Insoluble anode plating equipment

Abstract

To provide a plating apparatus for an insoluble anode capable of continuously performing a good and uniform copper plating treatment by suppressing fluctuation of the copper concentration of a plating solution for a cathode as much as possible and suppressing consumption of an additive included in the plating solution for a cathode.SOLUTION: A plating apparatus for an insoluble anode including a diaphragm 11 includes copper oxide powder supply means for supplying copper oxide powder together with a carrier gas to a management tank 2 through a supply tube 42 having static electricity removal performance. An upper lid 21 of the management tank includes a powder supply cylinder 43 having a tip disposed near the liquid level of the cathode plating solution stored in the management tank and having a static electricity removal performance. A feeding tube is connected to the powder supply cylinder.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plating apparatus for insoluble anodes. [Background technology]

[0002] Conventionally, various plating processes have been performed on objects to be plated, such as semiconductor wafers, printed wiring boards, etc. When performing plating processes on such objects to be plated, a so-called jet-type plating apparatus is known.

[0003] This jet-type plating apparatus generally comprises an opening on which the object to be plated can be placed, a liquid supply pipe for supplying plating solution to the object to be plated, and an anode arranged to face the object to be plated, and performs plating while supplying plating solution from the liquid supply pipe to the object to be plated. Jet-type plating apparatuses can perform uniform plating on the surface of the object to be plated, and can sequentially replace the object to be plated placed in the opening for plating, so they are widely used as suitable for small-lot production and automation of plating.

[0004] Although this type of jet-type plating apparatus has the advantages described above, when a soluble anode is used, a film formed on the anode surface, such as a black film, may peel off and become an impurity in the plating solution. This may then flow together with the plating solution supplied toward the object to be plated, adversely affecting the plating process.

[0005] In addition, air mixed in the liquid or bubbles generated from the anode may reach the surface to be plated and impede good plating. For this reason, a method is known for this jet-type plating device in which a diaphragm is placed in the plating tank to separate the object to be plated from the anode (see Patent Documents 1 and 2).

[0006] The use of insoluble anodes in jet-type plating equipment equipped with a diaphragm offers various advantages over the use of soluble anodes, such as reducing the consumption of additives in the plating solution and improving productivity by eliminating the need for maintenance such as anode replacement as in the case of soluble anodes.

[0007] However, although jet-type plating equipment using insoluble anodes has many advantages over soluble anodes, its use within the plating industry has not progressed much except for precious metal plating and copper plating.

[0008] When the diaphragm is placed in the plating tank of the jet-type plating apparatus, an upper isolation chamber is formed above the diaphragm by the diaphragm and the object to be plated placed on the opening, and a lower isolation chamber is formed below the diaphragm by the plating tank and the diaphragm. Since the insoluble anode is placed on the lower isolation chamber side, a large amount of bubbles appear below the diaphragm during plating due to gas generation caused by electrolysis of water. Therefore, it is necessary to efficiently discharge the bubbles that appear below the diaphragm. In addition, in order to obtain the advantages of using the insoluble anode, different types of solutions may be supplied separately to the upper isolation chamber and the lower isolation chamber, but it is necessary to prevent the different types of solutions supplied to the upper isolation chamber and the lower isolation chamber from mixing with each other by the diaphragm placed in the plating tank.

[0009] In the prior art of Patent Document 1, when supplying a solution to the upper isolation chamber, the pressure loss during supply is large, so the supply flow rate to the lower isolation chamber cannot be increased very much, and the large amount of bubbles generated from the insoluble anode tends to be unable to be sufficiently discharged. In addition, in Patent Document 2, although the bubbles can be efficiently discharged in the lower isolation chamber, the solutions supplied to the upper isolation chamber and the lower isolation chamber cannot be separated, so the benefits of the insoluble anode cannot be fully realized.

[0010] In order to solve the problems of such a jet-type insoluble anode plating apparatus in which a diaphragm is arranged in a plating tank, the prior art described in Patent Document 3 (WO2022 / 107551) has been proposed. In Patent Document 3, the solutions supplied to the upper and lower isolation chambers do not mix with each other, and bubbles generated from the insoluble anode in the lower isolation chamber can be efficiently discharged, so that the advantages of the insoluble anode can be fully realized.

