JPH02106927A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce a processing temperature by removing carbon adhered on the surface of a silicon substrate with ozone, and further removing an oxide film adhered on the surface of the substrate with hydrogen fluoride gas. CONSTITUTION:Carbon (containing organic material) on a silicon substrate S is reacted with ozone to become carbon monoxide, carbon dioxide, and other oxygen compound to be removed in ozone process. In this case, the silicon of the substrate S is reacted with the ozone to generate solid silicon dioxide film. In the hydrogen fluoride process after the ozone process, the oxide film (spontaneous oxide film and generated silicon dioxide film) on the substrate S is reacted with the hydrogen fluoride to become gaseous silicon tetrafluoride and steam to be removed. Thus, the substrate S is effectively purified at the low processing temperature.

Description

[Detailed Description of the Invention] [Summary] Regarding a method of cleaning a silicon substrate using a dry process in the manufacture of semiconductor devices, the purpose of this method is to remove carbon on the surface of the substrate using ozone, with the aim of lowering the processing temperature. Further, the oxide film on the surface of the substrate is removed using hydrogen fluoride gas.

[Industrial application field]

The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of cleaning a silicon substrate using a dry process.

In the manufacture of semiconductor devices, there is a process of depositing various films on a silicon substrate. Examples include depositing a semiconductor film on a silicon substrate, depositing an insulating film on a silicon substrate, and depositing an electrode film on a silicon substrate having an insulating film provided with a window on its surface.

When depositing these films, it is necessary to clean the substrate as a pretreatment, and since the above-mentioned deposition is performed by a dry process, the substrate is also cleaned by a dry process.

[Conventional technology]

As the above-mentioned pre-treatment, the conventional method of cleaning a silicon substrate by a dry process is to heat the substrate in a processing chamber and introduce hydrogen chloride (HCI) gas to etch the surface of the substrate. (H2) is introduced to remove the oxide film (natural oxide film) on the surface, and in either case, the processing temperature needs to be about 1100°C.

[Problem to be solved by the invention]

On the other hand, as the performance of semiconductor devices increases, film deposition processes require lower processing temperatures to reduce damage to the substrate. For example, in the case of silicon deposition by CVD (chemical vapor deposition), conventional It has become possible to raise the treatment temperature, which used to be about 600°C, to about 600°C by using disilane (SizHs).

For this reason, the above-mentioned pretreatment has been left behind in lowering the temperature.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to lower the processing temperature in a method for cleaning a silicon substrate using a dry process in the manufacture of semiconductor devices.

[Means to solve the problem]

The above object is achieved by the method of the present invention, which removes carbon on the surface of a silicon substrate using ozone (03) and further removes an oxide film on the surface of the substrate using hydrogen fluoride (HF) gas.

[Function] The above ozone treatment and hydrogen fluoride treatment operate as follows even if the treatment temperature is as low as about 450°C. That is, in the ozone treatment, carbon (including organic substances) on the silicon substrate reacts with ozone to become gaseous carbon monoxide, carbon dioxide, and other oxygen compounds and is removed. At this time, the silicon of the substrate reacts with ozone to form a solid silicon dioxide film.

Then, in the hydrogen fluoride treatment after the ozone treatment, the oxide film (natural oxide film and the silicon dioxide film generated above) on the substrate reacts with the hydrogen fluoride and becomes gaseous silicon tetrafluoride and water vapor and is removed. Ru.

Thus, the silicon substrate can be reliably cleaned at low processing temperatures.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. Fig. 1 is a process diagram of an example of substrate cleaning performed before film deposition, Fig. 2 is a configuration diagram of an example of a substrate cleaning apparatus for carrying out the example, and Fig. 3 is a diagram showing the structure of an example of a substrate cleaning apparatus used in the embodiment. FIG. 3 is a configuration diagram showing a connection.

In FIG. 1, ozone treatment is first performed, followed by hydrogen fluoride treatment to complete substrate cleaning, and then film deposition is performed.

In ozone treatment, a silicon substrate is heated to a treatment temperature in a normal pressure treatment chamber in a nitrogen (N2) atmosphere, and ozone is introduced therein. The ozone generated by an ozone generator was used at a flow rate of about 500 cc/min, the processing temperature was about 450° C., and the processing time was about 5 minutes.

After processing, the inside of the processing chamber is returned to a nitrogen atmosphere.

In the hydrogen fluoride treatment, hydrogen fluoride gas is introduced after the ozone treatment. Hydrogen fluoride gas was generated by bubbling nitrogen into an aqueous hydrogen fluoride solution at about 60°C, with a flow rate of about 2QOcc/min, and a treatment temperature of about 45°C.
At 0°C, the processing time is about 5 minutes.

After processing, the inside of the processing chamber is returned to a nitrogen atmosphere.

The ozone treatment and hydrogen fluoride treatment work as described above to reliably clean the silicon substrate.

In this case, the silicon substrate may not only have the entire surface exposed to silicon, but also may have an insulating film with a window on the surface so that the silicon is only partially exposed.The insulating film may be made of silicon dioxide. This is because in some cases, only a thin layer of the upper layer of the insulating film is removed.

The substrate cleaning described above can be performed, for example, by the substrate cleaning apparatus 100 shown in the block diagram of FIG. 2.

In FIG. 2, 101 is a processing chamber, 102 is an inlet/outlet for silicon substrate S, 103 is an inlet for introduction gas,
104 is a dispersion plate that allows the introduced gas to uniformly hit the substrate S, 105 is an exhaust port, 106 is a heater that heats the substrate S, 107 is an ozone generator that generates ozone, 108
109 is a nitrogen supply pipe, 110 is a flow rate regulator, and 111 is a valve. This device 100 performs single-wafer processing for cleaning the substrate S. Do it with

It is desirable that the silicon substrate that has been cleaned as described above is not exposed to the atmosphere until film deposition is performed.

This can be realized by connecting the substrate cleaning apparatus 100 to a film deposition apparatus as shown in the block diagram of FIG.

In FIG. 3, reference numeral 200 denotes a single-wafer processing type film deposition apparatus, and the film may be deposited by any method such as CVD, sputtering, or vapor deposition.

The substrate cleaning apparatus 100 and the film deposition apparatus 200 are coupled by having their respective substrate loading/unloading ports 102 and 202 facing each other, with a load lock 300 interposed therebetween.

A substrate transport mechanism 301 is located inside the load lock 300.
is provided, and the substrate S is moved in and out between the outside and the load lock 300 by the operation of the transport mechanism 301, between the load rotor 300 and the substrate cleaning apparatus 100, and between the load lock 300 and the film deposition apparatus 200. do.

Therefore, due to the presence of the load lock 300, even if the film deposition apparatus 200 requires reduced pressure, film deposition will not be hindered.

〔Effect of the invention〕

As explained above, according to the configuration of the present invention, it is possible to lower the processing temperature in a method of cleaning a silicon substrate using a dry process in the manufacture of semiconductor devices, and, for example, reduce damage to the substrate. As a pretreatment for the film deposition step in which the temperature is lowered in order to reduce the temperature, this pretreatment has the effect of making it possible to reduce the above-mentioned damage.

[Brief explanation of drawings]

Figure 1 is a process diagram of an example of substrate cleaning performed before film deposition, Figure 2 is a block diagram of an example of a substrate cleaning apparatus for carrying out the example, and Figure 3 is a diagram of the apparatus shown in Figure 2 and a film deposition apparatus. This is a configuration diagram showing the connection. In the figure, S is a silicon substrate, 100 is a substrate cleaning device, 101 is a processing chamber, 107 is an ozone generator, 108 is a hydrogen fluoride gas generator, 109 is a nitrogen supply pipe, 200 is a film deposition device, 300 is a load Lock, is. 1st rope 2nd 12th f of the best example of a mo-yaku-o-ka performed on Atsushi tm note. 01's (娨截尤a voice 2 mouths)

Claims (1)

[Claims] 1. A method for manufacturing a semiconductor device, which comprises, when cleaning a silicon substrate by a dry process, removing carbon on the surface of the substrate with ozone and further removing an oxide film on the surface of the substrate with hydrogen fluoride gas.