A hole-filling organic additive for MSAP and copper electroplating solution

Abstract

The present invention provides an organic copper electroplating additive and copper electroplating solution for MSAP, comprising a leveler, an accelerator, and an inhibitor. The leveler is a product formed by the reaction of a carbonyl compound, an aliphatic amine compound, and a glycidyl ether. The copper electroplating solution comprises copper sulfate, a sulfuric acid electrolyte, and the organic copper electroplating additive added to the electrolyte. The present invention can perfectly fill micro-holes on substrates containing blind or X-shaped holes, effectively improving the post-filling protrusion effect, significantly addressing the problem of circuit arcs and promoting the quality and reliability of the MSAP process. The leveler of the present invention incorporates a heterocyclic N compound containing a double-bond group. While maintaining the hole-filling capability, the leveler achieves more uniform charge dispersion, resulting in more balanced adsorption and desorption in high-potential regions. In actual hole-filling production, the leveler of the present invention can effectively improve the post-filling protrusion effect, regardless of whether the jet is strong or weak, or the current density is large or small.

Description

Technical Field

[0001] The invention relates to the technical field of hole-filling additives, in particular to an organic hole-filling additive for MSAP and a copper electroplating solution. Background Art

[0002] With the development of science and technology, some high-tech products and equipment are becoming more and more intelligent, miniaturized and sophisticated, which places higher and higher requirements on the PCB boards they use.

[0003] It is required to further reduce the aperture of the via hole and the line width and line spacing of the line to achieve high-density wiring of the line and meet its high-speed, high-frequency, high thermal conductivity and high-performance performance requirements.

[0004] This poses a new challenge to PCB production. Existing subtractive processes are difficult to meet the production requirements of fine lines with a line width and line spacing of 50um or less, so the MSAP (semi-additive process) technology came into being.

[0005] The biggest feature of the MSAP process is that the surface plating thickness is thinner and more uniform, and the board cannot be ground after the process is completed. This poses new challenges to the hole filling solution. Currently, there are two types of hole filling technologies on the market:

[0006] (1) A hole-filling copper plating solution containing a reaction condensation of aliphatic amine compounds and glycidyl ether or a quaternized ammonium derivative of the condensate as a leveling agent; the characteristics of this type of solution are: good board surface appearance, blind holes can be filled stably without gaps, but the hole-filling performance is weak, and a thicker surface copper plating layer (20 to 25 microns) is required to fill it, which is not conducive to the production of fine circuits;

[0007] (2) Reactants of heterocyclic compounds such as imidazoles and glycidyl ethers; the characteristics of this type of solution are: fast hole filling speed, strong burst ability, and thin surface copper (12 to 15 microns). However, when this type of solution is used to fill holes in graphic circuit boards, the micro holes are prone to bulge after filling, and the circuit arc is too large, which is also not conducive to circuit quality control. Summary of the Invention

[0008] In view of the shortcomings of the prior art, the present invention provides an organic copper electroplating additive for MSAP and a copper electroplating solution containing the additive, which is used to improve the protrusion effect after micro-hole filling and thus improve the circuit arc.

[0009] The technical solution of the present invention is: an organic additive for electroplating copper in MSAP, comprising a leveler, wherein the leveler is a product generated by the reaction of a carbonyl compound, an aliphatic amine compound, and a glycidyl ether; and the molar ratio of the carbonyl compound, the aliphatic amine compound, and the glycidyl ether is (0.1-3):(0.1-3):1.

[0010] Preferably, the dosage of the leveling agent is 5-100 ppm.

[0011] Preferably, the chemical structural formulas of the carbonyl compound, aliphatic amine compound, and glycidyl ether are:

[0012] The structural formula of the carbonyl compound is:

[0013]

[0014] The structural formula of the fatty amine compound is:

[0015] NH2-R1-NH2;

[0016] The chemical structural formula of the glycidyl ether is:

[0017]

[0018] Wherein, A is an O, N, or S element, more preferably an O or N element; R1 is a C2-C4 alkylene group or a C2-C4 iminoalkyl group; R is a non-epoxy linking group selected from a substituted or unsubstituted C1-C10 alkylene group or an -OBO- group, wherein B is a substituted or unsubstituted C1-C10 alkylene group.

