Etching solution for AMB active metal brazing material etching process and horizontal line etching method thereof

Abstract

The invention provides an etching solution for an AMB active metal brazing material etching process and a horizontal line etching method thereof. The etching solution comprises the following components in parts by mass: 5.5-50 parts of a villiaumite compound; 0.5 to 3 parts of an acidity regulator; 5 to 35 parts of hydrogen peroxide; 0.05 to 5 parts of a copper protective agent; 0.03 to 3 parts of a surfactant; the etching liquid of the AMB active metal brazing material etching process is acidic. Fluorine ions of fluoride salt are complexed with Ag, and a villiaumite compound reacts with Ti to etch the brazing filler metal layer, so that the etching speed is rapidly increased, the etching time is shortened to be suitable for a horizontal line process, and then the length of a horizontal line is shortened; the copper protective agent forms a slow-release film on the surface of the copper surface, corrosion to the copper surface is reduced, etching liquid is prevented from permeating the side etching copper layer along the edge of the brazing filler metal layer, meanwhile, metal ions are reduced to catalyze decomposition of hydrogen peroxide, and then the use amount of the etching liquid is reduced.

Description

Technical Field

[0001] This disclosure relates to the technical field of circuit boards, and in particular to an etching solution for an AMB active metal solder etching process and a horizontal line etching method thereof. Background Technology

[0002] AMB circuit boards achieve chemical bonding between a ceramic substrate and a copper layer through the melting of active metal solder, thus forming a high-reliability circuit carrier. Current AMB circuit board manufacturing primarily employs vertical etching. In this method, the substrate is vertically suspended or placed in a basket during etching and cleaning processes. Transferring between processes, loading and unloading the baskets often relies heavily on manual operation or complex robotic arms, limiting production efficiency.

[0003] The horizontal AMB etching method for circuit boards allows for high-speed, high-volume production by continuously transporting the substrate horizontally through various processing tanks. However, existing etching solutions are slow in etching the solder layer, resulting in long horizontal etching production lines with large footprints, slow etching efficiency, and high production costs.

[0004] For example, the prior art document CN202110574541.5 discloses a patterned structure of a ceramic substrate and its manufacturing method. The etching solution contains hydrogen peroxide, ammonia, and the structure contains carboxyl groups and their salts, organic amines, surfactants and alcohols. The etching solution has a slow etching speed on the circuit board. The etching is carried out using a horizontal production line, which has a large equipment footprint and a slow etching process. Summary of the Invention

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide an etching solution and a horizontal line etching method for an AMB active metal solder etching process that increases etching speed, is suitable for horizontal line etching, and is highly efficient and cost-effective.

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

[0007] An etching solution for an AMB active metal solder etching process comprises the following components by weight:

[0008]

[0009]

[0010] The etching solution used in the AMB active metal solder etching process is acidic.

[0011] In one embodiment, the fluoride compound includes at least one of ammonium fluoride, ammonium hydrogen fluoride, sodium fluoride, and potassium fluoride.

[0012] In one embodiment, the copper protectant includes at least one of benzotriazole BTA, methylbenzotriazole TTA, 2-thiobenzothiazole MBT, amino alcohol borate, triethanolamine borate, and copper acetate.

[0013] In one embodiment, the acidity regulator includes at least one of cyclophosphamide, citric acid, oxalic acid, glycolic acid, acetic acid, and tartaric acid.

[0014] In one embodiment, the surfactant is selected from at least one of isomeric alcohol ethoxylate, EO / PO block polyether, ethoxylated fatty acid methyl ester, benzoquinone, and polyethylene glycol.

[0015] In one embodiment, the etching solution of the AMB active metal solder etching process further includes 0.05 to 0.3 parts of hydrogen peroxide stabilizer.

[0016] In one embodiment, it includes at least one of magnesium sulfate, aminoethanol phosphate, phosphate, diethylenetriaminepentaacetic acid, 8-hydroxyquinoline and 2-pyridinecarboxylic acid.

[0017] A horizontal line etching method using AMB active metal solder etching process, employing the etching solution of the AMB active metal solder etching process described in any of the above embodiments, includes the following steps:

[0018] The etching solution for the AMB active metal brazing alloy etching process is then injected into the etching tank.

[0019] Obtain a solder circuit board with etched copper surface lines;

[0020] The solder circuit board is transported to an etching tank via a horizontal transport line to etch the solder layer, thereby obtaining the etched AMB circuit board.

[0021] In one embodiment, obtaining a solder circuit board with etched copper surface lines includes the following steps:

[0022] An active metal solder is applied to the surface of a ceramic substrate, and copper foil is stacked on the active metal solder to obtain a laminated substrate.

[0023] The laminated substrate is placed in a vacuum furnace for heating and brazing to obtain a sintered substrate.

[0024] The sintered substrate is coated with an acrylic resin dry film;

[0025] The sintered substrate is developed and exposed;

[0026] The sintered substrate is subjected to copper etching to obtain a solder circuit substrate with etched copper surface lines.

