JPH02240222A - Plating apparatus for semiconductor wafer - Google Patents

Abstract

PURPOSE:To deposit uniform plating on a wafer of any size by rotating a wheel having a flow-controlling bladed in the upper inside of a plating vessel. CONSTITUTION:Plating liquid is supplied into a plating vessel 6 as a liquid stream 8 from flowing passage 12 at lower part of the plating vessel 6. The stirring wheel 3 is fitted into a stirring wheel supporting groove 13 near the semiconductor wafer 1, and the wheel 3 is rotated with an inducing wheel 4. When the liquid stream 8 passes through the stirring wheel 3 toward the semiconductor wafer 1, flowing of the liquid is straightened with a liquid straightening blade 3b of the stirring wheel 3. A uniform plating deposit layer is formed to the whole wafer 1 and also bubbles existing just below the wafer 1 at the time of setting the wafer 1 can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a semiconductor wafer plating apparatus that forms electrodes such as wiring electrodes and bumps on the surface of a semiconductor wafer.

[Summary of the invention]

The present invention is particularly featured in a plating apparatus for forming electrodes such as wiring electrodes and bumps on semiconductor wafers by electroplating. A rotating wheel is installed to perform plating while eliminating the directionality of the plating solution flow. Furthermore, the plating apparatus is capable of quickly removing air bubbles generated during plating.

[Conventional technology]

Conventionally, in order to form electrodes such as wiring electrodes and bumps on a semiconductor wafer, a conductive film is generally provided on the wafer, and then areas other than the required areas are masked with a resist film, and electroplating is performed using a jet or dip method. The structure of the jet plating apparatus is as typified by Japanese Patent Application Laid-Open No. 53-19147, in which contact bottles 2 serving as cathode electrodes are appropriately dispersed at the upper end of a plating tank 6 having a cylindrical shape with different levels as shown in FIG. A wafer 1 is placed on the contact bin 2. An anode electrode 7 is provided inside the plating tank 6 facing the wafer l, and a voltage is applied between the cathode electrode and the anode bridge while the plating solution is jetted upward from the bottom of the plating tank 6. The surface of the wafer 1 is plated by passing a plating current. At this time, the plating solution flows as shown by the arrows in FIG. 3, and after plating, it flows out from the gap between the wafer 1 and the upper part of the main body of the plating bath 6 and returns to the plating bath.

[Problem to be solved by the invention]

However, in the plating vt apparatus with the above configuration, when the plating solution is jetted from the bottom to the top of the plating tank, the flow direction of the plating solution is as shown by the arrow in Fig. 3, and the flow of the plating solution is at the center of the jet. Bad part A occurs and bubbles accumulate, making the supply of plating flow to the center of the wafer worse than to other parts. As a result, the metal ion concentration in that area becomes thinner, causing plating abnormalities and variations in plating thickness.

This phenomenon of variation in plating thickness becomes more noticeable as the diameter of the wafer increases, and in the worst case, the plating film thickness at the center of the wafer becomes extremely poor.

In addition, as seen in Japanese Patent Application Laid-open No. 57-51287, as an example of a plating device aimed at preventing the cathode electrode from being plated and preventing deterioration of the plating solution,
An apparatus has been proposed in which a stirring blade is provided in a plating tank to reduce the directionality of patterns that tends to occur when thick plating is performed.

According to this method, the problem of uniformity of the plating film thickness is improved to some extent. However, the main purpose of the above plating apparatus configuration is to prevent the cathode electrode from plating onto the contact bottle and to reduce the amount of air entrained in the plating solution. For this reason, the plating solution passing between the plating solution blow-up tube and the outer tubular body must rise and quickly return to the plating solution tank without being affected by the plating solution. If this is to be achieved, it is not possible to use the previously proposed stirring rotor that has a large stirring power, and
On the other hand, if the stirring power is weak, there is a problem in that variations in plating thickness cannot be improved.

An object of the present invention is to provide a semiconductor wafer plating apparatus that eliminates these drawbacks and allows for high density plating.

[Means to solve the problem]

The present invention is a plating apparatus that solves the above problems, and is capable of uniformly depositing plating on the surface of a semiconductor wafer to be plated.
The purpose is to provide a plating apparatus that is not affected by the size of the wafer, and the structure of the plating apparatus is an additional mechanism to the conventional plating apparatus. It was designed to provide rotational movement around the inner circumference.

[Effect]

When a semiconductor wafer is plated with a plating apparatus having such a mechanism, the flow of the plating solution on the wafer surface is quickly directed to the outside of the wafer by the wheel having the vane shape shown above (hereinafter abbreviated as stirring wheel). In addition, by evenly distributing and directing the plating solution, the directionality of the plating solution flow is eliminated, and at the same time, the air bubbles that have accumulated on the wafer surface are quickly removed, resulting in the entire wafer surface being A uniform stirring state will be obtained. In addition, since the flow of the plating solution by the stirring wheel 3 occurs along the plating surface of the wafer l, it is not affected by the size of the wafer.
Note that this stirring wheel 3 has a gear on its outer periphery, and since rotational movement is performed here, the plating solution does not become a factor that impedes the flow of the plating solution, and the plating solution is rectified only by the rectifying blades 3b.

