Preparation method of water-saving and emission-reducing black shadow process circuit board

Abstract

The invention provides a preparation method of a water-saving and emission-reducing black shadow process circuit board, and the method comprises the following steps: putting a circuit substrate into a bulking groove, and carrying out the bulking treatment, sequentially putting the circuit board into a first bulky rinsing bath, a second bulky rinsing bath and a third bulky rinsing bath which are connected in series for overflow rinsing; putting the circuit board into a degumming tank for degumming treatment; and sequentially putting the circuit board into a first glue-removing washing tank, a second glue-removing washing tank and a third glue-removing washing tank which are connected in series for overflow washing, and conveying washing water in the third glue-removing washing tank into a second bulking washing tank. The three-stage series washing tanks are adopted for overflow washing, so that the utilization rate of water is increased, and the consumption of fresh washing water is reduced; the cleaning water after glue removing and washing is conveyed into the bulky water washing tank, so that waste water recycling is achieved, the waste water discharge amount in the glue removing and washing step is reduced, and the requirement for fresh cleaning water is lowered.

Description

Technical Field

[0001] The present disclosure relates to the technical field of circuit board manufacturing, and in particular to a method for preparing a circuit board using a water-saving and emission-reducing black shadow process. Background Art

[0002] The shadow process is a direct electroplating process that uses graphite as a conductive material and is parallel to chemical copper deposition. It is formaldehyde-free, heavy metal-free, and chelating agent-free, making it environmentally friendly. The shadow process has no material selectivity for preparing circuit boards, and the process is simple, mature, and stable.

[0003] In the production process of black shadow process circuit boards, after drilling, the circuit boards need to undergo the steps of swelling, degumming, neutralization and black shadow treatment. The circuit boards that have passed each step need to be sprayed and washed with water. The washing process requires a large amount of cleaning water, and the utilization efficiency of the cleaning water is low, resulting in high production water costs such as water fees and electricity fees required to produce pure water. At the same time, the large amount of wastewater generated after cleaning also increases the problem of environmental protection treatment of wastewater.

[0004] For example, the reference document CN202210550187.7 discloses a new energy vehicle, a circuit board, and a black shadow process therefor. The black shadow process for the circuit board includes some or all of the following steps: immersing the board in a bulking solution at a first predetermined temperature to bulk up the residual glue on the hole wall of the board, wherein the bulking concentration of the bulking solution is 40% to 50%, and the first predetermined temperature is greater than or equal to 75°C; immersing the bulked board in a degumming solution to remove the glue residue; placing the degummed board in an acidic solution for neutralization; and placing the neutralized board in a black shadow glue solution to form a conductive layer on the hole wall of the board. The various steps of this solution have a low utilization rate of cleaning water, and a large amount of cleaning wastewater is generated during the cleaning process. The cleaning wastewater is not reused or water conservation and emission reduction is not carried out. Summary of the Invention

[0005] The purpose of the present disclosure is to overcome the deficiencies in the prior art and provide a method for preparing a circuit board using a black shadow process with high cleaning water utilization and cleaning water reuse, which saves water and reduces emissions.

[0006] The purpose of this disclosure is achieved through the following technical solutions:

[0007] A method for preparing a water-saving and emission-reducing black shadow process circuit board comprises the following steps:

[0008] placing the circuit substrate into a bulking tank for bulking to obtain a bulked circuit board;

[0009] The bulky circuit boards are subjected to overflow water washing, and the bulky circuit boards are sequentially placed in a first bulky water washing tank, a second bulky water washing tank, and a third bulky water washing tank connected in series for spray water washing to obtain bulky water-washed circuit boards. Washing water is injected into the third bulky water washing tank and overflows into the second bulky water washing tank and the first bulky water washing tank in sequence, and then discharged through the wastewater pipe of the first bulky water washing tank;

[0010] placing the bulked water-washed circuit board into a degumming tank for degumming to obtain a degummed circuit board;

[0011] The de-glueized circuit board is subjected to overflow water washing, and the de-glueized circuit board is sequentially placed in a first de-glueizing water washing tank, a second de-glueizing water washing tank, and a third de-glueizing water washing tank connected in series for spray water washing to obtain a de-glueized water-washed circuit board, and washing water is injected into the third de-glueizing water washing tank and overflows into the second de-glueizing water washing tank and the first de-glueizing water washing tank in sequence, and then discharged through the wastewater pipe of the first de-glueizing water washing tank, and the washing water in the third de-glueizing water washing tank is transported to the second bulking water washing tank;

[0012] performing a pre-neutralization treatment and a neutralization treatment on the de-glueized water-washed circuit board to obtain a neutralized water-washed circuit board;

[0013] Performing a whole-pore treatment on the neutralized circuit board to obtain a whole-pore water-washed circuit board;

[0014] The whole hole circuit board is subjected to black shadow treatment, and the whole hole circuit board is sequentially placed in black shadow liquid and fixing liquid for treatment to obtain a black shadow process circuit board.

[0015] In one embodiment, the ratio of the injection flow rate of the washing water injected into the third bulking water washing tank to the injection flow rate of the washing water injected into the third degumming water washing tank is (1:5) to (2:5).

