fabricated according to an embodiment of the present invention.

[0039] Step S30: The surface of the dry film pattern board 10 is surface-treated to form a surface treatment layer 210 on the surface of the circuit pattern, and then the film is removed, and the whole board forms a surface treatment board 20.

[0040] In this embodiment, the surface treatment layer 210 is first fabricated. Under the protection of the surface treatment layer 210, the unprotected areas are subjected to film removal and etching to form the required circuit pattern. The reverse process of first fabricating the surface treatment layer 210 and then fabricating the circuit pattern is adopted. On the one hand, compared with the prior art method of fabricating the circuit pattern by the process of pasting dry film, exposing, developing, etching, and removing the film, and then fabricating the surface treatment layer 210 subsequently, the processing flow is shortened and the processing accuracy is improved. On the other hand, it can provide a basis for the difference conditions on the board surface for directly fabricating the solder resist ink on the front side subsequently, which is convenient for the subsequent processing of exposing the pad pattern by removing the semi-cured ink layer 410.

[0041] In this embodiment, the surface treatment is electroplated gold or immersion nickel gold surface treatment.

[0042] Both electroplated gold and immersion nickel gold can form a gold layer. The gold layer can withstand the etching of the subsequent processes and the impact of the film removal potion. In this embodiment, it can not only play the role of the dry film pattern, but also play the role of selectively protecting the copper surface. Among them, the gold layer of electroplated gold has a greater density, higher hardness, and a smoother surface. Therefore, electroplated gold processing is preferably used.

[0043] Please refer to Figure 6 , Figure 6 , which is a schematic cross-sectional structure diagram of the surface circuit board fabricated according to the embodiment of the present invention; Step S40: The surface treatment board 20 is subjected to the first etching, and the surface circuit 310 is formed in the area corresponding to the surface treatment layer 210, and the whole board forms a surface circuit board 30.

[0044] Following the above process, since the surface of the copper layer 1010 is divided into two areas after the film is removed, one is the area covered with the surface treatment layer 210, and the other is the exposed copper surface. During the first etching, since the surface treatment layer 210 is not etched by the etching potion, the copper layer 1010 in this area is protected to form the circuit pattern, while the exposed copper surface is etched away.

[0045] Corresponding to the above surface treatment, preferably electroplated gold or immersion nickel gold, the gold layer can better withstand the impact of the etching potion.

[0046] Please refer to Figure 7 , Figure 7 , which is a schematic cross-sectional structure diagram of the ink layer processing board fabricated according to the embodiment of the present invention.

[0047] Step S50: On one side of the surface circuit 310 of the surface circuit board 30, solder mask ink is applied to the entire surface and pre-baked, and the solder mask ink forms a semi-cured ink layer 410; the entire board forms an ink layer processing board 40.

[0048] By applying solder mask ink to the front side and pre-baking the entire surface, the ink is made to be in a semi-cured state, which is beneficial to the subsequent processing of making the copper foil layer and removing the semi-cured ink layer 410.

[0049] Preferably, the solder mask ink is matte ink. Since a copper foil layer needs to be attached to the surface of the semi-cured ink layer 410 subsequently and the copper foil layer is finally etched off, the matte ink surface has basically no gloss and is not easily affected by the processing.

[0050] In this embodiment, forming the ink layer processing board 40 includes: Configure to form solder mask ink, take glue, add the glue to the solder mask ink, stir to form a composite ink system, apply the composite ink system to one side of the surface circuit 310 of the surface circuit board 30, and perform pre-baking, and the solder mask ink forms a semi-cured ink layer; the entire board forms an ink layer processing board 40.

[0051] Since the solder mask ink is generally an ink that is photo-cured and then thermally cured, its viscosity at room temperature is relatively low and its adhesion ability is relatively weak. Therefore, adding glue with a certain viscosity at room temperature can improve the viscosity and adhesion ability of the solder mask ink. After the subsequent process of laminating the copper foil layer, the copper foil layer adheres firmly to the surface of the semi-cured ink layer 410, preventing problems of peeling off or delamination.

[0052] It should be noted that the solder mask ink is generally printed on the surface of the surface circuit board 30 by screen printing. The composite ink system formed in this embodiment can be screen printed using a 34T screen or a 61T screen with a smaller mesh number, which can effectively prevent the screen holes from being blocked, and since the semi-cured ink layer 410 is made for the entire surface, there is no need to use a dot screen for processing.

[0053] It is also possible to select an aluminum sheet screen or a copper sheet screen, make a pattern corresponding to the area where the semi-cured ink layer 410 needs to be made, and perform processing.

