A method for manufacturing a high-precision pad circuit board by combining materials and patterns

Abstract

The present invention discloses a method for manufacturing a high-precision pad circuit board by combining materials and patterns. The method comprises the following steps: pre-enlarging the pad pattern, surface treating the pad pattern, etching for the first time to form a surface circuit, manufacturing solder resist ink on the entire surface, pre-baking to form a semi-cured ink layer, taking a copper foil layer, pressing it onto one side of the semi-cured ink layer, manufacturing a copper foil pattern layer according to the pad pattern, then performing a process of removing the semi-cured ink layer, removing the semi-cured ink layer covering the surface of the pad pattern, baking and curing, and etching for the third time to form a high-precision pad circuit board. The pad pattern is pre-enlarged to form a basis for manufacturing a solder resist window smaller than the pad pattern, the surface treatment layer is used to block the circuit pattern, the copper foil pattern layer is used to manufacture a surface solder resist pattern, and the high-precision pad pattern is manufactured. The overall manufacturing process is convenient and efficient, and the process correlation is high.

Description

Technical Field

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

[0002] At present, some high-precision medical testing and analysis instruments are gradually developing towards portable applications to meet the needs of efficient, convenient and fast response in medical testing, and can even achieve the effect of self-testing at home. The test cards supporting such high-precision medical testing and analysis instruments require high pad accuracy for the built-in basic circuit board to ensure data accuracy during the high-precision analysis process. The pads on the surface of the circuit board are generally achieved by etching the circuit pattern and making a solder mask pattern, and then performing surface treatment. That is, for the pads that need to be exposed, a solder mask window treatment is performed, and for the surfaces that do not need to be exposed, a solder mask layer is used to cover. Therefore, when making the solder mask pattern (exposing the surface pads), this type of high-precision pad circuit board is required to have the characteristics of high precision, accurate position and small dimensional error.

[0003] At present, the general approach is to improve the alignment and exposure accuracy, repeatedly test and verify the factors affecting the expansion and shrinkage of different exposure and development processes, as well as copper electroplating, gold electroplating and other processes, to determine the best processing flow and processing parameters and improve the graphic processing accuracy of the pad.

[0004] However, on the one hand, this method still fails to solve the problem of high-precision pad processing from the technical point of view itself. It only explores a large amount of data on the selectivity of existing processing procedures, processing equipment, and processing materials to improve processing accuracy. In addition, there are many factors that affect the pad processing accuracy. A large amount of testing and verification will increase the workload, and changes in actual processing conditions will make the data more sensitive, increase uncertainty, and make it difficult to form a stable processing method. On the other hand, after the solder mask ink is used to form the solder mask pattern, side etching will occur, and the degree of side etching at different positions is different. Therefore, the problem of uneven edges of the solder mask pattern will occur in the microscopic state, reducing the accuracy of the pad.

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

[0006] The present invention aims to solve the problem of low pad precision during the production process of a circuit board with high-precision pads, and provides a method for producing a high-precision pad circuit board by combining materials and patterns, comprising the following steps:

[0007] S10: taking a copper clad laminate, designing a circuit pattern therefor, the circuit pattern including a pad pattern, and pre-enlarging the pad pattern to form a pre-enlarged pad pattern;

[0008] S20: applying a first dry film to one side of the copper layer of the copper clad laminate, and sequentially exposing and developing the first dry film according to the circuit pattern to form a first dry film pattern, wherein the developed portion is exposed to form the circuit pattern, including exposing the pre-enlarged pad pattern, and the entire board is formed into a dry film pattern board;

[0009] S30: performing surface treatment on the dry film graphic board to form a surface treatment layer on the surface of the circuit pattern, and then removing the film to form a surface treated board;

[0010] S40: performing a first etching on the surface treatment plate, forming a surface circuit in the area corresponding to the surface treatment layer, and forming a surface circuit board on the entire plate;

[0011] S50: preparing solder resist ink on the entire surface of the surface circuit board and pre-baking the solder resist ink to form a semi-cured ink layer; and forming an ink layer on the entire board;

[0012] S60: taking a copper foil layer, pressing it onto one side of the semi-cured ink layer, applying a second dry film to the surface of the copper foil layer, and sequentially exposing, developing, and etching the second dry film according to the pad pattern, etching away the copper foil layer corresponding to the pad pattern, and forming an auxiliary pattern plate on the entire board;

[0013] S70: The auxiliary graphic board is processed to remove the semi-cured ink layer to form a faded solder resist board, and the semi-cured ink layer covering the surface of the pad pattern is faded; then the faded solder resist board is baked and cured, and then etched for a third time to etch away the remaining copper foil layer to form the high-precision pad circuit board.