[0016] In one embodiment, the de-glueing water-washed circuit board is subjected to a neutralization treatment to obtain a neutralized water-washed circuit board, comprising the following steps:

[0017] placing the degumming water-washed circuit board into a pre-neutralization tank for pre-neutralization treatment to obtain a pre-neutralized circuit board;

[0018] The pre-neutralized circuit board is subjected to overflow water washing, and the pre-neutralized circuit board is sequentially placed in a first pre-neutralization water washing tank and a second pre-neutralization water washing tank connected in series for spray water washing to obtain a pre-neutralized water-washed circuit board, and washing water is injected into the second pre-neutralization water washing tank and overflows into the first pre-neutralization water washing tank, and then discharged through the wastewater pipe of the first pre-neutralization water washing tank;

[0019] placing the pre-neutralized washed circuit board into a neutralization tank for secondary neutralization treatment to obtain a neutralized circuit board;

[0020] The neutralized circuit board is overflow-washed, and the neutralized circuit board is sequentially placed in a first neutralization washing tank, a second neutralization washing tank, and a third neutralization washing tank connected in series for spray washing to obtain a neutralized washed circuit board, and washing water is injected into the third neutralization washing tank and overflows into the second neutralization washing tank and the first neutralization washing tank in sequence, and then discharged through the wastewater pipe of the first neutralization washing tank.

[0021] In one embodiment, the washing water in the first neutralization water washing tank is transported to the first pre-neutralization water washing tank.

[0022] In one embodiment, performing a whole-hole treatment on the neutralized circuit board to obtain a whole-hole water-washed circuit board includes the following steps:

[0023] placing the neutralized and washed circuit board into a hole-sizing tank for hole-sizing treatment to obtain a hole-sizing circuit board;

[0024] The whole-hole circuit board is washed with water, and the whole-hole circuit board is sequentially placed in a first whole-hole water washing tank, a second whole-hole water washing tank and a third whole-hole water washing tank connected in series for spray water washing to obtain a whole-hole water-washed circuit board, and washing water is injected into the third whole-hole water washing tank and overflows into the second whole-hole water washing tank and the first whole-hole water washing tank in sequence, and the washing water of the first whole-hole water washing tank is transported to the second neutralization water washing tank.

[0025] In one embodiment, the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the third whole-hole water washing tank is (1:5) to (2:5), and the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the second pre-water washing tank is (1:1) to (2:1).

[0026] In one embodiment, after the whole hole circuit portion is subjected to black shadow treatment, the whole hole circuit board is sequentially placed in a black shadow solution and a fixing solution for treatment to obtain a black shadow process circuit board, further comprising the following steps:

[0027] The black shadow process circuit board is dried.

[0028] In one embodiment, after the black shadow process circuit board is dried, the following steps are further included:

[0029] placing the dried black shadow process circuit board into a micro-etching tank for micro-etching to obtain a micro-etched circuit board;

[0030] The micro-etched circuit board is washed with overflow water, and the micro-etched circuit board is placed in a first micro-etching water washing tank, a second micro-etching water washing tank and a third micro-etching water washing tank connected in series in sequence for spray water washing to obtain a micro-etched water-washed circuit board, and cleaning water is injected into the third micro-etching water washing tank and overflowed to the second micro-etching water washing tank and the first micro-etching water washing tank in sequence, and then discharged through the wastewater pipe of the first micro-etching water washing tank.

[0031] In one embodiment, before washing the bulky circuit board, the circuit board is placed in a bulking agent. After bulking by the bulking agent, the following steps are further included:

[0032] The bulky circuit board is placed in a bulking recovery tank for recovery and water washing, and the bulking recovery tank is used to transport the washing liquid to the bulking tank.

[0033] In one embodiment, before washing the debonded circuit board, the debonded circuit board is placed in a debonding tank, and after debonding with a debonding agent, the following steps are further included:

[0034] The debonded circuit board is placed in a debonding recovery tank for recycling and washing, and the debonding recovery tank is used to transport the washing liquid to the debonding tank.

[0035] Compared with the prior art, the present disclosure has at least the following advantages:

[0036] The above-mentioned method for preparing circuit boards using a shadow process with water-saving and emission-reduction technology adopts three-stage series water washing tanks for spray washing in both the bulking water washing and the degumming water washing steps. The washing water is injected from the third water washing tank for bulking water washing and degumming water washing, overflows to the second and first water washing tanks in sequence, and is finally discharged through the waste water pipe of the first water washing tank. This ensures the gradient utilization of the washing water in the multiple water washing tanks, so that the washing water in the subsequent water washing tanks can countercurrently utilize the relatively clean washing water in the previous water washing tanks, thereby maximizing the utilization rate of the washing water and reducing the consumption of fresh washing water.

