Manufacturing method of high-precision circuit board based on material transformation

Abstract

The invention discloses a method for manufacturing a high-precision circuit board based on material transfer, which comprises the following steps of: taking a thick copper layer, attaching a micro-mucous membrane layer, manufacturing a dry film pattern layer on the other surface, etching off a part of thickness of the thick copper layer, stripping a film, screen-printing solder resist ink, baking and curing, polishing, forming a solder resist ink pattern, laminating an insulating medium layer, and stripping the micro-mucous membrane layer. Etching for the second time to form a circuit pattern layer, and performing surface treatment to form the high-precision circuit board; a reverse processing flow is formed through a material transfer mode, a semi-circuit layer is firstly manufactured, then solder resist ink is directly screen-printed to form a solder resist pattern, then the pattern is transferred to an insulating medium layer, the manufactured circuit pattern and the solder resist pattern are etched and exposed, alignment and exposure are carried out only once, the circuit processing precision is greatly improved, and the production cost is reduced. The solder resist pattern is not subjected to exposure and development processing, the phenomena of irregular pattern edge and lateral erosion are avoided, the whole processing flow is efficient and convenient, and a high-precision circuit board product is formed.

Description

Technical Field

[0001] The present invention relates to the fields of printed circuit board design and printed circuit board processing, and particularly relates to a method for manufacturing a high-precision circuit board based on material conversion. Background Art

[0002] A circuit board is an essential load-bearing component of an electronic module and is widely used in various fields, performing the most basic circuit conduction and distribution functions.

[0003] With the development of technology, for some precision instrument fields, high-precision circuit boards are required. Currently, high-precision circuit boards generally adopt the method of circuit pattern transfer (i.e., pre-treatment → dry film lamination → alignment and exposure → development → etching → film stripping) to form circuit patterns, and then adopt the method of solder mask pattern transfer (i.e., pre-treatment → screen printing of solder mask ink → pre-baking → alignment and exposure → development → curing) to manufacture high-precision circuit boards.

[0004] However, this method is a traditional manufacturing method. Generally, only by controlling the parameters in the processing process, or controlling the alignment patterns and alignment methods that are interrelated, controlling the etching method and etching amount, and controlling the methods and parameters of solder mask exposure and development, to achieve a high-precision processing effect. But on the one hand, this type of method is only a control method in production processing and mathematical principles, not an actual technical method. On the other hand, for high-precision circuit boards that require sensitive test pads, this type of method is also difficult to meet the processing accuracy requirements.

[0005] Based on the above background, starting from the perspective of material conversion, a method for manufacturing a high-precision circuit board is provided. Summary of the Invention

[0006] The present invention aims to solve the problems of large processing errors and irregular pad patterns and solder mask patterns generated when manufacturing circuit patterns and solder mask patterns using the prior art, and provides a method for manufacturing a high-precision circuit board based on material conversion. The manufacturing method includes the following steps: S10: Take a thick copper layer, attach a micro-mucosa layer to one side of the thick copper layer, attach a dry film to the other side of the thick copper layer, and form a dry film pattern layer, and overall form a pattern transfer structure; S20: Perform a first etching on the pattern transfer structure, etch away a part of the thickness of the thick copper layer to form a semi-circuit layer and a semi-copper layer, and then perform film stripping to overall form a semi-circuit pattern structure; S30: Screen-print solder mask ink on one side of the semi-circuit layer to fill the gaps in the circuit patterns of the semi-circuit layer, then bake and cure, and polish. The solder mask ink forms a solder mask ink pattern after polishing, and overall forms a solder mask ink pattern structure; S40: Press an insulating dielectric layer onto one side of the solder resist ink pattern of the solder resist ink pattern structure, and then peel off the micro-mucosal layer to form a copper surface transfer structure; S50: Perform a second etching on the copper surface transfer structure to etch away the semi-copper layer, form a circuit pattern layer, and perform surface treatment to form the high-precision circuit board.

