Manufacturing method of thick copper circuit board and thick copper circuit board

Abstract

The invention discloses a manufacturing method of a thick copper circuit board, and discloses the thick copper circuit board, and the manufacturing method of the thick copper circuit board comprises the following steps: 1, obtaining a substrate, and carrying out the full-board electroplating processing of the substrate, so as to form a thick copper layer on the substrate; 2, manufacturing a local gold plating pattern on the thick copper layer through dry film pasting, exposure and development in sequence; 3, the whole thick copper layer serves as a conductor, and nickel electroplating and gold electroplating are sequentially carried out on the position of the local gold electroplating pattern; 4, the thick copper layer is subjected to film stripping through alkaline film stripping liquid; 5, etching the thick copper layer by adopting an etching solution, and manufacturing an inner layer circuit on the thick copper layer; the whole thick copper layer is used as a conductor to carry out nickel electroplating and gold electroplating, so that the requirement of designing and removing a gold electroplating lead on the copper layer in the traditional process is avoided, the mechanical damage of the circuit board, which is easily caused when the lead is removed, is avoided, and the yield of the circuit board is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board, in particular to a thick copper circuit board manufacturing method and thick copper circuit board. BACKGROUND

[0002] The circuit board, namely PCB, has at least one conductive pattern and is provided with holes and grooves to realize the mutual connection between electronic components, and is almost the basis of all electronic products. The circuit board is divided into multiple layers and single layer. The multi-layer PCB refers to the printed board with two or more layers, which is composed of connecting wires on the insulating substrate and solder pads for assembling electronic components, and has the functions of conducting lines between layers and insulating each other. The main purpose of thick copper plating is to ensure that there is a thick copper plating layer in the hole to ensure that the resistance value is within the range required by the process.

[0003] The existing circuit board needs to design an electro-gold lead on the copper layer before electroplating nickel and electroplating gold. After completing the electroplating gold, the electro-gold lead needs to be removed. When removing the electro-gold lead, the circuit board is easily damaged, resulting in a low yield of the circuit board. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a thick copper circuit board manufacturing method, which can complete the electroplating nickel and electroplating gold process without designing an electro-gold lead, thereby improving the yield of the circuit board.

[0005] The present application also provides a thick copper circuit board obtained by the above-mentioned thick copper circuit board manufacturing method.

[0006] The thick copper circuit board manufacturing method according to the first aspect of the present application comprises the following steps:

[0007] Step 1: obtaining a substrate, and performing full-plate electroplating treatment on the substrate to form a thick copper layer on the substrate;

[0008] Step 2: sequentially making a local electro-gold pattern on the thick copper layer by pasting dry film, exposure and development;

[0009] Step 3: using the entire thick copper layer as a conductor to sequentially perform electroplating nickel and electroplating gold at the position of the local electro-gold pattern;

[0010] Step 4: using an alkaline film stripping solution to strip the film on the thick copper layer;

[0011] Step 5: etching the thick copper layer by using an etching solution to make inner layer lines on the thick copper layer.

[0012] The thick copper circuit board manufacturing method according to the first aspect of the present application has at least the following beneficial effects:

[0013] By using the whole thick copper layer as a conductor to electroplate nickel and gold, the need to design and remove gold leads on the copper layer in the traditional process is avoided, and mechanical damage to the circuit board (such as edge damage or local corrosion) caused by removing the leads is avoided, thereby significantly improving the yield of the circuit board.

[0014] According to some embodiments of the present application, in step 1, the whole-board electroplating process includes a whole-board electroplating pretreatment, and the steps of the whole-board electroplating pretreatment are: sequentially performing first acid washing, first water washing, second acid washing, and second water washing on the production board.

[0015] According to some embodiments of the present application, the acid washing solution used in the first acid washing and the second acid washing is a sulfuric acid solution with a concentration of 4% to 8%.

[0016] According to some embodiments of the present application, the thickness of the thick copper layer is greater than or equal to 70 microns.

[0017] According to some embodiments of the present application, in step 3, a nickel layer with a thickness of 3 to 5 microns is formed on the thick copper layer by the electroplating nickel process.

[0018] According to some embodiments of the present application, in step 3, a gold layer with a thickness of 3 to 5 microns is formed on the thick copper layer by the electroplating gold process.

[0019] According to some embodiments of the present application, in step 3, before electroplating nickel, an acidic cleaner is used to remove light grease and oxides on the surface of the thick copper layer, so that the copper surface is clean and the wettability is increased.

