JPS5855254Y2 - Equipment for reduced pressure vapor phase growth - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement of an apparatus for reduced pressure vapor phase growth.

Conventionally, as a reduced pressure vapor phase growth apparatus, as shown in FIG. On the side opposite to the open end 1 side of the reaction tube 4 for vapor phase growth, there is an exhaust pump 6 that extends an exhaust tube 5 that communicates with the atmosphere. 7, and a check valve 9 is inserted between the vapor growth reaction tube 4 and the on-off valve 7 in the exhaust main pipe 8, and the exhaust gas is connected to the atmosphere. A configuration has been proposed in which a branch pipe 10 is connected to the reactor tube 4 for vapor phase growth, and a heater 11 is arranged around the reaction tube 4 for vapor phase growth to heat it.

According to such a device for low pressure vapor phase growth, the wafer 13 is placed in the reaction tube 4 for vapor phase growth via the boat 12, and the reaction tube 4 for vapor phase growth is closed by the door body 3. With the open end 1 closed, the exhaust pump 6 is driven with the on-off valve 7 opened, and the vapor phase growth reaction tube 4 is exhausted to the atmosphere through the main exhaust pipe 8, on-off valve 7, and exhaust. While heating the reaction tube 4 for vapor phase growth with the heater 11, the reaction tube 4 for vapor phase growth is heated via the gas introduction tube 2. A vapor-phase growth layer (for example, made of a semiconductor) can be obtained on the wafer 13 by introducing a gas for vapor-phase growth into the main pipe 8. This prevents the passing gas from being exhausted to the atmosphere via the exhaust branch pipe 10.

Further, according to the above-mentioned apparatus for low-pressure vapor phase growth, after obtaining the vapor phase growth layer on the wafer 13 by using it as described above,
Introducing a gas for vapor phase growth into the reaction tube 4 for vapor phase growth through the gas introduction tube 2, heating the reaction tube 4 for vapor phase growth with the heater 11, and removing gas by driving the exhaust pump 6. After stopping the exhaust to the atmosphere from the phase growth reaction tube 4, the door body 3 is closed.
The wafer 13 on which a vapor-phase growth layer has been obtained is taken out of the reaction tube 4 for vapor-phase growth, and then or before that, the on-off valve 7 is opened.
In order to keep the inside of the reaction tube 4 for vapor phase growth clean, a gas made of, for example, N2 is introduced into the gas introduction tube 2 with the tube closed.
In such a case, or when the vapor phase growth layer is obtained on the wafer 13 as described above, the exhaust pump 6 is introduced into the reaction tube 4 for vapor phase growth. If the drive of the vapor phase growth reaction tube 4 is stopped due to a power outage, for example, the gas pressure inside the vapor phase growth reaction tube 4 becomes higher than the atmospheric pressure and the vapor phase growth reaction tube 4 is not damaged. In this case, the check valve 9 opens, and the gas in the reaction tube 4 for vapor phase growth is discharged to the exhaust main pipe 8 and the exhaust branch pipe 10.
and escapes to the atmosphere via the check valve 9, thereby preventing the vapor phase growth reaction tube 4 from being damaged.

As mentioned above, according to the above-mentioned apparatus for reduced pressure vapor phase growth,
It is possible to obtain a vapor phase growth layer on the wafer 13 using this, but by having the check valve 9, the gas pressure in the reaction tube 4 for vapor phase growth is lower than atmospheric pressure to a predetermined pressure range. Even if the pressure exceeds a high pressure and the reaction tube 4 for vapor phase growth is not damaged, this can be prevented.

However, in the case of the above-mentioned apparatus for low-pressure vapor phase growth, when using it to obtain a vapor phase growth layer on the wafer 13 as described above, the vapor phase introduced into the reaction tube 4 for vapor phase growth is SiH4 or 5iH2C12 and 02 as growth gas
When using a gas containing at least PH3 and 02, a gas containing at least SiH4 or 5iH2C12 and NH3, etc., SiO2, P2O5, Si3H4, NH4Cl etc. are used in the reaction tube 4 for vapor phase growth. As a result of the generation of powdery solids, the gas pressure inside the vapor phase growth reaction tube 4 becomes higher than the atmospheric pressure as described above, and the check valve 9 opens, causing the vapor phase growth to occur. When the gas in the growth reaction tube 4 escapes to the atmosphere through the exhaust main pipe 8, the exhaust branch pipe 10, and the check valve 9, solid matter is deposited on the check valve 9, and as a result, solid matter is deposited on the wafer 13. When a vapor-phase growth layer is obtained, the check valve 9, which should be blocking the vapor-phase growth reaction tube 4 and the atmosphere, is not completely blocking the connection between the vapor-phase growth reaction tube 4 and the atmosphere. The gas pressure inside the wafer 13 could not be obtained as the desired pressure, and the inside of the reaction tube 4 for vapor phase growth was contaminated with gas from the atmosphere. This had the disadvantage that it could not be obtained as a product having the following properties.

