JP3258121B2 - CVD equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD apparatus.

[0002]

2. Description of the Related Art In recent years, attention has been paid to an optical CVD method in which a material gas such as silane or diborane is decomposed by light energy to form a semiconductor thin film or the like by a chemical reaction. This is the conventional thermal CVD that decomposes the material gas using thermal energy.
This is because the optical CVD method has an advantage that a film can be formed at a lower temperature as compared with the method. Also, unlike the plasma CVD method, the reactive species contributing to the film formation are radicals, so that damage to the substrate by charged particles is suppressed as much as possible. Is formed.

[0003] In the photo-CVD method, generally, not all reaction products adhere to the substrate, but also adhere to the inner wall of the reaction chamber. When the film adhered to the inner wall of the reaction chamber is peeled off, dust is generated in the reaction chamber, and the yield decreases. Therefore, it is necessary to remove the film adhered to the inner wall of the reaction chamber. As a removing method, a decomposition cleaning method, a plasma discharge cleaning method, and the like have been proposed.

[0004] In the decomposition cleaning method, the reaction chamber is opened to the atmosphere, and the film adhered to the components is removed by a chemical or mechanical method. However, in this method, since the reaction chamber is exposed to the air, contaminants in the air are adsorbed on the inner wall of the reaction chamber. For this reason, a new evacuation process is required to remove contaminants, and there is a problem that throughput is reduced.

[0005] On the other hand, in the plasma discharge cleaning method, a plasma is generated by a cleaning electrode, and the adherend is removed by the plasma. The adherend can be removed without exposing it to the atmosphere.

FIGS. 16 to 18 show schematic constitutional views of a conventional optical CVD apparatus provided with a cleaning electrode. 16 shows a schematic configuration when viewed from the side, FIG. 17 shows a schematic configuration when viewed from above, and FIG. 18 shows a schematic configuration when viewed from the downstream side of the gas flow. ing.

In the drawing, reference numeral 1 denotes a reaction chamber, in which a stage 2 is installed, and a hot plate 4 having a built-in heater for mounting a substrate 3 is provided in the center thereof. Have been.

A material gas 6 is introduced into the reaction chamber 1 in a sheet form from a slit nozzle 5 provided on a side surface, and a mesh plate 8 and a quartz plate provided below a light introduction window 7 are provided. A purge gas 10, for example, an Ar gas, is introduced toward the lower part of the reaction chamber 1 through a flow guard plate 9 made of, and the material gas 6 forms a layer on the surface of the substrate 3 by forcibly pressing the material gas 6. It is designed to flow in a stream. These gases are exhausted to the outside by an exhaust pump 12 from an exhaust port 11 provided in a direction opposite to the slit nozzle 5.

Further, for cleaning the reaction chamber 1,
As shown in FIG. 17, just below the light introduction window 7 so as not to block the light incident path and to prevent gas introduced through the slit nozzle 5, the mesh plate 8 and the flow guard plate 9 from being obstructed. The cleaning electrode 13 is provided at a position outside of the shape and surrounding the stage 2. This cleaning electrode 13 is insulated from the wall of the reaction chamber 1 and furthermore, in order to prevent contamination by sputtering,
It is covered with quartz glass 14.

On the other hand, a lamp house 16 for accommodating a light source 15 such as a low-pressure mercury lamp for photo-CVD is provided at an upper portion of the reaction chamber 1, and a reflector 17 for reflecting light from the light source 15 is provided. Is attached to the rear of the light source 15. Then, the reaction chamber 1 and the lamp house 16
Is separated by a light introducing window 7 made of, for example, a synthetic quartz plate and a holder plate 18 for supporting the window. In the drawing, reference numeral 19 denotes a pipe for introducing and exhausting N ₂ as a purge gas into the lamp house 16.

Next, in the case of using the optical CVD apparatus configured as described above, for example, plasma cleaning of the reaction chamber 1 after forming an amorphous silicon film on the substrate 3 will be described below.

First, the substrate 3 is carried out of the reaction chamber 1.
Next, as the etching gas 21 from the slit nozzle 5,
A mixed gas of SF ₆ and O ₂ is introduced, and simultaneously, an Ar gas as a purge gas 10 is introduced into the reaction chamber 1 via the mesh plate 8 and the flow guard plate 9. Then, high-frequency power is applied to the cleaning electrode 13,
Generates plasma. The unnecessary amorphous silicon film deposited in the reaction chamber 1 is etched by the plasma. Here, the reason why the Ar gas 10 is introduced is to prevent the light introduction window 7 from being etched and fogged and the light transmittance from being reduced.

When observing the situation where the unnecessary amorphous silicon film is etched, first, the etching on the upstream side in the vicinity of the slit nozzle 5 is completed, and while this etching completed area gradually moves to the downstream side, It can be seen that the etching of the amorphous silicon film spreads.

That is, the speed up to the completion of the etching tends to be faster in the upstream region into which the etching gas is introduced, and to be slower in the downstream region. In particular, in the region further downstream than the region where the substrate 3 is placed, the tendency is higher. Is getting stronger.

According to the investigations by the present inventors, the time required for completing the etching is about 10 times as long in the downstream region as in the upstream region. This is because the etching gas SF ₆ is diluted on the downstream side by the Ar gas 10 introduced for preventing the light introduction window 7 from fogging, and the etching species such as atomic fluorine generated by the decomposition of SF ₆ by the discharge are: This is considered to be due to the reaction with SO ₂ on the downstream side to decrease.

As described above, the conventional cleaning electrode 13 is used.
In the photo-CVD apparatus provided with the above, the etching completion time of the downstream region becomes many times that of the upstream region, and the cleaning time of the reaction chamber 1 is determined by the etching completion time of the downstream region. That is, in the conventional photo-CVD apparatus that removes deposits by using plasma, there is a problem that a long time is required until the etching of the downstream region is completed, so that the cleaning time is extremely long and the throughput is reduced.

By the way, silane (SiH) is used as a material gas.
₄ ) In the photo-CVD method using a gas, since a material gas cannot be directly decomposed by ultraviolet light, a decomposition method utilizing the following chemical reaction, that is, a mercury sensitization method is often used. SiH ₄ + Hg ^* → SiH ₃ + H + Hg ^*

Here, Hg ^* The excitation mercury, · SiH ₃
Represents a SiH ₃ radical. Specifically, for example, SiH ₄ gas is introduced into the reaction chamber through a gas nozzle in a state of being mixed with mercury vapor through a mercury reservoir heated to about 90 ° C., and immediately after being introduced into the reaction chamber. , The SiH ₄ gas is decomposed into SiH ₃ radicals according to the above reaction formula.

Most of the SiH ₃ radicals are generated in a region near the slit nozzle 5 distant from the substrate 3 and reach the substrate 3 by diffusion or drift.
Some of the SiH ₃ radicals are
It is converted into a SiH ₂ radical by a secondary reaction shown below. SiH ₃ + SiH ₃ → SiH ₂ + SiH ₄ Here, SiH ₂ represents a SiH ₂ radical.

[0020] The SiH ₂ radicals, because of extremely high reactivity as compared with SiH ₃ radicals, SiH the substrate 3 ₂
When radicals fly, a film-forming reaction occurs with almost no migration. When the SiH ₂ radicals contribute to the film formation, the bonding state in the amorphous silicon film changes, and the quality deteriorates.

For this reason, for example, when an amorphous silicon film is formed on a 6-inch wafer, the gas nozzle side (upstream side) has a low quality of SiH ₂ radicals contributing to the film formation, and therefore has a high quality. A simple amorphous silicon film can be obtained.

However, on the opposite side (downstream side) of the gas nozzle, since a large amount of SiH ₂ radicals fly to the substrate 3, only a low-quality amorphous silicon film can be obtained. Therefore, a high-quality amorphous silicon film cannot be formed over a wide range of the wafer surface.

In a conventional optical CVD apparatus, light from a light source serving as a light energy supply source includes infrared light in addition to ultraviolet light which greatly contributes to film formation. As a result, the temperature rise of the substrate at the start of film formation becomes sharp due to the irradiation of infrared light. For this reason, there is a problem that the film quality in the film thickness direction becomes non-uniform due to a rapid temperature rise of the substrate.

[0024]

As described above, in the conventional photo-assisted CVD apparatus, it is necessary to remove the film adhered to the inner wall of the reaction chamber at the time of film formation in order to prevent a decrease in yield. Was. If the plasma discharge cleaning method is used,
Although the adherend can be removed without exposure to the air, there is a problem that the cleaning time becomes longer and the throughput is reduced due to restrictions on the arrangement of the discharge electrodes.

When SiH ₄ is used as a material gas for an amorphous silicon film in a conventional optical CVD apparatus, this SiH ₃ radical is downstream in addition to the SiH ₃ radical directly contributing to the deposition of the amorphous silicon film. Si, which causes deterioration of the film quality as it is transported to the
Since H ₂ radicals is increased, over a wide range of the wafer surface, there is a problem that it is impossible to form a high quality amorphous silicon film.

Furthermore, in the conventional optical CVD apparatus, the light from the light source includes infrared light in addition to ultraviolet light which greatly contributes to film formation.
There has been a problem that the substrate is rapidly heated at the start of film formation, and the film quality in the film thickness direction becomes non-uniform.

The present invention has been made in view of the above circumstances, and a problem to be solved is to provide a CVD apparatus capable of preventing non-uniformity of film quality and a decrease in throughput.

[0028]

In order to solve the above problems BRIEF SUMMARY OF THE INVENTION, CVD apparatus according to the present invention (Claim 1) includes a reaction chamber for forming a film accommodating the substrate, into the reaction chamber A gas nozzle for supplying a material gas for film formation, a light irradiating unit for irradiating the material gas introduced into the reaction chamber with light, and an etching gas for removing an adherend in the reaction chamber Provided with a gas nozzle for discharging and a discharge electrode for removing an adherend provided in the reaction chamber
In the apparatus, the gas nozzle that supplies the etching gas is a first gas nozzle that is used in common with the gas nozzle that supplies the material gas, and a second gas nozzle that is provided downstream of the gas supplied from the first gas nozzle. And a gas nozzle.

Further, another CVD apparatus according to the present invention (claim 2) is a reaction chamber for accommodating a substrate and performing film formation, and a material gas for film formation or a substance for removing an adherend in the reaction chamber. A gas nozzle for supplying an etching gas, a light irradiating means for irradiating the material gas introduced into the reaction chamber with light, and a discharge electrode for removing an adherend provided in the reaction chamber. The apparatus is characterized in that the gas nozzle is movable in a downstream direction of the etching gas.

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

According to the CVD apparatus of the present invention, the second gas nozzle is provided downstream of the etching gas supplied from the first gas nozzle commonly used for supplying the material gas. By the etching gas supplied from the second gas nozzle, the etching species sufficiently spread to the downstream side.

Therefore, as compared with the conventional CVD apparatus,
Since the etching rate on the downstream side is increased, the cleaning time in the reaction chamber is greatly reduced, and the throughput can be improved.

Further, according to another CVD apparatus of the present invention, the gas nozzle is movable in the downstream direction of the etching gas, so that the etching completion area advances downstream. By moving the gas nozzle in the downstream direction, the etching species is sufficiently supplied to the downstream region.

Therefore, as compared with the conventional CVD apparatus,
Since the etching rate on the downstream side is increased, the cleaning time in the reaction chamber is greatly reduced, and the throughput can be improved.

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

Embodiments will be described below with reference to the drawings.

FIG. 1 shows an optical CVD according to an embodiment of the present invention.
It is a schematic structure figure of an apparatus. FIG. 1A shows a schematic configuration when viewed from the side, and FIG. 1B shows a schematic configuration when viewed from above.

In the drawing, reference numeral 101 denotes a reaction chamber, in which a stage 102 is installed, and a hot plate 104 containing a heater 106 for mounting a substrate 103 is provided in the center thereof. Is provided.

The reaction chamber 101 is shown in FIGS.
8 is provided with a slit nozzle 105a (first gas nozzle) similar to that of the conventional optical CVD apparatus shown in FIG. 8, and further, a downstream position of the gas supplied from the slit nozzle 105a into the reaction chamber 101, that is, a hot nozzle. An unconventional slit nozzle 105b (second gas nozzle) is provided on the stage 2 downstream of the plate 104.

In the figure, reference numeral 110 denotes a purge gas (for example, Ar gas).
Is a flow guard plate 1 made of a mesh plate 108 and a quartz plate provided below the light introduction window 107.
09 to the lower part of the reaction chamber 101. The material gas 122 is pressed against the surface of the substrate 103 by the purge gas 110 introduced as described above, and these gases 110 and 122 are provided on the opposite side of the slit nozzle 105 a by the exhaust pump 112, Exhausted.

In order to clean the reaction chamber 101, the light incident path is not blocked and the slit nozzle 105
a, 105b, and a cleaning electrode 113 surrounding the stage 102 at a position outside and just below the light introduction window 107 so as not to hinder the gas introduced through the mesh plate 108 and the flow guard plate 109. (Discharge electrodes for removing adherends) are provided. The cleaning electrode 113 is connected to the reaction chamber 1.
In addition, the surface is covered with a protective film 114 (for example, quartz glass) to be insulated from the inner wall of the substrate 01 and prevent contamination by sputtering. Further, the light introduction window 1
As 07, for example, a synthetic quartz plate is used.

On the other hand, in the upper part of the reaction chamber 101, for example,
A lamp house 116 that accommodates a light source 115 composed of a low-pressure mercury lamp is provided, and a reflector 117 is attached to the rear thereof. The reaction chamber 101 and the lamp house 116 are partitioned by the light introducing window 107 and a holder plate 118 for supporting the window. In the drawing, reference numeral 119 denotes a pipe for introducing and exhausting N ₂ as a purge gas into the lamp house 116.

For example, when an amorphous silicon film is formed by the optical CVD apparatus having the above-described structure, the substrate 103 is placed on a hot plate 104 and heated in a mesh plate as in the conventional case. A purge gas 110 is introduced below the reaction chamber 1 through the flow guard plate 109 and the material gas 12 introduced in a sheet form from the slit nozzle 105a.
2. For example, a SiH ₄ gas mixed with mercury vapor is pressed down and flows on the substrate 103 in a laminar flow. Then, light from the light source 115 is irradiated onto the substrate 103 from above, whereby an amorphous silicon film is formed on the surface of the substrate 103.

On the other hand, when cleaning the inside of the reaction chamber 101, first, the substrate 103 is taken out of the reaction chamber 101, and then an inert purge gas 110 is supplied to the lower part of the reaction chamber 101 through the mesh plate 108 and the flow guard plate 109. While introducing the etching gas 1
In step 21, for example, an SF ₆ / O ₂ mixed gas is introduced from both the slit nozzle 105a and the slit nozzle 105b. Here, S from the slit nozzle 105b
F ₆ gas alone may be used.

In this state, the cleaning electrode 1 is
A high frequency power is applied to 13 to generate plasma discharge, whereby the etching gas 121 is decomposed, and thereby an unnecessary deposited film in the reaction chamber 101 formed at the time of film formation is removed by etching. At this time, since the lower part of the light introduction window 107 is covered with the inert purge gas 110,
The light transmission window 107 is not etched and the light transmittance is not reduced.

According to the photo-assisted CVD apparatus of this embodiment, the gas nozzle 105a commonly used for supplying the material gas 122 is used.
The independent gas nozzle 105b is provided downstream of the etching gas (SF ₆ ) supplied from the nozzle. Therefore, by the etching gas 121 supplied from the independent gas nozzle 105b, the etching species (F radical and atomic Condition F) is fully distributed.

As a result, the etching speed in the downstream region is improved, and the etching speed in the reaction chamber 101 is made uniform.
21 is diluted or the number of etching species is reduced, so that the etching speed in the downstream region is greatly reduced.
The disadvantage of the D device can be eliminated.

Therefore, as compared with the conventional CVD apparatus,
The cleaning time in the reaction chamber 101 is greatly reduced,
Throughput can be improved. The installation location of the slit nozzle 105b provided on the stage 102 is not limited to the stage 2 on the downstream side of the hot plate 4;
Any shape downstream of the hot plate 4 may be used.

FIG. 2 shows an optical CV according to another embodiment of the present invention.
It is a schematic structure figure of D apparatus. 2A shows a schematic configuration when viewed from above, and FIG. 2B shows a schematic configuration when viewed from the side. In the following figures, parts corresponding to those described above are given the same reference numerals as in FIG.
Detailed description is omitted.

The difference between the photo-assisted CVD apparatus of this embodiment and the previous embodiment is that the etching gas 121 and the material gas 122 are used.
Two gas nozzles 105c and 105d independent of the gas nozzle 105a commonly used for the introduction of the gas are provided on two side surfaces perpendicular to the side surface of the reaction chamber 101 in which the gas nozzle 105a is provided. is there.

In order to form a film using the photo-assisted CVD apparatus configured as described above, the material gas 122 is supplied from the slit nozzle 105a to the reaction chamber 101 in the same manner as in the previous embodiment.
And introduces a sheet-like material gas 122 into the substrate 103.
Pour over

On the other hand, when cleaning the reaction chamber 101, a purge gas 110 such as Ar is introduced below the reaction chamber 101 through the mesh plate 108 and the flow guard plate 109, and the etching gas 12 is removed.
1. For example, to remove an amorphous silicon film, use S
The F ₆ / O ₂ mixed gas is supplied to the slit nozzles 105a, 105
c and 105d are introduced into the reaction chamber 101. As in the previous embodiment, only SF ₆ gas may be supplied from the slit nozzles 105c and 105d. Then, in this state, high-frequency power is applied to the cleaning electrode 113 to generate plasma discharge, thereby decomposing the etching gas 121, thereby etching and removing an unnecessary film in the reaction chamber 101.

In the optical CVD apparatus of this embodiment, in addition to the gas nozzle 105a commonly used for introducing the material gas 121 and the etching gas 122, the gas nozzles 105c provided on both side surfaces downstream of the gas nozzle 105a are also provided. The etching gas 121 is also introduced from 105d.

For this reason, the etching gas 12
Since 1 is not diluted or the number of etching species is not reduced, the etching rate in the downstream region is improved as in the previous embodiment, and the etching rate in the reaction chamber 101 is made substantially uniform. Therefore, the cleaning time in the reaction chamber 101 can be significantly reduced, and the throughput can be improved.

FIGS. 3 to 5 are schematic structural views of an optical CVD apparatus according to another embodiment of the present invention. 3 shows a schematic configuration diagram (at the time of film formation) when viewed from the side, FIG. 4 also shows a schematic configuration diagram (at the time of etching) when viewed from the side, and FIG. 5 shows a front view from the downstream side of the gas flow. FIG. 3 shows a schematic configuration diagram (at the time of etching) when viewed.

In the figure, reference numeral 201 denotes a reaction chamber, in which a stage 202 is installed, and a hot plate 204 having a built-in heater 223 for mounting a substrate 203 is provided in the center thereof. Is provided. A slit nozzle 205 (gas nozzle) for introducing a gas is provided in the reaction chamber 201 at the same side position as the conventional photo-CVD apparatus shown in FIGS.

Here, the point that the photo-assisted CVD apparatus of this embodiment is different from the conventional one is that
As shown in FIG. 18, the slit nozzle 5 is fixed, whereas the slit nozzle 2 of this embodiment is fixed.
05 is the nozzle holder 205a and the slit nozzle body 2
05b, and the slit nozzle body 205
b can protrude forward (downstream of the gas flow) as needed from the conventional nozzle tip position.

The cleaning electrode 213 is arranged so as not to come into contact when the slit nozzle body 205b projects forward. The other parts are the same as those of the above-described conventional photo-CVD apparatus, and therefore detailed description thereof will be omitted here. In addition,
In the figure, reference numeral 218 denotes a holder plate, and 219 denotes a pipe for introducing and exhausting N ₂ as a purge gas into the lamp house 216. Next, the formation of an amorphous silicon film using the optical CVD apparatus configured as described above will be described.

First, as shown in FIG. 3, the slit nozzle body 205b is housed in the nozzle holder 205a (a state in which the slit nozzle body 205b does not protrude), and is placed on the hot plate 204 in this state. The heated substrate 203 is heated to a predetermined temperature.

Next, when the temperature of the substrate 203 is stabilized, the mesh plate 208 and the flow guard plate 20
9, a purge gas 210 (for example, Ar) is introduced below the reaction chamber 201, and the purge gas 210 causes the sheet-like material gas 222 to be an amorphous silicon film introduced into the reaction chamber 201 from the slit nozzle 205. (E.g., SiH ₄ gas mixed with mercury vapor), and a laminar material gas 206
Flow.

By irradiating the substrate 203 with light from a light source 215 provided above the reaction chamber 201, an amorphous silicon film is formed on the surface of the substrate 203. At this time, since the film formation does not proceed in the light incident window 207 due to the purge gas 210, a high-quality amorphous silicon film is formed on the substrate 203 at a constant film formation rate.

On the other hand, when cleaning the reaction chamber 203, first, the substrate 203 is taken out of the reaction chamber 201, and thereafter, the purge gas 210 is moved below the reaction chamber 201 through the mesh plate 208 and the flow guard plate 209. While introducing the etching gas 221
(For example, SF ₆ / O ₂ mixed gas) into slit nozzle 2
Introduce from 05.

Then, in this state, the cleaning electrode 2
By applying a high-frequency power to 13 to generate a plasma discharge, the etching gas 221 is decomposed, and thereby an unnecessary film in the reaction chamber 201 is removed by etching.

In this etching, at the start of the etching, as shown in FIG.
A state in which the slit nozzle body 205b is housed in 05a (a state in which the slit nozzle body 205b does not protrude)
Keep it.

Thereafter, as the etching progresses, the etching completed region gradually expands from the upstream side to the downstream side.
As shown in FIGS. 4 and 5, the etching is performed while protruding in the downstream direction as shown in FIGS. 4 and 5, so that the etching species are sufficiently supplied to the downstream region.

In this regard, SF was used as an etching gas.
To be more specific, an example in which a ₆ / O ₂ mixed gas is used will be described. In a conventional optical CVD apparatus, since a slit nozzle is fixed, S is provided on the downstream side by a purge gas.
Since the F ₆ gas is diluted and the atomic F generated by the discharge decomposition of the SF ₆ gas reacts with SO ₂ on the downstream side to decrease, the etching rate in the downstream region is greatly reduced.

