TWI638912B - Copper electroplating solution, method for copper electroplating and method for forming copper pillars - Google Patents

Abstract

The present invention relates to a copper plating bath, a method of electroplating copper, and a method of forming a copper pillar. The copper plating bath is characterized by using polyethylene glycol having a molecular weight of 20,000 as an inhibitor and optimizing the concentration of polyethylene glycol and dithiodipropane sulfonate. When electroplating is performed using the copper plating solution, a bright mirror-like copper film layer can be formed on the substrate at a high current density. Similarly, when the copper plating solution is formed on the substrate by the copper plating solution, the quality of the copper column can be improved.

Description

Copper plating solution, method of electroplating copper and method of forming copper pillar

The present invention relates to a plating solution, and more particularly to a copper plating solution, a method of performing copper plating using the copper plating solution, and a method of forming a copper pillar on a substrate using the copper plating solution.

Electroplated copper technology is widely used to fabricate ultra-large-scale integration (ULSI) semiconductor devices and copper columns or traces of printed circuit boards (PCBs).

Traditional multilayer PCBs are limited by their package density and do not meet the trend of advanced products. In order to increase the packing density, a high-density interconnection (HDI) design using microbumps to connect two conductive layers is indispensable. In recent years, since copper pillars have superior performance in terms of good pitch, fine pitch capability, and low electrical resistance, copper pillars are formed by electroplating copper and have attracted considerable attention as a connecting material.

Copper plating baths for dual damascene processes typically contain CuSO ₄ , H ₂ SO ₄ , Cl ^- ions, and various types of organic additives to achieve perfect fill deposition of copper for high aspect ratio vias. Conventional organic additives commonly used to accomplish "superfilling" include inhibitors, accelerators, and leveling agents.

Polyethylene glycol (PEG) having a molecular weight of between 4,000 and 8,000 is a surfactant generally used as an inhibitor. Many studies have reported that the inhibitory effect of PEG is significantly increased in the presence of Cl ^- ion, which is mainly related to the synergy between Cu ⁺ , PEG and Cl ^- . The use of PEG with a small molecular weight mainly moves faster in solution and has a high quality transfer effect, so that Cu ^{+ is} quickly carried to the electrode to generate an electroplating reaction. Typical accelerators include 3-mercapto-1-propanesulfonate (MPS) or bis(3-sulfopropyl) disulfide (SPS). Accelerators can be changed. The charge transfer process at the surface, in turn, increases the rate of copper deposition. A leveling agent, such as Janus Green B (JGB) or benzotriazole having a nitrogen-containing aromatic ring functional group, is used to increase overpotential and inhibit copper deposition.

Further, when a copper pillar is formed by electroplating, the copper pillar having a flat top can significantly reduce the time of chemical mechanical polishing (CMP), thereby reducing the manufacturing cost and contributing to the yield of the back end product. However, the prior art has attempted the effect of different additives for forming copper pillars, but the suitable concentration that can be used for industrial production is still unclear. In addition, if a high current density is applied to increase the plating rate, the formed copper pillar usually has a slope or a pit at the top thereof, and grows an uncontrollable nodule.

In order to obtain a flat top copper pillar and prevent the growth of nodules, the conventional method generally gradually increases the current density of the electroplated copper step by step. However, this method will increase the plating time.

Further, in the prior art, there has not been a related literature that reduces the copper crystal grain to improve the plating effect.

It is an object of the present invention to provide a copper plating solution, a method of electroplating copper, and a method of forming a copper pillar. Compared with the conventional copper plating solution, the present invention can have good plating quality even at an increased current density. That is, it is possible to suppress the occurrence of the nodules on the surface of the copper while shortening the plating time.

Another object of the present invention is to provide a copper plating solution, a method of electroplating copper, and a method of forming a copper pillar, which can improve the surface topography of copper.

It is still another object of the present invention to provide a copper plating solution, a method of electroplating copper, and a method of forming a copper pillar, which can control the size of the copper crystal grains formed by electroplating to further improve the quality of electroplating.

