Multi-section current electroplating method for filling micro blind hole from bottom to top

Abstract

The invention relates to the technical field of electronic electroplating packaging, in particular to a multi-section current electroplating method for filling a micro blind hole from bottom to top, which comprises the following steps of: after deoiling, etching and pickling a blind hole plate, putting the blind hole plate into electroplating liquid as a cathode, performing electroplating and hole filling on the blind hole plate by adopting a constant multi-section current density after section-by-section lifting; and the current density of the first section of the multi-section current density is set to be 0.01 ASD to 0.1 ASD. According to the method, electroplating is conducted at the initial stage by adopting the small current density, the effects of filling from bottom to top and no copper deposition on the surface are achieved, and the uniformity and thickness of copper deposition can be controlled. Therefore, an extra copper layer can be prevented from being formed on the surface of the micro blind hole, and no copper deposition on the surface of the micro blind hole is ensured. And the bottom-up filling effect without surface copper growth on the surface can be achieved without preposed electrochemical testing, the technological process is simplified, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electronic electroplating packaging, and in particular to a multi-segment current electroplating method for filling micro blind holes from bottom to top. Background Art

[0002] In advanced packaging processes, electroplated copper-filled micro-blind via technology plays an important role in secondary packaging. Among them, micro-blind vias are usually used to connect electronic components at different levels or connect top-level components to bottom-level circuit boards to achieve functions such as signal transmission and power connection. Electroplated copper-filled micro-blind via technology can effectively achieve signal transmission and electrical connection between various layers, improve the density and functionality of circuit boards, achieve connection and communication between multi-layer circuit boards, and promote high-density integration and performance optimization of electronic products.

[0003] With the development of technologies such as artificial intelligence, high-order, multi-level, high-density interconnection designs are becoming increasingly common, which puts higher requirements on the electroplated copper filling micro blind hole technology, especially the ultra-thin copper filling technology. For example, Chinese patent CN115379666A discloses a blind hole filling method without surface copper deposition, but before electroplating, cyclic voltammetry test and ohmic compensation are required to determine the current density or voltage range and then perform constant voltage / constant current electroplating within the current density or voltage range. The operation process is complicated, and the voltage range obtained by the test is prone to errors.

[0004] It can be seen that in the prior art, electrochemical testing is required for electroplating of micro blind holes, which prolongs the production time and increases the cost investment, thus resulting in the defects of long process cycle and high production cost. In addition, the electrochemical test required in the prior art cannot accurately simulate the actual electroplating conditions or has errors, which may lead to instability of the subsequent electroplating process, thereby increasing the difficulty of process debugging.

[0005] Therefore, it is necessary to provide a faster and simpler blind hole filling method that can achieve surface-free copper growth and bottom-up filling effects without the need for electrochemical testing.

[0006] Through the above analysis, the problems and defects of the existing technology are as follows: the existing method suitable for thinning the surface copper thickness requires pre-electrochemical testing, which is complicated to operate and has certain errors. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a multi-stage current electroplating method for filling micro blind holes from bottom to top. The multi-stage current electroplating method for filling micro blind holes from bottom to top can achieve surface-free copper growth and bottom-up filling effect without electrochemical testing, and has the advantages of being quick and simple, simple process, short production cycle and low production cost.

[0008] In order to achieve the purpose of the above invention, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides a multi-stage current electroplating method for filling micro blind holes from bottom to top, comprising the following steps: after degreasing, etching and pickling a blind hole plate, the blind hole plate is placed in an electroplating solution as a cathode, and the blind hole plate is electroplated and filled with a multi-stage current density that is first increased step by step and then kept constant;

[0010] The first current density of the multiple current densities is set to 0.01ASD to 0.1ASD.