On the other hand, according to the photo-CVD apparatus of this embodiment,
Since the etching proceeds and the slit nozzle main body 205b extends in the downstream direction as the etching completion area progresses to the downstream side, the atomic F as an etching species is sufficiently supplied to the downstream area. The etching rate on the downstream side is greatly accelerated. Therefore, the reaction chamber 2
01, the cleaning time is greatly reduced, and the throughput can be improved.

Thus, according to this embodiment, in the so-called plasma cleaning, in which unnecessary films deposited in the reaction chamber are removed by plasma, so-called plasma cleaning, the use of a slit nozzle which can move in the direction in which the etching completed region is advanced is slow. The etching rate on the downstream side is greatly accelerated, and the cleaning time is greatly shortened. As a result, the throughput can be greatly improved.
In addition, since the lower portion of the light introduction window is covered with an inert purge gas during etching, the light introduction window is not etched and the light transmittance does not decrease. Therefore, film formation and cleaning can be continuously performed. FIG. 6 and FIG.
FIG. 7 is a schematic configuration diagram of a photo-CVD apparatus according to another embodiment of the present invention.

The difference between the photo-assisted CVD apparatus of FIG. 6 and that of the previous embodiment is that a pair of electrodes 213 a surrounding both sides of the stage 202 are used as the cleaning electrodes 213. The difference between the photo-assisted CVD apparatus of FIG. 7 and that of the embodiment of FIG. 6 is that an electrode 213b is bridged as a cleaning electrode 213 at a downstream portion to a pair of electrodes 213a in a direction perpendicular thereto. is there.

The cleaning electrodes of the above two photo-CVD devices do not block the light incident path and do not hinder the gas flow introduced from the slit nozzle 205, as in the case of the previous embodiment. The slit nozzle 205 is installed at an outside position just below the light introduction window 207.
Even if it protrudes, it does not come into contact. These cleaning electrodes 213 are insulated from the inner wall of the reaction chamber 201 and covered with a protective film 214 made of, for example, quartz glass in order to prevent the electrodes from being sputtered, as in the conventional case. ing.

In the optical CVD apparatus configured as described above,
As the slit nozzle body 205b protrudes in the downstream direction as the etching completion area progresses to the downstream side, the etching species is sufficiently supplied to the downstream area, so that the throughput can be improved. Note that the structure of the cleaning electrode 213 is not limited to the above-mentioned three, and variously modified ones can be used.

FIG. 8 is a schematic configuration diagram of a laminar flow type photo CVD apparatus using a mercury sensitization method according to a reference example of the present invention .
(A) shows a schematic configuration diagram when viewed from above, and FIG.
(B) shows a schematic configuration diagram when viewed from the side.

In the drawing, reference numeral 305 denotes a reaction chamber, in which a substrate 306 is accommodated. The substrate 306 is heated by a substrate heating heater 307 incorporated in the reaction chamber bottom 321. The substrate heating heater 307 is controlled by the first temperature control device 327. That is, the temperature of the substrate 306 is controlled by the substrate heating heater 307 and the first temperature control device 327. Also, the reaction chamber 30
5, a lamp house 301 is provided. In the lamp house 301, a light source 302 including a low-pressure mercury lamp is provided. In addition, N ₂ is introduced as a purge gas into the lamp house 301, thereby preventing the attenuation of ultraviolet light due to light absorption of atmospheric components (oxygen gas, water vapor, etc.).

[0086] Above the light source 302, a reflection plate 303 is arranged. The light emitted from the light source 302 is directly applied to the substrate 306 via the light introduction window 304 made of quartz or the like, or is reflected by the reflection plate 303 and is reflected by the light introduction window 3.
Irradiation is performed on the substrate 306 through the substrate 04.

On the other hand, below the light source 302, a gas flow control plate 312 made of a material that transmits ultraviolet light, for example, quartz.
Is provided. A mesh nozzle 311 transparent to ultraviolet light is provided between the gas flow control plate 312 and the light introduction window 304.

Further, outside the reaction chamber 305, a mercury reservoir 309 in which mercury 300 maintained at a constant temperature is stored.
A material gas supply unit (not shown) containing a material gas such as SiH ₄ , a purge gas supply unit (not shown) containing an inert substance such as Ar as a purge gas, and an exhaust port 313 from the reaction chamber. A gas exhaust unit (not shown) including a vacuum exhaust pump 308 for exhausting the gas in 305 is provided. Here, a mechanism for mixing a substance having an absorptivity to ultraviolet light into the purge gas may be provided.

Material gas 3 supplied from the material gas supply unit
32 is introduced into the reaction chamber 305 via a mercury reservoir 309 and a material / etching gas introduction nozzle 310a (gas nozzle). That is, a mixed gas of the material gas 32 and the mercury vapor flows in the reaction chamber 305.

The purge gas 334 supplied from the purge gas supply unit is supplied to the substrate 306 via the purge gas introduction nozzle 310b, the mesh nozzle 311 and the gas flow control plate 312.
Sprayed on. As a result, a mixed gas of the material gas 332 and the mercury vapor flows in parallel with the substrate 306, and
A laminar flow of the mixed gas is formed in the vicinity of the surface, and a laminar flow of the purge gas 334 is formed in other portions.

In addition to such a basic structure, the photo-assisted CVD apparatus according to the present embodiment includes a substrate surrounding heating heater 322 for heating the reaction chamber bottom 321 other than where the substrate 306 is mounted. A second temperature control device 328 for controlling the substrate surrounding heater 322;
And a cooling water pipe 323 for circulating cooling water 333 for cooling the reaction chamber bottom 321 in a portion other than the portion where the water is placed.

Further, the first temperature control device 327, the second temperature control device 328, the refrigerant introduction valve 326 provided in the cooling water pipe 323, the etching gas 331
A main control device 329 for controlling an etching gas introduction valve 325 provided on the pipe for introducing the material gas and a material gas introduction valve 324 provided on the pipe for introducing the material gas 332 is provided.

The main controller 329 includes a material gas introduction valve 324 and an etching gas introduction valve 325.
As shown in Table 1, the first temperature control device 327 and the second temperature control device 327 are independent from each other so that the substrate heating heater 307 and the substrate surrounding heating heater 322 are turned on or off in response to the opening and closing of The controller 328 is controlled.

[0093]

[Table 1] Next, a method for forming an amorphous silicon film using the optical CVD apparatus configured as described above will be described.

First, the material gas introduction valve 324 is opened, and the SiH ₄ gas as the material gas 332 mixed with the mercury vapor is introduced into the reaction chamber 305 in the mercury reservoir 309 via the material / etching gas introduction nozzle 310a. A laminar gas flow is formed near the substrate 306.

At this time, main controller 329 controls first temperature controller 327 such that the temperature of substrate heating heater 307 becomes 230 ° C. Further, the main controller 32
9 controls the second temperature control device 328 so that the substrate surrounding heater 321 is turned off, sets the refrigerant introduction valve 327 to a closed state, and supplies the cooling water 333 to the cooling water pipe 323. Shed. That is, the substrate 306
Is heated so that the reaction chamber bottom 321 around it is cooled.

Here, mercury vapor is excited by the light from the light source 303, and the excited mercury decomposes the SiH ₄ gas, thereby generating SiH ₃ radicals, which are film-forming species. Then, the SiH ₃ radical is transferred to the substrate 30.
6 and an amorphous silicon film is formed.

In the formation of this silicon thin film, the deposition rate depends on the surface reaction rate, and shows a so-called activation type substrate surface temperature dependency. FIG. 9 is a characteristic diagram showing the relationship between the substrate temperature and the deposition temperature. From FIG. 9, it can be seen that the deposition rate monotonically increases with the substrate temperature.

Therefore, by heating the substrate 306 and cooling the reaction chamber bottom 321 around the substrate 306 as described above, the deposition rate of the reaction chamber bottom 321 around the substrate 306 can be suppressed. The value is about 1/3 of the conventional structure
It was confirmed that it was about. Therefore, according to the present embodiment , the amount of deposits (unnecessary deposits) deposited on portions other than the substrate during film formation can be significantly reduced. On the other hand, the method of removing the amorphous silicon film deposited inside the reaction chamber 305 during the film formation is performed according to the following procedure.

First, the substrate 306 is carried out of the reaction chamber 305. Next, the etching gas introduction valve 325 is opened, and SF ₆ gas, for example, is introduced into the reaction chamber 305 as the etching gas 331 at a flow rate of 100 SCCM. At the same time, for example, Ar gas is used as an inert purge gas for preventing the light introduction window 304 from being etched at a flow rate of 4.5 SLM and the purge gas nozzle 310 is used.
b. The pressure inside the reaction chamber 305 is reduced to about 0.5 Torr by the vacuum pump 308.

Here, the main controller 329 controls the first and second temperature controls 327 and 328 so that the temperatures of the substrate heating heater 307 and the substrate surrounding heater 321 become 230 ° C. together. Then, the refrigerant introduction valve 327 is set to the open state. That is, the substrate 306
And the surroundings of the reaction chamber bottom 321 are heated accordingly.

Then, RF power of, for example, 200 W is applied by the high-frequency power source 315 to the cleaning electrode 314.
Give to. As a result, a plasma discharge region is formed between the cleaning electrode 314 and the inner wall of the reaction chamber 305,
The SF ₆ gas as the etching gas 331 is decomposed, and atomic F as an etching species is generated. This atomic F
As a result, the hydrogenated amorphous silicon film deposited inside the reaction chamber 305 is removed by etching.

Also in this etching step, the etching rate depends on the surface reaction rate, and shows a so-called activation type substrate surface temperature dependency. As shown in FIG.
The etching rate increases as the substrate temperature increases.

Therefore, by heating the substrate 306 and the reaction chamber bottom 321 around the substrate 306 to the same high temperature as described above, the etching rate becomes about 1.5 times the conventional value.
It was confirmed that it became double.

Therefore, the reaction chamber 305 during film formation
The conventional light CV is reduced by reducing the amount of hydrogenated amorphous silicon film deposited on the inside and increasing the etching rate.
The cleaning time of the reaction chamber 305 is greatly reduced as compared with the D apparatus, and the throughput can be greatly improved.

As described above, according to the present embodiment , the temperature of the substrate 306 and the temperature of the reaction chamber bottom 321 around the substrate 306 can be controlled independently. Since the generation of a film to be deposited can be suppressed and the etching rate at the time of cleaning can be improved, the time required for the cleaning process can be greatly reduced, and the throughput can be greatly improved.

[0106] In the present embodiment, the description has been given of the laminar flow type optical CVD apparatus using a mercury sensitization method, application
Approach is the direct excitation type which does not use mercury sensitization reaction light CV
The present invention can also be applied to a CVD apparatus such as a D method or a plasma CVD method.

Further, in this embodiment , the CVD apparatus having a configuration in which only the bottom of the reaction chamber around the substrate is heated and cooled has been described. However, not only the bottom of the reaction chamber but also other parts can be similarly heated and cooled. It is good. Since the control range of the reaction speed is wider in the CVD apparatus having such a configuration, the effect is also increased.

Further, in this embodiment , the heater and the cooling water are used to heat and cool the bottom of the reaction chamber around the substrate, but the current control is performed by using the Peltier element utilizing the thermoelectric effect. Heating and cooling can be performed only by heating. By using such a Peltier element, the control mechanism can be simplified.

FIG. 11 is a schematic configuration diagram of a laminar flow type photo-CVD apparatus using a mercury sensitization method according to another reference example of the present application , and FIG. 11 (a) is a schematic configuration diagram when viewed from above. FIG. 11B shows a schematic configuration diagram when viewed from the side. The difference between the photo-assisted CVD apparatus of this embodiment and that of the above-described embodiment is that the bottom of the reaction chamber around the substrate is heated and cooled by a heat medium.

In the drawing, reference numeral 405 denotes a reaction chamber, in which a substrate 406 is accommodated. The substrate 406 is heated by a substrate heating heater 407 incorporated in the bottom 431 of the reaction chamber. Further, a lamp house 401 is provided above the reaction chamber 405, and inside the lamp house 401,
A light source 402 including a low-pressure mercury lamp is provided.
Further, N ₂ is used as a purge gas in the lamp house 401.
Has been introduced, which allows atmospheric components (oxygen gas,
UV light is prevented from attenuating due to light absorption of water vapor or the like.

A reflecting plate 403 is arranged above the light source 402. The light emitted from the light source 402 is directly applied to the substrate 406 through a light introduction window 404 made of quartz or the like, or is reflected by a reflection plate 403 and is reflected by the light introduction window 4.
The substrate 406 is irradiated through the substrate 04.

On the other hand, below the light source 402, a gas flow control plate 412 made of a material that transmits ultraviolet light, for example, quartz.
Is provided. A mesh nozzle 411 transparent to ultraviolet light is provided between the gas flow control plate 412 and the light introduction window 404.

Outside the reaction chamber 405, a mercury reservoir 409 in which mercury 400 maintained at a constant temperature is stored,
a material gas supply unit (not shown) containing a material gas such as iH ₄ , a purge gas supply unit (not shown) containing an inert substance such as Ar as a purge gas, and a reaction chamber 405.
A gas exhaust unit (not shown) including a vacuum exhaust pump 408 for exhausting gas from the inside through an exhaust port 413 is provided. Note that a mechanism for mixing a substance exhibiting absorptivity to ultraviolet light into the purge gas may be provided.

The material gas 4 supplied from the material gas supply unit
Numeral 22 is introduced into the reaction chamber 405 via a mercury reservoir 409 and a material / etching gas introduction nozzle 410a. That is, the mixed gas of the material gas 42 and the mercury vapor is supplied to the reaction chamber 4.
It flows inside 05.

The purge gas 434 supplied from the purge gas supply unit is blown onto the substrate 406 via the purge gas introduction nozzle 410b, the mesh nose 411, and the gas flow control plate 412. As a result, a mixed gas of the material gas 422 and the mercury vapor flows in parallel with the substrate 406, and a laminar flow of the mixed gas is formed near the surface of the substrate 406, and a laminar flow of the purge gas 434 is formed in other portions. Is done.

In addition to such a basic structure, the optical CVD apparatus of the present embodiment has a heating medium circulating system for heating or cooling the reaction chamber bottom 421 at a portion other than where the substrate 406 is mounted. Pipe 433 and low-temperature heat medium circulating device 4
42, a high-temperature heat medium circulation device 443, and a valve opening / closing control device 441. As the heat medium, for example, perfluoropolyether is used.

The valve opening / closing control device 441 includes valves 444 a, 444 inserted in the heat medium circulating pipe 433.
b, 445a and 445b, and an etching gas introduction valve 425 and a material gas 422 for introducing an etching gas 421 into the reaction chamber 405.
Of the material gas introduction valve 424 for introducing the gas into the reaction chamber 405 is controlled.

The valve opening / closing control device 441 corresponds to the opening / closing of the material gas introduction valve 424 and the etching gas introduction valve 425, and the valves 444a and 444b inserted in the heat medium circulation pipe 433 as follows. , 44
Control of opening and closing of 5a and 445b is performed.