[0020] According to some embodiments of the present application, in step 4, the alkaline stripping solution is a solution containing sodium hydroxide, the concentration is 3 to 8 wt%, the stripping temperature is 40 to 60°C, and the stripping time is 1 to 3 minutes.

[0021] According to some embodiments of the present application, in step 5, the etching solution is a copper chloride or iron chloride solution, the etching speed is 10 to 20 microns per minute, and after etching, the line width and the verticality of the side wall are monitored in real time by optical detection equipment.

[0022] The thick copper circuit board according to the second aspect of the embodiments of the present application is obtained by the method for manufacturing a thick copper circuit board described in the above embodiments.

[0023] The thick copper circuit board according to the second aspect of the embodiments of the present application has at least the following beneficial effects:

[0024] By using the whole thick copper layer as a conductor to electroplate nickel and gold, the need to design and remove the electroplated gold leads on the copper layer in the traditional process is avoided, and mechanical damage to the circuit board (such as edge damage or local corrosion) caused by removing the leads is avoided, thereby significantly improving the yield of the circuit board.

[0025] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A flowchart of a manufacturing method of a thick copper circuit board according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described in detail below with reference to the attached drawings, in which like or similar elements are denoted by the same or similar reference numerals, and the embodiments described below are examples only, and are intended to explain the present application, and are not to be construed as limiting the present application.

[0029] In the description of the present application, it should be understood that the orientation description, such as up, down, front, back, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the present application.

[0030] In the description of the present application, several meanings are one or more, and multiple meanings are two or more, greater than, less than, more than, etc. are understood to not include the number, above, below, etc. are understood to include the number. If the first, second, etc. are described, they are only used to distinguish technical features for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.

[0031] In the description of the present application, unless otherwise explicitly limited, the words such as setting, mounting, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0032] In the related art, before electroplating nickel and electroplating gold, the copper layer needs to be designed with electroplating gold leads, and after electroplating gold, the electroplating gold leads need to be removed, which is easy to cause damage to the circuit board and reduce the yield of the circuit board.

[0033] Reference Figure 1 According to the method for manufacturing the thick copper circuit board, the whole thick copper layer is used as a conductor to perform electroplating nickel and electroplating gold, thereby avoiding the need to design and remove electroplating gold leads on the copper layer in the traditional process, avoiding mechanical damage (such as edge damage or local corrosion) to the circuit board when the leads are removed, and thereby significantly improving the yield of the circuit board.

[0034] In some embodiments of the present application, in step 1, the full-plate electroplating treatment includes full-plate electroplating pretreatment, and the steps of the full-plate electroplating pretreatment are: sequentially performing first acid washing, first water washing, second acid washing, and second water washing on the production plate, which can completely remove contaminants and oxides on the surface of the substrate, and ensure the surface cleanliness of the thick copper layer in subsequent electroplating. This improves the uniformity and adhesion of electroplating nickel and electroplating gold, reduces electroplating defects (such as holes or bubbles) caused by surface contamination, further ensures the yield, and enhances the consistency and repeatability of the method.

[0035] In some embodiments of the present application, the acid pickling solution used in the first acid pickling and the second acid pickling is a sulfuric acid solution with a concentration of 4% to 8%, which can effectively remove grease and oxides without corroding the substrate, ensuring that the surface wettability of the thick copper layer is optimized to prevent unevenness during electroplating, thereby reducing defects and improving yield, while reducing chemical agent consumption costs.

[0036] In some embodiments of the present application, the thickness of the thick copper layer is 70 microns or more, providing a highly conductive conductor basis, so that the whole thick copper layer can carry a larger current during electroplating nickel and electroplating gold, avoiding the problem of uneven electroplating or "hot spots" caused by insufficient thickness, and improving the conductive reliability and yield of the circuit board.

[0037] In some embodiments of the present application, in step 3, a nickel layer with a thickness of 3-5 μm is formed on the thick copper layer by electroplating nickel process, which can effectively prevent copper-gold interdiffusion, improve soldering reliability, avoid the risk of brittle cracking caused by over-thick nickel layer, reduce electroplated layer defects, and thus improve the yield of circuit board and long-term performance.

[0038] In some embodiments of the present application, in step 3, a gold layer with a thickness of 3-5 μm is formed on the thick copper layer by electroplating gold process, which ensures sufficient wear resistance and oxidation resistance, enhances solderability and electrical contact, and at the same time avoids the waste or "gold brittle" phenomenon caused by over-thick gold layer, reduces metal defects in the electroplating process, and improves the surface quality consistency of the circuit board.