[0007] Optionally, the thickness of the thick copper layer is 50 μm to 350 μm.

[0008] Optionally, the thickness of the semi-copper layer is 5 μm to 50 μm.

[0009] Optionally, after attaching the micro-mucosal layer, attach a support layer to one side of the micro-mucosal layer; before peeling off the micro-mucosal layer, peel off the support layer.

[0010] Optionally, the support layer is an FR-4 board layer, a polytetrafluoroethylene layer, a polyimide layer, or an epoxy resin layer.

[0011] Optionally, the dry film attachment is to attach a high-resolution dry film with a line width / line pitch ≤ 15 μm / 15 μm; the formation of the dry film pattern layer is to expose the dry film using an LDI exposure machine and then develop it.

[0012] Optionally, for the baking and curing, bake at a temperature of 70 °C to 80 °C for 40 minutes to 50 minutes, and then bake at a temperature of 100 °C to 125 °C for 60 minutes to 180 minutes.

[0013] Optionally, the insulating dielectric layer is a prepreg or a polyimide cover film.

[0014] Optionally, for the pressing of the insulating dielectric layer, perform plasma activation processing on the solder resist ink pattern structure, then perform browning treatment, and then press the insulating dielectric layer.

[0015] Optionally, the heating rate of the pressing is 1.5 °C / minute to 2.5 °C / minute, and the pressing time ≥ 20 minutes under the condition of the highest temperature of the pressing material temperature.

[0016] The present invention uses a dry film material to first fabricate a semi - circuit layer, then directly screen - print a solder mask ink material onto the semi - circuit pattern to form a solder mask pattern, and then through reverse transfer of the pattern, transfer it onto an insulating dielectric layer material. After that, directly etch away the semi - copper layer to expose the fabricated circuit pattern and solder mask pattern. During the processing, different materials are used for conversion, forming a processing process that only aligns and exposes the circuit pattern once. The alignment and exposure accuracy of the circuit pattern is much greater than that of the existing technology in the processing of circuit patterns with one - time alignment and exposure and in the processing of solder mask patterns with two - time alignment and exposure. This significantly improves the circuit processing accuracy. Moreover, the solder mask ink directly forms and fabricates the solder mask pattern based on the conditions of the circuit pattern, and there is no microscopic gap between the circuit pattern and the solder mask pattern, further enhancing the processing accuracy of the circuit pattern and the solder mask pattern. That is, the present invention forms a "reverse" processing process (different from the prior art) of first fabricating the solder mask pattern and then laminating the insulating dielectric layer on the solder mask layer and the semi - circuit layer by converting materials. In fact, only one circuit pattern is fabricated, and other processing is completed based on this circuit pattern, and the traditional processing method of the solder mask pattern is cancelled. Therefore, the accuracy of the circuit pattern and the solder mask pattern can be significantly improved; the overall processing flow has the relevance of the front - and - back processes, and is efficient and convenient, and can fabricate a good high - precision circuit board product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0018] Figure 1 It is a process flow chart of the manufacturing method of the embodiment of the present invention; Figure 2 It is a cross - sectional view of the graphic transfer structure fabricated in the embodiment of the present invention; Figure 3 It is a cross - sectional view of the semi - circuit graphic structure fabricated in the embodiment of the present invention; Figure 4 It is a cross - sectional view of the solder mask ink screen - printing structure fabricated in the embodiment of the present invention; Figure 5 It is a cross - sectional view of the solder mask ink graphic structure fabricated in the embodiment of the present invention; Figure 6 It is a cross - sectional view of the copper - surface transfer structure fabricated in the embodiment of the present invention; Figure 7A cross-sectional view of the circuit pattern etching structure fabricated according to an embodiment of the present invention; Figure 8 A cross-sectional view of a high-precision circuit board fabricated according to an embodiment of the present invention.

