JPH03233930A - Cleaning method for semiconductor device - Google Patents

Abstract

PURPOSE:To decide the cleaning time which is necessary and sufficient by a method wherein a means to detect the quality of a cleaning liquid is installed inside a cleaning tank and the cleaning time is controlled by detecting that the quality of the cleaning liquid is returned to an initial state. CONSTITUTION:A resistivity detector 2b is installed near a cleaningliquid discharge port 1b inside a cleaning tank 1; the resistivity of pure water during a cleaning treatment is measured by using a resistivity meter main body 2a connected to the resistivity detector 2b. When a semiconductor wafer 4 is cleaned in this state, a chemical liquid which is adhered to the semiconductor wafer 4 is diffused into the pure water, and a resistivity value is once made small. As a cleaning process progresses, the resistivity value becomes large. When the value becomes nearly equal to the resistivity value of the pure water in an initial stage, this means that the semiconductor wafer 4 has been cleaned completely. At this time, the cleaning process is finished. Thereby, an object to be cleaned can be cleaned in the cleaning time which is necessary and sufficient; the quality of the object to be cleaned can be ensured without using a wasteful cleaning liquid.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for managing a necessary and sufficient cleaning time in a semiconductor device cleaning process, the present invention provides a method for cleaning a semiconductor device that makes it possible to determine a necessary and sufficient cleaning time. In a method for cleaning the object by placing an object to be cleaned in a cleaning tank, supplying a cleaning liquid from a cleaning liquid supply port of the cleaning tank, and discharging the cleaning liquid from a cleaning liquid outlet, the method includes: A means for detecting the quality of the cleaning liquid is provided in the cleaning tank, and cleaning time is managed by detecting that the quality of the cleaning liquid has returned to its initial state.

[Industrial application field]

The present invention relates to a method for managing necessary and sufficient cleaning time in a semiconductor device cleaning process.

2. Description of the Related Art In recent years, in the manufacturing process of semiconductor devices where element patterns have become denser and semiconductor substrates have larger diameters, it has become necessary to appropriately clean the semiconductor substrates.

Under the above circumstances, there is a need for a method of cleaning semiconductor devices that can appropriately perform cleaning processing of semiconductor devices.

[Conventional technology]

A conventional method for cleaning semiconductor devices will be explained with reference to FIG.

The cleaning tank 11 used for cleaning processing in the conventional manufacturing process of semiconductor devices has a cleaning liquid supply port 11a as shown in FIG.
A wafer basket 3 carrying semiconductor wafers 4 is placed on a partition plate 11c inside the cleaning tank 11. Partition Fillcl
This is provided with small holes through which pure water passes, creating an upward water flow as indicated by the arrow in the figure.

Pure water is supplied from this cleaning liquid supply port 11a, and the partition plate 11
The upward flow of pure water that has passed through the small hole c removes the chemical liquid etc. that adhered to the semiconductor wafer 4 in the previous process,
Pure water is overflowed and discharged from the cleaning liquid discharge port 11b.

In this case, in order to ensure the quality of the object to be cleaned, the cleaning time tends to become longer each time a problem occurs in which the chemical solution remains on the semiconductor wafer.

[Problem to be solved by the invention]

In the conventional semiconductor device cleaning method described above, it is difficult to determine an appropriate cleaning time, so each time a problem occurs where the chemical solution remains on the semiconductor wafer, the cleaning time becomes longer and the amount of purified water used increases. There was a problem with the increase.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention aims to provide a method for cleaning semiconductor devices, which makes it possible to determine a necessary and sufficient cleaning time.

[Means to solve the problem]

In the method for cleaning semiconductor devices of the present invention, an object to be cleaned is placed in a cleaning tank, a cleaning liquid is supplied from a cleaning liquid supply port of the cleaning tank, and the cleaning liquid is discharged from a cleaning liquid outlet to clean the object. In the cleaning method, means for detecting the quality of the cleaning liquid is provided in the cleaning tank, and the cleaning time is managed by detecting that the quality of the cleaning liquid has returned to its initial state.