[0019] Preferably, the carbonyl compound is urea or guanidine; the fatty amine compound is ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, or triethylenetetramine;

[0020] The glycidyl ether is selected from 1,2-propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, 1,2,7,8-diepoxyoctane, 1,10-decanediol diglycidyl ether, or 1,8-octanediol diglycidyl ether.

[0021] Preferably, the structural formulas of the products generated by the reaction of the carbonyl compound, the fatty amine compound, and the glycidyl ether are shown in (4-1) to (4-8):

[0022]

[0023]

[0024]

[0025] Preferably, the additive further comprises an accelerator and an inhibitor, and the dosage of the accelerator and the inhibitor are 0.5-50 ppm and 200-3000 ppm respectively, more preferably 1-10 ppm for the accelerator and 400-800 ppm for the inhibitor.

[0026] Preferably, the accelerator is selected from one or more compounds represented by structural formulas (5-1) to (5-4):

[0027]

[0028] HS-CH2-COOK(5-3);

[0029] NaSO3-CH2-CH2-CH2-SS-CH2-CH2-CH2-SO3Na(5-4).

[0030] Preferably, the inhibitor is selected from one or more components selected from polyethylene glycol, polypropylene glycol, ethylenediamine polyoxyethylene polyoxypropylene adduct, butyl-terminated polyoxyethylene polyoxypropylene ether, random polyoxyethylene polyoxypropylene block polyether, and random polyoxyethylene polyoxypropylene polyoxyethylene block polyether, and the molar molecular weight is generally controlled between 1000 and 30000.

[0031] Preferably, the present invention also provides a method for preparing a leveling agent, comprising the following steps:

[0032] S1) Mix the carbonyl compound and the aliphatic amine compound and heat the reaction mixture to 130°C within 20 minutes; moderate ammonia formation is observed after a period of reaction; the reaction mixture is maintained at 130°C overnight; after the reaction is complete, any residual ammonia is removed by distillation under reduced pressure at 50°C; a clear, light yellow, viscous liquid is obtained;

[0033] S2), the reactant in step S1) was added to pure water, stirred and dissolved, and then poured into a round-bottom three-necked flask equipped with a condenser and a thermometer. Glycidyl ether was added dropwise to react with the reaction mixture at a bath temperature of 80°C. The reaction was kept at 90°C for 8 hours, then cooled and 50% sulfuric acid was added to adjust the pH to 2-3. The product was used without purification.

[0034] Preferably, the present invention further provides a copper electroplating solution comprising copper sulfate, a sulfuric acid electrolyte, and an organic copper electroplating additive, wherein the organic copper electroplating additive comprises:

[0035] The dosage of the accelerator and inhibitor is 0.5-50ppm and 200-3000ppm respectively.

[0036] The dosage of the leveling agent is 5-100ppm.

[0037] The beneficial effects of the present invention are:

[0038] 1. The present invention can perfectly fill micro-holes on substrates containing blind and X-shaped hole patterns, effectively improve the protrusion effect after micro-hole filling, greatly improve the circuit arc problem, and help improve the quality and reliability of the MSAP process;

[0039] 2. The leveler of the present invention introduces a heterocyclic N compound containing a double-bond group. While maintaining the hole-filling capability, the charge dispersion of the leveler is more uniform, resulting in more balanced elution and adsorption in the high-potential region. In actual hole-filling production, the leveler of the present invention can effectively improve the protrusion effect after hole filling, regardless of whether the jet is strong or weak or the current density is large or small.

