JPH0726215B2 - Photoexcitation process equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for photoexcitation process such as photo-CVD (photochemical vapor deposition), photo-etching, and photo-doping, and more specifically to a semiconductor device and a semiconductor integrated circuit. The present invention relates to an apparatus for photoexcitation process used for manufacturing.

[Description of Prior Art]

Conventionally, in the manufacture of semiconductor devices and semiconductor integrated circuits, an excimer laser (eximer lasse) is used as a reaction gas.
r) or low-pressure mercury lamp to irradiate high-energy light to generate active species, and form a deposited film by utilizing the gas-phase reaction between the generated active species or the interfacial reaction between active species and the substrate (so-called A method utilizing a photoexcitation process such as photo-CVD, etching (so-called photo-etching), doping with an impurity element (so-called photo-doping), and the like are used. Various devices have been proposed for that purpose, and such devices include a vacuum reaction container provided with a light-transmitting plate for introducing light, a means for introducing a reaction gas into the reaction container, and high energy for the gas. A means for irradiating light and a means for exhausting the inside of the reaction vessel are provided, and the shape of the vacuum reaction vessel is usually a tubular furnace shape, a cylindrical shape, a cubic shape, a pancake shape, etc. It has a wide reaction space above the wafer (substrate) installed inside.

FIG. 3 is a schematic cross-sectional view showing an example of a conventional photoexcitation process apparatus. In the figure, 301 is a vacuum reaction container, 302 is a disk-shaped transparent plate such as quartz glass, and 303 is for maintaining airtightness. A ring-shaped packing made of an elastic body is provided, 305 is a wafer stage for installing the wafer 304, and 306 is a heater for heating the wafer. In the apparatus, the reaction gas is introduced into the chamber 301 via a gas supply pipe 309 equipped with a valve 311. The high-energy light 314 is irradiated from the high-energy generating means 312 provided above the light-transmitting plate 302 to the optical system 313 such as a lens system and the light-transmitting plate 302, and the reactive gas is irradiated to generate active species. . A chemical reaction such as film formation, etching, or doping occurs on the wafer surface due to a vapor phase reaction between the generated active species or between the active species and the undecomposed reaction gas or a surface reaction between the active species and the wafer surface. The reaction gas and active species not used in the reaction are exhausted through an exhaust pipe 310 having a valve 311.

As described above, in the conventional photoexcitation process apparatus, the reaction space A formed in the vacuum reaction container is formed as a large space above the wafer, and the entire apparatus is bulky.

Further, although it is necessary to attach the light transmitting plate 302 to the upper wall of the reaction container, it is necessary to attach the light transmitting plate 302 strictly in order to maintain the vacuum in the reaction container. As shown in FIG.
In most cases, unevenness is formed on the inner surface of the upper wall of the reaction vessel.

When the inner surface of the chamber is uneven as described above, the reaction gas released into the wide reaction space A through the gas supply pipe becomes a turbulent flow due to the unevenness of the inner surface of the reaction vessel, and the reaction gas is uniformly supplied to the wafer surface. There is a problem that it becomes difficult to reproduce the reaction gas supply state.

Further, when the reaction gas is introduced into the reaction space A through the gas supply pipe having one end opened in the reaction container, the gas flow velocity changes due to the rapid expansion of the reaction gas into the space,
Although eddies may be generated, this is also a factor that hinders the uniform supply of the reaction gas to the wafer surface and the reproduction of the reaction gas supply state.

In order to solve these problems, various methods such as devising the shape of the nozzle attached to the gas supply pipe, providing various gas dispersion means, or providing a gas flow path in the reaction vessel have been proposed. , Neither of them is perfect.

Furthermore, since the wafer heating heater for promoting the photochemical reaction is in the vacuum reaction vessel, the reaction gas randomly flows in the vacuum reaction vessel having a wide reaction space due to radiation from the heater and convection. Therefore, it becomes even more difficult to uniformly supply the reaction gas to the wafer surface and reproduce the reaction gas supply state.

In addition, the photochemical reaction is composed of a gas phase reaction and a surface reaction as described above. However, when a wide space is formed above the wafer as in the conventional apparatus, the gas phase reaction is relatively high. There is also a problem that it is difficult to obtain a uniform film thickness and a uniform film quality when forming a deposited film by photo-CVD.

Furthermore, even if the inner surface of the vacuum reaction container is not uneven, the active species come into contact with the inner surface of the reaction container other than the wafer surface or the inner surface of the light-transmitting plate to cause a chemical reaction, resulting in the formation of undesirable deposits. There is also a problem that the translucency of the translucent plate is deteriorated, the manufacturing speed of the semiconductor device or the semiconductor integrated circuit is reduced, and the manufactured semiconductor device or the semiconductor integrated circuit lacks uniformity.

