TW201305395A - Micropore-stuffed copper electroplating system, electroplating solution, and aperture-filling formulation - Google Patents

Abstract

A micropore-stuffed copper electroplating system comprises: at least a copper ion source; at least an insoluble anode; and an electroplating solution with copper sulfate as the main ingredient, wherein the electroplating solution comprises an inhibitor and an accelerator; the accelerator is a compound containing a thioether functional group Cm-S-Cn and a reactive compound with structure formula of X-S-Y; wherein S is the above-mentioned thioether functional group, X is a compound containing a sulfonyl hydroxide group or sulfonic acid, Y is a nitrogen-containing compound; the -S-Y structure further comprises therein a C=S bond, wherein Y is the accelerator containing the above-mentioned thioether functional group generated by participating in the oxidation reaction of the insoluble anode through electrolytic operation, while S in the C=S bond is converted into sulfonate under the oxidation reaction; the electroplating system performs the electroplating copper stuffing of the micro-through-holes or ditches of a semiconductor wafer.

Description

Microporous filled copper plating system, plating solution, and hole filling formula

The present invention relates to a copper plating fill of fine vias or trenches on a semiconductor wafer in a plating system using an electrolyte containing a thioether functional group in an insoluble anode.

In terms of electroplating technology, electroplated anodes can be classified into soluble anodes and insoluble anodes (size-stabilized anodes) depending on their solubility properties. The traditional soluble anode is a titanium basket with phosphor bronze balls, and the number of titanium baskets is up to a dozen on one side. In the electroplating process, the shape of the phosphorous copper ball dissociates from the copper ions to change the shape to produce different current distributions, so that the electric field distribution is uneven, which affects the uniformity of electroplating. Since the dissolution rate of the phosphor bronze balls in the titanium basket is different, the copper ion concentration of the plating solution between the anodes is not uniform. The concentration near the anode is higher than the concentration near the cathode, and high flow circulation is required to reduce the difference in concentration and increase the uniformity of plating. In addition, the copper copper ball will produce copper chips during the dissolution process, and the wire must be stopped at intervals, and the plating solution is replaced to remove the copper chips.

Another type of insoluble anodizing is generally characterized in that cerium oxide is plated with an insoluble anode by a titanium plate or a titanium mesh, and copper ions are supplied from a copper ion dissolving tank outside the plating tank. The anode itself does not participate in the dissolution of the metal, and its effect only controls the distribution of current on the surface of the cathode. The anode size is stable, and the electric field distribution between the cathode and the anode is uniform; the plating solution is dissolved and circulated from the plating tank to the plating tank, and the concentration of each component is uniform; the current density of the electroplating operation is high, which is more than twice that of the soluble anode, and the plating capacity can be increased. The plating effect of high aspect ratio and blind buried hole is better than that of soluble anode plating.

In order to achieve a good hole filling effect, it is necessary to add an appropriate additive to the plating bath of the plating bath using the insoluble anode. The additives are classified into inorganic additives and organic additives. Inorganic additives are further divided into hydrogen ions and chloride ions, and organic additives are classified into Accelerator or Brightener, Suppressor and Leveler. Further relevant to the present invention relates to the accelerator.

Accelerators are generally mainly based on thiol-based compounds because of the effect of accelerating the reduction rate of copper ions and imparting gloss to the coating. The most commonly used copper accelerators today are SPS (Bis(3-Sulfopropy) Disulfide, sodium polydithiodipropane sulfonate) and MPS (3-mercapto-1-propanesulfonate, sodium 3-mercapto-1-propane sulfonate) . However, when SPS and MPS are applied to insoluble anodes, there will be problems of rapid consumption and cracking, mainly because the insoluble anodes are electrolyzed during electroplating, resulting in an oxygen evolution reaction, resulting in the generation of free radicals of oxygen or oxygen, thereby accelerating the cracking of the additives. And consumption. Furthermore, the increased concentration of organic matter after cracking will affect the crystal structure of the plating plate and the uniformity and ductility of the plating layer, and when the organic matter after cracking rises to a certain extent, the plating solution must be replaced, resulting in an increase in cost. , production capacity is reduced. On the other hand, when some impurities are present in the plating solution, for example, when copper is dissolved, if impurities such as iron, manganese, lead, antimony or bismuth contained in the raw material are directly contacted with the insoluble anode, a high current region is generated on the surface of the anode. Causes anode passivation and reduces its service life.

