JPH0346234A - Horizontal type furnace for semiconductor treatment - Google Patents

Abstract

PURPOSE:To make uniform a gas concentration distribution or a distribution of temperature and the like and to make it possible to perform a uniform crystal growth and a treatment by a method wherein at least either gas introducing ports or gas discharge ports are provided a plurality in number, gas circulating paths in a furnace are formed into 2 or more and the gas in the furnace is made to flow so as to be able to change-over. CONSTITUTION:Gas introducing ports 2 and 3 and gas discharge ports 4 and 5 are respectively provided a plurality in number, gas circulating paths in a furnace are formed into two or more and the gas in the furnace is made to flow so as to be able to change-over by valves 11 to 18. With this the flow of gas in the reaction pipe 1 is changed-over from the direction shown by an arrow A to the direction shown by an arrow B. Thereby, a gas concentration distribution or a distribution of temperature and the like can be made uniform and a uniform epitaxial crystal growth or a semiconductor treatment, such as an activation of ion-implantation or the like, can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a horizontal furnace for semiconductor processing, which is used for semiconductor heat treatment, epitaxial growth, and the like.

[Prior Art] FIG. 3 is a schematic diagram showing a conventional horizontal furnace for semiconductor processing. Such a conventional horizontal furnace is described, for example, in "Practical Handbook of Semiconductor Processing Equipment," Science Forum, p. 58, 1.
It is shown in 984.

Referring to FIG. 3, flanges 37 are installed on both sides of the reaction tube 31.
and 38 constitute a horizontal furnace.

The flange 37 is provided with a gas inlet 32, and the flange 38 is provided with a gas outlet 33. Reaction tube 3
A sample 35 is placed on a susceptor 34 inside the reaction tube 1, and a heater 36 for heating the inside of the reaction tube 31 is provided around the reaction tube 31.

The inside of the reaction tube 31 is heated by the heater 36, gas is introduced into the reaction tube 31 from the gas inlet 32, and the gas inside the reaction tube 31 is discharged from the gas outlet 33. In this way, by continuously supplying gas into the reaction tube 31, semiconductor heat treatment such as epitaxial crystal growth or ion implantation is performed.

[Problems to be Solved by the Invention] As mentioned above, in the conventional horizontal furnace for semiconductor processing, there are a gas inlet for introducing gas into the furnace and a gas outlet for discharging the gas in the furnace. Since only one was provided, the gas flow path within the furnace was only one path from the gas inlet to the gas outlet.

Therefore, the direction in which gas flows in the furnace is only one direction, and a gas concentration distribution, temperature distribution, etc. occur in this direction. Such gas concentration distribution and temperature distribution cause a film thickness distribution and a carrier concentration distribution of an epitaxial crystal growth layer during, for example, epitaxial growth. Further, in the case of activation heat treatment of an ion-implanted wafer, it causes non-uniform activation.

The purpose of the present invention is to solve such conventional problems and to improve
An object of the present invention is to provide a horizontal furnace for semiconductor processing that can perform uniform crystal growth and processing.

[Means and effects for solving the problems] In the horizontal furnace for semiconductor processing of the present invention, by providing a plurality of at least one of the gas inlet and the gas outlet, two or more gas flow paths are provided in the furnace. It is characterized by being able to be switched.

In the horizontal furnace for semiconductor processing of the present invention, there are two or more gas distribution paths in the furnace, which can be switched.
By switching the gas flow path during activation heat treatment for epitaxial growth or ion implantation, the direction of gas flow in the furnace can be changed and the gas concentration distribution, temperature distribution, etc. can be made uniform.

[Embodiment] FIG. 1 is a schematic diagram showing an embodiment of the present invention. Referring to FIG. 1, flanges 9 are provided on both sides of the reaction tube 1.
and a flange 10 are provided. The flange 9 is provided with a gas introduction port 3, and the gas introduction port 3 is connected to a pipe 21 via a valve 13.
is connected to a gas supply pipe 20 via a valve 11.

Further, the flange 9 is provided with a gas discharge port 4,
The gas outlet 4 is connected to a pipe 23 via a valve 16. The pipe 23 connects to the gas exhaust pipe 25 via the valve 18.
It is connected to the.

The flange 10 is provided with a gas inlet 2, and the gas inlet 2 is connected to a pipe 22 via a valve 14. Piping 22 is connected to gas supply pipe 20 via valve 12 .

Further, the flange 10 is provided with a gas outlet 5, and the gas outlet 5 is connected to a pipe 24 via a valve 15. The pipe 24 is connected to a gas exhaust pipe 25 via a valve 17.

Gas to be supplied into the reaction tube 1 is passed through the gas supply pipe 20 , and this gas is exhausted through the gas discharge pipe 25 . A sample 7 placed on a susceptor 6 is placed inside the reaction tube 1 . Further, a heater 8 is provided around the reaction tube 1 to heat the inside of the reaction tube 1.