[0011] The present invention discloses a multi-stage current electroplating method for filling micro blind holes from bottom to top. The blind hole plate is electroplated and filled with a multi-stage current density that is first gradually increased and then constant. The current density of the first stage is set to 0.01ASD to 0.1ASD. A smaller current density is used for electroplating in the initial stage so that a starting copper layer is formed at the bottom of the micro blind hole. As the current density gradually increases, the copper deposition rate at the bottom of the micro blind hole increases, and the micro blind hole is filled from the bottom of the hole upwards, ensuring that the inside of the micro blind hole is fully filled, thereby achieving a bottom-to-top filling effect. The present invention can control the uniformity and thickness of copper deposition by gradually increasing the current density and accurately controlling the electroplating process. Therefore, it is possible to avoid the formation of an additional copper layer on the surface of the micro blind hole, thereby ensuring that there is no copper deposition on the surface of the micro blind hole.

[0012] In addition, due to the difference in mass transfer between the surface and the inside of the micro blind hole, the coverage of the inhibitor in the electroplating solution at the bottom of the micro blind hole is smaller than that on the hole surface. A small current is applied at the initial stage of electroplating, so that the inhibition layer at the bottom of the micro blind hole is first "broken down" by copper ion reduction, and the bottom of the hole is locally activated; while the inhibitor concentration on the surface of the micro blind hole is high and the coverage is large, the deposition of copper ions is still completely prevented, so no surface copper is generated on the surface of the micro blind hole.

[0013] Furthermore, the plating time of the first current density of the multiple current densities is set to 0.1s-100s. In the initial stage, a smaller current density is used for plating for 0.1s-100s to form an initial copper layer at the bottom of the micro blind hole.

[0014] Further, when the current density reaches 0.1ASD, the current density is increased by 0.02ASD to 0.1ASD in stages. When the current density reaches 0.1ASD, the current density is gradually and slowly increased. On the one hand, the copper deposition rate at the bottom of the micro blind hole can be increased, and the micro blind hole can be filled from the bottom of the hole upwards. On the other hand, the uniformity of the copper deposition in the micro blind hole can be better. The present invention increases the current density by 0.02ASD to 0.1ASD in stages, which can well achieve the filling of the micro blind hole from the bottom of the hole upwards, and the uniformity of the copper deposition in the micro blind hole is good.

[0015] Furthermore, when the current density is increased by 0.02ASD to 0.1ASD in stages and then raised to 0.3ASD to 0.5ASD, it is set to a constant current density to complete the electroplating; the present invention uses a small current density for plating in the initial stage, so that a starting copper layer is formed at the bottom of the micro blind hole, and then the current density is gradually and slowly increased to achieve the filling of the micro blind hole from the bottom of the hole upward, and the uniformity of the copper deposition in the micro blind hole is relatively good, until the current density is increased to 0.3ASD to 0.5ASD, it can be set to a constant current density to complete the electroplating. In addition, when the current density is increased to 0.3ASD to 0.5ASD, the final constant current density is determined as needed according to the size of the plated product. If the plated product is relatively large, when the current density is increased to 0.3ASD to 0.5ASD, it can be further increased to the required current density to complete the electroplating, so as to shorten the overall plating time.

[0016] and / or

[0017] The plating time of each current density before the current density increases from 0.1ASD to 0.3ASD to 0.5ASD is set to 10s to 2000s. The plating time of each current density before the current density increases from 0.1ASD to 0.5ASD is controlled to ensure that the micro blind hole is filled from the bottom of the hole upwards and to ensure the uniformity of copper deposition in the micro blind hole.

[0018] Further, when the current density reaches 0.1ASD, the current density is increased by 0.02ASD to 0.1ASD step by step to 0.3ASD to 0.5ASD, and then the current density is increased to the required current density and then constant to complete the electroplating. When the current density is increased by 0.02ASD to 0.1ASD step by step to 0.3ASD to 0.5ASD, the size of the final constant current density is determined according to the actual production needs, especially according to the size of the actual plated product and the size of the micro blind hole.

[0019] Furthermore, the electrochemical workstation is used to set a multi-stage current density that is first gradually increased and then constant to electroplate and fill the blind hole plate. The electrochemical workstation is used to set a multi-stage current density, which is convenient to set and simple to operate.

[0020] Further, the electroplating solution includes components with the following concentrations:

[0021] Copper sulfate pentahydrate 30g / L~300g / L, sulfuric acid 30g / L~300g / L, halogen ion 0.01mg / L~100mg / L, accelerator 0.1mg / L~100mg / L, inhibitor 100mg / L~600mg / L, leveler 0.1mg / L~100mg / L.