[0037] The cleaning water after degumming is transported to the bulking water washing tank, which realizes the reuse of the cleaning water, reduces the wastewater discharge in the degumming washing step, and also reduces the demand for fresh cleaning water in the bulking water washing process. By recycling water resources across steps, the cleaning water consumption in the preparation of circuit boards is significantly reduced, reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A flowchart of a method for preparing a circuit board using a black shadow process with water conservation and emission reduction according to an embodiment;

[0040] Figure 2 for Figure 1 Flow chart of the steps of performing pre-neutralization and neutralization treatment;

[0041] Figure 3 for Figure 1 Flow chart of the steps for hole-smoothing treatment

[0042] Figure 4 for Figure 1 The flow chart of the series connection of washing after bulking treatment and washing after degumming is shown;

[0043] Figure 5 for Figure 1 Flowchart showing water washing after pre-neutralization treatment, water washing after neutralization treatment and water washing after whole hole treatment;

[0044] Figure 6 for Figure 1 The flow chart of water washing after micro etching and water washing after secondary hole filling is shown;

[0045] Figure 7 for Figure 1 The schematic diagram of the structure of the water washing tanks in series in the method for preparing the circuit board of the water-saving and emission-reducing shadow process shown;

[0046] Figure 8 for Figure 1 The schematic diagram of the structure of the bulking water washing tank and the degumming water washing tank for conveying in the method for preparing the circuit board by the water-saving and emission-reducing black shadow process is shown. DETAILED DESCRIPTION

[0047] To facilitate understanding of the present disclosure, a more comprehensive description of the present disclosure will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present disclosure. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure.

[0048] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. The terms used herein in the specification of this disclosure are intended only to describe specific embodiments and are not intended to limit this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0050] In order to better understand the technical solutions and beneficial effects of the present disclosure, the present disclosure is further described in detail below with reference to specific embodiments:

[0051] The present application provides a method for preparing a circuit board using a water-saving and emission-reducing black shadow process. The method comprises the following steps: placing a circuit substrate into a puffing tank for puffing treatment to obtain a puffed circuit board; performing overflow water washing on the puffed circuit board, placing the puffed circuit board into a first puffing water washing tank, a second puffing water washing tank and a third puffing water washing tank connected in series in sequence for spray water washing to obtain a puffed water-washed circuit board, injecting washing water into the third puffing water washing tank and overflowing into the second puffing water washing tank and the first puffing water washing tank in sequence, and then discharging the water through the wastewater pipe of the first puffing water washing tank; placing the puffed water-washed circuit board into a degumming tank for degumming treatment to obtain a degummed circuit board; performing overflow water washing on the degummed circuit board, and placing the degummed circuit board into a series of first puffing water washing tanks in sequence. The circuit board is placed in a first degumming water washing tank, a second degumming water washing tank and a third degumming water washing tank connected in series for spray water washing to obtain a degumming water-washed circuit board, and washing water is injected into the third degumming water washing tank and overflows to the second degumming water washing tank and the first degumming water washing tank in sequence, and then discharged through the waste water pipe of the first degumming water washing tank, and the washing water in the third degumming water washing tank is transported to the second bulking water washing tank; the degumming water-washed circuit board is pre-neutralized and neutralized to obtain a neutralized water-washed circuit board; the neutralized circuit board is subjected to a whole-hole treatment to obtain a whole-hole water-washed circuit board; the whole-hole circuit board is subjected to a black shadow treatment, and the whole-hole circuit board is sequentially placed in a black shadow liquid and a fixing liquid for treatment to obtain a black shadow process circuit board.

[0052] See also Figures 1 to 4 and Figure 7 and Figure 8As shown, in one embodiment, the present application provides a method for preparing a circuit board using a water-saving and emission-reducing black shadow process, comprising the following steps:

[0053] S101 places the circuit substrate in a bulking tank for bulking to obtain a bulked circuit board. In this embodiment, the bulking agent is sodium hydroxide and an alcohol ether bulking solution. The bulking agent in the bulking tank bulks the circuit substrate, causing the resin in the hole walls of the circuit substrate to expand and soften the glue residue.

[0054] S103 performs overflow water washing on the puffed circuit board. The puffed circuit board is sequentially placed in a first, second, and third puffed water washing tank connected in series for spray water washing to obtain a puffed water-washed circuit board. Washing water is injected into the third puffed water washing tank, and the overflow is sequentially transferred to the second and first puffed water washing tanks, and then discharged through the wastewater pipe of the first puffed water washing tank. In this embodiment, by washing the puffed circuit board multiple times, the leavening agent residue and impurities on the circuit board surface can be gradually removed, thereby improving the cleaning effect of the puffed water-washed circuit board. The overflow water washing design gradually improves the water quality from the first to the third puffed water washing tank, reducing the risk of cross-contamination and improving the utilization efficiency of the washing water. Washing water is injected into the third puffed water washing tank to ensure that the water in the third puffed water washing tank is clean, thereby achieving a better final cleaning effect on the puffed circuit board.

[0055] In step S105, the bulky water-washed circuit board is placed in a degumming tank for degumming to obtain a degummed circuit board. In this embodiment, the degumming treatment is performed on the bulky water-washed circuit board using a degumming solution in the degumming tank. The degumming agent is potassium permanganate solution, and the potassium permanganate is used to oxidize and remove glue residue and resin residue on the bulky water-washed circuit board.