[0054] Furthermore, the glue is epoxy resin glue or phenolic resin glue.

[0055] Since the main components of the solder mask ink are organic polymer components such as epoxy resin or phenolic resin, adding epoxy resin glue or phenolic resin glue forms a similar solubility effect with the main body of the solder mask ink, and the components are more uniform.

[0056] Furthermore, the viscosity of the glue at a temperature of 25°C ± 5°C is 900 mPa·s to 5000 mPa·s, preferably 1500 mPa·s, 2000 mPa·s, or 3000 mPa·s.

[0057] The adhesion of the glue viscosity to the copper foil layer is sufficient. Excessive adhesion may cause problems such as clogging of the mesh holes.

[0058] Furthermore, the pre-baking is carried out at a temperature of 75°C ± 5°C for 25 minutes to 50 minutes.

[0059] The pre-baking is similar to that in the traditional processing flow and can transform the solder mask ink from a liquid state to a semi-dry state. During the subsequent processing, the ink will not flow and has viscosity.

[0060] Please refer to Figure 8 , Figure 8 which is a schematic cross-sectional structure diagram of the auxiliary graphic board fabricated according to the embodiment of the present invention.

[0061] Step S60: Take the copper foil layer and press it on one side of the semi-cured ink layer 410. Stick the second dry film on the surface of the copper foil layer, and successively perform exposure and development on the second dry film according to the pad pattern 110 to form the second dry film pattern 510 and the second etching process. Etch away the copper foil layer corresponding to the pad pattern 110 to form the copper foil pattern layer 520, and the entire board forms the auxiliary graphic board 50.

[0062] Here, the copper foil layer is used as the auxiliary layer for graphic transfer processing. The copper foil layer forms graphic transfer through the second dry film pattern 510. The exposure accuracy of the second dry film pattern 510 is relatively high, and the development accuracy of the dry film is higher than the corresponding accuracy of the solder mask ink. Therefore, the formed graphic accuracy is higher, and the etched graphic accuracy formed after etching the copper foil layer is high. On the basis of the pre-large of the pad pattern 110, a structural feature of high-precision matching between the copper foil pattern layer 520 formed after etching and the pad pattern 110 is formed, providing high-precision graphic conditions for subsequent removal of part of the semi-cured ink layer 410.

[0063] It should be noted that the second dry film pattern 510 cannot be directly made on the surface of the semi-cured ink layer 410 in this process because their components are relatively similar. Directly making it will, on the one hand, damage the semi-cured ink layer 410 (due to the dry film development effect), and on the other hand, it is difficult to form a clear distinguishing interface between the dry film layer and the semi-cured ink layer 410, resulting in problems such as incomplete development or overdevelopment of the second dry film pattern 510.

[0064] Optionally, after forming the copper foil pattern layer 520, perform film stripping to remove the second dry film pattern 510.

[0065] In this process, the second dry film pattern 510 can be removed separately using the stripping line, or it can be removed together during the subsequent processing of removing the semi-cured ink layer 410.

[0066] In this embodiment, the copper foil layer is a thin copper foil layer, and the thickness of the thin copper foil layer is 5 μm to 20 μm.

[0067] Since the copper foil layer is only used as an auxiliary layer and does not need to be retained on the circuit board surface finally, according to the actual application requirements, a copper foil layer with a relatively thin thickness is preferably selected to reduce the processing difficulty and the impact of the etching amount on the circuit board body.

[0068] Please refer to Figure 9 、 Figure 10 and Figure 11 , Figure 9 which is a schematic cross-sectional structure diagram of the solder mask removing board formed in the embodiment of the present invention; Figure 10 which is a schematic cross-sectional structure diagram of the high-precision pad circuit board formed in the embodiment of the present invention; Figure 11 is Figure 10 the schematic plan view.

[0069] Step S70: Process the auxiliary pattern board 50 to remove the semi-cured ink layer 410 to form a solder mask removing board 60 (please refer to Figure 9 ), and the semi-cured ink layer 410 covering the surface of the pad pattern 110 is removed; then bake and cure the solder mask removing board 60, and the semi-cured ink layer 410 that is not removed forms a solder mask pattern 610, and then perform the third etching to etch away the remaining copper foil layer to form a high-precision pad circuit board 70.