[0011] In a plating apparatus using an insoluble anode, for example, when performing copper plating, it is necessary to adjust the concentration of copper in the plating solution consumed in the plating process. As one method for adjusting the copper concentration, a method using copper oxide powder has been proposed (Patent Document 4). The prior art of Patent Document 4 proposes that by using copper oxide powder with a specified content of impurities such as sodium and periodically adding the copper oxide powder to the plating solution, the copper concentration in the plating solution can be controlled within a predetermined range, and good copper plating can be performed on semiconductor substrates such as wafers. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2000-273693 A [Patent Document 2] JP 2007-169773 A [Patent Document 3] International Publication No. WO2022 / 107551 [Patent Document 4] JP 2018-62453 A Summary of the Invention [Problem to be solved by the invention]

[0013] As described above, plating apparatus using insoluble anodes have various advantages over plating apparatus using soluble anodes, and various plating processing techniques that can fully utilize these advantages have been proposed. However, further technological development is required for plating apparatus using insoluble anodes.

[0014] Copper plating is performed to fill minute vias in semiconductor wafers and other plated objects. Recently, electronic substrates and other devices have become lighter, thinner, shorter, and smaller. For example, vias have become significantly smaller. For example, plating equipment that can perform good copper plating uniformly on minute vias with high aspect ratios, such as via diameters of 5 μm and via depths of 100 μm, is required. When performing such fine copper plating with an insoluble anode plating equipment, it is extremely important to manage the concentration of copper and additives in the plating solution. Specifically, when copper sulfate solution is used as the plating solution for copper plating of semiconductor wafers, additives (commercially available products) called accelerators, suppressors, and levelers are added to the plating solution. These additives tend to be consumed by continuing the plating process, and consumption also occurs in insoluble anode plating equipment equipped with a diaphragm. In an insoluble anode plating apparatus equipped with a diaphragm, a copper sulfate solution is supplied as a cathode plating solution to the upper isolated chamber formed by the diaphragm. As the copper plating process continues, the copper concentration of the cathode plating solution decreases. In a copper sulfate solution with a decreased copper concentration, the sulfate ion (SO4 2-) will increase. In a copper sulfate solution with a relatively increased sulfate ion concentration, additives in the solution tend to be consumed more, making it difficult to perform uniform and good copper plating. In particular, when copper plating is performed on fine vias or fine trenches with a high aspect ratio, the copper plating thickness is extremely thin, so in order to perform uniform and continuous copper plating of a thin thickness, it is necessary to suppress fluctuations in the copper concentration in the plating solution and consumption of additives as much as possible. In other words, there is a demand for a plating device for an insoluble anode that enables continuous copper plating while suppressing fluctuations in the copper concentration of the copper sulfate solution as the plating solution as much as possible.

[0015] The present invention has been made under the above circumstances, and has an object to provide an insoluble anode plating apparatus equipped with a diaphragm, which, when copper plating is performed on a plated object such as a semiconductor wafer, minimizes fluctuations in the copper concentration in the cathode plating solution, suppresses consumption of additives contained in the cathode plating solution, and makes it possible to continuously perform good and uniform copper plating on fine vias and fine trenches with high aspect ratios. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention provides a plating tank having an opening for placing an object to be plated, a liquid supply pipe for supplying a plating solution toward the object to be plated, an insoluble anode arranged to face the object to be plated, and a diaphragm for isolating the object to be plated and the insoluble anode, the diaphragm is arranged so that an outer peripheral end of the diaphragm is fixed to the inner wall of the plating tank, and a peripheral end of a through hole provided in the center of the diaphragm is fixed to the liquid supply pipe, so that an upward inclination is given from the liquid supply pipe toward the outer periphery, and the liquid supply pipe is arranged so that an upper isolation chamber in the plating tank formed by the diaphragm and the placed object to be plated is provided with a cathode plating solution. The insoluble anode plating apparatus is configured to supply a cathode plating solution to a lower isolated chamber in a plating tank formed below a diaphragm from an anode solution tank in which the anode solution is stored, the insoluble anode plating apparatus comprising: a copper oxide powder supply means for supplying copper oxide powder together with a carrier gas to a management tank via a supply tube having static electricity removal capability; a powder supply cylinder having static electricity removal capability and whose tip is located near the liquid level of the cathode plating solution stored in the management tank is provided on an upper lid of the management tank; and the supply tube is connected to the powder supply cylinder.