According to an embodiment of the present invention, the copper plating solution comprises a substance composition of 1.2×10 ⁵ to 1.8×10 ⁵ ppm of copper sulfate pentahydrate, 9.8×10 ⁴ to 1.372×10 ⁵ ppm of sulfuric acid, and 50 to 70 ppm of chlorine. Ionic, 3-12 ppm dithiodipropane sulfonate, 240-780 ppm polyethylene glycol, and Jianna Green B, wherein the polyethylene glycol has a molecular weight of 20,000, and the Jianna green B: The concentration ratio of polyethylene glycol is 1:40000.

Preferably, the concentration of the dithiodipropane sulfonate is further from 6 to 12 ppm.

Preferably, the concentration of the polyethylene glycol is further from 420 to 600 ppm.

According to another embodiment of the present invention, a method of electroplating copper includes: providing a substrate as a working electrode and providing a pair of electrodes, the working electrode and the pair of electrodes being immersed in a copper plating solution; the working electrode And applying a constant current to the pair of electrodes, the copper plating solution is disturbed during the application of the constant current, wherein the copper plating solution used is the copper plating solution described above.

Preferably, the material of the substrate comprises copper.

Preferably, the constant current has a current density of 5 A·dm ^-2 to 9 A·dm ^-2 .

Preferably, the current density of the constant current is 7.5 A·dm ^-2 or less.

Preferably, the disturbance rate of disturbing the copper plating solution is 150 rpm or less.

Preferably, the disturbing flow direction generated by the copper plating solution is at an angle of 10 to 80 degrees with the surface of the working electrode.

According to still another embodiment of the present invention, a method of forming a copper pillar includes: providing a substrate as a working electrode and providing a pair of electrodes, the working electrode and the pair of electrodes being immersed in a copper plating solution, wherein the substrate Forming a mask having a through hole; applying a constant current to the working electrode and the pair of electrodes to deposit copper in the through hole, disturbing the copper plating solution during application of the constant current; and removing the A mask is formed thereby forming a copper pillar on the substrate, wherein the copper plating solution used is the copper plating solution described above.

Hereinafter, a method of electroplating copper of the present invention will be described with reference to FIG.

First, a step S101 of providing a copper plating solution is performed. The components in the copper plating bath may comprise copper sulfate pentahydrate (CuSO ₄ ·5H ₂ O, such as from Sigma-Aldrich), sulfuric acid (H ₂ SO ₄ , such as from Merck), chloride ion (Cl ^- , The ions are supplied by hydrochloric acid (HCl), for example, from Merck, dithiodipropane sulfonate (SPS, for example, from Carbosynth), polyethylene glycol (PEG, for example, from Alfa Aesar), and Jianna. Green B (JGB, for example, purchased from Alfa Aesar).

The concentration of CuSO ₄ ·5H ₂ O may be not limited as needed, but the concentration is preferably from 1.2 × 10 ⁵ to 1.8 × 10 ⁵ ppm. The concentration of H ₂ SO ₄ may be not limited as needed, but the concentration is preferably 9.8 × 10 ⁴ to 1.372 × 10 ⁵ ppm. The concentration of Cl ^- may be unlimited as needed, but the concentration is preferably from 50 to 70 ppm.

As the accelerator, the concentration of SPS may be 3 to 12 ppm, preferably 6 to 12 ppm, more preferably 6 to 9 ppm. As an inhibitor, PEG may have a molecular weight of 20,000 (i.e., PEG 20000). The concentration of PEG 20000 may range from 240 to 780 ppm, preferably from 420 to 780 ppm, more preferably from 420 to 600 ppm. As the leveling agent, as long as the concentration ratio of JBG:PEG is 1:40000, the JGB may be a concentration as needed.

The concentrations indicated above are the concentrations of the substance in the copper plating bath.

Next, in step S102, a substrate is provided as a working electrode and a counter electrode is provided, and then the working electrode and the counter electrode are immersed in a copper plating solution of the electroplating apparatus.

As the substrate of the working electrode, for example, bulk copper (purity: 99%, 50 mm × 50 mm × 1.5 mm) which is polished with tantalum carbide (SiC) sandpaper and cleaned with deionized (DI) water, For the counter electrode, a platinum (Pt) coil can be used. In the electroplating apparatus, the distance between the working electrode and the counter electrode from each other can be unrestricted as needed, for example, the distance can be 2.5 cm.