4 [Function] That is, in the present invention, the object to be cleaned is placed in a cleaning tank, the cleaning liquid is supplied from the cleaning liquid supply port of the cleaning tank, and the object is cleaned by an upward water flow passing through the small hole of the partition plate 1c. The cleaning object is cleaned to remove the chemical liquid etc. that adhered to the semiconductor wafer 4 in the previous process, and a means for detecting the quality of this cleaning liquid is provided in this cleaning tank, so that the quality of the cleaning liquid returns to its initial state. Since it is possible to detect this by this means, it becomes possible to appropriately manage the cleaning time.

〔Example〕

Hereinafter, a method for cleaning a semiconductor device according to an embodiment of the present invention will be explained in detail with reference to FIG.

The cleaning tank 1 used in the cleaning process of this embodiment in the manufacturing process of semiconductor devices has a cleaning liquid supply port 1a as shown in FIG.
A wafer basket 3 carrying semiconductor wafers 4 is placed on a partition plate IC in the cleaning tank 1. The partition plate IC is provided with small holes through which pure water passes, so that an upward water flow is generated as shown by the arrow in the figure.

A cleaning liquid, in this embodiment, pure water, is supplied from this cleaning liquid supply port 1a, and the chemical liquid etc. that adhered to the semiconductor wafer 4 in the previous process is removed by the upward flow of pure water that has passed through the small holes of the partition plate 1c. Water is overflowed and discharged from the cleaning liquid discharge port 1b.

In this embodiment, a resistivity detector 2b is provided near the cleaning liquid outlet 1b in the cleaning tank 1, and the resistivity meter main body 2a connected to the resistivity detector 2b measures the resistivity of pure water during the cleaning process. Measured by

When the semiconductor wafer 4 is cleaned in such a state, the chemical solution adhering to the semiconductor wafer 4 is diffused into the pure water, and the resistivity value becomes small once, and as the cleaning process progresses, this resistivity value decreases. If the resistivity becomes large and almost the same as the initial resistivity of pure water, it means that the semiconductor wafer 4 has been completely cleaned, and if the cleaning process is ended at this point,
It is possible to prevent the quality of the semiconductor wafer 4 from deteriorating due to contamination of the semiconductor wafer 4 with the chemical liquid by using the minimum amount of pure water.

In this embodiment, the cleaning time is managed by the specific resistance value, but it is also possible to manage the cleaning time by measuring the PH value of pure water using a PI meter.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by providing an extremely simple means for detecting the quality of the cleaning liquid in the cleaning tank, it is possible to detect that the quality of the cleaning liquid has returned to its initial state, and to obtain the necessary and sufficient amount of water. It has the advantage of being able to clean the object within the cleaning time, ensuring the quality of the object without using wasted cleaning liquid, and being extremely economical and efficient. , it becomes possible to provide a cleaning method for semiconductor devices that can be expected to have the effect of improving reliability.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cleaning tank used in an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional cleaning tank used for cleaning semiconductor devices. In the figure, 1 is a cleaning tank, 1a is a cleaning liquid supply port, 1b is a cleaning liquid outlet, 1c is a partition plate, 2a is a resistivity meter body, 2b is a resistivity detector, 3 is a wafer basket, 4 is a semiconductor wafer, show.

Claims (1)

[Scope of Claims] An object to be cleaned (4) is placed in a cleaning tank (1), and a cleaning liquid is supplied from a cleaning liquid supply port (1a) of the cleaning tank (1),
In the method of cleaning the object (4) by discharging the cleaning liquid from the cleaning liquid outlet (1b), a means (2b) for detecting the quality of the cleaning liquid is provided in the cleaning tank (1), A method for cleaning a semiconductor device, characterized in that cleaning time is managed by detecting that quality has returned to an initial state.