JP2001020091A - Plating device and plating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating device and a plating method capable of plating at a high speed by increasing the relative velocity between the surface of a substrate to be plated and a plating liquid to form a plated coating film uniform through the whole surface. SOLUTION: The plating surface of the substrate W to be plated, which is held by a substrate rotation holding means 50, is brought into contact with a plating liquid in a plating vessel 10 and an anode 30 is mounted to face the substrate W to be plated. The turning flow in the direction opposed to the rotating direction of the substrate W to be plated is generated in the plating liquid between the substrate W to be plated and the anode 30 by moving the plating liquid supplied from a plating liquid supply pipe 15 to the plating vessel 10 in the eccentric direction to the center of the plating vessel 110. The addition of the action of the flow of the plating liquid and the rotation of the substrate W to be plated to each other results in the increase in the relative velocity of the plating liquid on the surface of the plating surface of the substrate W to be plated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus and a plating method suitable for plating a substrate to be plated such as a semiconductor wafer.

[0002]

2. Description of the Related Art In recent years, a metal plating apparatus such as copper plating has been used to fill a groove or a hole of a substrate to be plated having a fine groove or hole for wiring formed on a surface of a semiconductor wafer or the like. A method of filling the grooves and holes by plating is adopted. Conventionally, as this type of plating apparatus, there is a face down type jet plating apparatus. This plating apparatus is shown in FIGS.
As shown in FIG. 5, a substrate W to be plated such as a semiconductor wafer is placed on a substrate holding part 220 with a surface to be plated facing downward on a plating tank 200, and a plating solution in a plating solution storage tank 203 is pumped by a pump 205. With the plating solution supply pipe 207
13 through the bottom of the plating tank 200, and the holes or meshes (holes in FIG.
In this case, plating is performed by applying a jet of a plating solution perpendicularly to the surface to be plated of the substrate to be plated W through a mesh).

The plating solution overflowing the plating bath 200 is collected by a plating solution receiver 209 disposed outside the plating bath 200 and returned to the plating solution storage tank 203. By applying a predetermined voltage E between the anode plate 211 and the substrate W to be plated, a plating current flows between the anode plate 211 and the substrate W to be plated, and a plating film is formed on the surface of the substrate W to be plated. You.

However, in the above conventional jet-type plating apparatus, the relative velocity between the surface of the substrate W and the plating solution is obtained by the flow velocity at which the jet strikes the surface of the substrate W and flows in the outer peripheral direction. The speed was not uniform over the entire surface of the substrate W to be plated, and the relative speed itself did not become sufficiently high.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to increase the relative speed between a surface of a substrate to be plated and a plating solution to thereby increase the concentration near the surface of the substrate to be plated. An object of the present invention is to provide a plating apparatus and a plating method that prevent supply from being rate-determined by reducing the thickness of a diffusion layer, form a uniform plating film on the entire surface, further increase current density, and enable high-speed plating. .

[0006]

According to a first aspect of the present invention, to solve the above-mentioned problems, the surface to be plated of the substrate to be plated held by the substrate rotation holding means is brought into contact with a plating solution in a plating bath. In addition, in a plating apparatus in which an anode electrode is provided so as to face the substrate to be plated, a swirling flow is generated in a plating solution between the substrate to be plated and the anode electrode in a direction opposite to the rotation direction of the substrate to be plated. It is characterized in that a means for causing it to be provided is provided. Thereby, the flow of the plating solution and the rotation of the substrate to be plated are added, and the relative speed of the plating solution on the surface to be plated of the substrate to be plated can be increased.

According to a second aspect of the present invention, a substrate to be plated and an anode electrode are opposed to each other via a plating solution, and a current is applied between the substrate to be plated and the anode electrode while rotating the substrate to be plated. In the plating method for plating a surface to be plated, in the plating, a plating solution between the substrate to be plated and the anode electrode, wherein a swirling flow is generated in a direction opposite to the rotation direction of the substrate to be plated. .

According to a third aspect of the present invention, the means for generating a swirling flow in the plating solution is a plating solution supply pipe for supplying the plating solution into the plating bath in a direction eccentric from the center of the plating bath. It is characterized by:

According to a fourth aspect of the present invention, the means for generating a swirling flow in the plating solution is constituted by a rotating object installed in the plating solution and rotating, or a means for rotating the anode electrode itself. It is characterized by comprising.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall schematic configuration diagram showing a plating apparatus according to one embodiment of the present invention. As shown in the figure, in this plating apparatus, an anode plate (anode electrode) 30 is installed at the center of the bottom of the plating tank 10, and a semiconductor wafer (substrate to be plated) W is positioned at the plating solution level of the plating tank 10. The semiconductor wafer W is held by the substrate holding portion 60 of the substrate rotating / holding means 50 in such a manner. Hereinafter, each component will be described.

