Method for realizing in-hole signal isolation based on chemical copper deposition resisting ink and selective chemical copper deposition process

Abstract

The invention relates to a method for realizing in-hole signal isolation based on chemical copper deposition resisting ink and a selective chemical copper deposition process, which comprises the following steps of: coating the chemical copper deposition resisting ink at preset hole opening positions on two sides of a PCB (Printed Circuit Board) core board to form chemical copper deposition resisting ink film layers; a palladium poisoning agent and a surface active agent for inhibiting palladium adsorption are added into the chemical copper deposition resisting ink; laminating the PCB core board to be separated with other boards to form a pretreated board; performing trepanning treatment on a preset trepanning position of the pretreatment plate to form a via hole; and performing chemical copper deposition treatment on the pre-treated board to form a copper layer on the side wall of the via hole of the pre-treated board, and removing the chemical copper deposition resistant ink film layer from the pre-treated board to form the PCB. Therefore, due to the fact that the palladium poisoning agent and the surface active agent for inhibiting palladium adsorption are added into the anti-electroless copper deposition printing ink, the formed anti-electroless copper deposition printing ink film layer is resistant to attack of chemical copper series liquid medicine, the problem of copper coating on a separation layer can be effectively reduced or eliminated, and in-hole signal separation can be effectively achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board manufacturing, in particular to a method for realizing signal isolation in a hole based on anti-chemical copper deposition ink and selective chemical copper deposition process and application thereof. BACKGROUND

[0002] With the exponential growth of AI computing power, the performance of printed circuit board substrate in high-frequency high-speed signal transmission has reached the limit, and breakthroughs in processing technology are therefore increasingly concerned, among which the stub (short stub) problem of back drilling residue is particularly prominent. In the past, when the transmission rate was relatively low, the industry's safety standard for stub length was relatively loose, but with the popularization of higher-order technology, this standard has been tightened significantly. The current back drilling process is limited by the physical limit of mechanical drill bits, and there will always be a "tail" that is difficult to eliminate, and the industry has clear requirements for the minimum stub (2 mil) for reliability considerations. Today, in the face of higher transmission demands, the traditional back drilling process has been difficult to meet the relevant requirements, and new technological breakthroughs are urgently needed.

[0003] Chinese patent CN 108541150 A discloses a method for realizing signal isolation in a hole by adopting a layer of soluble material on both sides of a PCB core board, exposing and developing to form a PCB isolation board with a pattern layer of soluble material; pressing the PCB core board and the PCB isolation board in a predetermined order to obtain a first pretreated board; according to the position of the pattern layer of soluble material in the PCB isolation board, a via hole coaxially arranged with the pattern layer of soluble material is formed on the first pretreated board; the pattern layer of soluble material in the first pretreated board is removed, and a barrier layer is formed at the corresponding position of the pattern layer of soluble material to obtain a second pretreated board; the second pretreated board is sequentially subjected to copper deposition treatment and electroplating copper treatment; the second pretreated board after electroplating copper treatment is subjected to resin filling treatment to form a PCB board, and the barrier layer makes the PCB board realize the blocking of the ineffective path in the via hole, thereby improving the signal transmission quality. However, the barrier layer formed by the soluble material layer of the anti-electroplating ink covers the area behind the barrier layer formed by the soluble material layer during the copper deposition or electroplating copper process, and there is still a problem of partial copper deposition in the area behind the barrier layer formed by the soluble material layer during the copper deposition process, which cannot realize the blocking of the ineffective path in the via hole, thereby affecting the signal transmission quality.

[0004] Therefore, it is necessary to solve the problem of copper deposition on the barrier layer formed by the soluble material layer. SUMMARY

[0005] Therefore, it is necessary to provide a method for realizing signal isolation in a hole based on anti-chemical copper deposition ink and selective chemical copper deposition process and application thereof, which can realize signal isolation in a hole and reduce the influence of stub residue length.

[0006] The application provides a method for realizing hole signal isolation based on anti-chemical copper plating ink and selective chemical copper plating process, which comprises the following steps. Coating the anti-chemical copper plating ink at the preset hole position on both sides of the PCB core plate to be isolated to form an anti-chemical copper plating ink film layer, wherein the anti-chemical copper plating ink is added with a palladium poison and a surfactant for inhibiting palladium adsorption; the anti-chemical copper plating ink film layer covers the preset hole position, and the diameter of the anti-chemical copper plating ink film layer is larger than that of the preset hole position; Pressing the PCB core plate to be isolated and other plates in a preset order to form a pretreated plate; Hole processing is performed on the preset hole position of the pretreated plate to form a via hole; Chemical copper plating processing is performed on the pretreated plate to form a copper layer at the side wall of the via hole and a copper layer isolation position at the anti-chemical copper plating ink film layer position of the via hole side wall.

[0007] In one of the embodiments, after the copper layer isolation position is formed, the method for realizing hole signal isolation further comprises: removing the anti-chemical copper plating ink film layer from the pretreated plate.

[0008] In one of the embodiments, the palladium poison is at least one of sodium dimethyldithiocarbamate, thiourea, potassium thiocyanate and sodium dithiodipropyl sulfone.

[0009] In one of the embodiments, the surfactant is an anionic surfactant or a cationic surfactant, wherein the anionic surfactant is used in colloidal palladium activated copper plating processing, and the cationic surfactant is used in ionic palladium activated copper plating processing.

[0010] In one of the embodiments, the cationic surfactant is polyvinylimidazolinone.

[0011] In one of the embodiments, in the copper plating processing, the chemical copper plating solution used comprises the following components with the following mass concentrations: chemical copper M agent: 70-110 ml / L, copper ions: 2.2-2.8 g / L, sodium hydroxide: 8-10 g / L, formaldehyde: 4-10 g / L, and the chemical copper M agent comprises the following components with the following mass concentrations: sodium potassium tartrate: 350-500 g / L, nickel sulfate: 15-30 g / L, bipyridine: 50-200 PPM, potassium ferrocyanide: 50-200 PPM, triethanolamine: 0.5-5 g / L, and polyethylene glycol 1000: 0.5-5 g / L. And / or, in the copper plating processing, the temperature of the copper plating processing is 27-35 degrees Celsius, and the processing time is 240-420 seconds.

[0012] In one of the embodiments, the photosensitive ink is an acrylic resin photosensitive ink.

[0013] In one embodiment, the thickness of the anti-chemical copper deposition ink film layer is 20-100 microns; and the diameter of the anti-chemical copper deposition ink film layer is greater than 6 mils relative to the diameter of the pre-set opening position.