[0027] In one embodiment, the etching tank etches the solder circuit board by circulating spraying.

[0028] Compared with the prior art, this disclosure has at least the following advantages:

[0029] The etching solution in the aforementioned AMB active metal solder etching process utilizes the complexation of fluoride ions with Ag and the reaction of fluoride compounds with Ti to etch the solder layer. This rapidly increases the etching speed of the solder layer, effectively shortening the length of horizontal lines while ensuring high line speed. This makes it suitable for horizontal line processes, significantly reducing the amount of etching solution used and achieving high efficiency and cost reduction in the AMB circuit board etching process. The acidity regulator maintains the acidity of the etching solution in the AMB active metal solder etching process, ensuring etching effect and avoiding damage to the dry film on the copper layer surface. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer. It also reduces the catalytic decomposition of hydrogen peroxide by metal ions, thereby reducing the amount of etching solution used. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart illustrating the steps of an AMB circuit board horizontal line etching method according to an embodiment;

[0032] Figure 2 These are the appearance images of the solder circuit board substrate after etching in Examples 1-2;

[0033] Figure 3 These are the appearance images of the solder circuit board substrates after etching in Examples 3-5;

[0034] Figure 4 This is a view of the solder circuit board after etching in Example 6;

[0035] Figure 5 These are the appearance images of the solder circuit board substrates after etching in Examples 7-10;

[0036] Figure 6 These are the appearance images of the solder circuit board substrate after etching in Examples 11-12;

[0037] Figure 7 The images show the effect of etching with the etching solution in Examples 11-12. Detailed Implementation

[0038] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this 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 complete understanding of the disclosure.

[0039] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments:

[0042] The etching solution for the AMB active metal solder etching process according to an embodiment of the present invention comprises the following components by mass:

[0043]

[0044] The etching solution used in the AMB active metal solder etching process is acidic.

[0045] In this embodiment, the active metal solder includes Ag, Cu, and Ti. When the active metal solder is heated with the ceramic substrate, Ti reacts with Si3N4 to form TiN / Ti5Si3, achieving chemical bonding and forming a solder layer on the ceramic substrate. The horizontal line process of the AMB circuit board requires etching of the solder layer. During the process of Ti and Si3N4 forming a chemical bond layer, Ti is consumed in the interface reaction, while Ag does not participate in the reaction. Ag is inert and only acts as a binder phase in the solder. The remaining Ag-Cu is pushed to the edges or gaps because it does not wet the ceramic. The concentration of hydrogen peroxide is 20%-35%. The etching solution of the AMB active metal solder etching process is acidic, making the etching solution compatible with the acrylic resin dry film system and avoiding damage to the acrylic resin dry film coated on the copper layer. The pH of the etching solution is 5-6, and the etching solution can be prepared by adding water.

[0046] The etching solution in the aforementioned AMB active metal solder etching process utilizes the complexation of fluoride ions with Ag and the reaction of fluoride compounds with Ti to etch the solder layer. This results in a better selective etching effect on silver, copper, titanium, and copper-titanium solders, leading to a rapid increase in the etching speed of the solder layer. While ensuring the line speed, this effectively shortens the length of horizontal lines, making it suitable for horizontal line processes and significantly reducing the amount of etching solution used. This achieves high efficiency and cost reduction in the AMB circuit board etching process. An acid regulator maintains the acidity of the etching solution in the AMB active metal solder etching process, ensuring etching effectiveness and preventing damage to the dry film on the copper layer surface. A copper protectant forms a slow-release film on the copper surface, reducing erosion and inhibiting the lateral etching of the copper layer along the edges of the solder layer. It also reduces the catalytic decomposition of hydrogen peroxide by metal ions, further reducing the amount of etching solution used.

[0047] In one embodiment, the fluoride compound includes at least one selected from ammonium fluoride, ammonium bifluoride, sodium fluoride, and potassium fluoride. In this embodiment, ammonium fluoride hydrolyzes to form a weakly acidic compound, resulting in mild etching, while ammonium bifluoride dissociates into HF. - The concentration of sodium fluoride is porous, it has a fast etching rate for Ti, and low corrosivity to ceramics.

[0048] Further, in one embodiment, the fluoride compound includes a mixture of ammonium fluoride and sodium fluoride, or a mixture of atomized ammonium fluoride and potassium fluoride, or a mixture of ammonium hydrogen fluoride and potassium fluoride, or a mixture of ammonium hydrogen fluoride and sodium fluoride, or a mixture of ammonium hydrogen fluoride and ammonium fluoride. In this embodiment, the ion synergy and regulation of the composite fluoride can improve etching efficiency and protect the ceramic substrate. The mixture of ammonium fluoride and sodium fluoride provides gentle etching, reducing the risk of damage to the solder layer and the ceramic substrate; the mixture of ammonium hydrogen fluoride and sodium fluoride increases the migration rate of F- through Na+, and NH4+...4+ Complexing Ag increases the etching rate; the mixture of ammonium bifluoride and potassium fluoride, and the mixture of atomized ammonium and potassium fluoride, inhibit the decomposition of NH4HF2 with K+, thereby improving temperature stability; the mixture of ammonium bifluoride and ammonium fluoride enhances Ag dissolution through a bisammonium system, improving the elimination effect on Ag edge residues.

