JPS6242373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a cleaning tank. In particular, it relates to washing tanks used when washing semiconductor wafers.

A conventional example will be explained with reference to the sectional views shown in FIGS. 1a and 1b. Semiconductor wafers 1 are arranged at equal intervals and set in a jig 2 for cleaning or other processing, and are immersed in water 4 in a cleaning tank 3. This example is a cleaning tank in which two jigs are placed side by side and semiconductor wafers are placed on each of these jigs and cleaned. Water is supplied from the water supply port 5, and as shown in the plan view in Fig. 1c, a large number of holes 7 of the same size are bored at equal intervals in a control plate 6 for controlling the flow rate arranged on the side of the water supply port 5 ( However, the wafer passes through the passage area (a portion of which is omitted in the figure), enters the cleaning tank 3, cleans the wafer, and overflows from the wall of the cleaning tank and is discarded. Alternatively, for the water system, a cleaning method may be adopted in which the operation of supplying water from the water supply port 5 until it once overflows, stopping the water supply, and draining water from the water supply port 5 is repeated.

The disadvantage of the conventional washing tank is that water is supplied almost in the same way from the hole 71 corresponding to the area where the wafer 1 to be cleaned does not exist, and the water in this area hardly contributes to cleaning the wafer. The cleaning efficiency is not good because there is no cleaning agent. From the viewpoint of cleaning efficiency, it is desirable to allow more water to flow over the surface of the wafer 1 even if the same amount of water is used. We want more water to flow in from the bottom plate directly below the x ₁ x y, x ₂ x y positions where the wafer is set.

The second drawback is that a lot of water passes through the holes 72 that are close to the water supply port 5, but only a small amount of water passes through the holes 73 that are far away, resulting in uneven water flow and uneven cleaning efficiency depending on the location. It is what happens.

In order to solve these drawbacks, the present invention provides a range of x ₁ × y and x directly below the wafer position, as shown in the plan view of FIG. ₂ ×y, a large hole, for example, a hole 74 of about 6 mmφ, is provided as a communication port, and the largest hole, for example, a hole 75 of about 8 mmφ, is provided at a position far from the water supply port 5, and a hole 75 of about 8 mmφ is provided at a position where no wafer is present. A small hole, for example, a hole 76 with a diameter of about 5 mm, is provided in the corresponding portion of the control 6. As a result, more water flows almost uniformly on the wafer surface, and in the peripheral area where there is no wafer, that is, in the frame of the jig 2, which corresponds to the size required as a margin for inserting and removing the jig. By flowing water to an extent that does not stagnate, there is an advantage that cleaning can be performed efficiently even if the same amount of water is consumed.

In Figure 3 (part of the right half is omitted), the opening areas of the holes that serve as the flow ports are all the same, x ₁ × y, and x ₂ ×
By increasing the density in the area 77 within y and further increasing the density especially in the area 78 far from the water supply port 5,
This is an example with the same effect as above.

Another embodiment in which there is only one cleaning jig is shown in FIG. 4a in sectional view. In this example, water passes through the wall plate 61, which is a control plate for controlling the flow rate, from the water supply port 51, enters the wafer 1 laterally to the wafer 1, and mainly overflows from the left wall plate.
The structure of the wall plate 61 is as shown in the plan view in FIG. In the corresponding part of the wall board, and at the water inlet 5
1, a large hole 75 with a diameter of about 8 mm is formed in the other part, a medium hole 74 with a diameter of about 6 mm in the other part, and a small hole 76 in the other part, that is, an area that does not correspond to the wafer. Approximately 5mm
Provide a φ flow port. In this case, water flows from the bottom right to the top left, so we made many large holes on the bottom of the wallboard to ensure an even flow and a roughly even cleaning effect.

According to the configuration of the present invention, the cleaning effect can be achieved by distributing and allocating the amount of water to the object to be cleaned to the extent that as much water as possible is sent and water does not stagnate in other parts. It has advantages such as saving water amount and shortening cleaning time.

[Brief explanation of the drawing]

1A and 1B are cross-sectional views of a cleaning tank for explaining a conventional example, FIG. 1C is a plan view of the bottom plate of the cleaning tank of the conventional example, and FIGS. FIG. 4a is a sectional view of the cleaning tank of another embodiment, and FIG. 4b is a plan view of the main parts of the same embodiment. 1... Wafer to be cleaned, 2... Cleaning jig, 3
...Cleaning tank, 5,51...Water supply port, 6...Bottom plate,
61...Wall plate (flow control plate), 7, 71, 72,
73, 74, 75, 76...hole.

Claims (1)

[Claims] 1. A control plate for controlling the flow rate is provided on the water supply port side, a plurality of flow ports are provided on the control board, and the effective flow opening area of the flow ports is set at a position corresponding to the object to be cleaned. A cleaning tank characterized in that the cleaning tank is made larger at a position further away from the water supply port, and further enlarged at a position farther from the water supply port. 2. The cleaning tank according to claim 1, in which the diameter of the flow port of the control board increases as the distance from the water supply port increases. 3. The cleaning tank according to claim 1, wherein the flow port of the control board has a constant diameter, and the density increases as the distance from the water supply port increases.