[0039] In some embodiments of the present application, in step 3, before electroplating nickel, an acidic cleaner is used to remove light grease and oxides on the surface of the thick copper layer, so that the copper surface is clean and the wettability is increased, the surface residues (such as light grease) are completely removed, the surface wettability is improved, the bubbles or impurities embedded during electroplating nickel / gold are prevented, the defects such as non-adhesion or unevenness of the plated layer are reduced, the yield is further improved, and the electroplating process is efficient and controllable.

[0040] It can be understood that the thick copper layer has strong anti-plating dry film adhesion, and the traditional film stripping is prone to residual.

[0041] Based on this, in some embodiments of the present application, in step 4, the alkaline film stripping solution is a solution containing sodium hydroxide with a concentration of 3-8 wt%, the film stripping temperature is 40-60℃, and the film stripping time is 1-3 minutes, which can improve the dry film dissolution efficiency on the one hand, and avoid damaging the gold layer on the other hand, and ensure the solderability and electrical contact performance of the solder pad.

[0042] In some embodiments of the present application, in step 5, the etching solution is a copper chloride or iron chloride solution, the etching speed is 10-20 μm / min, and after etching, the line width and side wall perpendicularity are monitored in real time by optical detection equipment, the speed of 10-20 μm / min avoids the side wall inclination or over-etching caused by too fast etching, and the optical monitoring adjusts the deviation (such as line width and perpendicularity) in real time, which improves the size accuracy of the inner layer circuit, reduces waste, and thus directly improves the yield.

[0043] Referring to Figure 1 , the thick copper circuit board according to the second aspect of the present application is obtained by the manufacturing method of the thick copper circuit board according to the first aspect of the present application, which can improve the yield of the circuit board.

[0044] Specifically, by using the whole thick copper layer as a conductor to electroplate nickel and gold, the need to design and remove the electroplated gold leads on the copper layer in the traditional process is avoided, and the mechanical damage (such as edge damage or local corrosion) of the circuit board caused by the removal of the leads is avoided, thereby significantly improving the yield of the circuit board.

[0045] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described, but it should be understood that any combination of the technical features is within the scope of the present disclosure as long as the combination does not result in contradictions.

[0046] The above-described embodiments are described in detail in combination with the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the scope of the present application.

Claims

1. A method for manufacturing a thick copper circuit board, characterized in that, Includes the following steps: Step 1: Obtain a substrate and perform full-board electroplating on the substrate to form a thick copper layer on the substrate; Step 2: Create localized electroplating patterns on the thick copper layer by sequentially applying dry film, exposing, and developing. Step 3: Using the entire thick copper layer as a conductor, nickel and gold are electroplated sequentially at the locations of the local electroplated gold pattern; Step 4: Use an alkaline stripping solution to strip the thick copper layer; Step 5: Etch the thick copper layer with an etching solution to create inner layer circuitry on the thick copper layer.

2. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 1, the full-board electroplating process includes a full-board electroplating pretreatment, which consists of the following steps: performing a first pickling, a first water washing, a second pickling, and a second water washing on the production board in sequence.

3. The method for manufacturing a thick copper circuit board according to claim 2, characterized in that, The pickling solution used in the first and second pickling processes is a sulfuric acid solution with a concentration of 4% to 8%.

4. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, The thickness of the copper layer is 70 micrometers or more.

5. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 3, a nickel layer with a thickness of 3 to 5 μm is formed on the thick copper layer by an electroplating nickel process.

6. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 3, a gold layer with a thickness of 3 to 5 μm is formed on the thick copper layer by electroplating.

7. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 3, before electroplating nickel, an acidic cleaner is used to remove light grease and oxides from the surface of the thick copper layer, making the copper surface clean and increasing its wettability.

8. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 4, the alkaline stripping solution is a sodium hydroxide solution with a concentration of 3-8 wt%, a stripping temperature of 40-60°C, and a stripping time of 1-3 minutes.

9. The method for manufacturing a thick copper circuit board according to claim 1, characterized in that, In step 5, the etching solution is a copper chloride or ferric chloride solution, the etching rate is 10-20 μm / min, and after etching, the line width and sidewall verticality are monitored in real time by an optical inspection device.

10. A thick copper circuit board, characterized in that, The thick copper circuit board is obtained by the manufacturing method according to any one of claims 1 to 9.

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