(Example) The apparatus of the present invention will be explained below based on the drawings.The drawings show an embodiment of the apparatus of the present invention, and FIG. FIG. 2 is a diagram showing an embodiment of the stirring wheel of the present invention.

In the semiconductor wafer plating apparatus according to the present invention, a plurality of cup-shaped plating baths 6, for example, 25 cup-shaped plating baths 6, are arranged at the same height in five columns and five rows, and are attached to a plating bath 10. As shown in FIG. 1, there is a flow path 12 for the plating solution 11 at the bottom of the plating tank 6, and the plating solution is supplied to the plating tank through this flow path 12, resulting in a liquid flow as shown in 8. . The stirring wheel 3 is disposed near the semiconductor wafer l, is fitted into the stirring wheel support groove 13, and has a mechanism in which it is rotated inside the plating tank 6 by a guide wheel 4, and the guide wheel 4 is in communication with a power source. The rotational movement is provided by a shaft 5 that is As shown in FIG. 2, the stirring wheel 3 includes a gear portion 3a that is rotated by an induction wheel 4 and a plating solution rectifying blade portion 3.
It has an integral structure of b. A cathode jig (cathode bin) 2 for fixing a wafer fixes a semiconductor wafer 1 and is connected as a cathode electrode, and an anode electrode 7 is placed below the plating tank 6 and connected to a plating power source. At this time, the plating surface of the semiconductor wafer faces downward.

The plating solution flows into the plating solution flow path 12 by gas pressure such as nitrogen or air, pump pressure feeding, etc., becomes the liquid flow 8 as described above, and heads toward the upper semiconductor wafer through the stirring wheel 3.
However, at this time, due to the rotation of the stirring wheel 3, the flow of the plating solution is biased to the liquid rectifying blade 3 of the stirring wheel 3.
It is rectified by b.

In the plating apparatus configured as described above, when a semiconductor wafer 1 is plated, the plating solution 11 flows out of the plating tank in a smooth liquid flow by the stirring wheel as shown in Fig. 1 and is discharged into the plating bath. Return to 10. This not only makes it possible to form a uniform plating deposit layer over the entire wafer, but also makes it possible to eliminate air bubbles that exist directly under the wafer when setting the semiconductor wafer 1.

The results of a plating precipitation experiment using the plating apparatus shown in the above example are shown in FIG. 4. In this experiment, plating was performed under appropriate plating conditions using a solder plating bath as the plating bath. As a result, when using the device of the present invention, more plating solution is supplied to the center of the wafer than with conventional plating devices.
It has become possible to perform plating treatment with extremely little variation in plating thickness.

It goes without saying that the shape of the blade portion 3b of the stirring wheel 3 may be any other shape, and that the method of driving the stirring wheel 3 may be any other method.

〔Effect of the invention〕

As described above, according to the present invention, after the plating solution is supplied over the entire semiconductor wafer, there is no accumulation of the plating solution, there is no directionality of the solution, and the generated air bubbles are immediately removed, so there is no need to worry about insufficient supply of the plating solution. You can resolve any associated problems.

As a result, it is possible to obtain uniform plating. Furthermore, since the liquid flow due to the rectification effect of the stirring wheel is directed along the surface of the semiconductor wafer, uniform plating can be achieved regardless of the size of the wafer. In addition, since plating bubbles are quickly removed, it is possible to apply a higher current density than conventional current densities, which has the effect of shortening plating time and changing the properties of plating films such as plating low melting point solder plating films. can get.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the plating apparatus of the present invention;
FIG. 2 is a diagram showing an embodiment of the stirring wheel of the present invention, FIG. 3 is a sectional view of a conventional plating apparatus, and FIG. 4 is a diagram showing the results of a plating precipitation experiment. 3... Stirring wheel 4... Guide wheel 5... Shaft 6... Plating tank 7... Anode electrode 8... Plating solution flow 9... Plating solution rectified by rectifier wheel lO.・・・
Plating bath 11... Plating solution 12... Plating solution flow path 13... Stirring wheel support groove A... Parts with poor liquid flow Applicant: Seiko Electronic Industries Co., Ltd. Agent Patent attorney: Keisuke Hayashi 1・te wafer 2... contact pin (cathode electrode) misfire β month r
'), Sectional view #51 showing the 1st 91Σ of Kisou J Sumire Figure 2 Figure 2 showing the contribution of the 30th month of the month of completion of the book Figure 2 of the conventional Mesa device! R-view diagram:! I-Kundedai, Kensuri-kuri and G-Man 4 Figure

Claims (1)

[Claims] In a plating apparatus that forms a metal layer on the exposed portion of the wafer surface by bringing a previously masked semiconductor wafer into contact with the surface of the plating solution, the plating tank has a blade shape inside the upper part of the plating tank and rotates around the inner periphery of the plating tank. A plating device for semiconductor wafers, characterized in that it is equipped with a mechanism having a wheel for plating.