Electrocoppering method for filling through hole of IC (integrated circuit) support plate

Abstract

The invention discloses a copper electroplating method for filling a through hole of an IC (integrated circuit) support plate, and belongs to the technical field of electroplating. According to the copper electroplating method, deionized water is used for spraying an IC carrier plate, stirring, circulating and swinging operation is carried out in a copper electroplating solution containing tank, then the IC carrier plate is placed in a copper electroplating solution for electroplating, and the copper electroplating solution comprises copper methanesulfonate, methanesulfonic acid, chloride ions, sodium 3, 3 '-dithiodipropane sulfonate (SPS), polyethylene glycol, benzotriazole, 3, 3'-dithiodipropane sulfonate (SPS), polyethylene glycol, benzotriazole, 3, 3 '-dithiodipropane sulfonate (SPS), polyethylene glycol, benzotriazole, 2, 3'-dithiodipropane sulfonate (SPS), polyethylene glycol, benzotriazole, 2, 3 '- and 3, 3 '-dimethoxy benzidine hydrochloride and deionized water. Through testing, the plating layer is obtained, the plating layer is smooth, uniform and fine, the through hole does not have a cavity phenomenon after electroplating, and the reliability of an electronic product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating, and in particular to a copper electroplating method for filling a through hole of an IC carrier. Background Art

[0002] Integrated circuit (IC) substrate is a key material used to connect IC chips and PCBs, protecting the chips and serving as a transmission port between the chips and the outside world. In order to make IC substrates meet the requirements of high precision and high integration, the development of through-hole electroplating filling has become a hot topic in the field of microelectronics.

[0003] The most common through-hole electroplating for IC substrates is copper filling, but copper plating of through-holes is prone to voids, holes, and gaps. At present, the industry mainly reduces the voids, holes, and gaps in through-holes by designing more complex hole filling processes or by pulse electroplating. However, the complex hole filling process undoubtedly increases the cost of industrialization, quality, and control difficulties, and is not a good solution. The electroplating process of pulse electroplating is complex and requires a huge equipment cost.

[0004] In view of this, the present invention provides a copper electroplating method for filling a through hole of an IC substrate. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a copper electroplating method for filling IC substrate through holes to solve the problems of voids, gaps and other defects in the IC substrate through hole electroplating process, and the high cost of pulse electroplating equipment. It can effectively prevent the shortcomings of unstable signal transmission, high resistance, excessive power loss and the like caused by voids, and further improve the reliability of electronic products.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A copper electroplating method for filling a through hole of an IC substrate comprises the following steps:

[0008] Step S1: IC substrate pretreatment: spraying with deionized water;

[0009] Step S2: electroplating.

[0010] Furthermore, in step S1, the spray treatment is used to allow deionized water to enter the through-holes, and to use the pressure of the spray to discharge the air inside the through-holes of the IC substrate, thereby preventing bubbles from being trapped in the center of the through-holes and affecting the electroplating effect.

[0011] Furthermore, in step S1, the IC substrate after the spray treatment is placed in a copper electroplating solution tank for stirring, circulation and swinging operations to accelerate the flow of the copper electroplating solution, so that the copper ions and additives in the electroplating solution enter the through holes of the IC substrate, ensuring that the plating solution has sufficient copper ions and additives in the through holes.

[0012] Furthermore, in step S1, the spraying time is between 5 and 10 minutes.

[0013] Furthermore, in step S1, the stirring rate is between 100-200 r / min.

[0014] Further, in step S2, the electroplating includes: placing the pretreated carrier in a copper electroplating solution, using the phosphor copper material as the anode and the carrier as the cathode, passing direct current during the electroplating process at 40-45°C, using a step-type electroplating process, and in the initial stage, using a current interval of 2s at 2.5A / dm 2 The current density is 20-30min for electroplating; in the transition stage, the current interval is 2s, 2.5-3.0A / dm 2 The current density is 20-30min, and the final stage is 3.0A / dm at a current interval of 2s. 2 The current density is 20-30 minutes.

[0015] Further, in step S2, the copper electroplating solution includes the following components according to concentration: copper methanesulfonate: 190-220 g / L, methanesulfonic acid: 40-60 g / L, chloride ion: 30-40 mg / L, sodium polydisulfide propane sulfonate (SPS): 1-10 mg / L, polyethylene glycol: 150-300 mg / L, benzotriazole: 100-180 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 1-10 mg / L, and deionized water: the balance.

[0016] Furthermore, in step S2, the chloride ions are provided by one or more of cupric chloride dihydrate, sodium chloride or hydrochloric acid, which can improve the brightness and leveling ability of the copper on the surface of the IC substrate and the copper metal in the hole, and improve the electroplating quality of the IC substrate.

