A copper reduction additive and copper reduction process for HDI boards

Abstract

The application relates to a copper-reducing additive for HDI plates and a copper-reducing process, wherein the copper-reducing additive comprises sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator, antioxidant and water; the pinhole inhibitor comprises a halide salt; and the accelerator comprises an amine compound and / or an alcohol compound. The copper-reducing process comprises preparing an etching solution by using the copper-reducing additive, and then spraying and etching a filled hole plate by using the etching solution to obtain a copper-reduced filled hole plate. The copper-reducing additive provided by the application can maintain the stability of the etching rate in a wide range of chloride ion concentration and a high upper limit of copper ion concentration, and can inhibit the generation of pinholes at the blind hole and the copper surface after copper reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of copper reduction technology, and in particular to a copper reduction additive for HDI boards and a copper reduction process. Background Art

[0002] As electronic products develop towards becoming thinner, lighter, and smaller, printed circuit boards (PCBs) are also being driven towards higher density. Compared to the subtractive manufacturing process used in conventional PCBs (Printed Circuit Boards), High Density Interconnect (HDI) technology offers significant advantages in achieving smaller apertures, finer line widths and spacing, reducing PCB area, increasing component density, and improving radio frequency interference. Currently, HDI technology is widely used in high-end PCB manufacturing.

[0003] The manufacturing process of HDI involves a via-filling electroplating process. The copper surface is usually thick after via-filling. In order not to affect the yield of subsequent processes, it needs to be thinned. Currently, most commercial copper-reducing etching solutions are sulfuric acid-hydrogen peroxide systems. This etching solution has the following defects: (1) The sulfuric acid-hydrogen peroxide etching solution system is sensitive to chloride ions, and the introduction of chloride ions needs to be strictly controlled during the preparation and use of the etching solution; (2) The upper limit of the copper ion concentration in the etching solution is low, and the bath solution needs to be frequently replaced, which reduces production capacity and increases wastewater discharge; (3) Pinhole defects are prone to appear in the copper-reducing via-filling board of the sulfuric acid-hydrogen peroxide system.

[0004] In the copper reduction process, the principle of pinhole formation is mainly attributed to the following two points: (1) During the hole filling electroplating process, the growth rate of the grains is difficult to maintain consistency, resulting in different grain sizes. During etching, the etching rate of small grains is faster, and after the small grains are completely corroded, the large grains have not yet been etched, thus forming pinholes. Although the depth of such pinholes is generally shallow, they affect the transmission of signals. (2) During the electroplating process, organic impurities are deposited in the local plating layer, hindering the growth of normal crystals, forming a narrow tunnel-shaped small crystal area in the direction of crystal growth, that is, abnormal crystallization. The copper atoms in the abnormal crystallization are very active, and during etching, they form a galvanic effect with local impurities, and the copper acts as an anode and dissolves rapidly, forming pinholes. Such pinholes are usually deep, and in severe cases, they can penetrate the entire copper plating layer, causing a short circuit, seriously affecting the product yield and subsequent processes.

[0005] Therefore, it is of great significance to provide a copper-reducing additive that is beneficial to maintaining a stable etching rate and avoiding the occurrence of pinholes. Summary of the Invention

[0006] In response to the above problems, the present invention aims to provide a copper-reducing additive and copper-reducing process for HDI boards. Compared with the prior art, the copper-reducing additive and copper-reducing process provided by the present invention can maintain a stable etching rate within a wider chloride ion range and at higher copper ion concentrations, reduce the requirements of the etching solution for water quality, and avoid or reduce the occurrence of pinholes in blind holes and copper surfaces of filled hole boards after copper reduction.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a copper-reducing additive for HDI boards, the copper-reducing additive comprising: sulfuric acid, a hydrogen peroxide stabilizer, a pinhole inhibitor, an accelerator, an antioxidant, and water;

[0009] The pinhole inhibitor includes a halide salt;

[0010] The accelerator includes an amine compound and / or an alcohol compound.

[0011] In the copper-reducing additive provided by the present invention, sulfuric acid promotes the dissolution of the pinhole inhibitor and accelerator. Hydrogen peroxide stabilizer molecules contain organic atoms such as N, O, and S, which can form hydrogen bonds with H atoms in hydrogen peroxide molecules, reducing the activity of [HO·2] and thereby reducing the self-decomposition rate of hydrogen peroxide. The pinhole inhibitor, which includes a halide salt, functions in two main ways: first, to address the problem of uneven copper grains, a cuprous halide passivation film is formed on the surface of small grains with faster etching rates, suppressing the etching rate of small grains and thereby improving the consistency of etching rates across copper grains of different sizes, significantly suppressing pinhole formation. Second, to address the problem of abnormal crystallization, the copper atoms in the abnormal crystallization sites react with impurities during etching, causing the copper atoms in the abnormal crystallization sites to rapidly dissolve as anodes. The cuprous halide passivation film produced by the present invention shifts the potential in this area to the positive side, thereby suppressing the galvanic effect and reducing the copper corrosion rate, thereby inhibiting pinhole formation. The control accelerator includes an amine compound and / or an alcohol compound. The function of the amine compound is as follows: the amine compound can complex with the cuprous halide, thereby breaking up and dissolving the cuprous halide passivation film formed during the etching process, preventing the long-term presence of the cuprous halide passivation film from severely inhibiting corrosion, thereby increasing the etching rate; the amine compound itself can complex with copper ions, preventing excessive copper ion concentration from catalyzing the decomposition of hydrogen peroxide and causing a decrease in etching rate; the introduction of the alcohol compound can reduce the surface tension of the etching solution, increase the diffusion rate of the effective components to the copper surface, and accelerate the formation and dissolution of the cuprous halide passivation film; and the alcohol compound can improve the stability of the hydrogen peroxide, thereby increasing the effective concentration of hydrogen peroxide and thus increasing the etching rate. The antioxidant functions to improve the uniformity of the board surface after etching and prevent the formation of oxides on the copper surface after etching. The copper-reducing additive provided by the present invention is a synergistic combination of sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator, antioxidant, and water, which can improve the stability of the etching rate and avoid or reduce the formation of pinholes.