Therefore, the present invention is based on the conventional apparatus for reduced pressure vapor phase growth shown in FIG. It will become clear from the detailed explanation.

FIG. 2 shows an example of an apparatus for low-pressure vapor phase growth according to the present invention. Parts corresponding to those in FIG. In this case, a filter 21 for removing solids contained in the gas passing through the exhaust branch pipe 10 is inserted into the exhaust main pipe 8 and check valve 9 of the exhaust branch pipe 10 in the open position, and Another check valve 22 that operates at a higher pressure than the check valve 9 is inserted in the main pipe 8 at a position between the vapor growth reaction tube 4 and the on-off valve 7, and another check valve 22 that operates at a higher pressure than the check valve 9 is used for other exhaust gas communication with the atmosphere. The configuration is the same as that shown in FIG. 2, except that the branch pipe 23 is connected to the exhaust branch pipe 10 through a part of the exhaust main pipe 8 side.

The above is an example of the configuration of the apparatus for reduced pressure vapor phase growth according to the present invention, but according to this configuration, it is the same as the case of FIG. 1 except for the matters mentioned above, so detailed explanation thereof will be omitted. However, as in the case of FIG. 1, the wafer 13 is placed in the reaction tube 4 for vapor phase growth, and the exhaust pump 6 is driven to exhaust the reaction tube 4 for vapor phase growth to the atmosphere. In addition, while heating the reaction tube 4 for vapor phase growth with the heater 11, it is used to introduce gas for vapor phase growth into the reaction tube 4 for vapor phase growth via the gas introduction tube 2. A vapor-phase growth layer can be obtained on the wafer 13, and in this case the check valves 9 and 22 are arranged such that the gas passing through the exhaust main pipe 8 is discharged to the atmosphere via the exhaust branch pipes 10 and 23, respectively. This is what prevents people from doing so.

Further, according to the structure of an example of the apparatus for low-pressure vapor phase growth according to the present invention described above, a detailed explanation thereof will be omitted, but in the same manner as described above with reference to FIG. 12 is taken out of the reaction tube 4 for vapor phase growth, in order to maintain the cleanliness inside the reaction tube 4 for vapor phase growth, a gas made of, for example, N2 is introduced into the reaction tube 4 for vapor phase growth through the gas introduction tube 2. When introducing the wafer 13 into the reaction tube 4, the wafer 13 is also introduced as described above.
If the drive of the exhaust pump 6 is stopped with a vapor growth layer formed on top of the vapor growth layer, the gas pressure inside the vapor growth reaction tube 4 will exceed atmospheric pressure and the gas will be removed. Even if the phase growth reaction tube 4 is not damaged, the check valve 9 will open in this case, and the gas in the vapor phase growth reaction tube 4 will flow through the exhaust main tube 8, the exhaust branch tube 10, the filter 21, and the check valve. It escapes to the atmosphere via the valve 9, thereby preventing the vapor phase growth reaction tube 4 from being damaged.

In this case, the check valve 22 remains closed because it operates at a higher pressure than the check valve 9, and therefore the check valve 22 is connected to the vapor growth reaction tube 4. It does not operate in order to release the gas inside to the atmosphere through the exhaust branch pipe 23.

Therefore, according to the configuration of an example of the apparatus for low pressure vapor phase growth according to the present invention, which is shown in FIG. A vapor phase growth layer can be obtained on the vapor phase growth layer 13, and by having the check valve 9, the gas pressure inside the vapor phase growth reaction tube 4 is higher than the atmospheric pressure and the gas is Even if the phase growth reaction tube 4 is not damaged, this can be prevented.