[0017] Furthermore, in step S2, the sodium polydisulfide dipropane sulfonate contains sulfur substances in the additive component, which can be adsorbed onto the surface of the conductive layer and the inside of the through hole. It is an inhibitor with weak inhibition ability, and its main function is to accelerate the copper plating effect and make the surface of the IC substrate bright.

[0018] Furthermore, in step S2, the polyethylene glycol is selected from any one of polyethylene glycol-4000, polyethylene glycol-6000, polyethylene glycol-8000, and polyethylene glycol-10000, or a combination of any proportions of any two of them.

[0019] Furthermore, in step S2, the current density and the electroplating time may be adjusted according to the diameter and depth of the through hole of the IC substrate.

[0020] A copper electroplating method for filling a through hole of an IC substrate comprises the following steps:

[0021] Step S1: spraying the IC substrate with deionized water for 5-10 minutes, and stirring, circulating and swinging at 100-200 r / min in a tank containing electroplating copper solution;

[0022] Step S2: Place the substrate pretreated in step S1 in a copper electroplating solution, with the phosphor copper material as the anode and the substrate as the cathode. Direct current is applied during the electroplating process at 40-45°C, using a step-type electroplating process. In the initial stage, the current is 2.5A / dm at 2s intervals. 2 The current density is 20-30min for electroplating; in the transition stage, the current interval is 2s, 2.5-3.0A / dm 2 The current density is 20-30min, and the final stage is 3.0A / dm at a current interval of 2s. 2 The current density is 20-30 minutes for electroplating; wherein the copper electroplating solution comprises the following components according to concentration: copper methanesulfonate: 190-220 g / L, methanesulfonic acid: 40-60 g / L, chloride ion: 30-40 mg / L, sodium polydisulfide propane sulfonate (SPS): 1-10 mg / L, polyethylene glycol: 150-300 mg / L, benzotriazole: 100-180 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 1-10 mg / L, and deionized water: the balance.

[0023] The beneficial effects of the present invention are as follows: compared with the prior art, the copper electroplating method for filling the through-holes of an IC carrier provided by the present invention has the following advantages:

[0024] The present invention adopts low-cost DC power supply electroplating to obtain IC carrier through-holes without cavities or gaps inside the through-holes, which can effectively prevent the defects of unstable signal transmission, high resistance, excessive power loss, etc. caused by cavities and gaps, and further improve the reliability of electronic products. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, some non-limiting embodiments are further disclosed below to further illustrate the present invention in detail.

[0026] The reagents used in the present invention can be purchased from the market or prepared by the method described in the present invention.

[0027] Example 1

[0028] Prepare copper electroplating solution:

[0029] The formula composition is as follows: copper methanesulfonate: 200g / L, methanesulfonic acid: 50g / L, chloride ion: 40mg / L, sodium polydisulfide propane sulfonate (SPS): 5mg / L, polyethylene glycol-4000: 200mg / L, benzotriazole: 150mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5mg / L, deionized water: balance.

[0030] Solution preparation process: Taking 1L solution as an example, take 300ml of water, add copper methanesulfonate: 200g; methanesulfonic acid: 50g, sodium chloride: 0.04g, sodium polydisulfide propane sulfonate (SPS): 0.005g; polyethylene glycol-4000: 0.2g; benzotriazole: 0.15g, 3,3'-dimethoxybenzidine hydrochloride: 0.005g, stir to dissolve, and then add water to the liquid level to 1L.

[0031] Electroplated copper filling IC substrate through-holes:

[0032] S1: The IC substrate is sprayed with deionized water for 5 minutes, and stirred, circulated and swung at 1500r / min in a tank containing electroplating copper solution;

[0033] S2: Place the substrate pretreated in step S1 in a copper electroplating solution, with the phosphor copper material as the anode and the substrate as the cathode. Direct current is applied during the electroplating process at 40°C, using a step-type electroplating process. In the initial stage, the current interval is 2s and the current is 2.5A / dm 2 The current density was 2.8A / dm2 for 2s in the transition phase. 2 The current density was 3.0A / dm2 for 25min; in the final stage, the current interval was 2s. 2 The current density was 2.0 and the electroplating time was 30 min.

[0034] Example 2

[0035] Prepare copper electroplating solution:

[0036] The formula composition is as follows: copper methanesulfonate: 190 g / L, methanesulfonic acid: 40 g / L, chloride ion: 35 mg / L, sodium polydisulfide propane sulfonate (SPS): 1 mg / L, polyethylene glycol-6000: 150 mg / L, benzotriazole: 100 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L, deionized water: balance.