That is, the material gas introduction valve 424 and the etching gas introduction valve 425 are respectively
In the open state and the closed state, that is, at the time of film formation, the valves 444a and 444b are opened and the valve 445a is opened.
And 445b are closed. On the other hand, a material gas introduction valve 324 and an etching gas introduction valve 325
Are closed and open, that is, during etching, the valves 444a and 444b are closed and the valves 445a and 445b are open. Next, a method for forming an amorphous silicon film using the optical CVD apparatus configured as described above will be described.

First, the material gas introduction valve 424 is opened, the etching gas introduction valve 425 is closed, and in the mercury reservoir 409, the material / etching gas introduction nozzle 410a is supplied with the SiH ₄ gas as the material gas 432 mixed with the mercury vapor. Through the reaction chamber 405 to form a laminar gas flow near the substrate 406.

At this time, the valves 444a and 444b are opened and the valves 445a and 445b are closed by the valve opening / closing control device 441.
And a low-temperature heat medium circulating device 44
The heat medium cooled to 15 ° C. in Step 2 is circulated. The substrate 406 is heated to 230 ° C. by the substrate heater 407.

Here, mercury vapor is excited by the light from the light source 402, and the excited mercury decomposes the SiH ₄ gas, thereby generating SiH ₃ radicals as film-forming species. Then, the SiH ₃ radical is transferred to the substrate 40.
6 and an amorphous silicon film is formed.

In the formation of this silicon thin film, the deposition rate depends on the surface reaction rate as in the case of the above-mentioned reference example, and therefore, as shown in FIG. It can be seen that the value increases monotonically with.

Thus, by heating the substrate 406 as described above and cooling the reaction chamber bottom 341 around the substrate 406, the deposition rate of the reaction chamber bottom 321 around the substrate 406 can be suppressed. The value is about 1/5 of the conventional structure
It was confirmed that it was about. Therefore, according to the present embodiment , the amount of deposits (unnecessary deposits) deposited on portions other than the substrate during film formation can be significantly reduced. On the other hand, the method of removing the amorphous silicon film deposited inside the reaction chamber 405 during the film formation is performed in the following procedure.

First, the substrate 406 is carried out of the reaction chamber 405. Next, the valve 425 for introducing the etching gas is opened, the valve 424 for introducing the material gas is closed, and the reaction chamber 40 is closed.
For example, SF ₆ gas is introduced as an etching gas 421 in the flow rate 5 at a flow rate of 100 SCCM. At the same time, for example, Ar gas is used as an inert purge gas for preventing etching of the light introduction window 404 at a flow rate of 4.5 S.
It is introduced from the purge gas nozzle 410b under the condition of LM. Further, the inside of the reaction chamber 405 is
8, the pressure is reduced to about 0.5 Torr.

Then, the RF power of, for example, 200 W is supplied by the high-frequency power supply 415 to the cleaning electrode 414.
Give to. As a result, a plasma discharge region is formed between the cleaning electrode 414 and the inner wall of the reaction chamber 405,
The SF ₆ gas as the etching gas 421 is decomposed, and atomic F as an etching species is generated. This atomic F
As a result, the hydrogenated amorphous silicon film deposited inside the reaction chamber 405 is removed by etching.

At this time, the valves 444a and 444b are closed by the valve opening / closing control device 441,
45a and 445b are opened, and the bottom of the reaction chamber 431 around the substrate 406 is cooled by a high-temperature heat transfer medium circulating device 443.
The heating medium heated to 0 ° C. circulates. The substrate 406 is heated to 230 ° C. by the substrate heater 407.

[0128] In this etching process, the previous reference
As in the example , the etching rate depends on the surface reaction rate,
As shown in FIG. 9 described above, the etching rate increases as the substrate temperature increases.

For this reason, it was confirmed that by heating the substrate 406 and the reaction chamber bottom 431 around the substrate 406 to a high temperature as described above, the etching rate was increased to about 1.5 times the conventional rate.

Therefore, the reaction chamber 405 during film formation
The conventional light CV is reduced by reducing the amount of hydrogenated amorphous silicon film deposited on the inside and increasing the etching rate.
The cleaning time of the reaction chamber 405 is greatly reduced as compared with the D apparatus, and the throughput can be greatly improved.

[0131] As described above, the previous reference, even this reference example
As in the example , since the temperature of the substrate 406 and the temperature of the reaction chamber bottom 431 around the substrate 406 can be controlled independently, the film adhered to the reaction chamber bottom 431 around the substrate during film formation can be suppressed, and the time of cleaning can be reduced. Since the etching rate can be improved, the time required for the cleaning process can be significantly reduced, and the throughput can be significantly improved.

[0132] In the present embodiment, the description has been given of the laminar flow type optical CVD apparatus using a mercury sensitization method, application
Approach is the direct excitation type which does not use mercury sensitization reaction light CV
The present invention can also be applied to a CVD apparatus such as a D method or a plasma CVD method.

Further, in this embodiment , the CVD apparatus having a configuration in which only the bottom of the reaction chamber around the substrate is heated or cooled has been described. However, not only the bottom of the reaction chamber but also other parts are similarly heated or cooled by the heating medium. It is good also as a structure which can be cooled. Since the control range of the reaction speed is wider in the CVD apparatus having such a configuration, the effect is also increased.

FIGS. 12 and 13 are schematic structural views of a laminar flow type photo-CVD apparatus using a mercury sensitization method according to another reference example of the present invention, and show a state before the start of film formation and a state at the time of film formation, respectively. It shows.

The optical CVD apparatus of the present embodiment is different from the conventional apparatus in that a substrate heating device 511 (heating means) composed of an infrared ray generator for heating a substrate 506 is incorporated in the optical circuit breaker 503. is there. In addition, the optical circuit breaker 5
03 is provided with a reflection plate 513 that reflects infrared light, so that the substrate 506 can be efficiently heated by the substrate heating device 511.

Before the start of film formation, as shown in FIG. 12, a light interrupter 5 is provided so that light from a low-pressure mercury lamp 502 provided in a lamp house 501 is not irradiated on the substrate 506.
03 is located below the low-pressure mercury lamp 502. The inside of the lamp house 501 is purged with a gas that does not absorb ultraviolet light, for example, N2 gas.

Further, in the case of this reference example , unlike the prior art,
Before film formation, the substrate 5
06 is heated to, for example, about 250 ° C. Also,
A cooling device 512 is provided in the light interrupter 503, and the cooling device 512 is provided by the substrate heating device 511.
03 itself is prevented from rising.

On the other hand, at the time of film formation, as shown in FIG.
By opening the light interrupter 503, the heating of the substrate 506 by the substrate heating device 511 is interrupted and the low-pressure mercury lamp 5
02 from the reaction chamber 5 through a light introduction window 504 made of a material that transmits ultraviolet light, such as synthetic quartz.
Irradiation is performed on the surface of the substrate 506 arranged in the substrate 05. At this time, the substrate 506 is heated to 200 to 300 degrees by the substrate heating heater 507 and the reaction chamber 505 is heated.
Is a vacuum exhaust device 50 such as a mechanical booster pump.
8, the gas is exhausted to a pressure of about 0.2 Torr, and the material gas 514 is supplied into the reaction chamber 505 at a flow rate of about 20 Torr.
Nozzle 510 for introducing SCCM SiH ₄ gas as material gas
Introduce through. This SiH ₄ passes through a mercury reservoir 509 in which mercury 500 heated to about 90 degrees is stored, and is mixed with mercury vapor for photoexcitation in a reaction chamber 50.
5 is introduced.

