JPS6218039A - Oxidizing device for semiconductor wafer - Google Patents

Abstract

PURPOSE:To heat uniformly semiconductor wafers, and to form uniform oxide films by a method wherein a reaction vessel is separated to a hydrogen combustion part and a reaction part, and a partition having a path is arranged between them. CONSTITUTION:A partition 19 manufactured of quartz and to separate the inside of a reaction tube 11 to a combustion part 11a and a reaction part 11b is provided, and the combustion part and the reaction part are interconnected through a path 19a opened in the partition 19. When the partition 9 like this is provided, an invasion of flame to be generated when hydrogen gas supplied from a cylinder 17 through a pipe 16 is burned in the combustion part 11a to the reaction part 11b is checked. Moreover, because heat to be generated by combustion of hydrogen is also shielded by the partition 19, heat is not almost transmitted to the reaction part 11b, and semiconductor wafers 13 accommodated in the reaction part are heated uniformly according to a heater 18. While clean steam generated according to combustion of hydrogen is sent to the reaction part 11b through the path 19a, and reacts with the semiconductor wafers 13 to form uniform oxide films.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a technology for manufacturing semiconductor devices, and more particularly to an improvement in an apparatus for performing wet oxidation on a half-quad wafer.

(Prior Art) Recent technological innovations in VLSI have been remarkable, and supporting technologies include microfabrication technology, diffusion technology, oxidation technology, and ion implantation technology. Especially memory LS
In I, an extremely thin gate oxide film and a high quality oxide film are required.

Hydrogen combustion oxidation technology has been developed as a method for forming high-quality oxide films. In this method, hydrogen gas and oxygen gas are supplied to a reaction tube for reaction combustion, and the water vapor generated at this time forms a film of, for example, a Sin film on the surface of a silicon wafer. This method is now widely used because it can prevent contamination caused by bacteria, line piping, or water exchange compared to the method of generating water vapor.

FIG. 3 shows the configuration of a conventional wet oxidation apparatus, in which a large number of semiconductor wafers 3 placed almost vertically on ports 2 also made of quartz are housed inside a reaction tube 1 made of quartz. . A pipe 4 is provided on one side of the reaction tube 1, which is connected via a valve to a cylinder 5 filled with oxygen gas, and a pipe 6 is provided, which is connected via a valve to a cylinder 7 filled with hydrogen gas. . Furthermore, a heater 8 is wrapped around the outer periphery of the reaction tube 1.

First, the semiconductor wafer 3 is mounted on the boat 2, and the boat is inserted into the reaction tube 1. After that, oxygen gas is supplied from the cylinder 5 through the pipe 4 into the reaction tube, and the heater 8 is energized to heat it. When the temperature of the semiconductor wafer 3 becomes equal to the temperature of the reaction tube 1, hydrogen gas is supplied from the cylinder 7 to the reaction tube 1 through the vibro. This hydrogen gas mixes with oxygen and burns at the exit of the vibro, producing water vapor. The water vapor thus generated can act on the semiconductor wafer in a high temperature state to cause an oxidation reaction and form an oxide film.

(Problems to be Solved by the Invention) According to the conventional oxidizer described above, when hydrogen reacts with oxygen and burns, a flame is generated, which spreads inside the reaction tube, resulting in an increase in the temperature of the surrounding area. .

Therefore, the temperature of the semiconductor wafer near the side where the pipe 4.6 of the reaction tube is installed becomes locally high, and as a result, the oxide film is not formed uniformly on all the semiconductor wafers, which has an extremely negative effect on the device characteristics. There are drawbacks to giving. In the conventional oxidation apparatus shown in FIG. 3, the vibro which spews out hydrogen gas is made into a U-shape so that the flame generated during hydrogen combustion does not directly affect the semiconductor wafer 3, and the hydrogen gas is jetted on the opposite side from the semiconductor wafer. I try to do that. However, since there is no partition between the area where hydrogen gas is burned and the area where the semiconductor wafers are stored, it is inevitable that the flames generated by the combustion will reach the semiconductor wafers, and the flames generated by the combustion will inevitably reach the semiconductor wafers. The heat generated is transferred to the semiconductor wafer, and the temperature of the semiconductor wafer near the combustion zone is higher than the temperature of the semiconductor wafer on the opposite side. According to the inventor's experiments, it was confirmed that the semiconductor wafers on both sides had a temperature difference of about 10°C.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an oxidation apparatus that can maintain a uniform temperature of a semiconductor wafer housed in a reaction tube, and thus can form a uniform oxide film. The purpose is to

(Means for Solving the Problems) The oxidation apparatus of the present invention includes a reaction container for storing a semiconductor wafer on which an oxide film is to be formed, a means for supplying hydrogen gas and oxygen gas to the reaction container, and a reaction container. The combustion section that burns the hydrogen gas supplied to the interior of the combustion chamber and the reaction section that causes the water vapor generated by combustion to act on the semiconductor wafer to perform an oxidation reaction are separated, and a passage connects them to generate the oxidation reaction in the combustion section. It is characterized by comprising a partition wall that prevents heat from being transferred to the reaction section.

