JPS5866333A - Washing tank - Google Patents

Abstract

PURPOSE:To efficiently wash by a method wherein opening areas are changed in accordance with the surface length in the flowing direction of a washing solution for a washed substance and holes are provided on a plate controlling the flow of washing solution. CONSTITUTION:For example, 3mm.phi holes 61 and 4mm.phi holes 62 are provided on the area xXy of a baseplate 41 conforming to the region existing a discoid Si substrate 1. The distance of the surface in parallel with the flowing direction of wash water is long at the center Z1 and short at the periphery Z2. The maximum holes 62 are provided just under Z1. Holes 63 are 2.5mm.phi holes for introducing solution. This constitution increases flowing amount at the central section of the substrate 1 and permits efficient and rational washing. When a water current is sufficiently strong, the appreciable volume of water is obtained by providing a small hole meeting a feedwater port 5 at the center 64 of the baseplate 41. The same effect is obtained by providing holes having the same opening area with high density at the vicinity of the region 65 just under the Z1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a cleaning tank used for cleaning objects, particularly for cleaning semiconductor wafers.

Washing and cleaning of semiconductor wafers is one of the important steps in the manufacturing process of semiconductor devices. It is desirable to use highly purified water that has been specially treated for washing, and to perform washing efficiently with a small amount of water from a cost standpoint. The present invention provides a cleaning tank having a structure that meets this purpose.

An example of a conventional cleaning tank will be explained using cross-sectional views shown in FIGS. 1(-) and 1(b). A large number of disk-shaped semiconductor wafers 1 are set side by side on a jig 2 and placed in a cleaning tank 3. The water that enters from the water supply port 6 flows through many introduction holes 6 drilled in the bottom plate 4.
The water is supplied to the cleaning tank 3 through.

As shown in the plan view of FIG. 1(C), the introduction holes 6 are holes of the same size that are bored in the bottom plate 4 at equal intervals.

A disadvantage of a cleaning tank with such a bottom plate is that water is introduced into all areas, regardless of whether there are semiconductor wafers to be cleaned or not. For this reason, water is also sent to unnecessary areas, such as the area where the semiconductor wafer is present, XX7 in FIG. 1, which has the disadvantage that the cleaning efficiency is not necessarily high.

The present invention eliminates the above-mentioned drawbacks and improves the structure of the bottom plate so that more water can be supplied to the required areas.

An embodiment according to the present invention is shown in FIG. A hole 62 with a large opening area (for example, 3
), and a larger hole 61 (for example, 4 mφ) is installed on the right. As shown in FIG. 1 (-), the distance between the surfaces of the semiconductor wafer to be cleaned that are parallel to the flow direction of the cleaning water is:
It is large 211 at the center of the semiconductor wafer and small z2 at the periphery. Correspondingly, therefore, the largest hole 81 in FIG. 2 is provided directly below Zl. 63
is a cleaning liquid introduction hole of 2.6 mφ. By doing so, the amount of water flowing in the center of the wafer increases, allowing efficient and rational cleaning. Further, a small hole was provided in the center portion 64 of the bottom plate 41. This corresponds to the position of the water supply port 5, and is because if the water flow is strong enough, a small amount of water can be obtained even with a small hole.

The bottom plate shown in the embodiment of FIG. 3 is located within the range xxy corresponding to the area of the semiconductor wafer, and the same opening area is introduced at high density in the vicinity (xlxy) 65 of the location directly below the above-mentioned zl. This is a bottom plate 42 provided with holes. Even if the opening area of each hole is the same, the same effect as the example shown in FIG. 2 can be achieved with respect to the effective opening area, regardless of the density.

As explained above, with the cleaning tank of the present invention, even if the amount of water is the same, a larger amount of cleaning water can be applied to the required area depending on the length of the surface of the semiconductor wafer to be cleaned. This has the advantage that cleaning can be carried out efficiently. In the above embodiment, a semiconductor wafer was used as an example of the object to be cleaned, but it is needless to say that the object is not limited to this example.

[Brief explanation of drawings]

Figures 1 (-) and (b) are cross-sectional views for explaining the cleaning tank, Figure 1 (C) is a plan view of the bottom plate of the conventional example, and Figures 2 and 3 are of the embodiment of the present invention. FIG. 3 is a plan view of the bottom plate. 1... Semiconductor wafer to be cleaned, 3...
・Cleaning tank, 41, 42... Bottom plate, 61, 62.
63...Cleaning liquid introduction hole. Name of agent: Patent attorney Toshio Nakao and one other person
4 2nd t! 1 Figure 3 F

Claims (1)

[Claims] (1) A control plate for controlling the inflow of the cleaning liquid is provided at the inlet of the cleaning liquid, and the control plate has openings corresponding to the length of the surface of the object to be cleaned along the flow direction of the cleaning liquid. A cleaning tank characterized by a hole in which a cleaning liquid introduction hole whose area varies in size is provided. @) The cleaning tank according to claim 1, wherein the opening area is determined by the diameter of the cleaning liquid introduction hole. 0) The size of the opening area increases the drilling density of cleaning liquid introduction holes, J
. The cleaning tank according to claim 1, characterized in that: