阅读说明：本技术 一种高厚径比Mi ni LED印制电路板的加工方法 (Processing method of Mini LED printed circuit board with high thickness-to-diameter ratio ) 是由 潘康超 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种高厚径比Mi ni LED印制电路板的加工方法,包括以下步骤：钻孔－沉铜－电镀-沉铜－蚀刻－阻焊－压板(温度150度、压力6KG)－测试－终检－出货。本发明所述的一种高厚径比Mi ni LED印制电路板的加工方法,在原流程上增加第二次沉铜,第一次沉铜后进行电镀以巩固导通孔内铜层,第二次沉铜主要是修复第一沉铜出现的漏沉漏镀问题,由于导通孔孔径小沉铜药水不易于渗透出现漏沉铜,增加一次沉铜则增加药水流动错位机会,完全杜绝漏沉问题,再增加测试前压板利用高温高压物理原理(热胀冷缩),对由沉铜引起铜层偏簿,是断非断等问题进行老化,导致不良问题断裂,在测试时拦截,避免不良流出,增加压板则使客户投诉率由0.6％变为0。(The invention discloses a method for processing a Mini LED printed circuit board with a high thickness-to-diameter ratio, which comprises the following steps: drilling, copper deposition, electroplating, copper deposition, etching, solder resistance, pressing plate (temperature of 150 ℃ and pressure of 6KG), testing, final inspection and shipment. The invention relates to a method for processing a Mi ni LED printed circuit board with a high thickness-to-diameter ratio, which is characterized in that secondary copper deposition is added on the original flow, electroplating is carried out after the primary copper deposition to consolidate a copper layer in a through hole, the secondary copper deposition mainly repairs the problem of leakage, sinking and leakage plating caused by the primary copper deposition, the problem of leakage and sinking caused by the fact that a copper deposition liquid medicine cannot easily permeate the through hole due to small aperture of the through hole, the probability of liquid medicine flowing and dislocation is increased due to the fact that the primary copper deposition is increased, the problem of leakage and sinking is completely solved, a pressing plate before testing is added, the problems that the copper layer is thin due to copper deposition, the copper layer is broken and not broken are aged due to the fact that the copper layer is broken and not broken are aged due to the high-temperature high-pressure physical principle (thermal expansion and cold contraction), poor problem breakage is caused by intercepting during testing, poor outflow is avoided, and the fact that the complaint rate of a customer is changed from 0.6% to 0 due to the increase of the pressing plate.)

1. A processing method of a Mini LED printed circuit board with a high thickness-diameter ratio is characterized by comprising the following steps:

step one, drilling: firstly, punching a plurality of pin holes in the short edge position of the copper-coated substrate by using a pin punching machine, then fixing the combined plate with the punched pin holes on a workbench of a numerical control drilling machine, setting the main shaft rotating speed and the cutter dropping speed of the drilling machine, drilling the combined plate, taking the combined plate off the workbench of the numerical control drilling machine after the combined plate is drilled, then withdrawing the pins on the combined plate by using a pin withdrawing machine to obtain the substrate after the holes are drilled, then treating burrs and burrs on the surface of the substrate by using abrasive paper, and then checking the holes drilled on the substrate by using a hole checking machine;

step two, depositing copper for the first time: removing oil stain, fingerprints, oxides and dust in holes of the plate surface, enabling the hole walls to be adjusted from negative charges to positive charges, facilitating the adsorption of colloidal palladium in the subsequent process, removing the oxides on the plate surface, coarsening the plate surface, ensuring that a subsequent copper deposition layer has good binding force with base copper of a substrate, and being capable of well adsorbing the colloidal palladium, enabling the positively charged hole walls to effectively adsorb enough colloidal palladium particles with negative charges after the pretreatment alkaline degreasing polarity adjustment, so as to ensure the average, continuity and compactness of the subsequent copper deposition, removing stannous ions coated outside the colloidal palladium particles, exposing palladium cores in the colloidal particles, directly and effectively catalyzing and starting the chemical copper deposition reaction, inducing the chemical copper deposition autocatalytic reaction by the activation of the palladium cores, and enabling the newly generated chemical copper and reaction byproduct hydrogen to be used as a reaction catalyst for catalytic reaction, so as to enable the copper deposition reaction to be continuously carried out, after the treatment of the step, a layer of chemical copper can be deposited on the plate surface or the hole wall;

