JP2002060996A - Plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the fine air bubbles, such as air, in a plating solution which obstructs the formation of fine patterns even in electroplating of copper wiring, etc., in view of the recent progress in the higher-scale integration of semiconductor elements. SOLUTION: This device has means of circulating an aqueous copper sulfate solution to be used as a plating liquid, capturing the air bubbles, such as air, in the aqueous copper sulfate solution with a plate material, such as a porous alumina plate, and discharging and removing the air bubbles captured by the plate materials by a drain, etc., when the copper wiring is embedded and formed by plating on the semiconductor elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus used for electrolytic plating of copper embedded by a damascene method or the like.

2. Description of the Related Art In recent semiconductor devices, development of fine processing technology is urgently required due to high integration, and even in electrolytic plating of copper wiring and the like, fine bubbles such as air in a plating solution which inhibit formation of a fine pattern are new. A removal method is needed.

[0003]

2. Description of the Related Art FIG. 4 is an explanatory view of a conventional example.

In the figure, 2 is a bubble, 3 is a plating solution, 1
0 is a silicon oxide film, 11 is a barrier metal, 12 is plated copper, 13 is a plate, 14 is a hole, 15 is a wafer, 1
6 is poor plating.

[0005] In a conventional manufacturing apparatus of the electrolytic plating method, in order to improve the uniformity of the plating film thickness, FIG.
0.4 mm is applied to a polypropylene resin plate as shown in FIG.
A plate 13 having 146 holes with 83 mm holes was used.

However, as shown in FIG. 4B, fine bubbles 2 of about 10 μm to 50 μm such as air contained in the aqueous solution of copper sulfate used as the plating solution 3 pass through the holes 14 of the plate 13. As a result, air bubbles 2 such as air adhere to a plate to be plated such as a wafer 15 during the formation of copper wiring, and as shown in an enlarged view in FIG. The copper plating is not performed on the portion, and plating failure 16 of the embedded copper wiring occurs.

[0007]

Therefore, in the conventional method, air bubbles or the like cannot be trapped, copper plating is not applied to a portion where the air bubbles are attached, and plating failure such as disconnection of copper wiring is caused. Problem had arisen.

[0008] In view of the above, the present invention is provided for the purpose of removing bubbles such as air contained in a plating solution composed of a copper sulfate aqueous solution or the like.

[0009]

FIG. 1 is an explanatory view of an apparatus according to the present invention.

In the figure, 1 is a porous plate material, 2 is a bubble,
Reference numeral 3 denotes a plating solution, 4 denotes a cathode, 5 denotes an anode, 6 denotes a power source, 7 denotes a plating tank, 8 denotes a circulating unit, and 9 denotes a bubble discharging unit.

As shown in FIG. 1, the apparatus of the present invention is an electrolytic plating apparatus for embedding copper wiring on a semiconductor wafer by a damascene method, comprising a circulating means for circulating and supplying a plating solution into a plating tank. Providing a porous plate material in the middle of the circulating means, capturing means for capturing bubbles contained in the plating solution using the porous plate material, and discharging means for discharging and removing the captured bubbles. I have.

That is, in a plating apparatus for performing electrolytic plating for copper wiring, a plating solution 3 is continuously overflowed from a plating tank 7 by a circulation means 8 such as a pump to circulate a plating solution 3 in a plating apparatus for performing electrolytic plating for copper wiring. The fine bubbles 2 contained in the plating solution 3 are captured by the porous plate 1 made of the porous alumina plate or the like of the present invention.

According to this method, bubbles 2 such as fine air do not adhere to the plating portion on the wafer serving as the anode 5, and plating defects caused by the bubbles 2 can be reduced.

The bubbles 2 trapped in the porous plate 1 are discharged and removed from the plating apparatus by a bubble discharging means 9 such as a drain.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a plating apparatus according to the present invention, FIG. 2 is an explanatory view of an embodiment of the present invention, and FIG. 3 shows the aperture ratio of a plate and the number of plating defects.

In the figure, 1 is a porous plate material, 2 is a bubble,
3 is a plating solution, 4 is a cathode, 5 is an anode, 6 is a power supply, 7 is a plating tank, 8 is a circulation means, 9 is a bubble discharge means,
13 is a plate.

The damascene method was used for plating for the embedded wiring of copper. A description will be given with reference to the explanatory view of the plating apparatus of the present invention in FIG. 1 and the schematic sectional view in the order of steps shown in the explanatory view of one embodiment of the present invention in FIG.

