阅读说明：本技术 一种用于5g信号板化学沉锡的药水 (Liquid medicine for chemical tin precipitation of 5G signal plate ) 是由 杜腾辉 谭文灵 陈太平 于 2021-10-09 设计创作，主要内容包括：本发明公开了一种用于5G信号板化学沉锡的药水,属于化学沉锡技术领域,所述药水组合物包括沉锡用A剂和预处理剂B剂。本发明中,氯化铈和纳米铋微粒能够粘附在亚锡离子表面空位、位错露头和晶界,能使晶粒表面能降低,从而提高锡离子置换反应,保证镀层的成型速率增加,氯化铈和纳米铋能够降低溶剂电阻率,在通过置换反应同步吸附在铜基表面后,能够提高导电性能,同时在沉锡处理前PCB板预浸入B剂内预处理,使得非离子表面活性剂后能够将APG、槲皮素和硫脲均匀分散吸附在铜基表面,使得铜基表面具有良好的润湿性,在置换反应时,锡离子扩散系数减少,沉积过程受到抑制,结晶细致和均匀,提高导电强度和耐用寿命。(The invention discloses a liquid medicine for chemical tin precipitation of a 5G signal plate, belonging to the technical field of chemical tin precipitation. In the invention, cerium chloride and nano bismuth particles can be adhered to a stannous ion surface vacancy, a dislocation outcrop and a crystal boundary, and the surface energy of a crystal grain can be reduced, so that a stannum ion replacement reaction is improved, the forming rate of a coating is increased, the solvent resistivity can be reduced by cerium chloride and nano bismuth, the conductivity can be improved after the cerium chloride and the nano bismuth are synchronously adsorbed on a copper-based surface through the replacement reaction, and meanwhile, a PCB (printed circuit board) is pre-soaked in a B agent for pretreatment before the stannum deposition treatment, so that APG, quercetin and thiourea can be uniformly dispersed and adsorbed on the copper-based surface after a non-ionic surfactant, the copper-based surface has good wettability, the diffusion coefficient of stannum ions is reduced during the replacement reaction, the deposition process is inhibited, the crystallization is fine and uniform, the conductivity is improved, and the service life is prolonged.)

1. The liquid medicine for chemical tin precipitation of the 5G signal plate is characterized by comprising an A agent for tin precipitation and a B agent for a pretreatment agent, wherein the A agent comprises the following components in percentage by mass: 5-12% of stannous compound, 18-26% of reducing agent, 18-26% of complexing agent, 1-5% of addition auxiliary agent, 8-10% of reducing agent and the balance of pure water, wherein the agent B comprises the following components in parts by weight: 2-6% of penetrating agent, 1-5% of modifying agent and the balance of pure water.

2. The liquid medicine for chemical tin deposition of the 5G signal plate is characterized in that the stannous compound is one or a combination of stannous sulfate, stannous chloride and stannic sulfonate.

3. The liquid medicine for 5G signal plate chemical immersion tin is characterized in that the reducing agent is sodium hypophosphite and the complexing agent is a citric acid reagent.

4. The liquid medicine for chemical tin deposition of the 5G signal plate is characterized in that the addition auxiliary agent is a modified cerium chloride solution, and the cerium chloride solution is modified and loaded with nano bismuth by an impregnation method.

5. The liquid medicine for chemical tin deposition of a 5G signal plate, according to claim 1, is characterized in that the modifier comprises quercetin and thiourea, and the weight ratio is 2: 3.

6. The chemical liquid for chemical tin deposition of the 5G signal plate is characterized in that the penetrating agent comprises a nonionic surfactant APG, and the mass percent of the nonionic surfactant is 1%.

7. The chemical tin deposition reagent for the 5G signal board as claimed in claim 1, wherein the reagent composition further comprises ammonia water as a pH regulator, and the pH value of the regulated reagent composition is 8-10.

Technical Field

The invention belongs to the technical field of chemical tin precipitation, and particularly relates to a liquid medicine for chemical tin precipitation of a 5G signal plate.

Background

The PCB tin deposition process is a new green and environment-friendly process which is specially designed for facilitating SMT and chip packaging and is used for depositing a tin metal coating on a copper surface in a chemical mode, replaces a Pb-Sn alloy coating, is widely applied to electronic products, hardware, ornaments and the like, and is widely used because a 5G signal board can realize more precise tin plating treatment of a circuit board through chemical tin deposition;

the 5G signal is a signal transmitted by utilizing a fifth generation mobile communication technology, is a new generation broadband mobile communication technology with the characteristics of high speed, low time delay and large connection, and has higher physical performance for a 5G signal plate because the 5G signal transmission needs the characteristics of high power, low time delay and large connection, and a tin-plated layer of the traditional signal plate lacks certain matching capability for the tin-plated layer.

In recent years, tin plating has been widely used as a solderable plating in the industries of electronic components and semiconductor packaging using copper and copper alloy as a base, and chinese patent publication No. CN110106535B discloses a neutral tin plating additive, which is characterized in that the tin plating additive comprises the following raw materials by weight: 20-30% of complexing agent, 1-3% of wetting agent, 1-5% of surfactant, 10-20% of pH regulator and the balance of water. The scheme avoids dangers and pollution caused by acid additives in the prior art, and can keep stable performance at different temperatures, wherein Chinese patent publication No. CN104746057B discloses a chemical tin plating solution and a preparation method thereof, the chemical tin plating solution contains tin salt, a complexing agent, a reducing agent and an accelerator, wherein the reducing agent is titanium chloride, and the accelerator contains a sulfonic acid accelerator; the sulfonic acid accelerator is at least one selected from A, B, C, wherein A is dodecyl seleno sulfonate, B is a mixture of dodecyl sulfonate and seleno sulfonate, and C is a mixture of dodecyl sulfonate and seleno sulfate. According to the chemical tin plating solution provided by the scheme, the sulfonic acid promoter is added into the chemical tin plating solution of the titanium chloride reducing agent, so that the activity and stability of the plating solution can be effectively improved, but in actual use, the tin plating agents lack the inhibiting effect on the agglomeration phenomenon in a plated film, and the thickness of a deposited tin layer cannot meet the process requirement of a signal board.

Disclosure of Invention

The invention aims to: the chemical tin deposition liquid medicine for the 5G signal plate is provided for solving the problem that tin deposition layer thickness cannot meet the process requirement of the signal plate due to the fact that tin plating agents lack the inhibiting effect on the agglomeration phenomenon in a plated film.

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

the liquid medicine composition comprises an A agent for tin precipitation and a pretreatment agent B agent, wherein the A agent comprises the following components in percentage by mass: 5-12% of stannous compound, 18-26% of reducing agent, 18-26% of complexing agent, 1-5% of addition auxiliary agent, 8-10% of reducing agent and the balance of pure water, wherein the agent B comprises the following components in parts by weight: 2-6% of penetrating agent, 1-5% of modifying agent and the balance of pure water.

As a further description of the above technical solution:

the stannous compound is one or a combination of stannous sulfate, stannous chloride and stannic sulfonate.

As a further description of the above technical solution:

the reducing agent is sodium hypophosphite, and the complexing agent is a citric acid reagent.

As a further description of the above technical solution:

the addition auxiliary agent is a modified cerium chloride solution, and the cerium chloride solution is modified and loaded with nano bismuth by an immersion method.

As a further description of the above technical solution:

the modifier comprises quercetin and thiourea, and the weight ratio is 2: 3.

As a further description of the above technical solution:

the penetrating agent comprises a nonionic surfactant APG, and the mass percent of the nonionic surfactant is 1%.