As a result, the mercury vapor is excited by the ultraviolet light from the light source 502, and the SiH ₄ gas is decomposed by the excited mercury, thereby generating SiH ₃ radicals as film-forming species. Then, the SiH ₃ radicals adhere to the substrate 506 to form an amorphous silicon film.

In the formation of this amorphous silicon thin film, before starting the film formation, the substrate 506 is heated in advance by the substrate heating device 511 provided in the light interrupter 503. Even without rising, it is stable. FIG. 14 is a characteristic diagram showing the relationship between the irradiation time and the substrate temperature. According to the present application , the substrate temperature is set to 250 ° C. before and after the start of film formation.
However, in the conventional case, the substrate temperature sharply rises immediately after film formation. This is because, in the conventional case, the substrate absorbs infrared light emitted from the light source immediately after the start of film formation. On the other hand, in the case of the present application , since the substrate 506 is preliminarily heated by the substrate heating device 511 until the substrate temperature rises due to the absorption of the infrared light emitted from the light source, the substrate temperature sharply decreases as in the related art. It does not rise.

Therefore, according to the present embodiment, it is possible to prevent a rapid rise in the substrate temperature at the start of the film formation, so that an amorphous silicon film having a uniform film quality in the film thickness direction can be obtained.

In order to minimize the change in the substrate temperature immediately after the film formation, the amount of heat given to the substrate 506 by the substrate heating device 511 and the amount of heat given to the substrate 506 by the light from the light source 502 should be the same. There is a need to.

In this embodiment , Si is used as a material gas.
The mercury-sensitized CVD apparatus using H ₄ has been described.
The method of the present application uses disilane (Si ₂ H ₆ ) as a material gas.
The present invention can also be applied to a direct excitation photo-assisted CVD apparatus using the method. next
A laminar flow type photo CVD apparatus using a mercury sensitization method according to another reference example of the present application will be described.

The difference between the photo-assisted CVD apparatus of this embodiment and those of FIGS. 12 and 13 described above is that, instead of an optical circuit breaker incorporating a substrate heating device, ultraviolet light is blocked and infrared light is transmitted. It consists in using a light blocker made of a material, for example, glass.

According to the optical CVD apparatus using such an optical circuit breaker, even if the optical circuit breaker is closed before the start of film formation, infrared light having a high heating effect is selectively selected from light from the light source. The substrate temperature is increased because the substrate is irradiated. On the other hand, in the conventional photo-CVD apparatus, since a light interrupter made of Al or stainless steel is used, the substrate temperature cannot be increased before the start of film formation as in this embodiment .

[0146] Thus, even in the optical CVD device of this reference example, as in the previous reference example, can be pre-heating the substrate prior to film formation, it is possible to prevent a rapid rise of the substrate temperature immediately after formation of the film, the film thickness direction A film such as a high quality amorphous silicon film having a uniform film quality can be formed. FIG.
5 shows light C using the mercury sensitization method according to another reference example of the present application.
It is a schematic diagram which shows the schematic structure of a VD apparatus.

In the figure, reference numeral 601 denotes a reaction chamber, in which a slit nozzle 602 is provided. The slit nozzle 602 allows the mercury vapor 603 and the carrier gas 604 (for example,
A mixed gas 611 with Ar gas) can be introduced into the reaction chamber 601. At this time, it is desirable to heat the mercury reservoir 612 to about 90 ° C. in order to increase the vapor pressure of mercury.

The substrate 60 is located below the reaction chamber 601.
A sample stage 616 on which the sample No. 5 is placed is installed. The sample stage 616 incorporates a substrate heating heater 606 for heating the substrate 605. On the other hand, a light source 607 composed of, for example, a low-pressure mercury lamp is provided above the reaction chamber 601, and light from this light source 607 is irradiated on the substrate 605 through the light transmission window 608. I have.

Further, Si generated by the mercury sensitization reaction
Radicals such as H ₃ are pressed against the substrate side, and the light transmitting window 60 is pressed.
A mesh nozzle 609 for blowing out the material gas 610 from the vicinity of the light transmission window 608 is provided in order to prevent radicals from flying to the nozzle 8. Here, the mesh nozzle 6
Since the ability to prevent radicals from flying to the light transmission window 608 is determined by the flow rate of the gas blown out of the mesh nozzle 609, an inert gas such as Ar or hydrogen gas is added to the material gas 610 in order to increase the flow rate of the gas blown out of the mesh nozzle 609. Etc. may be mixed.

The specific film forming conditions are described below.
While maintaining the internal pressure at about 0.5 Torr, introducing 0.6 SLM of Ar gas from the slit nozzle 602,
0.1 SLM of silane gas (SiH ₄ ) and 4.4 SLM of Ar gas are introduced from the mesh nozzle 609.
Then, the illuminance of the ultraviolet light is about 30 mW / c on the substrate 605.
m ² To form an amorphous silicon film.

According to the photo-assisted CVD apparatus of the present embodiment, the SiH ₄ gas blown out from the mesh nozzle 609 and the mercury blown out from the slit nozzle 602 form the region 6 near the substrate.
13, a mixed gas 614 of SiH ₄ gas and mercury gas is formed in a region 613 near the substrate, and the light irradiation there generates SiH ₃ radicals directly contributing to the film formation and transported to the substrate 605. Is done.

Therefore, compared with the case where a mixed gas of silane gas and mercury gas formed in advance outside the reaction chamber 601 is introduced into the reaction chamber 601, SiH ₃ radicals directly contributing to the film formation are deposited on the substrate 605. The time to fly is reduced.

Therefore, according to the present embodiment , SiH ₃
Since the radicals can be prevented from being decomposed into SiH ₂ radicals that have an adverse effect on film formation before flying to the substrate surface, a high-quality amorphous silicon film having a uniform film quality in the substrate surface can be obtained. Next, an optical CVD apparatus using a mercury sensitization method according to another reference example of the present application will be described.

The optical CVD apparatus of the present embodiment is different from that of FIG. 15 described earlier in that an optical filter is provided on the surface of the light transmitting window 608, and among the ultraviolet light contained in the light from the light source,
The object of the present invention is to absorb ultraviolet light having a wavelength of 185 nm by the optical filter and to introduce ultraviolet light having a wavelength of 254 nm into the reaction chamber.

According to the photo-assisted CVD apparatus configured as described above, a material containing Si atoms, such as disilane (Si ₂
H ₆ ), trisilane (Si ₃ H ₈ ), tetrasilane (n
-Si ₄ H ₁₀ ) or the like can reduce the amount of reactive products generated by ultraviolet light irradiation near the light transmission window. For this reason, since the amount of the reaction product adhered to the light transmission window can be reduced, it is possible to prevent the non-uniformity of the film quality and the reduction of the film formation speed due to the reduction of the light irradiation amount.

In the example of this embodiment , the formation of an amorphous silicon film is described. However, the present invention can be applied to the formation of a semiconductor thin film such as a microcrystal. Further, when a film of amorphous SiC or amorphous SiN is formed, a light transmission window is formed by a mixed gas of a gas that does not absorb light from a light source such as methane, hydrogen, nitrogen, and ammonia, and a material gas such as silane or disilane. Purging is also an effective method. Furthermore, in the example of the present embodiment , a general photo-assisted CVD apparatus has been described, but the present invention can also be applied to a laminar flow-type photo-assisted CVD apparatus in which a gas flows along the surface of a substrate.

It should be noted that the present invention is not limited to the above-described embodiments, and the above-described embodiments may be variously combined. In addition, various modifications can be made without departing from the scope of the present invention.

[0158]

As described in detail above, the present invention (claim 1)
According to the method, a second gas is supplied downstream from an etching gas supplied from a first gas nozzle commonly used for supplying a material gas.
Gas nozzles are provided.