[0037] Solution preparation process: Taking 1L solution as an example, take 300ml of water, add copper methanesulfonate: 190g; methanesulfonic acid: 40g, cupric chloride dihydrate: 0.035g, sodium polydisulfide propane sulfonate (SPS): 0.005g; polyethylene glycol-6000: 0.2g; benzotriazole: 0.10g, 3,3'-dimethoxybenzidine hydrochloride: 0.005g, stir to dissolve, and then add water to the liquid level to 1L.

[0038] Electroplated copper filling IC substrate through-holes:

[0039] S1: The IC substrate is sprayed with deionized water for 5 minutes, and stirred, circulated and swung at 1500r / min in a tank containing electroplating copper solution;

[0040] S2: Place the substrate pretreated in step S1 in a copper electroplating solution, with the phosphor copper material as the anode and the substrate as the cathode. Direct current is applied during the electroplating process at 40°C, using a step-type electroplating process. In the initial stage, the current interval is 2s and the current is 2.5A / dm 2 The current density was 2.8A / dm2 for 2s in the transition phase. 2 The current density was 3.0A / dm2 for 25min; in the final stage, the current interval was 2s. 2 The current density was 2.0 and the electroplating time was 30 min.

[0041] Example 3

[0042] Prepare copper electroplating solution:

[0043] The formula composition is as follows: copper methanesulfonate: 220g / L, methanesulfonic acid: 60g / L, chloride ion: 30mg / L, sodium polydisulfide propane sulfonate (SPS): 10mg / L, polyethylene glycol-8000: 300mg / L, benzotriazole: 180mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5mg / L, deionized water: balance.

[0044] Solution preparation process: Taking 1L solution as an example, take 300ml of water, add copper methanesulfonate: 200g; methanesulfonic acid: 50g, hydrochloric acid: 0.03g, sodium polydisulfide propane sulfonate (SPS): 0.01g; polyethylene glycol-8000: 0.3g; benzotriazole: 0.18g, 3,3'-dimethoxybenzidine hydrochloride: 0.005g, stir to dissolve, and then add water to the liquid level to 1L.

[0045] Electroplated copper filling IC substrate through-holes:

[0046] S1: The IC substrate is sprayed with deionized water for 5 minutes, and stirred, circulated and swung at 1500r / min in a tank containing electroplating copper solution;

[0047] S2: Place the substrate pretreated in step S1 in a copper electroplating solution, with the phosphor copper material as the anode and the substrate as the cathode. Direct current is applied during the electroplating process at 40°C, using a step-type electroplating process. In the initial stage, the current interval is 2s and the current is 2.5A / dm 2 The current density was 2.8A / dm2 for 2s in the transition phase. 2 The current density was 3.0A / dm2 for 25min; in the final stage, the current interval was 2s. 2 The current density was 2.0 and the electroplating time was 30 min.

[0048] Comparative Example 1

[0049] Specific implementation method is the same as Example 1, except that, in the copper electroplating solution, sodium polydisulfide bispropane sulfonate (SPS): 0.5 mg / L, polyethylene glycol-4000: 100 mg / L, L-benzotriazole: 50 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0050] Comparative Example 2

[0051] Specific implementation method is the same as Example 1, except that, in the copper electroplating solution, sodium poly(dipropane disulfide) (SPS): 5 mg / L, polyethylene glycol-4000: 200 mg / L, benzotriazole: 50 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0052] Comparative Example 3

[0053] Specific implementation method is the same as Example 1, except that, in the copper electroplating solution, sodium poly(dipropylene glycol) sulfonate (SPS) is 5 mg / L, polyethylene glycol-4000 is 100 mg / L, benzotriazole is 150 mg / L, and 3,3'-dimethoxybenzidine hydrochloride is 5 mg / L.

[0054] Comparative Example 4

[0055] Specific implementation method is the same as Example 1, except that, in the copper electroplating solution, sodium polydisulfide bispropane sulfonate (SPS): 0.5 mg / L, polyethylene glycol-4000: 200 mg / L, benzotriazole: 150 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0056] Comparative Example 5

[0057] Specific implementation method is the same as Example 2, except that, in the copper electroplating solution, sodium polydisulfide bispropane sulfonate (SPS): 0.5 mg / L, polyethylene glycol-6000: 100 mg / L, benzotriazole: 50 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0058] Comparative Example 6

[0059] Specific implementation method is the same as Example 2, except that, in the copper electroplating solution, sodium polydisulfide bispropane sulfonate (SPS): 1 mg / L, polyethylene glycol-6000: 100 mg / L, benzotriazole: 100 mg / L, 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0060] Comparative Example 7

[0061] The specific implementation is the same as that of Example 2, except that, in the copper electroplating solution, sodium poly(disulfide) propane sulfonate (SPS): 1 mg / L, polyethylene glycol-6000: 150 mg / L, benzotriazole: 50 mg / L, and 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0062] Comparative Example 8