[0019] Explanation of the reference numerals in the drawings: 100, pattern transfer structure; 110, thick copper layer; 120, micro-adhesive layer; 130, support layer; 140, dry film pattern layer; 200, semi-circuit pattern structure; 1110, semi-circuit layer; 1120, semi-copper layer; 300, solder mask screen printing structure; 310, solder mask ink; 400, solder mask pattern structure; 410, solder mask pattern; 500, copper surface transfer structure; 510, insulating dielectric layer; 600, circuit pattern etching structure; 1130, circuit pattern layer; 700, high-precision circuit board; 710, surface treatment layer.

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

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the 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 protection scope 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 drawings). If the specific posture changes, the directional indications will also change accordingly.

[0023] In addition, the descriptions such as "first" and "second" in the present invention 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, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. 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 ; Figure 1 A process flow chart of the manufacturing method according to an embodiment of the present invention.

[0025] The manufacturing method of the high-precision circuit board according to the embodiment of the present invention includes Figure 1It is formed by manufacturing a processing process flow including the following, and for specific descriptions, please refer to the following text.

[0026] Please refer to Figure 2 ; Figure 2 This is a cross-sectional schematic diagram of the pattern transfer structure formed for the embodiment of the present invention.

[0027] Step S10: Take the thick copper layer 110, attach a micro adhesive film layer 120 to one side of the thick copper layer 110, attach a dry film to the other side of the thick copper layer 110, and manufacture a dry film pattern layer 140, and overall manufacture a pattern transfer structure 100.

[0028] In this embodiment, through the "reverse" pattern processing and transfer method, the thick copper layer 110 can serve as the copper thickness basis for forming the semi-circuit layer 1110 and the semi-copper layer 1120 during subsequent processing. Attaching the micro adhesive film layer 120 can provide good support for the thick copper layer 110, form a "pseudo" copper clad laminate structure, and prevent problems such as bending, creasing, pulling, and tearing of the thick copper layer 110 during the processing.

[0029] In this embodiment, the thickness of the thick copper layer 110 is 50 μm to 350 μm, preferably 50 μm, 75 μm, and 100 μm.

[0030] The circuit board is processed according to the design data on the computer side. The thick copper layer 110 in this embodiment is equivalent to thickening the copper layer in the prior art. Due to the "reverse" processing process, the semi-circuit layer 1110 and the semi-copper layer 1120 are formed subsequently. Substantially, the thickness of the semi-circuit layer 1110 is the thickness of the circuit pattern layer 1130 that ultimately needs to be manufactured. Therefore, a part of the copper thickness needs to be reserved to manufacture the semi-copper layer 1120 during the processing. Therefore, a copper layer with a thicker copper thickness than that of the prior art method needs to be used and needs to be matched to the actual application process.

[0031] In this embodiment, the micro adhesive film layer 120 can optionally be an acrylic series micro adhesive film or an epoxy resin series micro adhesive film. It has no adhesiveness at room temperature and is pressed onto the board surface by high temperature and high pressure during application. It can resist acids and alkalis and high temperatures (generally resistant to high temperatures of ≤200 °C), and can ultimately be effectively peeled off; the micro adhesive film layer 120 can play a good supporting role during the processing and can be smoothly peeled off after the processing is completed.

[0032] In this embodiment, after attaching the micro adhesive film layer 120, a support layer 130 is attached to one side of the micro adhesive film layer 120; before subsequently peeling off the micro adhesive film layer 120, the support layer 130 is peeled off first.

[0033] In this embodiment, the support layer 130 is a FR-4 board layer, a polytetrafluoroethylene layer, a polyimide layer or an epoxy resin layer.

[0034] Preferably, according to actual processing requirements, the thickness of the support layer 130 is 50 μm to 1.0 mm.