[0049] In one embodiment, the copper protectant includes at least one selected from benzotriazole BTA, methylbenzotriazole TTA, amino alcohol borate, triethanolamine borate, and copper acetate. In this embodiment, the copper protectant selectively adsorbs or forms a film on the copper surface, achieving protection by blocking the contact of the etching solution, while also being compatible with a fluoride compound system; wherein, the adsorbent protectant benzotriazole BTA reacts with Cu... + A chain polymer is formed and vertically adsorbed onto the copper surface. Methylbenzotriazole (TTA) enhances hydrophobicity through methyl substitution, forming a dense monolayer. Copper acetate, a reactive protective agent, is deposited on the copper surface through reaction and inhibits etching through anodic passivation. Complexing protective agents include aminohydroborates and triethanolamine borates. Aminohydroborates form a network film through film-forming reaction with CuO, while triethanolamine borate forms a complex film through film-forming reaction, thereby inhibiting etching.

[0050] In one embodiment, the acid modifier includes at least one selected from aminocyclic acid, citric acid, oxalic acid, glycolic acid, acetic acid, and tartaric acid. In this embodiment, when the acid modifier is too acidic, it damages the bonding layer and corrodes the ceramic substrate. The acid modifier needs to maintain an optimal pH to ensure fluoride ion activity. The acid modifier can also chelate with metal ions to prevent redeposition. Specifically, aminocyclic acid is used to maintain the pH of the etching solution, and aminocyclic acid reacts with Fe... 3+ Ion chelation is suitable for etching solutions containing iron impurities; when citric acid is used to maintain the pH of the etching solution, citric acid reacts with Cu. 2+ Ion chelation prevents copper ion redeposition, thus reducing the erosion of the copper surface by the etching solution; oxalic acid is used to maintain the pH of the etching solution, and oxalic acid can react with Ti... 4+ Chelation reduces titanium residue; when glycolic acid is used to maintain the pH of the etching solution, it can react with Al. 3+ Chelation is suitable for AlN ceramic substrates; acetic acid is only used to adjust pH and has little effect on the ceramic substrate; when tartaric acid is used to maintain the pH of the etching solution, tartaric acid reacts with Cu... 2+ Ion chelation prevents copper ion deposition.

[0051] In one embodiment, the surfactant includes at least one of isomeric alcohol ethoxylates, EO / PO block polyethers, ethoxylated fatty acid methyl esters, mixtures of fatty alcohol alkoxy compounds and benzoquinone, and polyethylene glycol. In this embodiment, the surfactant can reduce surface tension and enhance the penetration of the etching solution; furthermore, isomeric alcohol ethoxylates and EO / PO block polyethers have high compatibility with fluorinated compounds.

[0052] In one embodiment, the etching solution for the AMB active metal solder etching process further includes 0.02 to 5 parts of hydrogen peroxide stabilizer. It is understood that hydrogen peroxide is prone to decomposition during oxidation; therefore, a hydrogen peroxide stabilizer is necessary. The hydrogen peroxide stabilizer selectively chelates metal ions to prevent the ineffective decomposition of H2O2. Through precise chelation control, the long-term stability and process repeatability of the AMB etching solution are ensured.

[0053] Further, the hydrogen peroxide stabilizer includes at least one of magnesium sulfate, aminoethanol phosphate, phosphate, diethylenetriaminepentaacetic acid, 8-hydroxyquinoline, and 2-pyridinecarboxylic acid. In this embodiment, the hydrogen peroxide stabilizer chelates metal ions, preventing the decomposition of H2O2, avoiding precipitation or complexation failure, and is compatible with acidic etching environments, thereby ensuring the long-term stability and process repeatability of the AMB etching solution. Specifically, magnesium sulfate stabilizes hydrogen peroxide molecules through complexation; aminoethanol phosphate and Ti... 4+ Cu 2+ and Fe 3+ The formation of stable chelates prevents metal ions from catalyzing the decomposition of hydrogen peroxide. Phosphates form soluble chelates with metal ions such as Fe3+ and Mn2+ that undergo catalytic decomposition, reducing their activity. Diethylenetriaminepentaacetic acid reacts with Ti... 4+ Cu 2+ and Fe 3+ It forms a highly stable cyclic chelate, effectively blocking the catalytic decomposition of hydrogen peroxide by metal ions; 8-hydroxyquinoline can react with Cu... 2+ and Fe 3+ It forms stable chelates, reducing its catalytic activity; 2-pyridinecarboxylic acid can form chelates with metal ions, and its acidic functional groups can regulate the pH of the solution, inhibiting the decomposition of hydrogen peroxide.