[0017] According to the present invention, by supplying copper oxide powder equivalent to the amount of copper used in the plating process to the cathode plating solution, it is possible to continuously maintain the copper concentration within the set range, and therefore it is possible to reliably suppress the consumption of additives due to fluctuations in copper concentration caused by the plating process. As a result, it is possible to continuously perform good and uniform copper plating even on fine vias and fine trenches with high aspect ratios. In the present invention, the reason why the copper oxide powder is supplied to the cathode plating solution from a powder supply cylinder having a static electricity removing function and a tip located near the liquid surface of the cathode plating solution stored in the management tank is to ensure that powdered copper oxide is introduced into the cathode plating solution. If the tip of the powder supply cylinder is separated from the liquid surface of the cathode plating solution stored in the management tank, the amount of copper oxide powder supplied from the powder supply cylinder that scatters into the space above the liquid surface of the cathode plating solution increases, making it difficult to adjust the copper concentration. Furthermore, if the tip of the powder supply cylinder comes into contact with the liquid surface, the copper oxide powder will aggregate and adhere to the tip, making it difficult to supply the copper oxide powder. Therefore, in the present invention, the tip of the powder supply cylinder is positioned near the liquid surface of the cathode plating solution stored in the management tank. Near means a distance where the tip does not come into contact with the liquid surface, and a distance where the copper oxide powder supplied from the tip does not scatter into the space above the liquid surface of the cathode plating solution. The distance between the tip of this powder supply cylinder and the liquid surface of the cathode plating solution is set to be equal to the average particle size The distance can be appropriately adjusted according to the physical properties such as those mentioned above, but is preferably 50 to 100 mm.

[0018] The present invention also provides a plating tank having an opening for placing an object to be plated, a liquid supply pipe for supplying a plating solution toward the object to be plated, an insoluble anode arranged to face the object to be plated, and a diaphragm for isolating the object to be plated and the insoluble anode, the diaphragm is arranged so that an outer peripheral end thereof is fixed to an inner wall of the plating tank, and a peripheral end of a through hole provided in the center of the diaphragm is fixed to the liquid supply pipe, thereby providing an upward inclination from the liquid supply pipe toward the outer periphery, and a cathode plating solution is supplied from a control tank storing a cathode plating solution through the liquid supply pipe to an upper isolated chamber in the plating tank formed by the diaphragm and the placed object to be plated, The present invention relates to an insoluble anode plating apparatus in which an anode solution is supplied from an anode solution tank storing the anode solution to a lower isolated chamber in a plating tank formed below a diaphragm, the insoluble anode plating apparatus being provided with a copper concentration adjustment tank for adjusting the copper concentration of a cathode plating solution, the copper concentration adjustment tank having a copper oxide powder supply device that transports copper oxide powder together with a carrier gas through a supply tube having static electricity removal capability, the upper cover of the copper concentration adjustment tank is provided with a powder supply cylinder having static electricity removal capability and whose tip is located near the liquid surface of the cathode plating solution stored in the copper concentration adjustment tank, the copper concentration adjustment tank is provided with stirring means for stirring the cathode plating solution, the supply tube is connected to the powder supply cylinder, the copper oxide powder is supplied to the copper concentration adjustment tank to adjust the copper concentration of the cathode plating solution in the copper concentration adjustment tank, and the cathode plating solution with the adjusted copper concentration is supplied from the copper concentration adjustment tank to a control tank.

[0019] The insoluble anode plating apparatus of the present invention is suitable for copper plating of semiconductor wafers and other objects to be plated, but since the manufacture of semiconductor wafers and other objects to be plated is carried out in a so-called clean room, it is considered that copper oxide powder, which is easily scattered, may contaminate the inside of the clean room. Therefore, by arranging a copper concentration adjustment tank outside the clean room, adjusting the copper concentration using copper oxide powder in the copper concentration adjustment tank, and supplying the adjusted cathode plating solution to the control tank, contamination inside the clean room can be reliably prevented.

[0020] In the present invention, the copper oxide powder has an average particle size of 25 to 40 μm and a bulk density of 1.7 g / cm 3 It is preferable that the compacted bulk density is less than 1.7 g / cm 3 If the concentration is more than this, the dissolution of the copper oxide powder in the cathode plating solution tends to be slow. More preferably, it is 1.5 g / cm. 3 or more and less than 1.7 g / cm3. The term "packed bulk density" refers to the bulk density measured after filling a specified container with copper oxide powder gently, applying a certain amount of vibration to the container to fill the gaps between the powder particles, and refilling the container. The packed bulk density in the present invention is a value measured using a graduated cylinder. Furthermore, the copper oxide powder in the present invention preferably has a relatively small angle of repose (10° to 12.5°). This angle of repose is obtained by dropping 100 mL of the copper oxide powder, the packed bulk density of which has been measured using a graduated cylinder, from a position 15 cm high to create a mountain-shaped mass of copper oxide powder, and measuring the angle of the base of the mountain-shaped mass. If the copper oxide powder has a large angle of repose, the dissolution rate tends to be slow. This angle of repose is an index of the fluidity of the copper oxide powder, and if the copper oxide powder has an angle of repose of 10° to 12.5°, the solubility of the copper oxide powder is high. The gaps between powder particles are generated due to geometric factors of the particle shape and surface characteristics such as adhesion. According to the inventor's findings, the bulk density of copper oxide powder is 1.6 g / cm 3 It was found that when the copper oxide powder has a particle shape of about 10°, the dissolution of the copper oxide powder in the cathode plating solution proceeds quickly. Furthermore, it was also found that when the copper oxide powder has a particle shape of granules, the dissolution of the copper oxide powder proceeds quickly. This is thought to be related to the fact that the angle of repose of the copper oxide powder is relatively small (10° to 12.5°).