step three, electroplating: the electroplating tank body is divided into two electroplating tanks by adopting a printed circuit board plating part needing through-hole copper electroplating as a partition board, wherein the surface of electroplating solution in one electroplating tank is higher than the surface of electroplating solution in the other electroplating tank, a pressure difference is formed between the two electroplating tanks, so that the electroplating solution can flow from a high-position electroplating solution tank to a low-position electroplating solution tank through the through-hole, the electroplating solution in the hole is continuously updated, the electroplating solution in the low-position electroplating tank is pumped back to the electroplating tank with the high-position solution tank by a water suction pump to maintain the pressure difference, the through-hole copper electroplating adopts direct current electroplating, the cathode does not need to swing in the electroplating process, and the electroplating solution does not need to be stirred by inflation;

step four, copper precipitation for the second time: adopting the copper deposition method in the second step;

step five, etching: in alkaline environment solution, copper ions are very easy to form copper hydroxide precipitate, enough ammonia water is needed to be added to generate a copper ammonia complex ion group, the occurrence of the precipitate can be inhibited, simultaneously, the original large amount of copper and the continuously dissolved copper form very stable copper ammonia complex ions in the solution, the divalent copper ammonia complex ions can be used as an oxidizing agent to oxidize and dissolve zero-valent metal copper, but cuprous ions appear in the oxidation-reduction reaction process;

step six, solder resist: respectively printing two surfaces of a printed circuit board by adopting solder resist ink through a 68T polyester screen printing plate, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in an oven, cooling to room temperature after baking is finished, printing two surfaces of the cooled printed circuit board by adopting the solder resist ink through the polyester screen printing plate again, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in the oven, cooling to room temperature after baking is finished, and sequentially carrying out solder resist film alignment, exposure and development on the cooled printed circuit board;

step seven, pressing a plate: pressing the plate under the physical principle of high temperature and high pressure with the temperature of 150 ℃ and the pressure of 6kg, and detecting the existing problems;

and step eight, testing, final inspection and shipment.

2. The method for processing the Mini LED printed circuit board with the high thickness-to-diameter ratio as claimed in claim 1, wherein the method comprises the following steps: and sixthly, baking at the temperature of 75 +/-3 ℃ for 15-20 minutes.

Technical Field

The invention relates to the technical field of circuit board manufacturing, in particular to a method for processing a Mi ni LED printed circuit board with a high thickness-diameter ratio.

Background

The Mi ni LED circuit board is an important module of a display screen, and has the most remarkable characteristics that the hole diameter of a via hole is small, the wiring is dense, and the hole diameter is generally 0.15-0.2 mm. At present, the manufacturing process of the Mi ni LED circuit board comprises the following steps: drilling, copper precipitation, circuit, electroplating, etching, solder resistance, character routing, testing, final inspection and shipment. This production process flow is prone to via cracking or copper-free non-conduction problems. Mainly, the small hole diameter of the via hole is not easy to permeate the copper deposition liquid medicine, and the bad proportion is 4-6%. Therefore, a method for processing the Mini LED printed circuit board with the high thickness-to-diameter ratio is provided.

Disclosure of Invention

The invention mainly aims to provide a method for processing a Mi ni LED printed circuit board with a high thickness-to-diameter ratio, which can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention adopts the technical scheme that:

a processing method of a Mini LED printed circuit board with a high thickness-to-diameter ratio comprises the following steps:

step one, drilling: firstly, punching a plurality of pin holes in the short edge position of the copper-coated substrate by using a pin punching machine, then fixing the combined plate with the punched pin holes on a workbench of a numerical control drilling machine, setting the main shaft rotating speed and the cutter dropping speed of the drilling machine, drilling the combined plate, taking the combined plate off the workbench of the numerical control drilling machine after the combined plate is drilled, then withdrawing the pins on the combined plate by using a pin withdrawing machine to obtain the substrate after the holes are drilled, then treating burrs and burrs on the surface of the substrate by using abrasive paper, and then checking the holes drilled on the substrate by using a hole checking machine;

step two, depositing copper for the first time: removing oil stain, fingerprints, oxides and dust in holes of the plate surface, enabling the hole walls to be adjusted from negative charges to positive charges, facilitating the adsorption of colloidal palladium in the subsequent process, removing the oxides on the plate surface, coarsening the plate surface, ensuring that a subsequent copper deposition layer has good binding force with base copper of a substrate, and being capable of well adsorbing the colloidal palladium, enabling the positively charged hole walls to effectively adsorb enough colloidal palladium particles with negative charges after the pretreatment alkaline degreasing polarity adjustment, so as to ensure the average, continuity and compactness of the subsequent copper deposition, removing stannous ions coated outside the colloidal palladium particles, exposing palladium cores in the colloidal particles, directly and effectively catalyzing and starting the chemical copper deposition reaction, inducing the chemical copper deposition autocatalytic reaction by the activation of the palladium cores, and enabling the newly generated chemical copper and reaction byproduct hydrogen to be used as a reaction catalyst for catalytic reaction, so as to enable the copper deposition reaction to be continuously carried out, after the treatment of the step, a layer of chemical copper can be deposited on the plate surface or the hole wall;

