Circuit board and manufacturing method thereof

Abstract

The invention discloses a circuit board and a manufacturing method thereof, and the method comprises the following steps: firstly, checking whether a PCB is qualified or not, carrying out the cutting of the qualified PCB, then drilling a hole of which the position and size need to meet the requirements in the material drilled in the step 1 through a drilling machine, and carrying out the machining of the hole. The method comprises the following steps of: removing an oxide layer and drilling burrs on the surface of the perforated PCB in the step 2 in a state that the perforated PCB is polished and brushed by a board polishing machine, performing PTH (Plating Through Hole) copper deposition treatment on the PCB treated by the board polishing machine in the step 3, and checking the drilling position and the hole diameter of the perforated PCB by using a red film and a needle gauge. The method has the following advantages that no cavity or crack exists in the hole, the surface of the hole is flush with copper, the quality defects of cavities, cracks and bubbles in a conventional ink resin plug hole are overcome, and the method is simple in structure and easy to machine and manufacture.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit boards, and in particular to a circuit board and a manufacturing method thereof. Background Art

[0002] With the rapid development of electronic information technology, components are gradually miniaturized, the wiring density of circuit boards is gradually increasing, the image design area is also constantly decreasing, and the product reliability requirements are getting higher and higher. In order to adapt to this development trend, the design and manufacture of PCBs are constantly updating design concepts and process methods to achieve high precision and high reliability requirements. Among them, the process of resin plugging has been more and more widely used in the PCB industry in recent years, especially in some products with high number of layers and thicker boards. People hope to use resin plugging to solve a series of problems that cannot be solved by using green oil plugging or pressing filling resin. However, due to the characteristics of the resin itself used in this process, the resin plugging hole board is prone to blistering at the resin plugging hole position during FQC reflow soldering. Therefore, a circuit board and a method for making it are provided to solve the above problems. Summary of the invention

[0003] The technical solution adopted by the present invention to solve the technical problem is: a method for manufacturing a circuit board, which comprises the following steps:

[0004] Step 1: First, check whether the PCB board is qualified, and cut the qualified PCB board;

[0005] Step 2: Then use a drill to drill holes in the material opened in step 1, and use red film and needle gauge to check the drilling position and hole diameter of the PCB board with holes.

[0006] Step 3: Grind the PCB board with holes in step 2 on a grinding machine to remove the oxide layer and drilling burrs on the surface of the board;

[0007] Step 4: The PCB board processed by the grinding machine in step 3 is subjected to PTH copper deposition treatment, and the PCB board after PTH copper deposition is resin plugged through VCP, and the PCB board with the resin plugged hole is subjected to grinding and brushing treatment by the grinding machine in step 3 again, and then copper deposition treatment is performed, and the circuit pattern is drawn on the PCB board after copper deposition treatment;

[0008] Step 5: The PCB board with the circuit pattern completed in step 4 is electroplated throughout the board, and then etched. The etched PCB board is then green-painted, formed, and electrically tested to produce the final circuit board.

[0009] As a preferred technical solution of the present invention, in step one, cutting is the process of sawing a large piece of material into small pieces by machine according to different board making requirements, and in step five, electroplating is to use acid copper electroplating method to thicken the circuit copper and hole wall copper to the required thickness of the PCB board that has completed the pattern transfer process, and use the tin plating layer as a protective layer for etching in the next process.

[0010] As a preferred technical solution of the present invention, in step one, the inspection of the PCB board includes copper foil oxidation, scratches, copper foil blistering, copper foil thickness, board thickness, thermal stress impact test, and copper foil tension.

[0011] As a preferred technical solution of the present invention, in step 2, drilling holes in the PCB board is to achieve conduction between layers and component soldering, to make positioning or alignment holes for subsequent processing, and to check the position and aperture of the drilled holes with red film and needle gauge to ensure that there are no extra or insufficient holes.

[0012] As a preferred technical solution of the present invention, in step four, the step of drawing the circuit graphics includes grinding the plate, silk screen printing, baking, exposure, development, and circuit inspection. The silk screen printing controls the air purity, ink viscosity, and the ratio of ink to oil water. The baking controls the time and temperature. The exposure controls the exposure energy. The development controls the proportion of the liquid medicine and the liquid medicine temperature inspection control.