[0014] Optionally, forming the dry film graphic board includes: attaching the first dry film to one side of the copper layer of the copper clad board, and sequentially exposing and developing the first dry film according to the pre-large pad pattern to form the first dry film pattern, with the developed portion exposing the pre-large pad pattern, and the entire board forms the dry film graphic 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, and sequentially exposing and developing the photosensitive dry film according to the circuit pattern, then performing the first etching, and then stripping the film, so that the copper layer forms the surface circuit, and the entire board forms the surface circuit board.

[0015] Optionally, forming the ink layer processing board includes: configuring the solder resist ink, taking glue, adding the glue into the solder resist ink, stirring to form a composite ink system, making the composite ink system onto one side of the surface circuit of the surface circuit board, and pre-baking, and the solder resist ink forms a semi-cured ink layer; and forming the ink layer processing board on the entire board.

[0016] Optionally, the glue is epoxy resin glue or phenolic resin glue.

[0017] Optionally, the viscosity of the glue at a temperature of 25°C±5°C is 900mPa.s to 5000mPa.s.

[0018] Optionally, the pad pattern is pre-enlarged by 30 μm to 100 μm on a single side.

[0019] Optionally, the surface treatment is gold electroplating or nickel-immersion gold surface treatment.

[0020] Optionally, the pre-baking is performed at a temperature of 75° C.±5° C. for 25 to 50 minutes.

[0021] 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.

[0022] Optionally, removing the semi-cured ink layer is to pass the auxiliary graphic plate through a film removal processing line or a solder resist removal processing line for removal processing.

[0023] In the technical solution of the present invention, the pad pattern is pre-enlarged to form a pre-enlarged pad pattern, thereby preparing a pad pattern foundation for making a solder mask window smaller than the pad pattern; by adopting a reverse process, solder mask ink is first made on the entire board to form a semi-cured ink layer, and then a copper foil layer is used to form a copper foil pattern layer. As an auxiliary tool, the semi-cured ink layer is removed with a chemical solution 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 pattern processing process, and using a higher-precision copper foil pattern layer as an auxiliary layer to limit the pattern area, thereby greatly improving the processing accuracy of the pad; the overall processing process forms a relatively convenient processing process through the cooperation of dry film materials, solder mask ink materials, copper foil layer materials and other materials with the pattern processing process, reducing the precision requirements for processing accuracy such as mutual reference alignment, improving operability, and each processing process has a strong correlation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0025] Figure 1This is a schematic diagram of the cross-sectional structure of a high-precision pad circuit board in the prior art;

[0026] Figure 2 This is a schematic diagram of the planar structure of a high-precision pad circuit board in the prior art;

[0027] Figure 3 This is a process flow chart for manufacturing a high-precision pad circuit board according to an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of the cross-sectional structure of a dry film graphic plate produced according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the cross-sectional structure of a surface treatment plate produced according to an embodiment of the present invention;

[0030] Figure 6 A schematic diagram of the cross-sectional structure of a surface circuit board fabricated in accordance with an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the cross-sectional structure of a processing plate for forming an ink layer according to an embodiment of the present invention;

[0032] Figure 8 A schematic diagram of a cross-sectional structure of an auxiliary graphic plate formed in accordance with an embodiment of the present invention;

[0033] Figure 9 A schematic diagram of the cross-sectional structure of a resist-removing soldering plate produced in accordance with an embodiment of the present invention;

[0034] Figure 10 A schematic diagram of the cross-sectional structure of a high-precision pad circuit board manufactured in accordance with an embodiment of the present invention;

[0035] Figure 11 for Figure 10 Schematic diagram of the plane structure;

[0036] Figure 12 A schematic diagram of the planar structure of another dry film graphic plate produced according to an embodiment of the present invention;

[0037] Figure 13 This is a schematic diagram of the planar structure of another surface circuit board manufactured according to an embodiment of the present invention.