[0022] Furthermore, the degreasing is to immerse the blind hole plate in a degreasing liquid for 5s-10s; the degreasing liquid is anhydrous ethanol. By degreasing the blind hole plate, the oil stains on the surface of the blind hole plate can be well cleaned, which is convenient for better plating.

[0023] Furthermore, the etching is to immerse the blind hole plate in an etching solution formed by a combination of sodium persulfate and sulfuric acid for 5s-10s. By etching the blind hole plate, a rough surface can be formed on the surface of the blind hole plate, thereby increasing the specific surface area of ​​the blind hole plate surface, which is beneficial to the adhesion of the electroplated copper layer.

[0024] Furthermore, the pickling is to immerse the blind hole plate in sulfuric acid for 55s-65s. The pickling process can remove impurities such as oxide film, grease, rust, etc. on the surface of the blind hole plate, which is more conducive to the copper plating.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) A multi-stage current electroplating method for filling micro blind holes from bottom to top of the present invention is to electroplate and fill the blind hole plate with a multi-stage current density that is first gradually increased and then constant, and the current density of the first stage is set to 0.01ASD~0.1ASD. In the initial stage, a smaller current density is used for electroplating so that a starting copper layer is formed at the bottom of the micro blind hole. As the current density gradually increases, the copper deposition rate at the bottom of the micro blind hole increases, and the micro blind hole is filled from the bottom of the hole upwards, ensuring that the inside of the micro blind hole is fully filled, and the bottom-up filling and surface copper deposition effect are achieved. The present invention can control the uniformity and thickness of copper deposition by gradually increasing the current density and accurately controlling the electroplating process. Therefore, it is possible to avoid the formation of an additional copper layer on the surface of the micro blind hole, thereby ensuring that there is no copper deposition on the surface of the micro blind hole.

[0027] (2) The multi-stage current electroplating method for filling micro blind holes from bottom to top of the present invention can achieve surface copper growth without surface and bottom-up filling effect without the need for prior electrochemical testing, thereby simplifying the process flow and improving production efficiency. It has the advantages of being quick and simple, simple in process, short in production cycle and low in production cost.

[0028] (3) The multi-stage current electroplating method for filling micro blind holes from bottom to top of the present invention can be applied to different electroplating solution systems. The multi-stage current density electroplating method is easy to operate and control, can provide a more flexible process control space, and has a wider applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is a metallographic microscope image of a hole filling result after hole filling by multi-stage current electroplating in Example 1 of the present invention.

[0031] Figure 2 This is a metallographic microscope image of a hole filling result after hole filling by multi-stage current electroplating in Example 2 of the present invention.

[0032] Figure 3 This is a metallographic microscope image of a hole filling result after hole filling by multi-stage current electroplating in Example 3 of the present invention.

[0033] Figure 4 This is a metallographic microscope image of a hole filling result after hole filling by multi-stage current electroplating in Example 4 of the present invention.

[0034] Figure 5 This is a metallographic microscope image of a hole filling result after hole filling by multi-stage current electroplating in Example 5 of the present invention.

[0035] Figure 6 This is a metallographic microscope image of a hole filling result after multi-stage current electroplating with a current density of 0.2ASD in comparative example 1 of the present invention.

[0036] Figure 7 This is a metallographic microscope image of the hole filling result after the hole is filled with a current density of 0.2ASD in comparative example 2 of the present invention and multi-stage current electroplating with another electroplating solution.

[0037] Figure 8 This is a metallographic microscope image of a hole filling result after the electroplating hole filling is completed in comparative example 3 of the present invention at a constant current density of 0.3ASD.

[0038] Fig. 9 This is a metallographic microscope image of a hole filling result after the electroplating hole filling is completed in comparative example 4 of the present invention at a constant current density of 0.5ASD.

[0039] Fig.10 This is a metallographic microscope image of a hole-filling result after electroplating hole-filling in comparative example 5 of the present invention.