[0056] S107 performs overflow water washing on the de-glueing circuit board. The de-glueing circuit board is sequentially placed in a first de-glueing water washing tank, a second de-glueing water washing tank, and a third de-glueing water washing tank connected in series for spray water washing to obtain a de-glueing water-washed circuit board. Washing water is injected into the third de-glueing water washing tank and overflows into the second de-glueing water washing tank and the first de-glueing water washing tank in sequence. The water is then discharged through the wastewater pipe of the first de-glueing water washing tank and the washing water in the third de-glueing water washing tank is transported to the second bulking water washing tank. In this embodiment, by performing multiple washing on the de-glueing circuit board, the cleaning effect of the de-glueing circuit board is improved; the washing water overflows into the second de-glueing water washing tank and the first de-glueing water washing tank in sequence, reducing the risk of cross contamination and improving the utilization efficiency of the washing water.

[0057] It can be understood that when the cleaning water containing potassium permanganate in the third degumming water washing tank is transported to the second bulking water washing tank, the cleaning water used to clean the degumming circuit board is reversely recycled to clean the bulking water-washed circuit board, and the overflow design of the cleaning water for overflow water washing of the bulking circuit board avoids the potassium permanganate and impurities in the cleaning water used to clean the degumming circuit board from contaminating the third bulking water washing tank, ensures the cleaning effect of the third bulking water washing tank on the bulking water-washed circuit board, increases the flow rate of the cleaning water in the second bulking water washing tank, saves the amount of cleaning water, and reduces the discharge volume of the waste water pipe of the first bulking water washing tank.

[0058] S109 performs a pre-neutralization and a neutralization treatment on the de-glue-washed circuit board to obtain a neutralized water-washed circuit board. In this embodiment, the de-glue-washed circuit board is pre-neutralized with a pre-neutralizer and then subjected to a secondary neutralization with a neutralizer. The pre-neutralizer and the neutralizer are reducing agent solutions such as hydrogen peroxide or oxalic acid. The pre-neutralizer and the neutralizer are used to neutralize residual potassium permanganate. The secondary neutralization ensures that the potassium permanganate in the neutralized circuit board is completely removed.

[0059] S111 performs a hole-splitting process on the neutralized circuit board to obtain a hole-splitting water-washed circuit board. In this embodiment, the hole-splitting machine is used to clean the hole walls of the neutralized circuit board and modulate the charge on the hole wall surface to improve adhesion, thereby facilitating the subsequent deposition of the conductive layer.

[0060] After the entire hole circuit portion is subjected to black shadow treatment, the entire hole circuit board is sequentially placed in a black shadow solution and a fixing solution for treatment to obtain a black shadow process circuit board. In this embodiment, the black shadow solution containing nanographite or colloidal palladium is deposited on the hole wall through chemical adsorption to form a conductive layer. The fixing solution containing an acidic solution is then used to remove loose particles and stabilize the conductive layer.

[0061] The above-mentioned method for preparing circuit boards using the black shadow process of saving water and reducing emissions adopts three-stage series water washing tanks for spray water washing in both the bulking water washing and degumming water washing steps. The washing water is injected from the third water washing tank for bulking water washing and degumming water washing and overflows to the second and first water washing tanks in sequence, and is finally discharged through the waste water pipe of the first water washing tank, ensuring the gradient utilization of the washing water in multiple water washing tanks, so that the washing water in the subsequent water washing tanks can countercurrently utilize the relatively clean washing water in the previous water washing tank, thereby maximizing the utilization rate of the washing water and reducing the consumption of fresh washing water; the washing water after degumming water washing is transported to the bulking water washing tank, realizing the reuse of the washing water, reducing the wastewater discharge in the degumming water washing step, and reducing the demand for fresh washing water in the bulking water washing process. By recycling water resources across steps, the washing water consumption in the preparation of circuit boards is significantly reduced, reducing production costs.

[0062] In one embodiment, the ratio of the injection flow rate of the washing water injected into the third bulking water washing tank to the injection flow rate of the washing water injected into the third degumming water washing tank is (1:5) to (2:5). In this embodiment, the washing water of the second bulking water washing tank includes the washing water overflowed from the third degumming water washing tank and the washing water recycled from the third degumming water washing tank, so that the washing flow rate of the second bulking water washing tank is increased, the flow rate of the washing water that needs to overflow from the third degumming water washing tank into the second bulking water washing tank is reduced, and the flow rate of the washing water required to be injected into the third degumming water washing tank is reduced; by controlling the injection flow rate of the washing water injected into the third bulking water washing tank to the injection flow rate of the washing water injected into the third degumming water washing tank to be (1:5) to (2:5), the cleaning effect of the third degumming water washing tank on the degummed circuit board is ensured, and the flow rate of the washing water injected into the third degumming water washing tank is saved.

[0063] like Figure 2 and Figure 5 As shown, in one embodiment, the de-glueing water-washed circuit board is pre-neutralized and neutralized to obtain a neutralized water-washed circuit board, comprising the following steps:

[0064] S1051: placing the debonding water-washed circuit board into a pre-neutralization tank for pre-neutralization treatment to obtain a pre-neutralized circuit board;

[0065] S1053: The pre-neutralized circuit board is subjected to overflow water washing. The pre-neutralized circuit board is sequentially placed in a first pre-neutralization water washing tank and a second pre-neutralization water washing tank connected in series for spray water washing to obtain a pre-neutralized water-washed circuit board. Washing water is injected into the second pre-neutralization water washing tank and overflows into the first pre-neutralization water washing tank, and then discharged through the wastewater pipe of the first pre-neutralization water washing tank.