In addition to the above-mentioned additive problems, when the micro-blind hole filling of a semiconductor is performed using an insoluble anode plating system, the problem of the filling effect is almost the same as that of the soluble anodizing system. Because the filling deposition mode will be different depending on the conditions of the plating operation. It can be roughly divided into three modes: Conformal, Subconformal, and Super-filling. The uniform growth type is in the electroplating process, and the growth rate of the electroplated copper at the inner wall of the hole and the plate surface is the same, but as the electroplating time increases, a seam is easily formed in the hole. The semi-uniform growth type is because the deposition rate of the orifice is faster. As the plating time increases, the orifice is sealed in advance to form a hollow hole. Whether it is a uniform growth or semi-uniform growth type of hole filling mode, it will have a negative impact on semiconductor wafer micropore filling. Preferably, an improved plating operation environment is provided, the deposition speed of the bottom of the hole is accelerated, and the deposition speed of the plate surface is slowed down, which can cause a Bottom-Up deposition mode to achieve a high-filling type. The goal.

The purpose of the present invention is to provide a microporous filled electroplating copper system using an insoluble anode (size-stabilized anode), and a specific compound is used as an additive in the plating solution to perform fine through-holes on the semiconductor structure ( High-width-to-depth (through-hole) or copper plating of the trench, and the filling mode is Bottom-Up high-filling mode.

The specific compound described above refers to a compound containing a thioether functional group [C _m -SC _n ] which participates in the oxidation reaction of an insoluble anode during electroplating and produces a structural change which is converted into a thiol bond and a sulfonate group. Active substance. A plating solution comprising the thioether functional compound forms a two-stage active polarization on the surface of the cathode during the electroplating operation. That is, the compound containing a thioether functional group adsorbs on the surface of the cathode to form a first active polarization, trapping copper ions, and accelerating deposition of copper ions on the surface of the cathode; thereafter, the thioether functional compound is converted into an active material to continue Adsorption to the surface of the cathode forms a second active polarization, which still has the effect of capturing copper ions and accelerating copper ion deposition. It has been experimentally proven that the active material is produced only in the electroplating system of the insoluble anode and does not occur in the electroplating system of the soluble anode. The accelerated performance of this two-stage active polarization is derived from the cost-effectiveness of extending the operating time of the bath.

Described by a chemical formula [XSY] wherein S is a thioether functional group [C _m -SC _n ] described above, X is a compound containing a sulfonic acid group or a sulfonic acid, and Y is a nitrogen-containing organic compound; The -SY] structure further comprises a C=S bond; wherein both X and Y are generated in the oxidation reaction of the insoluble anode in the electrolysis operation, and the S in the C=S bond is converted to the sulfonate under the oxidation reaction. .

A more detailed chemical structural formula is as shown in Formula 1, Formula 2.

Wherein X is a compound comprising a sulfonic acid group or a sulfonic acid, including but not limited to sodium ethyl sulfonate.

Y is a nitrogen-containing organic compound including, but not limited to, dimethylamine, a functional group having a tertiary amine, and a functional group having a quaternary amine.

m is an integer from 1 to 10, and n is an integer from 1 to 3.

In the oxidation reaction of the insoluble anode and the acidic plating solution, the NC=S of the formula 1 undergoes tautomerization, the S on the bond is converted into a thiol molecule, and then oxidized to a sulfonate to form a pull electron on the surface of the cathode. Effect, increasing copper ion capture ability. Based on the above, a plating solution containing a thioether functional group C _m -SC _n and a reactive compound containing a structural compound of the structural formula XSY is applied to an insoluble anodizing system, and the above object can be achieved.