FIG. 2 is a plan view showing the plating tank 10. As shown in FIGS. 1 and 2, the plating tank 10 is a substantially cylindrical container having an open upper surface, and is configured by attaching a plating solution supply pipe 15 to a side wall thereof. The plating solution supply pipe 15 is attached such that the direction in which the plating solution is jetted into the plating tank 10 is directed eccentrically from the central axis of the plating tank 10.
Of the plating bath 10 by the flow of the plating solution supplied from the
The internal plating solution is configured to generate a swirling flow in a certain direction.

A plating solution receiver 11 is provided on the outer periphery of the upper edge of the plating bath 10 so as to surround the plating bath. The plating solution in the plating solution receiver 11 is configured to be injected into the plating bath 10 from the plating solution supply pipe 15 via the plating solution storage tank 13, the pump 16 and the filter 17.

The anode plate 30 is formed of a disk having substantially the same size as the surface to be plated of the semiconductor wafer W. In the case of copper plating, a plating solution based on copper sulfate and an anode plate (soluble anode plate) of phosphorous copper are generally used, but an insoluble anode plate may be used. The anode plate 30 and the semiconductor wafer W are installed in parallel.

On the other hand, the substrate rotating and holding means 50 is provided above the substrate holding part 60 with a substrate holding part vertical drive mechanism 51 for elevating the substrate holding part 60, and a substrate pressing plate up and down for raising and lowering a substrate holding plate 67 described below. A drive mechanism 53 and a motor (rotation drive mechanism) 55 are provided. The substrate presser plate vertical drive mechanism 53 is constituted by a cylinder driven by a spring force in a downward direction and by air in an upward direction, and is accommodated in a frame 53 a supported by a rotation shaft of a motor 55. The motor 55 and the board holding plate vertical drive mechanism 53 are housed in the frame 51a,
1a is fixed to the support arm 59. The substrate holding unit vertical drive mechanism 51 fixed to the upper part of the frame 51a moves the motor 55 up and down, whereby the substrate holding plate up and down drive mechanism 53 and the substrate holding unit 60 are simultaneously moved up and down.

FIG. 3 is a sectional view showing a portion of the substrate holding portion 60, and FIG. 4 is an enlarged sectional view of a main portion when the substrate holding portion 60 is viewed from a direction orthogonal to FIG. FIG. 3 is an enlarged sectional view of a main part of a seal member 71. As shown in these figures, the substrate holder 60 has a semiconductor wafer W inside.
A cylindrical shape having a diameter slightly larger than the diameter of the wafer capable of storing the substrate, the lower surface thereof has an opening having a diameter slightly smaller than the diameter of the wafer, the upper portion is closed, and the rotation of the substrate holding portion supporting the substrate holding portion 60 at the center of the upper surface. Shaft (fixed to the frame 53a)
A substrate holding case 65 made of an insulating material having a slit-shaped opening 63 for taking in and out the semiconductor wafer W on the side wall of the substrate holding case 61, and disposed in the substrate holding case 65 and having a diameter substantially equal to the diameter of the wafer. And a disk-shaped substrate holding plate 67. The board holding plate 67 is made of an insulating material,
A holding shaft 69 for moving the substrate holding plate 67 up and down is provided at an upper portion. The holding shaft 69 extends upward through the inside of the substrate holding unit rotating shaft 61 and serves as an axis of the substrate holding plate vertical drive mechanism 53. A ring-shaped seal member 71 is provided around the opening on the lower surface of the substrate holding case 65, and the seal member 71 is in close contact with the surface of the semiconductor wafer W to prevent the plating solution from entering. A plurality of or ring-shaped cathode pins 73 are provided inside the lower surface of the substrate holding case 65 on the side having a larger diameter than the seal member 71 so that the cathode pins 73 abut on the outer peripheral portion of the surface of the semiconductor wafer W. Semiconductor wafer W
In order to make the potential of the surface to be plated uniform, the cathode pins 73 are closely arranged in a shape such that the cathode pins 73 are in contact with the entire outer periphery of the surface of the semiconductor wafer W.
The cathode pins 73 may be formed of a ring-shaped plate so as to make line contact with the semiconductor wafer W, and the inner peripheral portion may be bent toward the semiconductor wafer W to have elasticity. As shown in FIG. 5, an air passage 65b is provided so as to connect the inside and the outside of the peripheral edge portion 65a holding the semiconductor wafer W below the substrate holding case 65.