[0066] S1055: placing the pre-neutralized washed circuit board into a neutralization tank for secondary neutralization treatment to obtain a neutralized circuit board;

[0067] S1057 performs overflow water washing on the neutralized circuit board, and sequentially places the neutralized circuit board into the first neutralization water washing tank, the second neutralization water washing tank and the third neutralization water washing tank connected in series for spray water washing to obtain a neutralized water-washed circuit board, injects washing water into the third neutralization water washing tank and overflows into the second neutralization water washing tank and the first neutralization water washing tank in sequence, and then is discharged through the wastewater pipe of the first neutralization water washing tank.

[0068] In this embodiment, the pre-neutralization circuit board is overflow washed by the first pre-neutralization water washing tank and the second pre-neutralization water washing tank connected in series, and the neutralization circuit board is overflow washed by the first neutralization water washing tank, the second neutralization water washing tank and the third neutralization water washing tank connected in series, thereby improving the utilization efficiency of the washing water; it can be understood that the residual potassium permanganate on the circuit board is neutralized in turn by the acidic pre-neutralizer in the pre-neutralization tank and the acidic neutralizer in the neutralization tank, and the acidic pre-neutralizer remaining on the pre-neutralization water-washed circuit board has little effect on the neutralizer in the neutralization tank, and the pre-neutralization circuit board is washed with two-stage water washing tanks in series, thereby saving the water washing process and improving the water washing efficiency; the residual acidic neutralizer on the neutralization circuit board has a greater effect on the weak alkaline pore-leveling agent in the pore-leveling treatment, and the neutralization circuit board needs to be washed with three-stage water washing tanks in series to ensure the water washing effect of the neutralization circuit board.

[0069] In one embodiment, the wash water in the first neutralization water washing tank is transferred to the first pre-neutralization water washing tank. In this embodiment, by reusing the wash water in the first neutralization water washing tank in the first pre-neutralization water washing tank for pre-neutralization, the water flow rate of the first pre-neutralization water washing tank is increased, and the water flow rate of the second pre-neutralization water washing tank is reduced, thereby reducing the amount of wash water injected into the pre-neutralization treatment and saving the discharge amount of the pre-neutralization treatment.

[0070] like Figure 3 As shown, in one embodiment, the neutralized circuit board is subjected to a whole-hole treatment to obtain a whole-hole water-washed circuit board, comprising the following steps:

[0071] S1071: placing the neutralized and washed circuit board into a hole-sizing tank for hole-sizing treatment to obtain a hole-sizing circuit board;

[0072] S1073 washes the whole-hole circuit board, and sequentially places the whole-hole circuit board into the first whole-hole water washing tank, the second whole-hole water washing tank, and the third whole-hole water washing tank connected in series for spray washing to obtain a whole-hole water-washed circuit board, injects washing water into the third whole-hole water washing tank and overflows into the second whole-hole water washing tank and the first whole-hole water washing tank in sequence, and transports the washing water of the first whole-hole water washing tank to the second neutralization water washing tank. In this embodiment, by connecting the first whole-hole water washing tank, the second neutralization water washing tank, the first neutralization water washing tank, and the first pre-neutralization water washing tank in series, the washing water of the first whole-hole water washing tank is transported to the second neutralization water washing tank for reuse, the washing water of the second neutralization water washing tank overflows into the first neutralization water washing tank, and then the washing water in the first neutralization water washing tank is transported to the first pre-neutralization water washing tank for reuse, and the recycled water of the first whole-hole water washing tank is transported to the second neutralization water washing tank, and its alkalinity can neutralize the acidic wastewater in the second neutralization tank, thereby reducing the second The neutralization tank has a demand for fresh cleaning water. The cleaning water flow in the first pre-neutralization water washing tank and the second neutralization water washing tank is increased, which improves the washing effect of the pre-neutralization water-washed circuit boards and the neutralization water-washed circuit boards, so that the cleaning water injection flow in the second pre-neutralization water washing tank for pre-neutralization treatment and the third neutralization water washing tank for neutralization treatment is reduced simultaneously. The waste water after cleaning is discharged through the drain pipe of the first pre-neutralization water washing tank, so that the large amount of waste water discharged after reuse in the pre-neutralization treatment, neutralization treatment and whole-hole treatment is reduced.