Compatible accelerators may be selected from sodium dimethylthiohydroformylpropane sulfonate (DPS), sodium 3-benzothiazol-2-indole-propane sulfonate (ZPS), and thiourea propyl sulfate. (UPS). The concentration used is 0.4umol/L~1mmol/L.

Since the insoluble anode does not precipitate copper ions during the plating process, in order to maintain the concentration of copper ions in the plating solution, an additional copper salt is required. The copper salt used includes, but is not limited to, copper oxide or copper carbonate.

The plating solution used includes, but is not limited to, a copper sulfate plating solution, but this is preferred.

The insoluble anode used comprises a metal oxide modified electrode or a platinum electrode.

Based on the above, the present invention further relates to a hole-filling formula in which a fine through-hole (high-width-to-depth ratio through-hole) or a copper deposit in a trench is filled in a copper-plated system of an insoluble anode to realize a filling mode. It is a high-filling mode of Bottom-Up.

The pore-filling formulation comprises a chloride ion, a polymer type leveling agent, a wetting agent, and an accelerator, wherein the accelerator is a compound having the above characteristics, wherein the accelerator is selected from the group consisting of dimethylthiohydrogen formazan. Sodium propane sulfonate (DPS), sodium 3-benzothiazol-2-indole-propane sulfonate (ZPS), and thiourea propyl sulfate (UPS) are preferred; the polymeric leveling agent is polymerized Vinyl pyrrolidone (PVP) is preferred; the wetting agent is selected from the group consisting of polyethylene glycol (PEG).

In order to confirm the purpose and efficacy of the above-mentioned [invention], the following experiment was carried out. In the experiment, the anode system was set as an insoluble anode, and the stability of the anode of different materials, several different accelerator active polarization manifestations, and the hole-filling formula hole-filling efficiency were analyzed.

<<Insoluble anode (or size stability anode)>>

In the experiment of the present invention, a commercialized and improved dimensionally stable anode was provided by Weiss Corporation, and IrO ₂ , DT3 and DT5 were respectively designated as codes. The size is 15 cm x 6 cm.

IrO ₂ is a metal oxide layer coated with ruthenium oxide on a Ti substrate, and the main components are Ti, O, and Ir.

The electrode components of DT3 and DT5 mainly contain Ti, Ta, O and trace Ir. It is based on Ti and covers the surface of Ir oxide and Ta oxide composite coating.

<<Additives>>

The stability of the anode based on the size stability will cause the cracking of the additive. To achieve good yield and stable bath quality, and to avoid the acceleration or cracking of the additive without reaching the pores of the cathode object, the acceleration of the additive is adopted. And the resistance is used as the qualification condition.

The five accelerators were respectively compared with SPS (sodium polydithiodipropane sulfonate), MPS (sodium 3-mercapto-1-propane sulfonate), and DPS (N, N-dimethyl). Sodium bis(dithiocarbonylpropane sulfonate), ZPS (sodium 3-(benzothiazole-2-indenyl)-propane sulfonate), UPS (thiourea propyl sulfate). Among them, SPS and MPS are the most commonly used accelerators for copper hole-filling plating in the industry, while DPS, ZPS and UPS are used industrially as brighteners for acid copper plating. The additives in this experiment also include the inhibitors Cl ^- and PEG commonly used in electroplating systems.

<<Electrical plating experiment in Haring Cell>>

Test tank conditions: DT5 is used as the anode, the basic plating solution is 0.88M CuSO ₄ and 0.54M H ₂ SO ₄ , the current density is 18ASF, the concentration of the above five accelerators is 0.085 μM, and the concentration of inhibitor Cl ^- is 1.7 μM, the concentration of PEG was 0.025 μM. The operation time is 10,000 seconds.

