JPH0750264A - Semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE:To form a polycrystal film (e.g. a polycrystalline silicon film) provided with sufficiently large crystal grain diameter which can obtain high film formation speed when an amorphous film (e.g. amorphous silicon film) is formed at a low temperature. CONSTITUTION:In a reaction chamber 3 of a semiconductor manufacturing equipment for forming a desired film, a plurality of light sources 12 and 13 which apply light different in wavelenth in the range of wavelength shorter than that of visible light to the surface of a wafer 1, and a heater 1 for heating the wafer 1 are installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to a semiconductor manufacturing apparatus for forming a desired film on a wafer which has been subjected to desired processing.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device manufacturing process, on a wafer which has been subjected to desired processing for various purposes,
A polycrystalline silicon film is formed. As an example thereof, for example, a polycrystalline silicon film is formed as a gate electrode forming material, or a thin film transistor (Thin Film) is used.
A polycrystalline silicon film is formed for the purpose of forming a source region and a drain region of a transistor (hereinafter referred to as "TFT").

When forming a gate electrode made of a polycrystalline silicon film, impurities are introduced to reduce the resistance of the polycrystalline silicon film. The impurities segregate at the crystal grain boundaries of the polycrystalline silicon film during the heat treatment performed in a later step, and cause a portion having an uneven impurity concentration in the polycrystalline silicon film. Therefore, a portion with a high impurity concentration locally occurs at the interface between the gate insulating film and the gate electrode (polycrystalline silicon film), and the impurities enter the gate insulating film and diffuse through the gate insulating film to penetrate. There was a problem that dielectric breakdown occurred in this part.

Further, the impurities project from the gate electrode side to the gate insulating film side to reduce the flatness at the interface between the gate insulating film and the gate electrode, and electric field concentration occurs in the projecting portion of the impurities, resulting in gate insulation. There is a problem that the withstand voltage characteristic of the film is deteriorated. Here, since the polycrystalline silicon film formed by the usual method has a small crystal grain size, a large proportion of crystal grain boundaries exist. Therefore, the rate of segregation of the impurities inevitably increases. For this reason, the entry of impurities into the gate insulating film increases, and electric field concentration is likely to occur. Further, the deterioration of the withstand voltage characteristics is more likely to occur more frequently as the film thickness of the gate insulating film becomes thinner, and it is one of the causes that prevent miniaturization of the semiconductor device.

Therefore, in order to solve these problems,
It has been required to form a polycrystalline silicon film having a large crystal grain size. On the other hand, when a polycrystalline silicon film is formed for the purpose of forming the source region and the drain region of the TFT, a channel is formed in the polycrystalline silicon film. In this channel, as the crystal grain size of the polycrystalline silicon film is larger, the mobility of electrons and holes is increased, and the leak current can be controlled (decreased). Therefore, as the crystal grain size of the polycrystalline silicon film is increased, the channel characteristics can be improved.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 2-252245, after forming an amorphous silicon film, heat treatment is performed on the amorphous silicon film to crystallize the amorphous silicon film. There is a method of forming a polycrystalline silicon film having a large crystal grain size.

[0007]

However, in the conventional example disclosed in Japanese Patent Application Laid-Open No. 2-252245, the amorphous silicon film is formed at a low temperature, so that the film forming speed is slow and the productivity is improved. There was a problem that I could not do it. In addition, there is also a problem that if the film formation rate of the amorphous silicon film is slow, coarsening of the formed grain size is hindered.

An object of the present invention is to solve such a conventional problem, and even if an amorphous film (for example, an amorphous silicon film) is formed at a low temperature, high performance is achieved. Provided is a semiconductor manufacturing apparatus capable of obtaining a film speed and capable of forming a polycrystal film (for example, a polycrystal silicon film) having a sufficiently large crystal grain size when crystallized. That is the purpose.

[0009]

In order to achieve this object, the present invention is a semiconductor manufacturing apparatus for forming a desired film on a surface of a wafer, which is shorter than visible light and has wavelengths different from each other. A plurality of light irradiation means for irradiating the surface of the wafer with light, and a wafer heating means for heating the wafer,
The present invention provides a semiconductor manufacturing apparatus characterized by including.