[0063] The specific implementation method is the same as that of Example 3, except that, in the copper electroplating solution, sodium poly(dipropane disulfide) (SPS): 15 mg / L, polyethylene glycol-8000: 400 mg / L, benzotriazole: 200 mg / L, and 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0064] Comparative Example 9

[0065] The specific implementation is the same as that of Example 3, except that, in the copper electroplating solution, sodium poly(dipropane disulfide) (SPS): 10 mg / L, polyethylene glycol-8000: 400 mg / L, benzotriazole: 180 mg / L, and 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0066] Comparative Example 10

[0067] The specific implementation method is the same as that of Example 3, except that, in the copper electroplating solution, sodium poly(dipropane disulfide) (SPS): 10 mg / L, polyethylene glycol-8000: 300 mg / L, benzotriazole: 200 mg / L, and 3,3'-dimethoxybenzidine hydrochloride: 5 mg / L.

[0068] Comparative Example 11

[0069] The specific implementation is the same as that of Example 3, except that the electroplating process is: electroplating for 60 minutes at a current interval of 2 s and a current density of 3 A / dm2.

[0070] Example 4

[0071] Performance Testing

[0072] 1. Determination of coating thickness.

[0073] 2. Roughness measurement of the coating: when there are nodules, peeling, blistering, falling off and other phenomena on the coating surface, and the height of the raised part accounts for more than 20% of the total coating thickness, it is recorded as rough; when the height of the raised part accounts for more than 10% and less than 20% of the total coating thickness, it is recorded as relatively rough; when the height of the raised part accounts for less than 5% of the total coating thickness or there is no nodules, peeling, blistering, falling off and other phenomena, it is recorded as smooth.

[0074] 3. To measure the brittleness of the coating, use a metal steel ball or a spherical punch to evenly apply pressure to the sample clamped in the specified mold until the coating begins to crack, and record the pressure value when the coating cracks.

[0075] 4. Through-hole void measurement: cut the through-hole longitudinally and observe the void phenomenon in the through-hole after electroplating.

[0076] The results are shown in the following table:

[0077] Thickness / μm Roughness Brittleness / N Hollow Example 1 15 smooth 38 none Example 2 17 smooth 36 none Example 3 16 smooth 37 none Comparative Example 1 27 Rough 31 have Comparative Example 2 29 Rough 33 have Comparative Example 3 33 Rough 34 have Comparative Example 4 34 Rough 25 have Comparative Example 5 31 Rough 26 have Comparative Example 6 31 Rough 27 have Comparative Example 7 26 Rough 28 have Comparative Example 8 29 smooth 31 have Comparative Example 9 28 Rough 33 have Comparative Example 10 27 Rough 29 have Comparative Example 11 25 Rough 26 have

[0078] The method of the present invention has been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein within the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention.

Claims

1. A copper electroplating method for filling a through hole of an IC carrier, characterized in that: The following steps are involved: Step S1: spraying the IC substrate with deionized water for 5-10 minutes, and stirring, circulating and swinging at 100-200 r / min in a tank containing electroplating copper solution; Step S2: Place the substrate pretreated in step S1 in a copper electroplating solution, with the phosphor copper material as the anode and the substrate as the cathode. Direct current is applied during the electroplating process at 40-45°C, using a step-type electroplating process. In the initial stage, the current is 2.5A / dm at 2s intervals. 2 The current density is 20-30min for electroplating; in the transition stage, the current interval is 2s, 2.5-3.0A / dm 2 The current density is used for electroplating for 20-30 minutes; in the final stage, the current density is 3.0A / dm2 with a current interval of 2s, and the electroplating is carried out for 20-30 minutes; wherein the copper electroplating solution comprises the following components according to concentration: copper methanesulfonate: 190-220g / L, methanesulfonic acid: 40-60g / L, chloride ion: 30-40mg / L, sodium polydisulfide dipropane sulfonate (SPS): 1-10mg / L, polyethylene glycol: 150-300mg / L, benzotriazole: 100-180mg / L, 3,3'-dimethoxybenzidine hydrochloride: 1-10mg / L, and deionized water: the balance.

2. The copper electroplating method for filling IC carrier through-holes according to claim 1, characterized in that: In step S2, the chloride ions are provided by one or more of cupric chloride dihydrate, sodium chloride or hydrochloric acid.

3. The copper electroplating method for filling IC carrier through-holes according to claim 1, characterized in that: In step S2, the polyethylene glycol is selected from any one of polyethylene glycol-4000, polyethylene glycol-6000, polyethylene glycol-8000, and polyethylene glycol-10000, or a combination of any proportions of the above.

4. The copper electroplating method for filling IC carrier through-holes according to claim 1, characterized in that: In step S2, the current density and the electroplating time are adjusted according to the diameter and depth of the through hole of the IC substrate.