[0054] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium fluoride: 10-40 parts; sodium fluoride: 1-2 parts; aminocyclic acid: 0.5-3 parts; hydrogen peroxide: 5-35 parts; benzotriazole (BTA): 0.05-2 parts; isomeric alcohol ethoxylate: 0.05-2 parts; magnesium sulfate: 0.05-2 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0055] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium fluoride: 10-40 parts; potassium fluoride: 5-10 parts; citric acid: 0.5-1 part; hydrogen peroxide: 5-35 parts; methylbenzotriazole (TTA): 0.3-1.0 parts; EO / PO block polyether: 0.5-1.5 parts; aminoethanol phosphoric acid: 0.1-0.3 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0056] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium bifluoride: 10-40 parts; potassium fluoride: 5-10 parts; oxalic acid: 0.3-1 part; hydrogen peroxide: 5-35 parts; mercaptobenzothiazole-2-thiobenzothiazole MBT: 0.05-0.1 parts; ethoxylated fatty acid methyl ester (FMEE): 0.03-0.1 parts; phosphate: 1-5 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0057] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium bifluoride: 5-40 parts; sodium fluoride: 0.5-1 part; glycolic acid: 0.5-1.2 parts; hydrogen peroxide: 5-35 parts; aminohydroboroate: 1-5 parts; benzoquinone: 0.2-0.5 parts; DTPA (diethylenetriaminepentaacetic acid): 1-3 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0058] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium bifluoride: 5-25 parts; ammonium fluoride: 0.5-1 part; acetic acid: 0.5-2 parts; hydrogen peroxide: 5-35 parts; triethanolamine borate: 0.2-0.5 parts; polyethylene glycol (PEG-1200): 0.5-1 part; 8-hydroxyquinoline: 0.05-0.1 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0059] In one embodiment, the etching solution for the AMB active metal solder etching process comprises the following components by weight: ammonium bifluoride: 5-25 parts; ammonium fluoride: 5-15 parts; tartaric acid: 0.5-1.2 parts; hydrogen peroxide: 5-35 parts; copper acetate: 0.1-0.3 parts; polyethylene glycol (PEG-800): 0.1-0.5 parts; 2-pyridinecarboxylic acid: 0.02-0.1 parts; the etching solution for the AMB active metal solder etching process is acidic. In this embodiment, the etching solution for the AMB active metal solder etching process exhibits good selective etching effect on silver, copper, titanium, and copper-titanium solders. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer.

[0060] like Figure 1 As shown, this application also provides a horizontal line etching method using an AMB active metal solder etching process, employing the etching solution of the AMB active metal solder etching process described in any of the above embodiments, and including the following steps:

[0061] S101 is used to prepare the etching solution for the etching process of AMB active metal brazing filler metal and then injects it into the etching tank.

[0062] S103 Obtains a solder circuit board with etched copper surface lines;

[0063] S105 transports the solder circuit board to the etching tank via a horizontal transport line to etch the solder layer, thereby obtaining the etched AMB circuit board.

[0064] In this embodiment, fluoride compounds, acidity adjusters, hydrogen peroxide, copper protectants, surfactants, and water are mixed to obtain the etching solution for the AMB active metal solder etching process. The etching solution for the AMB active metal solder etching process can be prepared by adding water. The solder circuit board includes a copper layer, a solder layer, and a ceramic substrate layer. An acrylic resin dry film is coated on the surface of the copper layer. After developing and exposing the solder circuit board, the copper layer area to be etched is exposed. The exposed copper layer area can be selectively removed by immersion in a copper chloride and hydrochloric acid system, thereby exposing the solder layer area to be etched. The solder layer to be etched is removed by the etching solution for the AMB active metal solder etching process. The fluoride compounds in the etching solution etch the Ti and Ag in the solder layer by reacting with the fluoride compounds, thereby obtaining the etched AMB circuit board.

[0065] The aforementioned horizontal line etching method of the AMB active metal solder etching process utilizes the fluoride compounds in the etching solution to achieve rapid etching of Ti and Ag, and exhibits good selective etching effects on silver, copper, titanium, and copper-titanium solders. This method protects the copper surface while maintaining a fast etching speed for the solder, effectively shortening the length of the horizontal line to suit horizontal line processes. This significantly reduces the amount of etching solution used, achieving high efficiency and cost reduction in the AMB circuit board etching process. Furthermore, the copper protectant in the etching solution provides excellent copper protection, reducing the catalytic decomposition of hydrogen peroxide due to copper etching, extending the service life of the etching solution, and minimizing the need for replenishment during continuous horizontal line production.

