JP3018796B2 - Jet plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet plating apparatus capable of improving the in-plane uniformity of plating applied to a substrate by making the current density at the periphery of a plating solution uniform.

[0002]

2. Description of the Related Art Conventionally, in the semiconductor industry such as LSI and VLSI, projecting connection electrodes called bumps are formed on a large number of elements formed on a silicon wafer (substrate) using a jet plating apparatus. Is done. FIG. 3 is a schematic configuration diagram showing an example of the jet plating apparatus. The jet plating apparatus 1 has a cylindrical plating tank 3 for storing a plating solution 2.
And a fixed plate 4 made of a disc-shaped insulating material, which is horizontally disposed slightly above the plating tank 3, and bumps should be formed on the lower surface 4 a of the fixed plate 4. Silicon wafer 6 coated with resist 5 except for the position
Has been fixed. The plating solution 2 is, for example, lead 95
% -Tin 5%, lead 90% -tin 10%, lead 95% -indium 5%, etc. High lead solder is electrochemically dissolved.

In order to form bumps on a silicon wafer 6 using the jet plating apparatus 1, a lower surface 4a of a fixing plate 4 is required.
The silicon wafer 6 coated with the resist 5 is fixed. Next, the fixing plate 4 is horizontally arranged slightly above the plating solution 2 while the plating solution 2 is jetted, and the silicon wafer 6 fixed to the lower surface 4 a is brought into contact with the liquid surface 2 a of the plating solution 2. In this state, if a predetermined voltage is applied with the plating solution 2 being positive and the silicon wafer 6 being negative, plating of the high lead solder is applied to the positions of the silicon wafer 6 where bumps are to be formed. After a lapse of a predetermined time, the silicon wafer 6 is separated from the liquid level 2a.
Is removed from the fixing plate 4, and the applied resist 5 is removed. In this way, a silicon wafer 6 having bumps formed at predetermined positions of each element can be obtained.

[0004]

By the way, in the jet plating apparatus 1 described above, since the turbulent flow is apt to occur in the peripheral portion 2a of the plating solution 2, the current density of the peripheral portion 2a tends to fluctuate. There is a problem in that the height and diameter of the bumps at the peripheral edge of No. 6 vary. Therefore, in the element at the peripheral portion, the yield is remarkably reduced, which is one of the causes for increasing the manufacturing cost. In recent years, the diameter of the silicon wafer 6 is becoming larger and larger, and variations in the heights and diameters of the bumps at the peripheral edge of the silicon wafer 6 are a great obstacle to reducing the cost of the device. It was necessary to greatly reduce the variation in the height and diameter of the bumps.

The present invention has been made in view of the above circumstances, and has an object to make the current density at the peripheral portion of a substrate uniform.
The turbulence at the periphery of the substrate can be suppressed by the
Jet to improve the in-plane uniformity of the plating applied to the surface
An object is to provide a plating apparatus.

[0006]

In order to solve the above-mentioned problems, the present invention employs the following jet plating apparatus. That is, a plating tank for storing a plating solution, and a fixing plate disposed above the plating tank and having a substrate fixed to the lower surface,
While flooding the plating solution from the top of the plating vessel with electric current between the plating tank and the substrate, the jet plating apparatus plating the predetermined portion of the substrate, are arranged on the substrate in the outer peripheral portion of the substrate An electrode having the same polarity as the substrate is provided.

[0007]

In the jet plating apparatus of the present invention, an electric current is applied between the plating tank and the substrate and the electrode, and the plating solution overflows from the upper part of the plating tank. In this case, since the substrate and the same polarity of the electrodes is provided on the outer peripheral portion of the substrate, menu
Turbulence is likely to occur in the area of the electrode corresponding to the periphery of the liquid
However, turbulence is unlikely to occur in the area of the substrate,
Substantially uniform current density fluctuations are suppressed even at the periphery of the substrate
The current is a uniform flow. Accordingly
The plating applied to a given part of the substrate is extremely uniform
It becomes small with rich variation, and the yield of plating
Is significantly improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A jet plating apparatus according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a jet plating apparatus 11.
FIG. 2 is a perspective view of the fixing plate 12. The jet plating apparatus 11 includes an annular electrode 12 on an outer peripheral portion of the silicon wafer 6 fixed to the lower surface 4a of the conventional fixing plate 4.
In the figure, the same components as those of the conventional jet plating apparatus 1 are denoted by the same reference numerals, and description thereof will be omitted. Here, the plating solution 2 side is positive and the silicon wafer 6
The voltage values of the voltage between the plating solution 2 and the silicon wafer 6 and between the plating solution 2 and the electrode 12 are independently controlled by a control device (not shown) so that the electrode 12 side becomes negative.