[0038] Description of Figure Numbers:

[0039] 110X, prior art pad pattern; 210X, prior art surface treatment layer; 610X, prior art solder resist pattern; 6110X, prior art solder resist undercut; 1020X, prior art insulating dielectric layer; 10, dry film pattern board; 100, copper clad board; 110, pad pattern; 110Y, pre-enlarged 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, faded solder resist board; 610, solder resist pattern; 70, high-precision pad circuit board; 10A, another dry film pattern board; 120A, photosensitive dry film pattern; 30A, another surface circuit board.

[0040] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] 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 various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0044] See also Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the cross-sectional structure of a high-precision pad circuit board in the prior art; Figure 2 The figure is a schematic diagram of the planar structure of a high-precision pad circuit board in the prior art.

[0045] In the prior art, the surface of the prior art pad pattern 110X is made with a prior art surface treatment layer 210X, which is located between the prior art solder resist patterns 610X and are all made on the surface of the prior art insulating dielectric layer 1020X. That is, the prior art solder resist pattern 610X is formed by exposing and developing the solder resist ink layer. The prior art solder resist pattern 610X has the prior art solder resist undercut 6110X, which affects the processing accuracy of the prior art solder resist pattern 610X itself, making the edge of the prior art pad pattern 110X uneven in the plane direction (see Figure 2 ), affecting the accuracy of use.

[0046] See also Figure 3 , Figure 3 This is a flowchart of the high-precision pad circuit board processing process according to an embodiment of the present invention.

[0047] The production process of the embodiment of the present invention includes the following steps: Figure 3 The process shown is described below.

[0048] See also Figure 4 , Figure 4 Schematic diagram of the cross-sectional structure of a dry film graphic plate produced according to an embodiment of the present invention.

[0049] Step S10:

[0050] A copper clad laminate 100 is taken and a circuit pattern is designed thereon. The circuit pattern includes a pad pattern 110 . The pad pattern 110 is pre-enlarged to form a pre-enlarged pad pattern 110Y. The copper clad laminate 100 further includes an insulating dielectric layer 1020 .

[0051] Since a portion of the pad pattern 110 needs to be formed under the solder resist pattern 610 during post-processing in this embodiment, the pad pattern 110 is pre-enlarged to form a prerequisite for forming the pad pattern 110 under the solder resist pattern 610.

[0052] In this embodiment, the pad pattern 110 is pre-enlarged by 30 μm to 100 μm on one side.

[0053] According to the actual utilization area of ​​the board, just select the smallest pre-size.

[0054] Step S20:

[0055] A first dry film is applied to one side of the copper layer 1010 of the copper clad board 100, and the first dry film is sequentially exposed and developed according to the circuit pattern to form a first dry film pattern 120. The developed portion is exposed to form a circuit pattern, including exposing the pre-large pad pattern 110Y, and the entire board forms a dry film pattern board 10.

[0056] The dry film graphic board 10 thus produced provides a good surface foundation for subsequent surface treatment and the first etching.

[0057] Optionally, forming the first dry film pattern 120 is to perform exposure and development processing on the first dry film, which is a conventional method.

[0058] Optionally, the first dry film is an electroplating-resistant gold-plating dry film, and if the subsequent surface treatment is electroplating gold, the electroplating gold processing process is matched.

[0059] Optionally, the copper layer 1010 has a relatively thin thickness of 5 μm to 20 μm, which on the one hand meets the application requirements of the test card of the portable medical device, and on the other hand is conducive to subsequent etching processing, forming a fast etching and high-precision etching process.

[0060] See also Figure 5 , Figure 5 This is a schematic diagram of the cross-sectional structure of a surface treatment plate produced according to an embodiment of the present invention.

[0061] Step S30:

[0062] The dry film pattern board 10 is surface treated to form a surface treatment layer 210 on the surface of the circuit pattern. The film is then removed to form a surface treatment board 20 on the entire board.

