JPH01109714A - Vapor-phase epitaxy appratus - Google Patents

Abstract

PURPOSE:To decrease the difference in flow rate of gas discharged from gas discharging small holes and to improve the uniformity of formed films, by supplying gas to a plurality of nozzle tubes divided in the length, independently from each other. CONSTITUTION:Gas supply nozzle tubes 5 and 6 which have been divided in the length from each other are supplied with gas independently from each other through a mass flow (MF) controller 10. The gas supplied to the nozzle tubes 5, 6 respectively is discharged through gas discharging small holes 7, 8 approxi mately in parallel to the surfaces of wafers 3. In this manner, it is possible to decrease difference in flow rate of the gas discharged from the gas discharg ing small holes 7, 8 and hence difference in thickness of films formed on the various wafers. Consequently, the uniformity in film thickness can be improved substantially.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vapor phase growth apparatus, and in particular, a vapor phase growth apparatus in which a large number of wafers are stacked at arbitrary intervals substantially horizontally in a vertical reaction tube. Regarding a vapor phase growth apparatus.

[Conventional technology]

Conventionally, this type of vapor phase growth apparatus, as shown in FIG.
A nozzle tube 11 with a large number of gas discharge holes 7 is installed in the tube wall, and the gas is distributed through the gas discharge holes 7 almost parallel to the wafer surface.
The structure is such that a new film is grown on the wafer surface. At this time, the nozzle pipe 11 was a single continuous pipe in the length direction.

[Problem that the invention seeks to solve]

In the conventional vapor phase growth apparatus described above, the flow rate of gas released from the gas release hole 7 decreases as it goes downstream, that is, above the wafer port, due to pressure loss within the nozzle pipe 11. Therefore, as the nozzle tube 11 becomes longer, the thickness of the film grown on the wafer 3 mounted on the wafer boat becomes thinner as it goes upward. As a result, there is a drawback that the number of wafers that can be grown at once decreases in order to reduce the difference in film thickness between wafers.

[Means for solving problems]

According to the present invention, a plurality of wafers are installed in a vertical reaction tube so as to be stacked approximately horizontally at arbitrary intervals, and a nozzle tube is installed approximately vertically in the vicinity of the wafers,
In a vapor phase growth apparatus that deposits a film on a wafer by ejecting gas from a number of pores in a nozzle tube, the nozzle tube is divided into multiple parts in the length direction. A vapor phase growth apparatus is obtained in which gases are supplied independently to each other.

According to the present invention, when the length of the wafer mounting portion of the wafer port is constant, the larger the number of divisions, the smaller the difference in gas flow rate from the gas discharge pores of each nozzle, and the difference in film thickness between wafers can be reduced. Can be made smaller.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a vapor phase growth apparatus according to an embodiment of the present invention, and a case in which silicon epitaxial growth is performed using this apparatus will be described.

The reaction tube has a double structure of an outer tube 1 and an inner tube 2.

Seventy wafers 3 each having a diameter of 150 mm were mounted on a wafer board 4 almost horizontally at intervals of about 6 mm. Regarding the nozzle pipe according to the present invention, the gas supply nozzle pipes 5 and 6 divided in the length direction are each independently provided with Si
HiCj22 and H2 gas are mask low controller (M
F) is adapted to be supplied through 10. The gas supplied to each nozzle pipe is discharged from the gas discharge holes 7 and 8, respectively, approximately parallel to the wafer surface.

An example of a silicon epitaxial growth experiment is shown below.

The temperature inside the reaction tube was brought to 1100° C. by heating in an electric furnace. 0.3 of the reaction gas SiH2CII 2 from the nozzle pipe 5
u/min, carrier gas H2 at 20A/min, and SiH2CR20, 3j7/min from the nozzle pipe 6.
n, H220β/min was flowed. The wafer port rotated at a rotational speed of 10 revolutions per minute (10 rpm). As a result, the wafers 3 installed in the lower and upper halves of the wafer port 4 show almost the same film thickness distribution, and it is possible to suppress the film thickness difference between wafers to within ±5% for all wafers. did it.

On the other hand, when the film was grown using a conventional single nozzle shown in FIG. 2, the film thickness difference between wafers was as large as ±12%.

Next, by dividing the nozzle into three parts, silicon epitaxial growth was similarly attempted on 70 mounted wafers. S i H2Cj22 at 0.3A/min and carrier gas H2 at 20j7/mi in each divided nozzle pipe.
n flowed. As a result, it was possible to suppress the film thickness distribution between wafers to ±3% or less. That is, if the number of divisions is increased, equipment such as a gas supply system becomes more complicated, but the uniformity of the film thickness improves.

〔Effect of the invention〕

In the present invention, wafers are stacked almost horizontally with arbitrary intervals in a vertical reaction tube, and the wafer surface is ejected from a gas discharge hole drilled in the wall of a nozzle tube erected almost vertically. This is a vapor phase growth device that supplies gas almost horizontally to the nozzle tube. By dividing the nozzle tube in the length direction and supplying gas to each divided section independently, the difference in gas flow rate between each gas discharge pore tube is reduced. be able to. As a result, the difference in film thickness between the wafers of the film grown on each wafer can be reduced, which has the effect of significantly improving the uniformity of film formation.

Further, although the above explanation has been given using silicon epitaxial growth as an example, it can also be applied to the formation of various oxide films, nitride films, polysilicon films, and amorphous silicon films, and its application value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vapor phase growth apparatus according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional vapor phase growth apparatus. 1...Reaction tube (outer tube), 2...Reaction tube (inner tube), 3...Wafer, 4.Old...Wafer po), 5゜6... ...Gas supply nozzle pipe, 7,
8...Gas release pore, 9...Exhaust port,
10...Masklow controller, 11. Old...Nozzle pipe. Agent Patent Attorney Shinkan Uchihara 1 Figure $ 2 Area

Claims (1)

[Claims] A plurality of wafers are installed in a vertical reaction tube so as to be stacked almost horizontally at arbitrary intervals, and a nozzle tube is installed almost vertically in the vicinity of the wafer, and a gas can be introduced into the nozzle tube. In a vapor phase growth apparatus that forms a film on the wafer by emitting water from a large number of pores, the nozzle pipe is divided into a plurality of parts in the length direction, and each of the divided nozzle pipes has an independent film. A vapor phase growth apparatus characterized in that a gas is supplied.