[0010]

In the semiconductor manufacturing apparatus according to the present invention, when a desired film is formed on a wafer, a plurality of lights each having a shorter wavelength than visible light and different wavelength regions are irradiated to the wafer surface. A fluid such as a source gas used for the film and a film formation site are multiphoton excited. Therefore, the reactivity performed during film formation is improved. Further, the semiconductor manufacturing apparatus according to the present invention,
Since the heating means for heating the wafer is provided, the reactivity performed during the film formation is further improved. Therefore, a high film formation rate can be obtained even when the film formation temperature is low.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a semiconductor manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 shows a process of forming a film on a wafer which has been subjected to desired processing, using the semiconductor manufacturing apparatus shown in FIG. It is a fragmentary sectional view shown.

The semiconductor manufacturing apparatus 20 shown in FIG. 1 is provided with a reaction chamber 3 that can be hermetically sealed and that can accommodate a wafer 1. A wafer mounting table 2 for mounting the wafer 1 is disposed in the reaction chamber 3, and a heater 4 for heating the wafer 1 mounted on the wafer mounting table 2 is provided on the lower surface of the wafer mounting table 2.
Is provided. In this embodiment, the heater 4
Corresponds to the heating means according to claim 1.

A gas cylinder 6 which is a supply source of a source gas used for film formation is connected to the reaction chamber 3 through an opening / closing valve 5. A molecular pump 8 for depressurizing the reaction chamber 3 is connected to the reaction chamber 3 via an opening / closing valve 7, and an oil rotary pump 9 is connected to the molecular pump 8. And, in the hydraulic rotary pump 9,
A waste gas treatment chamber 10 for treating the waste gas sucked from the reaction chamber 3 by the molecular pump 8 and the oil rotary pump 9 is connected.

Further, in the reaction chamber 3, at a position facing the wafer 1 mounting surface of the wafer mounting table 2, 400 to 6 are provided.
A xenon lamp 12 for irradiating light with a wavelength of 00 nm;
An ultra-high pressure mercury lamp 13 that irradiates light with a wavelength of 200 to 300 nm is provided. That is, the xenon lamp 12
The ultra-high pressure mercury lamp 13 is arranged at a position where the light emitted from the lamp can reach the surface of the wafer 1 mounted on the wafer mounting table 2. In addition,
In this embodiment, the xenon lamp 12 and the ultra-high pressure mercury lamp 13 correspond to the light irradiating means.

The xenon lamp 12 and the ultra-high pressure mercury lamp 13 are housed in the cooling duct 11 to prevent the xenon lamp 12 and the ultra-high pressure mercury lamp 13 from raising the temperature in the reaction chamber 3. . The cooling duct 11 includes a xenon lamp 12 and an ultra-high pressure mercury lamp 1.
3 is provided with a material that does not interfere with the property of the light radiated from the wafer 3 onto the wafer 1.

Next, the semiconductor manufacturing apparatus 20 according to the present embodiment.
A method of forming an amorphous silicon film on the wafer 1 that has been subjected to a desired process by using will be described. Figure 2
In the step shown in (1), the wafer 1 having the insulating film 32 formed thereon is placed on the wafer placing table 2 of the semiconductor manufacturing apparatus 20. Next, in the step shown in FIG. 2B, the on-off valve 7 is opened and the molecular pump 8 and the oil rotary pump 9 are operated to move the reaction chamber 3
Decompress the inside. Next, the opening / closing valve 5 is opened, and Si ₂ H ₆ is introduced into the reaction chamber 3 from the gas cylinder ₆ at a flow rate of 20 sccm.

Next, the xenon lamp 12 and the ultra-high pressure mercury lamp 13 are operated, and the xenon lamps 12 to 400 are activated.
Light having a wavelength of ˜600 nm is simultaneously irradiated from the ultrahigh pressure mercury lamp 13 to light having a wavelength of 200 to 300 nm on the insulating film 32 formed on the wafer 1. At the same time, the heater 8 is operated to heat the wafer 1 to about 480 ° C., and the amorphous silicon film 33 having a thickness of about 150 nm is formed on the insulating film 32 formed on the wafer 1. To form.