[Object of the Invention]

It is an object of the present invention to solve the above-mentioned problems in a photoexcitation process device and to provide a device for efficiently manufacturing a semiconductor device or semiconductor integrated circuit having a uniform film thickness and film quality. is there.

That is, a main object of the present invention is to provide a photoexcitation process apparatus capable of supplying a uniform reaction gas to a wafer while keeping the flow of the reaction gas in a laminar flow state and reproducing the reaction gas supply state. Especially.

Another object of the present invention is to provide an apparatus for a photoexcitation process that suppresses a gas-phase reaction in a photochemical reaction and promotes a surface reaction to enable the production of a homogeneous and uniform semiconductor device or semiconductor integrated circuit. is there.

[Structure of Invention]

The inventors of the present invention continued their earnest research to solve the above-mentioned problems in the conventional photoexcitation process apparatus, and the vacuum reaction vessel in this type of apparatus was a thin square reaction vessel,
Further, it was found that the reaction gas flow can be made into a laminar flow state by forming the reaction gas introduction port into the thin square reaction container into a rectangular slit shape. Further research continued, but by making the vacuum reaction vessel a thin square reaction vessel, the reaction space above the wafer was narrowed,
It was found that the gas phase reaction in the photochemical reaction can be suppressed and the surface reaction can be promoted.

The present invention has been completed as a result of further research based on the above findings. That is, the apparatus for photoexcitation process of the present invention, a vacuum reaction vessel forming a reaction space,
Means for introducing a reaction gas into the vacuum reaction vessel, means for irradiating the reaction gas with high-energy light through a transparent plate disposed in the vacuum reaction vessel, and means for exhausting the inside of the vacuum reaction vessel. In the apparatus for the photoexcitation process, the vacuum reaction container is a thin-angle reaction container, the inner surface of the thin-angle reaction container and the inner surface of the translucent plate are flush with each other, and the substrate is placed in the reaction space. A means for introducing the reaction gas is a rectangular gas introduction port, in which the surface of the substrate placed on the stage for placing and the inner surface of the thin rectangular reaction vessel are flush with each other to eliminate unevenness on the inner surface. As a result, a step is eliminated at the joint between the gas inlet and the inner surface of the thin rectangular reaction container.

As the high-energy light used in the photoexcitation process apparatus of the present invention, for example, a light source generated by a mercury lamp, a xenon lamp, a carbon dioxide gas laser, an argon ion laser, a nitrogen laser, an excimer laser, or the like is used.

Further, the reaction gas used in the apparatus of the present invention is selected and introduced depending on the type of semiconductor device and semiconductor integrated circuit to be manufactured. It

The photoexcitation process apparatus having the above-described structure of the present invention will be described in detail below with reference to the embodiments of the drawings. The present invention is not limited to the embodiments shown in the drawings.

FIG. 1 is a schematic sectional view of an apparatus for the photoexcitation process of the present invention.

In the figure, 101 is a thin square reaction container forming a reaction space A which is vacuum-sealed. Reference numeral 102 denotes a light-transmitting plate that constitutes a part of the upper wall of the thin rectangular reaction container 101, and an inverted truncated cone shape in which the inner surface of the light-transmitting plate and the inner surface of the upper wall of the thin rectangular reaction container 101 form the same plane. Has the shape of. A groove is provided in a notch on the upper wall of the vacuum reaction container into which the transparent plate 102 is fitted, and a ring-shaped packing 103 made of an elastic body is put therein for keeping airtightness. Reference numeral 104 is a wafer placed on the wafer table 105, and 106 is a wafer heating heater provided below the wafer table 105. 107 is a heat reflection plate installed so as to reflect the heat of the heater. Reference numeral 109 denotes a gas inlet provided on one side wall of the thin rectangular reaction vessel, a notch is provided on the lower wall immediately before the other side wall, and an exhaust pipe 110 for exhausting gas in the vacuum chamber is connected to the gas inlet. , Through a valve 111 to communicate with an exhaust device (not shown). 112 is a high energy generating means, 113 is an optical system such as a lens system, and 114 is high energy light.

The apparatus of the present invention is such that the inner wall of the thin rectangular reaction container is not uneven, and the shape of the gas inlet 109 provided on one side wall of the reaction container is a rectangular slit shape communicating with the thin rectangular reaction container. To do. The shape is set so that a step does not occur at the connection portion of the thin rectangular chamber.