[0021] The powder supply cylinder in the present invention has a static electricity removing function, and is preferably made of a grounded titanium material or a powder supply cylinder connected to a static eliminator (ionizer). If static electricity occurs in the powder supply cylinder, the copper oxide powder is likely to aggregate, making it difficult to stably supply the copper oxide powder.

[0022] In the present invention, the carrier gas suitable for supplying the copper oxide powder from the copper oxide powder supplying device through a supply tube having static electricity removing properties is preferably nitrogen gas or argon gas. The use of nitrogen gas or argon gas suppresses the aggregation of the copper oxide powder, and can reliably reduce adhesion of the copper oxide powder to the supply tube and prevent clogging.

[0023] In the insoluble anode plating apparatus according to the present invention, it is preferable to provide a switching means in the supply tube that can switch between supplying a carrier gas and copper oxide powder and supplying only the carrier gas. When the supply of copper oxide powder is stopped, by supplying only the carrier gas to the supply tube, it is possible to prevent the copper oxide powder from agglomerating in the supply tube and reliably prevent adhesion or clogging of the copper oxide powder.

[0024] In the plating apparatus for insoluble anodes according to the present invention, it is preferable to dispose a powder flow meter in the supply tube for monitoring the supply state of the copper oxide powder, and to provide a powder supply control means for controlling the adjustment of the supply amount of the copper oxide powder and the stop of the supply. By monitoring the supply state with the powder flow meter, it is possible to appropriately fine-tune the supply amount of the copper oxide powder and stop the supply of the copper oxide powder in the event of an abnormality. In addition, as a means for confirming that the copper concentration in the copper plating solution has been reliably adjusted, it is preferable to install copper concentration meters in the piping before and after the copper concentration adjustment tank, and to monitor whether the copper used in the plating process has been accurately replenished.

[0025] In the insoluble anode plating apparatus according to the present invention, in order to prevent the separate solutions supplied to the lower isolation chamber and the upper isolation chamber from directly mixing with each other, it is preferable to fix a silicon ring to the outer circumferential edge of the diaphragm and the edge of the through-hole of the diaphragm. When fixing the silicon ring to the diaphragm, it is preferable to use a manufacturing method called simultaneous casting of the silicon ring. In the simultaneous casting of the silicon ring, the diaphragm is fixed to a mold that can press the outer circumferential edge of the diaphragm and the edge of the through-hole from above and below, and an adhesive (primer) is applied to the outer circumferential edge portion and the edge of the hole to which the silicon ring is fixed, and silicon is injected into the portion to which the adhesive is applied, and the mold is then pressed. After the silicon hardens, the mold is removed, leaving the silicon ring fixed to the outer circumferential edge of the diaphragm and the edge of the through-hole of the diaphragm. A diaphragm having such a silicon ring fixed thereto can reliably prevent leakage of solution from the outer peripheral edge of the diaphragm which is fixed to the inner wall of the plating tank and from the peripheral edge of the through hole in the center of the diaphragm which is fixed to the solution supply pipe. There are no particular restrictions on the material of the diaphragm to be used, and it may be selected in consideration of the liquid permeability and plating solution resistance, but it is preferable to use a diaphragm whose diaphragm base material is polyethylene terephthalate resin and whose diaphragm material is a polyvinylidene fluoride resin-based material. In addition, the water permeability should be 0.1 mL / min / cm. 2 It is preferable that:

[0026] Although the insoluble anode plating apparatus according to the present invention is intended for copper plating, it can be used for any plating process in which the plating metal or plating solution components can be supplied as powder. For example, when performing non-cyanide gold plating containing gold sulfite, the insoluble anode plating apparatus according to the present invention can be used to supply sulfite powder to replenish the sulfite consumed by the plating process. The insoluble anode plating apparatus according to the present invention can also be used in electrolytic nickel plating using an insoluble anode. Effect of the Invention

[0027] According to the present invention, in an insoluble anode plating apparatus equipped with a diaphragm, the copper concentration of the cathode plating solution can be continuously maintained within a predetermined range, thereby suppressing consumption of additives contained in the cathode plating solution and enabling continuous, satisfactory and uniform copper plating treatment to be performed on fine vias and fine trenches with high aspect ratios. [Brief description of the drawings]

[0028] [Figure 1] 1 is a schematic cross-sectional view of an insoluble anode plating apparatus according to an embodiment of the present invention. [Diagram 2] 2 is a schematic cross-sectional view of a plating tank of the insoluble anode plating apparatus according to the embodiment of the present invention. FIG. [Diagram 3] 1 is a schematic cross-sectional view of an insoluble anode plating apparatus equipped with a copper concentration adjustment tank according to the present embodiment. [Figure 4] SEM photograph of copper oxide powder A. [Diagram 5] SEM photograph of copper oxide powder B. [Figure 6] Cross-sectional photograph of a copper-plated via. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view of an insoluble anode plating apparatus according to this embodiment, and Fig. 2 is a schematic cross-sectional view of a plating tank.

[0030] The plating apparatus for an insoluble anode in Fig. 1 is composed of a plating tank 1, a control tank 2, and an anode solution tank 3. A copper oxide powder feeder 4 is disposed near the control tank 3.

[0031] First, the plating tank 1 shown in Fig. 1 will be described with reference to Fig. 2. A doughnut-shaped diaphragm 11 having a through hole in the center is installed in the plating tank 1. The outer peripheral end of the diaphragm 11 is fixed to an inner wall 12 of the plating tank, and the peripheral end of the through hole is fixed to the tip side of a liquid supply pipe 13, so that the diaphragm 11 is inclined upward from the liquid supply pipe 13 toward the outer periphery. An annular flow path 14 is provided on the outer periphery of the liquid supply pipe 13. A mesh-like insoluble anode 15 is disposed at the bottom of the plating tank 1.

[0032] When a wafer W to be plated is placed in the opening of plating tank 1, an upper isolated chamber U and a lower isolated chamber D are formed in plating tank 1. A cathode plating solution is supplied to the upper isolated chamber U through a solution supply pipe 13. An anode solution from an anode solution tank 3 is supplied to the lower isolated chamber D through an annular flow path 14.

[0033] The cathode plating solution stored in the management tank 2 is supplied from a liquid supply pipe 13 to an upper isolated chamber U in the plating tank 1, and is discharged from the outer circumferential end side of the diaphragm 11 to return to the management tank 2. A copper oxide powder supplyer 4 disposed near the management tank 1 supplies copper oxide powder from a powder storage chamber 41 together with a carrier gas G through a supply tube 42 into the management tank 1 from a powder supply cylinder 43 attached to the upper lid 21 of the management tank 1. The tip of the powder supply cylinder 43 is disposed near the liquid surface of the cathode plating solution.

[0034] The supply tube 42 of the copper oxide powder supply device 4 is equipped with a switching device 44 that can switch between supplying carrier gas and copper oxide powder and supplying carrier gas only, and a powder supply control device 45 that has a powder flow meter that monitors the supply state of the copper oxide powder and is used to adjust the amount of copper oxide powder supplied and to control the stopping of supply.

[0035] Although not shown in the figure, the management tank 2 is equipped with a magnetic stirrer function as a liquid stirring means, and when copper oxide powder is supplied to the management tank 2, the liquid is stirred so that the copper oxide powder can be dissolved quickly. Also, although not shown in the figure, a copper concentration meter is attached to the management tank 2 so that the copper concentration of the cathode plating solution can be measured at all times. If the copper concentration of the cathode plating solution falls outside the set range due to plating processing, the copper concentration is controlled so that the copper oxide powder supplier 4 is operated by a signal from the copper concentration meter and the required amount of copper oxide powder is supplied to the management tank 2.

[0036] Fig. 3 shows an insoluble anode plating apparatus equipped with a copper concentration adjustment tank. The copper concentration adjustment tank 5 is configured to send the cathode plating solution, in which the copper concentration has been adjusted, to the management tank 2, and to recover the cathode plating solution from the management tank 2. A copper oxide powder supplier 4 is disposed near the copper concentration adjustment tank 5. The right side of the thick dashed line in Fig. 3 is inside the clean room, and the left side of the thick dashed line is outside the clean room. Since the copper concentration adjustment tank 5 and the copper oxide powder supplier 4 are disposed outside the clean room, it is possible to reliably prevent contamination of the inside of the clean room with copper oxide powder.

[0037] The copper concentration adjustment tank 5 in FIG. 3 is provided with a magnetic stirrer function as a liquid stirring means, which is omitted from the drawing, so that when copper oxide powder is supplied to the copper concentration adjustment tank 5, the liquid is stirred to quickly dissolve the copper oxide powder. In addition, although not shown, a copper concentration meter is attached to the copper concentration adjustment tank 5, so that the copper concentration of the cathode plating solution can be measured at all times. When the copper concentration of the cathode plating solution stored in the control tank 2 falls outside the set range and the copper concentration drops, the copper oxide powder supplying device 4 is operated by a signal from the copper concentration meter attached to the control tank 2, and is controlled to supply the required amount of copper oxide powder to the copper concentration adjustment tank 5. The plating tank 1, the anode solution tank 2, and the copper oxide powder supplying device 4 in FIG. 3 are the same as those described in FIG. 1.