step three, electroplating: the electroplating tank body is divided into two electroplating tanks by adopting a printed circuit board plating part needing through-hole copper electroplating as a partition board, wherein the surface of electroplating solution in one electroplating tank is higher than the surface of electroplating solution in the other electroplating tank, a pressure difference is formed between the two electroplating tanks, so that the electroplating solution can flow from a high-position electroplating solution tank to a low-position electroplating solution tank through the through-hole, the electroplating solution in the hole is continuously updated, the electroplating solution in the low-position electroplating tank is pumped back to the electroplating tank with the high-position solution tank by a water suction pump to maintain the pressure difference, the through-hole copper electroplating adopts direct current electroplating, the cathode does not need to swing in the electroplating process, and the electroplating solution does not need to be stirred by inflation;

step four, copper precipitation for the second time: adopting the copper deposition method in the second step;

step five, etching: in alkaline environment solution, copper ions are very easy to form copper hydroxide precipitate, enough ammonia water is needed to be added to generate a copper ammonia complex ion group, the occurrence of the precipitate can be inhibited, simultaneously, the original large amount of copper and the continuously dissolved copper form very stable copper ammonia complex ions in the solution, the divalent copper ammonia complex ions can be used as an oxidizing agent to oxidize and dissolve zero-valent metal copper, but cuprous ions appear in the oxidation-reduction reaction process;

step six, solder resist: respectively printing two surfaces of a printed circuit board by adopting solder resist ink through a 68T polyester screen printing plate, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in an oven, cooling to room temperature after baking is finished, printing two surfaces of the cooled printed circuit board by adopting the solder resist ink through the polyester screen printing plate again, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in the oven, cooling to room temperature after baking is finished, and sequentially carrying out solder resist film alignment, exposure and development on the cooled printed circuit board;

step seven, pressing a plate: pressing the plate under the physical principle of high temperature and high pressure with the temperature of 150 ℃ and the pressure of 6kg, and detecting the existing problems;

and step eight, testing, final inspection and shipment.

Preferably, the baking temperature in the sixth step is 75 +/-3 ℃, and the baking time is 15-20 minutes.

Compared with the prior art, the invention has the following beneficial effects:

1. adding second copper deposition on the original flow, electroplating after the first copper deposition to consolidate the copper layer in the through hole, wherein the second copper deposition is mainly used for repairing the problem of leakage deposition and leakage plating caused by the first copper deposition, and because the copper deposition liquid medicine is not easy to permeate and cause leakage deposition due to the small aperture of the through hole, the liquid medicine flowing dislocation chance is increased due to the increase of the first copper deposition, and the leakage deposition problem is completely avoided;

2. the pressing plate before testing is added, the problems that a copper layer is thin due to copper deposition, the copper layer is broken and the like are aged by using a high-temperature high-pressure physical principle (expansion with heat and contraction with cold), so that bad problems are broken, the problem is intercepted during testing, bad outflow is avoided, and the customer complaint rate is changed from 0.6% to 0 by adding the pressing plate;

3. the copper-free defective rate of the holes is reduced from 4-6% to 0.1-0.3%, and the quality is improved by 20 times;

4. the cost is increased a little, but the improvement of the quality makes up the shortage in the aspect.