[0040] 3. After the electroplating copper additive of the present invention is used for MSAP pattern hole filling electroplating, the X-shaped hole filling effect is good, the X-shaped hole is basically filled without protrusion, the circuit arc is within 20%, and the unit pattern height difference is within 4um. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a cross-section diagram of the additive-filled hole electroplating of Example 3 of the present invention;

[0042] Figure 2 This is a circuit arc diagram after the additive pattern is filled in Example 3 of the present invention;

[0043] Figure 3 This is a cross-section diagram of the additive-filled hole electroplating of Comparative Example 1 of the present invention;

[0044] Figure 4 This is a circuit arc diagram after electroplating of the additive pattern hole filling in comparative example 1 of the present invention;

[0045] Figure 5 This is a cross-section diagram of the additive-filled hole electroplating of Comparative Example 2 of the present invention;

[0046] Figure 6 This is a circuit arc diagram after additive pattern hole filling electroplating in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0047] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0048] Example 1

[0049] Preparation of leveling agent

[0050] Step 1: A 250 mL round-bottom flask was charged with 29.53 g (500 mmol) of guanidine and 51.6 g (500 mmol) of diethylenetriamine; the reaction mixture was heated to 130°C over 20 minutes; after a period of reaction, moderate ammonia formation was observed; the reaction mixture was maintained at 130°C overnight; upon completion of the reaction, any residual ammonia was removed by distillation under reduced pressure at 50°C; 70 g of a clear, pale yellow, viscous liquid was obtained;

[0051] Step 2: Add 70 g of the above reaction product into 200 ml of pure water, stir and dissolve, then pour into a 500 mL round-bottom three-necked flask equipped with a condenser and a thermometer. When the bath temperature is 80 ° C, 50.5 g (250 mmol) of 1,4-butanediol diglycidyl ether is added dropwise to the reaction mixture. Keep the reaction at 90 ° C for 8 hours, then cool and add 50% sulfuric acid to adjust the pH to 2-3. The product can be used without purification.

[0052] Example 2

[0053] Preparation of leveling agent

[0054] Step 1: A 250 mL round-bottom flask was charged with 30 g (500 mmol) of urea and 51.6 g (500 mmol) of diethylenetriamine; the reaction mixture was heated to 130° C. over 20 minutes; moderate ammonia formation was observed after a period of reaction; the reaction mixture was maintained at 130° C. overnight; upon completion of the reaction, any residual ammonia was removed by distillation under reduced pressure at 50° C.; 71 g of a clear, pale yellow, viscous liquid was obtained;

[0055] Step 2: Add 71 g of the above reaction product into 200 ml of pure water, stir and dissolve, then pour into a 500 mL round-bottom three-necked flask equipped with a condenser and a thermometer. When the bath temperature is 80 ° C, 50.5 g (250 mmol) of 1,4-butanediol diglycidyl ether is added dropwise to the reaction mixture. Keep the reaction at 90 ° C for 8 hours, then cool it down, add 50% sulfuric acid to adjust the pH to 2-3, and the product can be used without purification.

[0056] Example 3

[0057] Via filling copper plating solution

[0058]

[0059]

[0060] Inhibitor* refers to random polyoxyethylene polyoxypropylene block polyether;

[0061] Accelerator* refers to sodium salt of polydisulfide propane sulfonate.

[0062] Example 4

[0063] Via filling copper plating solution

[0064]

[0065] Inhibitor* refers to random polyoxyethylene polyoxypropylene block polyether;

[0066] Accelerator* refers to sodium salt of polydisulfide propane sulfonate.

[0067] Examples 5-10

[0068] The examples are basically the same as Example 3, except for the different levelers. The levelers of the copper electroplating solutions of Examples 5-10 respectively use the compounds described in the structural formulas (4-3) to (4-8) of the present invention.

[0069] Comparative Example 1

[0070] The process is basically the same as Example 3, except that the leveling agent is different. The leveling agent used in Comparative Example 1 is the condensation reaction product of N,N,N,N,propylene diamine and glycidyl ether.

[0071] Comparative Example 2

[0072] The process is basically the same as Example 3, except that the leveling agent is different. The leveling agent used in Comparative Example 1 is a condensation reaction product of imidazole and glycidyl ether.