[0038] <Solubility of copper oxide powder> Next, the results of examining the solubility of the copper oxide powder in the present invention will be described. The following three types of copper oxide powder were used for the evaluation. Copper oxide powder A: Average particle size 30μm (FCO-M6 manufactured by Furukawa Chemicals Co., Ltd.) Copper oxide powder B: Average particle size 3.7μm (FCO-500 manufactured by Furukawa Chemicals Co., Ltd.) Copper oxide powder C: average particle size μm (YS-808 Kunshan Deku▲Ken▼Manufactured by New Materials Technology Co., Ltd.)

[0039] The dissolution rate, bulk density, and angle of repose of each copper oxide powder were measured under the following test conditions: Dissolution rate: A copper sulfate solution (MF-Cu525, manufactured by EEJA Co., Ltd.) was used as the plating solution, and a specified amount of copper oxide powder was added to a beaker containing 1 L of plating solution (liquid temperature 22°C). The time until the blackened copper sulfate solution returned to its original color due to complete dissolution of the copper oxide powder, and the copper concentration of the plating solution after a specified time had passed were measured. The amount of dissolution was measured from the copper concentration before and after the addition of the copper oxide powder, and the dissolution rate of the copper oxide powder was measured from the time until complete dissolution. Compacted bulk density: A small amount of copper oxide powder was added to a 200 mL measuring cylinder, and the powder was compacted by hitting the bottom of the measuring cylinder on a table three times. This compacting process was repeated to add copper oxide powder until the total volume reached 100 mL. The weight of the added copper oxide powder was measured to measure the compacted bulk density. Angle of repose: The copper oxide powder (100 mL) filled into the 200 mL measuring cylinder in which the packed bulk density was measured above was dropped onto a desk from a height of 15 cm to create a mountain-shaped lump of copper oxide powder, and the angle of the base of the mountain-shaped lump was measured.

[0040] The measurement results of the dissolution rate, bulk density, and angle of repose for each copper oxide powder are shown in Table 1.

[0041] [Table 1]

[0042] As shown in Table 1, copper oxide powder A had the highest dissolution rate and a bulk density of 1.6. On the other hand, copper oxide powder B had the slowest dissolution rate, a bulk density of 2.23, and a large angle of repose of 22.5. Copper oxide powder C had a slower dissolution rate than A, but a bulk density of 1.22 and an angle of repose of 15. From this, it was determined that the bulk density was 1.6 g / cm. 3 It was found that copper oxide powder with an angle of repose of about 12.5° had a fast dissolution rate.

[0043] The particle morphology observation by SEM and the specific surface area measurement results for copper oxide powders A and B are described below. Figure 4 shows SEM observation photographs of copper oxide powder A, and Figure 5 shows SEM observation photographs of copper oxide powder B. In Figures 4 and 5, the upper row is an observation photograph at a magnification of 1000 times, and the lower row is an observation photograph at a magnification of 50,000 times. As shown in Figure 4, at a magnification of 1000 times, many particles with a diameter of 20 μm or more were confirmed in copper oxide powder A. Furthermore, when observed at a magnification of 50,000 times, fine particles with a diameter of sub-μm or less were confirmed over the entire field of view in copper oxide powder A. And, as shown in Figure 5, many particles with a diameter of 2 to 3 μm were confirmed in copper oxide powder B at both magnifications of 1000 times and 50,000 times. The specific surface area of ​​copper oxide powder A is 23 m 2 / g, and the specific surface area of ​​copper oxide powder A is 0.8 m 2 / g. Considering the results of the SEM observation and the specific surface area measurement, it is clear that although the average particle size of copper oxide powder A is large at 30 μm, particles of this average particle size are formed by the aggregation of fine particles. Since copper oxide powder A is a granular powder made up of fine particles, it is believed that the powder has good fluidity and a relatively small angle of repose.

[0044] <Copper plating test> Next, the results of a copper plating test in which a copper plating process was performed using a copper sulfate plating solution by the plating apparatus of this embodiment will be described. This copper plating test was performed using the insoluble anode plating apparatus described in Figure 1. A commercially available device (MX-750: manufactured by Kinseisha Co., Ltd.) was used as the copper oxide powder feeder.