[0040] Fig.11 This is a metallographic microscope image of a hole-filling result after electroplating hole-filling in comparative example 6 of the present invention. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. In the present invention, the singular forms "a", "said" and "the" used in the embodiments and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0043] In an embodiment of the present invention, a multi-stage current electroplating method for filling micro blind vias from bottom to top includes the following steps: after degreasing, etching, and pickling a blind via plate, the blind via plate is placed in an electroplating solution as a cathode, and the blind via plate is electroplated and filled with a multi-stage current density that is first increased step by step and then kept constant;

[0044] The first current density of the multiple current densities is set to 0.01ASD to 0.1ASD.

[0045] In some embodiments, the plating time of the first current density of the multiple current densities is set to 0.1s to 100s.

[0046] In some embodiments, after the current density reaches 0.1 ASD, the current density is increased step by step by 0.02 ASD to 0.1 ASD.

[0047] In some embodiments, when the current density is increased by 0.02ASD to 0.1ASD step by step to 0.3ASD to 0.5ASD, the current density is set to a constant current density to complete the electroplating; and / or

[0048] The plating time of each current density before the current density is increased from 0.1ASD to 0.3ASD to 0.5ASD is set to 10s to 2000s.

[0049] In some embodiments, when the current density reaches 0.1 ASD, the current density is increased step by step by 0.02 ASD to 0.1 ASD to 0.3 ASD to 0.5 ASD, and then the current density is further increased to the desired current density and then kept constant to complete the electroplating.

[0050] In the embodiment, the blind hole plate is electroplated and filled by setting a multi-stage current density that is first increased step by step and then kept constant in an electrochemical workstation.

[0051] In the embodiment, the electroplating solution includes components with the following concentrations:

[0052] Copper sulfate pentahydrate 30g / L~300g / L, sulfuric acid 30g / L~300g / L, halogen ion 0.01mg / L~100mg / L, accelerator 0.1mg / L~100mg / L, inhibitor 100mg / L~600mg / L, leveler 0.1mg / L~100mg / L.

[0053] In some embodiments, the degreasing is performed by immersing the blind hole plate in a degreasing liquid for 5s-10s; the degreasing liquid is anhydrous ethanol.

[0054] In some embodiments, the etching is performed by immersing the blind hole plate in an etching solution formed by a combination of sodium persulfate and sulfuric acid for 5s-10s.

[0055] In some embodiments, the pickling is performed by immersing the blind hole plate in sulfuric acid for 55s-65s.

[0056] The following describes the invention in conjunction with specific embodiments.

[0057] Example 1

[0058] A multi-stage current electroplating method for filling micro blind holes from bottom to top comprises the following steps: immersing a blind hole plate in anhydrous ethanol, a degreasing liquid, for 8 seconds, then immersing the blind hole plate in an etching liquid formed by a combination of sodium persulfate and sulfuric acid for 8 seconds, and then immersing the blind hole plate in sulfuric acid for 60 seconds; then placing the blind hole plate in the electroplating liquid as a cathode, and placing an anode in the electroplating liquid, and electroplating the blind hole plate to fill the hole by setting a multi-stage current density that is first increased step by step and then kept constant in an electrochemical workstation.

[0059] In this embodiment, the diameter of the micro blind hole in the blind hole plate is 100 μm, and the height is 50 μm.

[0060] In this embodiment, the electroplating solution includes components with the following concentrations: 234 g / L copper sulfate pentahydrate, 50 g / L sulfuric acid, 25 mg / L chloride ions, 2 mg / L accelerator SPS, 200 mg / L inhibitor PEG-6000, and 5 mg / L leveler.

[0061] In this embodiment, the preparation method of the leveling agent is as follows: under a nitrogen atmosphere, pentaerythritol glycidyl ether and tetrahydropyrrolidine are dissolved in anhydrous ethanol to obtain a mixture, and then the mixture is stirred and reacted at 65° C. for 24 hours. After the reaction is completed, the solution is concentrated under reduced pressure to remove the ethanol solvent and unreacted tetrahydropyrrolidine, and the leveling agent can be obtained through further purification.