[0073] The above examples were conducted in a Haring cell, using bottom air agitation and an insoluble anode. The experiments used patterned hole-filled substrates with a dielectric thickness of 200 μm, upper and lower apertures of 80 / 100 μm, and X-shaped holes measuring 5.5 cm by 15 cm. Prior to hole-filling, the substrates had undergone copper plated treatment. After acid degreasing and pickling pretreatment, the substrates were contacted with the above-described hole-filling copper plating solution. A current density of 14 ASF was applied to the substrates for 65 minutes. The samples after hole-filling were then analyzed to determine their hole-filling capability, throwing power, and pattern circuit arc ratio.

[0074] Hole-filling capability is assessed using the dimple value, which measures the distance between the lowest point of the copper layer in the hole and the copper layer on the test board surface. A positive value closer to 0 indicates better hole-filling capability for the plating solution and its leveler. Conversely, a more negative dimple value indicates greater micro-hole protrusion after filling, indicating excessive hole-filling capability.

[0075] The throwing power is evaluated by measuring the thickness range of the metal deposit layer at different positions in the unit pattern. The smaller the thickness range of the metal layer in the unit pattern, the better the throwing power of the electroplating copper solution and the leveler compound therein.

[0076] The arc rate of the circuit represents the flatness of the circuit shape. The smaller the value, the higher the flatness of the copper electroplating solution and the leveling agent compound in it for fine circuit processing. The arc rate is calculated by the following formula:

[0077] Arc rate % = (height center - height edge) / height edge;

[0078] The "height center" is the height of the line measured along its axis; the "height edge" is the height of the thin line measured along its edge.

[0079] After the electroplating verification experiment was completed, each test board was sliced ​​and the dimple value of the filled hole, the arc rate of the circuit, the surface plating thickness of the filled surface within the unit pattern, and the thickness difference between the large copper surface and the circuit were measured. The results are shown in Table 1.

[0080] Example Dimple Unit graphic height difference Arc rate Example 3 0.64um 1.74um 18.24％ Example 4 0.60um 2.01um 17.88％ Example 5 0.58um 1.34um 16.24％ Example 6 0.44um 1.52um 18.36％ Example 7 1.64um 2.74um 19.24％ Example 8 1.33um 2.59um 15.88％ Example 9 0.97um 1.25um 18.65％ Example 10 0.84um 2.44um 17.76％ Comparative Example 1 24.28um 3.34um 24.62％ Comparative Example 2 -6.56um 2.56um 31.25％

[0081] From Table 1, Appendix Figure 1-6 It can be seen that after the copper plating additive of the present invention is used for MSAP pattern filling electroplating, the X-shaped holes are filled effectively. The X-shaped holes are basically filled flat with no protrusions, the circuit arc is within 20%, and the unit pattern height difference is within 4μm. All three indicators meet industry requirements, indicating that the organic additive for filling MSAP holes of the present invention has excellent filling performance. The use of the leveling agent of the present invention can ensure the filling of micro-holes and improve the protrusion problem after micro-hole filling, thereby improving the quality of fine circuit arc. At the same time, the pattern filling effects of Comparative Examples 1 and 2 are shown. Comparative Example 1 uses a leveling agent to fill the pattern poorly, and the X-shaped hole filling depression value is relatively large, reaching approximately 24μm. While Comparative Example 2 has good X-shaped hole filling effect, but the micro-holes are significantly convex after filling, and the circuit arc rate is poor, which does not meet industry quality control requirements.

[0082] A comparison of the MSAP pore-filling performance of the present invention's examples and Comparative Examples 1-2 demonstrates that the key functional component of the MSAP organic additive of the present invention is the leveler. The leveler incorporates a heterocyclic N compound containing a double-bond group, ensuring pore-filling capability while achieving more uniform charge dispersion and resulting in more balanced elution and adsorption in high-potential regions. In actual pore-filling production, the leveler of the present invention effectively improves the post-filling protrusion effect, regardless of strong or weak jet flow or current density. In contrast, the levelers of Comparative Examples 1-2 struggle to achieve this pore-filling effect, resulting in a poor rounding rate.