Next, in step S103, a constant current is applied to the working electrode and the counter electrode, and the copper plating solution is disturbed during the application of the constant current to start depositing metallic copper on the surface of the working electrode to form a copper film layer. In the present embodiment, the current density of the constant current may be preferably 5 to 9 A·dm ^-2 , more preferably 5 to 7.5 A·dm ^-2 , depending on the plating rate required. In addition, the disturbing copper plating solution is mainly for generating a turbulence to allow the composition of the copper plating solution to flow to the working electrode, and the disturbance rate is preferably 150 rpm or less. The direction of the spoiler may not be perpendicular to the surface of the working electrode to form an angle of a predetermined angle, which may be 10 to 80 degrees, for example, 45 degrees.

After completion of S103, a finished product in which a copper film layer is formed on the surface of the working electrode is obtained, and copper plating is completed. Electroplating by the above copper plating solution can shorten the plating time, suppress the occurrence of nodules on the surface of the copper film layer, improve the surface morphology of the copper film layer, and control the copper grain size in the copper film layer.

Further, a method of forming a copper pillar will be described based on FIG.

First, in step S201 of providing a copper plating solution, the composition of the copper plating solution is completely the same as that described in the above step S101.

Next, in step S202, the substrate is provided as a working electrode and a counter electrode is provided, and the working electrode and the counter electrode are immersed in a copper plating solution, wherein a mask having a through hole is formed on the substrate.

The substrate as the working electrode may be a bulk copper as described in step S101.

The manner of forming the mask having the through holes can be unrestricted as needed, for example, a photoresist layer having through holes can be formed by photolithography.

Further, the source of the substrate on which the mask is formed may be a commercially available product, for example, a PCB board having a through hole pattern.

Next, in step S203, a constant current is applied to the working electrode and the counter electrode, and the copper plating solution is disturbed during the application of the constant current to start depositing metallic copper in the through hole.

The current density of the constant current, the rate of disturbing the copper plating solution, and the direction of the disturbance generated by the disturbance are all the same as in step S102.

Next, step S204 is performed, and the mask is removed after the plating is completed.

The manner in which the mask is removed may be unrestricted as needed, for example, the photoresist pattern may be removed by an etching solution that does not etch the metal.

After the completion of step S204, a finished product in which a copper pillar is formed on the surface of the working electrode is obtained, and thus a method of forming a copper pillar is completed. By forming the copper pillar by the above copper plating solution, the plating time can be shortened, the nodules on the top of the copper pillar can be suppressed, the topography of the copper pillar can be improved, and the copper grain size in the copper pillar can be controlled.

Hereinafter, a copper plating solution, a method of plating copper, and a method of forming a copper column of the present invention will be described in detail by way of examples.

[Example 1]

A copper plating solution is supplied with the concentration of FIG. 1 and with reference to Table 1 (finished at the end of the specification), and the prepared copper plating solution is placed in a plating bath of the plating apparatus (step S101). The copper plating bath consists of the following concentrations: 1.2 × 10 ⁵ ppm CuSO ₄ · 5H ₂ O; 1.176 × 10 ⁵ ppm H ₂ SO ₄ ; 60 ppm Cl ^- ; 6 ppm SPS; 240 ppm PEG 20000 And JGB, the concentration ratio of JGB:PEG 20000 is 1:40000.

In order to facilitate the influence of SPS and PEG on the plating potential during the subsequent plating, the role of them in electroplating is understood. Therefore, in the present embodiment, PEG 20000 and SPS are sequentially added when an electric current is applied. In other embodiments, SPS and PEG 20000 have been added to the copper plating bath prior to plating.

Next, the polished and cleaned bulk copper (purity: 99%, 50 mm × 50 mm × 1.5 mm) and the Pt coil were placed in a prepared plating bath and immersed in a copper plating solution. The bulk copper and the Pt coil were respectively used as the working electrode and the counter electrode, and the distance between them was 2.5 cm (step S102).

Next, a constant current density of 5 A·dm ^{-2 was} applied to both electrodes for 5 minutes to start plating. During the electroplating, the copper plating solution was simultaneously disturbed at a rate of 150 rpm, and the generated spoiler direction was at an angle of 45 degrees to the surface of the bulk copper (step S103).

During the electroplating period, the effects of adding SPS and PEG on the plating potential were observed. The relationship between potential and plating time is shown in Figure 3.