[0073] In one embodiment, the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the third whole-hole water washing tank is (1:5) to (2:5), and the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the second pre-water washing tank is (1:1) to (2:1). In this embodiment, the third whole-hole water washing tank needs to inject cleaning water with a larger injection flow rate, so that the cleaning water flow rate overflowing into the second whole-hole water washing tank and the first whole-hole water washing tank is larger, so as to ensure the cleaning effect of the second whole-hole water washing tank and the first whole-hole water washing tank on the whole-hole circuit board; the cleaning water of the second neutralization water washing tank includes the cleaning water overflowed from the third neutralization water washing tank and the cleaning water recycled from the first whole-hole water washing tank, reducing the cleaning water injection amount of the third neutralization water washing tank; the cleaning water of the first pre-neutralization water washing tank includes the cleaning water overflowed from the second pre-neutralization water washing tank and the cleaning water recycled from the first neutralization water washing tank, and the cleaning water overflowed from the second neutralization water washing tank into the first neutralization water The flow rate of the washing water recycled in the washing tank is relatively large, and the amount of washing water injected into the second reserved neutralization water washing tank can be further reduced to half of the injection flow rate of the washing water injected into the third neutralization water washing tank; by controlling the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the third whole-hole water washing tank to be (1:5) to (2:5), the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the second pre-water washing tank is (1:1) to (2:1), so that the utilization rate of the washing water for pre-neutralization treatment, neutralization treatment and whole-hole treatment is improved, and a good cleaning effect on the circuit board is maintained.

[0074] In one embodiment, after the whole hole circuit portion is subjected to black shadow treatment, the whole hole circuit board is sequentially placed in a black shadow solution and a fixing solution for treatment to obtain a black shadow process circuit board, further comprising the following steps:

[0075] In this embodiment, after obtaining the black shadow process circuit board, the residual moisture on the surface of the circuit board and in the holes can be removed by drying, and the conductive layer formed on the hole wall of the black shadow process circuit board can be solidified.

[0076] In one embodiment, after the black shadow process circuit board is dried, the following steps are further included:

[0077] placing the dried black shadow process circuit board into a micro-etching tank for pre-micro-etching to obtain a pre-micro-etched circuit board;

[0078] The pre-etched circuit board is subjected to overflow water washing. The pre-etched circuit board is sequentially placed in a first pre-etched water washing tank, a second pre-etched water washing tank, and a third pre-etched water washing tank connected in series for spray water washing to obtain a pre-etched water-washed circuit board. Rinse water is injected into the third pre-etched water washing tank, and the overflow is sequentially transferred to the second pre-etched water washing tank and the first pre-etched water washing tank, and then discharged through the waste water pipe of the first pre-etched water washing tank. In this embodiment, the circuit board is micro-etched with an etching liquid to remove carbon residue on the board surface during the black shadow process. The first pre-etched water washing tank, the second pre-etched water washing tank, and the third pre-etched water washing tank are connected in series for spray water washing. Rinse water is injected into the third pre-etched water washing tank, and the overflow is sequentially transferred to the second pre-etched water washing tank and the first pre-etched water washing tank. This improves the cleaning effect of the pre-etched circuit board and increases the utilization rate of the washing water in the overflow washing.

[0079] It is understandable that when the circuit board is a multi-layer circuit board, the thickness of the multi-layer circuit board is thicker, the ratio of hole depth to hole diameter increases, and the conductive layer base formed on the hole wall of the circuit board through a single black shadow process is thin and difficult to completely cover the hole wall, resulting in poor conductive reliability of copper plating on the circuit board. The multi-layer circuit board needs to be subjected to a secondary black shadow treatment to fill the defects of the conductive layer in the hole wall of the multi-layer circuit board and increase the thickness.

[0080] like Figure 6 As shown, further, in one embodiment, performing secondary black shadow processing on the black shadow process circuit board includes the following steps:

[0081] The pre-micro-etched and water-washed circuit board is placed in a secondary hole-forming tank for secondary hole-forming to obtain a secondary hole-forming circuit board;

[0082] The micro-etched and washed circuit board after the secondary hole-straightening is subjected to overflow water washing, washing water is injected into the sixth hole-straightening water washing tank and overflows to the fifth hole-straightening water washing tank and the fourth hole-straightening water washing tank in sequence, the washing water of the fourth hole-straightening water washing tank is transported to the second micro-etched water washing tank, and the micro-etched and washed circuit board is sequentially placed in the fourth hole-straightening water washing tank, the fifth hole-straightening water washing tank and the sixth hole-straightening water washing tank connected in series for spray water washing to obtain a secondary hole-straightening water-washed circuit board;

[0083] Performing shadow treatment on the secondary hole-washed circuit board in sequence, and sequentially placing the secondary hole-washed circuit board into a shadow solution and a fixer solution for treatment to obtain a secondary shadow circuit board;

[0084] Drying the secondary black shadow circuit board, and then performing post-micro-etching on the secondary black shadow circuit board after drying;

[0085] The micro-etched circuit board is dried to obtain a multi-layer circuit board.

[0086] In this embodiment, the secondary black shadow treatment uses a black shadow liquid containing nanographite or colloidal palladium to deposit a conductive layer again, fill micro-etching defects, and improve the coverage and quality of the conductive layer in the hole wall, so that the conductive reliability of the copper plating of the circuit board is better; the first pre-micro-etching water washing tank, the second pre-micro-etching water washing tank and the third pre-micro-etching water washing tank are connected in series, and the flow direction of the cleaning water is opposite to the movement direction of the micro-etching water-washed circuit board, so that the cleaning effect of the micro-etching water-washed circuit board is better and the utilization rate of the cleaning water is higher; by reversing the cleaning water used to clean the secondary whole-hole circuit board to the cleaning water of the second pre-micro-etching water washing tank, the flow rate of the cleaning water of the second pre-micro-etching water washing tank is increased, and the flow rate of the injected cleaning water of the third pre-micro-etching water washing tank is reduced, thereby reusing the cleaning water of the fourth whole-hole water washing tank and discharging it through the waste water pipe of the first pre-micro-etching water washing tank, reducing the amount of wastewater discharged from the pre-micro-etching treatment and the secondary whole-hole.