<<The chronopotentiometry analysis of the performance of five accelerators>>

In the first figure, the SPS is about 2000 seconds, and the SPS has a tendency to crack. At 7000 seconds, the SPS has been consistent with the curve of only PEG and Cl ^- , and it can be speculated that SPS no longer has acceleration properties. In addition, MPS at the same volume of molar concentration, although having the most accelerated activity at the beginning, also started to have polarization at about 2000 seconds, and no acceleration property was obtained in about 8000 seconds. The acceleration properties of UPS and ZPS are not obvious at the same volume of molar concentration. Although the initial acceleration activity of DPS is not as strong as SPS and MPS, after 10,000 seconds of operation, not only does the cracking occur, but the depolarization effect is obtained.

<<DPS Timing Potential Analysis of Different Anode Materials>>

As shown in the second figure, the accelerated performance of DPS in the use of phosphorous-copper soluble cations and other dimensionally stable anodes. In the IrO ₂ system, DPS has a strong accelerating property at first, but about 5,000 seconds, the potential drops, and it is speculated that some additives with accelerated properties may be cracked. In the DT5 and DT3 systems, there is a strong acceleration property, and until the end of the operation, no cracking occurs, but the depolarization effect. In the phosphor bronze system, the strong acceleration properties disappear, indicating that DPS does not exhibit strong acceleration properties in the phosphor bronze system.

<<DPS active substance>>

In the analysis of the above electroplating additives, it was found that DPS has a two-stage depolarization performance on a metal oxide modified anode or a platinum anode. From the constant current analysis curve, it is seen that the initial DPS is accelerated, but after a period of time, the curve is flat, which is supposed to be a transitional situation in which DPS is gradually consumed by the high potential and converted into another active substance, and the activity is active. The substance is more accelerated, thus causing an acceleration curve for the second stage. When the lowest potential is reached, it represents the largest amount of active material.

As for the active material, the following results were obtained by electrochemical cyclic voltammetry, UV, IR, XPS and the like.

[Electrochemical analysis]

In order to judge whether DPS will participate in the electrochemical reaction, it is scanned by cyclic voltammetry to observe whether an electrochemical reaction occurs as the potential increases and decreases. The electrochemical system uses 0.5 M H ₂ SO ₄ as the electrolyte, the working electrode is the platinum electrode and DT5, the counter electrode is a platinum plate, and the reference electrode is a mercury sulfate electrode (SMSE). The third and fourth figures respectively use the platinum electrode and DT5, and the DPS is added with 1 ppm, 5 ppm, and 10 ppm, respectively, and the scanning rate is 10 mv/s. It can be found that there is an oxidation peak in the platinum electrode and the DT5 anode system. The higher the DPS concentration, the larger the oxidation peak area, and the verification that the DPS will participate in the oxidation reaction of the dimensionally stable anode.

Further, the gold electrodes were respectively immersed in an electroless plating solution, a plating solution for 1000 seconds of electrolysis, a plating solution for 6,000 seconds of electrolysis, and a plating solution for 9000 seconds of electrolysis for 20 minutes, and then subjected to cyclic voltammetry scanning. As a result, as in the fifth and sixth figures, there was no reduction current peak (α peak) in the electroless plating solution and the plating solution for 1000 seconds of electrolysis. At the time when the electrolyte solution is most activated, a reduction current peak (α peak) appears, as shown in the seventh and eighth figures.

The above-mentioned reduction current peak (α peak) represents that the above-mentioned active material can be molecularly self-assembled on gold, which is a reasonable inference based on the literature 1.

Conclusion: It was confirmed that DPS participates in the electrochemical oxidation reaction at the anode position and proves to have a functional group which can accelerate copper deposition.