Through the above steps, a copper film layer is deposited on the surface of the bulk copper. The surface state of the copper film on the macroscopic view was observed by direct observation, and the copper film layer was observed in the microscopic state by field scanning electron microscopy (FE-SEM; JEOL JSM-6700F, operating voltage 3 kv). Surface morphology and crystal size of copper grains. The observation results are shown in Fig. 4 and Fig. 5, which will be described in further detail later.

[Embodiment 2-16]

Electroplating was carried out in the same manner as in Example 1 except that the added concentrations of SPS and PEG 20000 are shown in Table 1. After the electroplating is completed, the observation results of the surface of the copper film layer are also shown in Figs. 4 and 5.

[Example 17]

Electroplating was carried out in the same manner as in Example 1, except that the concentrations of SPS and PEG 20000, and the current densities are shown in Table 1. After the electroplating is completed, the observation results of the surface of the copper film layer are shown in Figs. 6 and 7.

[Examples 18-19]

Electroplating was carried out in the same manner as in Example 1 except that the concentrations, current densities, and disturbance rates of SPS and PEG 20000 are shown in Table 1. After the electroplating is completed, the SEM image of the surface of the copper film layer is as shown in FIG.

[Example 20]

A method of forming a copper post of the present invention will be described with reference to Fig. 2 through this embodiment.

First, a copper plating solution is prepared according to the SPS and PEG 20000 concentrations shown in Table 2 (finished at the end of the specification), and the prepared copper plating solution is placed in a plating tank of the plating apparatus (step S201), the copper plating solution Contains the following concentration composition: 1.2 × 10 ⁵ ppm CuSO ₄ · 5H ₂ O; 1.176 × 10 ⁵ ppm H ₂ SO ₄ ; 60 ppm Cl ^- ; 9 ppm SPS; 600 ppm PEG 20000; and JGB, The concentration ratio of JGB:PEG 20000 was 1:40000.

Next, a PCB board (having a through-hole pattern mask having a diameter of 120 μm and a depth of 170 μm) and a Pt coil were placed in the prepared plating bath and immersed in the copper plating solution (step S202). The PCB board and the Pt coil are respectively used as the working electrode and the counter electrode, and the distance between them is 2.5 cm.

Next, a constant current density of 7.5 A·dm ^{-2 was} applied to both electrodes for 5 minutes to start plating. During the electroplating, the copper plating solution was simultaneously disturbed at a rate of 60 rpm, and the generated spoiler direction was at an angle of 45 degrees to the surface of the bulk copper (step S203).

After the plating is completed, the mask portion is removed using an etching solution that does not etch copper to obtain a copper pillar formed on the PCB (step S204). The structure of the copper pillar was observed by SEM, and the results were shown in the SEM image of FIG.

[Example 21]

Electroplating was carried out in the same manner as in Example 20, as shown in Table 2, except that the current density was increased to 9 A·dm ^-2 .

[Experimental results]

Figure 3 is a graph of potential versus reaction time during electroplating to illustrate the relationship between potential and reaction time after 240 ppm of PEG 20000 and 6 ppm SPS were sequentially added using the method of electroplating copper of Figure 1.

As shown in FIG. 3, when PEG 20000 was injected into the copper plating solution, the potential was rapidly shifted toward the negative potential and maintained in a stable state. Then, when the SPS is added to the copper plating solution, the potential is shifted toward the positive potential. According to this change in potential, it can be concluded that PEG 20000 has an inhibitory effect and SPS has an acceleration effect. When the potential is in a stable state, it represents a constant current density, so that the electroplating reaction occurs stably on the surface of the bulk copper, thereby forming a flat copper film layer.

Figure 4 shows a photograph of the copper film layer formed on the bulk copper after electroplating of Examples 1-16. As shown in Figure 4, the brightness of the copper layer is dominated by the concentration of SPS: a copper layer that reaches the matte surface at an SPS of 3 ppm, and a bright copper layer when the SPS concentration is increased to a range of 6 to 12 ppm. . Further, as the concentration of PEG increases, the brightness of the copper film layer slightly increases. When the concentration of PEG was increased to 780 ppm, the surface of the bright copper film layer was observed only with SPS of 12 ppm. The surface of the bright copper film layer means that the surface of the copper film layer is more evenly flat.