[0014] In one embodiment, the mass addition concentration of the palladium poison in the anti-chemical copper deposition ink is 0.2-20 g / kg; and / or, the mass addition concentration of the surfactant is 0.2-20 g / kg.

[0015] In one embodiment, the mass addition concentration of the palladium poison in the anti-chemical copper deposition ink is 5-10 g / kg; and / or, the mass addition concentration of the surfactant is 5-10 g / kg.

[0016] In one embodiment, after the opening treatment and before the copper deposition treatment, the method for achieving signal isolation in the hole further comprises the following steps: sequentially performing bulk tank treatment, glue removal treatment, neutralization treatment, hole finishing treatment, micro-etching treatment, pre- immersion treatment, activation treatment, and acceleration treatment on the pre-processed plate. In one embodiment, in the bulk tank treatment, a bulk tank solution is used for treatment, preferably, the bulk tank solution comprises the following components at the following concentrations: SW1001: 80-120 ml / L, NaOH: 40-50 g / L; preferably, the temperature of the bulk tank treatment is 75-85 degrees Celsius, and the treatment time is 60-120 seconds; for example, the composition of SW1001 comprises: diethylene glycol monobutyl ether 450 g / L and 1,4-butanediol 160 g / L.

[0017] In one embodiment, in the glue removal treatment, a glue removal solution is used for treatment, preferably, the glue removal solution comprises the following components at the following concentrations: NaOH: 40-50 g / L, sodium permanganate NaMnO4: 60-90 g / L, hexavalent manganese MnO4 2- : ≤30 g / L, preferably, the temperature of the glue removal treatment is 80-88 degrees Celsius, and the treatment time is 150-240 seconds. In one embodiment, in the neutralization treatment, a neutralization solution is used for treatment, preferably, the neutralization solution comprises the following components at the following concentrations: H2SO4: 20-50 ml / L, NU3002: 50-100 ml / L, preferably, the temperature of the neutralization treatment is 35-45 degrees Celsius, and the treatment time is 50-70 seconds. In one embodiment, in the hole finishing treatment, a hole finishing solution is used for treatment, preferably, the hole finishing solution comprises the following components at the following concentrations: alkalinity: 0.13-0.17 N, preferably, sodium hydroxide is selected to adjust the alkalinity, preferably, the temperature of the hole finishing treatment is 50-60 degrees Celsius, and the treatment time is 50-70 seconds. In one of the embodiments, in the micro-etching process, a micro-etching solution is used for the process, preferably, the micro-etching solution comprises the following concentrations of components: 50% H2SO4: 25-45ml / L, SPS: 130-170g / L, preferably, the temperature of the micro-etching process is 25-30 degrees Celsius, and the processing time is 30-40 seconds; In one of the embodiments, in the pre-dipping process, a pre-dipping solution is used for the process, preferably, the pre-dipping solution comprises the following concentrations of components: PD3004: 30-70ml / L, preferably, the temperature of the pre-dipping process is room temperature, and the processing time is 10-20 seconds; In one of the embodiments, in the activation process, an activation solution is used for the process, preferably, the activation solution comprises Pd content: 60-120ppm, and its pH is 9-9.5, preferably, the temperature of the activation process is 45-55 degrees Celsius, and the processing time is 50-70 seconds; In one of the embodiments, in the acceleration process, a reducing solution is used for the process, preferably, the reducing solution comprises the following concentrations of components: boric acid: 10g / L, 10% DMAB: 1% volume concentration, preferably, the temperature of the acceleration process is 25-30 degrees Celsius, and the processing time is 25-35 seconds.

[0018] In one of the embodiments, after the pressing process step, the method for achieving signal isolation in holes further comprises: baking the pre-processed board.

[0019] The application also provides a printed circuit board prepared by the method for achieving signal isolation in holes based on the anti-chemical copper plating ink and selective chemical copper plating process according to any one of the above embodiments.

[0020] The method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process realizes signal isolation in holes by coating the anti-chemical copper plating ink on both sides of the PCB core plate to form an anti-chemical copper plating ink film layer. The anti-chemical copper plating ink contains a palladium poison and a surfactant for inhibiting palladium adsorption. The anti-chemical copper plating ink film layer covers the preset hole position, and the edges of the anti-chemical copper plating ink film layer protrude outward relative to the edges of the preset hole position. In the subsequent hole plating process, the anti-chemical copper plating ink film layer formed by the palladium poison and the surfactant for inhibiting palladium adsorption can resist the attack of chemical copper series reagents, and the area of the anti-chemical copper plating ink film layer is not plated with copper, thereby effectively reducing or eliminating the copper plating problem of the isolation layer, effectively realizing signal isolation in holes, and reducing the stub stub length. The method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process of the application can eliminate the stub from the root. Moreover, the anti-chemical copper plating ink film layer formed by the anti-chemical copper plating ink can meet the demand for high-frequency and high-speed transmission of 224G / 448G. In the application, the anti-chemical copper plating ink film layer can block copper plating in the subsequent chemical copper plating process, thereby realizing selective chemical copper plating process and selective isolation in the anti-chemical copper plating ink film layer.

[0021] The application realizes selective isolation of copper layer in holes by embedding the anti-chemical copper plating ink film layer in the hole position specific layer based on the anti-chemical copper plating ink. Thus, the effect of replacing back drilling is achieved, and the stub residue can be smaller or even 0. Moreover, the method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process has significant technical advantages compared with the traditional mechanical back drilling technology. First, the copper layer isolation position can be accurately controlled by a chemical method, the residual stub value can be smaller, and the batch consistency is significantly improved. Second, the hole wall roughness caused by mechanical drilling is eliminated, and the signal transmission loss is reduced by 5-10%. Third, the back drilling safety distance is not required, and smaller hole spacing design can be realized. Fourth, the traditional back drilling blind section can be reused for wiring, and the wiring utilization rate of high-density interconnection boards is improved. Finally, the back drilling and burr removal processes are omitted, the process flow is shortened, and the production efficiency is improved. The technology is particularly suitable for processing of high-frequency and high-speed PCBs. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 FIG. 1 is a schematic diagram of the method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process of an embodiment of the application after the PCB core plate is coated with the anti-chemical copper plating ink film layer. Figure 2A schematic diagram of a pretreatment plate after opening holes in the method for realizing hole signal isolation based on the anti-chemical copper deposition ink and the selective chemical copper deposition process of an embodiment of the present application; Figure 3 A schematic diagram of a pretreatment plate after opening holes in the method for realizing hole signal isolation based on the anti-chemical copper deposition ink and the selective chemical copper deposition process of an embodiment of the present application; Figure 4 A schematic diagram of a pretreatment plate after copper deposition treatment in the method for realizing hole signal isolation based on the anti-chemical copper deposition ink and the selective chemical copper deposition process of an embodiment of the present application; Figure 5 A schematic diagram of a pretreatment plate after removing the anti-chemical copper deposition ink film layer in the method for realizing hole signal isolation based on the anti-chemical copper deposition ink and the selective chemical copper deposition process of an embodiment of the present application; Figure 6a A slice picture of a pretreatment plate before removing the anti-chemical copper deposition ink film layer in embodiment 6 of the present application; Figure 6b A schematic diagram of a pretreatment plate after removing the anti-chemical copper deposition ink film layer in embodiment 6 of the present application; Figure 6a An enlarged view at the rectangular frame; Figure 7a A slice picture of a pretreatment plate after removing the anti-chemical copper deposition ink film layer in embodiment 6 of the present application; Figure 7b A schematic diagram of a pretreatment plate after removing the anti-chemical copper deposition ink film layer in embodiment 6 of the present application; Figure 7a An enlarged view at the rectangular frame. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, in order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below. In the following description, a lot of specific details are set forth in order to facilitate a full understanding of the present application, and the preferred embodiments of the present application are given in the accompanying drawings. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. The present application can be implemented in many different ways from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs. The terms used herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] The application provides a method for realizing hole signal isolation based on anti-chemical copper deposition ink and selective chemical copper deposition process. The method realizes hole signal isolation of a printed circuit board (PCB) by adopting an anti-chemical copper deposition ink film layer process and a chemical copper deposition process.

[0025] In an embodiment, the method for realizing hole signal isolation based on anti-chemical copper deposition ink and selective chemical copper deposition process comprises the following steps S1 to S5. S1: coating anti-chemical copper deposition ink at the preset hole position on both sides of the PCB core board to be isolated to form an anti-chemical copper deposition ink film layer, wherein the anti-chemical copper deposition ink is added with a palladium poison and a surface active agent for inhibiting palladium adsorption; the anti-chemical copper deposition ink film layer covers the preset hole position, and the edge of the anti-chemical copper deposition ink film layer protrudes outward relative to the edge of the preset hole position; it can also be understood that the coating shape of the anti-chemical copper deposition ink film layer is circular, the preset hole position is also circular, and the diameter of the anti-chemical copper deposition ink film layer is larger than that of the preset hole position.

[0026] It should be understood that one PCB usually comprises a multi-layer board, which is realized by alternately stacking core boards, PPs, copper foils and the like, and is interconnected by through holes. In the pressing process of the multi-layer board, the boards are bonded by prepreg. In the embodiment, the PCB core board to be isolated, that is, the PCB core board which needs to be electrically isolated from other adjacent board layers in the corresponding through hole or does not need to set a copper column. The PCB core board has a conductive copper layer on both sides, and the related conductive copper layer has a corresponding circuit pattern. How to prepare a PCB core board by a copper-clad plate can be referred to the prior art, and the application will not be described here. Please refer to Figure 1 which is a schematic view after the anti-chemical copper deposition ink film layer 200 is coated on both sides of the PCB core board 100. The PCB core board comprises a base plate 110 and a conductive copper layer 120 on both sides, and the conductive copper layer forms a preset circuit pattern.

[0027] In this embodiment, the anti-chemical copper deposition ink film layer is formed by coating the anti-chemical copper deposition ink at the pre-set opening position on both sides of the PCB core board. For example, the anti-chemical copper deposition ink is a photosensitive ink, which is cured by light irradiation after adding the anti-chemical copper deposition ink to form the anti-chemical copper deposition ink film layer. The anti-chemical copper deposition ink film layer is resistant to attack by chemical copper series reagents, ensuring that the anti-chemical copper deposition ink film layer area is not copper-plated. In this embodiment, the anti-chemical copper deposition ink contains a palladium poison and a surfactant that inhibits palladium adsorption; this allows the anti-chemical copper deposition ink film layer to resist attack by chemical copper series reagents in subsequent chemical copper processes, thereby avoiding or reducing copper plating on the anti-chemical copper deposition ink film layer. It should be further noted that if too much copper is plated on the anti-chemical copper deposition ink, subsequent removal of the anti-chemical copper deposition ink film layer by bleaching will not be possible, and the signal in the hole will not be effectively blocked. By optimizing the anti-chemical copper deposition ink formula, the application adds a palladium poison and a surfactant that inhibits palladium adsorption. The palladium poison is mainly used to inhibit the catalytic activity of palladium in the activation solution in the chemical copper process, thereby precisely blocking copper deposition in non-conductive areas. For example, the palladium poison is at least one of sodium dimethyldithiocarbamate, thiourea, potassium thiocyanate, and sodium polydithiodipropyl sulfonate, but is not limited thereto. For example, the surfactant is an anionic surfactant or a cationic surfactant. The anionic surfactant is used to adapt to the colloidal palladium activation copper plating process, and the anionic surfactant is used to maintain a negative charge characteristic and generate electrostatic repulsion with negatively charged colloidal palladium to inhibit palladium adsorption. For example, the anionic surfactant is an alkyl sulfonate (such as sodium dodecyl benzene sulfonate), a fatty acid salt (such as sodium stearate), a sulfate salt (such as sodium lauryl polyoxyethylene ether sulfate), or the like. The cationic surfactant is used in the ionic palladium activation copper plating process, and the cationic surfactant is used to make the hole wall have a positive charge characteristic to repel positively charged ionic palladium (such as Pd 2+ ), thereby reducing palladium deposition. For example, the cationic surfactant is cetyltrimethylammonium bromide (CTAB), octadecyltrimethylammonium chloride, imidazoline derivatives, or the like. Preferably, the cationic surfactant is polyvinylimidazoline ketone. The addition of the additive to the anti-chemical copper deposition ink film layer enhances the alkali resistance of the anti-chemical copper deposition ink film layer, and the anti-chemical copper deposition ink film layer does not fall off in an alkaline copper tank within two hours.