[0066] In one embodiment, after copper plating with solder on a ceramic substrate, a solder circuit board is obtained, including the following steps:

[0067] An active metal solder is applied to the surface of a ceramic substrate, and copper foil is stacked on the active metal solder to obtain a laminated substrate.

[0068] The laminated substrate is placed in a vacuum furnace for heating and brazing to obtain a sintered substrate.

[0069] The sintered substrate is coated with an acrylic resin dry film;

[0070] The sintered substrate is developed and exposed;

[0071] The sintered substrate is subjected to copper etching to obtain a solder circuit substrate with etched copper surface lines.

[0072] In this embodiment, the ceramic substrate is moved via a horizontal transport line. The ceramic substrate is cleaned to remove surface residues. Then, active metal solder paste is applied to the ceramic substrate and laminated with copper foil to form a laminated substrate with a uniform solder layer. The laminated substrate is heated in a vacuum furnace at 800℃-900℃. Ti in the active metal solder paste reacts with Si3N4 to form TiN / Ti5Si3, achieving chemical bonding. This allows the active metal solder to form a solder layer on the ceramic substrate. The ceramic substrate, solder layer, and copper layer of the sintered substrate are then integrated. The sintered substrate is then degreased and cleaned to ensure a clean surface for the resulting solder circuit board, facilitating subsequent copper etching.

[0073] Further, in one embodiment, after copper etching is performed on the solder circuit board to obtain a solder circuit board with etched copper surface lines, and before the solder circuit board is transported to an etching tank via a horizontal transport line for etching to obtain the etched AMB circuit board, the following steps are included:

[0074] The dry film layer of acrylic resin is removed using a stripping solution;

[0075] Alternatively, after transporting the solder circuit board to an etching tank via a horizontal transport line for etching to obtain the etched AMB circuit board, the following steps are included:

[0076] The dry film layer of acrylic resin is removed using a stripping solution.

[0077] In this embodiment, the etching solution contains a copper protectant, which forms a protective layer on the copper layer surface, thereby inhibiting the etching of the copper layer by H2O2 in the etching solution. This allows the etching solution to selectively etch the solder layer on the solder circuit substrate after the dry film has been removed. Therefore, the film can be removed before etching the solder layer, ensuring uniform contact between the etching solution and the exposed solder layer of the copper layer, thereby improving the etching uniformity. Furthermore, the etching solution has a high corrosion inhibition rate on the copper layer, resulting in less etching on the copper circuit surface and avoiding residual film removal solution affecting the consumption of subsequent etching solutions. When film removal is performed after etching the solder layer, the acrylic resin has a good protective effect on the copper surface during the etching process, and the etching solution etches the edges of the solder layer more uniformly. The film removal solution only needs to treat the dry film dissolution products.

[0078] Further, in one embodiment, the active metal solder includes active metal solder paste or active metal solder sheet. In this embodiment, the active metal solder paste is composed of silver, copper, and titanium, and the active metal solder sheet is stacked on a ceramic substrate. During heating, Ti is located at the bottom of the solder layer and reacts and bonds with the ceramic substrate, while Ag floats on the upper layer of the solder layer. The active metal solder sheet is composed of copper and titanium, and the Ti content in the active metal solder sheet is greater than the titanium content in the active metal solder paste.

[0079] In one embodiment, the active metal solder paste comprises 60%-80% Ag, 30%-50% Cu, and 3%-5% Ti by mass. This active metal solder paste is easily applied to complex shapes, narrow slots, or non-planar joints, and can fill minute gaps, making it suitable for workpieces with complex structures. The high content of Ag and Cu provides excellent electrical and thermal conductivity. The active metal solder sheet comprises 70%-80% Cu and 20%-30% Ti by mass. The high melting points of Cu and Ti in the active metal solder sheet result in high high-temperature strength of the bond.

[0080] Furthermore, in one embodiment, the etching time of the etching solution in the AMB active metal solder etching process is 10-40 minutes. In this embodiment, the etching time of a traditional etching solution containing hydrogen peroxide, ammonia, carboxyl groups and their salts, organic amines, surfactants, and alcohols is 40-150 minutes. The etching time of the etching solution using the AMB active metal solder etching process is only 10-40 minutes. This allows the etching solution of the AMB active metal solder etching process to achieve a fast etching speed for the solder while protecting the copper surface, requiring only about 30% of the time of traditional solutions. This effectively shortens the length of horizontal lines while ensuring line speed, significantly reducing the amount of solvent used and increasing the etching rate, thereby achieving the effect of increasing efficiency and reducing costs.

