JP2000273685A - Method and equipment for electroplating treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for electroplating treatment, capable of easily excluding the bubbles entering the via holes of a wafer, reducing the nonuniformity of plating, and improving manufacturing efficiency. SOLUTION: The equipment has a plating treatment tank where a wafer 1 is placed on a lower cup 20 and an upper cup 10 is fitted on the cup 20 from above to hermetically seal the inner part. A treatment solution supply pipe 14c for supplying a plating solution and a treatment solution discharge pipe 12a for discharging the plating solution are provided within the hermetically sealed upper cup 10. An evacuating means for evacuating the inside of the plating treatment tank and a pressurizing means for pressurizing the inside of the tank are provided to the treatment solution supply pipe 14c. The above means are provided with a valve 14f and a valve 14k, respectively, and the inside of the plating treatment tank is evacuated or pressurized, before performing plating treatment, by controlling the valves 14f, 14k to exclude the bubbles remaining at the plated surface of the wafer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic plating method and an electrolytic plating apparatus, and more particularly, to an electrolytic plating method and an electrolytic plating apparatus for performing plating wiring on a surface of a semiconductor wafer in a semiconductor manufacturing process. About.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a wiring process of forming a pattern and wiring between elements such as resistors and transistors formed in an IC chip of a semiconductor wafer is performed. In such a wiring process, wiring using aluminum (Al) is often used. In addition, it is known that in the case of LSI wiring, wiring using copper (Cu) is more excellent in low resistance than aluminum in wiring. Conventionally, as a method of wiring with a metal such as aluminum or copper, for example, an anode and a cathode are provided inside a plating tank, and a current is applied between the electrodes to form a metal layer on the surface of the semiconductor wafer. Electroplating apparatuses that perform wiring by wiring are well known. As such a conventional electrolytic plating apparatus, for example,
No. -6037. FIG. 5 is a configuration diagram showing the structure of such a conventional electrolytic plating apparatus. FIG. 6 is a cross-sectional view showing the surface of the wafer when a plating solution is supplied to the electrolytic plating apparatus shown in FIG.

As shown in FIG. 5, the conventional electrolytic plating apparatus includes an upper cup 30 having a cylindrical shape and an opening at the bottom, and a lower cup 40 fitted to the bottom surface of the upper cup 30 so as to be sealed. ing. Here, the lower cup 40
Is provided so that the wafer 1 to be plated can be placed on the upper surface. Also. The upper cup 30 includes a first cell 30a for accommodating the wafer 1 therein for plating, a second cell 30b for supplying a plating solution from above the first cell 30a, and a third cell 30c for discharging the plating solution. And The upper cup 30 has a processing liquid discharge pipe 30d for discharging a plating liquid on the upper surface, and a second cell 3 from the side.
0b is connected to a processing liquid supply pipe 30e that supplies a plating liquid.

At the bottom of the upper cup 30, there are provided a plurality of cathode contacts 38 which come into contact with the surface of the wafer 1 placed on the lower cup 40 with an appropriate elastic force. The upper cup 30 has a meshed anode 3 on the boundary surface between the first cell 30a and the second cell 30b.
6 and a saw hole 35 for supplying a plating solution. The anode 36 and the cathode contact part 38 are formed so as to be connected to the power supply 32 and to apply a voltage. Therefore, the cathode contact portion 38 is brought into contact with the surface of the wafer 1, whereby an electrical contact on the negative electrode side of the power supply 32 is obtained. The first cell 30a and the third cell 30c communicate with each other by providing a processing liquid outlet pipe 34.

[0005] In the case of performing electroplating by the conventional electroplating apparatus formed as described above, first, a circulating pump (not shown) is supplied from a processing solution supply tank (not shown).
The processing liquid supply pipe 30e provided in the upper cup 30
The plating solution is supplied into the second cell 30b via the. The plating solution is supplied to the pits 35 and the mesh-shaped anode 3.
6 and stored on the surface of the wafer 1 in the first cell 30a. After filling the inside of the first cell 30a, the plating solution flows from the anode 36 into the third cell 30c via the inside of the second cell 30b. Then, the plating liquid is discharged from a processing liquid discharge pipe 30d provided above the upper cup 30, and discharged to a processing liquid discharge tank (not shown) provided outside. After circulating the plating solution in this manner, a metal layer is formed on the surface of the wafer 1 by applying a current between the anode 36 and the cathode contact portion 38 (that is, the surface of the wafer 1).