By making the shape of the gas inlet and the shape of the inner wall of the thin square reaction container as described above, there is no sudden diffusion of the reaction gas into the reaction container as in the case of using a conventional nozzle, and the vicinity of the gas inlet is eliminated. The generation of vortices in the reactor is eliminated, and the reaction gas introduced into the reaction vessel is introduced into the gas inlet port 109.
Is supplied to the reaction space A in a laminar flow state.

That is, the gas streamlines are directed only in the horizontal direction above the wafer, and the velocity distribution in the vertical direction is the parabolic shape with the fastest central portion, and the velocity distribution in the horizontal direction is uniform, so It is possible to uniformly supply the reaction gas and reproduce the reaction gas supply state.

More preferably, the gas flow path is as shown in FIG.
Make an arc upward with a gentle slope,
The flow velocity of the reaction gas in the reaction space A is gradually decreased so that a sufficient photochemical reaction can be caused.

Furthermore, in order to prevent turbulent flow of the reaction gas due to radiation and convection from the heater for heating provided inside the wafer stage, the bottom wall of the thin rectangular reaction container other than the place where the wafer stage is installed is It is desirable to cool by piping 108. By cooling the lower wall other than the place where the wafer stage is installed, the effect of not causing a photochemical reaction on the inner wall other than the wafer can be achieved. Therefore, it is particularly preferable to provide such cooling means.

In the apparatus of the present invention, since the vacuum chamber is a thin rectangular chamber, the reaction space A formed above the wafer is narrowed, the gas phase reaction of the photochemical reactions is suppressed, and the surface reaction is promoted. When a deposited film is formed by the photo-CVD method using the above apparatus, there is also an effect that a dense thin film having a uniform film quality can be stably obtained.

In FIG. 1, in order to make the inner surface of the light-transmitting plate that allows high-energy light to pass through and the inner surface of the upper wall of the vacuum chamber to be flush with each other, the shape of the light-transmitting plate is an inverted truncated cone. As shown in FIG. 2, it is also possible to have a shape in which a step is provided around the disc-shaped light-transmitting plate 202 (so-called edge). In FIG. 2, 201 is an upper wall of the vacuum chamber, 202 is a translucent plate with an edge that fits into the cutout portion of the upper wall 201 of the vacuum chamber, and 203 is a ring-shaped ring made of an elastic body attached to maintain airtightness. It is packing.

Using the apparatus of the embodiment of the present invention shown in FIG. 1, for example, an amorphous silicon (hereinafter referred to as "a-Si") deposited film is formed on a wafer by the following process.

As the reaction gas, if an a-Si film is formed,
Specifically, it is possible to use a gas state such as silanes and halogenated silanes in which hydrogen, halogen, or hydrocarbon is bonded to silicon, or a gasified substance that can be easily gasified. These source gases are 1
One kind may be used, or two or more kinds may be used in combination. In addition, these raw material gases may be diluted with an inert gas such as He or Ar before use. Further, the a-Si film can be doped with a p-type impurity element or an n-type impurity element, and a raw material gas containing these impurity elements as a constituent is used alone or with the above-mentioned raw material gas or / And can be mixed with a diluting gas and introduced into the reaction space.

When two or more kinds of the raw material gases are used, it is possible to pre-excite one or more of the raw material gases to the excited species and then introduce the excited gas into the reaction chamber. .

First, the wafer stage installed in the thin square reaction container
In order to place the wafer 104 on the wafer 105, after removing the transparent plate 102, the wafer stage 105 is lifted by a driving device (not shown), and the thin square reaction container 101
Wafer stage 10 pushed up to the top of
Place the wafer on 5. After that, the wafer stage is lowered, and then the translucent plate is fitted into a predetermined position on the upper wall of the thin square reaction container, and attached by a bolt or the like.

Next, the inside of the thin rectangular reaction vessel 101 is evacuated using an exhaust device (not shown), and the pressure in the reaction vessel is set to 5 × 10 ⁻⁶ Torr or less, preferably 1 × 10 ⁻⁶ Torr.

Next, after premixing the reaction gas from each reaction gas supply source (not shown) to a predetermined composition ratio, the gas introduction port
It is introduced into the reaction space A from 109, and the pressure in the reaction space A is 1
× 10 ^{-2 to 1} Torr. Simultaneously with this, the high-energy light generating means 112 irradiates the high-energy light 114 condensed via the lens system 113 toward the reaction gas flowing in the laminar flow state in the reaction space A. . The reaction gas is excited and decomposed by irradiation with high-energy light to become an active species, and is heated to 50 to 450 ° C by a heater for heating, preferably on the wafer 104 heated and held at 200 to 300 ° C,
Form a deposited film. The undecomposed gas in the reaction gas introduced into the reaction space A and the active species not used for forming the deposited film flow in the reaction space A in a laminar flow state and are exhausted through the exhaust pipe 111. It

After the lapse of a predetermined time, the irradiation of high energy light, the introduction of the raw material gas, and the heating by the heating heater are stopped, the wafer is allowed to cool, and then the wafer is taken out in the reverse order of the above-mentioned case of placing the wafer.