[0062] The chemical structure of the leveling agent is shown in Formula L1, and the leveling agent L1 is prepared via Reaction Formula I.

[0063]

[0064] In this embodiment, the multi-stage current density and plating time settings are shown in Table 1.

[0065] Table 1 Multi-stage current density and plating time parameters of Example 1

[0066] Current density / ASD Plating time / s Paragraph 1 0.1 60 Paragraph 2 0.2 60 Paragraph 3 0.3 60 Paragraph 4 0.4 60 Paragraph 5 0.5 1520

[0067] Example 2

[0068] A multi-stage current electroplating method for filling micro blind vias from bottom to top, the difference between this embodiment and embodiment 1 is that the multi-stage current density and plating time parameter settings are different. In this embodiment, the multi-stage current density and plating time settings are shown in Table 2.

[0069] Table 2 Multi-stage current density and plating time parameters of Example 2

[0070] Current density / ASD Plating time / s Paragraph 1 0.01 5 Paragraph 2 0.05 10 Paragraph 3 0.1 60 Paragraph 4 0.15 200 Paragraph 5 0.2 200 Paragraph 6 0.25 200 Paragraph 7 0.3 1260

[0071] The remaining steps and condition parameters of this embodiment are the same as those of embodiment 1.

[0072] Example 3

[0073] A multi-stage current electroplating method for filling micro blind vias from bottom to top. The difference between this embodiment and embodiment 1 is that the formula of the electroplating solution is different. In this embodiment, the electroplating solution includes the following components in concentrations: 220 g / L copper sulfate pentahydrate, 53 g / L sulfuric acid, 40 mg / L chloride ion, 2 mg / L accelerator SPS, 200 mg / L inhibitor PEG-6000, and 1 mg / L leveler.

[0074] In this embodiment, the leveling agent is a leveling agent prepared according to Chinese patent application No. 201910441505.4.

[0075] The remaining steps and condition parameters of this embodiment are the same as those of embodiment 1.

[0076] Example 4

[0077] A multi-stage current electroplating method for filling micro blind vias from bottom to top. The difference between this embodiment and embodiment 2 is that the formula of the electroplating solution is different. In this embodiment, the electroplating solution includes the following components in concentration: 220 g / L copper sulfate pentahydrate, 53 g / L sulfuric acid, 40 mg / L chloride ion, 2 mg / L accelerator SPS, 200 mg / L inhibitor PEG-6000, and 1 mg / L leveler.

[0078] In this embodiment, the leveling agent is a leveling agent prepared according to Chinese patent application No. 201910441505.4.

[0079] The remaining steps and condition parameters of this embodiment are the same as those of Embodiment 2.

[0080] Example 5

[0081] A multi-stage current electroplating method for filling micro blind vias from bottom to top, the difference between this embodiment and embodiment 4 is that the multi-stage current density and plating time parameter settings are different. In this embodiment, the multi-stage current density and plating time settings are shown in Table 3.

[0082] Table 3 Multi-stage current density and plating time parameters of Example 5

[0083] Current density / ASD Plating time / s Paragraph 1 0.05 10 Paragraph 2 0.1 60 Paragraph 3 0.2 200 Paragraph 4 0.3 200 Paragraph 5 0.4 200 Paragraph 6 0.5 1260

[0084] Example 6

[0085] A multi-stage current electroplating method for filling micro blind holes from bottom to top, the difference between this embodiment and embodiment 1 is that: after the fifth stage current density is electroplated at 0.5ASD for 60S, the current density is further increased to the required current density and then kept constant to complete the electroplating.

[0086] In this embodiment, the required current density is set according to factors such as the size of the electroplated product, the size of the micro blind vias, and actual production efficiency requirements. The required current density is increased to better shorten the overall electroplating time.

[0087] Comparative Example 1

[0088] A multi-stage current electroplating method for filling micro blind vias from bottom to top, the difference between this comparative example and Example 1 is that the current density of the first stage is 0.2ASD, and the multi-stage current density and plating time parameter settings are different. In this comparative example, the multi-stage current density and plating time settings are shown in Table 4.