However, in the case of the apparatus for reduced pressure vapor phase growth according to the present invention, as mentioned above, the gas pressure in the reaction tube 4 for vapor phase growth exceeds the expected pressure level higher than atmospheric pressure, and the check valve 9 opens. When the gas in the vapor growth reaction tube 4 escapes to the atmosphere via the exhaust main pipe 8, the exhaust branch pipe 10, the filter 21, and the check valve 9, the gas passing through the exhaust branch pipe 10 is Even if the solid matter mentioned above in Figure 1 is contained, by having the filter 21, the solid matter is
1, thereby preventing solids from accumulating on the check valve 9. For this reason, when obtaining a vapor phase growth layer on the wafer 13, as in the case of FIG. This prevents a situation in which the check valve 9, which should be blocking the reaction tube 4 and the atmosphere, is not completely blocking the connection, and
Therefore, when forming a vapor phase growth layer on the wafer 13, the gas pressure in the vapor phase growth reaction tube 4 cannot be obtained as the desired pressure as in the case of FIG. This prevents the inside of the reaction tube 4 for vapor phase growth from being contaminated with gas from the atmosphere, and therefore makes it impossible to obtain a vapor phase growth layer on the wafer 13 with desired characteristics. The drawbacks of the conventional low pressure vapor phase growth apparatus described above with reference to FIG. 1 can be effectively avoided.

Furthermore, as the filter 21 removes solid matter, the filter 21 becomes clogged with solid matter, and as a result, the check valve 9 becomes inoperable, and the gas pressure in the reaction tube 4 for vapor phase growth is reduced to the non-return state. Even if the planned pressure length is higher than the pressure at which the valve 9 operates and the vapor phase growth reaction tube 4 is not damaged, the check valve 22 opens in this case, thereby causing the vapor phase growth reaction tube 4 to open. The gas inside escapes to the atmosphere through the exhaust main pipe 8, the exhaust branch pipe 23, and the check valve 22, thereby preventing the vapor phase growth reaction tube 4 from being damaged.

The above description merely shows an example of the present invention, and for example, as shown in FIG. 3, in the configuration described above in FIG. A filter 21' similar to the filter 21 and a check valve 9' similar to the check valve 9 are inserted in that order between the on-off valve 7 and an exhaust pipe similar to the exhaust branch pipe 10 communicating with the atmosphere. If the branch pipe 10' is connected and the gas pressure inside the vapor phase growth reaction tube 4 exceeds a pressure higher than the atmospheric pressure and the vapor phase growth reaction tube 4 is to be damaged, use a back check. Check valve 9' together with valve 9
Even if one of the check valves 9 and 9' does not open, the other opens, and the reaction tube 4 for vapor phase growth opens.
It is also possible to prevent damage to the reaction tube 4 for vapor phase growth, thereby making it possible to more reliably prevent damage to the reaction tube 4 for vapor phase growth, and various other modifications and changes may be made.

[Brief explanation of drawings]

Figure 1 is a route map showing a conventional low-pressure vapor phase growth equipment;
The figure is a route map showing an example of the apparatus for reduced pressure vapor phase growth according to the present invention, and FIG. 3 is a route map showing another example of the apparatus for reduced pressure vapor phase growth according to the present invention. In the figure, 2 is a gas introduction pipe, 3 is a door body, 4 is a reaction tube for vapor phase growth, 5 is an exhaust pipe, 6 is an exhaust pump, 7 is an on-off valve,
8 is the exhaust main pipe, 9.9' and 22 are check valves, 10°1
0' and 23 are exhaust branch pipes, and 21 and 21' are filters, respectively.

Claims (1)

[Scope of utility model registration request] It has a reaction tube for vapor phase growth into which gas for vapor phase growth is introduced, and an exhaust pump is connected to the reaction tube for vapor phase growth via an exhaust main pipe into which an on-off valve can be inserted, A reduced pressure vapor phase growth apparatus having a structure in which a check valve is inserted between the vapor phase growth reaction tube and the on-off valve in the exhaust main pipe, and an exhaust branch pipe communicating with the atmosphere is connected. A filter for removing solid matter contained in the gas passing through the exhaust branch pipe is inserted between the exhaust main pipe and the check valve of the exhaust branch pipe, and a filter is inserted between the exhaust main pipe and the check valve. Another check valve that operates at a higher pressure than the check valve is inserted between the vapor phase growth reaction tube and the on-off valve, and another exhaust branch pipe communicating with the atmosphere is connected. Equipment for reduced pressure vapor phase growth.