[0013] As a preferred technical solution of the present invention, the exposure is that the ultraviolet rays of the exposure machine pass through the negative film to make part of the pattern on the film sensitive, so that the pattern is transferred to the copper plate, and the development is to remove the ink of the unexposed part and leave the sensitive part. The principle of development is that the photosensitive material in the unexposed part does not undergo polymerization reaction and dissolves when encountering the developer, while the polymerized photosensitive material remains on the plate surface.

[0014] As a preferred technical solution of the present invention, in step 4, the PTH copper deposition treatment steps include bulking, desmearing, pickling, hole filling, micro-etching, pre-preg, activation, copper deposition, and drying.

[0015] As a preferred technical solution of the present invention, the desmearing process is mainly used to deal with the instantaneous high temperature generated when drilling on the PCB board. The epoxy glass substrate is a poor conductor, and heat accumulates highly during drilling. The surface temperature of the hole wall exceeds the glass transition temperature of the epoxy resin, resulting in the epoxy resin flowing along the surface of the hole wall to produce a thin layer of smearing.

[0016] As a preferred technical solution of the present invention, the copper deposition is carried out by self-catalytic chemical oxidation and reduction reaction. 2+ The ions are reduced to metallic copper by electrons, and the reducing agent releases electrons, which are used for hole metallization to complete the connection of the wires between the layers of the PCB board.

[0017] A circuit board comprises: a base board, a copper foil layer, an adhesive layer, and a protective layer. The copper foil layer is attached to the upper and lower sides of the base board, the copper foil layer is coated with an adhesive layer on the side opposite to the base board, and the protective layer is attached to the outside of the adhesive layer. The base board, the copper foil layer, the adhesive layer, and the protective layer are drilled with resin plug holes, and the base board, the copper foil layer, the adhesive layer, and the protective layer are provided with copper holes.

[0018] The present invention has the following advantages: the circuit board resin plugging hole of the present invention can achieve no voids or cracks in the hole, and the surface is flush with the copper, which solves the quality defects of voids, cracks and bubbles in conventional ink resin plugging holes, has a simple structure and is easy to process and manufacture.

[0019] Through the copper electroplating process, the contact area between the drilled pad and the pin of the plug-in device can be expanded, which can not only enhance the welding effect between the plug-in device and the through-hole pad, but also reduce the parasitic resistance between the plug-in device and the drilled pad, thereby ensuring the transmission integrity of the signal flowing through the plug-in device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the circuit board manufacturing process of the preferred embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the electroplating principle structure of a preferred embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the circuit board structure of the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Many specific details are explained in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0024] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Please refer to Figure 1-Figure 2 The present invention provides a method for manufacturing a circuit board, comprising the following steps:

[0026] Step 1: First, check whether the PCB board is qualified, and cut the qualified PCB board;

[0027] Step 2: Then use a drill to drill holes in the material opened in step 1, and use red film and needle gauge to check the drilling position and hole diameter of the PCB board with holes.

[0028] Step 3: Grind the PCB board with holes in step 2 on a grinding machine to remove the oxide layer and drilling burrs on the surface of the board;

[0029] Step 4: After the PCB board has been processed by the grinding machine in step 3, it is subjected to PTH copper plating treatment, and the PCB board after PTH copper plating is resin plugged through VCP, and the PCB board with the resin plugged hole is again subjected to grinding and brushing by the grinding machine in step 3, and then copper plating treatment is carried out. The circuit pattern is drawn on the PCB board after the copper plating treatment. Before resin plugging, the resin before plugging needs to be thawed 3 hours in advance.

[0030] Step 5: The PCB board with the circuit pattern completed in step 4 is electroplated on the whole board, and then etched. The etched PCB board is then green-oiled, formed, and electrically tested. The qualified finished product is the final circuit board. The green oil is on the mesh with a negative pattern. A proper amount of green oil ink is squeezed out with a scraper, and a positive pattern is formed through the mesh, which is printed on the base surface or copper surface. The molding is through the gong plate. The CNC gongs the board into the required shape according to the data input into the computer, and a small batch trial production is carried out. The shape size, white oil, green oil, aperture, circuit, warpage, etc. of the formed product are tested for qualification, and the baking parameters of the PCB board are: 80℃ / 30min+110℃ / 30min+150℃ / 60min.