[0089] Table 4 Multi-stage current density and plating time parameters of Comparative Example 1

[0090] Current density / ASD Plating time / s Paragraph 1 0.2 60 Paragraph 2 0.3 60 Paragraph 3 0.4 60 Paragraph 4 0.5 1620

[0091] The remaining steps and condition parameters of this comparative example are the same as those of Example 1.

[0092] Comparative Example 2

[0093] A multi-stage current electroplating method for filling micro blind holes from bottom to top. The difference between this comparative example and comparative example 1 is that the formula of the plating solution is different. In this comparative example, the plating solution includes the following components in concentrations: 220 g / L copper sulfate pentahydrate, 53 g / L sulfuric acid, 40 mg / L chloride ion, 2 mg / L accelerator SPS, 200 mg / L inhibitor PEG-6000, and 1 mg / L leveler.

[0094] Among them, the leveling agent is a leveling agent prepared according to the Chinese patent application with application number 201910441505.4.

[0095] The remaining steps and condition parameters of this comparative example are the same as those of comparative example 1.

[0096] Comparative Example 3

[0097] A method for filling micro blind holes by electroplating with a constant current. The difference between this comparative example and Example 3 is that this comparative example only uses a constant current electroplating to fill micro blind holes, that is, a constant current density of 0.3ASD is used to complete the electroplating filling of the micro blind holes, and the electroplating filling of the holes is performed for 30 minutes. That is, the current density and the plating time are set as shown in Table 5.

[0098] Table 5 Constant current density and plating time parameters of Comparative Example 3

[0099] Current density / ASD Plating time / s Paragraph 1 0.3 1800

[0100] Comparative Example 4

[0101] A method for filling micro blind holes by electroplating with a constant current. The difference between this comparative example and Example 3 is that this comparative example only uses a constant current electroplating to fill micro blind holes, that is, a constant current density of 0.5ASD is used to complete the electroplating filling of the micro blind holes, and the electroplating filling of the holes is performed for 30 minutes. That is, the current density and the plating time are set as shown in Table 6.

[0102] Table 6 Constant current density and plating time parameters of Comparative Example 4

[0103] Current density / ASD Plating time / s Paragraph 1 0.5 1800

[0104] Comparative Example 5

[0105] A multi-stage current electroplating method for filling micro blind vias from bottom to top, the difference between this comparative example and comparative example 2 is that the current density of the first stage is 0.15ASD, the current density of the second stage is directly increased to 0.2ASD, and the multi-stage current density and plating time parameter settings are different. In this comparative example, the multi-stage current density and plating time settings are shown in Table 7.

[0106] Table 7 Multi-stage current density and plating time parameters of comparative example 5

[0107] Current density / ASD Plating time / s Paragraph 1 0.15 60 Paragraph 2 0.2 60 Paragraph 3 0.3 60 Paragraph 4 0.4 60 Paragraph 5 0.5 1520

[0108] Comparative Example 6

[0109] A multi-stage current electroplating method for filling micro blind vias from bottom to top, the difference between this comparative example and Example 1 is that the current density of the first stage is 0.1ASD, and then the current density is increased by 0.2ASD to 0.5ASD. The multi-stage current density and plating time parameter settings are different. In this comparative example, the multi-stage current density and plating time settings are shown in Table 8.

[0110] Table 8 Multi-stage current density and plating time parameters of comparative example 6

[0111] Current density / ASD Plating time / s Paragraph 1 0.1 60 Paragraph 2 0.3 60 Paragraph 3 0.5 1620

[0112] Experimental testing

[0113] (I) Comparison of electroplating conditions in Example 1, Example 2 and Comparative Example 1

[0114] The blind hole plates electroplated in Example 1, Example 2 and Comparative Example 1 were tested for hole filling, and the micro blind holes were sliced ​​and the hole filling rate was tested using a metallographic microscope, and the presence of surface copper deposition was tested. The SEM images of the micro blind hole slices of Example 1, Example 2 and Comparative Example 1 are shown in FIG. Figure 1 , Figure 2 and Figure 6 shown.

[0115] Among them, the electroplating test results of Example 1, Example 2 and Comparative Example 1 are shown in Table 9.

[0116] Table 9 Electroplating test results of Example 1, Example 2 and Comparative Example 1

[0117]

[0118] From the electroplating test results in Table 9, it can be seen that the starting current density (i.e., the first-stage current density) of Example 1 and Example 2 are 0.1ASD and 0.01ASD, respectively, and there is no surface copper deposition. However, the starting current density (i.e., the first-stage current density) of Comparative Example 1 is 0.2ASD, and there is surface copper deposition, and the thickness of the deposited surface copper is 4.1μm. This shows that the multi-stage current electroplating hole filling in Comparative Example 1 with a current density of 0.2ASD will have surface copper deposition. This shows that the first-stage current density of the multi-stage current density of the present invention is controlled at 0.01ASD to 0.1ASD to avoid surface copper deposition.

[0119] In addition, the total electroplating time of Comparative Example 1 is longer than that of Example 1, but the hole filling rate of Comparative Example 1 is lower than that of Example 1. This indicates that controlling the first current density of the multi-stage current density at 0.01ASD to 0.1ASD can promote the improvement of the hole filling rate.

[0120] (II) Comparison of electroplating conditions of Example 3, Example 4 and Comparative Example 2

[0121] The blind hole plates electroplated in Example 3, Example 4 and Comparative Example 2 were tested for hole filling, and the micro blind holes were sliced ​​and the hole filling rate was tested using a metallographic microscope, and the presence of surface copper deposition was tested. The SEM images of the micro blind hole slices in Example 3, Example 4 and Comparative Example 2 are shown in FIG. Figure 3 , Figure 4 and Figure 7 shown.

[0122] Among them, the electroplating test results of Example 3, Example 4 and Comparative Example 2 are shown in Table 10.

[0123] Table 10 Electroplating test results of Example 3, Example 4 and Comparative Example 2

[0124]

[0125] It can be seen from the electroplating test results in Table 10 that even if another electroplating solution system is used, the starting current density (i.e., the first-stage current density) of Example 3 and Example 4 is 0.1ASD and 0.01ASD respectively, and there is no surface copper deposition. However, the starting current density (i.e., the first-stage current density) of Comparative Example 2 is 0.2ASD, and there is also surface copper deposition, and the thickness of the deposited surface copper is 3.4μm. This shows that the multi-stage current electroplating hole filling in Comparative Example 2 with a current density of 0.2ASD will have surface copper deposition. This shows that the first-stage current density of the multi-stage current density of the present invention is controlled at 0.01ASD to 0.1ASD to avoid surface copper deposition.

[0126] In addition, the total electroplating time of Comparative Example 2 is longer than that of Example 3, but the hole filling rate of Comparative Example 1 is lower than that of Example 3. This indicates that controlling the first stage current density of the multi-stage current density at 0.01ASD to 0.1ASD can promote the improvement of the hole filling rate.

[0127] (III) Comparison of electroplating conditions of Example 5, Comparative Example 3 and Comparative Example 4

[0128] The blind hole plates electroplated in Example 5, Comparative Example 3 and Comparative Example 4 were tested for hole filling, and the micro blind holes were sliced ​​and the hole filling rate was tested using a metallographic microscope, and the presence of surface copper deposition was tested. The SEM images of the micro blind hole slices of Example 5, Comparative Example 3 and Comparative Example 4 are shown in Figure 1. Figure 5 , Figure 8 and Fig. 9 shown.

[0129] Among them, the electroplating test results of Example 5, Comparative Example 3 and Comparative Example 4 are shown in Table 11.

[0130] Table 11 Electroplating test results of Example 5, Comparative Example 3 and Comparative Example 4

[0131]

[0132] From the electroplating test results in Table 11, it can be seen that both Comparative Examples 3 and Comparative Examples 4 complete the electroplating of the blind hole plate at a constant current density, wherein Comparative Example 3 completes the electroplating filling of the blind hole at a constant current density of 0.3ASD, and Comparative Example 4 completes the electroplating filling of the blind hole at a constant current density of 0.5ASD. Figure 8 and Fig. 9 It can be seen that the blind hole plates electroplated in Comparative Examples 3 and 4 both have surface copper deposition, and the surface copper deposition in Comparative Example 3 is more serious, with a surface copper thickness of 11 μm. This indicates that the electroplating of blind hole plates in Comparative Examples 3 and 4 at a constant current density will cause the problem of surface copper deposition.

