JPS62244126A - Vapor growth device - Google Patents

Abstract

PURPOSE:To ensure the uniformity of the quality and thickness of a vapor growth film on a semiconductor wafer by repeating vapor growth to a second exhaust section from a first reaction-gas supply section and to a first exhaust section from a second reaction-gas supply section under the state in which the temperature of the semiconductor wafer in a reaction pipe is kept constant in the vertical direction. CONSTITUTION:A first reaction-gas supply section 14 and a first exhaust section 15 are mounted to the upper section of a quartz reaction pipe 12 and a second reaction-gas supply section 17 and a second exhaust section 18 to a lower section. A reaction gas is introduced to the second exhaust section 18 from the first reaction-gas supply section 14 and to the first exhaust section 15 from the second reaction-gas supply section 17 under the state in which temperatures among semiconductor wafers 19 in the reaction pipe 12 are kept constant in the vertical direction, and vapor growth is repeated, thus ensuring the uniformity of the quality and thickness of vapor growth films on the semiconductor wafers 19.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vapor phase growth apparatus for growing a thin film on a semiconductor wafer in the manufacturing process of semiconductor devices.

BACKGROUND ART In the semiconductor manufacturing process, wafer diameters are increasing from 5 inches to 6 inches to 8 inches in parallel with efforts toward higher integration and miniaturization of devices. It goes without saying that in recent years, polycrystalline silicon films, silicon nitride films, silicon oxide films, and the like have played an important role as conductive film and insulating film materials. Currently, a vapor phase growth apparatus is selected and used depending on the growth temperature conditions of the thin film, characteristics of the grown thin film, throughput (output), etc. in the device manufacturing process. In particular, in batch-type vapor phase growth systems using horizontal diffusion furnaces with high throughput, we are working to develop vertical vapor phase growth systems to accommodate automation that takes into account large-diameter wafers and unmanned operation.

An example of the conventional vapor phase growth apparatus mentioned above will be described below with reference to the drawings. FIGS. 2 and 3 show the configuration of a conventional vapor phase growth apparatus. In Figure 2,
1 is a resistance heater, and a quartz reaction tube 2 is housed inside. N2 gas and reaction gas are supplied into the quartz reaction tube 2 through a vacuum shutoff valve 3 in the upper part of the quartz reaction tube 2 and a N2 gas supply on-off valve 4 and a reaction gas on-off valve 5 in the lower part. 6 is a semiconductor wafer loaded on a carrier boat 7, and the carrier boat 7 is vacuum-sealed by a door 8 and can be rotated by an external mechanism (not shown in the drawing). can.

Further, the door portion 8 can be moved up and down by a mechanism provided externally apart from the above-mentioned mechanism.

The operation of the vapor phase growth apparatus configured as described above will be described below.

First, the semiconductor wafers 6 loaded onto the carrier boat 7 are transferred to the quartz reaction tube 2 which has been heated by the resistance heater 1 in advance via the up-and-down mechanism connected to the door section 8.
inserted within. At this time, the inside of the quartz reaction tube 2 is filled with N2 gas via the N2 gas on-off valve 4. After the insertion is completed, the N2 gas on-off valve 4 is closed, the vacuum cutoff valve 3 is opened with the door 8 sealed, and the inside of the quartz reaction tube 2 is evacuated under reduced pressure. Thereafter, the carrier boat 7 is rotated by the rotation mechanism, and while the temperature of the semiconductor wafer 6 reaches a predetermined temperature, the vacuum cutoff valve 3 is simultaneously closed and the quartz reaction tube 2 is heated. After the predetermined temperature and leak check are confirmed, the vacuum cutoff valve 3 and the reaction gas on-off valve 6 are opened, the reaction gas is supplied into the quartz reaction tube 2, and vapor phase growth is performed on the semiconductor wafer 6. At this time, the set temperature of the resistance heater 1 is not uniform, but is set at an incline in advance. It is possible to make the film thickness distribution of the semiconductor wafer 6 uniform with respect to the adjacent portion). Furthermore, the in-plane film thickness distribution within the semiconductor wafer 6 can be made uniform by rotating the semiconductor wafer 6 on the carrier boat 7. After the vapor phase growth is completed, the reaction gas on-off valve 6 is closed, and the inside of the quartz reaction tube 2 is evacuated under reduced pressure. Next, the vacuum cutoff valve 3 is closed, and N2 gas is supplied into the quartz reaction tube 2 via the N2 gas on-off valve 4, so that the inside of the quartz reaction tube 2 becomes atmospheric pressure. Thereafter, the N2 gas on-off valve 4 is closed, and the semiconductor wafer 6 on the carrier boat 7 is taken out of the quartz reaction tube 2 by the up-and-down mechanism with the rotation stopped, completing the vapor phase growth process. do.