(Function) According to the oxidation apparatus of the present invention described above, since the hydrogen combustion section and the reaction section are separated by the partition wall, the flame generated by hydrogen combustion does not enter the reaction section, and the combustion It also effectively prevents the generated heat from being transferred to the semiconductor wafers, making it possible to form an oxide film with uniform dimensions and properties on all semiconductor wafers, which is similar to dry oxidation. An oxide film is obtained.

(Embodiment) FIG. 1 shows the structure of an embodiment of an oxidation apparatus according to the present invention. A semiconductor wafer 13 placed on a quartz boat 12 is inserted into a quartz reaction tube 11, and oxygen gas is supplied from a cylinder 15 through a pipe 14, and hydrogen gas is supplied from a cylinder 17 through a pipe 16. The configuration in which the heater 18 is wound around the outer periphery of the reaction tube 11 is the same as that of the conventional device. In the present invention, a partition wall 19 made of quartz is provided to separate the inside of the reaction tube 11 into a combustion section 11a and a reaction section 11b.
The two are communicated through a passage 19a opened in the two. By providing such a partition wall 19, the flame generated when the hydrogen gas supplied from the cylinder 17 through the pipe 16 is combusted in the combustion section 11a will not enter the reaction section 11b. Furthermore, since the heat generated by the combustion of hydrogen is also shielded by the partition wall 19, almost no heat is transmitted to the reaction section 11b, and the semiconductor wafer 13 housed in the reaction section is uniformly heated by the heater 18. On the other hand, clean water vapor generated by hydrogen combustion is sent to the reaction section 11b through the passage 19a, and reacts with the semiconductor wafer 13 to form a uniform oxide film.

As described above, according to the oxidation apparatus of the present invention, the flame and heat generated by hydrogen combustion can be effectively prevented from acting on the semiconductor wafer by the partition wall 19, and therefore the temperature of the semiconductor wafer becomes uniform. A uniform, high-quality oxide film can be formed with high precision, and it is also possible to control oxidation on a submicron level.

The present invention is not limited to the embodiments described above, but can be modified in many ways. For example, the shape of the partition wall 19 is
In addition to the above-mentioned arrangement, the passage 19a may be vertical as shown in FIG. 2, and the passage 19a may protrude toward the combustion section 11a.

Further, the number of passages does not necessarily have to be one, and two or more passages can also be provided. Further, in the above embodiment, hydrogen gas and oxygen gas are supplied to the reaction tube, but in addition to these gases, an inert gas such as nitrogen gas may also be supplied. Further, the reaction container does not necessarily have to be a cylindrical reaction tube, and can have various shapes.

(Effects of the Invention) According to the oxidation apparatus of the present invention, the reaction vessel is separated into a hydrogen combustion section and a reaction section, and a partition wall having a passage is arranged between these sections, so that the flame of hydrogen combustion is transmitted to the reaction section. Since the heat generated by combustion does not reach the reaction area, the semiconductor wafer is heated uniformly, and a uniform oxide film can be formed on all semiconductor wafers. The oxidation treatment in the manufacturing process can be performed with high precision, and the yield can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an embodiment of the oxidizing device according to the present invention, FIG. 2 is a cross-sectional view showing the structure of a modified example thereof, and FIG. 3 is a cross-sectional view showing the structure of a conventional oxidizing device. be. 11... Reaction tube 11a... Combustion section 11
b...Reaction section 12...Boat 13...
Semiconductor wafer 14.16... Pipes 15, 17
...Cylinder 18...Heater 19...Bulkhead 19a...When in passage Applicant
TDC Co., Ltd. Figure 1

Claims (1)

[Claims] 1. A reaction vessel for storing a semiconductor wafer on which an oxide film is to be formed, a means for supplying hydrogen gas and oxidizing gas to the reaction vessel, a combustion section for burning the hydrogen gas supplied into the reaction vessel, and a combustion A partition wall that isolates a reaction section in which generated water vapor acts on the semiconductor wafer to perform an oxidation reaction, and connects them with a passage to prevent heat generated in the combustion section from being transmitted to the reaction section. A semiconductor wafer oxidation apparatus comprising: