JP2641594B2 - Plating equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a plating used for metallizing a semiconductor wafer process.

[Conventional technology]

FIG. 3 is a schematic view showing a conventional plating apparatus and its tank, in which 1 is a tank for storing the plating solution, 2 is a heater for keeping the temperature of the plating solution constant,
3 is a pump for circulating the plating solution, 4 is a filter for removing particles in the plating solution, 5 is a plating cup for jetting the plating solution into the inside, and 6 is a current supply to the object to be plated. 7 is an anode, 8 is a semiconductor wafer to be plated, and 9 is an anode.
Denotes a plating solution, and 10 denotes an overflow tank.

FIG. 3 shows a case where there is one plating cup, but there are many cases where there are actually a plurality of plating cups.

 Next, the operation will be described.

When plating using this apparatus, the heater 2
While maintaining the temperature of the plating solution at 50 to 100 ° C. by the pump 3, the plating solution is circulated through each cup by the pump 6 and the anode 7
Plating is performed on the semiconductor wafer by supplying a current therebetween.

At this time, for example, a waveform as shown in FIG. 4 is used. FIG. 4 (a) is a DC method, FIG. 4 (b) is a pulse method,
FIG. 3C shows a PR (periodical reverse) method.

[Problems to be solved by the invention]

By the way, since the plating solution is an electrolyte, it has a property of easily conducting electricity. In FIG. 3, when plating is performed simultaneously using a plurality of plating cups, the plating solution circulates between the cups and returns to the same tank, so that a current path is generated through the plating solution. Therefore, unintended plating is formed, and this is a major cause of uneven plating and abnormal plating.

The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide a plating apparatus which is unlikely to cause variations in plating thickness and abnormal plating, and is capable of precision plating for forming fine wiring. .

[Means for solving the problem]

The plating apparatus according to the present invention includes an introduction pipe for introducing a plating solution, a cathode and an anode for supplying a current to an object to be plated immersed in the plating solution introduced by the introduction pipe, and a discharge pipe for discharging the plating solution. A plurality of plating tanks having
A plurality of child tanks formed inside the tank by a partition plate having a sequentially lower height, and a reflux means for refluxing the plating solution from the downstream side of the child tank toward the most upstream child tank when plating is interrupted, A plating solution tank that allows a stepwise flow of the plating solution when the plating solution overflows the partition plate, a sub-tank of the plating solution tank, and the introduction pipe and the discharge pipe of the plating tank corresponding to the sub-tank. And a circulating means for circulating a plating solution through the piping during plating.

[Action]

In the present invention, with the configuration described above, since each of the daughter tanks in the plating solution tank is partitioned by the partition plate, no current component flows through the plating solution. When plating is interrupted, the plating solution refluxes from the downstream side of the child tank toward the most upstream child tank, and the plating solution flows in the child tank in a stepwise manner, so that the composition of the plating solution is uniformly maintained between the child tanks. Dripping. Further, the plating solution tank and the corresponding plating tank are connected by piping, respectively, and the plating solution is circulated through the piping during plating, so that the composition of the plating solution in each child tank is Is kept uniform.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a tank of a plating apparatus according to an embodiment of the present invention. In FIG. 1 (a), reference numeral 1 denotes a tank, and 13 denotes a first partition plate provided in the tank. It is formed as follows. Reference numeral 2 denotes a heater provided inside each of the child tanks separated by the first partition plate, and has a function of keeping the temperature of the plating solution constant. Reference numeral 14 denotes a second partition plate provided inside each of the child tanks separated by the first partition plate, and has a function of temporarily guiding the plating solution overflowing from the next to the lower portion. Reference numeral 15 denotes a third partition plate provided inside each child tank divided by the first partition plate, and has a function of uniformly flowing a plating solution overflowing from the next to the upper portion from the lower portion. Numerals 11a and 12a are valves, and 3a is a pump. When plating is interrupted, the plating liquid is returned from the downstream side of the child tank to the most upstream child tank and circulates the plating liquid between the child tanks. 4a is a filter. A pump 3 has a function of circulating the plating solution between the cups. 11 and 12
Is a valve and 4 is a filter. 16 and 17 are an inlet pipe and an outlet pipe of the plating cup, respectively. The plating apparatus as a whole has a configuration as shown in FIG. The pipes 16 and 17 in FIG. 1A are connected to the pipes 16 and 17 of the plating cup (plating tank) 5 shown in FIG. 2B, respectively.

 Next, the operation of this embodiment will be described.