[0028] The application adds a palladium poison and a surfactant that inhibits palladium adsorption in the photosensitive ink to inhibit the deposition of the anti-chemical copper series reagent in the subsequent chemical copper process, thereby realizing hole signal isolation. By covering the pre-designed hole position with the anti-chemical copper deposition ink film layer, and protruding the edge of the anti-chemical copper deposition ink film layer outward relative to the edge of the pre-designed hole position, or in other words, the diameter of the anti-chemical copper deposition ink film layer is larger than the diameter of the pre-designed hole position, it is convenient for the subsequent hole forming process to form an upper copper isolation layer around the via hole with the anti-chemical copper deposition ink film layer, thereby avoiding or reducing the deposition of chemical copper to form an isolation layer. By coating the anti-chemical copper deposition ink on both sides of the PCB core board to be isolated to form an anti-chemical copper deposition ink film layer, wherein the anti-chemical copper deposition ink is added with a palladium poison and a surfactant that inhibits palladium adsorption, the anti-chemical copper deposition ink film layer covers the pre-designed hole position, and the edge of the anti-chemical copper deposition ink film layer protrudes outward relative to the edge of the pre-designed hole position; during the subsequent hole forming and copper deposition process, the anti-chemical copper deposition ink is added with a palladium poison and a surfactant that inhibits palladium adsorption, thereby forming an anti-chemical copper deposition ink film layer that is resistant to acid, alkali, and oxidants, resistant to high temperature (150 degrees), resistant to chemical copper series reagent attack, and the anti-chemical copper deposition ink film layer area does not deposit copper, which can effectively reduce or eliminate the copper deposition problem of the isolation layer, thereby further reducing the stub stub length and eliminating the stub stub from the root. Moreover, the application realizes selective hole isolation by forming an anti-chemical copper deposition ink film layer with anti-chemical copper deposition ink, which can realize 0 stub and meet the demand for 224G / 448G high-frequency high-speed transmission.

[0029] S2: according to a predetermined order, press the PCB core board to be isolated and other board materials to form a pretreated board; Please refer to Figure 2 After coating the anti-chemical copper deposition ink on both sides of the PCB core board 100 at the pre-designed hole position to form an anti-chemical copper deposition ink film layer 200, the PCB core board is pressed with other board materials to form a pretreated board. The pressing with other board materials can be performed according to the design of the PCB. The PCB usually includes a multilayer board, which is realized by alternately stacking core boards, PPs, and copper foils, etc. The process of pressing the PCB core board with other board materials is described in the prior art, which will not be repeated here. For example, after pressing, the pretreated board is subjected to a baking step, for example, the baking temperature is 160 degrees Celsius and the time is 120 minutes. For example, the other board materials include a PCB core board, a copper foil, a prepreg, etc. The board materials are bonded by the prepreg 300.

[0030] S3: hole processing is performed on the pre-designed hole position of the pretreated board to form a via hole; Please refer to Figure 3 Hole processing is performed on the pre-designed hole position of the pretreated board to form a via hole 400.

[0031] S4: performing a chemical copper deposition treatment on the pretreated board to form a copper layer at the side wall of the via of the pretreated board, and to form a copper layer separation position at the position of the chemical copper deposition resistant ink film layer on the side wall of the via; Please refer to Figure 4 , by performing a chemical copper deposition treatment on the pretreated board after the via is opened, a copper layer 410 is formed at the side wall of the via 400 of the pretreated board, and a copper layer separation position 420 is formed at the position of the chemical copper deposition resistant ink film layer 200 on the side wall of the via. In this application, due to the presence of the chemical copper deposition resistant ink film layer 200 in the prepreg, the via 400 cannot form a copper layer at the side wall position of the chemical copper deposition resistant ink film layer 200, so that a separation gap is formed between the copper layers, that is, a copper layer separation position 420 is formed, thereby forming a separation of the copper layer, and further realizing the separation of the signal in the hole. For example, in the copper deposition process, the chemical copper deposition solution used includes the following mass concentrations of each component: chemical copper M agent: 70-110 ml / L, copper ions: 2.2-2.8 g / L, sodium hydroxide: 8-10 g / L, reducing agent: 4-10 g / L, the chemical copper M agent includes the following mass concentrations of each component: potassium sodium tartrate: 350-500 g / L, nickel ions: 15-30 g / L, bipyridine: 50-200 PPM, potassium ferrocyanide: 50-200 PPM, triethanolamine: 0.5-5 g / L, polyethylene glycol 1000: 0.5-5 g / L, the chemical copper M agent is prepared in advance, and the chemical copper M agent, sodium hydroxide, copper ions and reducing agent are mixed before use; for example, in the copper deposition process, the temperature of the copper deposition process is 27-35 degrees Celsius, and the processing time is 240-420 seconds. Again, the substance that provides copper ions is copper sulfate, copper chloride and other copper salts, so that the deposited copper thickness can reach 0.4-0.7 microns, and the control accuracy is good. Again, the nickel ions are nickel sulfate.

[0032] S5: removing the chemical copper deposition resistant ink film layer from the pretreated board to form a PCB board.

[0033] Please refer to Figure 5 and compare Figure 4 , after removing the chemical copper deposition resistant ink film layer 200 in Figure 4 , a PCB board with signal separation in the hole is formed. For example, chemical solvent can be used for dissolution and removal, for example, a film stripping solution is used to remove the chemical copper deposition resistant ink film layer from the pretreated board, wherein the film stripping solution is 3-5% sodium hydroxide solution, the soaking time is 2-3 minutes, and the film stripping temperature is 40-50 degrees Celsius. In this way, the chemical copper deposition resistant ink film layer can be removed well, thereby better ensuring the signal separation in the hole.

[0034] The method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process is realized by coating the anti-chemical copper plating ink on both sides of the PCB core plate to be isolated to form an anti-chemical copper plating ink film layer. The anti-chemical copper plating ink contains a palladium poison and a surfactant for inhibiting palladium adsorption. The anti-chemical copper plating ink film layer covers the preset hole position, and the diameter of the anti-chemical copper plating ink film layer is larger than the diameter of the edge of the preset hole position. In the subsequent hole plating process, the anti-chemical copper plating ink film layer formed by the addition of the palladium poison and the surfactant for inhibiting palladium adsorption can resist the attack of the chemical copper series reagent, and the area of the anti-chemical copper plating ink film layer is not plated with copper, effectively reducing or eliminating the copper plating problem of the isolation layer, and realizing the effective isolation of the signal in the hole. Moreover, the present application can realize 0 stub by stubbing the residual stub length and eliminating the residual stub from the root for the traditional back drilling technology. Moreover, the present application realizes selective isolation in holes by the anti-chemical copper plating ink and the selective chemical copper plating process, realizes 0 stub, and can meet the demand for high-frequency and high-speed transmission of 224G / 448G.