At this time, the light emitted from the xenon lamp 12 and the ultra-high pressure mercury lamp 13 multiphoton-excites the film formation sites of the Si ₂ H ₆ and the amorphous silicon film 33, so that the film formation reactivity is high. Can be improved. Further, by heating the wafer 1 with the heater 4, the reactivity of film formation can be further improved. Therefore, even if the film forming temperature is low, a high film forming rate can be obtained, and the amorphous silicon film 33 can be formed in a short time. The film forming time at this time was 1 hour, and the film forming rate of the amorphous silicon film 33 was 2.5 nm / min.

In this step, the waste gas stored in the waste gas treatment chamber 10 from the molecular pump 8 and the oil rotary pump 9 is subjected to a predetermined treatment here. Next, FIG. 2 (3)
In the process shown in (1), the xenon lamp 12 and the ultra-high pressure mercury lamp 13 are turned off, the on-off valve 5 is closed, the introduction of Si ₂ H ₆ is stopped, the on-off valve 7 is closed, and the inside of the reaction chamber 3 is returned to normal pressure. . Next, nitrogen gas is introduced into the reaction chamber 3 from another gas cylinder (not shown), the temperature of the heater 4 is raised, and the wafer 1 is heated to about 650 ° C.
Crystallize. The time required for this crystallization was 5 hours. In this way, the crystal grain size is 2-3 μm.
A polycrystalline silicon film 34 having a certain degree was formed.

After that, although not particularly shown, this polycrystalline silicon film 34 is used as a gate electrode forming material, and BF ₂ as impurities is added to this as a dopant amount = 2 × 10 ¹⁵ cm 2.
^-2 , ion implantation is performed with energy = 40 KeV to reduce the resistance, and then patterning is performed to form a gate electrode.
Next, using a rapid heating device, the wafer 1 on which the gate electrode is formed has a heating temperature of 1050 ° C. and a heating time of 20.
Second heat treatment is performed to activate the impurities.

Thereafter, desired steps are performed to complete the semiconductor device. Next, as a comparison, in the step shown in FIG.
When the amorphous silicon film was formed without operating the xenon lamp 12, the ultra-high pressure mercury lamp 13 and the heater 4,
The film formation rate of the amorphous silicon film was 0.6 nm / min. Therefore, when the amorphous silicon film is formed by using the semiconductor manufacturing apparatus 20 according to the present embodiment, the film formation speed is 4 times or more as compared with the case where the amorphous silicon film is formed by the conventional method. It can be seen that

Next, the amorphous silicon film formed by the conventional method was crystallized in the same manner as in the step shown in FIG. 2C, and the crystal grain size was 0.1 to 0.5 μm. A polycrystalline silicon film having a certain degree was obtained. Therefore, the amorphous silicon film formed by using the semiconductor manufacturing apparatus 20 according to the present embodiment is a polycrystalline silicon film having an extremely large crystal grain size as compared with the amorphous silicon film formed by the conventional method. It turns out that a film can be formed.

Next, after crystallizing the amorphous silicon film formed by the conventional method, the same steps as described above are performed to complete the semiconductor device (conventional product). Next, the sheet resistance of the gate electrode was investigated for the semiconductor device (invention product) according to this example and the conventional product. Moreover, the yield of the initial withstand voltage of the gate insulating film was investigated for the invention product and the conventional product. The results are shown in Table 1.

[0024]

[Table 1]

From Table 1, it was confirmed that the sheet resistance of the gate electrode of the invention product was significantly lower than that of the conventional product. Further, it was confirmed that the invented product significantly improved the yield of the initial withstand voltage of the gate insulating film as compared with the conventional product. This is because in the invention product, the crystal grain size of the polycrystalline silicon film, which is the material for forming the gate electrode, is significantly coarser than that of the conventional product, so that the proportion of crystal grain boundaries is reduced and the resistance is reduced. This is because the ratio of the impurities doped into the polycrystalline silicon film to be segregated can be reduced, and the factors that cause the dielectric breakdown of the gate insulating film and the deterioration of the withstand voltage characteristic can be reduced.