FIG. 3 shows a conventional example of a conventional vapor phase growth apparatus using a horizontal diffusion furnace, and since the semiconductor wafer 9 on the carrier boat is placed at the bottom of the quartz reaction tube 10, it is impossible to rotate it. However, as the diameter of the semiconductor wafer 9 increases, the film thickness distribution within the semiconductor wafer surface becomes worse.

Problems to be Solved by the Invention However, in the above configuration, the temperature is sloped in order to make the film thickness distribution uniform among the semiconductor wafers in the reaction tube, so the film thickness distribution is uniform. However, there was a problem in that thin films with different film qualities (eg, crystal diameter, stress, and impurity diffusion distribution) were grown in a vapor phase.

In view of the above-mentioned problems, the present invention generates a vapor-phase grown film while keeping the temperature between the substrates on the carrier boat in the reaction tube constant in the vertical direction, thereby making the film thickness and film quality distribution uniform. It provides equipment.

Means for Solving the Problems In order to solve the above problems, the vapor phase growth apparatus of the present invention includes:
In a vapor phase growth apparatus in which a heating element is arranged vertically around the periphery and a semiconductor wafer is held rotatably around a vertical axis,
The reaction tube housed inside the heating body is provided with a first reaction gas supply part and a first exhaust part at the upper part, and a second reaction gas supply part and a second exhaust part at the lower part. .

Effect of the present invention With the above-described configuration, even when the temperature inside the reaction tube is not given a gradient, the reaction gas is supplied from the first reaction gas supply section to the second exhaust section, and then the reaction gas is supplied to the second exhaust section. By supplying the reactive gas from the reactive gas supply section to the first exhaust section to perform vapor phase growth, it is possible to approximately equalize the vapor phase growth reaction in the vertical direction and ensure uniform film thickness. Moreover, since it is possible to make the temperature inside the reaction tube uniform in the vertical direction, it is also possible to ensure uniformity of the film quality.

EXAMPLES Hereinafter, vapor phase growth apparatuses according to examples of the present invention will be described with reference to standards.

FIG. 1 shows a configuration diagram of a vapor phase growth apparatus in an embodiment of the present invention. Polycrystalline silicon C and below PO17-3
In FIG. 1, a resistive heater (denoted as L) performs vapor phase growth, 11 is a resistance heater (heating body), and a quartz reaction tube (reaction tube) 12 is housed inside. The quartz reaction tube 12
A first N2 gas on-off valve 13 for supplying N2 gas is installed on the top of the
1. First reaction gas on-off valve for supplying two reaction gases (first reaction gas supply section) 14. and a first vacuum cutoff valve (first exhaust section) 15 are connected. Further, a second N2 gas on-off valve 16 for supplying N2 gas is provided at the bottom of the quartz reaction tube 12,
A second reaction gas on-off valve (second reaction gas supply section) 17 for supplying the reaction gas and a second vacuum cutoff valve (second exhaust section)
18 are connected. The semiconductor wafer 19 is loaded onto a carrier boat 20, and the carrier boat 2o is vacuum-sealed with a door 21 and can be rotated by an external mechanism (not shown in the drawings). can. Further, the door portion 21 can be moved up and down by a mechanism provided externally in addition to the above-mentioned mechanism.

The operation of the vapor phase growth apparatus configured as described above will be described below with reference to FIG. 1.

First, FIG. 1 shows a Po1y-3i vapor phase growth apparatus, in which wafers 19 loaded on a carrier boat 20 are preliminarily transferred to a resistance heater 11 via the vertical mechanism connected to a door 21. The tube is inserted into a quartz reaction tube 12 heated to about 616°C. At this time, inside the quartz reaction tube 12 are first and second N2 gas on-off valves 13.
16 with N2 gas. After the insertion is complete,
The N2 gas on-off valve 13.16 is closed, and the first and second vacuum cutoff valves 15.18 are closed with the door section 21 sealed.
is opened, and the inside of the quartz reaction tube 12 is evacuated under reduced pressure.