[0035] The present application realizes selective isolation of the copper layer in the hole by embedding the anti-chemical copper plating ink film layer in the hole position specific layer through the anti-chemical copper property of the anti-chemical copper plating ink film layer, thereby achieving the effect of replacing back drilling and obtaining smaller or even 0 stub. Moreover, the method for realizing signal isolation in holes based on the anti-chemical copper plating ink and the selective chemical copper plating process provided by the present application has significant technical advantages compared with the traditional mechanical back drilling technology. First, the copper layer isolation position can be accurately controlled by a chemical method, the residual stub value can be smaller, and the batch consistency is significantly improved. Second, the hole wall roughness caused by mechanical drilling is eliminated, and the signal transmission loss is reduced by 5-10%. Third, the back drilling safety distance is not required, and smaller hole spacing design can be realized. Fourth, the traditional back drilling blind section can be reused for wiring, and the wiring utilization rate of the high-density interconnection board is improved. Finally, the back drilling and burr cleaning processes are omitted, the process flow is shortened, and the production efficiency is improved. The technology is particularly suitable for the processing of high-frequency PCBs.

[0036] In an embodiment, the anti-chemical copper plating ink is an acrylic resin photosensitive ink. For example, the anti-chemical copper plating ink includes the following components: methyl methacrylate resin, tert-butyl o-cresol, 2,3,5,6-tetrafluoro-4-trifluoromethyl benzyl bromide, melamine, dicyandiamide, chromium sesquioxide, silicon dioxide, polyether modified trimethyl trisiloxane, isopropyl alcohol, divalent acid ester and toluene, and polydimethylsilane. In another example, the anti-chemical copper plating ink includes the following components with the following mass concentrations: Table 1 Composition of photosensitive ink Thus, by using the anti-chemical copper deposition ink as above, and in combination with the addition of a palladium poison and a surfactant that inhibits the adsorption of palladium, the problem of copper deposition of the anti-chemical copper deposition ink film layer can be further reduced, and the signal in the hole can be further blocked. Moreover, by using the anti-chemical copper deposition ink as above to form an anti-chemical copper deposition ink film layer on a PCB core plate, the anti-chemical copper deposition ink film layer can resist attack by chemical copper series chemicals and not deposit copper. In particular, the ink has high sensitivity and is suitable for DI exposure machine processing, and the preparation process of the anti-chemical copper deposition ink film layer is relatively convenient.

[0037] In an embodiment, the thickness of the anti-chemical copper deposition ink film layer is 20 microns to 100 microns; and the diameter of the anti-chemical copper deposition ink film layer is greater than the diameter of the pre-set opening position by more than 6 mils. In this way, the signal blocking process in the hole can be better achieved.

[0038] In an embodiment, the mass addition concentration of the palladium poisoning agent in the chemical copper deposition resistant ink is 0.2-20 g / kg; and / or, the mass addition concentration of the surfactant is 0.2-20 g / kg. Preferably, the mass addition concentration of the palladium poisoning agent in the chemical copper deposition resistant ink is 5-10 g / kg; and / or, the mass addition concentration of the surfactant is 5-10 g / kg. In this way, by using the palladium poisoning agent and the surfactant in the above mass addition concentrations, on the one hand, the alkali resistance of the chemical copper deposition resistant ink film layer can be enhanced, and the chemical copper deposition resistant ink film layer will not be peeled off in the alkaline copper tank for 2 hours; on the other hand, the copper deposition can also be inhibited, so that the copper deposition area of the chemical copper deposition resistant ink film layer is less than 10%. The applicant has found through experiments that, with the addition of polyvinyl imidazoline ketone (PVI) in the chemical copper deposition resistant ink, the adsorption amount of ionic palladium is reduced; at the same time, the addition of the palladium poisoning agent makes the palladium atoms adsorbed on the surface of the ink lose activity, so as to not be able to play a catalytic role in copper plating. Preferably, the mass addition concentration of the palladium poisoning agent in the chemical copper deposition resistant ink is 10 g / kg; and the mass addition concentration of the surfactant is 10 g / kg. In this way, the applicant has found that, by using the above mass addition concentrations of the palladium poisoning agent and the surfactant, especially in combination with the surfactant being polyvinyl imidazoline ketone, the photosensitive ink includes the following components: methacrylic acid resin, tert-butyl o-cresol, 2,3,5,6-tetrafluoro-4-trifluoromethyl benzyl bromide, melamine, dicyandiamide, chromium sesquioxide, silicon dioxide, polyether modified trimethyl trisiloxane, isopropyl alcohol, divalent acid ester and toluene, and polydimethylsilane, the chemical copper deposition resistant ink film layer can be almost free of copper deposition. In particular, by controlling the copper deposition area of the chemical copper deposition resistant ink film layer to be less than 10%, the subsequent film peeling process of the chemical copper deposition resistant ink film layer is relatively smooth, which is conducive to effectively blocking the signal in the hole. On the contrary, when the copper deposition area of the chemical copper deposition resistant ink film layer is more than 10%, there will be a certain signal interference. By setting the mass addition concentration of the palladium poisoning agent in the chemical copper deposition resistant ink to be 5-10 g / kg; and the mass addition concentration of the surfactant to be 5-10 g / kg, the copper deposition area of the chemical copper deposition resistant ink film layer can be well controlled to be less than 10.1%, the film peeling process is smooth, which is conducive to effectively blocking the signal in the hole.

