JPH09148259A - Lateral reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make uniform surface process of a wafer without requiring a movable mechanism being a dust source by a method wherein a plurality of exhaust ports are provided in a lower part of a furnace core tube opposite a plurality of gas blow-out ports which are arranged in an upper part of the furnace core tube, and which blow out reaction gas in a wafer column. SOLUTION: This lateral reactor is provided with a gas supply mechanism 1 arranged laterally with a plurality of gas blow-out ports 3a, 3b, 3c which are arranged in an upper part in a furnace core tube 6, and which introduce reaction gas; and a gas exhaust tube 2 provided with a gas exhaust port 4 which is arranged opposite gas blow-out ports 3a, 3b, 3c in a lower part in the furnace core tube, and which discharges reaction gas. The gas supply mechanism 1 comprises a plurality of gas introduction tubes 1a, 1b, 1c, and a flow volume valve is independently provided in each of the gas introduction tubes 1a, 1b, 1c so that a flow volume of reaction gas in the gas blow-out ports 3a, 3b, 3c is made constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate which is inserted in a long furnace core tube placed in a lateral direction and heated at a high temperature, and which is subjected to an oxidation / diffusion treatment or a polycrystalline process on a semiconductor substrate under an atmosphere of a reaction gas. The present invention relates to a horizontal reactor for forming a silicon film, a nitride film, etc.

[0002]

2. Description of the Related Art Conventionally, this type of horizontal reactor has been used for forming an oxide film, diffusing impurities, forming a nitride film or polycrystalline silicon on the surface of a semiconductor substrate (hereinafter simply referred to as a wafer). . However, since such a surface treatment takes time, a plurality of wafers are simultaneously treated in order to improve efficiency.

FIG. 2 is a schematic sectional view showing an example of a conventional horizontal reactor. As shown in FIG. 3, a horizontal reactor for processing a large number of wafers includes a furnace core tube 11 for accommodating a boat 13 in which a large number of wafers 14 are placed side by side in one direction, and an inside of the furnace core tube 11. And a heater 12 for heating at a high temperature. Then, a reaction gas is introduced from one side of the furnace core tube 11 to make the inside of the furnace core tube 11 at a constant pressure, and then an oxidation / diffusion process or a growth of a polycrystalline silicon film, a nitride film or the like is performed.

However, in this type of horizontal reactor, the concentration of the reaction gas is higher near the gas supply port and lower at the furnace port side regardless of the viscous flow region at a pressure of about 0.5 Torr. As a result, the active molecules of the reaction gas that come into contact with the wafer 14 become uneven, and there is a risk that variations in the surface treatment will occur among the wafers 14 mounted on the boat 13.

3 (a) and 3 (b) are a longitudinal sectional view and a lateral sectional view showing another example of a conventional horizontal reactor. As a vapor phase growth apparatus which is a kind of a horizontal reactor in which a gas supply mechanism is improved in order to uniformly grow a film thickness, Japanese Patent Application Laid-Open No. Sho 5 (1999)
It is disclosed in Japanese Unexamined Patent Publication No. 8-25224. As shown in FIG. 3, the vapor phase growth apparatus, which is a horizontal reactor, reacts a gas supply pipe 10 which has a plurality of injection ports and which supplies a reaction gas while moving along the inner wall of the reaction pipe 11a. Prepared in the pipe.

Further, in this vapor phase growth apparatus, the direction of gas injection from the gas supply pipe 10 is set to 10 from the axial center of the reaction tube.
By injecting gas while moving in the tube at an angle of 30 ° to 30 °, the method of supplying gas onto the wafer 14 mounted on the susceptor 9 is improved, and the film thickness to be formed is uniform. It is characterized by trying to improve the sex.

[0007]

In the above-mentioned conventional horizontal reactor, the gas supply pipe having the gas injection port is moved while being rotated to supply the gas to make the film thickness uniform.
The gas injection direction must be changed even by the growth film and the diffusion of impurities, which has a drawback of extremely poor operability. Further, there is also a drawback that the equipment cost becomes high because a mechanism for moving the gas supply pipe into the pipe is required. further,
There is a problem in that the mechanism that swirls while moving acts as a dust source and causes a serious defect in the quality that contaminates the film formation of the wafer.

Therefore, an object of the present invention is to provide a horizontal reactor capable of uniformly treating the surface of a wafer without requiring a complicated movable mechanism which is a dust source.

[0009]

A feature of the present invention is that the semiconductor substrate is inserted into a laterally elongated furnace core tube and heated at a high temperature, and the semiconductor substrate is oxidized / diffused or polycrystallized under an atmosphere of a reaction gas. In a horizontal reactor for depositing a silicon film, a nitride film, etc., a gas supply mechanism arranged in the upper part of the furnace core tube and having a plurality of gas outlets for introducing the reaction gas arranged side by side in the lateral direction. And a gas discharge pipe having a gas exhaust port that is disposed in the lower part of the furnace core tube so as to face the gas outlet port and that exhausts the reaction gas. Further, it is preferable that the gas supply mechanism includes a plurality of gas introduction pipes having one of the gas outlets.