On the other hand, the substrate holder 60 is
1 and is moved up and down by a substrate holder vertical drive mechanism 51 shown in FIG.
At this position, the plated semiconductor wafer W is not touched by the plating solution. At this position, the plated semiconductor wafer W is taken out and the unprocessed semiconductor wafer W is mounted. On the other hand, at the lowered position, the surface to be plated of the semiconductor wafer W is a position where it is immersed in the plating solution.

When the semiconductor wafer W is taken out of the substrate holding part 60, the substrate holding part 60 is raised to a position where it does not come into contact with the plating solution, and the substrate holding plate 67 is moved to the position shown by the dotted line in FIG. After that, the robot hand 75 is inserted through the opening 63 of the substrate holding case 65 as shown in FIG. 4, the back surface of the semiconductor wafer W is sucked by vacuum suction, and the semiconductor wafer W is taken out from the opening 63. On the other hand, when inserting and holding the semiconductor wafer W into the substrate holding unit 60, the untreated semiconductor wafer W is vacuum-adsorbed by the robot hand 75 with the surface to be plated down, and the substrate holding case 65 is Semiconductor wafer W inside
, The vacuum suction of the robot hand 75 is released, and the robot hand 75 is placed on the sealing member 71 and the cathode pin 73. The robot hand 75 is pulled out from the opening 63, and the substrate pressing plate 67 is lowered to move the robot hand 75 over the semiconductor wafer W. Is pressed down to securely contact the seal member 71 and the cathode pin 73. The vertical movement of the substrate pressing plate 67 is performed by the substrate pressing plate vertical drive mechanism 53 shown in FIG. The central portion of the opening 63 is largely open to allow the robot hand 75 to pass through.

When copper is electrolytically plated on the surface of the semiconductor wafer W, since copper is easily diffused into silicon, Ti (titanium), Ta (tantalum), and TiN are formed as barrier layers on the surface of the wafer surface to be plated. (Titanium nitrite), metal such as TaN (tantalum nitrite), WN (tungsten nitrite) or a compound thereof, and a barrier layer or a copper layer thinly formed on the barrier layer as a cathode; Electroplating is performed by energizing the plate 30 as an anode.

When the plating solution comes into contact with the cathode pins 73 for supplying power to the semiconductor wafer W, a plating layer is also deposited on the cathode pins 73 and the plating layer near the cathode pins 73 is damaged when the semiconductor wafer W is taken out. Since the danger is high, when the semiconductor wafer W is held by the substrate holding unit 60, the outer periphery of the surface to be plated of the semiconductor wafer W is sealed with the sealing member 71 so that the plating solution does not come into contact, and the cathode pins 73 are held on the substrate. The semiconductor wafer W is brought into contact with the surface of the semiconductor wafer W in a space that does not come into contact with the plating solution formed by the case 65, the semiconductor wafer W, and the seal member 71.

Next, a method of performing plating in the plating layer 10 using the plating apparatus shown in FIG. 1 will be described.

First, after the unprocessed semiconductor wafer W is mounted on the substrate holder 60, the pump 16 is driven to drive the plating solution in the plating solution storage tank 13 through the filter 17 from the plating solution supply pipe 15 into the plating tank 10. Supply.

On the other hand, while rotating the substrate holding unit 60 at a predetermined number of revolutions by the motor 55, the substrate holding unit 60 descends until the semiconductor wafer W comes into contact with the plating solution surface of the plating tank 10, and electricity is supplied between the semiconductor wafer W and the anode plate 30. Performs electrolytic plating on the surface to be plated of the semiconductor wafer W.

At this time, the direction of the plating solution supplied from the plating solution supply pipe 15 into the plating bath 10 is eccentric from the central axis of the plating bath 10 as described above. A swirling flow is generated in the plating solution. On the other hand, the semiconductor wafer W is rotating together with the substrate holding unit 60 so as to be opposite to the rotation direction of the swirling flow. That is, in FIG. 1, the plating solution is counterclockwise and the semiconductor wafer W is clockwise as viewed from above. For this reason, the relative speed between the plating surface of the semiconductor wafer W and the plating solution increases, the concentration diffusion layer near the surface of the plating surface can be thinned, and the plating film can be made uniform and the plating speed can be increased.