[0063] This embodiment adopts the method of first forming a surface treatment layer 210, and then stripping and etching the other protected areas under the protection of the surface treatment layer 210 to form the required circuit pattern. The reverse process of first forming the surface treatment layer 210 and then forming the circuit pattern is adopted. On the one hand, compared with the prior art that adopts the process of dry film application, exposure, development, etching, and stripping to form the circuit pattern, and then forming the surface treatment layer 210 in the subsequent forward method, the processing process is shortened and the processing accuracy is improved. On the other hand, it can provide a differentiated condition basis for the subsequent direct production of the front solder mask ink on the board surface, which is convenient for the subsequent processing of exposing the pad pattern by stripping the semi-cured ink layer 410.

[0064] In this embodiment, the surface treatment is gold electroplating or nickel-immersion gold surface treatment.

[0065] Both electroplating gold and immersion nickel gold can form a gold layer, which can withstand the etching of subsequent processes and the impact of film stripping solutions. In this embodiment, it can not only play the role of dry film graphics, but also play the role of selectively protecting the copper surface. The gold layer of electroplated gold has a higher density, higher hardness, and a smoother surface, so electroplating gold processing is preferred.

[0066] See also Figure 6 , Figure 6 A schematic diagram of the cross-sectional structure of a surface circuit board fabricated in accordance with an embodiment of the present invention;

[0067] Step S40:

[0068] The surface treatment plate 20 is etched for the first time, and the area corresponding to the surface treatment layer 210 forms the surface circuit 310 , and the entire plate forms the surface circuit board 30 .

[0069] Continuing with the above process, after the film is stripped, the surface of the copper layer 1010 is divided into two areas, 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 solution, the copper layer 1010 in this area is protected, forming a circuit pattern, while the exposed copper surface is etched away.

[0070] Corresponding to the above surface treatment, electroplating gold or immersion nickel gold is preferred, and the gold layer can better withstand the impact of etching solution.

[0071] See also Figure 7 , Figure 7 This is a schematic diagram of the cross-sectional structure of a processing plate for forming an ink layer according to an embodiment of the present invention.

[0072] Step S50:

[0073] A solder resist ink is formed on the entire surface of the surface circuit board 30 on the surface circuit 310 and pre-baked to form a semi-cured ink layer 410 of the solder resist ink; and the entire board is formed with an ink layer processing board 40.

[0074] The solder resist ink is applied to the front surface and the entire surface is pre-baked to make the ink semi-cured, which is beneficial for the subsequent production of the copper foil layer and the removal of the semi-cured ink layer 410 .

[0075] Preferably, the solder resist ink is matte ink. Since a copper foil layer needs to be attached to the surface of the semi-cured ink layer 410 and finally etched away, the matte ink surface has basically no glossiness and is not easily affected by processing.

[0076] In this embodiment, forming the ink layer processing plate 40 includes:

[0077] A solder resist ink is prepared and glue is added to the solder resist ink, stirred to form a composite ink system, and the composite ink system is applied to one side of the surface circuit 310 of the surface circuit board 30 and pre-baked to form a semi-cured ink layer of the solder resist ink; the entire board forms an ink layer processing board 40.

[0078] Since solder resist ink is generally a light-cured and then heat-cured ink, its viscosity at room temperature is relatively low and its adhesion ability is relatively weak. Therefore, glue with a certain viscosity at room temperature is added to improve the viscosity and adhesion ability of the solder resist ink. After the copper foil layer is pressed in the subsequent process, the copper foil layer is firmly adhered to the surface of the semi-cured ink layer 410 to prevent falling off or delamination problems.

[0079] It is worth noting that solder resist ink is generally printed onto the surface of the surface circuit board 30 by silk screen printing. The composite ink system formed in this embodiment can be silk screened using a 34T screen or a 61T screen with a smaller mesh size, which can effectively prevent mesh clogging and produce a semi-cured ink layer 410 for the entire surface, so there is no need to use a dot screen for processing.

[0080] Alternatively, an aluminum sheet mesh or a copper sheet mesh may be used to form a pattern corresponding to the area where the semi-cured ink layer 410 is to be formed, and then processed.