[0087] Furthermore, the ratio of the injection flow rate of the cleaning water into the third pre-micro-etching water washing tank to the injection flow rate of the cleaning water into the sixth full-hole water washing tank is (1:5) to (2:5). In this embodiment, by controlling the ratio of the injection flow rate of the cleaning water into the sixth full-hole water washing tank to the injection flow rate of the cleaning water into the third pre-micro-etching water washing tank to (1:5) to (2:5), the cleaning effect of the pre-micro-etching circuit board is ensured when the injection flow rate of the cleaning water into the third pre-micro-etching water washing tank is reduced.

[0088] In one embodiment, before washing the bulky circuit board, the circuit board is placed in a bulking agent. After bulking by the bulking agent, the following steps are further included:

[0089] The bulked circuit boards are placed in a bulking recovery tank for recovery and washing. The bulking recovery tank is used to transfer the washing liquid to the bulking tank. In this embodiment, the bulked circuit boards require heating during bulking in the bulking tank. By transferring the washing liquid from the bulking recovery tank to the bulking tank, the water in the bulking tank can be replenished and the leavening agent remaining in the washing liquid can be reused.

[0090] In one embodiment, before washing the debonded circuit board, the expanded water-washed circuit board is placed in a debonding tank, and after debonding with a debonding agent, the following steps are further included:

[0091] The debonded circuit board is placed in a debonding recovery tank for recycling and washing. The debonding recovery tank is used to transfer the washing liquid to the debonding tank. In this embodiment, when the debonded circuit board is placed in the debonding tank for debonding, the temperature of the debonding tank is relatively high, and a large amount of water evaporates. By transferring the washing liquid from the debonding recovery tank to the debonding tank, the water in the debonding tank can be replenished and the potassium permanganate debonding agent remaining in the washing liquid can be reused.

[0092] Compared with the prior art, the present disclosure has at least the following advantages:

[0093] The above-mentioned method for preparing circuit boards using a shadow process with water-saving and emission-reduction technology adopts three-stage series water washing tanks for spray washing in both the bulking water washing and the degumming water washing steps. The washing water is injected from the third water washing tank for bulking water washing and degumming water washing, overflows to the second and first water washing tanks in sequence, and is finally discharged through the waste water pipe of the first water washing tank. This ensures the gradient utilization of the washing water in the multiple water washing tanks, so that the washing water in the subsequent water washing tanks can countercurrently utilize the relatively clean washing water in the previous water washing tanks, thereby maximizing the utilization rate of the washing water and reducing the consumption of fresh washing water.

[0094] The cleaning water after degumming is transported to the bulking water washing tank, which realizes the reuse of the cleaning water, reduces the wastewater discharge in the degumming washing step, and also reduces the demand for fresh cleaning water in the bulking water washing process. By recycling water resources across steps, the cleaning water consumption in the preparation of circuit boards is significantly reduced, reducing production costs.

[0095] The above-described embodiments merely represent several implementation methods of the present disclosure. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the scope of the present disclosure, all of which fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the disclosed patent shall be determined by the appended claims.

Claims

1. A method for preparing a circuit board using a water-saving and emission-reducing black shadow process, characterized in that: The steps include: placing the circuit substrate into a bulking tank for bulking to obtain a bulked circuit board; The bulky circuit boards are subjected to overflow water washing, and the bulky circuit boards are sequentially placed in a first bulky water washing tank, a second bulky water washing tank, and a third bulky water washing tank connected in series for spray water washing to obtain bulky water-washed circuit boards. Washing water is injected into the third bulky water washing tank and overflows into the second bulky water washing tank and the first bulky water washing tank in sequence, and then discharged through the wastewater pipe of the first bulky water washing tank; placing the bulked water-washed circuit board into a degumming tank for degumming to obtain a degummed circuit board; The de-glueized circuit board is subjected to overflow water washing, and the de-glueized circuit board is sequentially placed in a first de-glueizing water washing tank, a second de-glueizing water washing tank, and a third de-glueizing water washing tank connected in series for spray water washing to obtain a de-glueized water-washed circuit board, and washing water is injected into the third de-glueizing water washing tank and overflows into the second de-glueizing water washing tank and the first de-glueizing water washing tank in sequence, and then discharged through the wastewater pipe of the first de-glueizing water washing tank, and the washing water in the third de-glueizing water washing tank is transported to the second bulking water washing tank; performing a pre-neutralization treatment and a neutralization treatment on the de-glueized water-washed circuit board to obtain a neutralized water-washed circuit board; Performing a whole-pore treatment on the neutralized circuit board to obtain a whole-pore water-washed circuit board; The whole hole circuit board is subjected to black shadow treatment, and the whole hole circuit board is sequentially placed in black shadow liquid and fixing liquid for treatment to obtain a black shadow process circuit board.