The plating solution supplied from the plating solution supply pipe 15 overflows from the upper edge of the plating bath 10, is collected in the plating solution receiver 11, flows into the plating solution storage tank 13 through the pipe 14, and is pumped. By 16, it is again supplied to the plating tank 10 and circulated.

FIG. 6 is a view showing a plating apparatus according to another embodiment of the present invention. In this embodiment, FIG.
The point different from the embodiment shown in FIG. 1 is that a plating solution supply pipe 70 for ejecting a plating solution into the plating tank 10 from the center of the bottom surface of the plating tank 10 is attached. This plating solution supply pipe 7
0 is provided with a nozzle portion 71 at its tip,
Is provided so as to pass through the center of the anode plate 30.

FIG. 7 is an enlarged view of the nozzle portion 71. FIG. 7 (a) is a plan view, and FIG. 7 (b) is a view (a).
FIG. 2 is a schematic sectional view taken along line AA of FIG. As shown in the figure, the nozzle unit 71 is provided with a plurality of direction-changing fins 73 that are obliquely inclined point-symmetrically about the center of the plating solution supply pipe 70,
Thereby, the direction of the plating solution ejected from the nozzle portion 71 is set to a diagonally upward direction counterclockwise when viewed from above the plating tank 10, thereby generating a swirling flow that rotates counterclockwise. The fact that the semiconductor wafer W is rotating clockwise is the same as in the previous embodiment. Therefore, even with this configuration, similar to the embodiment shown in FIG.
The relative speed between the plating surface of the semiconductor wafer W and the plating solution increases, the concentration diffusion layer near the surface of the plating surface can be thinned, and the plating film can be made uniform and the plating speed can be increased.

The reference numerals 80 and 80 shown in FIG.
The piping 80 is a pipe for circulating the plating solution from the bottom surface of the plating solution to the plating solution storage tank 13. A valve 81 and a filter 83 are attached to these pipes 80.

The tip of the plating solution supply pipe 70 projecting from the anode plate 30 is made of a non-metallic material so as not to disturb the electric field. By providing the small anode portion 30a at the center of the inside of the plating solution supply pipe 70, the state of the electric field when the anode plate has no holes is brought as close as possible.

FIG. 8 is a view showing a plating apparatus according to another embodiment of the present invention. FIG. 9 is a plan view of the plating tank 10. This embodiment is different from the embodiment shown in FIG. 1 in that the plating solution is jetted from a plurality of (four in this embodiment) plating solution supply pipes 90 from the periphery of the bottom surface of the plating tank 10. Is a point. As shown in FIG. 9, the spraying direction of each plating solution supply pipe 90 is a direction decentered by a predetermined angle from the central axis of the plating tank 10 obliquely above. By injecting the plating solution in this manner, a swirling flow having a counterclockwise rotation when viewed from above is generated in the plating solution in the plating tank 10. At this time, if the semiconductor wafer W is rotated clockwise, the relative speed between the plating surface of the semiconductor wafer W and the plating solution is increased, and the concentration diffusion layer near the surface of the plating surface is thinned, as in the above embodiments. Therefore, the plating film can be made uniform and the plating speed can be increased.

A pipe 91 for circulating the plating solution from the center of the bottom of the plating tank 10 to the plating solution storage tank 13 is provided with a valve 93 and a filter 95. I have.

FIG. 10 is a view showing a plating apparatus according to still another embodiment of the present invention. In this embodiment, the difference from the plating apparatus shown in FIG. 1 is that instead of directing the spraying direction of the plating solution supply pipe 15 to a direction eccentric from the center axis of the plating tank 10 by a predetermined angle, the semiconductor wafer W and the anode plate 30 The point is that a rotating object (means for generating a swirling flow of the plating solution) 101 is disposed between them. In this embodiment, the rotating object 101 is connected to a motor 105 through a shaft 103 that penetrates the center of the anode plate 30, and the motor 105 rotates the rotating object 101 in a direction opposite to the rotation direction of the semiconductor wafer W. A swirling flow of the plating solution is generated in a direction opposite to the rotation direction of the semiconductor wafer W. Even with such a configuration, the relative speed between the plating surface of the semiconductor wafer W and the plating solution increases, as in the above-described embodiments, so that the plating film can be made uniform and the plating speed can be increased.