[0035] When the selected thick copper layer 110 is relatively thin (for example: 50μm to 105μm), if only the micro-mucosal layer 120 is attached, and the micro-mucosal layer 120 is also relatively thin (generally ≤100μm in thickness), it is still prone to problems such as bending and creases. The support layer 130 can be used to further strengthen its structure. Generally, a commonly used plate material that can adhere to the micro-mucosal layer 120 and match the main material of the circuit board is selected, and the support layer 130 can further protect the micro-mucosal layer 120 to prevent problems such as debonding during processing.

[0036] In this embodiment, the dry film is a high-resolution dry film with a line width / line spacing ≤ 15 μm / 15 μm. The dry film graphic layer 140 is formed by exposing the dry film using an LDI exposure machine and then developing the dry film to form the dry film graphic layer 140.

[0037] The use of high-resolution dry film can ensure high-precision processing of circuit graphics during the graphic transfer process. Combined with the laser direct imaging exposure of the LDI exposure machine, it can effectively improve the exposure accuracy and avoid problems such as light scattering and secondary exposure errors caused by film exposure.

[0038] See also Figure 3 ; Figure 3 It is a cross-sectional schematic diagram of a half-circuit pattern structure formed in an embodiment of the present invention.

[0039] Step S20: The pattern transfer structure 100 is etched for the first time to partially etch away the thick copper layer 110 to form a half-circuit layer 1110 and a half-copper layer 1120 , and then the film is stripped to form a half-circuit pattern structure 200 as a whole.

[0040] The thickness of the semi-circuit layer 1110 is the thickness of the final circuit graphic layer 1130. The semi-copper layer 1120 provides overall support for the semi-circuit layer 1110 during the processing to prevent the semi-circuit layer 1110 from being scattered, skewed, etc. during the subsequent silk-screen solder mask ink 310 and other processing.

[0041] In this embodiment, the thickness of the half copper layer 1120 is 5 μm to 50 μm, preferably 10 μm, 15 μm, or 20 μm.

[0042] Since the semi-copper layer 1120 only serves to integrally connect the semi-circuit layer 1110 and needs to be completely etched away during the subsequent second etching, the thickness of the semi-copper layer 1120 should not be too thick, otherwise problems such as difficult etching, uneven etching, and material waste may occur during the second etching.

[0043] Please refer to Figure 4 and Figure 5 ; Figure 4 which is a cross-sectional schematic diagram of the solder mask screen printing structure formed in the embodiment of the present invention; Figure 5 which is a cross-sectional schematic diagram of the solder mask pattern structure formed in the embodiment of the present invention.

[0044] Step S30: Please refer to Figure 4 , screen-print the solder mask ink 310 on one side of the semi-circuit layer 1110 to fill the gaps in the circuit pattern of the semi-circuit layer 1110, forming the solder mask screen printing structure 300; please refer to Figure 5 , bake and cure the solder mask screen printing structure 300 and polish it. The solder mask ink 310 forms the solder mask pattern 410 after polishing, and the solder mask pattern structure 400 is integrally formed.

[0045] Since the semi-circuit layer 1110 is formed by the first etching, in the etched area, a groove pattern (i.e., the gap of the subsequent circuit pattern layer 1130) is formed. At this time, directly screen-print the solder mask ink 310 on the surface, that is, fill the groove with the solder mask ink 310, and after baking, curing, and polishing to be flat, the solder mask pattern 410 is formed. In the whole process, there is no need to consider the screen printing thickness, screen printing accuracy, and screen printing coverage area of the solder mask ink 310, as long as it is ensured that the solder mask ink 310 completely fills the groove without voids and bubbles, and there is no need for alignment and exposure processing, which greatly improves the processing accuracy of the solder mask pattern 410.

[0046] It should be noted that when screen-printing the solder mask ink 310, a dot screen can be used to improve the screen printing accuracy of the solder mask ink 310. After screen-printing the solder mask ink 310, the solder mask screen printing structure 300 can be placed in a vacuum chamber for vacuum pumping, or placed on a micro-vibration device for micro-vibration processing, so as to effectively discharge the bubbles that may be hidden in the solder mask ink 310 and ensure that the solder mask ink 310 completely fills the groove without voids and bubbles.