By keeping the valves 11 and 13 open and the valves 12 and 14 closed, the gas in the gas supply 20 passes through the pipe 21 and is supplied into the reaction tube 1 from the gas inlet 3. Further, by keeping the valves 15 and 17 open and the valves 16 and 18 closed, the gas in the reaction tube 1 is discharged from the pipe 24 to the gas discharge pipe 25 through the gas discharge port 5. In this state, reaction tube 1
The gas inside flows in the direction of arrow A shown in FIG. Gas concentration distribution, temperature distribution, etc. occur within the reaction tube 1 under such a flow.

FIG. 2 is a diagram showing the processing temperature in the furnace and the timing of switching the gas flow path. As shown in FIG. 2, the processing temperature in the furnace gradually rises to a predetermined temperature, is maintained at the predetermined temperature for a certain period of time, and then decreases. At point C shown in FIG. 2, the gas distribution route is switched to a distribution route different from the first half distribution route.

To explain this switching of the distribution route, returning to FIG. 1, valves 11 and 13 are closed, and valves 12 and 1 are closed.
4, stop the gas supply to pipe 21, and open pipe 2.
2, and introduce the gas into the reaction tube 1 from the gas inlet 2. Further, the valves 15 and 17 are closed and the valves 16 and 18 are opened to stop discharging the gas from the gas discharge port 5 and to discharge the gas from the gas discharge port 4 through the pipe 23 to the gas discharge pipe 25. As a result, the flow of gas in the reaction tube 1 is switched from the six directions of arrows to the direction of arrow B. Therefore, a new gas concentration distribution, temperature distribution, etc. based on the gas flow direction in the arrow B direction is generated, and these newly generated gas concentration distribution, temperature distribution, etc. are based on the gas flow direction in the arrow A direction. Since it cancels out gas concentration distribution, temperature distribution, etc., it is possible to make the gas concentration distribution, etc. uniform throughout the entire treatment process. By switching the gas flow path in this manner, distribution of the thickness and carrier concentration of the epitaxial layer, the activation rate of the ion-implanted layer, etc. can be made uniform.

Semi-insulating L obtained by liquid-sealed Czochralski method
28Si+ on EC-GaAs wafer at 120KeV,
Ions were implanted under the conditions of 3.0 x 10" cm-2. The GaAs wafer implanted in this way was heat treated using a horizontal furnace shown in Fig. 1.AsH gas was introduced into the furnace. 850℃ in this atmosphere
Heat treatment for activation was performed for 10 minutes. first half 5
The heat treatment was performed by opening valves 11, 13, 15, and 17 and closing valves 12, 14, 16, and 18 so that the gas flow in the furnace was in the direction of arrow A. Next, for the latter 5 minutes, the heat treatment was performed by closing valves 11, 13, 15 and 17, and opening valves 12, 14, 16 and 18 so that the gas flow in the furnace was in the direction of arrow B. .

Using the heat-treated wafer, FETs are manufactured and their threshold Iiii! When the in-plane voltage distribution was measured, vth was -2,915V, and the standard deviation of vth σvth was 3.
It was 8mV.

For comparison, using the apparatus shown in Figure 1, valves 11, 13, 15 and 17 were opened so that the gas flow was in the direction of arrow A from beginning to end without switching the gas flow midway. Heat treatment was performed with 12°14.16 and 18 closed. Using the resulting wafer, we fabricated an FET in the same manner as in the above example, and measured the in-plane distribution of its threshold voltage, and found that vth was -
2°966V, and its standard deviation σvth is 83mV
Met.

As is clear from this, by using the horizontal semiconductor processing furnace of the present invention and switching the gas flow path during the processing process, the in-plane distribution of the threshold voltage was made more than twice as uniform. Generally, when heat treatment is performed using conventional equipment without changing the gas flow path, activation is better on the upstream side of the gas, that is, vth shows a larger negative value, and activation is worse on the downstream side of the gas. So-called "one-sided flow".

However, by using the horizontal semiconductor processing furnace of the present invention and switching the gas flow path during the processing process, such one-sided flow can be prevented. In the above embodiment, the gas flow path is switched only once in the treatment process, but this switching can be repeated multiple times.

[Effects of the Invention] As described above, by using the horizontal furnace for semiconductor processing of the present invention, semiconductor processing such as uniform epitaxial crystal growth or ion implantation activation can be performed with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing the timing of switching the furnace processing temperature and the gas flow path. FIG. 3 is a schematic configuration diagram showing a conventional horizontal furnace for semiconductor processing. In the figure, 1 is a reaction tube, 2 and 3 are gas inlet ports, and 4.5
is a gas outlet, 6 is a susceptor, 7 is a sample, 8 is a heater,
9 and 10 are flanges, 11 to 18 are valves, 20 is a gas supply pipe, 21 to 24 are piping, and 25 is a gas discharge pipe. Figure 1 Figure 2 Ginclose

Claims (1)

[Claims] (1) In a horizontal semiconductor processing furnace in which gas is introduced into the furnace through a gas inlet and gas in the furnace is discharged through a gas outlet, at least one of the gas inlet and the gas outlet is provided in plural numbers. A horizontal furnace for semiconductor processing, characterized in that there are two or more gas flow paths in the furnace, which can be switched.