[0012] Preferably, the copper-reducing additive includes 35-140 g / L of sulfuric acid, for example, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 85 g / L, 95 g / L, 105 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L or 140 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] Preferably, the copper-reducing additive includes 10-50 g / L of hydrogen peroxide stabilizer, for example, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L or 50 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] Preferably, the copper-reducing additive includes 5-20 g / L of pinhole inhibitor, for example, 5 g / L, 6 g / L, 8 g / L, 10 g / L, 12 g / L, 14 g / L, 16 g / L, 18 g / L or 20 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] Preferably, the copper-reducing additive includes 150-500 g / L of accelerator, for example, 150 g / L, 180 g / L, 200 g / L, 220 g / L, 240 g / L, 260 g / L, 280 g / L, 300 g / L, 320 g / L, 340 g / L, 360 g / L, 380 g / L, 400 g / L, 420 g / L, 440 g / L, 460 g / L, 480 g / L or 500 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, the copper-reducing additive includes 40-100 g / L of antioxidant, for example, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L or 100 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] Preferably, the balance of the copper-reducing additive is water.

[0018] In the present invention, it is preferred to control the addition amounts of sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator, antioxidant and water within a specific range, which can further exert the synergistic effect of each group, help improve the stability of the etching rate, and avoid or reduce the generation of pinholes.

[0019] Preferably, the hydrogen peroxide stabilizer includes a sulfonic acid compound.

[0020] Preferably, the concentration of the sulfonic acid compound in the copper-reducing additive is 20-40 g / L, for example, 20 g / L, 22 g / L, 25 g / L, 28 g / L, 30 g / L, 32 g / L, 35 g / L, 38 g / L or 40 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the sulfonic acid compound includes any one or a combination of at least two of taurine, 3-thio-isothioureapropylsulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 6-amino-1-naphthalenesulfonic acid, quinoline-8-sulfonic acid, N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid, N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid, 3-(N-morpholinyl)-2-hydroxypropanesulfonic acid, 3-amino-4-methoxybenzenesulfonic acid, (S)-2-amino-3-phenylpropane-1-sulfonic acid, piperazine-1,4-diethanesulfonic acid monosodium salt, sodium naphthalene-1-sulfonate, anthraquinone-2-sulfonic acid sodium salt or sodium isophenylpropanesulfonate.

[0022] Preferably, the halide salt comprises a chloride salt and / or a bromide salt, preferably a chloride salt.

[0023] Preferably, the chloride salt comprises a chloride salt ionic liquid and / or a chloride salt solid, preferably a combination of a chloride salt ionic liquid and a chloride salt solid.

[0024] Preferably, the mass ratio of the chloride ionic liquid to the chloride solid in the copper-reducing additive is (1-3):1, for example, 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] In the present invention, the pinhole inhibitor is preferably a combination of a chloride ionic liquid and a chloride solid. The two act synergistically to form a CuCl passivation film. On the one hand, the CuCl passivation film is generated on the surface of small grains, thereby improving the consistency of etching rates for grains of different sizes and inhibiting pinhole formation. On the other hand, pinhole formation is inhibited by suppressing the galvanic cell effect. On the other hand, the active N component in the ionic liquid is adsorbed on the copper surface, further improving the isotropy of etching rates for copper grains of different sizes, causing the regional potential of abnormal copper grains to further shift positively, thereby further inhibiting the formation of pinholes.

[0026] Preferably, the concentration of the chloride ionic liquid in the copper-reducing additive is 3-15 g / L, for example, 3 g / L, 4 g / L, 6 g / L, 8 g / L, 10 g / L, 12 g / L, 14 g / L or 15 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] Preferably, the concentration of chloride solid in the copper-reducing additive is 2-5 g / L, for example, 2 g / L, 3 g / L, 4 g / L or 5 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the chloride ionic liquid includes 1-butylpyridinium chloride, 1-(2-oxopropyl)pyridinium chloride, 1-butyl-4-methylpyridinium chloride, 4-methyl-1-((2-methylthiazol-4-yl)methyl)pyridinium-1-chloride, 1-ethylpyridinium chloride, 1-(2-amino-2-oxoethyl)pyridinium-1-chloride, 1-hexylpyridinium chloride, 1-(2-hydrazino-2-oxoethyl)pyridinium chloride, -1-ammonium chloride, 3-ethyl-1-methyl-1H-imidazole-3-chloride, 1-allyl-3-vinylimidazolium chloride, 1-methyl-3-propyl-1H-imidazole-3-ammonium chloride, 2,3-dimethyl-1-octyl-1H-imidazole-3-ammonium chloride, 1-methyl-1-octylpyrrolidine-1-ammonium chloride or 1-ethyl-1-methylpyrrolidine-1-ammonium chloride, or a combination of at least two thereof.

[0029] Preferably, the chloride salt solid comprises sodium chloride.

[0030] Preferably, the accelerator comprises an amine compound and an alcohol compound.

[0031] In the present invention, the accelerator is preferably controlled to be a combination of an amine compound and an alcohol compound, which can exert a synergistic effect of the amine compound and the alcohol compound and further enhance the effect of accelerating etching.

[0032] Preferably, the mass ratio of the amine compound to the alcohol compound in the copper-reducing additive is (0.5-4):1, for example, it can be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the concentration of the amine compound in the copper-reducing additive is 100-400 g / L, for example, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L or 400 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, the concentration of the alcohol compound in the copper-reducing additive is 50-400 g / L, for example, 50 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L or 400 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] Preferably, the amine compound includes any one or a combination of at least two of 3,5-dimethoxyaniline, 4-n-butylaniline, biuret, 2-((2-aminoethyl)amino)ethanol, N,N-dibutyl-1,3-propylenediamine, N'N-bis(3-aminopropyl)methylamine, N-acetylethylenediamine, 3,4-diaminobenzamidine, 2-aminopyrimidine, isocytosine, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole or 1,3-benzothiazol-5-amine.

[0036] Preferably, the alcohol compound includes any one or a combination of at least two of sorbitol, 3-ethoxy-1-propanol, cyclohexanol, isobutanol, isooctyl alcohol, 4-amino-1-butanol, 2-amino-2-methyl-1,3-propanediol, 1,4-butynediol or 2,5-dimethyl-2,5-hexanediol.

[0037] Preferably, the mass ratio of the pinhole inhibitor to the accelerator in the copper-reducing additive is 1:(10-25), for example, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, 1:22 or 1:25, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] In the present invention, the mass ratio of the pinhole inhibitor and the accelerator is preferably controlled within a specific range, which can promote the mutual cooperation of the pinhole inhibitor and the accelerator, so that the formation rate of the cuprous halide passivation film is slightly higher than or close to the dissolution rate of the cuprous halide, so that the formation and dissolution of the cuprous halide are in dynamic equilibrium, and both the pinhole inhibition effect and a high etching rate level are taken into account: on the one hand, it is avoided that the ratio of the pinhole inhibitor and the accelerator is too high, resulting in the formation rate of the cuprous halide passivation film being greater than the dissolution rate, resulting in a low etching rate and reduced production efficiency; on the other hand, it is avoided that the ratio of the pinhole inhibitor and the accelerator is too low, resulting in the formation rate of the cuprous halide passivation film being less than the dissolution rate, thereby reducing the pinhole inhibition effect.

