Arbitrary interconnection thick copper circuit board blind hole manufacturing method and device

Abstract

The embodiment of the invention relates to a method and a device for manufacturing blind holes of any interconnected thick copper circuit board. The method comprises the following steps of: forming a thick copper window in a target windowing area of a copper plate through an etching method; and performing laser drilling in the windowing area through a winding burning method to manufacture the blind hole. According to the scheme, a mechanical blind hole process is replaced by a laser blind hole process, so that bottom copper does not need to be punched at the connecting position of the blind hole and the bottom layer, the conduction effect is ensured, the mechanical blind hole is prevented from damaging the thickness of a medium, and the electromagnetic effect of the motor is ensured.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of PCB manufacturing, and in particular to a method and device for manufacturing blind vias in an arbitrary interconnected thick copper circuit board. Background Art

[0002] The circuit board is an indispensable part of modern electrical equipment, and it undertakes the important function of transmitting and controlling signals. The production capacity of HDI laser blind holes on the market is between 0.075mm and 0.2mm, and the maximum thickness of copper punched by the circuit board laser drilling machine is generally 12 microns. This product is a circuit board motor product. The electromagnetic core is a circuit board winding structure, replacing the traditional motor core winding mode. The circuit board motor product winding design is a blind hole, and the line specification is 0.8mm. The solid blind hole conduction design must be equivalent to the surface line size specification to meet the conductivity. Otherwise, the resistance is too large and the circuit board motor product heats up and overloads. Since the laser blind hole process cannot fully meet the requirements, the solid current design products all use mechanical blind hole production technology. The mechanical production of blind holes for this product also has some defects or limitations. The mechanical blind hole will drill off a part of the insulation layer, thinning the insulating medium layer, affecting the electromagnetic effect of the motor, which is inconsistent with the original product design; in addition, the mechanical blind hole process cannot produce blind holes within 0.1mm, and it is difficult to produce high-precision circuit boards. Summary of the invention

[0003] In view of the above problems, the embodiments of the present invention provide a method and device for making blind vias in any interconnected thick copper circuit board, which are used to solve the problems of high production cost, low production efficiency and extremely low yield rate in the existing local gold plating.

[0004] According to one aspect of an embodiment of the present invention, a method for making blind vias in an arbitrary interconnected thick copper circuit board is provided, the method comprising: Opening a thick copper window in a target window opening area of ​​the copper plate by etching, wherein the etching method sequentially includes a film pasting process, an exposure process, a window opening and developing process, an etching process, and a film stripping process; The blind holes are made by laser drilling in the window opening area by the burning-around method.

[0005] In some optional embodiments, the step of performing laser drilling to form blind holes in the window opening area by the burn-around method specifically includes: A laser area is arranged outside the target window opening area of ​​the copper plate, wherein the laser area is larger than the target window opening area and covers the target window opening area; The laser beam performs circumferential ablation along the laser area until the substrate in the laser area is completely ablated.

[0006] In some optional embodiments, the step of performing circumferential ablation along the laser region by using a laser beam specifically includes: The laser beam is moved along the X and Y axes to ablate around the laser area, wherein the pulse width of the laser beam is 15 μm and the energy is 30.5 mj.

[0007] In some optional embodiments, the diameter of the target window area is 0.4 mm, and the diameter of the laser area is 0.425 mm.

[0008] In some optional embodiments, the film attaching process specifically includes: A photosensitive dry film is pasted on a copper plate at a film pasting temperature of 115°C ± 10°C, a film pasting pressure of 8KG / CM, and a speed of 2.3m / min to form an anti-corrosion layer on the copper plate; wherein the photosensitive dry film is DuPont DI8325.

[0009] In some optional embodiments, the exposure process specifically includes: The photosensitive dry film in the area outside the first window area of ​​the copper plate is exposed and cured, and the exposure energy is between 250mj and 300mj.

[0010] In some optional embodiments, the window opening and developing process specifically includes: The first window area is developed with 1.2% sodium carbonate at a developing pressure of 20 PSI to 30 PSI for 55 seconds to 65 seconds; After the development is completed, the residual solution on the copper plate is cleaned with clean water and air-dried.

[0011] In some optional embodiments, the etching process specifically includes: The copper plate is provided with a target window opening area, the target window opening area is larger than the first window opening area and the target window opening area completely covers the first window opening area; After etching the copper in the first window area by face etching, face etching and side etching are performed in the target window area to form a thick copper window in the target window area.