[0081] Furthermore, the glue is epoxy resin glue or phenolic resin glue.

[0082] Since the main components of solder resist ink are organic polymer components such as epoxy resin or phenolic resin, the addition of epoxy resin glue or phenolic resin glue forms a similar miscible effect with the body of solder resist ink, making the components more uniform.

[0083] 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.

[0084] The viscosity of the glue can be such that it adheres to the copper foil layer. Excessive adhesion will cause problems such as clogging the mesh.

[0085] Furthermore, the pre-baking is performed at a temperature of 75° C.±5° C. for 25 to 50 minutes.

[0086] Pre-baking is similar to the pre-baking of traditional processing flow, which can transform the solder mask ink from liquid to semi-dry state. During the subsequent processing, the ink will not flow and will be sticky.

[0087] See also Figure 8 , Figure 8 This is a schematic diagram of the cross-sectional structure of an auxiliary graphic plate produced according to an embodiment of the present invention.

[0088] Step S60:

[0089] A copper foil layer is taken and pressed onto one side of the semi-cured ink layer 410. A second dry film is applied to the surface of the copper foil layer. The second dry film is exposed and developed in sequence according to the pad pattern 110 to form a second dry film pattern 510. A second etching process is performed to etch away the copper foil layer corresponding to the pad pattern 110 to form a copper foil pattern layer 520. The entire board is formed into an auxiliary pattern plate 50.

[0090] Here, the copper foil layer is used as an auxiliary layer for the pattern transfer process. The copper foil layer is transferred to the pattern 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 pattern accuracy is higher, and the etched pattern accuracy formed after the copper foil layer is etched is high. On the basis of pre-enlarging the pad pattern 110, the copper foil pattern layer 520 formed after etching has a structural feature of high-precision matching with the pad pattern 110, providing high-precision pattern conditions for the subsequent removal of part of the semi-cured ink layer 410.

[0091] It is worth noting that this process cannot directly form the second dry film pattern 510 on the surface of the semi-cured ink layer 410 because the two have similar compositions. Direct formation of the second dry film pattern 510 may damage the semi-cured ink layer 410 (due to dry film development). In addition, it may be difficult to form a clear interface between the dry film layer and the semi-cured ink layer 410, resulting in incomplete or overdevelopment of the second dry film pattern 510.

[0092] Optionally, after forming the copper foil pattern layer 520 , a film stripping process is performed to remove the second dry film pattern 510 .

[0093] In this process, the second dry film pattern 510 can be removed using a film-fading line alone, or it can be removed together with the subsequent process of removing the semi-cured ink layer 410 .

[0094] 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.

[0095] Since the copper foil layer is only used as an auxiliary layer and does not need to be retained on the circuit board surface in the end, according to the actual application requirements, try to choose a thinner copper foil layer to reduce the processing difficulty and reduce the impact of the etching amount on the circuit board body.

[0096] See also Figure 9 、 Figure 10 and Figure 11 , Figure 9 A schematic diagram of the cross-sectional structure of a resist-removing soldering plate produced in accordance with an embodiment of the present invention; Figure 10 A schematic diagram of the cross-sectional structure of a high-precision pad circuit board manufactured in accordance with an embodiment of the present invention; Figure 11 for Figure 10 Schematic diagram of the planar structure.

[0097] Step S70:

[0098] The auxiliary graphic plate 50 is processed to remove the semi-cured ink layer 410 to form a solder resist plate 60 (see Figure 9 ), the semi-cured ink layer 410 covering the surface of the pad pattern 110 is removed; then the solder resist board 60 is baked and cured, and the semi-cured ink layer 410 that has not been removed forms a solder resist pattern 610, and then a third etching is performed to etch away the remaining copper foil layer to form a high-precision pad circuit board 70.

[0099] This process uses a process of directly removing the semi-cured ink layer 410. Since the above process forms the pattern basis of the copper foil pattern layer 520, and the pattern corresponds to the pad pattern 110, this process directly removes the semi-cured ink layer 410 covering the surface of the pad pattern 110 to expose the pad pattern 110. The pad pattern 110 has already been formed into a surface treatment layer 210 in the previous process, and has formed a complete pad, so no surface treatment is required.