[0081] Further, in one embodiment, the horizontal transport line moves the solder circuit board at a speed of 5 m / min-20 m / min. In this embodiment, when the etching time using conventional horizontal spray etching solution is 40 min-150 min, the horizontal transport line moves the solder circuit board at a speed of 1 m / min-3 m / min. However, when using the AMB active metal solder etching process, the etching time is 10 min-40 min, and the horizontal transport line moves the solder circuit board at a speed of 5 m / min-20 m / min. It is understood that the shorter the etching time, the faster the horizontal transport line moves the solder circuit board. With the AMB process, the etching time is significantly shorter than the conventional process. At the same production rate, the moving speed is significantly increased. While ensuring production rate, the etching line length is shortened, effectively reducing the length of the horizontal line and significantly reducing the amount of etching solution used, thus achieving high efficiency and cost reduction in the AMB circuit board etching process.

[0082] In one embodiment, the etching tank etches the solder circuit board using a circulating spray system. In this embodiment, the circulating spraying of the solder circuit board ensures uniform spraying of the etching solution, resulting in consistent etching levels across different parts of the board. This effectively improves etching precision and quality, reduces circuit defects caused by uneven etching, increases penetration into the pores of the solder circuit board, enhances the effectiveness of the etching solution, and further shortens the etching time. Specifically, the spray pressure of the etching tank via the spray device is 0.5-1.5 kg / cm². 3 The etching solution is circulated and sprayed onto the solder circuit board. The etching time of the etching tank is 8 min-30 min for etching the solder circuit board by circulating spray.

[0083] Compared with the prior art, this disclosure has at least the following advantages:

[0084] The etching solution in the aforementioned AMB active metal solder etching process utilizes the complexation of fluoride ions with Ag and the reaction of fluoride compounds with Ti to etch the solder layer. This rapidly increases the etching speed of the solder layer, effectively shortening the length of horizontal lines while ensuring high line speed. This makes it suitable for horizontal line processes, significantly reducing the amount of etching solution used and achieving high efficiency and cost reduction in the AMB circuit board etching process. The acidity regulator maintains the acidity of the etching solution in the AMB active metal solder etching process, ensuring etching effect and avoiding damage to the dry film on the copper layer surface. The copper protectant forms a slow-release film on the copper surface, reducing erosion of the copper surface and inhibiting the lateral etching of the copper layer along the edge of the solder layer. It also reduces the catalytic decomposition of hydrogen peroxide by metal ions, thereby reducing the amount of etching solution used.

[0085] The following are some specific examples. When %, it refers to a percentage by weight. It should be noted that the following examples do not exhaustively list all possible scenarios, and unless otherwise specified, the materials used in the examples are commercially available.

[0086] Example 1

[0087] Etching solution for AMB active metal brazing solder etching process: Mix 20 kg of ammonium fluoride, 1 kg of sodium fluoride, 0.5 kg of aminocyclic acid, 30 kg of 30% hydrogen peroxide, 0.1 kg of benzotriazole BTA, 1 kg of isomeric alcohol ethoxylate and 0.1 kg of magnesium sulfate to obtain etching solution, and put the etching solution into etching tank.

[0088] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0089] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0090] Example 2

[0091] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of citric acid, 30 kg of 30% hydrogen peroxide, 0.5 kg of methylbenzotriazole TTA, 0.5 kg of EO / PO block polyether and 0.1 kg of aminoethanol phosphoric acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0092] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0093] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0094] Example 3

[0095] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of oxalic acid, 30 kg of 30% hydrogen peroxide, 0.1 kg of methylbenzotriazole (TTA), 0.1 kg of 2-thiobenzothiazole (MBT) and 0.05 kg of ethoxylated fatty acid methyl ester (FMEE) are mixed and stirred to obtain the etching solution, which is then placed in an etching tank;

[0096] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0097] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0098] Example 4

[0099] Etching solution for AMB active metal solder etching process: 20 kg of ammonium bifluoride, 0.5 kg of sodium fluoride, 0.5 kg of glycolic acid, 30 kg of 30% hydrogen peroxide, 1 kg of amino alcohol borate, 0.2 kg of fatty alcohol alkoxy compound, 0.2 kg of benzoquinone and 1 kg of DTPA (diethylenetriaminepentaacetic acid) are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0100] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0101] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0102] Example 5

[0103] Etching solution for AMB active metal solder etching process: 20 kg of ammonium bifluoride, 5 kg of ammonium fluoride, 0.5 kg of tartaric acid, 30 kg of 30% hydrogen peroxide, 0.1 kg of copper acetate, 0.1 kg of polyethylene glycol (PEG-800) and 0.02 kg of 2-pyridinecarboxylic acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0104] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0105] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0106] Example 6

[0107] Etching solution for AMB active metal solder etching process: 20 kg of ammonium bifluoride, 0.5 kg of ammonium fluoride, 0.5 kg of acetic acid, 30 kg of 30% hydrogen peroxide, 1 kg of triethanolamine borate, 0.5 kg of polyethylene glycol (PEG-1200) and 0.1 kg of 8-hydroxyquinoline are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0108] An active metal solder sheet is applied to the surface of a ceramic substrate, and copper foil is stacked on the active metal solder sheet to obtain a multilayer substrate. The multilayer substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the solder circuit substrate. The solder circuit substrate is then developed and exposed. Finally, copper etching is performed on the solder circuit substrate to obtain a solder circuit substrate with etched copper surface lines.

