JPH05275342A - Method and device for forming thin film - Google Patents

Abstract

PURPOSE:To stably form a high quality thin film on the surface of a substrate by relatively simply and surely preventing of a natural oxide film and sticking of moisture on the substrate surface during conveyance of the substrate. CONSTITUTION:At the time of performing prescribed processing (thin film formation) on the surface of a substrate, a protective film is formed on the substrate surface immediately after finishing the preliminary processing, a protective film previously formed on the substrate is removed in advance of performing a prescribed processing (thin film formation) on the surface of the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming method and a thin film forming apparatus used for forming a thin film on a surface of a substrate in a process of manufacturing a semiconductor device such as VLSI.

[0002]

2. Description of the Related Art A thin film forming technique for growing a thin film on the surface of a substrate is one of the key technologies for improving the performance of semiconductor devices, and in particular, the CVD (chemical vapor deposition) method. The thin film growth according to is widely used in the semiconductor manufacturing process.

One of the important points in this thin film growth is the condition on the surface of the substrate (semiconductor wafer or the like). That is, when the condition on the surface of the substrate is bad, it causes various adverse effects such as a case where a desired thin film does not grow, and even when a thin film grows, electrical characteristics and the like may deviate from design values. I will end up. Therefore, it is essential to keep the substrate surface in a desired state before thin film growth.

However, even if the substrate surface is made into a desired state in the previous step of the thin film forming step, if it is transported as it is, the surface of the substrate is naturally oxidized during the substrate transportation until the thin film formation. A film is formed and water is absorbed.

Therefore, conventionally, as a pretreatment for forming a thin film, the natural oxide film formed on the surface of the substrate is removed by etching the surface of the substrate, or the temperature of the atmosphere surrounding the substrate is raised to form a film on the surface of the substrate. It has been common practice to take measures such as evaporating the adsorbed water, or to transport the substrates while they are loaded in a contamination-free N2 box. In addition, recently, it has been proposed to transport a substrate through an N2 tunnel.

By performing the above-mentioned respective processes here,
At present, the condition of the substrate surface is not so problematic, but in the future, when the semiconductor device becomes more highly integrated, the formation of a natural oxide film and the adsorption of moisture during the transportation of the substrate are fatal. It may be a problem, and it is considered that preventing this and maintaining the substrate surface in a desired state will bring about great effects on improvement of throughput, improvement of yield, and improvement of reliability.

[0007]

However, in order to prevent the formation of a natural oxide film and the adsorption of moisture during the transportation of the substrate, in the conventional example in which the substrate is loaded in the N2 box and transported, the substrate is moved into and out of the N2 box. In addition to increasing the chances of contamination of the substrate when changing it, this transfer operation is quite troublesome, and it is insufficient from the standpoint of effect and handling.

Further, in the case where the substrate is transported through the N2 tunnel, not only the cost of the apparatus increases, lack of flexibility, the manufacturing line becomes complicated, etc., but also there is a problem in dealing with troubles. it is conceivable that.

That is, with the remarkable increase in the degree of integration of semiconductor devices, various requirements have been made in the thin film forming technology.
Among these requirements, maintaining the state of the substrate surface is an important technical matter.

In view of the above, the present invention relatively easily and reliably prevents the formation of a natural oxide film and the adsorption of moisture on the surface of a substrate during the transportation of the substrate, and stabilizes a high-quality thin film on the surface of the substrate. It is an object of the present invention to provide a product which can be formed by the above method.

[0011]

In order to achieve the above object, the first thin film forming method of the present invention provides a protective film for protecting the surface of the substrate after the completion of the processing in the first substrate processing step. It is characterized in that it is formed on the surface and then the protective film is removed before the processing of the second substrate processing step.

The second thin film forming method of the present invention is characterized in that a protective film for protecting the surface of the substrate is formed on the surface of the substrate after the processing in a predetermined processing step is completed.

Further, the first thin film forming apparatus of the present invention comprises a container for containing a substrate which has been subjected to a predetermined treatment, and a protective film for protecting the surface of the substrate contained in this container. It is characterized in that it has a protective film forming means formed on the surface of the substrate and a protective film removing means for removing the protective film before performing another treatment on the substrate on which the protective film is formed.

Further, the second thin film forming apparatus of the present invention comprises a container for containing a substrate which has been subjected to a predetermined treatment, and a protective film for protecting the surface of the substrate contained in this container. It has a protective film forming means to form.

[0015]

According to the present invention configured as described above, the substrate is transferred from the previous process to a predetermined (thin film forming) process in a state where the protective film is formed on the surface of the substrate, and therefore the substrate is transferred during this transfer. It is possible to reliably prevent the formation of a natural oxide film on the surface of the and the adsorption of moisture.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a flow chart showing an embodiment of the present invention, in which a protective film is formed on the surface of a substrate immediately after the processing in a pre-process of a predetermined (for example, thin film formation) process is completed.

Examples of the protective film include halides such as fluorides and bromides, organic substances such as resists, and nitride films. When a halide is used as the protective film, hydrogen chloride, hydrogen fluoride, hydrogen bromide, etc., or a combination of chlorine gas, fluorine gas, bromine gas, etc., in liquid or gas form is used as the substrate. To adsorb the substrate or soak the substrate in the liquid. In this case, the adsorption becomes easier when the temperature of the substrate is around room temperature, which is lower than the temperature at the time of forming the thin film.

Further, in addition to the resist, another organic solvent may be used as a protective film by spraying it in a liquid or gas state or immersing the substrate in the organic solvent. Furthermore, when the nitride film is used as the protective film, the substrate is immersed in liquid nitrogen as liquid nitrogen, and the temperature of liquid nitrogen (77K
(About -220 ° C)).