Figure 5 is an SEM image of each sample taken by FE-SEM. As shown in FIG. 5, it can be seen that as the concentration of SPS and PEG increases, the grain size of copper shrinks. When the concentrations of SPS and PEG were greater than 6 and 420 ppm, respectively, the copper grain size was significantly reduced. However, small pores were observed as the SPS increased to 12 ppm, mainly due to the generation of hydrogen.

When the concentrations of SPS and PEG were 9 ppm and 420 ppm, respectively, in the SEM image of Fig. 5, it was observed that copper crystal grains having a size of about 10 ± 5 nm formed a densely packed surface.

When the copper grain size is smaller, it can be densely packed with each other to form a dense copper film layer, and at the same time, the void defects caused between the copper crystal grains are reduced, thereby improving the structural strength of the copper film layer. Reduce the damage of the copper layer caused by collision or vibration (for example, partial peeling or cracking), thus increasing the yield of the copper layer.

4, 5 and the above description, the quality of the copper film layer can be evaluated by the brightness of the copper film layer and the copper grain size. Among them, PEG 20000 has a concentration of 420 ppm to 600 ppm and a SPS concentration of 6 to 9 ppm has a bright copper film surface and a small size of copper crystal grains.

Further, the current density is a key parameter for controlling the current rate, that is, the high current density can speed up the plating rate, thereby shortening the process time. Therefore, the quality of the copper film layer at a high current density was verified by Example 17.

Fig. 6(a) is a SEM enlarged image of a copper film layer and a nodule formed in Example 17 at a current density of 7.5 A·dm ^-2 . The black spots on the photo are nodules, and it can be observed that only a small number of nodules are produced on the surface of the bulk copper.

Similarly, at a concentration of 420 ppm to 780 ppm and a concentration of SPS of 6 to 12 ppm, a copper layer (not shown) having a small amount of nodulation can be obtained at a current density of 7.5 A·dm ^-2 .

Example 17 demonstrates that a copper film layer with suppressed nodules can be formed at a current density of 7.5 A·dm ^-2 . The size of the copper crystal grains is as shown in Fig. 6(b), which is larger than the size of the copper crystal grains formed at a current density of 5 A·dm ^-2 . Therefore, in the high current density plating process, the size of the copper crystal grains can be further reduced.

With regard to reducing the copper grain size, adjusting the disturbance rate of the disturbed copper plating solution can effectively control the copper grain size, and the results can be confirmed by Examples 17-19. The SEM images of the copper film layers of Examples 17-19 for adjusting the disturbance rate correspond to FIG. 7(a) to FIG. 7(c), respectively, and it can be observed that the copper grain size of FIG. 7(c) is the smallest among the three. Therefore, it was confirmed that as the disturbance rate decreases, the size of the copper crystal grains also shrinks.

To illustrate the effect of the perturbation rate on the size of the copper grains, Figure 8 simulates the growth mechanism of the copper film layer formed on the bulk copper. First, FIG. 8(a) shows a simple plating apparatus 100 in which a working electrode 1 and a counter electrode 2 are respectively provided in a plating tank and filled with a plating solution. Next, as shown in FIG. 8(b), during the electroplating process, Cu ⁺ ion 3 is coordinated to the ether functional group of the PEG molecule 4, and is bonded to the Cl ⁻ ion 5 to form a complex (ie, PEG-Cu ⁺ -Cl). ^- Complex). When the PEG-Cu ⁺ -Cl ^- complex moves toward the working electrode 1 and forms copper crystal 6 when adsorbed on the surface of the electrode, generation of a large copper crystal grain (i.e., nodule 7) can be suppressed. However, the molecular weight of PEG molecule 4 is significantly larger than other additives, and the moving speed is slow. If the plating solution is strongly disturbed during electroplating, the PEG-Cu ⁺ -Cl ^- complex cannot be completely adsorbed on the surface of the working electrode, thus reducing the inhibition. effect. In addition, it is also possible that the long chain of the molecules of the PEG is entangled by the disturbance, and the suppression effect is also lowered.

From this, it can be seen that the inhibitory effect of PEG is easily affected by the flow of the liquid. For PEG 20000, a lower disturbance rate results in a smaller size copper grain.