[0039] Preferably, the antioxidant comprises any one or a combination of at least two of ascorbic acid, sodium gluconate, glutaric acid, pimelic acid, sodium nitrilotriacetate, 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid or N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid.

[0040] In a second aspect, the present invention provides a copper reduction process, wherein the copper reduction process uses the copper reduction additive described in the first aspect of the present invention;

[0041] The copper reduction process comprises the following steps:

[0042] (1) dissolving sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator and antioxidant in 50% of the formula amount of water, and then adding the remaining formula amount of water and stirring to obtain a copper-reducing additive;

[0043] (2) preparing an etching solution using the copper-reducing additive obtained in step (1), sulfuric acid, hydrogen peroxide, and water, and heating the mixture;

[0044] (3) The etching solution obtained in step (2) is used to spray-etch the hole-filled plate to obtain a hole-filled plate with reduced copper.

[0045] In the present invention, the general operation method in step (1) is: 50% of the formula amount of water is pre-added to the reactor, and then sulfuric acid, hydrogen peroxide stabilizer, accelerator, antioxidant and pinhole inhibitor are added in sequence, stirred until dissolved, and then the remaining formula amount of water is added and stirred to obtain the copper-reducing additive.

[0046] In the present invention, the general method of preparation in step (2) is: first add half the amount of water to the etching tank, then add sulfuric acid and copper-reducing additives in sequence, and after sufficient circulation and dissolution, add hydrogen peroxide and add water to the liquid level line, and then heat to obtain the etching solution.

[0047] Preferably, the amount of sulfuric acid added to the etching solution is 140-220 g / L, for example, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 210 g / L or 220 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] Preferably, the amount of the copper-reducing additive added to the etching solution is 40-60 mL / L, for example, 40 mL / L, 42 mL / L, 45 mL / L, 48 mL / L, 50 mL / L, 52 mL / L, 58 mL / L or 60 mL / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] Preferably, copper sulfate pentahydrate is also added to the etching solution.

[0050] In the present invention, copper sulfate pentahydrate is usually added after the copper-reducing additive.

[0051] Preferably, the amount of copper sulfate pentahydrate added to the etching solution is 20-220 g / L, for example, 20 g / L, 40 g / L, 80 g / L, 60 g / L, 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L or 200 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0052] Preferably, the amount of hydrogen peroxide added to the etching solution is 32-48 g / L, for example, 32 g / L, 34 g / L, 36 g / L, 38 g / L, 40 g / L, 42 g / L, 44 g / L, 46 g / L, or 48 g / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. The specific amount added can be increased or decreased depending on the etching rate. In the present invention, the mass fraction of hydrogen peroxide used in the preparation of the etching solution is 35%, which is equivalent to an amount of hydrogen peroxide added to the etching solution of 32-48 g / L.

[0053] Preferably, the spray etching in step (3) is performed in an etching tank.

[0054] Preferably, the upper spray pressure of the spray etching is 2.0-2.3 kg / cm 2 , for example, it can be 2.0kg / cm 2 , 2.1kg / cm 2 , 2.2kg / cm 2 or 2.3kg / cm 2 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, the spray pressure of the spray etching is 1.1-1.4 kg / cm 2 , for example, it can be 1.1 kg / cm 2 , 1.2kg / cm 2 , 1.3kg / cm 2 or 1.4kg / cm 2 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0056] Preferably, the temperature of the spray etching is 36-40°C, for example, it can be 36°C, 37°C, 38°C, 39°C or 40°C, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable. The specific temperature can be appropriately increased or decreased according to the etching rate.

[0057] Preferably, the etching amount of each of the hole-filling plates is 5-15 μm, for example, it can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable. The specific copper reduction amount is increased or decreased depending on the copper thickness.

[0058] Corresponding to the above etching amount, the etching time of each of the filled hole plates is 90-330s, for example, it can be 90s, 100s, 120s, 150s, 180s, 200s, 220s, 250s, 280s, 300s or 330s, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable. The specific etching time is appropriately increased or shortened according to actual requirements such as etching rate and copper reduction.

[0059] In the present invention, under continuous production conditions, during the spray etching process of step (3), it is necessary to add supplementary etching solution to the etching tank by automatic adding equipment, and the automatic addition amount of supplementary etching solution is calculated using the following formula:

[0060] Q=17.92×E / C L ;

[0061] Wherein, Q represents the automatic addition amount of the supplementary etching solution, i.e., the amount of the supplementary etching solution added to the etching tank; E represents the copper reduction amount, i.e., the etching amount, which is generally 5-15 μm in the present invention; C L The upper limit of copper ion concentration in the etching solution is set to 55 g / L in the present invention. Therefore, the amount of etching solution added is calculated to be 1.63-4.89 L / m 2 Plate, for example, can be 1.63L / m 2 board, 1.95L / m 2 board, 2.28m 2 Board, 2.61m 2 board, 2.93m 2 board, 3.26m 2 board, 3.58m 2 board, 3.91m 2 Board 4.24m 2 、4.56m 2 or 4.89m 2 Board, but not limited to the listed values, other values ​​not listed within the numerical range are also applicable, and the specific automatic addition amount is determined according to the copper reduction demand.

[0062] In the present invention, "1.63L / m 2 For example, the board is "under continuous etching conditions, each time 1m 2 For the filled hole plate, the automatic adding equipment will extract 1.63L of additional etching solution into the etching tank, thereby maintaining the stability of the etching solution composition. The adding process is the process of the filled hole plate entering and exiting the etching tank.

[0063] Preferably, the supplementary etching solution is prepared with a copper-reducing additive, sulfuric acid and hydrogen peroxide.

[0064] Preferably, the amount of the copper-reducing additive added to the supplementary etching solution is 59-79 mL / L, for example, it can be 59 mL / L, 61 mL / L, 65 mL / L, 67 mL / L, 71 mL / L, 74 mL / L, 77 mL / L or 79 mL / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable. The specific amount added is determined according to the amount of the copper-reducing additive added when the etching solution is prepared in the etching tank and the set upper limit of the copper ion concentration.

[0065] Preferably, the amount of sulfuric acid added to the supplementary etching solution is 230-300 g / L, for example, it can be 230 g / L, 240 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L or 300 g / L, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable. The specific amount added is determined according to the amount of sulfuric acid added when the etching solution is prepared in the etching tank and the upper limit of the copper ion concentration is set.