[0070] In this process, the semi-cured ink layer 410 is directly removed. Since the above process forms the graphic basis of the copper foil graphic layer 520, and this graphic is made corresponding to the pad pattern 110, so this process directly removes the semi-cured ink layer 410 covering the surface of the pad pattern 110 to expose the pad pattern 110, and the pad pattern 110 has already formed a surface treatment layer 210 in the previous process and has formed a complete pad, so there is no need to perform surface treatment again.

[0071] After baking and curing, the solder mask pattern 610 changes from a semi-cured state to a fully cured state, forming an effective and good solder mask layer.

[0072] Optionally, after etching away the remaining copper foil layer, the board body is polished, and in the way of micro-polishing or polishing, the impurities on the surface of the formed solder mask pattern 610 are polished away to make the surface flat.

[0073] In this embodiment, removing the semi-cured ink layer 410 is to pass the auxiliary pattern board 50 through a film stripping processing line or a solder mask stripping processing line for stripping processing.

[0074] Since the semi-cured ink layer 410 has only undergone pre-baking and is in an incompletely cured state (the solder mask layer has not been completely formed into macromolecules), a film stripping line for the solder mask process can be used for film stripping. The film stripping solution of the film stripping line is generally a low-concentration strong alkali solution, such as NaOH solution, KOH solution, or an organic strong alkali solution, which can effectively remove the semi-cured ink layer 410; further, to prevent the semi-cured ink layer 410 from being affected by time factors or other process factors during processing and causing certain curing, a solder mask stripping processing line with stronger stripping ability can be used for processing. Its processing principle is similar to that of the film stripping line, but the solution concentration is greater, the temperature is higher, and the alkalinity is stronger.

[0075] Please refer to Figure 12 and Figure 13 , Figure 12 which is a schematic plan view of another dry film pattern board formed in the embodiment of the present invention; Figure 13 which is a schematic plan view of another surface circuit board formed in the embodiment of the present invention.

[0076] In one embodiment, forming another dry film pattern board 10A includes: pasting a first dry film on one side of the copper layer 1010 of the copper clad laminate 100, and sequentially performing exposure and development processing on the first dry film according to the pre-large pad pattern 110Y to form a first dry film pattern 120. The parts developed away expose the pre-large pad pattern 110Y, and the whole board forms another dry film pattern board 10A.

[0077] The process of forming the surface treatment board 20 remains unchanged. Please refer to the above step S30.

[0078] Forming another surface circuit board 30A includes: pasting a photosensitive dry film on one side of the surface treatment layer 210 of the surface treatment board 20, sequentially performing exposure and development on the photosensitive dry film according to the circuit pattern to form a photosensitive dry film pattern 120A, then performing the first etching, and then stripping the film. The copper layer 1010 forms a surface circuit 310, and the whole board forms another surface circuit board 30A.

[0079] The post-processing flow remains unchanged. Please refer to the above steps S50 to S70.

[0080] In this embodiment, a manufacturing method is adopted in which only the pre-large pad pattern 110Y is exposed by the first dry film pattern 120 (the rest of the area is fully covered). During surface treatment, only the surface treatment layer 210 of the pre-large pad pattern 110Y is formed, and the surface treatment layer 210 is not formed on the other surface circuits 310. The effect is that when the circuits are relatively dense, if the entire board is subjected to surface treatment, a large amount of chemical solution is used and the processing cost is high. Therefore, by adopting this method, the effect of only making the surface treatment for the pre-large pad pattern 110Y is achieved.

[0081] Correspondingly, the manufacturing method of the other surface circuit board 30A needs to be matched with that of the other dry film pattern board 10A. Since the pre-large pad pattern 110Y of the formed other dry film pattern board 10A is made to form the surface treatment layer 210, and the surface circuits 310 have not been made in the other areas of the copper layer 1010, it is necessary to separately attach a photosensitive dry film and make a photosensitive dry film pattern 120A, and further make the surface circuits 310.

[0082] In summary, for the high-precision pad circuit board 70 manufactured in this embodiment, the effect that the solder mask pattern 610 partially covers the pre-large pad pattern 110Y is formed, making the functional area pattern of the pad pattern 110 more regular. The overall process adopts a reverse manufacturing method. The surface treatment layer 210 is used to form the coverage of the surface circuits 310 to complete the first etching process. The copper foil pattern layer 520 is used to form the coverage of the semi-cured ink layer 410 to complete the process of removing the semi-cured ink layer 410 covering the surface of the pad pattern 110, replacing the processing process of directly screen-printing, pre-baking, aligning, exposing, and developing the solder mask ink. The processing precision of the pad pattern 110 is effectively improved, and a high-precision pad pattern 110 with an error range within ±5 μm is processed. The overall manufacturing method is efficient and convenient, the accuracy requirement for the alignment parameters that need to be mutually referenced during the processing is reduced, the processability is stronger, and the front and back processes have good relevance.