[0133] In addition, comparative examples 3 and 4 complete the electroplating of the blind hole plate at a constant current density. Even though the electroplating time has reached 1800s, the hole filling rates are relatively low, being only 83.2% and 85.9% respectively.

[0134] (IV) Comparison of electroplating conditions between comparative example 5 and comparative example 6

[0135] The blind hole plates electroplated in Comparative Examples 5 and 6 were tested for hole filling, and the micro blind holes were sliced ​​and the hole filling rate was tested using a metallographic microscope, and the presence of surface copper deposition was tested. The SEM images of the micro blind hole slices of Comparative Examples 5 and 6 are shown in Figure 2. Fig.10 and Fig.11 shown.

[0136] Among them, the electroplating test results of Comparative Example 5 and Comparative Example 6 are shown in Table 12.

[0137] Table 12 Electroplating test results of Comparative Example 5 and Comparative Example 6

[0138]

[0139] From the electroplating test results in Table 12, it can be seen that in Comparative Example 5, the initial current density is increased directly from 0.15ASD to 0.2ASD in the second stage. Even if the current density is increased by 0.1ASD step by step after the second stage, copper deposition on the blind hole plate is caused. In addition, the current density of Comparative Example 6 uses 0.1ASD as the current density of the first stage, and then increases by 0.2ASD step by step, which also causes copper deposition on the blind hole plate. This shows that when the current density reaches 0.1ASD, the current density is increased by 0.1ASD step by step, which can achieve bottom-up filling of micro blind holes and avoid surface copper deposition.

[0140] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A multi-stage current electroplating method for filling micro blind vias from bottom to top, characterized in that: The following steps are involved: After degreasing, etching and pickling the blind hole plate, the blind hole plate is placed in an electroplating solution as a cathode, and the blind hole plate is electroplated and filled with holes using a multi-stage current density that is first increased step by step and then kept constant; The first current density of the multiple current densities is set to 0.01ASD to 0.1ASD.

2. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The plating time of the first current density of the multiple current densities is set to 0.1s to 100s.

3. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: When the current density reaches 0.1ASD, the current density is increased by 0.02ASD to 0.1ASD in stages.

4. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 3, characterized in that: When the current density is increased by 0.02ASD to 0.1ASD step by step to 0.3ASD to 0.5ASD, the current density is set to a constant current density to complete the electroplating; and / or The plating time of each current density before the current density is increased from 0.1ASD to 0.3ASD to 0.5ASD is set to 10s to 2000s.

5. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: When the current density reaches 0.1ASD, the current density is increased step by step by 0.02ASD to 0.1ASD to 0.3ASD to 0.5ASD, and then the current density is further increased to the required current density and then constant to complete the electroplating.

6. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The blind hole plate is electroplated and filled by setting a multi-stage current density that is first increased step by step and then kept constant on an electrochemical workstation.

7. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The plating solution includes the following components in concentrations: Copper sulfate pentahydrate 30g / L~300g / L, sulfuric acid 30g / L~300g / L, halogen ion 0.01mg / L~100mg / L, accelerator 0.1mg / L~100mg / L, inhibitor 100mg / L~600mg / L, leveler 0.1mg / L~100mg / L.

8. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The degreasing process is to immerse the blind hole plate in a degreasing liquid for 5s-10s; the degreasing liquid is anhydrous ethanol.

9. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The etching is performed by immersing the blind hole plate in an etching solution formed by a combination of sodium persulfate and sulfuric acid for 5s-10s.

10. A multi-stage current electroplating method for filling micro blind vias from bottom to top as claimed in claim 1, characterized in that: The pickling is performed by immersing the blind hole plate in sulfuric acid for 55s-65s.

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