[0109] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0110] Example 7

[0111] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of citric acid, 20 kg of 30% hydrogen peroxide, 0.5 kg of methylbenzotriazole TTA, 0.5 kg of EO / PO block polyether and 0.1 kg of aminoethanol phosphoric acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0112] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0113] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0114] Example 8

[0115] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of citric acid, 30 kg of 30% hydrogen peroxide, 0.5 kg of methylbenzotriazole TTA, 0.5 kg of EO / PO block polyether and 0.1 kg of aminoethanol phosphoric acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0116] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0117] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0118] Example 9

[0119] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of citric acid, 20 kg of 30% hydrogen peroxide, 0.5 kg of methylbenzotriazole TTA, 0.5 kg of EO / PO block polyether and 0.1 kg of aminoethanol phosphoric acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0120] An active metal solder sheet is applied to the surface of a ceramic substrate, and copper foil is stacked on the metal solder sheet to obtain a multilayer substrate. The multilayer substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the solder circuit substrate. The solder circuit substrate is then developed and exposed. Finally, copper etching is performed on the solder circuit substrate to obtain a solder circuit substrate with etched copper surface lines.

[0121] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0122] Example 10

[0123] Etching solution for AMB active metal solder etching process: 20 kg of ammonium fluoride, 5 kg of potassium fluoride, 0.5 kg of citric acid, 30 kg of 30% hydrogen peroxide, 0.5 kg of methylbenzotriazole TTA, 0.5 kg of EO / PO block polyether and 0.1 kg of aminoethanol phosphoric acid are mixed and stirred to obtain etching solution, which is then placed in etching tank;

[0124] An active metal solder sheet is applied to the surface of a ceramic substrate, and copper foil is stacked on the metal solder sheet to obtain a multilayer substrate. The multilayer substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the solder circuit substrate. The solder circuit substrate is then developed and exposed. Finally, copper etching is performed on the solder circuit substrate to obtain a solder circuit substrate with etched copper surface lines.

[0125] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0126] Example 11

[0127] Etching solution for AMB active metal brazing solder etching process: Mix 20 kg of ammonium fluoride, 1 kg of sodium fluoride, 0.5 kg of aminocyclic acid, 30 kg of 27.5% hydrogen peroxide, 0.1 kg of benzotriazole BTA, 1 kg of isomeric alcohol ethoxylate and 0.1 kg of magnesium sulfate to obtain etching solution, and put the etching solution into etching tank.

[0128] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0129] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0130] Example 12

[0131] Etching solution for AMB active metal brazing solder etching process: 20 kg of ammonium fluoride, 1 kg of sodium fluoride, 0.5 kg of aminocyclic acid, 30 kg of 27.5% hydrogen peroxide, 0.1 kg of benzotriazole BTA and 1 kg of isomeric alcohol ethoxylate are mixed and stirred to obtain etching solution, and the etching solution is put into etching tank.

[0132] Active metal solder paste is coated onto the surface of a ceramic substrate, and copper foil is laminated onto the active metal solder paste to obtain a laminated substrate. The laminated substrate is then placed in a vacuum furnace for brazing and sintering to obtain a sintered substrate. An acrylic resin dry film is coated onto the brazing circuit substrate. The brazing circuit substrate is then developed and exposed. Finally, copper etching is performed on the brazing circuit substrate to obtain a brazing circuit substrate with etched copper surface lines.

[0133] The solder circuit board is transported to an etching tank for etching to obtain the etched AMB circuit board.

[0134] Table 1 Etching tests of etching solutions in Examples 1-6

[0135]

[0136] Table 2 Test results of Examples 7-10

[0137]

[0138] Table 3 Test results of Examples 11 and 12

[0139]

[0140] It should be noted that in Examples 1-5, active metal solder paste was used to prepare the solder circuit board, but the proportions of Ag, Cu, and Ti in the active metal solder paste were different. Specifically, Example 5 was prepared using active metal solder pads, and Example 6 had the highest Ti content. Examples 7 and 8 were prepared using the same active metal solder paste. In Examples 9 and 10, the proportions of Ag, Cu, and Ti in the solder circuit boards prepared using active metal solder paste were the same. In Examples 11 and 12, the proportions of Ag, Cu, and Ti in the solder circuit boards prepared using active metal solder pads were the same.

[0141] Test Procedure: When testing the corrosion inhibition rate of oxygen-free copper, oxygen-free copper sheets of the same area and thickness were selected. The weight of the oxygen-free copper sheets was measured first. The oxygen-free copper sheets were then immersed in the etching solution for 3 or 4 hours, removed and dried. The etching rate and corrosion inhibition rate of copper were calculated based on the amount of etching of the oxygen-free copper sheets. When testing the retention rate of H2O2, the H2O2 before the reaction was titrated, and then titrated again 15 hours after etching. The retention rate of H2O2 in the etching solution was calculated.

[0142] from Figures 2-4 As can be seen from Table 1, all of Examples 1-5 completed the etching of the solder layer within 15 minutes, indicating that the etching solutions of Examples 1-5 have a faster etching speed and better etching effect on active metal solder paste containing Ag, Cu and Ti.

[0143] Example 6 uses a circuit board made with active metal solder pads. The solder layer mainly contains Cu and Ti. The Ti content in the active metal solder pads is higher than that in active metal solder paste. After etching for 10 minutes, the circuit board surface in Example 5 had a relatively large amount of residual Ti metal. After etching for 22 minutes, there was no residue on the surface of the circuit board in Example 5. This indicates that the etching solution in Example 5 can effectively remove residual Ti, and the etching solution in Example 5 has a good etching effect on the solder layer. The Ti content in the solder layer affects the etching rate of the etching solution.

[0144] From Table 2 and Figure 5It can be seen that the etching solutions of Examples 7-10 have good etching effects on active metal solder sheets and active metal solder paste; Example 10 has a higher hydrogen peroxide content than Example 9, and the increased hydrogen peroxide content is beneficial to accelerating the etching speed; After soaking oxygen-free copper sheets for 3 hours, the corrosion inhibition rate of oxygen-free copper sheets in Examples 7-10 is relatively high, indicating that the etching solutions of Examples 7-10 cause less corrosion to the copper surface;

[0145] From Table 3, Figure 6 and Figure 7 It can be seen that after etching the oxygen-free copper sheet with the etching solution of Example 11 without adding copper protectant, the increase of Cu ions caused the etching solution of Example 11 to turn blue, and the amount of oxygen-free copper etched was relatively large. The copper corrosion inhibition rate of Example 12 was relatively high. This indicates that the etching solution with added copper protectant has less etching on the copper surface. The copper protectant forms a slow-release film on the copper surface, reducing the erosion on the copper surface and inhibiting the etchant from penetrating and laterally etching the copper layer along the edge of the solder layer. At the same time, it reduces the metal ion catalytic decomposition of hydrogen peroxide, thereby reducing the amount of etching solution used.

[0146] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An etching solution for an AMB active metal solder etching process, characterized in that, Includes the following mass components: Fluoride salts: 5.5-50 parts; Acidity regulator: 0.5-3 parts; Hydrogen peroxide: 5-35 parts; Copper protectant: 0.05-5 parts; Surfactant: 0.03-3 parts; The etching solution used in the AMB active metal solder etching process is acidic.

2. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, The fluoride salt compound includes at least one of ammonium fluoride, ammonium hydrogen fluoride, sodium fluoride, and potassium fluoride.

3. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, The copper protectant includes at least one of benzotriazole BTA, methylbenzotriazole TTA, 2-thiobenzothiazole MBT, amino alcohol borate, triethanolamine borate, and copper acetate.

4. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, The acidity regulator includes at least one of cyclophosphamide, citric acid, oxalic acid, glycolic acid, acetic acid, and tartaric acid.

5. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, The surfactant is selected from at least one of isomeric alcohol ethoxylate, EO / PO block polyether, ethoxylated fatty acid methyl ester, benzoquinone, and polyethylene glycol.

6. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, The etching solution in the AMB active metal solder etching process also includes 0.05 to 0.3 parts of hydrogen peroxide stabilizer.

7. The etching solution for the AMB active metal solder etching process according to claim 1, characterized in that, It includes at least one of magnesium sulfate, aminoethanol phosphate, phosphate, diethylenetriaminepentaacetic acid, 8-hydroxyquinoline and 2-pyridinecarboxylic acid.

8. A horizontal line etching method using AMB active metal solder etching process, characterized in that, Etching using the etching solution of the AMB active metal solder etching process described in claims 1-7 includes the following steps: The etching solution for the AMB active metal brazing alloy etching process is then injected into the etching tank. Obtain a solder circuit board with etched copper surface lines; The solder circuit board is transported to an etching tank via a horizontal transport line to etch the solder layer, thereby obtaining the etched AMB circuit board.

9. The horizontal line etching method of the AMB active metal solder etching process according to claim 8, characterized in that, Obtaining a solder circuit board with etched copper surface lines includes the following steps: An active metal solder is applied to the surface of a ceramic substrate, and copper foil is stacked on the active metal solder to obtain a laminated substrate. The laminated substrate is placed in a vacuum furnace for heating and brazing to obtain a sintered substrate. The sintered substrate is coated with an acrylic resin dry film; The sintered substrate is developed and exposed; The sintered substrate is subjected to copper etching to obtain a solder circuit substrate with etched copper surface lines.

10. The horizontal line etching method of the AMB active metal solder etching process according to claim 8, characterized in that, The etching cylinder etches the solder circuit board through a circulating spray.

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