According to the conventional electrolytic plating apparatus formed as described above, since the surface of the wafer 1 is plated in the closed upper cup 30, current leakage (leakage) occurs even when a plurality of processing tanks are provided. Precise plating can be performed without being affected by

However, in such a conventional electrolytic plating apparatus, when a plating solution is supplied to the inside, air remaining inside mixes to generate bubbles, and as shown in FIG. Via 1a between patterns formed in
Bubbles get inside. As described above, once bubbles enter the via 1a, it is difficult to remove the bubbles from the via 1a.

[0008]

As described above, in the conventional electrolytic plating apparatus, when the plating liquid is supplied from the processing liquid supply pipe 30e shown in FIG. The remaining air mixes with the plating solution to generate bubbles, and as shown in FIG.
a. When such bubbles are generated, it becomes difficult to discharge the bubbles from between the patterns, which causes plating unevenness on the surface of the wafer 1 and deteriorates the yield, and also makes it impossible to perform a precise plating process. Was. The present invention solves the above-described problems, and provides an electrolytic plating method and an electrolytic plating apparatus that can easily remove air bubbles that have entered a via of a wafer, reduce uneven plating, and improve manufacturing efficiency. With the goal.

[0009]

In order to solve the above-mentioned problems, an electroplating method according to the present invention is a plating method in which an object to be plated is placed at the bottom and a plating solution is supplied and discharged from above and circulated. A mesh electrode serving as an anode in the center of the tank, and a cathode contact pin electrode disposed at the bottom of the mesh electrode and in contact with the surface of the object to be plated. In the electroplating method of performing an electroplating process by applying a current to the plating process, the plating process is performed by disposing either or both of a depressurizing unit for depressurizing the inside of the bath and a pressurizing unit for pressurizing the inside of the bath in the plating bath. Before performing the plating process, either the pressure in the plating bath is reduced or increased, and then a certain amount of plating solution is supplied into the plating bath and left for a predetermined period of time. Comprising a rejection step of eliminating the bubbles remaining in the plating surface of the object. Here, the elimination step may be performed by immersing the object to be plated by performing a depressurization or a pressurization and then storing 1 mm to 100 mm from the bottom of the plating tank as a fixed amount of plating solution. preferable. In the removing step, it is preferable that bubbles are removed by leaving the plating solution in a plating tank for a fixed amount of 5 to 30 seconds. Further, the plating process, after performing the elimination step by either one of the pressure reducing means or the pressure means,
It is preferable that the plating process is performed by returning the inside of the plating bath once to the atmospheric pressure state. In addition, it is preferable that the decompression means is disposed in a supply unit that supplies a plating solution from above the plating tank. Preferably, the object to be plated is a semiconductor wafer to be plated and the bubbles are bubbles generated in vias between patterns formed on the surface of the semiconductor wafer. Further, it is preferable that the plating process is performed with a plating solution made of copper (Cu).

Further, the electrolytic plating apparatus according to the present invention has a plating tank in which an object to be plated is placed at the bottom and a plating solution is supplied and discharged from above to circulate the plating solution. And a contact pin electrode of a cathode installed on the bottom of the mesh electrode and in contact with the surface of the object to be plated, and an electrolytic plating process is performed by applying a current between the electrodes. In the plating apparatus, before performing the plating process by arranging one or both of the pressure reducing means for depressurizing the inside of the tank or the pressurizing means for pressurizing the inside of the tank in the plating tank, the pressure in the plating tank is reduced or After performing either one of the pressure treatments, supply a certain amount of plating solution into the plating tank and leave it for a predetermined time to leave air bubbles remaining on the plating surface of the object to be plated. It provided so as to eliminate. Here, in the plating tank, after performing either depressurization or pressurization, 1 mm from the bottom of the tank as a fixed amount of plating solution.
It is preferable that the object to be plated be immersed by storing the object to be plated to 100 mm. In addition, the object to be plated is stored in a plating tank with a certain amount of plating solution, and is immersed in the plating bath.
It is preferable to leave for 30 seconds to eliminate bubbles. Also,
In the plating treatment, it is preferable that after the elimination step is performed by one of the pressure reducing means and the pressure applying means, the inside of the plating treatment tank is once returned to the atmospheric pressure state to perform the plating treatment. In addition, it is preferable that the decompression means is disposed in a supply unit that supplies a plating solution from above the plating tank. Further, the plating tank has a lower cup on which the object to be plated is placed and moved up and down, and the lower cup is fitted at the raised position to house the object to be plated in a closed cavity, and a supply unit and a supply unit on the upper surface. An upper cup having a discharge portion for discharging a plating solution is provided. A support pin is provided which is urged by an elastic member to the lower cup to support the bottom of the object to be plated and abut against the contact electrode at a predetermined pressure. Is preferred. Also,
The object to be plated is a semiconductor wafer to be plated and wired,
The bubbles are preferably bubbles generated in vias between patterns formed on the surface of the semiconductor wafer. Further, the plating solution is preferably a plating solution made of copper (Cu).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an electrolytic plating apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a partially cutaway perspective view showing an embodiment of an electrolytic plating apparatus according to the present invention. Also,
FIG. 2 is a configuration diagram showing the internal structure of the electrolytic plating apparatus shown in FIG. FIG. 3 is a cross-sectional view showing the surface of the wafer when the pressure is reduced by the electrolytic plating apparatus shown in FIG. FIG. 4 is a sectional view showing the surface of the wafer when pressurized by the electrolytic plating apparatus shown in FIG.

As shown in FIG. 1, the plating apparatus according to the present invention is fitted with an upper cup 10 formed of an outer tank 12 and an inner tank 14 so as to hermetically seal the bottom surface of the upper cup 10. And a lower cup 20. here,
The outer tub 12 of the upper cup 10 is formed in a cylindrical shape and provided so as to extend in the vertical direction shown in FIG. 1, and has an upper end sealed at one end and an upper surface, and an opening at the bottom at the other end. Has been placed. The upper surface of the outer tub 12 is provided with a processing liquid discharge pipe 12a extending from the outside and connected thereto, and a processing liquid supply pipe 14c extending from the outside to the inside through the center of the upper surface. Further, the processing liquid supply pipe 14c is connected to an inner tank 14 arranged inside the outer tank 12 to supply a plating solution, and can reduce or pressurize the inside of the outer tank 12 and the inner tank 14 as described later. It is formed as follows.

The inner tub 14 extends in the front, rear, left and right directions shown in FIG. 1 in the outer tub 12, and is arranged so as to divide the inside of the tub into approximately half vertically. A cylindrical portion 14a extending cylindrically from the upper and lower surfaces and having an upper portion inclined in a conical shape and connected to the processing liquid supply pipe 14c is integrally formed. Further, a processing liquid discharge pipe 14d is connected to a lower side wall of the cylindrical portion 14a. This processing liquid discharge pipe 1
4d penetrates the side wall of the outer tub 12 and extends outward (see FIG. 2). Further, the inner tank 14 is formed such that the cylindrical portion 14a and the expanded portion 14b communicate with each other to form a hollow inside, and the lower end thereof is opened (see FIG. 2).
Here, a plurality of discharge holes 14 e (two locations in FIG. 1) that open to communicate with the outer tub 12 are provided above the expansion portion 14 b.
Is formed. Here, the outer cup 1 is provided in the upper cup 10.
A packing 18 made of a soft material formed in a ring shape is attached to a lower portion where the inner tank 14 and the inner tank 14 are in contact with each other. A plurality of (two in FIG. 1) contact pin electrodes 16 are provided on the packing 18 so as to extend from the outside of the outer tub 12 to the inside and penetrate from the top to the bottom of the packing 18.