[0012] In some optional embodiments, the film stripping process specifically includes: After the etching process is completed, the photosensitive dry film that is exposed and cured on the surface of the copper plate is removed by sodium hydroxide solution to expose the copper surface.

[0013] According to another aspect of an embodiment of the present invention, a device for making blind holes in an arbitrary interconnected thick copper circuit board is provided, characterized in that the device is used to execute the above-mentioned method for making blind holes in an arbitrary interconnected thick copper circuit board to make a printed circuit board.

[0014] The method and device for making blind holes in any interconnected thick copper circuit board of the present invention have the beneficial effects that: the present invention uses an etching method to open thick copper windows in the target window opening area of ​​the copper plate; and uses a burning method to perform laser drilling to make blind holes in the window opening area. Through the above scheme, the laser blind hole process replaces the mechanical blind hole process, which not only can achieve the connection between the blind hole and the bottom layer without drilling through the bottom copper to ensure the conduction effect, but also avoids the mechanical blind hole from damaging the dielectric thickness, while ensuring the electromagnetic effect of the motor.

[0015] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings: Figure 1 A schematic flow chart of a method for making blind vias in an arbitrary interconnected thick copper circuit board according to Embodiment 1 of the present invention is shown; Figure 2 A schematic diagram of a PCB board in which blind holes are made by laser drilling in the window opening area by a wrap-around method according to Example 2 of the present invention is shown; Figure 3 A schematic diagram of the process of opening a thick copper window in a target window opening area of ​​a copper plate by etching according to Example 3 provided by the present invention is shown. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0018] Embodiment 1: Figure 1 The first embodiment of a method for making blind holes in a thick copper circuit board with arbitrary interconnection is shown. The present invention aims to replace the existing mechanical blind hole process with a laser blind hole process to achieve the connection between the blind hole and the bottom layer without punching through the bottom copper to ensure the conduction effect, and avoid mechanical blind holes damaging the dielectric thickness, while ensuring the electromagnetic effect of the motor. Specifically, a method for making blind holes in a thick copper circuit board with arbitrary interconnection of the present invention includes: 110, a thick copper window is opened in the target window area of ​​the copper plate by etching. In step 110, the etching method includes a film pasting process, an exposure process, a window development process, an etching process, and a film stripping process in sequence; the film pasting process specifically includes: pasting a photosensitive dry film on the copper plate at a film pasting temperature of 115°C ± 10°C, a film pasting pressure of 8KG / CM, and a speed of 2.3m / min to form an anti-corrosion layer on the copper plate; wherein the photosensitive dry film is DuPont DI8325. The exposure process specifically includes: exposing and curing the photosensitive dry film in the area other than the first window area of ​​the copper plate, and the exposure energy is between 250mj and 300mj. The window development process specifically includes: using a concentration of 1.2% sodium carbonate on the first window area, developing for 55 seconds to 65 seconds at a development pressure of 20PSI ~30PSI; after the development is completed, the residual medicine on the copper plate is washed with clean water and air-dried. The etching process specifically includes: setting a target window area on the copper plate, the target window area is larger than the first window area and the target window area completely covers the first window area; after etching the copper in the first window area by surface etching, etching the target window area by surface etching and side etching, and forming a thick copper window in the target window area. The film stripping process specifically includes: after completing the etching process, exposing and curing the photosensitive dry film on the surface of the copper plate, and stripping it by sodium hydroxide solution to expose the copper surface.

[0019] 120, laser drilling is performed in the window opening area to form a blind hole by a circumferential burning method. In step 120, a laser area is set outside the target window opening area of ​​the copper plate, the laser area is larger than the target window opening area and the laser area covers the target window opening area; a laser beam is used to circumferentially ablate along the laser area until the substrate in the laser area is completely ablated.

[0020] The present invention uses an etching method to open a thick copper window in the target window opening area of ​​the copper plate; and uses a winding burning method to perform laser drilling to make a blind hole in the window opening area. Through the above scheme, the laser blind hole process replaces the mechanical blind hole process, which not only can achieve the blind hole and the bottom connection position without drilling through the bottom copper to ensure the conduction effect, but also avoids the mechanical blind hole from damaging the dielectric thickness, while ensuring the electromagnetic effect of the motor.

[0021] Embodiment 2: Figure 2 An embodiment of laser drilling to produce blind holes in the window opening area by a circumferential burning method is shown. This embodiment specifically uses a circumferential burning method to perform laser drilling to produce blind holes in the window opening area, specifically including: setting a laser area outside the target window opening area of ​​the copper plate, the laser area is larger than the target window opening area and the laser area covers the target window opening area; and performing circumferential ablation along the laser area by a laser beam until the substrate in the laser area is completely ablated.