[0047] In this embodiment, the baking and curing is to bake at a temperature of 70°C to 80°C for 40 minutes to 50 minutes, and then bake at a temperature of 100°C to 125°C for 60 minutes to 180 minutes.

[0048] If a relatively high temperature is directly used for baking, it may cause the ink on the outer layer to cure too quickly, affecting the curing effect of the inner ink. Therefore, a method of low-temperature pre-baking plus high-temperature further baking is adopted to enable the ink to achieve a uniform and slow curing process.

[0049] Please refer to Figure 6 ; Figure 6 It is a cross-sectional schematic diagram of the copper surface transfer structure formed in the embodiment of the present invention.

[0050] Step S40: Press-fit an insulating dielectric layer 510 onto one side of the solder resist ink pattern 410 of the solder resist ink pattern structure 400, and then peel off the micro-mucosa layer 120 to form a copper surface transfer structure 500.

[0051] Optionally, if the support layer 130 is provided, the support layer 130 is peeled off before peeling off the micro-mucosa layer 120.

[0052] The press-fit insulating dielectric layer 510 is the dielectric layer required for the circuit board itself. In this embodiment, through the "reverse" processing process of first fabricating the circuit and the ink and then press-fitting the insulating dielectric layer 510, this step realizes the process of transferring the copper surface from one side to the other side, and the overall processing achieves the effect of one-time high-precision processing of the circuit pattern layer 1130 and the solder resist ink pattern 410.

[0053] In this embodiment, the insulating dielectric layer 510 is a prepreg or a polyimide cover film.

[0054] The material of the insulating dielectric layer 510 can be selected according to the actual situation. Generally, an epoxy resin composite glass fiber material is used. If a flexible circuit board needs to be formed finally, a polyimide cover film material can be used.

[0055] Further optionally, the prepreg is a high-flow prepreg, and the resin content is 65% to 75%.

[0056] During the press-fitting process at high temperature and high pressure, the high-resin-content prepreg has stronger adhesion and better fluidity, and can form a good bonding effect with the solder resist ink pattern structure 400, preventing problems such as cracks, delamination, and even board explosion during subsequent application due to poor bonding force.

[0057] Further optionally, the prepreg is formed by stacking a high-flow prepreg and a low-flow prepreg, where the high-flow prepreg faces the side of the solder resist ink pattern 410; the resin content of the low-flow prepreg is 50% to 60%; preferably, the thickness of the high-flow prepreg is 10 μm to 50 μm.

[0058] If the board needs to have strong rigidity and relatively stable expansion and contraction performance, then low-flow prepreg needs to be used as the insulating dielectric layer 510. However, the resin content of the low-flow prepreg is relatively low, and the bonding force between it and the solder mask ink pattern structure 400 after lamination is weak. Therefore, a high-flow prepreg is arranged between the solder mask ink pattern structure 400 and the low-flow prepreg to improve the interlayer bonding force.

[0059] In this embodiment, for the lamination of the insulating dielectric layer 510, after the plasma activation process is performed on the solder mask ink pattern structure 400, brownification treatment is carried out, and then the insulating dielectric layer 510 is laminated; the heating rate during lamination is 1.5 °C / min to 2.5 °C / min, and the lamination time ≥ 20 minutes under the condition of the highest temperature of the lamination material temperature.

[0060] When laminating the insulating dielectric layer 510, since there are the semi-circuit layer 1110 and the solder mask ink pattern 410 on the surface, which are made of copper material and solder mask ink 310 material respectively, first, plasma activation treatment is adopted to make the solder mask ink pattern 410 form a uniformly rough activated surface, and then brownification treatment is used to make the semi-circuit layer 1110 form a uniformly rough surface, providing high-reliability lamination processing conditions for lamination.