[0066] Preferably, the amount of hydrogen peroxide added to the supplemental etching solution is 61-77 g / L, for example, 61 g / L, 65 g / L, 69 g / L, 73 g / L, or 77 g / L, but is not limited to the listed values. Other values ​​within the numerical range not listed are also applicable. The specific amount added is determined by the amount of hydrogen peroxide added when preparing the etching solution in the etching tank and the set upper limit of the copper ion concentration. In the present invention, the mass fraction of hydrogen peroxide used in the preparation of the supplemental etching solution is 35%, which is equivalent to an amount of hydrogen peroxide added to the supplemental etching solution of 61-77 g / L.

[0067] In the present invention, the amount of each component added to the supplementary etching solution is calculated using the following formula:

[0068] C 补 (sulfuric acid) = 1.57 × C L +C 硫酸 ;Unit: g / L;

[0069] C 补 (hydrogen peroxide) = 0.535C L +C 过氧化氢 ;Unit: g / L;

[0070] C 补 (Copper reduction additive) = 0.338C L +C 减铜添加剂 ;Unit: mL / L;

[0071] In the above formula, C L Set an upper limit for the copper ion concentration in the etching solution; C 补is the amount of the relevant component added to the supplemental etching solution (such as sulfuric acid, hydrogen peroxide, or a copper-reducing additive); and C is the amount of the relevant component added to the etching solution when it is prepared in the etching tank. For example, if the upper limit of the copper ion concentration is set to 55 g / L, the amounts of sulfuric acid, hydrogen peroxide, and copper-reducing additive added to the etching solution when it is prepared in the etching tank are 143 g / L, 40 g / L, and 50 mL / L, respectively. Using the above formula, the amounts of sulfuric acid, hydrogen peroxide, and copper-reducing additive added to the supplemental etching solution are 229.4 g / L, 69.4 g / L, and 68.6 mL / L, respectively.

[0072] As a preferred technical solution of the present invention, the copper reduction process includes the following steps:

[0073] (1) dissolving sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator and antioxidant in 50% of the formula amount of water, and then adding the remaining formula amount of water and stirring to obtain a copper-reducing additive;

[0074] (2) preparing an etching solution using the copper-reducing additive obtained in step (1), sulfuric acid, copper sulfate pentahydrate, hydrogen peroxide, and water, and heating the mixture;

[0075] The amount of sulfuric acid added to the etching solution is 140-220 g / L, the amount of copper-reducing additive added is 40-60 mL / L, the amount of copper sulfate pentahydrate added is 20-220 g / L, and the amount of hydrogen peroxide added is 32-48 g / L;

[0076] (3) The etching solution obtained in step (2) is sprayed at a pressure of 2.0-2.3 kg / cm 2 , the lower spray pressure is 1.1-1.4kg / cm 2 , spray etching the filled hole plate at a temperature of 36-40° C., the etching amount of each filled hole plate is 5-15 μm, and the etching time of each filled hole plate is 90-330 s;

[0077] When carried out under continuous conditions, during the spray etching process, an automatic adding device is used to add supplementary etching solution to the etching tank, and the amount of sulfuric acid added to the supplementary etching solution is 230-300 g / L, the amount of hydrogen peroxide added is 61-77 g / L, and the amount of copper-reducing additive added is 59-79 mL / L.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] (1) The copper-reducing additive and copper-reducing process provided by the present invention can maintain a stable etching rate within a wide range of chlorine conditions, thereby reducing the requirements for water quality in the preparation of the copper-reducing additive, and tap water can be used for preparation.

[0080] (2) The copper-reducing additive and copper-reducing process provided by the present invention maintain a stable etching rate at a relatively high copper ion concentration (the upper limit of the copper ion concentration reaches above 55 g / L).

[0081] (3) The copper-reducing additive and copper-reducing process provided by the present invention can effectively avoid and reduce the formation of pinholes in the blind holes and copper surfaces of the hole-filling plate, thereby improving the yield rate of the blind holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 This is an etching rate fluctuation diagram of the etching solution described in Example 1 of the present invention under continuous production conditions;

[0083] Figure 2 This is a blind hole yield fluctuation diagram of the etching solution described in Example 1 of the present invention under continuous production conditions;

[0084] Figure 3 is a microscope image of the blind hole obtained in Example 1 of the present invention;

[0085] Figure 4 is a microscope image of the blind hole obtained in Example 6 of the present invention;

[0086] Figure 5 1 is a microscope image of the blind hole obtained in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0087] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0088] Example 1

[0089] This embodiment provides a copper-reducing additive for HDI boards, the copper-reducing additive comprising:

[0090]

[0091] The hydrogen peroxide stabilizer is N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid; the pinhole inhibitor is a mixture of an ionic liquid and a chloride solid in a mass ratio of 1:1, that is, the concentration of 1-butylpyridinium chloride is 5 g / L, and the concentration of sodium chloride is 5 g / L; the accelerator is a mixture of an amine compound and an alcohol compound in a mass ratio of 2:3, that is, the concentration of N,N-bis(3-aminopropyl)methylamine is 80 g / L, the concentration of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole is 20 g / L, and the concentration of isooctyl alcohol is 150 g / L; the mass ratio of the pinhole inhibitor to the accelerator is 1:25; and the antioxidant is ascorbic acid.

[0092] This embodiment further provides a copper reduction process using the above copper reduction additive, the copper reduction process comprising the following steps:

[0093] (1) 50% of the formula amount of water is pre-added to a reactor, and then sulfuric acid, hydrogen peroxide stabilizer, accelerator, antioxidant and pinhole inhibitor are added in order according to the formula amount, stirred until dissolved, and then the remaining formula amount of water is added and stirred to obtain a copper-reducing additive;

[0094] (2) First, add water to the etching tank, then sulfuric acid and copper-reducing additives. After sufficient circulation and dissolution, add 35% hydrogen peroxide and add water to the liquid level line. Control the amount of sulfuric acid added to 143g / L, the amount of copper-reducing additive added to 50mL / L, and the amount of hydrogen peroxide added to 40g / L;

[0095] (3) The etching solution obtained in step (2) is sprayed at a pressure of 2.2 kg / cm 2 , the lower spray pressure is 1.3kg / cm 2 The filled hole board was spray etched at a temperature of 38°C for 84 seconds to obtain a filled hole board with reduced copper.