[0039] In one of the embodiments, after the hole opening treatment and before the copper deposition treatment, the method for achieving signal isolation in the hole further comprises the following steps: sequentially performing bulk tank treatment, glue removal treatment, neutralization treatment, hole finishing treatment, micro-etching treatment, pre- immersion treatment, activation treatment, and acceleration treatment on the pre-processed board; of course, the anti-chemical copper ink film layer is not affected by the full curing in this step. The bulk tank treatment is used to swell the conventional hole wall resin, facilitate glue removal, and facilitate subsequent copper deposition on the hole wall. The glue removal treatment is used to remove the residue (glue residue) of the high-temperature molten resin in the drilling, preventing poor connection between the inner copper ring and the hole copper. The neutralization treatment is used to remove the residual oxidizing agent. The hole finishing treatment is used to make the hole wall hydrophilic and positively charged, enhancing the chemical copper adhesion. The micro-etching treatment is used to roughen the copper surface, improving the bonding force. The pre- immersion treatment, activation treatment, and acceleration treatment are used to deposit a palladium catalytic layer, facilitating subsequent chemical copper deposition in the copper deposition treatment. For example, in the bulk tank treatment, a bulk tank solution is used for treatment, for example, the bulk tank solution includes the following concentrations of each component: SW1001: 80-120 ml / L, NaOH: 40-50 g / L; for example, the temperature of the bulk tank treatment is 75-85 degrees Celsius, and the treatment time is 60-120 seconds; for example, in the glue removal treatment, a glue removal solution is used for treatment, for example, the glue removal solution includes the following concentrations of each component: NaOH: 40-50 g / L, sodium permanganate NaMnO4: 60-90 g / L, hexavalent manganese MnO4 2-:≤30g / L, for example, the temperature of the glue-removing treatment is 80-88 degrees Celsius, and the treatment time is 150-240 seconds; for example, in the neutralization treatment, a neutralization liquid is used for the treatment, for example, the neutralization liquid includes the following concentrations of components: H2SO4: 20-50 ml / L, NU3002: 50-100 ml / L, for example, the temperature of the neutralization treatment is 35-45 degrees Celsius, and the treatment time is 50-70 seconds; for example, in the whole-hole treatment, a whole-hole liquid is used for the treatment, for example, the whole-hole liquid includes the following concentrations of components: alkalinity: 0.13-0.17 N, for example, sodium hydroxide is selected to adjust the alkalinity, for example, the temperature of the whole-hole treatment is 50-60 degrees Celsius, and the treatment time is 50-70 seconds; for example, in the etching treatment, an etching liquid is used for the treatment, for example, the etching liquid includes the following concentrations of components: 50% H2SO4: 25-45 ml / L, SPS: 130-170 g / L, for example, the temperature of the etching treatment is 25-30 degrees Celsius, and the treatment time is 30-40 seconds; for example, in the pre- immersion treatment, a pre- immersion liquid is used for the treatment, for example, the pre- immersion liquid includes the following concentration of components: PD3004: 30-70 ml / L, for example, the temperature of the pre- immersion treatment is room temperature, and the treatment time is 10-20 seconds; for example, in the activation treatment, an activation liquid is used for the treatment, for example, the activation liquid includes Pd content: 60-120 ppm, and its pH is 9.0-9.5, for example, the temperature of the activation treatment is 45-55 degrees Celsius, and the treatment time is 50-70 seconds; for example, in the acceleration treatment, a reduction liquid is used for the treatment, for example, the reduction liquid includes the following concentrations of components: boric acid: 10 g / L, 10% DMAB: 1% by volume, for example, the temperature of the acceleration treatment is 25-30 degrees Celsius, and the treatment time is 25-35 seconds. In this way, after the pre- treatment plate is sequentially subjected to the bulk slot treatment, the glue-removing treatment, the neutralization treatment, the whole-hole treatment, the etching treatment, the pre- immersion treatment, the activation treatment, and the acceleration treatment, the subsequent copper deposition treatment can be better performed, the copper deposition on the chemical-resistance copper deposition ink film layer is less, and the effective isolation of the hole signal is facilitated. For example, in the operation of sequentially performing the bulk slot treatment, the glue-removing treatment, the neutralization treatment, the whole-hole treatment, the etching treatment, the pre- immersion treatment, the activation treatment, and the acceleration treatment on the pre- treatment plate, overflow water washing and fresh water washing are respectively performed between the steps.

[0040] The application also provides a printed circuit board prepared by the method for realizing hole signal isolation based on the chemical-resistance copper deposition ink and the selective chemical copper deposition process according to any one of the above embodiments.

[0041] The method for realizing signal isolation in holes based on the anti-chemical copper deposition ink and the selective chemical copper deposition process realizes the signal isolation in holes by coating the anti-chemical copper deposition ink on both sides of the PCB core plate to be isolated to form an anti-chemical copper deposition ink film layer, wherein the anti-chemical copper deposition ink is added with a palladium poison and a surfactant for inhibiting palladium adsorption, the anti-chemical copper deposition ink film layer covers the preset hole position, and the diameter of the anti-chemical copper deposition ink film layer is larger than the diameter of the edge of the preset hole position; in the subsequent hole copper deposition process, the anti-chemical copper deposition ink film layer formed by adding the palladium poison and the surfactant for inhibiting palladium adsorption in the anti-chemical copper deposition ink can resist the attack of the chemical copper series reagent, the copper deposition on the anti-chemical copper deposition ink film layer area is effectively reduced or eliminated, the copper deposition on the isolation layer is further ensured, and the effective isolation of the signal in the hole is ensured. Moreover, the anti-chemical copper deposition ink film layer formed by the anti-chemical copper deposition ink can meet the demand for high-frequency and high-speed transmission of 224G / 448G.

[0042] The anti-chemical copper deposition ink film layer formed by the anti-chemical copper deposition ink can meet the demand for high-frequency and high-speed transmission of 224G / 448G.

[0043] The method for realizing signal isolation in holes based on the anti-chemical copper deposition ink and the selective chemical copper deposition process realizes the signal isolation in holes by coating the anti-chemical copper deposition ink on both sides of the PCB core plate to be isolated to form an anti-chemical copper deposition ink film layer, wherein the anti-chemical copper deposition ink is added with a palladium poison and a surfactant for inhibiting palladium adsorption, the anti-chemical copper deposition ink film layer covers the preset hole position, and the diameter of the anti-chemical copper deposition ink film layer is larger than the diameter of the edge of the preset hole position; in the subsequent hole copper deposition process, the anti-chemical copper deposition ink film layer formed by adding the palladium poison and the surfactant for inhibiting palladium adsorption in the anti-chemical copper deposition ink can resist the attack of the chemical copper series reagent, the copper deposition on the anti-chemical copper deposition ink film layer area is effectively reduced or eliminated, the copper deposition on the isolation layer is further ensured, and the effective isolation of the signal in the hole is ensured. Moreover, the anti-chemical copper deposition ink film layer formed by the anti-chemical copper deposition ink can meet the demand for high-frequency and high-speed transmission of 224G / 448G.