[UV analysis]

In order to determine whether there is a structural difference between DPS after electrolysis and before electrolysis, UV detection is performed. The ninth graph is a comparison of UV spectra of DPS, DPS + 3% H ₂ SO ₄ , DPS + 3% H ₂ SO ₄ (after electrolysis). The original absorption peak of DPS is about 222 nm, 254 nm and 273 nm, and an absorption peak is generated at 193 nm when sulfuric acid is added. The electrolyzed DPS has a shoulder at 210 nm, and the absorption decreases at 254 nm and 273 nm. It is speculated that DPS may be consumed by electrolysis. According to the literature 2, when nitrogen, sulfur and other heteroatoms have unbonded electrons, electrons may occur n→→ Transfer, while weak absorption occurs in the near-infrared region for compounds such as sulfur, disulfide, and mercaptans. Based on the literature 2, it is speculated that the DPS after electrolysis may contain mercaptans or other sulfur- or nitrogen-containing structures, which are determined to be different from the original structure of DPS.

Conclusion: The molecular structure of the active substances converted from DPS changes.

[IR analysis]

From the UV spectrum, it is known that DPS undergoes structural changes after electrolysis, and is further analyzed by IR to determine the structure of the active material produced. The tenth graph is a map of IR detection using a tablet of potassium bromide mixed with DPS powder.

The method for measuring an active material is a method in which a molecular self-assembly method is applied to a gold substrate to coat a single molecule film, and then measured by ATR-FTIR. The monomolecular film is prepared by electrolyzing a solution containing DPS to a time point at which the amount of active material generated is maximized, and then immersing the gold substrate in the solution to self-assemble the active material on the gold substrate to form a monomolecular film.

Table 1 and Table 2 are the IR spectra of the active materials after analysis of DPS and electrolysis, respectively, and the difference between the two is compared. It is presumed that the active material also has a -CH ₃ terminal functional group, a CN bond, and a sulfonate group.

Conclusion: DPS after electrolysis is easy to perform molecular self-assembly on gold. The active substance formed has thiol bond, and more copper-capturing functional groups make copper deposition faster (acceleration).

[XPS analysis]

Using a gold piece as a substrate, and performing long-term molecular self-assembly in a plating solution having electrolysis and electrolessness, the molecular structure change on the surface of the gold piece was further analyzed by XPS. The eleventh and twelfth figures are the XPS total energy spectra of the molecular self-assembly in the electroless and post-electrolytic plating solution, respectively. Comparing the element content of the two, the content of S and N is higher on the gold self-assembled gold plate in the plating solution after electrolysis, which may be caused by the large amount of active substances adsorbed by DPS adsorbed on gold, just to verify In the foregoing electrochemical analysis structure, the active material converted by DPS has the ability of molecular self-assembly. If the S 2p single element energy spectrum (Fig. 13) is compared, (A) is the molecular self-assembly in the electrolytic plating solution for molecular self-assembly (B) in the electroless plating solution. It can be found that the DPS after electrolysis has changed in structure, and a strong signal is added at the position of 168.4 eV, which may be accompanied by S oxide, which may be assumed to be a sulfonate.

Conclusion: From the combined literature and the above analysis of the active substances, it is speculated that under the acidic copper system using a size-stabilized anode, the double-bonded S atoms on DPS are converted to mercaptans via tautomerization and acid catalysis. Molecules, in the high oxidation state, the thiol molecules are sequentially oxidized to sulfonate, so there is a large sulfonate signal generated in the XPS analysis results. As shown in the fourteenth figure.

<<filling formula>>

At present, the 3D package is still based on the direct hole-filling process, which can achieve superfilling and the board surface is not long copper.

At present, there are not many experiments and applications in the academic and industrial aspects of the dimensional stability anode application in the enamel wafer hole-filling plating, partly because the dimensional stability anode and the hole-filling additive are difficult to achieve a perfect match, which is easy to cause the bath liquid. Deterioration affects the ability to fill holes. Thus, the present invention develops a novel pore-filling formulation with a dimensionally stable anode in combination with suitable additives.