In the above-mentioned example, a deposited film is formed by photo-CVD, but the device of the present invention can be used for photo-etching, photo-doping and the like in addition to the above example. When used for photoetching, a mask having a predetermined pattern is provided between the transparent plate 102 and the wafer 104, and photoetching is performed only in the portion where the high energy light 114 passes through the mask and reaches the wafer surface. Let it happen. When used for photodoping, an impurity gas is introduced and photodecomposed, and at the same time, the substrate is heated to diffuse the impurities into the substrate.

Further, in the case where the upper wall of the vacuum reaction vessel is not provided with the notch portion without disposing the light-transmitting plate 102, it can be used as an apparatus for dry process other than the photoexcitation process. By using an apparatus using a thin corner reaction container, a laminar flow of the introduced gas can be formed, and uniform gas supply to the wafer surface can be performed.

[Outline of Effects of Invention]

The apparatus for photoexcitation process of the present invention, the vacuum reaction vessel is a thin square reaction vessel, and eliminating the irregularities of the inner wall of the reaction vessel, the reaction gas by forming a rectangular slit-like gas communication port to the reaction vessel, Is to prevent a rapid change in the gas pressure and flow velocity of the reaction gas, and to form a stable laminar flow without wavy or vortex flow. It is possible to evenly supply and reproduce the reaction gas supply state. Furthermore, since the reaction space formed above the wafer is narrow in the apparatus of the present invention, it is possible to suppress the gas phase reaction and accelerate the surface reaction, and the film quality is uniform in the formation of the deposited film by photo-CVD. A stable and precise thin film can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an apparatus for photoexcitation process of the present invention, FIG. 2 is a schematic sectional view showing an example of mounting a transparent plate in the apparatus for photoexcitation process of the present invention, and FIG. 3 is conventional photoexcitation. 1 is a schematic sectional view showing an example of a processing apparatus.
In the figure, 101 ...... thin square reaction container, 201 ... upper wall of thin corner reaction container, 301 ... vacuum reaction container, 102,202,302 ... transparent plate, 10
3,203,303 …… Ring packing, 104,304 …… Wafer, 105,305 …… Wafer stage, 106,306 …… Heating heater, 107 …… Heat reflection plate, 108 …… Water cooling tube, 109 …… Gas inlet, 309 …… Gas supply Pipe, 110,310 ... Exhaust pipe, 11
1,311 …… Valve, 112,312 …… High energy generating means,
113,313 …… Optical system, 114,314 …… High energy luminous flux, A
...... Reaction space

Claims (5)

[Claims] 1. A high-energy light is supplied to a reaction gas through a vacuum reaction container forming a reaction space, a means for introducing a reaction gas into the vacuum reaction container, and a translucent plate arranged in the vacuum reaction container. In the apparatus for photoexcitation process including means for irradiating and means for evacuating the inside of the vacuum reaction container, the vacuum reaction container is a thin angle reaction container, and the inner surface of the thin angle reaction container and the inner surface of the transparent plate are In order to form a flat surface, and the inner surface of the thin square reaction container and the surface of the substrate mounted on the stage for mounting the substrate in the reaction space to form a flat surface, eliminating unevenness, An apparatus for a photoexcitation process, characterized in that the means for introducing the reaction gas is a rectangular gas inlet, and a step is eliminated at a joint between the gas inlet and the inner surface of the thin rectangular reaction container. 2. The photoexcitation process according to claim 1, wherein the translucent plate has an inverted truncated cone shape and is arranged so as to form a part of the upper wall of the thin rectangular reaction vessel. apparatus. 3. The method according to claim 1, wherein the translucent plate is a stepped disc, and the translucent plate is arranged so as to constitute a part of the upper wall of the thin rectangular reaction vessel. Apparatus for the described photoexcitation process. 4. The photoexcitation process apparatus according to claim 1, wherein the thin rectangular reaction vessel is shaped so as to form an arc upward. 5. The photoexcitation process apparatus according to claim 1, further comprising a cooling means corresponding to a lower wall of the thin rectangular reaction container other than the stage on which the stage is installed. .