On the other hand, the lower cup 20 is formed by a pedestal 24 that protrudes in a columnar shape at the center and on which the wafer 1 is mounted, and a discharge cup 28 that is disposed at the bottom of the pedestal 24. Here, the discharge cup 28 is formed in a cylindrical shape and has a bottom surface, and the pedestal 24 is arranged at the upper center of the bottom surface. The pedestal 24 is connected to the outer tub 12
A lower pedestal 24b having the same diameter as that of the lower pedestal 24b and an upper pedestal 24a having a smaller diameter and projecting in a columnar shape from the upper portion of the lower pedestal 24b are integrally formed. And
A ring-shaped packing 26 made of a soft material is mounted on the upper end of the lower pedestal 24b. Further, the lower pedestal 24b is provided with support pins 22 (three places in FIG. 1) mounted on the upper surface so as to be urged by a spring (not shown) to expand and contract in the vertical direction.

As shown in FIG. 2, the lower cup 20 is provided so as to be vertically moved up and down as shown in FIG. . When the lower cup 20 is raised and fitted to the bottom surface of the upper cup 10 in this manner, the wafer 1 can be brought into close contact with the packing 18 of the upper cup 10 by the support pins 22 urged by a spring. Also,
When the lower cup 20 and the upper cup 10 are fitted, the inside of the upper cup 10 can be sealed by the packing 26 mounted on the pedestal 24. Therefore, packings 18, 2
6 can prevent the plating solution supplied to the inside of the upper cup 10 from leaking.

The drain cup 28a of the lower cup 20 is connected to a drain pipe 28a extending cylindrically from below. The drain tube 28a is connected to a discharge tank (not shown) for discharging a plating solution provided outside. Further, inside the outer tank 14 of the upper cup 10, a rectifying plate 14 g disposed in the center and a mesh electrode 14 h serving as an anode electrode mounted below the rectifying plate 14 g are provided.
Are provided. As a result, when the lower cup 20 and the upper cup 10 are fitted, the contact pin electrode 16 mounted on the packing 18 comes into contact with the wafer 1, and a voltage is applied between the contact pin electrode 16 and the mesh electrode 14h. The metal layer is formed on the surface of the wafer 1 by electrolytic plating. In addition, the processing liquid discharge pipes 12a and 14d and the processing liquid supply pipe 14c connected to the upper cup 10 include:
Valves 12b, 14f and 14i are mounted respectively.

The processing liquid supply pipe 14c is connected to a plating liquid storage tank storing a plating liquid and a pressurizing device (not shown) for supplying compressed air to a pipe provided with a valve 14f. ing. In addition, the processing liquid supply pipe 14c includes:
An exhaust pipe 14j for reducing the pressure inside the upper cup 10 is connected. The exhaust pipe 14j is provided with a valve 14k for adjusting the amount of air to be reduced. Thus, as described above, the processing liquid supply pipe 14c is formed so that the inside of the upper cup 10 can be pressurized or depressurized while supplying the plating liquid. Further, the processing solution discharge pipes 12a, 1
Although not shown, the above-mentioned plating solution storage tank is connected to 4d.

Therefore, in the electrolytic plating apparatus according to the present invention, the plating solution is supplied from the upper portion of the upper cup 10 and discharged from the upper portion again, thereby plating the surface of the wafer 1 in the same manner as the prior art shown in FIG. The liquid can be circulated,
Unlike the prior art shown in FIG. 5, the inside of the upper cup 10 is formed so as to be pressurized or decompressed.

When using the thus formed electrolytic plating apparatus according to the present invention, first, as shown in FIG. 2, the wafer 1 is placed on three support pins 22 projecting above the pedestal 24. I do. When the wafer 1 is placed on the support pins 22, the lower cup 20 is lifted upward as shown in FIG. 1 and fitted until the bottom of the upper cup 10 is sealed by the packings 18 and 26. At this time, the pattern surface of the wafer 1 contacts the tip of the contact pin electrode 16.