In addition, the disturbing flow direction generated by the disturbing plating solution is generally perpendicular to the surface of the working electrode to move the PEG molecules 4 straight to the surface of the working electrode. However, in this case, it is easy to increase the chance that a plurality of PEG molecules 4 are entangled with each other. Therefore, when the turbulence direction is at an angle of 10 to 80 degrees with the surface of the working electrode, the moving velocity component of the PEG molecule 4 perpendicular to the working electrode can be reduced. The moving speed component parallel to the working electrode is increased, whereby the entanglement of the PEG molecules 4 with each other can be reduced, thereby improving the effect of suppressing the occurrence of nodules.

Further, a copper plating solution is used to form a copper pillar. The SEM image of the copper pillar is shown in Fig. 9, and Fig. 9(a) is an array of copper pillars having a height of about 60 ± 3 um. In the high-resolution image of Fig. 9(b), it is more observed that the top of the copper pillar has a smooth plane.

During the formation of the copper column, the liquid flow rate at the bottom of the through hole is lower than the external liquid flow rate, and the low liquid flow rate provides that the PEG-Cu ⁺ -Cl ^- composite can be completely adsorbed on the electrode surface at the bottom of the through hole. surroundings. Thus, during electroplating, a flat top copper pillar with a tightly packed surface can be grown in the via.

Therefore, by the method of forming a copper pillar according to the present invention, electroplating can be performed at a high current density of 7.5 A·dm ^-2 , which shortens the process time. Since the formed copper pillar has a flat top, it is possible to planarize the top of the copper pillar without introducing a CMP process, thereby saving production costs.

Further, in Embodiment 22, when the current density is increased to 9 A·dm ^-2 , a bump (not shown) starts to appear at the top of the copper pillar, but a copper pillar having a high copper grain filling density can still be obtained. The plating time is also greatly shortened.

According to the verification of the above embodiment, a copper plating solution, a method of electroplating copper, and a method of forming a copper pillar of the present invention. Compared with the conventional copper plating solution using PEG 4000-8000, the present invention selects PEG 20000 with higher molecular weight, performs electroplating at an increased current density, shortens the plating time, and inhibits the formation of nodules on the surface.

In addition, by adjusting the concentration of PEG and SPS, thereby controlling the copper grain size in the copper film layer to improve the filling density of the copper film layer, the quality of the copper film layer can be further improved, and the yield of the copper film layer can be further improved. .

Furthermore, by using the copper plating solution of the present invention to form a copper pillar, the quality and topography of the copper pillar can be improved. Among them, under the condition that the copper pillar having a flat top is directly formed, the CMP process for flattening the top of the copper pillar can be omitted, which saves the production cost.

The illustrations and descriptions of the present invention are merely preferred embodiments of the present invention, and are not intended to limit the implementation of the present invention, and those who are familiar with the art are subject to the changes in the spirit of the present invention. Or the modifications should be covered by the following patent application in this case.

Table 1  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> Substance (ppm) </td><td> Current Density ( A·dm^-2) </td><td> Disturbance Rate (rpm) </td></tr><tr><td> PEG 20000 </td><td> SPS < /td></tr><tr><td> Example 1 </td><td> 240 </td><td> 6 </td><td> 5 </td><td> 150 </ Td></tr><tr><td> Example 2 </td><td> 240 </td><td> 3 </td></tr><tr><td> Example 3 </ Td><td> 240 </td><td> 9 </td></tr><tr><td> Example 4 </td><td> 240 </td><td> 12 </td ></tr><tr><td> Example 5 </td><td> 420 </td><td> 3 </td></tr><tr><td> Example 6 </td ><td> 420 </td><td> 6 </td></tr><tr><td> Example 7 </td><td> 420 </td><td> 9 </td> </tr><tr><td> Example 8 </td><td> 420 </td><td> 12 </td></tr><tr><td> Example 9 </td> <td> 600 </td><td> 3 </td></tr><tr><td> Example 10 </td><td> 600 </td><td> 6 </td>< /tr><tr><td> Example 11 </td><td> 600 </td><td> 9 </td></tr><tr><td> Example 12 </td>< Td> 600 </td><td> 12 </td></tr><tr><td> Example 13 </td><td> 780 </td><td> 3 </td></ Tr><tr><td> Example 14 </td><td> 780 </td><td> 6 </td></tr><tr><td> Example 15 </td><td> 780 </td><td> 9 < /td></tr><tr><td> Example 16 </td><td> 780 </td><td> 12 </td></tr><tr><td> Example 17 < /td><td> 600 </td><td> 9 </td><td> 7.5 </td><td> 150 </td></tr><tr><td> Example 18 </ Td><td> 600 </td><td> 9 </td><td> 7.5 </td><td> 100 </td></tr><tr><td> Example 19 </td ><td> 600 </td><td> 9 </td><td> 7.5 </td><td> 60 </td></tr></TBODY></TABLE>

