JP3103542U - Plating solution stirrer - Google Patents

Abstract

An object of the present invention is to provide an apparatus for controlling a flow of a plating solution in a plating apparatus for forming bumps and fine patterns on a wafer by electrolytic plating, thereby enabling a uniform plating film thickness distribution.
It is possible to remove bubbles adhering to the wafer surface by bubbles generated by ejecting nitrogen gas into the plating solution.
[Constitution] A plating solution flowing from a plating solution inlet disposed on a bottom surface of a plating tank flows along a surface of a wafer mounted on a wafer mounting cassette and flows out from a slit formed in an upper portion of the cassette. The plating solution that has flowed out is sucked into the pump, pressurized by the pump, passed through the filter, and sent again from the plating solution outlet to repeat the above-described circulation.
High-quality plating can be performed by constantly refreshing the plating solution on the wafer surface by this circulation.
Also, small bubbles attached to the wafer surface are captured and removed by large bubbles generated by discharging nitrogen gas from a nitrogen gas outlet disposed on the bottom surface of the plating tank.

[Selection diagram] Figure 1

Description

The present invention relates to an apparatus for agitating a plating solution in an apparatus for electroplating a wafer.

In order to perform electrolytic plating, it is necessary to constantly supply a sufficiently stirred plating solution to a surface to be plated in order to perform high-quality plating. When plating a planar object such as a wafer, it is necessary to expose the wafer surface to a uniform flow of a plating solution, but the conventional stirring method has not sufficiently achieved its purpose.
If minute bubbles adhere to the wafer surface, a large amount of equipment is required for removing the bubbles.

The present invention provides a uniform plating solution flow on a wafer surface at a low cost with a simple apparatus.
Further, it is difficult to remove minute bubbles attached to the wafer surface by a conventional method such as stirring of a plating solution.

According to the present invention, a wafer mounting cassette (4) for mounting a wafer provided with a plating solution inlet (2) and a slit (5) serving as a plating solution outlet disposed in a lower portion of a plating tank (1), a slit ( 5) A plating liquid recovery port (6) which is provided for collecting the liquid flowing out from the pump, and a pump which sends the plating liquid again to the inflow port (2) through the filter (8) for circulation of the recovered plating liquid ( 7) and a nitrogen gas outlet (9) arranged at the lower part of the plating tank for removing fine bubbles.

The plating solution circulation means in the plating bath of the present invention makes it possible to improve the plating film thickness distribution and to perform plating with less voids and plating defects due to bubbles.

In order to make the flow of the plating solution of the present invention uniform on the wafer surface, a plating solution inlet (2) consisting of small holes arranged in a line arranged in the lower part of the plating bath (1) is introduced into the plating bath (1). The flowing plating solution flows out of a slit (5) provided in the wafer mounting cassette (4). The slit (5) is installed so as to oppose the inlet (2), and the plating solution flowing into the plating tank (1) from the inlet (2) becomes a band-like flow to provide a uniform plating solution flow on the wafer surface. .
The plating solution flowing out of the slit (5) is sucked from a plating solution recovery port provided in the plating tank (1) by a pump (7), pressurized by a pump (7), sent to a plating solution outlet (2), and plated. The circulation of the liquid is repeated.
Further, the nitrogen gas jetted from the nitrogen gas jet port (9) installed in the lower part of the plating tank (1) becomes a large bubble and easily floats, floats while being in contact with the wafer surface, and adheres to the wafer surface at this time. Capture and remove foam. At this time, the nitrogen gas fills the space of the plating tank (1) and also has a nitrogen purging function for protecting the plating solution from deterioration and plating.

In the plating tank (1) of the present invention of FIG. 1, a plating solution inlet (2), a wafer mounting cassette (4), a slit (5), a plating solution recovery port (6), a pump (7), and a filter ( 8) By providing a plating solution circulation path arranged as shown in FIG. 1, a uniform plating solution flow can be provided on the surface of the wafer (3) mounted on the wafer mounting cassette (4). A good plating thickness distribution can be obtained. Also, bubbles generated by intermittently ejecting nitrogen gas from the nitrogen gas ejection port (9) before and after plating start capture small bubbles attached to the wafer (3) and remove them. This nitrogen gas also has a function of purging nitrogen gas.

High integration of semiconductor packages. Along with miniaturization, a demand for an apparatus for forming a bump serving as a connection point of an integrated circuit formed on a wafer is increasing. Therefore, the present invention, which is effective in forming bumps by the electrolytic plating method, such as the quality of bumps formed, for example, the uniformity of height and the reduction of defects, has great industrial value.

FIG. 3 is an explanatory view of the plating tank of the present invention.

Explanation of reference numerals

(1) Plating tank (2) Plating solution inlet (3) Wafer
(4) Wafer loading cassette (5) Slit (6) Plating solution recovery port (7) Pump (8) Filter (9) Nitrogen gas jet (10) Anode

Claims (2)

In a dipping type plating apparatus in which wafers are arranged vertically, a plating solution inlet (2) consisting of small holes arranged in a line arranged in the lower part of a plating tank (1) and a detachable partition plate for dividing the tank into two parts are provided. A wafer mounting cassette (4) on which a wafer (3) can be installed is provided on the side of the plating solution inlet (2) on the partition plate surface, and the cassette is parallel to the inlet (2) above the cassette. The plating solution overflows from the slit (5).
The overflowed plating solution flows into the plating tank (1) on the opposite side of the wafer mounting cassette (4) on which the wafer is mounted. The flowing plating solution is sucked by a pump (7) from a plating solution recovery port (6) provided on the bottom surface of the plating tank (1). The sucked plating solution is pressurized by the pump (7) and sent to the inlet (2) again through the filter (8). A vertical wafer plating apparatus in which the flow rate of the plating solution is uniformly applied to the wafer surface by the circulation of the plating solution. In the plating tank of the vertical plating apparatus according to claim 1, the wafer mounting cassette (4), which divides the tank into two parts, is arranged in a lower part on the side of the plating solution inlet (2) side in parallel with the plating solution inlet (2). A nitrogen gas outlet (9) consisting of a small hole arranged in the nozzle is provided, and nitrogen gas is spouted from the outlet (9) as appropriate to generate bubbles, and the bubbles capture and remove small bubbles attached to the wafer. Vertical wafer plating equipment.