As a further description of the above technical solution:

the liquid medicine composition also comprises a pH regulator ammonia water, and the pH value of the liquid medicine composition after regulation is 8-10.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

in the invention, cerium chloride particle solution and loaded nano bismuth are added in a gathering way by adding an auxiliary agent, cerium chloride and nano bismuth particles can be adhered to vacancy, dislocation outcrop and grain boundary on the surface of stannous ions, so that the surface energy of crystal grains can be reduced, thus improving the displacement reaction of stannum ions, ensuring that the forming rate of a coating is increased, cerium chloride and nano bismuth can reduce the resistivity of a solvent, and after being synchronously adsorbed on the surface of a copper base through the displacement reaction, the conductivity can be improved, so that the deposition rate of a tin precipitation liquid medicine is improved, meanwhile, a PCB (printed circuit board) is pre-soaked in a B agent for pretreatment before tin precipitation treatment, APG, quercetin and thiourea can be uniformly dispersed and adsorbed on the surface of the copper base after a non-ionic surfactant, so that the surface of the copper base has good wettability, the diffusion coefficient of stannum ions is reduced during the displacement reaction, the deposition process is inhibited, and the crystallization is fine and uniform, the conductive strength is improved and the service life is prolonged.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

the invention provides a technical scheme that: the liquid medicine composition comprises an A agent for tin precipitation and a pretreatment agent B agent, wherein the A agent comprises the following components in percentage by mass: 5% of stannous compound, 18% of reducing agent, 18% of complexing agent, 1% of addition auxiliary agent, 8% of reducing agent and the balance of pure water, wherein the agent B comprises the following components in parts by weight: the disinfectant comprises a penetrant, a modifier and the balance of pure water, wherein the stannous compound is stannous sulfate, the reducing agent is sodium hypophosphite, the complexing agent is a citric acid reagent, the additive is a modified cerium chloride solution, the cerium chloride solution is modified by an impregnation method and loaded with nano bismuth, the modifier comprises quercetin and thiourea, the weight ratio is 2:3, the penetrant comprises a nonionic surfactant APG, the mass percentage of the nonionic surfactant is 1%, the liquid medicine composition further comprises a pH regulator ammonia water, and the pH value of the adjusted liquid medicine composition is 8;

wherein, the tin deposition method comprises the steps of pretreating the PCB, coating a B agent pretreating agent on the tin deposition position on the surface of the PCB, and the mixed A agent is put into the mixed A agent, the citric acid and the thiourea form a stable complex with the plating base surface CU2 to make the potential of copper shift negatively, the purpose of tin precipitation is achieved, the stannous ions in the A agent are replaced on the copper base surface of the PCB through a replacement reaction, meanwhile, the modified additive, penetrant and modifier are loaded on the surface of the tin coating through complexation to realize compact modification treatment of the coating, the nonionic surfactant can effectively change the surface wettability of the plating base, and the oxide on the surface of the copper base can be removed before the immersion plating, the relative bonding strength after the tin ion immersion plating is improved, the phenomena that the base surface is whitish and the solder mask is removed at the position of a window sharp corner caused by the overlarge side corrosion of the window edge of the copper surface in the processing process are reduced, and the accuracy of the immersion plating process is improved.

Example 2:

the invention provides a technical scheme that: the liquid medicine composition comprises an A agent for tin precipitation and a pretreatment agent B agent, wherein the A agent comprises the following components in percentage by mass: 8% of stannous compound, 23% of reducing agent, 22% of complexing agent, 3% of addition auxiliary agent, 9% of reducing agent and the balance of pure water, wherein the agent B comprises the following components in parts by weight: the disinfectant comprises a penetrant 4%, a modifier 3% and the balance of pure water, wherein the stannous compound is stannous chloride, the reducing agent is sodium hypophosphite, the complexing agent is a citric acid reagent, the addition auxiliary agent is a modified cerium chloride solution, the cerium chloride solution is modified by an impregnation method and loaded with nano bismuth, the modifier comprises quercetin and thiourea, the weight ratio is 2:3, the penetrant comprises a nonionic surfactant APG, the mass percentage of the nonionic surfactant is 1%, the liquid medicine composition further comprises a pH regulator ammonia water, and the pH value of the adjusted liquid medicine composition is 8.