Next, unlike the prior art shown in FIG. 5, the electrolytic plating apparatus according to the present invention executes an elimination step for eliminating bubbles remaining in the vias of the wafer 1 before performing the electrolytic plating. . This elimination process is performed on the upper cup 1
It is executed by performing either one of the pressure reduction or the pressure increase in the inside of 0. First, in the elimination step by depressurization, the lower cup 20 is fitted to the bottom of the upper cup 10 and hermetically closed, and the inside is depressurized by closing the valves 12b, 14f, and 14i and opening the valve 14k. After the decompression is completed, the valve 14k is closed and the valve 14f is opened to supply a constant amount of the plating solution into the upper cup 10. Thereafter, the valve 14f is closed and left for a predetermined time while the plating solution is stored in the upper cup 10 in a fixed amount. At this time, air is mixed with the plating solution 2 supplied through the valve 14f on the surface of the wafer 1, and the bubbles 3 enter the vias 1a formed between the patterns as shown in FIG. I will. However, since the inside of the upper cup 10 is depressurized on the surface of the wafer 1, the via 1a
The air bubbles 3 that have entered inside are eliminated in the direction of the arrow shown in FIG. 3, and the voids in the via 1a are eliminated, so that normal plating can be performed. Thereafter, the wafer 1 that has been subjected to the elimination step by the reduced pressure is returned to the atmospheric pressure state and the electrolytic plating is performed.

On the other hand, in the removing step by pressurization, the valves 12b, 14k, and 14i are closed and the valve 14 is closed while the lower cup 20 is fitted to the bottom of the upper cup 10 and sealed.
By opening f, compressed air is supplied and pressurized. After the pressurization is completed, a predetermined amount of the plating solution is supplied into the upper cup 10 from the valve 14f. Thereafter, the valve 14f is closed and left for a predetermined time while the plating solution is stored in the upper cup 10 in a fixed amount. At this time, air mixes with the plating solution supplied via the valve 14f on the surface of the wafer 1 and bubbles enter the vias 1a formed between the patterns as shown in FIG. However, on the surface of the wafer 1, since the inside of the upper cup 10 is pressurized, the plating solution 2 is pushed into the via 1a by pressure in the direction of the arrow shown in FIG. Gaps are eliminated and normal plating can be performed. Thereafter, the wafer 1 that has been subjected to the elimination step by the reduced pressure is returned to the atmospheric pressure state and the electrolytic plating is performed.

Here, in the elimination step, the wafer 1 is immersed by supplying a certain amount of plating solution after performing either pressure reduction or pressure application and storing it from the bottom in the upper cup 10 by about 1 mm to 100 mm. It is preferable to execute it. In the removing step, it is preferable that bubbles are removed by leaving the plating solution in the upper cup 10 for about 5 to 30 seconds in a state of being stored.

As described above, the electrolytic plating apparatus according to the present invention differs from the prior art shown in FIG. 5 in that an elimination step is performed to eliminate bubbles remaining in the vias of the wafer 1 before performing the electrolytic plating processing. It is formed so that it can be executed. Then, when the elimination step is completed as described above, the valve 14 shown in FIG.
i and 14k are closed and the valves 12b and 14f are opened to return to the atmospheric state, and the plating solution is supplied into the inner tank 14 from the processing solution supply pipe 14c. As a result, the plating solution is transferred to the inner tank 1
4 and filled into the outer tub 12 through the discharge hole 14e. When the outer tank 12 is filled with the plating solution, the plating solution overflows from the processing solution discharge pipe 12a and is discharged to a plating tank (not shown).

Therefore, the plating solution is supplied into the inner tank 14 through the processing solution supply pipe 14c, and is circulated by being discharged through the processing solution discharge pipe 12a. After circulating the plating solution in the upper cup 10 in this manner, the mesh electrode 1
By applying a voltage between the contact pin 4h and the contact pin electrode 16 and energizing the current, a current is supplied through the contact pin electrode 16 in contact with the wafer 17, and the electrolytic plating is performed.