[0100] After baking and curing, the solder resist pattern 610 changes from a semi-cured state to a fully cured state, forming an effective and good solder resist layer.

[0101] Optionally, after etching away the remaining copper foil layer, the board is polished by micro-polishing or polishing to remove impurities on the surface of the formed solder resist pattern 610 to make the surface smooth.

[0102] In this embodiment, the semi-cured ink layer 410 is removed by passing the auxiliary graphic plate 50 through a film removal processing line or a solder resist removal processing line for removal.

[0103] Since the semi-cured ink layer 410 has only been pre-baked and is in an uncured state (the solder mask layer with large molecules has not been completely formed), it can be stripped using a stripping line for the solder mask process. The stripping solution of the 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 strip off the semi-cured ink layer 410; further, in order to prevent the semi-cured ink layer 410 from being affected by time factors or other process factors during the processing and producing a certain degree of solidification, a solder mask stripping processing line with stronger stripping ability can be used for processing. Its processing principle is similar to that of the stripping line, but the solution concentration is higher, the temperature is higher, and the alkalinity is stronger.

[0104] See also Figure 12 and Figure 13 , Figure 12 A schematic diagram of the planar structure of another dry film graphic plate produced according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the planar structure of another surface circuit board manufactured according to an embodiment of the present invention.

[0105] In one embodiment, forming another dry film pattern plate 10A includes: attaching a first dry film to one side of the copper layer 1010 of the copper clad laminate 100, and sequentially exposing and developing the first dry film according to the pre-enlarged pad pattern 110Y to form a first dry film pattern 120, with the developed portion exposing the pre-enlarged pad pattern 110Y, and forming another dry film pattern plate 10A on the entire board.

[0106] The process of forming the surface treatment plate 20 remains unchanged, please refer to the above step S30.

[0107] Forming another surface circuit board 30A includes: attaching a photosensitive dry film to one side of the surface treatment layer 210 of the surface treatment board 20, exposing and developing the photosensitive dry film in sequence according to the circuit pattern to form a photosensitive dry film pattern 120A, then performing a first etching, and then stripping the film, the copper layer 1010 forms the surface circuit 310, and the entire board forms another surface circuit board 30A.

[0108] The post-processing process remains unchanged, please refer to the above steps S50 to S70.

[0109] In this embodiment, a manufacturing method is adopted in which the first dry film pattern 120 only exposes the pre-enlarged pad pattern 110Y (the rest of the area is fully covered). During surface treatment, the surface treatment layer 210 is formed only on the pre-enlarged pad pattern 110Y, and the surface treatment layer 210 is not formed on other surface circuits 310. The effect is that when the circuits are relatively dense, if the surface treatment is performed on the entire board, the amount of chemicals used will be large and the processing cost will be high. Therefore, this method is adopted to achieve the effect of surface treatment only on the pre-enlarged pad pattern 110Y.

[0110] Correspondingly, the manufacturing method of the other surface circuit board 30A needs to match that of the other dry film graphic board 10A. Since the pre-large pad pattern 110Y of the other dry film graphic board 10A is used to form the surface treatment layer 210, and the other areas of the copper layer 1010 have not yet been used to form the surface circuit 310, it is necessary to separately attach a photosensitive dry film and manufacture a photosensitive dry film pattern 120A to further form the surface circuit 310.

[0111] In summary, the high-precision pad circuit board 70 produced in this embodiment forms an effect in which the solder resist pattern 610 partially covers the pre-enlarged pad pattern 110Y, making the active area pattern of the pad pattern 110 more regular. The overall process adopts a reverse production method, using the surface treatment layer 210 to form a cover for the surface circuit 310 to complete the first etching process, and using the copper foil pattern layer 520 to form a cover for 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. This replaces the direct silk screen printing, pre-baking, alignment, exposure, and development process of the solder resist ink, effectively improving the processing accuracy of the pad pattern 110, and processing a high-precision pad pattern 110 with an error range of ±5μm. The overall production method is efficient and convenient, and the accuracy requirements for the alignment parameters that need to be referenced to each other during the processing process are reduced, the processability is stronger, and the front and back processes have a good correlation.