As shown in FIG. 2A, a hole for embedding copper wiring having a diameter and width of 0.25 μm and a depth of 1 μm is formed in a silicon oxide film 10 formed on a wafer of a plate to be plated. The barrier metal 11 is formed thin so as to cover the groove and the groove.

Next, using the plating apparatus shown in FIG.
In the embodiment, the air contained in the plating solution 3 made of an aqueous solution of copper sulfate is used by using a porous alumina plate, which is a porous plate material 1 having a diameter of 200 mmΦ and quenched at 1050 ° C. provided in the middle of circulation of the overflowing plating solution 3. Is removed. This porous alumina plate has a purity of 9
9%, a thickness of 3.1 mm, a hole diameter of 10 μmΦ, and a porosity of 35% were used.

Thereafter, a plating voltage of 12 V and a plating current of 4
At 0 mA, as shown in FIG. 2B, plated copper is plated over the entire surface of the wafer to a thickness of 1.5 μm by electrolytic plating on the wafer. At that time, a porous alumina plate having a thickness of 3.1 mm, a hole diameter of 10 μmΦ, a porosity of 99%, and a porosity of 35% was used.

The plate 13 made of polypropylene was used as it was as a conventional rectifying plate for the plating solution 3 to reach the wafer evenly and to make the plating thickness and the like uniform.

As described above, in the electrolytic plating of copper, bubbles 2 such as air contained in the aqueous solution of copper sulfate of the plating solution 3 are always trapped by the porous alumina plate having fine pores, and the plating solution from which the bubbles 2 are removed. 3 After the completion of copper plating,
It overflows from the plating tank 7 and is sent again to the plating tank 7 through a circulating means 8 such as a circulation pump, and the generated fine bubbles 2 such as air are again captured by the porous alumina plate.

Here, bubbles such as air trapped on the porous alumina plate, which is the porous plate material 1, instantaneously move the drain cock, which is the bubble discharging means 9, after the copper plating for each wafer is completed. Open a small amount of plating solution 3
At the same time, it is discharged and removed outside the plating tank 7.

In this embodiment, a drain is used as the means for discharging and removing the air bubbles 2. However, other means for discharging and removing the air by means of a mini-dropper may be used.

The material of the porous plate member 1 for removing the bubbles 2 may be ceramic other than alumina, or a filter paper (including a millipore filter) made of plastic (including nylon) depending on the plating solution.

Subsequently, as shown in FIG. 2C, the plated copper 12 deposited on the wafer is polished from the surface by a CMP apparatus to remove the plated copper 12 on the wafer surface, and the holes in the silicon oxide film 10 are removed. And leave the plated copper 12 in the groove,
Embedded copper wiring.

As a result, as shown in FIG. 3, in the conventional plate 13 made of polypropylene resin, about 10 plating defects occurred per wafer, whereas the plating purity of the alumina of the embodiment of the present invention was 92%. %, The plating using a porous alumina plate having a porosity of 45% has one plating defect, and the purity of the porous alumina plate is 99%.
In the plating using the porosity of 35%, a favorable result of zero plating failure could be obtained.

[0028]

As described above, according to the present invention,
Bubbles such as air contained in the circulated plating solution can be captured by the porous alumina plate, and the defective rate caused by the bubbles can be reduced, which can contribute to the improvement of the quality of the semiconductor device.

Further, depending on the temperature at the time of forming the porous alumina plate, plates having different porosity can be formed, and a filter effect can be expected.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a plating apparatus of the present invention.

FIG. 2 is an explanatory diagram of one embodiment of the present invention.

Fig. 3 Plate opening ratio and number of plating defects

FIG. 4 is an explanatory view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous board material 2 Bubbles 3 Plating solution 4 Cathode 5 Anode 6 Power supply 7 Plating tank 8 Circulation means 9 Bubble discharge means 10 Silicon oxide film 11 Barrier metal 12 Plated copper 13 Plate 14 Hole 15 Wafer 16 Plating failure

Claims (1)

[Claims] 1. A circulating means for circulating and supplying a plating solution into a plating tank, and a porous plate material provided on an intermediate route of the circulating means, and air bubbles contained in the plating solution are captured using the porous plate material. A plating apparatus comprising: a capturing unit; and a discharging unit configured to discharge and remove the captured air bubbles.