[0045] In this test, copper sulfate plating solution containing three types of additives (commercially available products) called accelerator, suppressor, and leveler was supplied to the upper isolated chamber on the cathode side, and copper sulfate plating solution without additives was supplied to the lower isolated chamber on the anode side. The solution composition is shown below.

[0046] *Upper isolation room supply fluid: Copper sulfate plating solution (commercially available Microfab Cu525 / manufactured by EEJA Co., Ltd.) Copper concentration...60g / L Sulfuric acid concentration...30g / L Accelerator 5W (accelerator) 3mL / L Suppressor: 10mL / L Leveler (smoothing agent) 10mL / L Liquid temperature: 22~23℃ Liquid volume: 40L ·Supply flow rate 25L / min *Lower isolation room supply fluid: Copper sulfate plating solution (commercially available Microfab Cu525 / EEJA Co., Ltd., same solution as in the upper isolation chamber) Liquid temperature: 22~25℃ Liquid volume: 20L ·Supply flow rate 5L / min

[0047] The plating equipment used a mesh-shaped insoluble anode made of Pt-Ti, and the diaphragm was a commercially available product (membrane material: fluororesin, thickness: 0.12 mm, water permeability: 0.08 mL / min / cm 225℃) was used. An 8-inch PCB wafer was used as the object to be plated. This PCB wafer was made by attaching copper foil to a glass epoxy base material and processing it into a circular wafer shape.

[0048] In this copper plating test, a running test was carried out in which copper plating was performed and copper oxide powder was supplied, and the change in concentration of the additive contained in the upper isolation chamber supply solution was examined. The copper oxide powder used was the above-mentioned copper oxide powder A, and the carrier gas was nitrogen gas. The supply tube was made of PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer) with an inner diameter of 1 mm and an outer diameter of 2 mm, and the powder supply cylinder was made of PFA with an inner diameter of The tip of this powder supply cylinder (the side from which the copper oxide powder was blown out) was positioned approximately 80 mm above the plating solution surface in the control tank.

[0049] The copper plating conditions were as follows: plating current was supplied at an average current density of 0.91 A / dm2 (plating time 44 min) so that the amount of Cu deposited per wafer was 0.45 g. In addition, when copper plating was performed on one wafer, 0.5625 g of copper oxide powder A was supplied to the plating solution in the control tank. The nitrogen gas flow rate was 0.06 L / min (equivalent to a supply of copper oxide powder A of 0.3 g / min). In the control tank where copper oxide powder A was supplied, the liquid was stirred using a magnetic stirrer function.

[0050] Copper plating was performed on four wafers in sequence, and the plating solution in the upper isolation chamber was sampled after each plating process to analyze the additive concentration. The copper concentration after each plating process was also analyzed. As a result, it was confirmed that the concentrations of the three additives in the copper sulfate plating solution supplied to the upper isolation chamber hardly changed. The copper concentration of the copper sulfate plating solution supplied to the upper isolation chamber was also kept almost constant. When the copper sulfate plating solution in the lower isolation chamber was analyzed after each plating process, the components of the three additives were not analyzed. This confirmed that the additives in the copper sulfate plating solution in the upper isolation chamber had not moved to the lower isolation chamber.

[0051] Next, the results of the copper embedding plating test of vias will be explained. In this test, a silicon wafer was used in which a via with a diameter of 30 μm and a depth of 70 μm was formed. Copper was embedded in this via, and a pad with a thickness of 12 μm and a diameter of 80 μm was continuously formed on the top of the via by copper plating. The copper sulfate plating solution and copper oxide powder A used, as well as other equipment conditions, were the same as those used in the running test for investigating the concentration changes of additives described above.

[0052] Before copper embedding plating, the Si wafer was placed in a reduced pressure atmosphere, then pickled and washed with pure water, and copper embedding plating was performed on the vias. The plating conditions were: initial treatment current density 0.9A / dm 2 , 0.5mi, first stage treatment current density 0.9A / dm 2 , 19.5min, second stage treatment current density 1.36A / dm 2 The process took 14.6 min. The first stage corresponds to filling the vias, and the second stage corresponds to copper plating on the top of the vias.