[0096] Example 2

[0097] This embodiment provides a copper-reducing additive for HDI boards, the copper-reducing additive comprising:

[0098]

[0099] The hydrogen peroxide stabilizer is 3-sulfur-isothioureapropylsulfonic acid; the pinhole inhibitor is a mixture of an ionic liquid and a chloride solid in a mass ratio of 3:1, that is, the concentration of 1-(2-oxypropyl)pyridine chloride is 9 g / L, and the concentration of sodium chloride is 3 g / L; the accelerator is a mixture of an amine compound and an alcohol compound in a mass ratio of 4:1, that is, the concentration of N,N-dibutyl-1,3-propylenediamine is 200 g / L, the concentration of 3-amino-1,2,4-triazole is 40 g / L, and the concentration of 3-ethoxy-1-propanol is 60 g / L; the mass ratio of the pinhole inhibitor to the accelerator is 1:15; and the antioxidant is sodium gluconate.

[0100] This embodiment further provides a copper reduction process using the above copper reduction additive, the copper reduction process comprising the following steps:

[0101] (1) 50% of the formula amount of water is pre-added to a reactor, and then sulfuric acid, hydrogen peroxide stabilizer, accelerator, antioxidant and pinhole inhibitor are added in order according to the formula amount, stirred until dissolved, and then the remaining formula amount of water is added and stirred to obtain a copper-reducing additive;

[0102] (2) first add water to the etching tank, then add mass fraction sulfuric acid, copper reducing additive and copper sulfate pentahydrate in sequence, and after sufficient circulation and dissolution, add 35% mass fraction hydrogen peroxide and add water to the liquid level line, controlling the addition amount of sulfuric acid to 143g / L, the addition amount of copper reducing additive to 40mL / L, the addition amount of copper sulfate pentahydrate to 20g / L, and the addition amount of hydrogen peroxide to 45g / L;

[0103] (3) The etching solution obtained in step (2) is sprayed at a pressure of 2.0 kg / cm 2 , the lower spray pressure is 1.4kg / cm 2 The filled hole board was spray etched at a temperature of 40°C for 76 seconds to obtain a filled hole board with reduced copper.

[0104] Example 3

[0105] This embodiment provides a copper-reducing additive for HDI boards, the copper-reducing additive comprising:

[0106]

[0107]

[0108] The hydrogen peroxide stabilizer is sodium naphthalene-1-sulfonate; the pinhole inhibitor is a mixture of an ionic liquid and a chloride solid in a mass ratio of 2:1, that is, the concentration of 1-(2-hydrazino-2-oxoethyl)pyridine-1-ammonium chloride is 8 g / L, and the concentration of sodium chloride is 4 g / L; the accelerator is a mixture of an amine compound and an alcohol compound in a mass ratio of 2:1, that is, the concentration of 2-aminopyrimidine is 60 g / L, the concentration of N-acetylethylenediamine is 40 g / L, and the concentration of 1,4-butynediol is 50 g / L; the mass ratio of the pinhole inhibitor to the accelerator is 1:10; and the antioxidant is glutaric acid.

[0109] This embodiment further provides a copper reduction process using the above copper reduction additive, the copper reduction process comprising the following steps:

[0110] (1) 50% of the formula amount of water is pre-added to a reactor, and then sulfuric acid, hydrogen peroxide stabilizer, accelerator, antioxidant and pinhole inhibitor are added in order according to the formula amount, stirred until dissolved, and then the remaining formula amount of water is added and stirred to obtain a copper-reducing additive;

[0111] (2) First, water is added to the etching tank, and then sulfuric acid, copper reducing additive and copper sulfate pentahydrate are added in sequence. After sufficient circulation and dissolution, hydrogen peroxide with a mass fraction of 35% is added and water is added to the liquid level line. The amount of sulfuric acid added is controlled to be 220 mL / L, the amount of copper reducing additive added is 60 mL / L, the amount of copper sulfate pentahydrate added is 20 g / L, and the amount of hydrogen peroxide added is 40 g / L;

[0112] (3) The etching solution obtained in step (2) is sprayed at a pressure of 2.3 kg / cm 2 , the lower spray pressure is 1.1kg / cm 2 The filled hole board was spray etched at a temperature of 39°C for 80 seconds to obtain a filled hole board with reduced copper.

[0113] Example 4

[0114] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the accelerator contains 48 g / L of N,N-bis(3-aminopropyl)methylamine, 12 g / L of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, and 90 g / L of isooctyl alcohol, thereby adjusting the ratio of the pinhole inhibitor to the accelerator to 1:15.

[0115] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0116] Example 5

[0117] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the pinhole inhibitor is adjusted to 20 g / L (the concentration of 1-butylpyridinium chloride is 10 g / L, and the concentration of sodium chloride is 10 g / L), and the accelerator is adjusted to 160 g / L (50 g / L of N,N-bis(3-aminopropyl)methylamine, 14 g / L of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, and 96 g / L of isooctyl alcohol), so that the ratio of the pinhole inhibitor to the accelerator is 1:8.

[0118] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0119] Example 6

[0120] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the pinhole inhibitor is adjusted to 2.5 g / L of 1-butylpyridinium chloride and 2.5 g / L of sodium chloride, so that the ratio of the pinhole inhibitor to the accelerator is 1:50.

[0121] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0122] Example 7

[0123] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the accelerator contains 120 g / L of N,N-bis(3-aminopropyl)methylamine, 30 g / L of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, and 100 g / L of isooctyl alcohol, thereby adjusting the mass ratio of the amine compound to the alcohol compound in the accelerator to 1.5:1.

[0124] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0125] Example 8

[0126] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the N,N-bis(3-aminopropyl)methylamine, (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, and isooctyl alcohol in the accelerator are adjusted to 20 g / L, 21 g / L, and 209 g / L, respectively, so that the mass ratio of the amine compound to the alcohol compound in the accelerator is 0.2:1.

[0127] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0128] Example 9

[0129] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the accelerator contains 175 g / L of N,N-bis(3-aminopropyl)methylamine, 45 g / L of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole, and 30 g / L of isooctyl alcohol, thereby adjusting the mass ratio of the amine compound to the alcohol compound in the accelerator to 7:1.

[0130] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0131] Example 10

[0132] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the accelerator does not contain an alcohol compound. That is, the accelerator is replaced with 250 g / L of an amine compound, wherein the concentration of N,N-bis(3-aminopropyl)methylamine is 200 g / L, and the concentration of (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole is 50 g / L.

[0133] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0134] Example 11

[0135] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the accelerator does not contain an amine compound, that is, the accelerator is replaced by an alcohol compound at a concentration of 250 g / L, i.e., the concentration of isooctyl alcohol is 250 g / L.