[0022] In this embodiment, the blind hole is produced by laser drilling in the window area by the burn-around method. Specifically, the laser equipment adopts a burn-around program designed around the blind hole area, so that the laser beam surrounds the laser area of ​​the blind hole and ablates it in sequence. Figure 2 As shown, 210 is the laser area, 220 is the laser beam, 230 is the surface copper layer of the copper plate, 240 is the base layer of the copper plate, and 250 is the inner copper layer of the copper plate. The laser beam ablates the base layer of the copper plate around the laser area to form a blind hole.

[0023] In one implementation of the above embodiment, the laser beam is used to perform circumferential ablation along the laser area, specifically including: when making an extra-large blind hole, a plurality of laser beams are used for ablation when one laser beam cannot complete the blind hole. In this solution, the laser beam is moved along the X and Y axis moments to make the laser beam ablate around the laser area, wherein the pulse width of the laser beam is 15 μm and the energy is 30.5 mj. The number of pulses can be determined according to the size of the laser area. For example, when the laser area is 0.425 mm, the number of pulses can be 6 times.

[0024] In the prior art, since blind hole drilling and copper window opening are two different production processes, there is always an error in alignment. If there is an error, the copper surface and the substrate hole will be misaligned, and the electroplated copper connecting the two will be at risk of breaking. This solution adopts a burn-in diameter design that is larger than the copper window diameter. The burn-in diameter is the laser area, and the copper window diameter is the target area; it is 0.025mm larger than the finished copper window diameter. Even if there is an error in ablation alignment, the ablated diameter surface is larger than the actual diameter, thereby ensuring that the burn-in laser beam covers the entire window substrate surface to avoid the step problem between the substrate and the copper surface; solving the technical problems existing in the prior art. In a specific example, the diameter of the target window area is 0.4mm, and the diameter of the laser area is 0.425mm.

[0025] Embodiment 3: Figure 3 An embodiment of opening a thick copper window in a target window opening area of ​​a copper plate by etching is shown. This embodiment specifically includes: 310, film pasting process; in step 310, the film pasting process specifically includes: pasting a photosensitive dry film on the copper plate at a film pasting temperature of 115℃±10℃, a film pasting pressure of 8KG / CM, and a speed of 2.3m / min to form an anti-corrosion layer on the copper plate; wherein the photosensitive dry film is DuPont DI8325.

[0026] 320, exposure process. In step 320, the exposure process specifically includes: exposing and curing the photosensitive dry film in the area outside the first window area of ​​the copper plate, and the exposure energy is between 250mj-300mj.

[0027] 330, window development process, in step 330, the window development process specifically includes: using 1.2% sodium carbonate concentration on the first window area, developing for 55 seconds to 65 seconds at a developing pressure of 20PSI ~30PSI; after the development is completed, the residual solution on the copper plate is washed with clean water, and air-dried.

[0028] 340, etching process. In step 340, the etching process specifically includes: setting a target window area on the copper plate, the target window area is larger than the first window area and the target window area completely covers the first window area; after etching the copper in the first window area by surface etching, etching the target window area by surface etching and side etching, and forming a thick copper window in the target window area.

[0029] 350, film stripping process, in step 350, the film stripping process specifically includes: after the etching process is completed, the photosensitive dry film exposed and cured on the surface of the copper plate is stripped away by sodium hydroxide solution to expose the copper surface.

[0030] In this embodiment, since the photosensitive dry film is prone to dry film shrinkage during exposure, specifically, the exposure window is pre-shrunk by 35μm on one side for 35μm copper thickness, and the exposure window is pre-shrunk by 55μm on one side for 70μm thickness. In order to solve the technical problem of exposure pre-shrinkage, the present invention adopts that in the exposure process, the area outside the first window area is first exposed and cured. In this process, the target window area is larger than the first window area and the target window area completely covers the first window area. The subsequent window development is also made according to the first window area to avoid the blind hole size becoming larger during etching.

[0031] In one example, the first windowing area and the target windowing area are circular structures with the same center, the target windowing area is larger than the diameter of the first windowing area, and the diameter difference between the target windowing area and the first windowing area can be set according to the dry film pre-shrinkage range. For example, if the 35μm copper thickness exposure windowing is pre-shrunk by 35μm on one side, the diameter of the first windowing area can be 0.33mm, and the diameter of the target windowing area can be 0.4mm. If the 70μm thick exposure windowing is pre-shrunk by 55μm on one side, the diameter of the first windowing area can be 0.29mm, and the diameter of the target windowing area can be 0.4mm.