In order to form bumps on the silicon wafer 6 using the jet plating apparatus 11, the silicon wafer 6 coated with the resist 5 is fixed at a predetermined position on the lower surface 4a surrounded by the electrodes 12. Next, while the plating solution 2 overflows from the upper part of the plating bath 3, the fixing plate 4 is horizontally arranged slightly above the plating solution 2, and the silicon wafer 6 and the electrodes 12 fixed to the lower surface 4a are separated from the plating solution 2. Contact the surface 2a. In this state, if a predetermined voltage is applied with the plating solution 2 being positive and the silicon wafer 6 and the electrode 12 being negative, plating is performed on the silicon wafer 6 at positions where bumps are to be formed.

In this case, since the negative polarity electrode 12 having the same polarity as that of the silicon wafer 6 is provided on the outer peripheral portion of the silicon wafer 6, a uniform current flows from the plating solution 2 toward the silicon wafer 6. Thus, the fluctuation of the current density in the peripheral portion of the silicon wafer 6 is eliminated.
Therefore, the plating applied to the silicon wafer 6 is extremely uniform and has a small variation.
The yield of devices on the silicon wafer 6 is significantly improved. After a lapse of a predetermined time, the silicon wafer 6 is moved to the liquid level 2a.
Then, the silicon wafer 6 is removed from the fixing plate 4 and the applied resist 5 is removed. In this way, it is possible to obtain a silicon wafer 6 in which the in-plane uniformity of plating is improved, the variation in bump height and diameter is small, and the element yield is improved.

Also, a 4-inch silicon wafer prepared using the jet plating apparatus 11 of the above embodiment (Example)
When the yield of each semiconductor element of a 4-inch silicon wafer (conventional example) prepared by using the conventional jet plating apparatus 1 was compared with that of the conventional example, the yield was 100% in the example and 75% in the conventional example. there were. From this, it was confirmed that the yield of the semiconductor elements of the silicon wafer of the above example was significantly improved as compared with the conventional example.

As described above, according to the jet plating apparatus 11 of this embodiment, the position of the outer periphery of the silicon wafer 6 fixed to the lower surface 4a of the fixing plate 4 is set to the same polarity as that of the silicon wafer 6. Since the annular electrode 12 is provided, the current flowing from the plating solution 2 toward the silicon wafer 6 can be made uniform, and the fluctuation of the current density at the peripheral portion of the silicon wafer 6 can be extremely reduced. . Therefore, the in-plane uniformity of the plating applied to the silicon wafer 6 can be improved and the variation can be reduced, and the yield of elements on the silicon wafer 6 can be significantly improved.

[0013]

As described above, according to the jet plating apparatus of the present invention , the substrate is arranged on the outer peripheral portion of the substrate.
Since the electrodes having the same polarity as those described above are provided, the flow of current from the plating solution to the substrate can be made uniform, and the fluctuation of the current density at the peripheral portion of the substrate can be extremely reduced. Therefore, the in-plane uniformity of the plating applied to the substrate can be improved and the variation can be reduced, and the yield of elements and the like by the substrate can be significantly improved.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a fixing plate according to one embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a conventional jet plating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Jet plating apparatus 12 Electrode 2 Plating solution 3 Plating tank 4 Fixing plate 4a Lower surface 5 Resist 6 Silicon wafer (substrate)

Claims (1)

(57) [Claims] 1. A plating tank for storing a plating solution, and a fixing plate disposed above the plating tank and having a substrate fixed to a lower surface thereof, wherein a current flows between the plating tank and the substrate, and a plating solution is provided. In a jet plating apparatus in which a predetermined portion of the substrate is plated while overflowing from the upper part of the plating tank, an electrode having the same polarity as the substrate is provided side by side on the substrate at an outer peripheral portion of the substrate. Jet plating equipment.