Drawings

Fig. 1 is a processing flow chart of a processing method of a Mi ni LED printed circuit board with a high thickness-to-diameter ratio according to the present invention.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "both ends", "one end", "the other end", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "connected," and the like are to be construed broadly, such as "connected," which may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, a method for processing a Mi ni LED printed circuit board with a high thickness-to-diameter ratio includes the following steps: step one, drilling: firstly, punching a plurality of pin holes in the short edge position of the copper-coated substrate by using a pin punching machine, then fixing the combined plate with the punched pin holes on a workbench of a numerical control drilling machine, setting the main shaft rotating speed and the cutter dropping speed of the drilling machine, drilling the combined plate, taking the combined plate off the workbench of the numerical control drilling machine after the combined plate is drilled, then withdrawing the pins on the combined plate by using a pin withdrawing machine to obtain the substrate after the holes are drilled, then treating burrs and burrs on the surface of the substrate by using abrasive paper, and then checking the holes drilled on the substrate by using a hole checking machine; step two, depositing copper for the first time: removing oil stain, fingerprints, oxides and dust in holes of the plate surface, enabling the hole walls to be adjusted from negative charges to positive charges, facilitating the adsorption of colloidal palladium in the subsequent process, removing the oxides on the plate surface, coarsening the plate surface, ensuring that a subsequent copper deposition layer has good binding force with base copper of a substrate, and being capable of well adsorbing the colloidal palladium, enabling the positively charged hole walls to effectively adsorb enough colloidal palladium particles with negative charges after the pretreatment alkaline degreasing polarity adjustment, so as to ensure the average, continuity and compactness of the subsequent copper deposition, removing stannous ions coated outside the colloidal palladium particles, exposing palladium cores in the colloidal particles, directly and effectively catalyzing and starting the chemical copper deposition reaction, inducing the chemical copper deposition autocatalytic reaction by the activation of the palladium cores, and enabling the newly generated chemical copper and reaction byproduct hydrogen to be used as a reaction catalyst for catalytic reaction, so as to enable the copper deposition reaction to be continuously carried out, after the treatment of the step, a layer of chemical copper can be deposited on the plate surface or the hole wall; step three, electroplating: the electroplating tank body is divided into two electroplating tanks by adopting a printed circuit board plating part needing through-hole copper electroplating as a partition board, wherein the surface of electroplating solution in one electroplating tank is higher than the surface of electroplating solution in the other electroplating tank, a pressure difference is formed between the two electroplating tanks, so that the electroplating solution can flow from a high-position electroplating solution tank to a low-position electroplating solution tank through the through-hole, the electroplating solution in the hole is continuously updated, the electroplating solution in the low-position electroplating tank is pumped back to the electroplating tank with the high-position solution tank by a water suction pump to maintain the pressure difference, the through-hole copper electroplating adopts direct current electroplating, the cathode does not need to swing in the electroplating process, and the electroplating solution does not need to be stirred by inflation; step four, copper precipitation for the second time: adopting the copper deposition method in the second step; step five, etching: in alkaline environment solution, copper ions are very easy to form copper hydroxide precipitate, enough ammonia water is needed to be added to generate a copper ammonia complex ion group, the occurrence of the precipitate can be inhibited, simultaneously, the original large amount of copper and the continuously dissolved copper form very stable copper ammonia complex ions in the solution, the divalent copper ammonia complex ions can be used as an oxidizing agent to oxidize and dissolve zero-valent metal copper, but cuprous ions appear in the oxidation-reduction reaction process; step six, solder resist: respectively printing two surfaces of a printed circuit board by adopting solder resist ink through a 68T polyester screen printing plate, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in an oven, cooling to room temperature after baking is finished, printing two surfaces of the cooled printed circuit board by adopting the solder resist ink through the polyester screen printing plate again, standing for 15-45 minutes after printing is finished, baking the printed circuit board which is well stood in the oven, cooling to room temperature after baking is finished, and sequentially carrying out solder resist film alignment, exposure and development on the cooled printed circuit board; step seven, pressing a plate: pressing the plate under the physical principle of high temperature and high pressure with the temperature of 150 ℃ and the pressure of 6kg, and detecting the existing problems; step eight, testing, final inspection and shipment; and sixthly, baking at the temperature of 75 +/-3 ℃ for 15-20 minutes.

The invention is to be noted that the invention is a method for processing a Mini LED printed circuit board with high thickness-to-diameter ratio, the Mini LED printed circuit board is added with second copper deposition on the original flow, the copper deposition is carried out after the first copper deposition to consolidate the copper layer in a through hole, the second copper deposition is mainly used for repairing the problem of leakage deposition and leakage plating caused by the first copper deposition, the problem of leakage deposition and leakage plating caused by the first copper deposition is solved completely because the copper deposition liquid medicine is not easy to permeate and the copper deposition liquid medicine is easy to permeate in the through hole with small aperture of the through hole, the increase of the first copper deposition increases the chance of liquid medicine flowing dislocation, the problem of leakage deposition is completely eliminated, the problem that the problem of breaking and non-breaking of the copper layer caused by copper deposition is aged by increasing the high-temperature high-pressure physical principle (thermal expansion and cold shrinkage) before the test, the problem of breaking is caused, the problem of breaking is avoided from poor outflow during the test, the customer complaint rate is changed from 0.6% by increasing the pressing plate, the hole copper-free defect rate is reduced from 4-6% to 0.1-0.3%, the quality is improved by 20 times, the cost is increased by a little, but the improvement of the quality makes up the deficiency.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.