[0136] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0137] Example 12

[0138] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the type of antioxidant is changed, that is, the antioxidant is replaced with sodium nitrilotriacetate of the same concentration.

[0139] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0140] Example 13

[0141] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that of Example 1 only in that the composition of the pinhole inhibitor is changed, that is, the pinhole inhibitor is replaced with 5.5 g / L 1-hexylpyridinium chloride and 4.5 g / L sodium chloride.

[0142] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0143] Example 14

[0144] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the concentration of 1-butylpyridinium chloride in the pinhole inhibitor is adjusted to 3 g / L and the amount of sodium chloride added is 7 g / L, thereby adjusting the mass ratio of the ionic liquid to the chloride salt solid in the pinhole inhibitor to 0.4:1.

[0145] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0146] Example 15

[0147] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the concentration of 1-butylpyridinium chloride in the pinhole inhibitor is adjusted to 8 g / L and the concentration of sodium chloride is adjusted to 2 g / L, thereby adjusting the mass ratio of the ionic liquid to the chloride salt solid in the pinhole inhibitor to 4:1.

[0148] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0149] Example 16

[0150] This embodiment provides a copper-reducing additive for HDI boards. The copper-reducing additive differs from that in Example 1 only in that the pinhole inhibitor uses only sodium chloride, and the concentration of the sodium chloride is 10 g / L.

[0151] This embodiment also provides a copper reduction process using the above copper reduction additive. The difference between the copper reduction process and embodiment 1 is that the time of the spray etching is adjusted in step (3) so that the etching amount of this embodiment is the same as that of embodiment 1.

[0152] Example 17

[0153] The present example provides a copper reducing additive for HDI board, which is different from example 1 only in that the pinhole inhibitor is only 1-butyl-4-methyl pyridinium chloride, and the concentration of 1-butyl-4-methyl pyridinium chloride is 10 g / L.

[0154] The present example also provides a copper reducing process using the above-mentioned copper reducing additive, which is different from example 1 only in that the time of spray etching in step (3) is adjusted so that the etching amount of the present example is the same as that in example 1.

[0155] Comparative example 1

[0156] The present comparative example provides a copper reducing additive for HDI board, which is different from example 1 only in that no accelerator is added.

[0157] The present comparative example also provides a copper reducing process using the above-mentioned copper reducing additive, which uses the operation in example 1, and due to the too low etching rate, the etching amount in example 1 cannot be reached.

[0158] Comparative example 2

[0159] The present comparative example provides a copper reducing additive for HDI board, which is different from example 1 only in that no pinhole inhibitor is added.

[0160] The present comparative example also provides a copper reducing process using the above-mentioned copper reducing additive, which is different from example 1 only in that the time of spray etching in step (3) is adjusted so that the etching amount of the present comparative example is the same as that in example 1.

[0161] Etching rate determination: the etching rate is calculated according to the mass of the filled hole plate in examples 1-17 and comparative examples 1-2, and the etching rate (μm / min) = (m1-m2) / (2×s×ρ)×10000; wherein m1 and m2 are the mass of the filled hole plate before and after spray etching, respectively; ρ is the density of copper, taken as 8.96 g / cm 3 ; S is the area of the filled hole plate, and the calculation results are shown in Table 1.

[0162] Pinhole determination: the copper-reduced filled hole plate is divided into 9 1×1 cm areas, and then etching solution is prepared according to examples 1-17 and comparative example 2 for copper reduction, and the time of spray etching is controlled so that the copper reduction thickness is 5 μm, and the copper-reduced filled hole plate is placed under a microscope, and the pinhole condition (number and size) at the blind hole is observed under 500 times magnification, and the total number of blind hole observations is 100. The blind hole yield is calculated, and the blind hole yield = number of blind holes without pinholes / 100×100%, and the results are shown in Table 1.

[0163] Etching solution stability test: Taking Example 1 as an example, the etching solution provided in Example 1 is used for continuous spray etching to test the rate stability and blind hole yield stability of the etching solution under continuous production conditions. The test method is: in the process of continuous production, the etching amount of each hole-filling plate is controlled to be 10μm; in the process of spray etching, an automatic adding device is used to add supplementary etching solution to the etching tank to replenish the components consumed in the etching solution, sulfuric acid, 35% hydrogen peroxide and copper-reducing additives are added to the automatic adding tank, and the addition amounts of sulfuric acid, hydrogen peroxide and copper-reducing additives are controlled to be 229g / L, 69g / L and 69mL / L respectively, to prepare the supplementary etching solution, and the automatic addition amount of the supplementary etching solution is controlled to be 3.26L / m 2 Plate, determination of different Cu 2+ Etching rate under concentration conditions. In order to ensure the accuracy of the test, the concentration of sulfuric acid and hydrogen peroxide in the etching solution in the etching tank needs to be analyzed before each rate test. If the concentration deviates greatly from the set value (the allowable deviation is generally ±3%), it needs to be manually added. The test obtains the etching rate fluctuation graph under continuous production conditions, such as Figure 1 As shown, from Figure 1 It can be seen that when Cu 2+ When the concentration is in the range of 0-55 g / L, the fluctuation range of sulfuric acid concentration is 143-145 g / L, and the fluctuation range of hydrogen peroxide concentration is 39.2-40.9 g / L. The fluctuation range of both is within the normal error range, that is, the concentrations of both are within the normal range. The test results show that the fluctuation range of the etching rate is 5.49-5.59 μm / min, indicating that the fluctuation range of the etching rate is very small, further indicating that the copper ion concentration has no effect on the etching rate within this range.

[0164] The test results show the fluctuation of blind hole yield under continuous production conditions, such as Figure 2 As shown, from Figure 2 It can be seen that the increase in copper ion concentration has no effect on the blind hole yield rate. Throughout the entire process, the blind hole yield rate remains stable at 100%.

[0165] Taking Example 1, Example 6 and Comparative Example 2 as examples, the microscope photos of the blind holes are as follows: Figure 3-5 As shown, from Figure 3-5 It can be seen that no pinholes appear in the blind holes obtained in Example 1, while pinholes appear in the blind holes obtained in Example 6 and Comparative Example 2.

[0166] Table 1

[0167]

[0168]

[0169] In Table 1, “-” indicates that the set etching amount could not be achieved, so there is no data.

[0170] The following points can be seen from the data in Table 1:

[0171] (1) It can be seen from the data of Examples 1-4, 7, and 12-13 that under optimal conditions, the copper-reducing additive and copper-reducing process provided by the present invention can achieve an etching rate of more than 5.52 μm / min and a blind hole yield of 100%.