[0083] It should be noted that since the design and processing process of the circuit board are relatively precise, the structure and dimensions such as the thickness between layers and the line width in the actual processing process are all at the micron level. If the drawings are made according to the enlarged scale of the actual structure, the problem of unclear illustration will occur. Therefore, in order to more clearly and intuitively represent the implementation process of the manufacturing method of this embodiment, the drawings of this embodiment are all schematic diagrams of the enlarged technical features, which do not represent the dimensions of the actual structure, nor are they enlarged diagrams of the actual structure in proportion.

[0084] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a high-precision pad circuit board by combining a material with a pattern, characterized in that, The method for manufacturing a high-precision pad circuit board includes the following steps: S10: Take a copper clad laminate, design a circuit pattern on it. The circuit pattern includes a pad pattern. Enlarge the pad pattern preliminarily to form a preliminarily enlarged pad pattern. S20: Attach a first dry film to one side of the copper layer of the copper clad laminate, and sequentially perform exposure and development processes on the first dry film according to the circuit pattern to form a first dry film pattern. The parts removed by development are exposed to form the circuit pattern, including exposing the preliminarily enlarged pad pattern, and the whole board forms a dry film pattern board. S30: Perform surface treatment on the dry film pattern board to form a surface treatment layer on the surface of the circuit pattern, and then strip the film. The whole board forms a surface treatment board. S40: Perform the first etching on the surface treatment board. The area corresponding to the surface treatment layer forms surface circuits, and the whole board forms a surface circuit board. S50: Make solder resist ink on the whole surface of one side of the surface circuits of the surface circuit board and perform pre-baking. The solder resist ink forms a semi-cured ink layer. The whole board forms an ink layer processing board. S60: Take a copper foil layer, press it on one side of the semi-cured ink layer, attach a second dry film to the surface of the copper foil layer, and sequentially perform exposure, development, and the second etching processes on the second dry film according to the pad pattern. Etch away the copper foil layer corresponding to the pad pattern. The whole board forms an auxiliary pattern board. S70: Perform the process of stripping the semi-cured ink layer on the auxiliary pattern board to form a solder resist stripped board. The semi-cured ink layer covering the surface of the pad pattern is stripped off. Then bake and cure the solder resist stripped board, and perform the third etching to etch away the remaining copper foil layer to form the high-precision pad circuit board.

2. The method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 1, characterized in that, Forming the dry film pattern board includes: Attach the first dry film to one side of the copper layer of the copper clad laminate, and sequentially perform exposure and development processes on the first dry film according to the preliminarily enlarged pad pattern to form the first dry film pattern. The parts removed by development are exposed to the preliminarily enlarged pad pattern, and the whole board forms the dry film pattern board. Forming the surface circuit board includes: Attach a photosensitive dry film to one side of the surface treatment layer of the surface treatment board, sequentially perform exposure and development on the photosensitive dry film according to the circuit pattern, then perform the first etching, and then strip the film. The copper layer forms the surface circuits, and the whole board forms the surface circuit board.

3. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, Forming the ink layer processing board includes: Configure the solder resist ink, take glue, add the glue into the solder resist ink and stir to form a composite ink system. Make the composite ink system on one side of the surface circuits of the surface circuit board and perform pre-baking. The solder resist ink forms a semi-cured ink layer. The whole board forms the ink layer processing board.

4. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 3, characterized in that, The glue is epoxy resin glue or phenolic resin glue.

5. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 3, characterized in that, The viscosity of the glue at a temperature of 25°C ± 5°C is 900 mPa·s to 5000 mPa·s.

6. A method for fabricating a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, Preliminarily enlarging the pad pattern means enlarging each side by 30 μm to 100 μm.

7. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, The surface treatment is surface treatment of electroplating gold or immersion nickel gold.

8. A method for fabricating a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, The pre-baking is carried out at a temperature of 75°C ± 5°C for 25 to 50 minutes.

9. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, The copper foil layer is a thin copper foil layer, and the thickness of the thin copper foil layer is 5 μm to 20 μm.

10. A method for manufacturing a high-precision pad circuit board by matching a material with a pattern according to claim 1 or 2, characterized in that, Removing the semi-cured ink layer is to pass the auxiliary graphic board through a film stripping processing line or a solder mask stripping processing line for stripping processing.

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