Thereafter, the carrier boat 2° is rotated by the rotation mechanism, and the temperature of the semiconductor wafer 19 is increased by the resistance heating heater 1.
The temperature is maintained until it becomes equal to the set temperature of 1 (about 10 to 16 minutes), and at the same time the first and second vacuum cutoff valves 15.18
is closed, and the adhesive inside the quartz reaction tube 12 is formed. After the reached temperature and leak check are confirmed, the monosilane (SiH4) connected to the lower part of the quartz reaction tube 12
Second reaction gas on-off valve 17 that supplies gas (reaction gas)
Then, the first vacuum cutoff valve 16 connected to the upper part of the quartz reaction tube 12 is opened, and Po1y-3L is vapor-phase grown onto the semiconductor wafer 19 at a pressure of about 0.2 to 0.3 Torr. Also, after a certain amount of vapor phase growth has been carried out, the second
The reaction gas on-off valve 1T is closed, the inside of the quartz reaction tube 12 is evacuated under reduced pressure, and the first vacuum cutoff valve 16 is closed. next,
The second vacuum shutoff valve 18 connected to the lower part of the quartz reaction tube 12 and the first reaction gas on-off valve 14 connected to the upper part of the quartz reaction tube 12 are opened, and the pressure is about 0.2 to 0.37 orr. Vapor phase growth of PO17-3t onto the semiconductor wafer 19 is performed. At this time, the set temperature of the resistance heater 11 is not inclined, and the temperature of the substrate on the carrier board 20 is almost uniform. As described above, the flow direction of the 5in4 gas is repeated from top to bottom and from bottom to top to ensure uniformity of film thickness during vapor phase growth. However, the film thickness distribution between the semiconductor wafers 19 during each vapor phase growth process is measured in advance. After the vapor phase growth is completed, the inside of the quartz reaction tube 12 is evacuated under reduced pressure with the first and second reaction gas on-off valves 14, 17 closed.

Next, with the first and second vacuum cut-off valves 15, 18 closed, the first and second N2 gas on-off valves 13.16 are opened, and N2 gas is supplied into the quartz reaction tube 12. The inside of the quartz reaction tube 12 becomes atmospheric pressure. After that, the first and second N2
The gas on-off valves 13 and 16 are closed, and the semiconductor wafers 19 on the carrier boat 20 are taken out of the quartz reaction tube 12 by the up-and-down mechanism while rotation is stopped, and all vapor phase growth processing is completed.

As described above, according to this embodiment, the reaction gas supply section 14 and the first exhaust section 16 .
By providing the second reaction gas supply section 17 and the second exhaust section 18 at the lower part, the semiconductor wafer 19 inside the reaction tube 12 is
The reaction gas is supplied from the reaction gas supply section 14 of f$1 to the second exhaust section 18 and from the second reaction gas supply section 17 to the first exhaust section 16 while keeping the temperature between them constant in the vertical direction. By repeating vapor phase growth, semiconductor wafers19
Uniformity in film quality and film thickness of the above vapor phase grown film can be ensured.

In this embodiment, a resistance heater is used as the heating element 11, but a lamp heater may also be used. In addition, the vapor growth layer is not only Po1y-8i, but also
By changing the composition of the reaction gas, an 813N4 film (silicon nitride film), a SiO2 film (silicon oxide film), etc. may be used.

Effects of the Invention As described above, the present invention provides a vapor phase growth apparatus in which a heating body is arranged vertically around the periphery and a semiconductor wafer is rotatably held around a vertical axis. By providing a first reaction gas supply section and a first exhaust section at the top of the tube, and a second reaction gas supply section and second exhaust section at the bottom, the temperature of the semiconductor wafer inside the reaction tube can be kept constant in the vertical direction. in the state where the first reactant gas supply section
By repeatedly performing vapor phase growth from the exhaust section and the second reaction gas supply section to the first exhaust section, uniformity in film quality and thickness of the vapor phase grown film on the semiconductor wafer can be ensured. .

[Brief explanation of drawings]

FIG. 1 is a block diagram of a vapor phase growth apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of conventional vapor phase growth apparatuses, respectively. 11... Heating body, 12... Reaction tube, 1
4...First reaction gas supply section, 16...
・First exhaust part, 17... Second reaction gas supply part, 18... Second exhaust part, 19...
semiconductor wafer. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Figure + 1-Jl Anti-Noguchi 1s1 (-taCηo1shi\ii4()+
2- Shiyanchengying C and X, Leopard Figure 2, 9 Figure 3

Claims (1)

[Claims] In a vapor phase growth apparatus in which a heating element is arranged vertically around the periphery and a semiconductor wafer is held rotatably in the vertical direction,
A first reaction gas supply section and a first exhaust section are provided at the upper part of the reaction tube housed inside the heating body, and a second reaction gas supply section and a second exhaust section are provided at the lower part. Vapor phase growth equipment.