[0172] (2) A comprehensive comparison of the data of Example 1, Examples 5-6, and Comparative Examples 1-2 shows that the only difference between Comparative Examples 1-2 and Example 1 is that the accelerator and pinhole inhibitor are not added. The data of Comparative Example 1 show that in the absence of the accelerator, the etching rate of the etching solution is very low, resulting in failure to use normally; the data of Comparative Example 2 show that in the absence of the pinhole inhibitor, the generation of pinholes cannot be suppressed, and the blind hole yield reaches only 10%. This shows that the present invention can achieve the effect of suppressing pinholes while increasing the etching rate through the synergistic effect of the accelerator and the pinhole inhibitor.

[0173] Furthermore, the only difference between Example 5-6 and Example 1 is that the ratio of the pinhole inhibitor to the accelerator is not within the preferred range of the present invention. In Example 5, the etching rate is reduced due to the excessively high mass ratio of the pinhole inhibitor to the accelerator. In Example 6, the etching rate is accelerated due to the excessively low mass ratio of the pinhole inhibitor to the accelerator, but the blind hole yield is reduced. It can be seen that the present invention preferably controls the mass ratio of the pinhole inhibitor to the accelerator, which can further improve the effect of suppressing pinholes while increasing the etching rate.

[0174] (3) A comprehensive comparison of the data of Example 1 and Examples 8-11 shows that the difference between Examples 10-11 and Example 1 is that only amine compounds or alcohol compounds are used as accelerators. By comparing Example 1 and Examples 10-11, it can be seen that although the etching rate of Example 10 is higher when only amine compounds are used, the pinhole inhibition effect is poor, resulting in a blind hole yield that is significantly lower than that of Example 1; Example 11 only uses alcohol compounds, and although the blind hole yield is higher, the etching rate is significantly lower than that of Example 1. This is because the amine compounds and alcohol compounds in the present invention have a synergistic effect. The higher the proportion of amine compounds in the accelerator, the faster the etching rate, but the blind hole yield decreases. On the contrary, the higher the proportion of alcohol compounds in the accelerator, the slower the etching rate, and the blind hole yield is basically unaffected. Therefore, the present invention uses amine compounds and alcohol compounds to cooperate with each other, which can achieve the effect of improving the etching rate while inhibiting pinholes.

[0175] Further, the difference between Example 8-9 and Example 1 is that the mass ratio of the amine compound and the alcohol compound is not within the preferred range of the present invention. In Example 8, due to the high proportion of alcohol compounds in the accelerator and the low proportion of amine compounds, although the alcohol compound is conducive to the diffusion of the amine compound on the copper surface, promotes the fragmentation and dissolution of the CuCl passivation film, and accelerates the reaction rate, when the proportion of amine compounds is too low, the mechanism of action of the alcohol compound is limited, so the etching rate is reduced, but the blind hole yield is basically unaffected; and in Example 9, due to the high proportion of amine compounds, the fragmentation and dissolution of the CuCl passivation film are promoted, the etching rate is accelerated, but the fragmentation and dissolution speed of the CuCl passivation film is too fast, which also leads to a poor passivation effect on copper, a shortened passivation time, and an increase in pinholes, and a decrease in the blind hole yield. It can be seen that the present invention preferably controls the mass ratio of amine compounds and alcohol compounds, which can further improve the effect of suppressing pinholes while improving the etching rate.

[0176] (4) A comprehensive comparison of the data of Example 1 and Examples 14-17 shows that the only difference between Examples 16-17 and Example 1 is that only chloride salt solid or chloride salt ionic liquid is used as the pinhole inhibitor. By comparing Example 1 with Examples 16-17, it can be seen that the etching rate in Example 16 is reduced, and although the etching rate in Example 17 is increased, the blind hole yield is reduced. This is because the present invention can simultaneously utilize Cl- and active N by using chloride salt solid and chloride salt ionic liquid to cooperate with each other. + Effect of species composition on R, Cl - Can form CuCl passivation film to inhibit pinhole formation, active N + Can form [Cu(N + R)]n passivation film inhibits pinhole formation, compared with [Cu(N + R)]n passivation film, CuCl passivation film has a stronger passivation effect, so it has a stronger inhibitory effect on etching rate and pinholes, but [Cu(N + The presence of the passivation film can make the distribution of the passivation film on the front copper surface more uniform and dense, thereby synergistically improving the pinhole suppression effect.

[0177] Furthermore, the only difference between Examples 14-15 and Example 1 is that the mass ratio of the chloride ionic liquid to the chloride solid is not within the preferred range of the present invention. In Example 14, due to the low mass ratio of the chloride ionic liquid to the chloride solid, Cl - The concentration of N is slightly higher than that of Example 1, resulting in a slightly lower etching rate in Example 14 compared to Example 1. +The concentration of R species is lower than that of Example 1, resulting in a lower blind hole yield in Example 14 compared to Example 1; and in Example 15, the mass ratio of chloride ionic liquid to chloride solid is too high, the concentration of Cl- is lower than that of Example 1, and N + The R species increased compared to Example 1, resulting in an increase in etching rate but a decrease in blind hole yield. This shows that the present invention preferably controls the mass ratio of chloride ionic liquid to chloride solid, which can further improve the effect of suppressing pinholes while increasing the etching rate.

[0178] In summary, the copper-reducing additive and copper-reducing process provided by the present invention can maintain a stable etching rate within a wide range of chloride ion concentrations, reduce the requirements of the etching solution on water quality, and maintain a stable etching rate at a higher upper limit of copper ion concentration (the upper limit of copper ions reaches 55 g / L or above). After copper reduction, no pinholes appear at the blind holes and copper surface of the filled plate, or the number of pinholes is reduced.

[0179] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A copper reducing additive for HDI boards, characterized in that: The copper-reducing additive comprises: Sulfuric acid 35-140g / L; Hydrogen peroxide stabilizer 10-50g / L; Pinhole inhibitor 5-20g / L; Accelerator 150-500g / L; Antioxidant 40-100g / L; The balance is water; The pinhole inhibitor includes a chloride salt; The chloride salt includes a chloride salt ionic liquid and a chloride salt solid; the mass ratio of the chloride salt ionic liquid to the chloride salt solid in the copper-reducing additive is (1-3):1; The chloride ionic liquids include 1-butylpyridinium chloride, 1-(2-oxopropyl)pyridinium chloride, 1-butyl-4-methylpyridinium chloride, 4-methyl-1-((2-methylthiazol-4-yl)methyl)pyridinium-1-chloride, 1-ethylpyridinium chloride, 1-(2-amino-2-oxoethyl)pyridinium chloride, 1-hexylpyridinium chloride, 1-(2-hydrazino-2-oxoethyl)pyridinium-1-chloride, -ammonium chloride, 3-ethyl-1-methyl-1H-imidazole-3-chloride, 1-allyl-3-vinylimidazolium chloride, 1-methyl-3-propyl-1H-imidazole-3-ammonium chloride, 2,3-dimethyl-1-octyl-1H-imidazole-3-ammonium chloride, 1-methyl-1-octylpyrrolidine-1-ammonium chloride or 1-ethyl-1-methylpyrrolidine-1-ammonium chloride, or a combination of at least two thereof; The accelerator includes an amine compound and an alcohol compound; the mass ratio of the amine compound to the alcohol compound in the copper-reducing additive is (0.5-4):1; The mass ratio of the pinhole inhibitor to the accelerator in the copper-reducing additive is 1:(10-25).

