JPS617633A - Purifier of semiconductor wafer by pure water - Google Patents

Abstract

PURPOSE:To improve the purifying effect by a method wherein wafers in a vessel are supplied with pure water at the bottom of the vessel simultaneously with inert gas. CONSTITUTION:A stage 16 is loaded with a carrier 3' containing wafers 4 and then pure water (a) is introduced from a tube 12 at the bottom of a vessel 11 while inert gas is simultaneously introduced from another tube 13 for bubbling. Through these procedures, purifying effect may be improved cutting down wafer cost due to reduction of purifying time as well as consumption of pure water since the purifying effect by pure water may be further improved by physical purifying action by inert gas (b).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an apparatus for cleaning semiconductor wafers with pure water.

[Technical background of the invention]

A high degree of cleanliness is required for wafer-shaped semiconductor substrates, ie, semiconductor wafers, used for manufacturing semiconductor devices such as ICs and LSIs. For this reason, semiconductor wafers are sent to a cleaning process to be cleaned before forming elements such as transistors therein, and this cleaning process consists of cleaning with chemicals and subsequent cleaning with pure water.

Incidentally, the pure water cleaning described above has conventionally been carried out using an apparatus shown in FIG. In the figure, 1 is a cleaning tank.

The washing 411 is open at the top and connected to the pure water supply pipe 2 at the bottom.

When cleaning semiconductor wafers using this equipment, wafer 3
... is housed in the cleaning tank 1 along with the carrier 4, and the supply pipe 2
This is done by continuously supplying pure water from the As a result, the pure water is transferred to the semiconductor wafer 3 as shown by the arrow in the figure.
. . rises in the cleaning tank 1 from below and overflows, washing away impurities such as chemicals adhering to the semiconductor wafers 3 . In this case, the extent to which the semiconductor wafers 3... have been cleaned is determined by measuring the specific resistance value of the overflow water, and when the specific resistance value of the overflow water has decreased to the value of the supplied pure water, the cleaning is performed. complete.

In addition to the above-mentioned overflow complete cleaning equipment, -FRI
A repeat type cleaning device has also been used in the past, in which all of the pure water in the cleaning tank 1 is flowed out after overflowing, and overflowing is performed again. This repeat-type pure water cleaning device has a structure in which a drain is provided in a part of the cleaning tank 1 in the overflow complete cleaning device shown in Fig. 1, and a passive on-off valve operated by a timer is attached to the drain. There is.

[Problems with background technology]

The conventional pure water cleaning device described above has a problem of low cleaning efficiency. For example, in the case of the overflow complete cleaning equipment shown in Figure 2, past results show that it will take until cleaning is complete, although it depends on the size of the cleaning tank and jig, the number of semiconductor wafers to be cleaned at one time, and the supply pressure of pure water. The process takes about 15 minutes or more, and the amount of pure water consumed during that time cannot be underestimated.

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides a deionized water cleaning device for semiconductor wafers that makes it possible to shorten the cleaning time and reduce the amount of deionized water used, thereby reducing the cost of semiconductor wafers. This was done with the aim of making it possible to reduce the amount of water used.

[Summary of the invention]

A deionized water cleaning device for semiconductor wafers according to the present invention includes a cleaning tank for accommodating semiconductor wafers to be cleaned, a deionized water supply pipe for supplying pure water into the cleaning tank, and a deionized water supply pipe for supplying pure water from below the semiconductor wafer into the cleaning tank. and an inert gas supply pipe for supplying an inert gas, and the semiconductor wafer is cleaned while supplying pure water into the cleaning tank and bubbling the inert gas into the pure water. This is a characteristic feature.

As the inert gas in the present invention, nitrogen gas (N2) can be used in addition to rare gases such as argon and helium.

When semiconductor wafers are cleaned using the deionized water cleaning apparatus of the present invention, the forcible cleaning action by bubbling of the above-mentioned inert gas is added, so that the surface of the semiconductor wafer is removed from the surface of the semiconductor wafer, compared to the case where only pure water overflows. Adherences such as chemicals can be removed more efficiently.

Note that the present invention can be applied to both overflow type and repeat type devices.

[Embodiments of the invention]

An embodiment of the present invention will be described below. 'FIG. 1 shows an embodiment of a semiconductor wafer pure water cleaning apparatus using a repeat method to which the present invention is applied. In the same figure,
11 is a cleaning tank. A pure water supply pipe 12 and an inert gas supply pipe 13 are connected to the lower part of the cleaning tank 11.
The inert gas supply pipe 13 is connected to a punching pipe arranged at the bottom of the cleaning tank 11. In addition, the cleaning tank 11
A drain pipe 14 is connected to the lower part of the drain pipe, and an automatic opening/closing valve 15 is provided in the drain pipe. The automatic opening/closing valve 15 opens and closes at predetermined time intervals to discharge the cleaning water filled in the cleaning tank 11. Reference numeral 16 denotes a mesh-like mounting table provided in the cleaning tank.

To clean a semiconductor wafer using the deionized water cleaning device of the above embodiment, the semiconductor wafer 4 is placed on the mounting table 16 while being housed in the carrier 3', and deionized water is introduced from the supply pipe 12. At the same time, an inert gas is introduced from the supply pipe 13, and cleaning is performed by a repeat method. At this time, at the same time as pure water flows, inert gas forms bubbles from the punching pipe and impacts the surfaces of the carrier 3' and the semiconductor wafers 4. As a result of adding the physical cleaning action of the inert gas, the cleaning with pure water works more effectively, resulting in a higher level of cleaning compared to conventional pure water cleaning equipment that does not use inert gas injection. Gain efficiency.

A semiconductor wafer was cleaned using the deionized water cleaning apparatus shown in FIG.
The results shown in curve A in the figure were obtained. In addition, the figure shows a conventional pure water cleaning device with one overflow type (curve X),
'Similar tracking results for each conventional pure water cleaning device (curve Y) using the repeat method are also shown.

As is clear from this result, the cleaning device of the above example has about 1/2 of the conventional one-overflow type cleaning device.
It has become possible to complete pure water cleaning in about 2/3 of the cleaning time of conventional repeat-type cleaning equipment.

〔Effect of the invention〕

As detailed above, by using the deionized water cleaning apparatus for semiconductor wafers according to the present invention, it is possible to shorten the cleaning time and reduce the amount of deionized water used, which in turn makes it possible to reduce the cost of semiconductor wafers, etc. It is possible to obtain the following effects.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of a semiconductor wafer deionized water cleaning apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a conventional deionized water cleaning apparatus using an overflow type, and FIG. FIG. 2 is a diagram showing the results of tracking the progress of semiconductor wafer cleaning until the completion of cleaning of a semiconductor wafer in a pure water cleaning apparatus according to an example and a conventional cleaning apparatus by measuring the specific resistance value of flowing water. 11...Cleaning tank, 12...Pure water supply pipe, 13...
Inert gas supply pipe, 14... Drain pipe, 15... Automatic opening/closing valve, 16... Mounting table, 3'... Wafer carrier, 4... Semiconductor wafer

Claims (1)

[Claims] A cleaning tank that accommodates semiconductor wafers to be cleaned, a pure water supply pipe that supplies pure water into the cleaning tank, and an inert gas supply pipe that supplies inert gas into the cleaning tank from below the semiconductor wafer. is equipped with, supplies pure water into the cleaning tank, and
A pure water cleaning apparatus for semiconductor wafers, characterized in that the semiconductor wafer is cleaned while bubbling an inert gas into the pure water.