In this embodiment, the light irradiation means is
Although the xenon lamp 12 and the ultra-high pressure mercury lamp 13 are provided, the present invention is not limited to this, and any other light source may be used as long as it is possible to irradiate the surface of the wafer 1 with light shorter than visible light and having wavelengths different from each other. Etc. may be used. Further, although two light sources are provided in the present embodiment, the present invention is not limited to this, and if light of shorter wavelength than visible light and different wavelength regions is irradiated, three or more light sources are provided to perform multi-stage excitation. You may go.

The light irradiation means may be arranged at any position as long as the light emitted from the light irradiation means can reach the surface of the wafer 1. Further, in the present embodiment, the heater 4 is provided as the wafer heating means, but the present invention is not limited to this, and another device may be used as long as the wafer 1 can be heated without disturbing film formation. May be used.

In this embodiment, Si ₂ H is used as a source gas for forming the amorphous silicon film 33.
₆ was used, but not limited to this, SiH ₄ , Si ₃ H ₈
May be used. Then, in this embodiment, nitrogen gas was used when crystallizing the amorphous silicon film 33,
Not limited to this, oxygen or argon gas, or nitrogen gas,
Any one or more of oxygen and argon gas may be used.

Further, although the case of forming an amorphous silicon film has been described in the present embodiment, the present invention is not limited to this, and the semiconductor manufacturing apparatus according to the present invention is not limited to visible light and has light of different wavelength regions. Any film can be applied as long as it is a film whose film forming characteristics are improved by irradiating with. In addition, in the present embodiment, the case where the formed polycrystalline silicon film is used as the gate electrode has been described, but the present invention is not limited to this, and the polycrystalline silicon film formed by using the semiconductor manufacturing apparatus according to the present invention is As long as it is formed of a polycrystalline silicon film, such as used as a source and drain region forming material of a TFT, it can be used for various purposes.

This embodiment is merely an example, and the film formation time, film formation temperature, film thickness, impurity type, impurity dose amount and implantation energy, and activation of the implanted impurities are described. The heat treatment temperature and time for performing the heat treatment are not limited thereto.

[0031]

As described above, in the semiconductor manufacturing apparatus according to the present invention, when a desired film is formed on a wafer, a plurality of lights each having a shorter wavelength than visible light and different wavelength regions from each other are used.
Since the wafer surface can be irradiated, multiphoton excitation can be performed on a fluid such as a source gas used for film formation and a film formation site. Therefore, the reactivity performed during film formation can be improved. Further, since the heating means for heating the wafer is provided, the reactivity performed during the film formation can be further improved. As a result, the amorphous film can be formed at a high film forming rate even when the film forming temperature is low, and the productivity can be significantly improved.

When this amorphous film is crystallized,
A polycrystalline film having a large crystal grain size can be obtained.
When a polycrystalline silicon film is formed, it can be used as a gate electrode forming material to improve the reliability of the gate oxide film,
The resistance of the gate electrode can be improved to be low, and when it is used as the material for forming the source and drain regions of the TFT, excellent channel characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a step of forming a film on a wafer which has been subjected to desired processing, using the semiconductor manufacturing apparatus shown in FIG.

[Explanation of symbols]

 1 wafer 2 wafer mounting table 3 reaction chamber 4 heater 5 on-off valve 6 gas cylinder 7 on-off valve 8 molecular pump 9 oil rotary pump 10 waste gas treatment chamber 11 cooling duct 12 xenon lamp 13 ultra-high pressure mercury lamp 20 semiconductor manufacturing device 32 insulating film 33 Amorphous silicon film 34 Polycrystalline silicon film

Front page continuation (72) Inventor Yoshikatsu Shida 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Corporation Technical Research Division (72) Inventor Junichi Kawaguchi 1, Kawasaki-cho, Chuo-ku, Chiba Prefecture Kawasaki Steel Technology Research Headquarters (72) Inventor Yoshio Kaneko 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Engineering Research Headquarters

Claims (1)

[Claims] 1. A semiconductor manufacturing apparatus for depositing a desired film on a surface of a wafer, comprising: a plurality of light irradiating means for irradiating the surface of the wafer with light shorter than visible light and having wavelengths different from each other. A semiconductor manufacturing apparatus comprising: a wafer heating unit that heats the wafer.