FIG. 11 is a view showing a plating apparatus according to still another embodiment of the present invention. This embodiment is different from the plating apparatus shown in FIG.
Instead of rotating 01, the anode plate 30 itself is configured to be rotated by a motor 105 as means for generating a swirling flow of the plating solution. Even with such a configuration, it is possible to generate a swirling flow of the plating solution in a direction opposite to the rotation direction of the semiconductor wafer W, and as in each of the above embodiments,
The relative speed between the plating surface of the semiconductor wafer W and the plating solution is increased, so that the plating film can be made uniform and the plating speed can be increased.

In the above embodiment, the semiconductor wafer W is used as the substrate to be plated. However, it goes without saying that the present invention may be used for plating various other substrates.

Various other methods are conceivable as means for rotating the plating solution in the plating tank. In short, means for generating a swirling flow of the plating solution in a direction opposite to the rotation direction of the substrate to be plated is provided. Any structure may be used. Needless to say, the mechanism for rotating and holding the substrate can be variously changed.

[0035]

As described above in detail, according to the present invention, the relative speed between the plating surface of the substrate and the plating solution can be increased, and the concentration diffusion layer near the plating surface can be made thin. This has an excellent effect that the plating film can be made uniform and the plating speed can be increased.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram showing a plating apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a plating tank 10.

FIG. 3 is a cross-sectional view illustrating a portion of a substrate holding unit 60.

FIG. 4 is an enlarged sectional view of a main part when the substrate holding unit 60 is viewed from a direction orthogonal to FIG.

FIG. 5 is an enlarged sectional view of a main part of the seal member 71.

FIG. 6 is a view showing a plating apparatus according to another embodiment of the present invention.

FIGS. 7A and 7B are enlarged views of the nozzle portion 71. FIG. 7A is a plan view, and FIG. 7B is a schematic cross-sectional view taken along line AA of FIG.

FIG. 8 is a view showing a plating apparatus according to another embodiment of the present invention.

9 is a plan view of the plating tank 10 shown in FIG.

FIG. 10 is a view showing a plating apparatus according to another embodiment of the present invention.

FIG. 11 is a view showing a plating apparatus according to another embodiment of the present invention.

FIG. 12 is a view showing a conventional plating apparatus.

FIG. 13 is a view showing a conventional plating apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Plating tank 15 Plating solution supply pipe (means for generating a swirling flow of plating solution) 30 Anode plate (anode electrode) 50 Substrate rotation holding means 60 Substrate holding part W Semiconductor wafer (substrate to be plated) 101 Rotating object (Plating solution Means for generating swirling flow)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Chiyo 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Works Co., Ltd. (72) Inventor Kenya Tomioka 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Inside the Ebara Works (72) Katsumi Tsuda 11-1, Haneda Asahimachi, Ota-ku, Tokyo Inside the Ebara Works Co., Ltd. (72) Masayuki Kumekawa 11-1, Haneda Asahi-cho, Ota-ku, Tokyo F inside the Ebara Works F Term (reference) 4K024 AA09 BA15 BB11 BC10 CA10 CB11 CB15 GA02

Claims (4)

[Claims] 1. A plating apparatus comprising: a substrate to be plated held by a substrate rotating and holding means; a plating surface in contact with a plating solution in a plating tank; and an anode electrode provided to face the substrate to be plated. 3. The plating apparatus according to claim 1, further comprising means for generating a swirling flow in a plating solution between the substrate to be plated and the anode electrode in a direction opposite to the rotation direction of the substrate to be plated. 2. A plating method in which a substrate to be plated and an anode electrode are opposed to each other via a plating solution, and current is applied between the substrate to be plated and the anode electrode while rotating the substrate to be plated to plate the surface of the substrate to be plated. In the plating method, a swirling flow is generated in the plating solution between the substrate to be plated and the anode electrode in a direction opposite to the rotation direction of the substrate to be plated during the plating. 3. A plating solution supply pipe for supplying a plating solution into a plating tank in a direction eccentric from a center of the plating tank. 2. The plating apparatus according to 1. 4. A means for generating a swirling flow in the plating solution is constituted by a rotating object provided in the plating solution and rotating, or by means for rotating the anode electrode itself. The plating apparatus according to claim 1.