[0053] Fig. 6 shows a cross-sectional observation photograph of a via after copper filling plating. It was confirmed that the inside of the via was completely filled with copper plating. It was found that the plating apparatus of this embodiment can reliably perform copper filling plating in a fine via with a diameter of 30 μm and a depth of 70 μm. [Explanation of symbols]

[0054] 1 Plating tank 11 Diaphragm 12 Plating tank inner wall 13 Liquid supply pipe 14 Annular flow path 15 Insoluble anode 2 Management tank 21 Upper lid 3 Anode solution tank 4 Copper oxide powder feeder 41 Powder Storage Room 42 Supply tube 43 Powder supply cylinder 44 Switching Device 45 Powder supply control device 5 Copper concentration adjustment tank 51 Upper lid U upper isolation room D Upper isolation room W Wafer G Carrier gas

Claims

1. a plating tank having an opening for placing an object to be plated, a liquid supply pipe for supplying a plating solution toward the object to be plated, an insoluble anode arranged to face the object to be plated, and a diaphragm for isolating the object to be plated and the insoluble anode, the diaphragm having an outer peripheral end fixed to an inner wall of the plating tank and a peripheral end of a through hole provided in the center of the diaphragm being fixed to the liquid supply pipe, such that an upward inclination is provided from the liquid supply pipe toward the outer periphery, The liquid supply pipe supplies the cathode plating solution from a control tank storing the cathode plating solution to an upper isolated chamber in the plating tank formed by the diaphragm and the placed object to be plated, In an insoluble anode plating apparatus, an anode solution is supplied from an anode solution tank storing the anode solution to a lower isolation chamber in a plating tank formed below a diaphragm, Average particle size: 25-40 μm, bulk density: 1.7 g / cm ３ the copper oxide powder is a granular copper oxide powder having an angle of repose of 10° to 12.5° in a mountain-shaped mass of copper oxide powder formed by dropping the copper oxide powder, and the copper oxide powder supplying means is configured to supply the copper oxide powder together with a carrier gas to a control tank via a supply tube that is configured not to generate static electricity; a powder supply cylinder from which static electricity has been removed is provided on the upper cover of the control tank, and a tip of the powder supply cylinder is disposed at a distance of 50 to 100 mm from the liquid surface so that the copper oxide powder supplied from the tip does not scatter into a space above the liquid surface of the cathode plating solution; 1. A plating apparatus for insoluble anodes, comprising: a supply tube connected to a powder supply cylinder.

2. a plating tank having an opening for placing an object to be plated, a liquid supply pipe for supplying a plating solution toward the object to be plated, an insoluble anode arranged to face the object to be plated, and a diaphragm for isolating the object to be plated and the insoluble anode, the diaphragm having an outer peripheral end fixed to an inner wall of the plating tank and a peripheral end of a through hole provided in the center of the diaphragm being fixed to the liquid supply pipe, such that an upward inclination is provided from the liquid supply pipe toward the outer periphery, A cathode plating solution is supplied from a control tank storing the cathode plating solution through a liquid supply pipe to an upper isolated chamber in the plating tank formed by the diaphragm and the placed object to be plated, In an insoluble anode plating apparatus, an anode solution is supplied from an anode solution tank storing the anode solution to a lower isolation chamber in a plating tank formed below a diaphragm, It is equipped with a copper concentration adjustment tank to adjust the copper concentration of the cathode plating solution. The copper concentration adjustment tank has an average particle size of 25 to 40 μm and a bulk density of 1.7 g / cm ３ The copper oxide powder is a granular copper oxide powder having an angle of repose of 10° to 12.5° in a mountain-shaped mass of copper oxide powder formed by dropping the copper oxide powder, and the copper oxide powder supply device conveys the copper oxide powder together with a carrier gas through a supply tube that is designed not to generate static electricity. a powder supply cylinder from which static electricity has been removed is provided on the upper cover of the copper concentration adjustment tank, and a tip of the powder supply cylinder is disposed at a distance of 50 to 100 mm from the liquid surface so that the copper oxide powder supplied from the tip does not scatter into the space above the liquid surface of the cathode plating solution; The copper concentration adjustment tank is provided with an agitation means for agitating the cathode plating solution, The supply tube is connected to the powder supply cylinder, and supplies copper oxide powder to the copper concentration adjustment tank to adjust the copper concentration of the cathode plating solution in the copper concentration adjustment tank; 1. An insoluble anode plating apparatus, comprising: a cathode plating solution having an adjusted copper concentration, the cathode plating solution being supplied from a copper concentration adjustment tank to a control tank.

3. 3. The plating apparatus for an insoluble anode according to claim 1, wherein the powder supply cylinder is made of a grounded titanium material or is connected to a static eliminator.

4. 3. The plating apparatus for an insoluble anode according to claim 1, wherein the carrier gas is nitrogen gas or argon gas.

5. 3. The insoluble anode plating apparatus according to claim 1, wherein the supply tube is provided with a switching means capable of switching between supplying a carrier gas and copper oxide powder and supplying only a carrier gas.

6. 3. The plating apparatus for an insoluble anode according to claim 1, wherein the supply tube has a powder flow meter for monitoring the supply state of the copper oxide powder, and is provided with powder supply control means for adjusting the supply amount of the copper oxide powder and controlling the stop of the supply.

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