The transfer is carried out with the protective film formed on the surface of the substrate in this way. By carrying out in this way, a natural oxide film is formed on the surface of the substrate during the transfer, It is possible to prevent water from being adsorbed.

FIG. 2 shows an example of a multi-chamber type thin film forming apparatus used for forming a thin film. The thin film forming step will be described with reference to the apparatus shown in FIG. 2 and the flow chart shown in FIG.

The thin film forming apparatus 1 has a total of three processing chambers, that is, a chamber for performing a protective film removing operation (hereinafter referred to as a protective film removing chamber) 2, a processing chamber for performing a thin film forming operation (also a thin film growth chamber) 3, and A processing chamber (also a protective film forming chamber) 4 for performing a protective film forming operation is provided, and each of these chambers 2, 3 and 4 is provided with a substrate transfer means 8 inside through gate valves 5, 6 and 7. Are connected to the respective handler rooms 9. A load lock chamber 10 is connected to the handler chamber 9 via a gate valve 11, and a cassette station 13 is connected to the load lock chamber 10 via a gate valve 12.

Then, a substrate having a protective film formed on the surface thereof, housed in a cassette or the like, and conveyed from a previous step in a clean room or the like is set in the cassette station 13, and the substrate set in the cassette station 13 is set. Are loaded into the load lock chamber 10 one by one in conjunction with the opening and closing of the gate valve 12, and thereafter, the substrates are opened and closed by the substrate transfer means 8 arranged in the handler chamber 9. The protective film is removed from the protective film removing chamber 2 in which the protective film removing operation is performed in conjunction therewith.

This protective film removing operation is carried out by irradiating with ultraviolet rays having a wavelength of, for example, 300 nm or less when the protective film is a fluoride, and when the protective film is a chloride or a bromide, a gas which is turned into a plasma ( H2, O2). In this case, the temperature of the substrate is raised to 800 ° C. or higher, for example. Note that both of the above can be combined. Further, in the case of an organic substance, it is carried out by applying a gas (H2, O2) which has been turned into plasma, and in the case of a nitride film, by raising the temperature of the substrate above the liquid nitrogen temperature.

Then, the substrate from which the protective film thus formed is removed is placed in the thin film growth chamber 3 in which the thin film forming operation is performed by the substrate transfer means 8 in conjunction with opening and closing of the gate valves 5 and 6, and the substrate is predetermined. By performing a predetermined thin film growth while supplying the above gas, a thin film forming operation is performed on the surface of the substrate by vapor phase growth or vapor deposition.

When it is necessary to form a protective film on the surface, such as when the substrate having the thin film formed on the surface is used as a pre-process for forming a further thin film, the protective film is formed on the surface of the substrate in the same manner as described above. .. That is, the substrate having a thin film formed on its surface is placed in the protective film forming chamber 4 in which the substrate transfer means 8 performs the protective film forming operation in conjunction with the opening and closing of the gate valves 6 and 7, and here, in the same manner as described above, A protective film on the surface is formed. In this case, this protective film does not have to be the same as the protective film removed prior to the thin film formation depending on the type of the substrate or the type of the thin film, but may be used as it is if it is a resist. It will be convenient.

Then, the substrate on which a thin film and, if necessary, a protective film are sequentially laminated on the surface as described above, is interlocked with the opening and closing of the gate valves 7, 11 or 6, 11 by the substrate transfer means 8 to load-lock the chamber. It is returned to the inside of 10, and is stored in a cassette or the like in the cassette station 13 in conjunction with opening and closing of the gate valve 12, and then conveyed to the next step.

In the above embodiment, the multi-chamber type is provided with three processing chambers.
The number of processing chambers may be one or two.

That is, two of the protective film removing operation, the thin film forming operation, and the protective film forming operation as required, should be performed in the same chamber, or all three operations should be performed in the same chamber. You can also

Further, at least one of the protective film removing operation and the protective film forming operation may be performed in the handler chamber 9 or the load lock chamber 10.

[0031]

As described above, according to the present invention, after the surface of the substrate is brought into a desired state in the step before the predetermined (thin film formation) step, the protective film is formed on this surface, and in this state By transporting the substrate, it is possible to reliably prevent the formation of a natural oxide film and the adsorption of water on the surface during the transport of the substrate, which ensures the stable formation of a high-quality thin film. be able to.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a schematic view showing an example of a thin film forming apparatus.

[Explanation of symbols]

 1 Thin Film Forming Equipment 2, 3, 4 Processing Chamber 8 Substrate Transfer Means 9 Handler Room 10 Load Lock Room 13 Cassette Station

Claims (5)

[Claims] 1. A protective film for protecting the surface of the substrate is formed on the surface of the substrate after the completion of the processing in the first substrate processing step, and then the protective film is removed before the processing in the second substrate processing step. A thin film forming method characterized by the above. 2. A thin film forming method, which comprises forming a protective film on the surface of the substrate for protecting the surface of the substrate after the processing in a predetermined processing step is completed. 3. A container for containing a substrate that has been subjected to a predetermined treatment, and a protective film forming means for forming a protective film on the surface of the substrate for protecting the surface of the substrate contained in the container. A thin film forming apparatus comprising: a protective film removing unit that removes the protective film before performing another treatment on the substrate on which the protective film is formed. 4. A container comprising a substrate which has been subjected to a predetermined treatment, and a protective film forming means for forming a protective film for protecting the surface of the substrate contained in the container. Characteristic thin film forming apparatus. 5. The thin film forming apparatus according to claim 3, wherein the container forms the protective film in the container after the substrate is subjected to the predetermined treatment.