[0044] Embodiment 1 The method for realizing hole signal isolation based on anti-chemical copper deposition ink and selective chemical copper deposition process comprises the following steps: applying anti-chemical copper deposition ink to form an anti-chemical copper deposition ink film layer at the pre-set opening position on both sides of the PCB core plate to be isolated, wherein the thickness of the anti-chemical copper deposition ink film layer is 20 microns; the diameter of the anti-chemical copper deposition ink film layer is greater than the diameter of the pre-set opening position by more than 6 mil; the anti-chemical copper deposition ink is a photosensitive ink, and the anti-chemical copper deposition ink adopts the component ratio as shown in Table 1. The added palladium poison in the anti-chemical copper deposition ink is thiourea, and the added surfactant is a cationic surfactant, which is polyvinylimidazolinone (PVI). The added concentration of polyvinylimidazolinone in the anti-chemical copper deposition ink is 20 g / kg, and the added concentration of thiourea is 1 g / kg. According to the pre-set order, the PCB core plate to be isolated and other plates are pressed to form a pre-treatment plate. The pre-set opening position of the pre-treatment plate is processed to form a via hole. The pre-treatment plate is subjected to chemical copper deposition treatment to form a copper layer at the side wall of the via hole of the pre-treatment plate, and a copper layer isolation position is formed at the position of the anti-chemical copper deposition ink film layer on the side wall of the via hole. The pre-treatment plate is removed from the anti-chemical copper deposition ink film layer to form a PCB plate.

[0045] Then, the via hole of the PCB plate is sliced, the copper filling rate of the anti-chemical copper deposition ink film layer region is visually observed, and the copper filling rate is estimated. The results are shown in Table 2.

[0046] Examples 2 to 6 The difference between Example 1 and Example 2 is the added concentration of polyvinylimidazolinone and thiourea in the photosensitive ink, and the added concentration is shown in Table 2.

[0047] Comparative Example 1 The difference between Example 1 and Comparative Example 1 is that polyvinylimidazolinone and thiourea are not added to the photosensitive ink.

[0048] Table 2: Added concentration of polyvinylimidazolinone and thiourea in Examples 1 to 6 and detection results As can be seen from the above, the method for realizing hole signal blocking provided by the anti-chemical copper deposition ink film layer process of the application can significantly reduce the copper deposition of the anti-chemical copper deposition ink film layer after adding the surfactant and the palladium poison, compared with the comparative example 1 without adding the surfactant and the palladium poison. As can be seen from the experiment, with the addition of the polyvinylimidazolinone in the ink, the adsorption amount of the ionic palladium is reduced; at the same time, the addition of the palladium poison makes the palladium atoms adsorbed on the surface of the ink lose activity, so as to not play a catalytic role in copper plating. Especially in the embodiment 6, the mass addition concentration of the palladium poison is 10 g / kg; the mass addition concentration of the surfactant is 10 g / kg, so that the anti-chemical copper deposition ink film layer is almost not deposited with copper.

[0049] The PCB board of the embodiment 6 is subjected to slicing and micro-slicing metallographic observation, the PCB board of the embodiment 6 is subjected to slicing before and after the anti-chemical copper deposition ink film layer is removed, and the slicing analysis results of the PCB board before the anti-chemical copper deposition ink film layer is removed are shown in Figure 6a and Figure 6b The slicing analysis results of the PCB board after the anti-chemical copper deposition ink film layer is removed are shown in Figure 7a and Figure 7b . Among them Figure 6b is Figure 6a an enlarged view at the rectangular box, Figure 7b is Figure 7a an enlarged view at the rectangular box. The blue mark in them is the anti-chemical copper deposition ink film layer. As can be seen by comparing Figure 7b and Figure 6b , before the anti-chemical copper deposition ink film layer is removed, the anti-chemical copper deposition ink film layer has a slight copper deposition phenomenon, but after the anti-chemical copper deposition ink film layer is removed, as can be seen from Figure 7b , the corresponding area after the anti-chemical copper deposition ink film layer is removed does not have obvious copper deposition, indicating that the anti-chemical copper deposition ink film layer has a good blocking effect.

[0050] The method for realizing signal isolation in holes based on the anti-chemical copper deposition ink and the selective chemical copper deposition process coats the anti-chemical copper deposition ink on both sides of the PCB core plate to be isolated to form an anti-chemical copper deposition ink film layer, wherein the anti-chemical copper deposition ink is added with a palladium poison and a surfactant for inhibiting palladium adsorption, the anti-chemical copper deposition ink film layer covers the preset hole position, and the diameter of the anti-chemical copper deposition ink film layer is larger than that of the preset hole position. In the subsequent hole copper deposition process, the anti-chemical copper deposition ink film layer formed by adding the palladium poison and the surfactant for inhibiting palladium adsorption in the anti-chemical copper deposition ink can resist the attack of chemical copper series reagent, the copper deposition on the anti-chemical copper deposition ink film layer area is effectively reduced or eliminated, the problem of copper deposition on the isolation layer is solved, and the signal isolation in holes is realized. Moreover, the anti-chemical copper deposition ink film layer formed by the anti-chemical copper deposition ink realizes selective isolation in holes, and compared with the traditional back drilling technology, the present application can realize 0 stub and meet the demand of 224G / 448G high-frequency high-speed transmission.

[0051] The present application realizes selective isolation of copper layer in holes by embedding the anti-chemical copper deposition ink film layer in the hole position specific layer through the anti-chemical copper property of the anti-chemical copper deposition ink film layer. Thus, the effect of replacing back drilling is achieved, and smaller stub or even 0 stub is obtained. Moreover, the method for realizing signal isolation in holes based on the anti-chemical copper deposition ink and the selective chemical copper deposition process provided by the present application has significant technical advantages compared with the traditional mechanical back drilling technology: first, the copper layer isolation position is accurately controlled by a chemical method, the residual stub value is smaller, and the batch consistency is significantly improved; second, the hole wall roughness caused by mechanical drilling is eliminated, and the signal transmission loss is reduced by 5-10%; third, the back drilling safety distance is not required, and smaller hole spacing design can be realized; fourth, the traditional back drilling blind section can be reused for wiring, and the wiring utilization rate of high-density interconnection boards is improved; finally, the back drilling and burr cleaning processes are omitted, the process flow is shortened, the production efficiency is improved, and the technology is particularly suitable for high-frequency PCB processing.

[0052] Any technical features in the above-described embodiments can be combined in any manner, and for the sake of brevity, not all possible combinations are described, however, as long as there is no conflict, any combination of the above technical features is deemed to be within the scope of the present disclosure. It should be noted that "in an embodiment", "for example", "for instance", and the like in the present application are intended to serve as examples of the present application, and are not intended to limit the present application. The above-described embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for achieving signal isolation within vias based on anti-chemical copper plating ink and selective chemical copper plating process, characterized in that, Includes the following steps: Anti-chemical copper plating ink is applied to the pre-set opening positions on both sides of the PCB core board to be separated to form an anti-chemical copper plating ink film layer. The anti-chemical copper plating ink contains palladium poisoning agent and surfactant that inhibits palladium adsorption. The anti-chemical copper plating ink film layer covers the pre-set opening positions, and the diameter of the anti-chemical copper plating ink film layer is larger than the diameter of the pre-set opening positions. The PCB core board to be separated is pressed together with other boards in a preset order to form a pre-processed board; The pre-processed plate is perforated at the preset opening position to form a through hole; The pre-treated board is subjected to chemical copper plating treatment to form a copper layer on the via sidewalls and to form copper layer isolation positions at the positions of the anti-chemical copper plating ink film layer on the via sidewalls.

2. The method for achieving signal isolation within a hole according to claim 1, characterized in that, The palladium poisoning agent is at least one of sodium thiocyanate, thiourea, potassium thiocyanate, and sodium polydithiopropane sulfonate. And / or, after forming the copper layer isolation position, the method for achieving in-hole signal isolation further includes: removing the anti-chemical copper plating ink film layer from the pre-treated board.

3. The method for achieving signal isolation within a hole according to claim 1, characterized in that, The surfactant is an anionic surfactant or a cationic surfactant, wherein the anionic surfactant is used in the colloidal palladium-activated copper plating process, and the cationic surfactant is used in the ionic palladium-activated copper plating process.

4. The method for achieving signal isolation within a hole according to claim 3, characterized in that, The cationic surfactant is polyvinylimidazolinone; And / or, in the copper plating process, the chemical copper plating solution used comprises the following components at the following mass concentrations: chemical copper agent M: 70-110 ml / L, copper ions: 2.2-2.8 g / L, sodium hydroxide: 8-10 g / L, formaldehyde: 4-10 g / L, wherein the chemical copper agent M comprises the following components at the following mass concentrations: potassium sodium tartrate: 350-500 g / L, nickel sulfate: 15-30 g / L, bipyridine: 50-200 PPM, potassium ferrocyanide: 50-200 PPM, triethanolamine: 0.5-5 g / L, polyethylene glycol 1000: 0.5-5 g / L; And / or, in the copper plating process, the temperature is 27-35 degrees Celsius and the processing time is 240-420 seconds.

5. The method for achieving signal isolation within a hole according to any one of claims 1 to 4, characterized in that, The anti-chemical copper plating ink is an acrylic resin photosensitive ink.

6. The method for achieving signal isolation within a hole according to claim 5, characterized in that, The thickness of the anti-chemical copper plating ink film is 20 micrometers to 100 micrometers; the diameter of the anti-chemical copper plating ink film is more than 6 mil larger than the diameter of the preset opening position.

7. The method for achieving signal isolation within a hole according to claim 6, characterized in that, The mass concentration of palladium poisoning agent in the anti-chemical copper plating ink is 0.2-20 g / kg; and / or, the mass concentration of surfactant is 0.2-20 g / kg; Preferably, the concentration of palladium poisoning agent in the anti-chemical copper plating ink is 5-10 g / kg; and / or, the concentration of surfactant is 5-10 g / kg.

8. The method for achieving signal isolation within a hole according to claim 7, characterized in that, After the hole opening process and before the copper plating process, the method for achieving signal isolation within the hole further includes the following steps: sequentially performing expansion tank treatment, adhesive removal treatment, neutralization treatment, hole shaping treatment, micro-etching treatment, pre-immersion treatment, activation treatment, and acceleration treatment on the pre-treated board; Preferably, the expansion tank treatment uses an expansion liquid, which preferably comprises the following components at the following concentrations: SW1001: 80-120 ml / L, NaOH: 40-50 g / L; preferably, the expansion tank treatment temperature is 75-85 degrees Celsius, and the treatment time is 60-120 seconds; for example, SW1001 comprises: diethylene glycol monobutyl ether 450 g / L and 1,4-butanediol 160 g / L. Preferably, the degumming process uses a degumming solution, which preferably comprises the following components at the following concentrations: NaOH: 40-50 g / L, sodium permanganate (NaMnO4): 60-90 g / L, and hexavalent manganese (MnO4): 20-30 g / L. 2- The gluconate content is ≤30g / L; preferably, the temperature for the degumming treatment is 80-88 degrees Celsius, and the treatment time is 150-240 seconds; preferably, the etching rate during the degumming treatment is 0.1-0.48mg / cm³. 2 ; Preferably, in the neutralization treatment, a neutralizing solution is used. Preferably, the neutralizing solution includes the following components at the following concentrations: H2SO4: 20-50 ml / L, NU3002 (hydroxylamine sulfate): 50-100 ml / L. Preferably, the neutralization treatment temperature is 35-45 degrees Celsius, and the treatment time is 50-70 seconds. Preferably, in the well-draining process, a well-draining solution is used for treatment. Preferably, the well-draining solution includes the following components at the following concentrations: alkalinity: 0.13-0.17N. Preferably, sodium hydroxide is selected to adjust the alkalinity. Preferably, the temperature of the well-draining process is 50-60 degrees Celsius, and the treatment time is 50-70 seconds. Preferably, the micro-etching process uses a micro-etching solution, which preferably comprises the following components at the following concentrations: 50% H2SO4: 25-45 ml / L, SPS (sodium persulfate): 130-170 g / L. Preferably, the temperature for micro-etching is 25-30 degrees Celsius, and the processing time is 30-40 seconds. Preferably, in the pre-impregnation treatment, a pre-impregnation solution is used for treatment. Preferably, the pre-impregnation solution includes the following components at the following concentrations: PD3004: 30-70 ml / L. Preferably, the pre-impregnation treatment temperature is room temperature, and the treatment time is 10-20 seconds. Preferably, the activation treatment is carried out using an activation solution. Preferably, the activation solution has a Pd content of 60-120 ppm and a pH of 9-9.

5. Preferably, the activation treatment temperature is 45-55 degrees Celsius and the treatment time is 50-70 seconds. Preferably, the accelerated treatment uses a reducing solution, which preferably includes the following components at the following concentrations: boric acid: 10 g / L, 10% DMAB: 1% volume concentration. Preferably, the accelerated treatment temperature is 25-30 degrees Celsius, and the treatment time is 25-35 seconds.

9. The method for achieving signal isolation within a hole according to claim 1, characterized in that, After the pressing process, the method for achieving signal isolation within the hole further includes baking the pre-treated plate.

10. A printed circuit board, characterized in that, The method described in any one of claims 1 to 9 for achieving signal isolation within the hole based on anti-chemical copper plating ink and selective chemical copper plating process is used to prepare the sample.

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