The heater 2 circulates the plating solution in each cup while maintaining the temperature of the plating solution at 50 to 100 ° C., and supplies a current between the cathode and the anode to perform plating on the semiconductor wafer. At this time, for example, a waveform as shown in FIG. 4 is used. 4 (a) shows the DC method, FIG. 4 (b) shows the pulse method, and FIG. 4 (c) shows the PR (periodical reverse) method.

Here, the plating solution is shut off by valves 11a and 12a and further circulated to the cup side, so that the corresponding liquid level in the tank is only the volume of each pipe and cup as shown in FIG. 1 (b). descend. Therefore, no current component flows through the plating solution between the sub-tanks separated by the first partition plate.

When plating is not to be performed, the valves 11a and 12a are opened and the pump is opened in order to equalize the plating solution composition in each child tank.
Circulate between each child tank according to 3a. At this time, the plating solution is sucked from the valve 11a side by the pump 3a and sent out to the valve 12a side, and then overflows from the first partition plate 13 and flows out to an adjacent tank. Then, it flows to the lower part by the second partition plate 14 and flows out to the upper part by the third partition plate 15. In this way, the composition of the plating solution is made uniform by flowing stepwise into the adjacent child tank in order.

Although the above embodiment has been described in connection with plating, the present invention is also applicable to the case of etching, and has the same effect as the above embodiment.

[Effects of the Invention] As described above, according to the plating apparatus of the present invention,
A plurality of plating tanks having an introduction pipe for introducing a plating solution, a cathode and an anode for supplying a current to an object to be plated immersed in the plating solution introduced by the introduction pipe, and a discharge pipe for discharging the plating solution, A plurality of child tanks formed inside the tank by a partition plate having a reduced height, and a reflux means for refluxing the plating solution from the downstream side of this child tank toward the most upstream child tank when plating is interrupted, A plating solution tank that allows a stepwise flow of the plating solution when the solution overflows the partition plate, a sub tank of the plating solution tank, and the introduction pipe and the discharge pipe of the plating tank corresponding to the sub tank. Each of the pipes has a connecting pipe, and a circulating means for circulating the plating liquid through the pipe at the time of plating is provided, so that a current component flowing through the plating liquid is generated. Not. Accordingly, variations in plating thickness and occurrence of abnormal plating are significantly reduced. Further, since the composition of the plating solution is kept uniform, there is an effect that a product having good maintainability can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a tank of a plating apparatus according to one embodiment of the present invention, and FIG. 1 (a) is a view showing a state where a plating solution is circulating in the tank. FIG. 1 (b) is a view showing a state in which plating is formed by circulating on the plating cup side, and FIG. 2 is a view showing a plating apparatus including the tank of the embodiment of FIG. 2A is an overall view thereof, and FIG. 2B is a sectional view of a plating cup portion. FIG. 3 is an overall view of a conventional plating apparatus. FIG. 4 is a diagram showing a waveform of a current supplied to the plating cup, and FIG.
FIG. 4 (b) shows the pulse method, and FIG. 4 (c) shows the PR (peri
It is a figure which shows an odical reverse) method. In the figure, 1 is a tank, 2 is a heater, 3 and 3a are pumps, 4 and 4a are filters, 5 is a plating cup, 6 is a cathode, 7 is an anode, 8 is a semiconductor wafer, 9 is a plating solution, and 10 is an overflow tank. , 11 and 11a are outlet valves, 12
And 12a are valves, 13 is a first partition plate, 14 is a second partition plate, 15 is a third partition plate, 16 is a cup inlet pipe, and 17 is a cup outlet pipe. In the drawings, the same reference numerals indicate the same or corresponding parts.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C25D 21/10 301 C25D 21/10 301

Claims (1)

(57) [Claims] 1. A plurality of pipes having an inlet pipe for introducing a plating solution, a cathode and an anode for supplying a current to an object to be plated immersed in the plating solution introduced by the inlet pipe, and a discharge pipe for discharging the plating solution. A plating tank, a plurality of child tanks formed inside the tank by a partition plate having a sequentially decreasing height, and a reflux means for refluxing the plating solution from the downstream side of the child tank toward the most upstream child tank when plating is interrupted. A plating solution tank that allows a stepwise flow of the plating solution when the plating solution overflows the partition plate, a sub tank of the plating solution tank, and the introduction pipe of a plating tank corresponding to the sub tank. And a discharge pipe, and a circulating means for circulating a plating solution through the pipe when forming the plating.