2. The method for preparing a water-saving and emission-reducing black shadow process circuit board according to claim 1, characterized in that: The ratio of the injection flow rate of the washing water injected into the third bulking water washing tank to the injection flow rate of the washing water injected into the third degumming water washing tank is (1:5) to (2:5).

3. The method for preparing a water-saving and emission-reducing black shadow process circuit board according to claim 1, characterized in that: The de-glueing water-washed circuit board is subjected to a neutralization treatment to obtain a neutralized water-washed circuit board, comprising the following steps: placing the degumming water-washed circuit board into a pre-neutralization tank for pre-neutralization treatment to obtain a pre-neutralized circuit board; The pre-neutralized circuit board is subjected to overflow water washing, and the pre-neutralized circuit board is sequentially placed in a first pre-neutralization water washing tank and a second pre-neutralization water washing tank connected in series for spray water washing to obtain a pre-neutralized water-washed circuit board, and washing water is injected into the second pre-neutralization water washing tank and overflows into the first pre-neutralization water washing tank, and then discharged through the wastewater pipe of the first pre-neutralization water washing tank; placing the pre-neutralized washed circuit board into a neutralization tank for secondary neutralization treatment to obtain a neutralized circuit board; The neutralized circuit board is overflow-washed, and the neutralized circuit board is sequentially placed in a first neutralization washing tank, a second neutralization washing tank, and a third neutralization washing tank connected in series for spray washing to obtain a neutralized washed circuit board, and washing water is injected into the third neutralization washing tank and overflows into the second neutralization washing tank and the first neutralization washing tank in sequence, and then discharged through the wastewater pipe of the first neutralization washing tank.

4. The method for preparing a water-saving and emission-reducing black shadow process circuit board according to claim 3, characterized in that: The washing water in the first neutralization water washing tank is transported to the first pre-neutralization water washing tank.

5. The method for preparing a circuit board using a water-saving and emission-reducing black shadow process according to claim 4, characterized in that: Performing a whole-hole treatment on the neutralized circuit board to obtain a whole-hole water-washed circuit board comprises the following steps: placing the neutralized and washed circuit board into a hole-sizing tank for hole-sizing treatment to obtain a hole-sizing circuit board; The whole-hole circuit board is washed with water, and the whole-hole circuit board is sequentially placed in a first whole-hole water washing tank, a second whole-hole water washing tank and a third whole-hole water washing tank connected in series for spray water washing to obtain a whole-hole water-washed circuit board, and washing water is injected into the third whole-hole water washing tank and overflows into the second whole-hole water washing tank and the first whole-hole water washing tank in sequence, and the washing water of the first whole-hole water washing tank is transported to the second neutralization water washing tank.

6. The method for preparing a water-saving and emission-reducing black shadow process circuit board according to claim 5, characterized in that: The ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the third full-hole water washing tank is (1:5) to (2:5), and the ratio of the injection flow rate of the washing water injected into the third neutralization water washing tank to the injection flow rate of the washing water injected into the second pre-water washing tank is (1:1) to (2:1).

7. The method for preparing a circuit board using a black shadow process with water saving and emission reduction according to claim 1, characterized in that: After the whole hole circuit portion is subjected to black shadow treatment, the whole hole circuit board is sequentially placed in a black shadow solution and a fixing solution for treatment to obtain a black shadow process circuit board, which further includes the following steps: The black shadow process circuit board is dried.

8. The method for preparing a circuit board using a water-saving and emission-reducing black shadow process according to claim 7, characterized in that: After the black shadow process circuit board is dried, the following steps are also included: placing the dried black shadow process circuit board into a micro-etching tank for micro-etching to obtain a micro-etched circuit board; The micro-etched circuit board is washed with overflow water, and the micro-etched circuit board is placed in a first micro-etching water washing tank, a second micro-etching water washing tank and a third micro-etching water washing tank connected in series in sequence for spray water washing to obtain a micro-etched water-washed circuit board, and cleaning water is injected into the third micro-etching water washing tank and overflowed to the second micro-etching water washing tank and the first micro-etching water washing tank in sequence, and then discharged through the wastewater pipe of the first micro-etching water washing tank.

9. The method for preparing a circuit board using a water-saving and emission-reducing black shadow process according to claim 1, characterized in that: Before washing the bulky circuit board, the circuit board is placed in a bulking agent. After bulking by the bulking agent, the following steps are further included: The bulky circuit board is placed in a bulking recovery tank for recovery and water washing, and the bulking recovery tank is used to transport the washing liquid to the bulking tank.

10. The method for preparing a water-saving and emission-reducing black shadow process circuit board according to claim 1, characterized in that: Before washing the debonded circuit board, the debonded circuit board is placed in a debonding tank. After debonding with a debonding agent, the method further includes the following steps: The debonded circuit board is placed in a debonding recovery tank for recycling and washing, and the debonding recovery tank is used to transport the washing liquid to the debonding tank.

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