[0061] In this embodiment, the heating rate during lamination is 1.5 °C / min to 2.5 °C / min, and the lamination time ≥ 20 minutes under the condition of the highest temperature of the lamination material temperature, preferably 23 minutes, 25 minutes, 30 minutes.

[0062] The process of laminating the insulating dielectric layer 510 generally mainly depends on three parameters: temperature, time, and pressure. The lamination curve is generally a process of "heating and pressurizing → maintaining the highest temperature and the highest pressure → cooling and depressurizing". In this embodiment, due to the adoption of a "reverse" processing process, the insulating dielectric layer 510 is laminated to the surface of the solder mask ink pattern structure 400. To ensure the lamination effect and guarantee the interlayer bonding force, therefore, in the stage of "heating and pressurizing", a slow heating method is adopted, which can fully form the degree of transformation of the insulating dielectric layer 510 from the glassy state to the rubbery state, that is, enable the insulating dielectric layer 510 to form better fluidity and adhesiveness, improving the interlayer bonding force after lamination. After reaching the highest temperature, the lamination time ≥ 20 minutes under the condition of the highest temperature of the lamination material temperature, that is, a relatively long lamination time at the highest temperature is selected, which can further improve the adhesion between the insulating dielectric layer 510 and the solder mask ink pattern structure 400, improving the interlayer bonding force.

[0063] Since the insulating dielectric layer 510 selects different materials according to actual application requirements, the highest lamination temperature is a non-fixed and non-limiting parameter, which is specifically set according to the material situation.

[0064] Please refer to Figure 7 andFigure 8 ; Figure 7 It is a cross-sectional schematic diagram of a circuit pattern etching structure fabricated according to an embodiment of the present invention; Figure 8 It is a cross-sectional schematic diagram of a high-precision circuit board fabricated according to an embodiment of the present invention.

[0065] Step S50: Perform a second etching on the copper surface transfer structure 500 to etch away the semi-copper layer 1120, form a circuit pattern layer 1130, integrally form a circuit pattern etching structure 600, and perform surface treatment to form a surface treatment layer 710, thereby forming a high-precision circuit board 700.

[0066] It can be seen that the second etching directly etches the semi-copper layer 1120, and the semi-copper layer 1120 is an extra copper layer added. Therefore, there is no need to use the method of pattern transfer during etching (i.e., there is no need to use the method of pasting dry film → exposure → etching → development → film stripping for processing). Thus, it will not affect the circuit pattern layer 1130 due to alignment and exposure. The surface treatment layer 710 can effectively improve the electrical conductivity, oxidation resistance, wear resistance, and high-precision performance of the circuit pattern layer 1130.

[0067] In this embodiment, before surface treatment, bake the circuit pattern etching structure 600 at a temperature of 120°C to 135°C for 30 minutes to 60 minutes. The purpose is to thoroughly remove the internal stress in the board body and make the size of the board body more stable during application.

[0068] In summary, in this embodiment, by taking a thick copper layer 110 thicker than the circuit pattern in the design data, first fabricating half of the semi-circuit layer 1110, then directly fabricating a solder mask ink pattern 410 and transferring it onto the insulating dielectric layer 510, a high-precision circuit board 700 is formed through reverse processing. During this process, the micro-adhesive layer 120 is used to form support for the semi-circuit layer 1110 and the solder mask ink pattern 410. The entire processing process only performs dry film alignment and exposure once, greatly improving the circuit processing accuracy. The solder mask ink pattern 410 does not require alignment and exposure, and will not produce edge irregularities and side etching phenomena of the pattern itself. Moreover, the solder mask ink pattern 410 is formed by filling the circuit gaps and there is no fine gap between it and the circuit pattern. The overall processing accuracy is high, the processing flow is efficient and convenient, and it can fabricate a high-precision circuit board with the accuracy requirements of the solder pads and the solder mask ink pattern 410 reaching ±5μm.