[0083] To keep the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in any combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above embodiments and descriptions are only for explaining the principles and best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, which shall fall within the scope of the invention to be protected.

Claims

1. An organic additive for copper electroplating in MSAP, characterized in that: The invention comprises a leveling agent, wherein the leveling agent is a product generated by the reaction of a carbonyl compound or an imine compound, an aliphatic amine compound, and a glycidyl ether; and the molar ratio of the carbonyl compound or the imine compound, the aliphatic amine compound, and the glycidyl ether is (0.1-3): (0.1-3): 1; The structural formula of the carbonyl compound or imine compound is: ； The structural formula of the fatty amine compound is: ； The chemical structural formula of the glycidyl ether is: ； Wherein, A is O or N; R1 is C2-C4 alkylene or C2-C4 iminoalkyl; R is a group of -OBO-, wherein B is a substituted or unsubstituted C1-C10 alkylene; The structural formula of the product generated by the reaction of the imine compound, the fatty amine compound and the glycidyl ether is: （4-1） （4-4） （4-6） （4-7）； The preparation of the leveling agent comprises the following steps: S1) Mix a carbonyl compound or an imine compound and an aliphatic amine compound and heat the reaction mixture to 130°C within 20 minutes; moderate ammonia formation may be observed after a period of reaction; maintain the reaction at 130°C overnight; after completion of the reaction, remove any residual ammonia by distillation under reduced pressure at 50°C; obtain a clear, light yellow, viscous liquid; S2), the reactant in step S1) was added to pure water, stirred and dissolved, and then poured into a round-bottom three-necked flask equipped with a condenser and a thermometer. Glycidyl ether was added dropwise to react with the reaction mixture at a bath temperature of 80°C. The reaction was kept at 90°C for 8 hours, then cooled and 50% sulfuric acid was added to adjust the pH to 2-3. The product was used without purification.

2. The organic additive for copper electroplating of MSAP according to claim 1, characterized in that: The dosage of the leveling agent is 5-100ppm.

3. The organic additive for copper electroplating of MSAP according to claim 1, characterized in that: The carbonyl compound is urea; the fatty amine compound is ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, and triethylenetetramine; The glycidyl ether is selected from 1,2-propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, 1,2,7,8-diepoxyoctane, 1,10-decanediol diglycidyl ether, or 1,8-octanediol diglycidyl ether.

4. The organic additive for copper electroplating of MSAP according to claim 3, characterized in that: The structural formula of the product generated by the reaction of the carbonyl compound, the fatty amine compound and the glycidyl ether is as follows: （4-2） （4-3） （4-5） （4-8）。 5. The organic additive for electroplating copper in MSAP according to claim 4, characterized in that: The additives also include an accelerator and an inhibitor, and the dosage of the accelerator and the inhibitor are 0.5-50ppm and 200-3000ppm respectively.

6. The organic additive for copper electroplating of MSAP according to claim 5, characterized in that: The accelerator is selected from one or more compounds represented by structural formulas (5-1) to (5-4): 5-1）； （5-2）； HS-CH2-COOK (5-3); NaSO3-CH2-CH2-CH2-SS-CH2-CH2-CH2-SO3Na (5-4).

7. The organic additive for copper electroplating of MSAP according to claim 5, characterized in that: The inhibitor is selected from one or more components of polyethylene glycol, polypropylene glycol, ethylenediamine polyoxyethylene polyoxypropylene adduct, butyl-terminated polyoxyethylene polyoxypropylene ether, random polyoxyethylene polyoxypropylene block polyether, and random polyoxyethylene polyoxypropylene polyoxyethylene block polyether, and the molar molecular weight is generally controlled between 1000 and 30000.

8. A copper electroplating solution, characterized in that: The invention comprises copper sulfate, a sulfuric acid electrolyte, and the electroplating copper organic additive according to any one of claims 5 to 7 added to the electrolyte, wherein the electroplating copper organic additive comprises: the accelerator and the suppressor in amounts of 0.5-50 ppm and 200-3000 ppm, respectively; and the leveler in an amount of 5-100 ppm.

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