According to the literature 4, DPS is a composite additive, and its inhibition ability is higher than that of acceleration at a high concentration, so it is accelerated at a low concentration. From the above electrochemical analysis results, even at very low concentrations, the accelerated activity of DPS is still very strong. If PEG (polyethylene glycol) and Cl ^{- are} used for pore filling, copper grows almost near the surface and the pores. As the aperture is reduced, the more there is a tendency to seal. As Annex I

Document 5 stated, PVP can eliminate leveling agent to generate the bump plate surface, electrochemical behavior and PEG-Cl ^- Similarly, if while adding PEG and PVP (polyvinyl pyrrolidone), PVP can be substituted PEG-Cl ^- on the plate occupies With a strong inhibitory effect.

1. Based on Document 5, the present invention employs polyvinylpyrrolidone (PVP) having a molecular weight of from 2,000 to 200,000. The polymer chain and the nitrogen-containing heterocycle can effectively inhibit the copper deposition rate of the plate surface and the orifice. As in Annex II, using 0.9ppm DPS, 60ppm Cl ^- , and 2ppm of high-molecular leveling agent PVP (29000) and 50ppm of polyethylene glycol PEG (400) without adding large molecular weight inhibitors Wet agent as an additive. The results show that a good filling effect can be achieved without voids and crevices.

When filling a hole with a PVP having a molecular weight of 29000, the top of the hole is raised in a V-type mode. If the PVP with a molecular weight of 10,000 is changed to fill the pores, the composition of the additive is similar to that of the previous section, and only PVP (29000) is changed to PVP (10000) of the same volume molar concentration. As a result, as shown in Annex III, the hole filling mode is slightly different from PVP (29000), and the hole is moved up in a flat manner.

Document 1, W. P. Dow, Y. D. Chiu, and M. Y. Yen, "Microvia Filling by Cu electroplating Over a Au Seed Layer Modified by a Disulfide", J. Electrochem. Soc., 156, D155, 2009.

Document 2, You Ruicheng, "Organic Spectroscopy", a large library of scientific books, 81 years.

Document 3, J. F. Moulder, W. F. Stickle, P. E. Sobol, and K. D. Bomben, "Handbook of X-ray Photoelectron Spectroscopy", 1992.

Document 4, S.K. Cho, S.K. Kim, and J.J. Kim, "Superconformal Cu Electrodeposition Using DPS A Substitutive Accelerator for Bis (3-sulfopropyl) Disulfide", J. Electrochem. Soc., 5, C330, 2005

Document 5, M. J. Willey, J. Reid, and A. C. West, "Adsorption Kinetics of Polyvinylpyrrolidone during Copper Electrodepostion", Electrochem, Solid-State Lett., 10, D38, 2007.

The first figure shows the chronopotentiometric analysis of different accelerators.

The second figure shows the chronopotentiometric analysis of different anode materials.

Figure 3, Cyclic voltammograms for different DPS concentrations.

Figure 4, Cyclic voltammograms for different DPS concentrations.

In the fifth graph, the results of the cyclic voltammetry scan of the gold electrode self-assembled by the molecule (unelectrolyzed operation).

In the sixth graph, a cyclic voltammogram of a cyclic voltammetric scan with a gold electrode of SAM (electrolytic operation for 1000 s).

In the seventh graph, a cyclic voltammogram (electrolytic operation 6000s) of cyclic voltammetry scanning with a SAM gold electrode was performed.

In the eighth graph, a cyclic voltammogram (electrolytic operation 9000s) of cyclic voltammetry scanning with a SAM gold electrode was performed.

Figure IX, UV spectrum of DPS.

Figure 10, IR spectrum of DPS.

Figure 11 shows the XPS pluripotency spectrum of a gold piece self-assembled in an electroless plating bath.

Figure 12 shows the XPS pluripotency spectrum of a gold piece self-assembled in an electrolytic plating bath.

The thirteenth picture, the gold substrate S2P energy spectrum.

Figure 14. DPS produces a speculative map of the active substance.