[0112] It is worth noting that due to the relatively precise design and processing of circuit boards, the structure of the actual processing process and the thickness of each layer, line width and other dimensions are all at the micron level. If the drawings are made according to the enlarged ratio of the actual structure, the illustrations will be unclear. 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 that enlarge the technical features, which do not represent the size of the actual structure, nor are they enlarged drawings of the actual structure in proportion.

[0113] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's description and drawings, or direct / indirect applications in other related technical fields, within the scope of the present invention are included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a high-precision pad circuit board by combining materials and patterns, characterized in that: The method for manufacturing a high-precision pad circuit board comprises the following steps: S10: taking a copper clad laminate, designing a circuit pattern therefor, the circuit pattern including a pad pattern, and pre-enlarging the pad pattern to form a pre-enlarged pad pattern; S20: applying a first dry film to one side of the copper layer of the copper clad laminate, and sequentially exposing and developing the first dry film according to the circuit pattern to form a first dry film pattern, wherein the developed portion is exposed to form the circuit pattern, including exposing the pre-enlarged pad pattern, and the entire board is formed into a dry film pattern board; S30: performing surface treatment on the dry film graphic board to form a surface treatment layer on the surface of the circuit pattern, and then removing the film to form a surface treated board; S40: performing a first etching on the surface treatment plate, forming a surface circuit in the area corresponding to the surface treatment layer, and forming a surface circuit board on the entire plate; S50: preparing solder resist ink on the entire surface of the surface circuit board and pre-baking the solder resist ink to form a semi-cured ink layer; and forming an ink layer on the entire board; S60: taking a copper foil layer, pressing it onto one side of the semi-cured ink layer, applying a second dry film to the surface of the copper foil layer, and sequentially exposing, developing, and etching the second dry film according to the pad pattern, etching away the copper foil layer corresponding to the pad pattern, and forming an auxiliary pattern plate on the entire board; S70: The auxiliary graphic board is processed to remove the semi-cured ink layer to form a faded solder resist board, and the semi-cured ink layer covering the surface of the pad pattern is faded; then the faded solder resist board is baked and cured, and then etched for a third time 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 combining materials and patterns according to claim 1, characterized in that: Forming the dry film graphic plate includes: The first dry film is applied to the copper layer of the copper clad laminate, and the first dry film is sequentially exposed and developed according to the pre-enlarged pad pattern to form the first dry film pattern, with the pre-enlarged pad pattern exposed in the developed portion, and the dry film pattern plate is formed on the entire board; Forming the surface circuit board includes: A photosensitive dry film is attached to one side of the surface treatment layer of the surface treatment board, and the photosensitive dry film is sequentially exposed and developed according to the circuit pattern, and then the first etching is performed and the film is stripped. The copper layer forms the surface circuit, and the entire board forms the surface circuit board.

3. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 1 or 2, characterized in that: Forming the ink layer processing board includes: configuring the solder resist ink, taking glue, adding the glue into the solder resist ink, stirring to form a composite ink system, making the composite ink system on one side of the surface circuit of the surface circuit board, and pre-baking, the solder resist ink forms a semi-cured ink layer; and forming the ink layer processing board on the entire board.

4. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 3, characterized in that: The glue is epoxy resin glue or phenolic resin glue.

5. The method for manufacturing a high-precision pad circuit board by combining materials and patterns 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. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 1 or 2, characterized in that: The pad pattern is pre-enlarged to 30 μm to 100 μm on one side.

7. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 1 or 2, characterized in that: The surface treatment is gold electroplating or nickel-immersion gold surface treatment.

8. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 1 or 2, characterized in that: The pre-baking is performed at a temperature of 75° C.±5° C. for 25 to 50 minutes.

9. The method for manufacturing a high-precision pad circuit board by combining materials and patterns 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. The method for manufacturing a high-precision pad circuit board by combining materials and patterns according to claim 1 or 2, characterized in that: The semi-cured ink layer is removed by passing the auxiliary graphic plate through a film removal processing line or a solder resist removal processing line for removal processing.

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