High-copper-thickness micro-pitch insulated circuit manufacturing method, circuit board and manufacturing method thereof

Abstract

The invention discloses a high-copper-thickness fine-pitch insulated circuit manufacturing method, a circuit board and a manufacturing method thereof, and the circuit manufacturing method comprises the steps: drilling a via hole in a substrate, and then covering the two opposite surfaces of the substrate with dry films with the film thickness not less than 200 [mu] m respectively; performing exposure and development on the dry film according to the operation data to prepare a dry film pattern with the film width of 15-25 microns and the film spacing of not less than 15 microns; filling gaps of the dry film pattern with copper paste in a spraying manner, and baking and curing to obtain a circuit pattern prototype; and performing copper reduction on the circuit pattern prototype to a set copper thickness, thereby obtaining the circuit pattern which is high in copper thickness and insulated at a fine pitch. The circuit manufacturing method is simple and reasonable, and the obtained circuit pattern has the characteristics of high copper thickness, fine spacing and absolute insulation between line spacing, so that the circuit pattern has very good electrical performance, precision, reliability and heat dissipation performance in various aspects, and the use requirements of the chip market are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board, in particular to a high-copper-thickness micro-pitch insulation circuit manufacturing method, a circuit board and a manufacturing method thereof. BACKGROUND

[0002] With the advent of the era of big data, the demand for chip market is becoming more and more extensive, such as the heat problem caused by high-speed operation, small space packaging problem and so on are also more and more concerned. Among them, in order to solve the problem of small space packaging, it is necessary to make more efficient heat dissipation design on the substrate, such as: the circuit pattern can be designed in the form of high copper thickness and micro pitch; however, the current market commonly used several circuit pattern manufacturing processes are difficult to realize the above circuit pattern manufacturing, which is specifically shown in: 1) laser etching pattern process; in the process of laser etching processing, because the copper thickness is thick, the laser energy is easy to fluctuate, which will cause the middle insulation layer to be broken down, resulting in the failure of the whole product.

[0003] 2) etching bus and wire wrapping electroplating combined process; the combined process needs to be electroplated for many times when processing because the copper thickness is thick, and the electroplating method is easy to be limited by the dry film thickness, which causes the plated circuit pattern to be arc-shaped, the effective soldering area is small, and the product quality is not high.

[0004] Therefore, it is urgent to provide a manufacturing process which can realize the circuit pattern with high copper thickness and micro pitch characteristics. In view of this, the present application is proposed. SUMMARY

[0005] In order to overcome the above defects, the present application provides a high-copper-thickness micro-pitch insulation circuit manufacturing method, a circuit board and a manufacturing method thereof, which is novel, simple and reasonable. The obtained circuit pattern has the characteristics of high copper thickness, micro pitch and absolute insulation between line distances, so that the electrical performance, precision, reliability and heat dissipation performance of the circuit pattern are very good, which well meets the use requirements of chip market.

[0006] The technical scheme adopted by the present application to solve its technical problems is: a high-copper-thickness micro-pitch insulation circuit manufacturing method, comprising: Drilling a through hole on the substrate, and then respectively covering a dry film with a film thickness not less than 200μm on the opposite two surfaces of the substrate; Exposing and developing the dry film according to the operation data to obtain a dry film pattern with a film width of 15-25μm and a film pitch not less than 15μm; Filling copper paste in the gap of the dry film pattern in the form of spraying, and then obtaining a circuit pattern sketch after curing by baking; Reducing the obtained circuit pattern sketch to a set copper thickness to obtain a high-copper-thickness micro-pitch insulation circuit pattern.

[0007] As a further improvement of the present application, the dry film adopts a photosensitive adhesive film with insulation strength of 50-300kV / mm, rigidity modulus of 5-10Gpa, and temperature resistance value of 220-260℃.

[0008] As a further improvement of the present application, the spraying processing parameters are as follows: nozzle aperture of the spray gun is 0.5-1.5mm, spray gun distance is 15-30cm, spray gun moving speed is 0.1-0.5m / s, spraying pressure is 5-20MPa, spraying overlap rate is 50%-70%, and spraying times are 2-5.

[0009] As a further improvement of the present application, the baking adopts a sectional baking process, i.e., first baking at 50-70℃ for 30-50min to remove volatiles in the copper paste, and then baking at 200-250℃ for 50-70min to solidify the copper paste.

[0010] As a further improvement of the present application, the obtained circuit pattern surface opposite to the substrate and the dry film pattern surface opposite to the substrate are in the same horizontal plane through whole plate grinding.

[0011] As a further improvement of the present application, the substrate is made of high-temperature-resistant insulating material; and the copper thickness of the circuit pattern reaches 200μm±10μm.

[0012] The present application also provides a circuit board manufacturing method, comprising: The high-copper-thickness micro-spacing insulated circuit manufacturing method of the present application is used to manufacture the circuit pattern on the opposite surfaces of the substrate; A dry film A with film thickness not less than 200μm is arranged on the circuit pattern, and the dry film A is exposed and developed according to the operation data to obtain a dry film pattern A; the film width of the dry film pattern A is smaller than that of the dry film pattern; The copper paste is filled in the gap of the dry film pattern A in a spraying manner, and after baking and solidification, a copper column prototype electrically connected with the circuit pattern is obtained; The copper column prototype is reduced to a set copper thickness to obtain a copper column, and the circuit board is obtained.

[0013] As a further improvement of the present application, the surface of the obtained copper column opposite to the circuit pattern and the surface of the dry film pattern A opposite to the circuit pattern are in the same horizontal plane through whole plate grinding.

[0014] The present application also provides a circuit board manufactured by the circuit board manufacturing method of the present application.

[0015] The beneficial effects of the present application are: compared with the prior art, the high-copper-thickness micro-pitch insulated circuit manufacturing method provided by the present application has the following advantages: ① The present application successfully obtains a circuit pattern with high copper thickness, micro-pitch (micro-line distance) and absolute insulation between line distances by innovating the material and film thickness of the dry film, the manufacturing method of the circuit pattern sketch, etc. The electrical performance, precision, reliability, heat dissipation performance, etc. of the obtained circuit pattern are very good, and the use demand of the chip market is very well met. ② The high-copper-thickness micro-pitch insulated circuit manufacturing method provided by the present application not only completely avoids the problems existing in the prior art, but also the end surface flatness of the obtained circuit pattern is very high, the effective welding area is large, and the reliability of the product in subsequent use is significantly improved. ③ The circuit manufacturing method provided by the present application can be applied to any copper thickness and any line distance in actual operation, and the line distance can ensure absolute insulation, and the universality and practicality are very high. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The flow chart of the high-copper-thickness micro-pitch insulated circuit manufacturing method described in embodiment 1 of the present application; Figure 2 The cross-sectional structure schematic diagram of the substrate with a through hole in embodiment 1; Figure 3 The cross-sectional structure schematic diagram of the substrate after the dry film is respectively coated on the two opposite surfaces of the substrate in embodiment 1; Figure 4 The cross-sectional structure schematic diagram of the substrate after the dry film pattern is respectively prepared on the two opposite surfaces of the substrate in embodiment 1; Figure 5 The cross-sectional structure schematic diagram of the substrate after the circuit pattern sketch is respectively prepared on the two opposite surfaces of the substrate in embodiment 1; Figure 6 The cross-sectional structure schematic diagram of the substrate after the circuit pattern is respectively prepared on the two opposite surfaces of the substrate in embodiment 1; Figure 7 The flow chart of the circuit board manufacturing method described in embodiment 2 of the present application; Figure 8 The cross-sectional structure schematic diagram of the intermediate plate after the dry film A is respectively coated on the two opposite surfaces of the intermediate plate in embodiment 2 of the present application; Figure 9 The cross-sectional structure schematic diagram of the intermediate plate after the dry film pattern A is respectively prepared on the two opposite surfaces of the intermediate plate in embodiment 2 of the present application; Figure 10 The cross-sectional structure schematic diagram of the intermediate plate after the copper column sketch is respectively prepared on the two opposite surfaces of the intermediate plate in embodiment 2 of the present application; Figure 11 The cross-sectional structure schematic diagram of the circuit board obtained in embodiment 2 of the present application.

[0017] Referring to the accompanying drawings, the following explanations are provided: 1. Substrate; 10. Via; 2. Dry film; 20. Dry film pattern; 3. Circuit pattern prototype; 4. Circuit pattern; 5. Dry film A; 50. Dry film pattern A; 6. Copper pillar prototype; 7. Copper pillar. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Example 1:

[0020] Please see the appendix Figure 1 To be continued Figure 6 As shown, this embodiment 1 provides a method for fabricating a circuit with high copper thickness and fine-pitch insulation, including the following fabrication steps: S11. A substrate 1 made of a high-temperature resistant insulating material is provided. The high-temperature resistant insulating material may preferably be, but is not limited to, BT resin or ABF material. Moreover, in this embodiment, the thickness of the substrate 1 is not limited and is determined according to the product design requirements.

[0021] First, through holes 10 are drilled on the substrate 1 by mechanical drilling (see attached diagram). Figure 2 As shown), the via 10 is used for electrical interconnection of circuit patterns in subsequent processes; then, dry film 2 is applied to both opposite sides of the substrate 1 using a vacuum lamination process (see attached diagram). Figure 3 As shown), in particular, this embodiment further optimizes the material and thickness of the dry film 2 as follows: the dry film 2 is preferably made of a photosensitive film with an insulation strength of 50-300kV / mm, a rigidity modulus of 5-10Gpa, and a temperature resistance of 220℃-260℃ (specifically, but not limited to, PI photosensitive film), and the thickness of the dry film 2 is not less than 200μm; this provides solid technical support for successfully producing high copper thickness and micro-pitch insulation circuit patterns in subsequent processes.

[0022] Note: The material of the dry film 2 is controlled in this embodiment because: ① In order to meet the processing requirements of high-copper-thickness circuit patterns (for example, the copper thickness of the circuit pattern needs to reach 200 pm ± 10 pm), the thickness of the dry film 2 in this embodiment is designed to be not less than 200 pm, and in order to better adapt to the dry film with high thickness, the dry film is preferably used in the post-process to make the circuit pattern in the mode of “spraying copper paste and baking and curing combination”. It can be understood that, when spraying, the copper paste will impact the surface of the dry film at high speed, and if the rigidity of the dry film is insufficient, the circuit pattern will be deformed or the bottom will be exposed, and because the linear expansion coefficient of copper is much higher than that of the dry film, if the rigidity of the dry film is insufficient, the high-copper-thickness copper will amplify the thermal stress, thereby causing the dry film to crack. Therefore, in order to avoid the problems caused by insufficient rigidity of the dry film, this embodiment preferably uses a photosensitive adhesive film with high rigidity (rigidity modulus of 5-10 Gpa) to effectively resist mechanical impact and thermal stress, thereby ensuring the pattern precision of the high-copper-thickness circuit pattern and ensuring the process stability. ② Based on the preferred circuit pattern making method in the post-process of this embodiment, if the insulation of the dry film is insufficient, the copper paste may penetrate into the dry film during spraying, causing short circuit between the circuits, or the high-copper-thickness copper paste may cause carbonization or breakdown of the dry film during curing. Therefore, in order to avoid the above problems and to ensure that the circuit pattern has high insulation under the condition of micro-line distance, this embodiment controls the insulation strength of the photosensitive adhesive film (controlled to 50-300 kV / mm) on the basis of controlling the rigidity modulus of the photosensitive adhesive film, that is, the photosensitive adhesive film with high rigidity and good insulation strength is preferably used to ensure the electrical performance and long-term reliability of the circuit pattern. ③ Based on the preferred circuit pattern making method in the post-process of this embodiment, the photosensitive adhesive film is further controlled in terms of temperature resistance value (controlled to 220-260°C) to further ensure the electrical performance and long-term reliability of the circuit pattern. In summary, the photosensitive adhesive film with high rigidity, good insulation strength and high temperature resistance value used in this embodiment is the key to realizing high precision and high reliability of the circuit pattern with high copper thickness and micro-line distance.

[0023] In addition, compared with the prior art, the thickness of the dry film 2 in this embodiment is thicker, so that in actual operation, a plurality of photosensitive adhesive films can be sequentially stacked on the substrate 1 to meet the thickness requirement of the dry film 2.

[0024] S12, expose and develop the dry film 2 according to the operation data to obtain a dry film pattern 20 with a film width of 15-25 pm and a film spacing of not less than 15 pm, which can be referred to in detail in the following Figure 4 .

[0025] It can be understood that, since the dry film 2 used in the embodiment is thicker, the embodiment preferably uses a larger energy exposure process and a longer developing process when exposing and developing the dry film 2, to ensure the exposure quality and developing quality of the thick dry film. For example: ① the exposure energy during the exposure process can be controlled to 300-450 mJ / cm 2 , which effectively avoids the problem of insufficient exposure at the bottom of the dry film 2 due to its excessive thickness, ensuring the exposure quality of the dry film 2. ② The spraying pressure during the developing process is controlled to 0.4-0.6 Kgf / cm 2 , and the spraying time is controlled to 80-120 s. It can be understood that, compared with the conventional developing process, the spraying pressure is 1.5-2.5 Kgf / cm 2 , and the spraying time is about 50-60 s. The embodiment uses a combination of lower spraying pressure and longer spraying time (developing time) to develop, effectively ensuring that the developing liquid penetrates fully and uniformly, thereby ensuring the developing quality of the dry film 2.

[0026] In addition, according to the requirements of the line pattern on the line distance in the post-process, the embodiment further limits the film width of the dry film pattern 20 to 20 μm. As for the film spacing of the dry film pattern 20, it is determined according to the line width design requirements of the line pattern, so the embodiment does not limit it.

[0027] S13, the copper paste is filled in the gap of the dry film pattern 20 in a spraying manner, and after baking and curing, the line pattern sketch 3 is obtained. For details, please refer to FIG. 4. Figure 5 .

[0028] As can be seen from the above, in order to better adapt to the dry film with high film thickness, the embodiment preferably uses a combination of "spraying copper paste and baking and curing" to make the line pattern sketch 3 / line pattern. The preferred processing parameters in the above spraying operation are: the nozzle aperture of the spray gun is controlled to 0.5-1.5 mm, the spray gun distance is controlled to 15-30 cm, the spray gun moving speed is controlled to 0.1-0.5 m / s, the spraying pressure is controlled to 5-20 MPa, the spraying overlap rate is controlled to 50%-70%, and the spraying times are controlled to 2-5 times. It can be understood that, by using the above preferred spraying processing parameters, the layer of the obtained line pattern sketch 3 is continuous and seamless, and the texture is uniform.

[0029] The baking process described above employs a segmented baking technique: first, baking at 50℃~70℃ for 30~50 minutes removes volatiles (bubbles, etc.) from the copper paste, thereby ensuring improved conductivity and structural density of the final circuit pattern; then, baking at 200℃~250℃ for 50~70 minutes solidifies the copper paste while optimizing the conductive network and reducing resistance of the final circuit pattern. Understandably, this segmented baking process ensures a comprehensive improvement in the conductivity, mechanical strength, and surface quality of the circuit pattern.

[0030] S14. By grinding the entire board, the copper thickness of the obtained circuit pattern prototype 3 is reduced to the set copper thickness, thus obtaining the circuit pattern 4 with high copper thickness and micro-pitch (micro-line spacing) insulation. (See attached document.) Figure 6 As shown.

[0031] Understandably, through the above-mentioned grinding, the surface of the obtained circuit pattern 4 facing away from the substrate 1 on the same side of the substrate 1 and the surface of the dry film pattern 20 facing away from the substrate 1 can be on the same horizontal plane. The copper thickness of the circuit pattern 4 can reach, but is not limited to, 200μm±10μm, achieving the characteristic of high copper thickness of the circuit pattern 4. The end face flatness of the circuit pattern 4 is very high, which increases the effective welding area of ​​the circuit pattern 4 and improves the reliability of the product in subsequent use. The dry film pattern 20 realizes and ensures the absolute insulation between the line spacing of the circuit pattern 4, that is, achieves the characteristic of the circuit pattern 4 being insulated with micro-pitch (micro-line spacing).

[0032] As can be seen from the above, compared with the prior art, the high copper thickness micro-pitch insulation circuit fabrication method provided in this application has the following advantages: ① This application innovates the material and thickness of the dry film, the fabrication method of the circuit pattern prototype / circuit pattern, etc., and successfully produces a circuit pattern that combines high copper thickness, micro-pitch (micro-line spacing), and absolute insulation between line spacings. That is, the obtained circuit pattern has excellent electrical performance, precision, reliability, and heat dissipation performance in all aspects, well meeting the needs of the chip market. ② The high copper thickness micro-pitch insulation circuit fabrication method provided in this application not only completely avoids the problems existing in the prior art, but also produces a circuit pattern with very high end-face flatness and a large effective welding area, significantly improving the reliability of the product in subsequent use. ③ The circuit fabrication method provided in this application is applicable to any copper thickness and any line spacing in actual operation, and can guarantee absolute insulation between line spacings, exhibiting high versatility and practicality.

[0033] Example 2:

[0034] Please see the appendix Figure 7 To be continued Figure 11 As shown, this embodiment 2 provides a circuit board manufacturing method, including the following manufacturing steps: S21, the high-copper-thickness micro-pitch insulated circuit manufacturing method provided in the above embodiment 1 is used to manufacture the circuit pattern 4 on the opposite sides of the substrate 1. For the convenience of description, the board manufactured in this step is defined as an intermediate board in this embodiment 2.

[0035] S22, a dry film A5 with a thickness of no less than 200 μm is arranged on the circuit pattern 4 (see FIG. 2), and the dry film A5 is exposed and developed according to the operation data to obtain a dry film pattern A50 (see FIG. 3). Figure 8 Figure 9

[0036] In this embodiment 2, the film width of the dry film pattern A50 is designed to be smaller than that of the dry film pattern 20, which can be understood according to the processing requirements.

[0037] S23, copper paste is filled in the gap of the dry film pattern A50 in a spraying manner, and after baking and curing, a copper column prototype 6 electrically connected with the circuit pattern 4 is obtained (see FIG. 4). Figure 10

[0038] In this embodiment 2, the film width of the dry film pattern A50 is designed to be smaller than that of the dry film pattern 20, which can be understood according to the processing requirements.

[0039] S24, the copper column prototype 6 is reduced to a set copper thickness by whole-board grinding to obtain a copper column 7 (in this embodiment 2, the copper thickness of the copper column 7 is taken as 200 μm as an example, but it is not limited to this, and it can be determined according to the product design requirements), and the circuit board is obtained at this time (see FIG. 5). It can be understood that, by the above grinding, the surface of the obtained copper column 7 on the same side of the intermediate board and away from the circuit pattern 4 is at the same level as the surface of the dry film pattern A50 and away from the circuit pattern 4. As described above, since the end surface flatness of the copper column 7 is very high, the effective soldering area of the copper column 7 is increased, and the reliability of the circuit board product in subsequent use is improved. Figure 11 As can be seen from the above, the circuit board integrated with the circuit pattern with high copper thickness and micro-pitch insulation characteristics and the copper column with high copper thickness is obtained by innovating the circuit board manufacturing method, that is, the obtained circuit board has the advantages of high circuit precision, excellent electrical performance, good reliability, and good heat dissipation performance, which well meets the market demand of chips.

[0040]

[0041] ​​​​Embodiment 3:

[0042] Embodiment 3 provides a circuit board, which is made by the method of making circuit board provided in Embodiment 2.

[0043] Specifically, the circuit board of Embodiment 3 has the following structure: please refer to the attached Figure 11 As described above, the circuit board comprises a substrate 1 made of high-temperature-resistant insulating material and two circuit patterns 4 respectively arranged on the two opposite surfaces of the substrate 1. The copper thickness of the two circuit patterns 4 can reach 200μm±10μm, the line distance is 15-25μm, and the insulation between the line distances is realized by the dry film pattern 20. In addition, the two circuit patterns 4 are also electrically connected. In addition, the two circuit patterns 4 are also respectively provided with copper columns 7 with a copper thickness of 200μm±10μm, and the surface of the copper column 7 is partially coated with an insulating film (i.e. dry film pattern A50).

[0044] It can be understood that the circuit board has the advantages of high circuit precision, excellent electrical performance, good reliability, and good heat dissipation performance, which well meets the market demand of chips.

[0045] Finally, the suffix "A" and the like (such as dry film A) of the component name in the specification are only for easy description and are not used to limit the scope of the patent.

[0046] In the above description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the above description is only a preferred embodiment of the present application, and the present application can be implemented in many other ways different from the description. Therefore, the present application is not limited by the specific implementation disclosed above. Meanwhile, any person skilled in the art can make many possible changes and modifications to the technical solutions disclosed above, or modify them into equivalent embodiments with equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the scope of the technical solutions of the present application, are still within the scope of protection of the present application.

Claims

1. A method for fabricating a high-copper-thickness, micro-pitch insulation circuit, characterized in that: The application relates to a high-copper-thickness micro-spacing insulated circuit manufacturing method. A through hole (10) is drilled on a substrate (1), then dry films (2) with a film thickness not less than 200 mu m are respectively arranged on two opposite surfaces of the substrate (1); The dry films (2) are exposed and developed according to operation data to obtain dry film patterns (20) with a film width of 15-25 mu m and a film spacing not less than 15 mu m; Copper paste is filled in the gaps of the dry film patterns (20) in a spraying mode, and after baking and solidification, a circuit pattern sketch (3) is obtained; The obtained circuit pattern sketch (3) is reduced in copper to a set copper thickness, and a circuit pattern (4) with high copper thickness and micro-spacing insulation is obtained.

2. The method of claim 1, wherein the method is used to fabricate high-copper-thickness, micro-pitch, insulated wiring. The dry film (2) adopts a photosensitive adhesive film with an insulation strength of 50-300 kV / mm, a rigid modulus of 5-10 Gpa and a temperature resistance value of 220 DEG C-260 DEG C.

3. The method of claim 1, wherein the method is used to fabricate high-copper-thickness, micro-pitch, insulated wiring. The spraying processing parameters are as follows: the nozzle aperture of the spray gun is 0.5-1.5 mm, the spray gun distance is 15-30 cm, the spray gun moving speed is 0.1-0.5 m / s, the spraying pressure is 5-20 MPa, the spraying overlap rate is 50%-70%, and the spraying times are 2-5.

4. The method of claim 1, wherein the method is used to fabricate high-copper-thickness, micro-pitch, insulated wiring. The baking adopts a sectional baking process, that is, first, the copper paste is baked at 50 DEG C-70 DEG C for 30-50 min to remove volatile matters in the copper paste; and then the copper paste is baked at 200 DEG C-250 DEG C for 50-70 min to realize solidification of the copper paste.

5. The method for fabricating a high-copper-thickness, micro-pitch insulation circuit according to claim 1, characterized in that: The obtained circuit pattern (4) is ground to make a surface of the circuit pattern (4) opposite to the substrate (1) and a surface of the dry film pattern (20) opposite to the substrate (1) be in the same horizontal plane.

6. The method for fabricating a high-copper-thickness micro-pitch insulation circuit according to claim 1, characterized in that: The substrate (1) is made of a high-temperature-resistant insulating material; and the copper thickness of the circuit pattern (4) reaches 200 mu m+ / -10 mu m.

7. A method of manufacturing a wiring board, characterized by: The application further relates to a circuit board manufacturing method. The application further relates to a circuit board manufacturing method. The application further relates to a circuit board manufacturing method. The application further relates to a circuit board manufacturing method. The application further relates to a circuit board manufacturing method.

8. The method of manufacturing a circuit board according to claim 7, wherein: The application further relates to a circuit board manufacturing method.

9. A wiring board, characterized by: The application further relates to a circuit board manufacturing method.

Images