2. The copper-reducing additive according to claim 1, characterized in that The hydrogen peroxide stabilizer includes sulfonic acid compounds.

3. The copper-reducing additive according to claim 2, characterized in that The concentration of the sulfonic acid compound in the copper-reducing additive is 20-40 g / L.

4. The copper-reducing additive according to claim 2, characterized in that The sulfonic acid compound includes any one or a combination of at least two of taurine, 3-thio-isothioureapropylsulfonic acid, 1-amino-2-naphthol-4-sulfonic acid, 6-amino-1-naphthalenesulfonic acid, quinoline-8-sulfonic acid, N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid, N-tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid, 3-(N-morpholinyl)-2-hydroxypropanesulfonic acid, 3-amino-4-methoxybenzenesulfonic acid, (S)-2-amino-3-phenylpropane-1-sulfonic acid, piperazine-1,4-diethanesulfonic acid monosodium salt, sodium naphthalene-1-sulfonate, anthraquinone-2-sulfonic acid sodium salt or sodium isophenylpropanesulfonate.

5. The copper-reducing additive according to claim 1, characterized in that The concentration of the chloride ionic liquid in the copper-reducing additive is 3-15 g / L.

6. The copper-reducing additive according to claim 1, characterized in that: The concentration of chloride solid in the copper-reducing additive is 2-5 g / L.

7. The copper-reducing additive according to claim 1, characterized in that: The chloride salt solid includes sodium chloride.

8. The copper-reducing additive according to claim 1, characterized in that The concentration of the amine compound in the copper-reducing additive is 100-400 g / L.

9. The copper-reducing additive according to claim 1, characterized in that: The concentration of the alcohol compound in the copper-reducing additive is 50-400 g / L.

10. The copper-reducing additive according to claim 1, characterized in that: The amine compound includes any one or a combination of at least two of 3,5-dimethoxyaniline, 4-n-butylaniline, biuret, 2-((2-aminoethyl)amino)ethanol, N,N-dibutyl-1,3-propylenediamine, N'N-bis(3-aminopropyl)methylamine, N-acetylethylenediamine, 3,4-diaminobenzamidine, 2-aminopyrimidine, isocytosine, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole or 1,3-benzothiazol-5-amine.

11. The copper-reducing additive according to claim 1, characterized in that: The alcohol compound includes any one or a combination of at least two of sorbitol, 3-ethoxy-1-propanol, cyclohexanol, isobutanol, isooctyl alcohol, 4-amino-1-butanol, 2-amino-2-methyl-1,3-propanediol, 1,4-butynediol or 2,5-dimethyl-2,5-hexanediol.

12. The copper-reducing additive according to claim 1, characterized in that The antioxidant includes any one or a combination of at least two of ascorbic acid, sodium gluconate, glutaric acid, pimelic acid, sodium nitrilotriacetate, 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid or N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid.

13. A copper reduction process, characterized in that: The copper reduction process uses the copper reduction additive according to any one of claims 1 to 12; The copper reduction process comprises the following steps: (1) dissolving sulfuric acid, hydrogen peroxide stabilizer, pinhole inhibitor, accelerator and antioxidant in 50% of the formula amount of water, and then adding the remaining formula amount of water and stirring to obtain a copper-reducing additive; (2) preparing the copper-reducing additive obtained in step (1), sulfuric acid, hydrogen peroxide and water and heating them to obtain an etching solution; (3) The etching solution obtained in step (2) is used to spray-etch the hole-filled plate to obtain a hole-filled plate with reduced copper.

14. The copper reduction process according to claim 13, characterized in that: The amount of sulfuric acid added to the etching solution in step (2) is 140-220 g / L.

15. The copper reduction process according to claim 13, characterized in that: The amount of the copper-reducing additive added to the etching solution is 40-60 mL / L.

16. The copper reduction process according to claim 13, characterized in that: Copper sulfate pentahydrate is also added to the etching solution.

17. The copper reduction process according to claim 16, characterized in that: The amount of copper sulfate pentahydrate added to the etching solution is 20-220 g / L.

18. The copper reduction process according to claim 13, characterized in that: The amount of hydrogen peroxide added to the etching solution is 32-48 g / L.

19. The copper reduction process according to claim 13, characterized in that: The spray etching in step (3) is performed in an etching tank.

20. The copper reduction process according to claim 19, characterized in that: The upper spray pressure of the spray etching is 2.0-2.3 kg / cm 2 .

21. The copper reduction process according to claim 19, characterized in that: The spray pressure of the spray etching is 1.1-1.4 kg / cm 2 .

22. The copper reduction process according to claim 19, characterized in that: The temperature of the spray etching is 36-40°C.

23. The copper reduction process according to claim 13, characterized in that: The etching amount of each hole-filling plate is 5-15 μm.

24. The copper reduction process according to claim 13, characterized in that: The etching time of each hole-filling plate is 90-330s.

25. The copper reduction process according to claim 13, characterized in that: When the copper reduction process is carried out under continuous conditions, during the spray etching process in step (3), an automatic adding device is used to add additional etching solution to the etching tank.

26. The copper reduction process according to claim 25, characterized in that: The supplementary etching solution is prepared by using a copper-reducing additive, sulfuric acid and hydrogen peroxide.

27. The copper reduction process according to claim 25, characterized in that: The amount of the copper-reducing additive added to the supplementary etching solution is 59-79 mL / L.

28. The copper reduction process according to claim 25, characterized in that: The amount of sulfuric acid added to the supplementary etching solution is 230-300 g / L.

29. The copper reduction process according to claim 25, characterized in that: The amount of hydrogen peroxide added to the supplementary etching solution is 61-77 g / L.

30. The copper reduction process according to claim 25, characterized in that: The amount of etching solution added to the etching tank is 1.63-4.89 L / m 2 plate.

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