After the electrolytic plating process is completed, the energization and the supply of the plating solution are stopped, and the processing solution supply pipe 1 is turned off.
The valve 14f of 4c is closed. On the other hand, when the valve 14i is opened, the plating solution remaining in the cup is discharged to a plating tank (not shown) via the processing solution return pipe 14d. When the plating liquid in the upper cup 10 becomes small and the flow of the plating liquid discharged from the processing liquid return pipe 14d stops, the valve 14f is opened to open the processing liquid supply pipe 14c.
To supply the compressed solution so that the plating solution does not remain in the upper cup 10 and discharge the plating solution.

When the plating solution is pumped and discharged, the lower cup 20 is lowered to take out the electrolytically plated wafer 1 from the pedestal 24. At this time, a small amount of the plating solution remaining inside the upper cup 10 and the lower cup 20 flows down to the discharge cup 28 of the lower cup 20, and is discharged to a drain tank (not shown) via the drain pipe 28a.

As described above, according to the electrolytic plating method and the electrolytic plating apparatus according to the present invention, air bubbles can be effectively removed from the surface of the wafer by reducing or increasing the pressure in the cup. It is possible to improve the manufacturing efficiency by reducing the unevenness of plating while performing the process.

The embodiments of the electrolytic plating method and the electrolytic plating apparatus according to the present invention have been described above in detail. However, the present invention is not limited to the above-described embodiments, and does not depart from the gist of the present invention. Can be changed with. For example, the embodiment in which the electroplating apparatus according to the present invention is applied to a wiring process of a semiconductor wafer has been described. However, the present invention is not limited to this, and can be used for an apparatus having a wiring process such as a circuit board and a CD. is there.

[0029]

As described above, according to the electroplating method and the electroplating apparatus of the present invention, before performing the plating process, the discharge step by either the pressure reduction or the pressurization is executed, and the semiconductor wafer is processed. Since the air bubbles which have entered between the patterns can be easily discharged, the unevenness in plating can be prevented, the yield in the production process can be improved, and precise plating can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view, partially cut away, showing an embodiment of an electrolytic plating apparatus according to the present invention.

FIG. 2 is a configuration diagram showing an internal structure of the electrolytic plating apparatus shown in FIG.

FIG. 3 is a sectional view showing the surface of the wafer when the pressure is reduced by the electrolytic plating apparatus shown in FIG. 1;

FIG. 4 is a sectional view showing the surface of the wafer when pressurized by the electrolytic plating apparatus shown in FIG. 1;

FIG. 5 is a configuration diagram showing the structure of a conventional electrolytic plating apparatus.

FIG. 6 is a sectional view showing the surface of the wafer when a plating solution is supplied to the electrolytic plating apparatus shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 10 Upper cup 12 Outer tank 12a Processing liquid return pipe 12b Valve 14 Inner tank 14a Cylindrical part 14b Expansion part 14c Processing liquid supply pipe 14d Processing liquid return pipe 14e Discharge hole 14f Valve 14g Rectifying plate 14h Mesh electrode 14i Valve 16 Contact pin Electrode 18 Packing 20 Lower cup 22 Support pin 24 Pedestal 24a Upper pedestal 24b Lower pedestal 26 Packing 28 Discharge cup 28a Drain pipe

Claims (15)

[Claims] 1. A plating tank having an object to be plated placed at a bottom thereof, and a plating solution supplied and discharged from above to circulate by supplying a plating solution from above. And a cathode contact pin electrode which is disposed at the bottom of the substrate and which is in contact with the surface of the object to be plated, and which performs an electrolytic plating process by applying a current between the electrodes. Before the treatment of performing the plating treatment by disposing either or both of the pressure reducing means for depressurizing the inside of the tank and the pressurizing means for pressurizing the inside of the tank, the inside of the plating tank may be either depressurized or pressurized. After performing, a removing step of removing bubbles remaining on the plating surface of the object to be plated by supplying a certain amount of the plating solution into the plating bath and leaving it for a predetermined time. Electrolytic plating processing method according to claim that there were example. 2. The electrolytic plating method according to claim 1, wherein, in the removing step, after performing one of the reduced pressure and the increased pressure, the fixed amount of the plating solution is removed from the bottom in the plating tank. An electrolytic plating method, characterized in that the object to be plated is immersed and stored by storing it in a range of 1 mm to 100 mm. 3. The electrolytic plating method according to claim 1, wherein, in the removing step, bubbles are eliminated by leaving the plating tank in a constant amount for 5 to 30 seconds while storing a certain amount of plating solution. An electrolytic plating method comprising: 4. The electroplating method according to claim 1, wherein in the plating process, after the removing step is performed by one of the depressurizing unit and the pressurizing unit, the inside of the plating bath is increased once. An electrolytic plating method characterized by performing a plating process by returning the pressure to an atmospheric pressure. 5. The electrolytic plating method according to claim 1, wherein the depressurizing means is provided in a supply unit for supplying the plating solution from above the plating tank. Method. 6. The electrolytic plating method according to claim 1, wherein the object to be plated is a semiconductor wafer to be plated and the bubbles are generated in vias between patterns formed on the surface of the semiconductor wafer. An electrolytic plating method characterized by being bubbles. 7. The electrolytic plating method according to claim 1, wherein the plating is performed with the plating solution made of copper (Cu). 8. A plating tank having an object to be plated placed at the bottom thereof, for supplying and discharging a plating solution from above, and circulating the plating liquid. A mesh electrode serving as an anode is provided in the center of the tank, and the mesh electrode is provided at the center thereof. And a cathode contact pin electrode which is disposed at the bottom of the substrate and which is in contact with the surface of the object to be plated, and which performs an electrolytic plating process by applying a current between the electrodes. Before the treatment of performing the plating treatment by disposing either or both of the pressure reducing means for depressurizing the inside of the tank and the pressurizing means for pressurizing the inside of the tank, the inside of the plating tank may be either depressurized or pressurized. After performing, a predetermined amount of the plating solution is supplied into the plating tank and left for a predetermined time to remove bubbles remaining on the plating surface of the object to be plated. Electrolytic plating apparatus, characterized in that. 9. The electrolytic plating apparatus according to claim 8, wherein, after performing one of the decompression and the pressurization in the plating tank, the fixed amount of the plating solution is applied from the bottom of the tank. An electrolytic plating apparatus, wherein the object to be plated is immersed by storing it in a range of 1 mm to 100 mm. 10. The electrolytic plating apparatus according to claim 8, wherein the object to be plated is left for 5 to 30 seconds in a state where a certain amount of plating solution is stored and immersed in the plating tank. An electrolytic plating apparatus characterized in that air bubbles are eliminated by removing the bubbles. 11. The electroplating apparatus according to claim 8, wherein in the plating process, after the removing step is performed by one of the depressurizing unit and the pressurizing unit, the inside of the plating bath is once enlarged. An electrolytic plating apparatus characterized by performing a plating process by returning to an atmospheric pressure state. 12. The electrolytic plating apparatus according to claim 8, wherein the pressure reducing means is provided in a supply unit for supplying the plating solution from above the plating tank. apparatus. 13. The electrolytic plating apparatus according to claim 8, wherein the plating tank is fitted with a lower cup for placing the object to be plated and moving up and down, at a position where the lower cup is raised. The object to be plated is housed in a closed cavity and formed on the upper surface by an upper cup provided with the supply section and a discharge section for discharging the plating solution. An electroplating apparatus comprising: a support pin for supporting a bottom of a plating object and abutting the contact electrode at a predetermined pressure. 14. The electrolytic plating apparatus according to claim 8, wherein the object to be plated is a semiconductor wafer to be plated and the bubbles are generated in vias between patterns formed on the surface of the semiconductor wafer. An electrolytic plating apparatus characterized by being bubbles. 15. The electrolytic plating apparatus according to claim 8, wherein the plating solution is a plating solution made of copper (Cu).