[0010]

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

1A and 1B are a schematic vertical sectional view and a schematic horizontal sectional view, respectively, showing a horizontal reactor in one embodiment of the present invention. This horizontal reactor is, as shown in FIG. 1, arranged in the upper part of the furnace core tube 6 and has gas outlets 3a, 3b, 3c for introducing the reaction gas.
A plurality of gas supply mechanisms 1 arranged side by side in the lateral direction,
The gas discharge pipe 2 is provided in the lower part of the furnace core tube so as to face the gas outlets 3a, 3b, 3c and has a gas exhaust port 4 for exhausting the reaction gas. Other than that, it is the same as the conventional horizontal reactor described in FIG.

The gas supply mechanism 1 includes a plurality of gas introduction pipes 1.
a, 1b, 1c, and gas outlets 3a, 3
Flow rate valves (not shown) are independently provided in the respective gas introduction pipes 1a, 1b, 1c so that the flow rates of the reaction gases in b, 3c become constant. The gas outlets 3a, 3b, 3c are arranged at equal intervals in the longitudinal direction so that the gas is uniformly supplied to the wafers 14 placed side by side on the boat 5.

On the other hand, at the lower part of the furnace core tube 6, the gas exhaust port 4 is provided so as to face the gas outlets 3a, 3b and 3c.
A gas exhaust pipe 2 having the above is arranged. The reaction gas is made to flow uniformly in a laminar flow state between the wafers 14 of the boat 5, and a fresh reaction gas having a large concentration of active molecules and having a uniform concentration is constantly brought into contact with the wafer 14. In order to make the flow more uniform, the gas discharge pipe 2 is made into a branch pipe having each exhaust port 4 independently, and a control valve capable of adjusting exhaust resistance is provided in each of these branched pipes. It may be adjusted to make the flow between the wafers 14 uniform.

Next, the operation procedure of this horizontal reactor will be described. First, the door 7 is opened, and the quartz boat 5 loaded with the wafers 14 in the furnace core tube 6 heated at high temperature is inserted. Next, the door 7 is closed, and the gas outlets 3a, 3b, 3c of the gas introduction pipes 1a, 1b, 1c provided on the upper part of the furnace core pipe 6 are closed.
While introducing a more desired gas (oxygen, nitrogen, etc.), the reaction gas introduced through the gas exhaust port 4 of the gas exhaust pipe 4 is exhausted. As a result, the wafer 14 is always in contact with the reaction gas having a constant concentration, and the surface of the wafer 14 can be oxidized or the film can be grown.

Here, in the drawing, three exhaust ports 4 are shown facing the gas outlets in the upper part of the furnace core tube 6, but three or more exhaust ports 4 may be provided as long as the arrangement is permitted. As a result, the reaction gas smoothly flows in the longitudinal direction of the furnace core tube 6 in a laminar flow state from the upper part of the furnace core tube to all the wafers 14
However, the gas can be uniformly supplied. As a result, the concentration of the gas involved in the reaction can be made uniform in the furnace core tube 6, and the in-batch uniformity and the in-plane uniformity of the film that is oxidized or grown on the semiconductor substrate inserted in the furnace core tube. Can be improved.

Further, the gas introduction pipes 1a, 1b, 1c provided on the upper part of the furnace core tube are arranged as long as the arrangement is allowed in order to further equalize the amount of gas blown out in the back, center and front side of the furnace. As with the above-described exhaust port 4, it is preferable to have three or more blowout ports at the back, center, and front of the furnace.

[0017]

As described above, the present invention is provided with a plurality of gas outlets for ejecting a reaction gas over the row of a plurality of wafers arranged on the upper part of the furnace core tube.
A plurality of exhaust ports are provided in the lower part of the furnace core tube facing the blowout port, and the reaction gas flows from the upper side to the lower side in a laminar flow state, so that each of the wafers comes into contact with the reaction gas having a uniform concentration. However, there is an effect that the surface treatment of the wafer can be made uniform.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view and a schematic horizontal sectional view showing a horizontal reactor according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a conventional horizontal reactor.

FIG. 3 is a longitudinal sectional view and a lateral sectional view showing another example of a conventional horizontal reactor.

[Explanation of symbols]

 1 gas supply mechanism 1a, 1b, 1c gas introduction pipe 2 gas discharge pipes 3a, 3b, 3c gas outlet 4 gas exhaust 5,13 boat 6,11 furnace core pipe 7 door 10 gas supply pipe 11a reaction pipe 12 heater 14 Wafer

Claims (2)

[Claims] 1. A semiconductor substrate is subjected to an oxidation / diffusion process or a polycrystalline silicon film, a nitride film or the like is formed under a reaction gas atmosphere while being inserted into a furnace core tube that is long in the lateral direction and heated at a high temperature. In a horizontal reactor, a gas supply mechanism arranged in an upper part in the furnace core tube and a plurality of gas outlets for introducing the reaction gas arranged side by side in a lateral direction, and a gas supply mechanism arranged in a lower part in the furnace core tube. A horizontal reaction apparatus, comprising: a gas exhaust pipe, which is provided so as to face a gas outlet and has a gas exhaust port for exhausting the reaction gas. 2. The horizontal reactor according to claim 1, wherein the gas supply mechanism includes a plurality of gas introduction pipes each having one of the gas outlets.