[0031] In step one, cutting is the process of sawing a large piece of material into small pieces by machine according to different board making requirements. The edges and corners of the board after cutting are sharp, which can easily scratch your hands and cause scratches between the boards. Therefore, the corners are rounded with a fillet machine after cutting. The inspection of PCB board includes copper foil oxidation, scratches, copper foil blistering, copper foil thickness, board thickness, thermal stress impact test, and copper foil tension.

[0032] Among them, drilling holes in PCB boards is to achieve conduction between layers and component soldering, to make positioning or alignment holes for subsequent processing, and to check the position and aperture of the drilled holes through red film and needle gauge to ensure that there are no multiple or few holes. The steps of drawing circuit graphics include grinding, silk screen printing, baking, exposure, development, and circuit inspection. The silk screen controls air purity, ink viscosity, and the ratio of ink to oil water. The baking controls time and temperature, the exposure controls exposure energy, the development controls the ratio of liquid medicine, and the liquid medicine temperature inspection control. Exposure is the ultraviolet rays of the exposure machine passing through the film to make part of the pattern on the film sensitive, so that the pattern is transferred to the copper plate. The development is to remove the ink of the unexposed part and leave the sensitive part. The principle of development is that the photosensitive material of the unexposed part does not undergo polymerization reaction, and is dissolved when it encounters the developer, while the polymerized photosensitive material remains on the board.

[0033] Among them, the PTH copper plating treatment steps include bulking, desmearing, pickling, hole filling, micro-etching, pre-preg, activation, copper plating, and drying. The desmearing is mainly used to deal with the instantaneous high temperature generated when the PCB board is drilled. The epoxy glass substrate is a poor conductor. The heat is highly accumulated during drilling. The surface temperature of the hole wall exceeds the glass transition temperature of the epoxy resin, resulting in the epoxy resin flowing along the surface of the hole wall, producing a thin layer of smear. The copper plating is through self-catalytic chemical oxidation and reduction reaction. In the process of chemical copper plating, Cu 2+ The ions are reduced to metallic copper by electrons, and the reducing agent releases electrons, which are used for hole metallization to complete the connection of the wires between the layers of the PCB board.

[0034] Combination Figure 2 As shown, electroplating is to use acid copper electroplating to thicken the circuit copper and hole wall copper to the required thickness of the PCB board that has completed the pattern transfer process, and use the tin plating layer as a protective layer for the next etching process. The etching steps include film stripping, water washing, grinding, high-pressure water washing, etching, high-pressure water washing, drying, tin stripping, strong wind drying, and inspection. Etching is to etch the copper surface by the reaction of etching liquid and ink-coated copper surface. The circuit pattern is retained due to the anti-corrosion layer. The tin layer on the circuit pattern is removed to finally obtain the circuit pattern. The principle of electroplating is that the main components of the copper plating solution are CuSO4 and H2SO4, and the following reactions occur at the anode and cathode under the direct voltage: cathode: Cu 2+ +2e-Cu, anode Cu-2e-Cu 2+ .

[0035] Combination Figure 3As shown, one kind of circuit board includes: a base board 1, a copper foil layer 2, an adhesive layer 3, and a protective layer 4. The copper foil layer 2 is attached to the upper and lower sides of the base board 1, the adhesive layer 3 is coated on the side of the copper foil layer 2 opposite to the base board 1, and the protective layer 4 is attached to the outside of the adhesive layer 3. The base board 1, the copper foil layer 2, the adhesive layer 3, and the protective layer 4 are drilled with resin plug holes 5, and the base board 1, the copper foil layer 2, the adhesive layer 3, and the protective layer 4 are provided with copper holes 6.