For this reason, the etching species supplied from the second gas nozzle sufficiently spreads the etching species also on the downstream side. Therefore, the etching rate on the downstream side is higher than that of the conventional CVD apparatus, so that the cleaning time in the reaction chamber is greatly reduced, and the throughput can be improved.

Further, according to another CVD apparatus of the present invention (claim 2), the gas nozzle is movable in the downstream direction of the etching gas. By moving the gas nozzle in the downstream direction, the etching species is sufficiently supplied to the downstream region. Therefore, since the etching rate on the downstream side is increased, the cleaning time in the reaction chamber is significantly reduced, and the throughput can be improved.

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167]

[0168]

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical CVD apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an optical CVD apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram (at the time of film formation) when an optical CVD apparatus according to another embodiment of the present invention is viewed from the side.

FIG. 4 is a schematic configuration diagram (at the time of etching) of a schematic configuration diagram when a photo CVD apparatus according to another embodiment of the present invention is viewed from the side.

FIG. 5 is a schematic configuration diagram (at the time of etching) when a photo CVD apparatus according to another embodiment of the present invention is viewed from above.

FIG. 6 is a schematic configuration diagram of an optical CVD apparatus according to another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of an optical CVD apparatus according to another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of an optical CVD apparatus according to a reference example of the present application .

FIG. 9 is a characteristic diagram showing a relationship between a substrate temperature and a deposition rate.

FIG. 10 is a characteristic diagram showing a relationship between a substrate temperature and an etching rate.

FIG. 11 is a schematic configuration diagram of an optical CVD apparatus according to a reference example of the present application .

FIG. 12 is a schematic configuration diagram of an optical CVD apparatus according to a reference example of the present application .

FIG. 13 is a schematic configuration diagram of an optical CVD apparatus according to a reference example of the present application .

FIG. 14 is a view for explaining effects of the reference example of the present application .

FIG. 15 is a schematic configuration diagram of an optical CVD apparatus according to a reference example of the present application .

FIG. 16 is a schematic configuration diagram (side view) of a conventional photo-CVD apparatus.

FIG. 17 is a schematic view (top view) showing a schematic configuration of a conventional photo-CVD apparatus.

FIG. 18 is a schematic view (front view) showing a schematic configuration of a photo-CVD apparatus.

[Explanation of symbols]

101: reaction chamber, 102: stage, 103: substrate, 1
04: hot plate, 105a (first gas nozzle), 105b (second gas nozzle): slit nozzle, 106: heater 107: light introduction window, 108: mesh plate, 109: flow guard plate, 110
... Purge gas, 111 ... Exhaust port, 112 ... Exhaust pump,
Reference numeral 113: cleaning electrode (discharge electrode for removing an adherend); 114, a protective film; 115, a light source; 116, a lamp house; 117, a reflecting plate; 118, a holder plate;
... pipe, 121 ... etching gas, 122 ... material gas. 201: reaction chamber, 202: stage, 203: substrate, 204: hot plate, 205: slit nozzle (gas nozzle), 205a: nozzle holder, 205b
... Slit nozzle body, 207 ... Light introduction window, 208 ... Mesh plate, 209 ... Flow guard plate, 21
0: purge gas, 211: exhaust port, 212: exhaust pump, 213: cleaning electrode, 214: protective film, 2
15: Light source, 216: Lamp house, 217: Reflector,
218: Holder plate, 219: Pipe, 221: Etching gas, 222: Material gas, 223: Heater. 30
0: mercury, 301: lamp house, 302: light source, 30
3 ... reflection plate, 304 ... light introduction window, 305 ... reaction chamber, 30
Reference numeral 6: substrate, 307: heater for substrate heating, 308: vacuum pump, 309: mercury reservoir, 310a: material gas introduction nozzle, 310b: purge gas introduction nozzle, 311: purge gas introduction nozzle plate, 312: gas flow control plate, 3
13 ... exhaust port, 314 ... cleaning electrode, 315 ...
High frequency power supply, 321, bottom of reaction chamber, 322, heater for heating around the substrate, 323, pipe for cooling water, 324, valve for introducing material gas, 325, valve for introducing etching gas, 326, valve for introducing refrigerant, 327 ... 1 temperature control device, 328 ... second temperature control device, 329 ... main control device, 331 ... etching gas, 332 ... material gas, 3
33 ... cooling water. 400 ... mercury, 401 ... lamp house,
Reference numeral 402: light source, 403: reflector, 404: light introduction window, 4
05: reaction chamber, 406: substrate, 407: heater for heating the substrate, 408: vacuum pump, 409: mercury reservoir, 410
a: Material / etching gas introduction nozzle (gas nozzle),
410b ... Purge gas introduction nozzle, 411 ... Purge gas introduction nozzle plate, 412 ... Gas flow control plate, 413 ...
Exhaust port, 414: Cleaning electrode, 415: High frequency power supply, 421: Reaction chamber bottom, 422: Heater for heating around the substrate, 424: Material gas introduction valve, 425 ... Etching gas introduction valve, 426 ... Refrigerant introduction valve , 4
27: first temperature control device, 428: second temperature control device, 429: main control device, 431: etching gas, 4
32: Material gas, 433: Heat medium circulation pipe. 500 ...
Mercury, 501: Lamp house, 502: Low pressure mercury lamp, 503: Light circuit breaker, 504: Light introduction window, 505: Reaction chamber, 506: Substrate, 507: Heater for substrate heating, 5
08: vacuum evacuation device, 509: mercury reservoir, 510: material gas introduction nozzle, 511: substrate heating device (heating means),
512: cooling device, 513: reflector, 514: material gas. 601: reaction chamber, 602: slit nozzle (first gas nozzle), 603: mercury vapor, 604: carrier gas, 605: substrate, 606: heater for heating the substrate, 60
7, a light source, 608, a light transmitting window, 609, a mesh nozzle (second gas nozzle), 610, a material gas, 611, a mixed gas (mercury vapor + carrier gas), 612, a mercury reservoir,
613, 614 ... mixed gas (material gas + mercury gas),
615: area near the substrate, 616: sample stage.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiki Ishizuka 1 Toshiba-cho, Komukai-shi, Kawasaki-shi, Kanagawa Prefecture Inside the Toshiba R & D Center Co., Ltd. No. 1 Toshiba R & D Center Co., Ltd. (72) Inventor Hidetoshi Nozaki No. 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center Co., Ltd. (56) References JP-A-4-214873 (JP, A JP, A 58-95818 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/205

Claims (2)

(57) [Claims] A reaction chamber for accommodating a substrate and performing film formation; a gas nozzle for supplying a material gas for film formation into the reaction chamber; and a light source for supplying light to the material gas introduced into the reaction chamber. A light irradiating means for irradiating the substrate, a gas nozzle for supplying an etching gas for removing the adherend into the reaction chamber, and a discharge electrode for removing the adherend provided in the reaction chamber. In the apparatus, the gas nozzle for supplying the etching gas includes the gas nozzle,
A CVD apparatus comprising: a first gas nozzle commonly used as the gas nozzle for supplying a material gas; and a second gas nozzle provided downstream of the gas supplied from the first gas nozzle. 2. A reaction chamber for accommodating a substrate and forming a film, a gas nozzle for supplying a material gas for film formation or an etching gas for removing an adherend into the reaction chamber, In a CVD apparatus comprising: a light irradiation unit for irradiating the introduced material gas with light; and a discharge electrode for removing an adherend provided in the reaction chamber, wherein the gas nozzle is located downstream of an etching gas. A CVD apparatus characterized by being movable in directions.