[0069] It should be noted that the high-precision circuit board 700 of this embodiment can be further used to fabricate the structure of a multi-layer circuit board. That is, prepare at least two circuit pattern etching structures 600, and take several adhesive layer prepregs and arrange them alternately with the circuit pattern etching structures 600 in the layout mode of a multi-layer circuit board. Then, perform lamination, and then carry out processing such as drilling, electroplating, and outer layer pattern to form a multi-layer circuit board.

[0070] It should be noted that since the design and processing process of the circuit board are relatively precise, the structure in the actual processing process and the dimensions such as the thickness between layers and the line width 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 enlarged technical features, which do not represent the dimensions of the actual structure, nor are they enlarged diagrams of the actual structure in equal proportion.

[0071] 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 by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A manufacturing method of a high-precision circuit board based on material conversion, characterized in that, The manufacturing method includes the following steps: S10: Take a thick copper layer, attach a micro adhesive film layer to one side of the thick copper layer, attach a dry film to the other side of the thick copper layer, and fabricate a dry film pattern layer to form a pattern transfer structure integrally. S20: Conduct a first etching on the pattern transfer structure to etch away part of the thickness of the thick copper layer, forming a semi - circuit layer and a semi - copper layer, and then strip the film to form a semi - circuit pattern structure integrally. S30: Screen - print solder resist ink on one side of the semi - circuit layer to fill the gaps in the circuit pattern of the semi - circuit layer, then bake and cure it, and polish it. The solder resist ink forms a solder resist ink pattern after polishing to form a solder resist ink pattern structure integrally. S40: Press an insulating dielectric layer onto one side of the solder resist ink pattern of the solder resist ink pattern structure, and then peel off the micro adhesive film layer to form a copper - surface transfer structure. S50: Conduct a second etching on the copper - surface transfer structure to etch away the semi - copper layer, form a circuit pattern layer, and conduct surface treatment to form the high - precision circuit board.

2. The manufacturing method of a high-precision circuit board based on material conversion according to claim 1, wherein, The thickness of the thick copper layer is from 50 μm to 350 μm.

3. The manufacturing method of a high-precision circuit board based on material conversion as described in claim 1 or 2, characterized in that The thickness of the semi - copper layer is from 5 μm to 50 μm.

4. The manufacturing method of a high-precision circuit board based on material conversion according to claim 1, characterized in that, After attaching the micro adhesive film layer, attach a support layer to one side of the micro adhesive film layer; before peeling off the micro adhesive film layer, peel off the support layer.

5. The manufacturing method of a high-precision circuit board based on material conversion as claimed in claim 4, wherein, The support layer is an FR - 4 board layer, a polytetrafluoroethylene layer, a polyimide layer, or an epoxy resin layer.

6. The manufacturing method of a high-precision circuit board based on material conversion as described in claim 1, wherein, The dry - film attachment is to attach a high - resolution dry film with a line width / line pitch ≤ 15 μm / 15 μm. The fabrication of the dry - film pattern layer is to expose the dry film using an LDI exposure machine and then develop it.

7. The manufacturing method of a high-precision circuit board based on material conversion according to claim 1, characterized in that, The baking and curing is to bake at a temperature of 70 °C to 80 °C for 40 minutes to 50 minutes, and then bake at a temperature of 100 °C to 125 °C for 60 minutes to 180 minutes.

8. The manufacturing method of a high-precision circuit board based on material conversion according to claim 1, characterized in that, The insulating dielectric layer is a prepreg or a polyimide cover film.

9. The manufacturing method of a high-precision circuit board based on material conversion as claimed in claim 1 or 8, wherein The pressing of the insulating dielectric layer is to conduct plasma activation processing on the solder resist ink pattern structure, then conduct browning treatment, and then press the insulating dielectric layer.

10. The manufacturing method of a high-precision circuit board based on material conversion as described in claim 9, wherein The heating rate of the pressing is 1.5 °C / minute to 2.5 °C / minute, and the pressing time ≥ 20 minutes under the condition of the highest temperature of the material temperature during the pressing.

Images