[0036] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0037] Other parts of the present invention not described in detail belong to the prior art and will not be described in detail here.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that: The following steps are involved: Step 1: First, check whether the PCB board is qualified, and cut the qualified PCB board; Step 2: Then use a drill to drill holes in the material opened in step 1, and use red film and needle gauge to check the drilling position and hole diameter of the PCB board with holes. Step 3: Grind the PCB board with holes in step 2 on a grinding machine to remove the oxide layer and drilling burrs on the surface of the board; Step 4: The PCB board processed by the grinding machine in step 3 is subjected to PTH copper deposition treatment, and the PCB board after PTH copper deposition is resin plugged through VCP, and the PCB board with the resin plugged hole is subjected to grinding and brushing treatment by the grinding machine in step 3 again, and then copper deposition treatment is performed, and the circuit pattern is drawn on the PCB board after copper deposition treatment; Step 5: The PCB board with the circuit pattern completed in step 4 is electroplated throughout the board, and then etched. The etched PCB board is then green-painted, formed, and electrically tested to produce the final circuit board.

2. A method for manufacturing a circuit board according to claim 1, characterized in that: In step one, cutting is the process of sawing a large piece of material into small pieces by machine according to different board making requirements. In step five, electroplating is to use acid copper electroplating method to thicken the circuit copper and hole wall copper to the required thickness of the PCB board that has completed the pattern transfer process, and use the tin plating layer as a protective layer for etching in the next process.

3. A method for manufacturing a circuit board according to claim 1, characterized in that: In step one, the inspection of PCB board includes copper foil oxidation, scratches, copper foil blistering, copper foil thickness, board thickness, thermal stress impact test, and copper foil tension.

4. A method for manufacturing a circuit board according to claim 1, characterized in that: In step 2, drilling holes in the PCB board is to achieve conduction between layers and component soldering, to make positioning or alignment holes for subsequent processing, and to check the position and aperture of the drilled holes with red film and needle gauge to ensure that there are no extra or insufficient holes.

5. A method for manufacturing a circuit board according to claim 1, characterized in that: In step four, the steps of drawing circuit graphics include grinding, silk screen printing, baking, exposure, development, and circuit inspection. The silk screen printing controls air purity, ink viscosity, and the ratio of ink to oil water. The baking controls time and temperature. The exposure controls exposure energy. The development controls the proportion of the solution and the temperature of the solution.

6. A method for manufacturing a circuit board as claimed in claim 5, characterized in that: The exposure is that the ultraviolet rays of the exposure machine pass through the negative to make part of the pattern on the film sensitive to light, so that the pattern is transferred to the copper plate. The development is to remove the ink of the unexposed part and leave the sensitive part. The principle of development is that the photosensitive material in the unexposed part does not undergo polymerization reaction and dissolves when encountering the developer, while the polymerized photosensitive material remains on the plate surface.

7. A method for manufacturing a circuit board according to claim 1, characterized in that: In step 4, the PTH copper deposition treatment steps include bulking, desmearing, pickling, hole filling, micro-etching, pre-preg, activation, copper deposition, and drying.

8. A method for manufacturing a circuit board according to claim 7, characterized in that: The desmearing process is mainly used to deal with the instantaneous high temperature generated when drilling holes in PCB boards. The epoxy glass substrate is a poor conductor, and heat accumulates greatly during drilling. The surface temperature of the hole wall exceeds the glass transition temperature of the epoxy resin, resulting in the epoxy resin flowing along the surface of the hole wall, producing a thin layer of smearing.

9. A method for manufacturing a circuit board according to claim 7, characterized in that: The copper deposition is carried out by self-catalytic chemical oxidation and reduction reaction. 2+ The ions are reduced to metallic copper by electrons, and the reducing agent releases electrons, which are used for hole metallization to complete the connection of the wires between the layers of the PCB board.

10. A circuit board, characterized in that: include: A base board, a copper foil layer, an adhesive layer, and a protective layer. The copper foil layer is attached to the upper and lower sides of the base board. The copper foil layer is coated with an adhesive layer on the side opposite to the base board. The protective layer is attached to the outside of the adhesive layer. The base board, the copper foil layer, the adhesive layer, and the protective layer are drilled with resin plug holes. The base board, the copper foil layer, the adhesive layer, and the protective layer are provided with copper holes.

Images