[0032] In the etching process, after the copper in the first window area is etched by surface etching, the target window area is etched by surface etching and side etching, and a thick copper window is formed in the target window area. This process etches out the surface copper in the target window area of ​​the surface copper of the copper plate. The present application etches the copper in the first window area by surface etching first. Then, other areas in the target window area are etched by surface etching and side etching. It can be achieved that the thick copper on the surface of the copper plate is completely etched out, and the blind hole is controlled within the target window position.

[0033] In an embodiment, a target window position is etched out of the surface thick copper of the copper plate by an etching method, thereby creating laser conditions for a subsequent laser blind hole process.

[0034] Embodiment 4: According to another aspect of an embodiment of the present invention, there is provided a device for making blind holes in an arbitrary interconnected thick copper circuit board, characterized in that the device is used to execute the method for making blind holes in an arbitrary interconnected thick copper circuit board described in Examples 1-3 to make a printed circuit board. The present invention uses an etching method to open thick copper windows in the target window opening area of ​​the copper plate; and uses a burning method to perform laser drilling to make blind holes in the window opening area. Through the above scheme, the laser blind hole process is used to replace the mechanical blind hole process, which not only can ensure the conduction effect without punching through the bottom copper at the connection position between the blind hole and the bottom layer, but also avoids the mechanical blind hole from damaging the dielectric thickness, while ensuring the electromagnetic effect of the motor.

[0035] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

[0036] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0037] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present invention may be implemented with the aid of hardware comprising several different elements and with the aid of appropriately programmed computers. In a unit claim that lists several systems, several of these systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A method for making blind vias in arbitrary interconnected thick copper circuit boards, characterized in that: The method comprises: Opening a thick copper window in a target window opening area of ​​the copper plate by etching, wherein the etching method sequentially includes a film pasting process, an exposure process, a window opening and developing process, an etching process, and a film stripping process; The blind holes are made by laser drilling in the window opening area by the burning-around method.

2. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 1, characterized in that: The method of laser drilling a blind hole in the window opening area by the burning-around method specifically includes: A laser area is arranged outside the target window opening area of ​​the copper plate, wherein the laser area is larger than the target window opening area and covers the target window opening area; The laser beam performs circumferential ablation along the laser area until the substrate in the laser area is completely ablated.

3. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 2, characterized in that: The method of performing circumferential ablation along the laser area by using a laser beam specifically includes: The laser beam is moved along the X and Y axes to ablate around the laser area, wherein the pulse width of the laser beam is 15 μm and the energy is 30.5 mj.

4. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 3, characterized in that: The diameter of the target window area is 0.4 mm, and the diameter of the laser area is 0.425 mm.

5. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 1, characterized in that: The film pasting process specifically includes: A photosensitive dry film is pasted on a copper plate at a film pasting temperature of 115°C ± 10°C, a film pasting pressure of 8KG / CM, and a speed of 2.3m / min to form an anti-corrosion layer on the copper plate; wherein the photosensitive dry film is DuPont DI8325.

6. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 5, characterized in that: The exposure process specifically includes: The photosensitive dry film in the area outside the first window area of ​​the copper plate is exposed and cured, and the exposure energy is between 250mj and 300mj.

7. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 6, characterized in that: The window opening and developing process specifically includes: The first window area is developed with 1.2% sodium carbonate at a developing pressure of 20 PSI to 30 PSI for 55 seconds to 65 seconds; After the development is completed, the residual solution on the copper plate is cleaned with clean water and air-dried.

8. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 7, characterized in that: The etching process specifically includes: The copper plate is provided with a target window opening area, the target window opening area is larger than the first window opening area and the target window opening area completely covers the first window opening area; After etching the copper in the first window area by face etching, face etching and side etching are performed in the target window area to form a thick copper window in the target window area.

9. The method for making blind vias in arbitrary interconnected thick copper circuit boards according to claim 8, characterized in that: The film stripping process specifically includes: After the etching process is completed, the photosensitive dry film that is exposed and cured on the surface of the copper plate is removed by sodium hydroxide solution to expose the copper surface.

10. A device for making blind vias in arbitrary interconnected thick copper circuit boards, characterized in that: The device is used to execute the method for making blind holes in any interconnected thick copper circuit board as described in any one of claims 1 to 9 to make a printed circuit board.

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