Table 2  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> Substance (ppm) </td><td> Current Density ( A·dm^-2) </td><td> Disturbance Rate (rpm) </td></tr><tr><td> PEG 20000 </td><td> SPS < /td></tr><tr><td> Example 20 </td><td> 600 </td><td> 9 </td><td> 7.5 </td><td> 60 </ Td></tr><tr><td> Example 21 </td><td> 600 </td><td> 9 </td><td> 9 </td><td> 60 </td ></tr></TBODY></TABLE>

S101～S103‧‧‧Steps

S201～S204‧‧‧Steps

100‧‧‧ plating equipment

1‧‧‧Working electrode

2‧‧‧ opposite electrode

3‧‧‧Cu ⁺ ions

4‧‧‧PEG

5‧‧‧Cl ^- ion

6‧‧‧ copper grain

7 ‧ ‧ section

1 is a flow chart of a step of electroplating copper; FIG. 2 is a flow chart of a step of forming a copper post; FIG. 3 is a graph of potential and reaction time during electroplating; and FIG. 4 is a copper film formed on a bulk copper after electroplating. Figure 5 is an SEM image of a copper film formed on a bulk copper after electroplating; Figure 6 is a photo and SEM image of a copper film formed on a bulk copper at a current density of 7.5 A·dm ^-2 ; Photographs and SEM images of the copper film formed on the bulk copper at different perturbation rates; Figure 8 is a simulation of the growth mechanism of the copper film formed on the bulk copper; Figure 9 is a SEM of the copper column with a flat top image.

Claims (9)

A copper electroplating solution comprising the following composition: 1.2×10 ⁵ to 1.8×10 ⁵ ppm of copper sulfate pentahydrate; 9.8×10 ⁴ to 1.372×10 ⁵ ppm sulfuric acid; 50 to 70 ppm of chloride ion; 3 to 12 ppm Dithiodipropane sulfonate; 420-600 ppm polyethylene glycol; and Jianna Green B, wherein the polyethylene glycol has a molecular weight of 20,000, and the Jianna Green B: the concentration of the polyethylene glycol The ratio is 1:40000. The copper plating solution according to claim 1, wherein the concentration of the dithiodipropane sulfonate is further 6 to 12 ppm. A method of electroplating copper, the method comprising: providing a substrate as a working electrode and providing a pair of electrodes, the working electrode and the pair of electrodes being immersed in a copper plating solution; applying a constant to the working electrode and the pair of electrodes The current is disturbed during the application of the constant current, wherein the copper plating solution is the copper plating solution described in claim 1 or 2. The method of electroplating copper according to claim 3, wherein the material of the substrate comprises copper. The method of electroplating copper according to claim 3, wherein the constant current has a current density of 5 A. Dm ^-2 ~9A. Dm ^-2 . The method of electroplating copper according to claim 5, wherein the constant current has a current density of 7.5 A. Dm ^-2 or less. The method of electroplating copper according to claim 3, wherein the disturbance rate of disturbing the copper plating solution is 150 rpm or less. The method of electroplating copper according to claim 3, wherein the disturbing flow direction generated by the copper plating solution is at an angle of 10 to 80 degrees with the surface of the working electrode. A method of forming a copper pillar, the method comprising: providing a substrate as a working electrode and providing a pair of electrodes, the working electrode and the pair of electrodes being immersed in a copper plating solution, wherein the substrate is formed with a through hole a mask; applying a constant current to the working electrode and the pair of electrodes to deposit copper in the via hole, disturbing the copper plating solution during application of the constant current; and removing the mask, thereby A copper pillar is formed on the substrate, wherein the copper plating solution is the copper plating solution described in claim 1 or 2.