JPH05226313A - Cleaning equipment - Google Patents

Abstract

PURPOSE:To provide a cleaning equipment excellent in foreign matter removal effect wherein cleaning liquid is effectively brought into contact with an object to be cleaned. CONSTITUTION:A cleaning equipment for a semiconductor wafer to form an epitaxial layer constitutes in the following; a washing tank 2 for washing a semiconductor wafer 1 being an object to be cleaned, a protective tank 3 for retaining the washing tank 2, a heater 5 for heating cleaning liquid 4 stored in the washing tank 2, and a fixing board for fixing a wafer cartridge 6 to store semiconductor wafers. The washing tank 2 is constituted of heat resistant material like quartz. In order that oxygen 8 generated as the result of chemical reaction of the cleaning liquid by heating may effectively come into contact with a mirror surface 9 of the semiconductor wafer 1, the washing tank 2 is so formed that the bottom surface is inclined at a specified angle to the horizontal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for cleaning a thin plate-like object, and more particularly to a cleaning device for a semiconductor wafer for forming an Epi (Epitaxial) layer in the manufacture of a semiconductor integrated circuit device using a semiconductor wafer. Related to effective technology.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a semiconductor integrated circuit device, a semiconductor thin plate called a wafer has been used, and a fine circuit pattern is sequentially formed on this wafer by a photolithography technique. For this reason, attachment of dust or the like during the manufacturing process is extremely disliked for the wafer as a material.

For example, even in the Epi growth step, the foreign matter adhering to the wafer causes abnormal abnormal growth of the Epi layer called a protrusion, which is the main cause of mask damage in the photoresist step. Reduction is required. For this reason, in the Epi process, wafer cleaning is performed before Epi growth in order to reduce foreign matter adhering to the wafer.

This cleaning method uses NH ₄ OH, H ₂ O ₂ ,
H ₂ O is used as a cleaning liquid, and generally U (Ultrason
ic) It is known as a cleaning method, and as the cleaning action, a hydrolytic action by NH ₄ OH and a physical stripping action by bubbling oxygen generated by the decomposition of H ₂ O ₂ are considered, It is widely used in the manufacture of semiconductor integrated circuit devices.

A technique similar to this is, for example, Ohm Co., Ltd., issued June 20, 1989,
Examples include those described in documents such as "Introduction to Ultrafine Machining" P135 to P136.

[0006]

However, in the prior art as described above, the protrusions generated by the abnormal growth of the Epi layer have a correlation with the wafer-adhering foreign matter before the Epi, and the adhering foreign matter can be reduced. This is an important issue for improving the quality of the Epi-grown wafer.

However, in the conventional cleaning apparatus, the effect of removing minute foreign matter is not sufficient, and a method for further promoting the foreign matter removing action is desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning device which efficiently brings a cleaning liquid into contact with the surface of an object to be cleaned and has an excellent foreign matter removing effect.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the cleaning apparatus of the present invention is a cleaning apparatus including a cleaning tank for cleaning a thin plate-shaped object to be cleaned, and a heater for heating the cleaning liquid stored in the cleaning tank.
The bottom of the cleaning tank is inclined.

In this case, a storage jig for storing the object to be cleaned is fixed by a fixing plate, and the cleaning tank is protected by a heat and chemical resistant tank.

The article to be cleaned is applied to a semiconductor wafer.

[0014]

According to the above-mentioned cleaning device, the bottom of the cleaning tank is inclined with respect to the horizontal direction, so that the surface of the object to be cleaned can be cleaned with the surface thereof being inclined downward, whereby the cleaning liquid can be removed. It is possible to efficiently contact the surface of the object to be cleaned.

In this case, by fixing the storage jig with the fixing plate, it is possible to prevent the storage jig of the object to be cleaned from moving in the inclined cleaning tank, and the cleaning tank is heat-resistant.
The cleaning tank can be protected by being installed in the chemical resistant tank.

Thus, particularly when applied to the cleaning of semiconductor wafers, oxygen generated by the chemical reaction of the cleaning liquid is efficiently brought into contact with the mirror surface of the semiconductor wafer to promote the physical peeling action and to improve the foreign matter removing effect. Can be raised.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing a semiconductor wafer cleaning apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic plan view showing the cleaning apparatus of this embodiment.

First, the configuration of the semiconductor wafer cleaning apparatus of this embodiment will be described with reference to FIGS. 1 and 2.

The cleaning apparatus of this embodiment is, for example, a cleaning apparatus for semiconductor wafers forming an Epi layer, and has a cleaning tank 2 for cleaning a semiconductor wafer (object to be cleaned) 1, and this cleaning tank 2.
Protective tank (heat-resistant / chemical-resistant tank) 3 for holding and cleaning tank 2
It comprises a heater 5 for heating the cleaning liquid 4 stored in and a fixing plate 7 for fixing a wafer cartridge (accommodation jig) 6 for accommodating the semiconductor wafer 1.

The cleaning tank 2 is made of a heat-resistant material such as quartz, and the bottom surface of the cleaning tank 2 is arranged so that the oxygen 8 generated by the chemical reaction of the cleaning liquid 4 by heating efficiently contacts the mirror surface 9 of the semiconductor wafer 1. Are formed to be inclined at a predetermined angle with respect to the horizontal direction.

The protective tank 3 is made of a heat-resistant / chemical-resistant material such as vinyl chloride, and the protective tank 3 holds the cleaning tank 2 whose bottom surface is inclined. It is protected from the external atmosphere and impact, and can be moved while the cleaning tank 2 is held.

The heater 5 is covered with a heat resistant material such as quartz, and has a heater coil 10 for heating therein. The temperature is detected by a temperature sensor (not shown), and the current to the heater coil 10 is controlled so that the temperature is always a predetermined temperature.

In the inclined cleaning tank 2, the fixed plate 7 is
The wafer cartridge 6 is prevented from slipping down, and the semiconductor wafer 1 is positioned at the center where cleaning efficiency is high.

Next, the operation of this embodiment will be described.

When actually cleaning the semiconductor wafer 1, first, H ₂ O is put into the cleaning tank 2 and heated for a predetermined time.
After that, NH ₄ OH and H ₂ O ₂ are added and heated until the temperature of the cleaning liquid 4 reaches, for example, about 70 ° C.

Next, the wafer cartridge 6 containing the semiconductor wafer 1 is immersed in the cleaning liquid 4 in the cleaning tank 2 to perform cleaning for a predetermined time. At this time, the mixing ratio of the cleaning liquid 4 is, for example, H ₂ O ₂ : NH ₄ OH: H ₂ O = 1: 2: 5.

In this case, the action by the above cleaning method is considered to be a physical exfoliation action by bubbling of oxygen 8 generated by the decomposition of H ₂ O _2. Therefore, the foamed oxygen 8 can be efficiently removed by the semiconductor. The contact with the mirror surface 9 of the wafer 1 is a major point in enhancing the foreign substance removing effect.

Therefore, in the present embodiment, the semiconductor wafer 1 stored in the wafer cartridge 6 is used for cleaning.
Since the mirror surface 9 side of the is installed downward, the bubbled oxygen 8 is brought into contact with the mirror surface 9 of the semiconductor wafer 1 and then moved upward along the mirror surface 9 to remove the minute foreign matter. It can be further promoted.

After cleaning, Ep is placed on the semiconductor wafer 1.
It is possible to reduce the protrusion density when performing i-growth and improve the quality of the Epi-grown wafer.

Therefore, according to the cleaning apparatus of this embodiment, the bottom surface of the cleaning tank 2 is formed to be inclined at a predetermined angle with respect to the horizontal direction, so that the mirror surface 9 of the semiconductor wafer 1 is inclined downward. Since it is possible to perform the cleaning in the state where the oxygen is generated, the oxygen 8 generated by the chemical reaction of the cleaning liquid 4 is efficiently brought into contact with the mirror surface 9 of the semiconductor wafer 1 to promote the physical peeling action and improve the foreign substance removing effect. it can.

The invention made by the present inventor has been specifically described above based on the embodiments, but the present invention is not limited to the embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, the cleaning apparatus of this embodiment has been described in the case where the bottom surface of the cleaning tank 2 is provided with an inclination in advance. However, the present invention is not limited to the above embodiment, and the cleaning tank is simply used. It is also widely applicable to the case where an inclining jig or the like is installed on the bottom surface of the to incline.

Further, the inclination angle of the cleaning tank 2 can be appropriately changed in consideration of the foreign matter removing effect, and the fixing plate 7 can be omitted when the wafer cartridge 6 does not slip.

In the above description, the case where the invention made by the present inventor is mainly applied to a cleaning apparatus for a semiconductor wafer, which is the field of use of the invention, has been described. It can be widely applied to general cleaning devices that utilize the physical peeling effect of foaming, such as thin plate-like objects to be cleaned.

[0035]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). By sloping the bottom surface of the cleaning tank for cleaning the thin plate-shaped object to be cleaned, the surface of the object to be cleaned is inclined downward, and oxygen generated by the chemical reaction of the cleaning liquid is transferred to the object to be cleaned. It can be cleaned while efficiently contacting the surface of the.

(2) Especially, when applied to the cleaning of semiconductor wafers, oxygen generated by the chemical reaction of the cleaning liquid is efficiently brought into contact with the mirror surface of the semiconductor wafer to accelerate the physical peeling action and remove foreign matter. Can be improved.

(3) According to the above (1) and (2), it is possible to obtain a cleaning device capable of reducing the number of foreign substances adhering to a semiconductor wafer by removing even minute foreign substances by promoting a physical peeling action. You can

(4) According to the above (1) to (3), for example, when a semiconductor wafer having a reduced number of adhered foreign substances is used and Epi growth is performed on the semiconductor wafer, the Epi protrusion density is reduced to reduce the Epi protrusion density. The quality of the growth wafer can be improved.

(5) Due to the above (1) to (3), for example, when a semiconductor wafer with a reduced number of adhered foreign matters is used, the number of semiconductor pellets obtained in the manufactured semiconductor integrated circuit device can be increased. it can.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a semiconductor wafer cleaning apparatus that is an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a cleaning apparatus of this embodiment.

[Explanation of symbols]

 1 semiconductor wafer (object to be cleaned) 2 cleaning tank 3 protective tank (heat-resistant / chemical-resistant tank) 4 cleaning liquid 5 heater 6 wafer cartridge (storage jig) 7 fixing plate 8 oxygen 9 mirror surface 10 heater coil

Claims (3)

[Claims] 1. A cleaning tank for cleaning a thin plate-like object to be cleaned,
A cleaning device comprising a heater for heating a cleaning liquid stored in the cleaning tank, wherein the oxygen generated by a chemical reaction of the cleaning liquid efficiently contacts the surface of the object to be cleaned. A cleaning device characterized by having an inclined bottom surface. 2. The cleaning apparatus according to claim 1, wherein a storage jig for storing the object to be cleaned is fixed by a fixing plate, and the cleaning tank is protected by a heat and chemical resistant tank. 3. The cleaning device according to claim 1, wherein the cleaning target is a semiconductor wafer.