Example 3:

the invention provides a technical scheme that: the liquid medicine composition comprises an A agent for tin precipitation and a pretreatment agent B agent, wherein the A agent comprises the following components in percentage by mass: 12% of stannous compound, 26% of reducing agent, 26% of complexing agent, 5% of addition auxiliary agent, 10% of reducing agent and the balance of pure water, wherein the agent B comprises the following components in parts by weight: the disinfectant comprises 6% of a penetrating agent, 5% of a modifying agent and the balance of pure water, wherein the stannous compound is tin sulfonate, the reducing agent is sodium hypophosphite, the complexing agent is a citric acid reagent, the addition auxiliary agent is a modified cerium chloride solution, the cerium chloride solution is modified by an impregnation method and loaded with nano bismuth, the modifying agent comprises quercetin and thiourea, the weight ratio is 2:3, the penetrating agent comprises a nonionic surfactant APG, the mass percentage of the nonionic surfactant is 1%, the liquid medicine composition further comprises a pH regulator ammonia water, and the pH value of the adjusted liquid medicine composition is 10.

Test example:

taking five samples of each group of samples prepared in the embodiment as sample sheets, purchasing the sample sheets after tin deposition of a PCB (printed circuit board) in the traditional process as a comparative example, analyzing the phase of a chemical tin coating by using an X-ray diffractometer, measuring and judging the thickness of the deposited tin, testing and judging the corrosion resistance of the samples by using a polarization curve in a sodium chloride solution with the mass fraction of 3.5%, and testing the surface resistivity to obtain the following table:

as can be seen from the above table, the corrosion potential decreases with the increase of the thickness of the tin layer, which indicates that the higher the thickness is, the stronger the corrosion resistance is, and the surface uniformity, the density and the resistivity are all well represented when the thickness of the tin layer is 1.32um, which is a preferred embodiment of the present invention, and phase judgment shows that tin grains of the stannous compound are the smallest when the addition amount is 5%, the arrangement is loose, and the tin grains in the plating layer are moderate in size and the arrangement is the most compact when the addition amount is 8%; % 12 is the largest and the most loose tin grains in the coating.

Chemical substances:

stannous chloride chemical formula SnCl2, an inorganic compound, is white crystalline powder;

sodium hypophosphite, an inorganic compound, a strong reducing agent, has the chemical formula NaH2PO2, and is a colorless crystal or white powder with pearl luster. Salty taste and deliquescence. Heating strongly, decomposing to release phosphine and igniting in air immediately, mixing with strong oxidant to cause explosion, dissolving in glycerol and hot ethanol easily, dissolving in water and cold ethanol, slightly dissolving in anhydrous ethanol, and not dissolving in diethyl ether;

the complexing agent is sodium citrate, and citric acid is a complexing agent and is easy to form a complex with metal ions with high valence;

cerium chloride, otherwise known as cerium (III) chloride, is an anhydrous cerium chloride or a polyhydrated compound of cerium chloride that irritates the eyes, respiratory system, and skin. The catalyst is used in industries such as petroleum catalysts, automobile exhaust catalysts, intermediate compounds and the like;

nano bismuth: bismuth is an environment-friendly brittle metallic electrical material, has high resistivity and strong diamagnetism, and can be applied to semiconductor raw materials;

and (3) quercetin: is flavonol compounds with wide distribution in plant boundary and multiple biological activities, and has a chemical formula of C15H10O₇；

Thiourea: is an organic sulfur-containing compound with a molecular formula of CH4N2S, white and glossy crystal, bitter taste, and density of 1.41g/cm³The melting point is 176-178 ℃. Raw materials for producing drugs, dyes, resins, molding powders, etc., vulcanization accelerators for rubbers, flotation agents for metal minerals, etc.;

APG: the alkyl glycoside (APG for short) is a non-ionic surfactant, is a novel non-ionic surfactant directly synthesized by natural glucose and natural fatty alcohol in one step, has the characteristics of common non-ionic and anionic surfactants, and has high surface activity, good ecological safety and compatibility.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.