Annex I, a sliced view of the hole-filling results of DT5 in TSV.

Attachment 2, a sliced view of the hole-filling results of DT5 in TSV.

Annex III, a sliced view of the hole-filling results of DT5 in TSV.

Claims (15)

A microporous filled electroplating copper system comprising at least one source of copper ions; at least one insoluble anode; and a plating solution having a main component of copper sulfate, the electroplating solution containing an inhibitor and an accelerator; the accelerator having a thioether function a compound of the group C _m -SC _n and a reactive compound comprising a structure of the formula XSY; wherein, S is a thioether functional group as described above, X is a compound containing a sulfonic acid group or a sulfonic acid, and Y is a nitrogen-containing organic compound; The [-SY] structure further comprises a C=S bond; wherein Y is an accelerator containing the above thioether functional group generated by an electrolytic operation participating in the oxidation reaction of the insoluble anode, and C=S bond S is under the oxidation reaction Conversion to sulfonate; the plating system performs copper plating in the fine vias or trenches of the semiconductor wafer. The microporous-filled electroplating copper system according to claim 1, wherein the Y structural formula is a tertiary amine. The microporous-filled electroplated copper system according to claim 1, wherein the Y structural formula is a quaternary amine. The microporous-filled electroplating copper system according to claim 1, wherein the Y structural formula is dimethylamine. The micro-hole filled electroplated copper system according to claim 1, wherein m is an integer of 1 to 10, and n is an integer of 1 to 3. The microporous-filled electroplating copper system according to claim 1, wherein the accelerator is selected from the group consisting of sodium dimethylthiohydroformylpropane sulfonate (DPS) and 3-benzothiazole-2. - Sodium decyl-propane sulfonate (ZPS), and thiourea propyl sulfate (UPS). The microporous-filled electroplating copper system according to claim 1, wherein the accelerator concentration is 0.4 umol/L to 1 mmol/L. The microporous-filled electroplating copper system according to claim 1, wherein the inhibitor is selected from the group consisting of polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG). The microporous-filled electroplated copper system according to claim 1, wherein the dimensionally stable anode is a metal oxide modified electrode or a platinum electrode. A plating solution for an insoluble anodized copper system for microporous filling, characterized in that: the main component is a copper sulphate plating solution, the plating solution contains an inhibitor and an accelerator; and the accelerator contains a thioether functional group C _a compound of _m -SC _n and a reactive compound comprising a structural formula XSY; wherein, S is a thioether functional group as described above, X is a compound containing a sulfonic acid group or a sulfonic acid, and Y is a nitrogen-containing organic compound; The structure further comprises a C=S bond; wherein Y is an accelerator containing the above thioether functional group generated by an electrolytic operation to participate in the oxidation reaction of the insoluble anode, and the C=S bond S is converted into a sulfonate under the oxidation reaction. . A micropore filling formulation suitable for an insoluble anodizing copper system, comprising: a chloride ion, a polymer leveling agent, a wetting agent, and an accelerator, the accelerator being a compound containing a thioether functional group C _m -SC _n and A reactive compound comprising a structural XSY structure; the accelerator is subjected to an electrolytic operation to participate in an oxidation reaction of an insoluble anode to produce a sulfonate. The micropore-filled microporous filling formulation according to claim 11, wherein the accelerator is selected from the group consisting of sodium dimethylthiohydroformylpropane sulfonate (DPS) and 3-benzothiazole- Sodium 2-mercapto-propane sulfonate (ZPS), and thiourea propyl sulfate (UPS). The micropore-filled micropore filling formulation according to claim 11, wherein the polymer type leveling agent is polyvinylpyrrolidone (PVP). The micropore-filled microporous filling formulation according to claim 13, wherein the polyvinylpyrrolidone (PVP) has a molecular weight of from 2,000 to 200,000. The microporous filled microporous filling formulation according to claim 11, wherein the wetting agent is polyethylene glycol (PEG) having a molecular weight of 400-6000.