JPH02128419A - Semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To prevent the oxidation of Si wafers from occurring by a method wherein N2 gas or an inert gas is led in from the lower part of a carrying in and out port or the wafers. CONSTITUTION:The gas inside a diffusion furnace heated and density-reduced in case of carrying in and out Si wafers 2 runs out of the upper part of the carrying in and out port 5. At this time, the part near the port 5 of Si wafers 2 of the diffusion furnace can be constantly kept out of the atmosphere by letting N2 gas (c) (carrier gas) or an inert gas (d) run out of the lower gas leading-in port 8 externally. However, the leading-in gas at this time is not directly jetted but the diffusion furnace is filled up with the N2 gas or the inert gas to prevent the thermal oxidation in the process of temperature decline in case of taking out Si wafers 2 from occurring. Through these procedures, a silicon dioxide film in even film thickness and film quality can be formed in the oxidation diffusion process.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to semiconductor manufacturing equipment, and in particular to the structure of a horizontal thermal oxidation diffusion furnace (hereinafter referred to as a diffusion furnace) used in a diffusion treatment process. .

[Conventional technology]

FIG. 3 is a schematic sectional view showing a diffusion furnace used in a conventional diffusion treatment process, and FIG. 4 is a schematic partial sectional view illustrating the flow of carrier gas and atmosphere in the diffusion furnace of FIG. 3. In Figure 0, a quartz boat (1) is placed in the diffusion furnace, and a Si wafer (2) is placed on top of the quartz boat (1). Around the quartz tube (3) there is a heater (4) along the outer periphery.
The structure is such that the entire diffusion furnace is kept at a high temperature. In general, the material gas is transported to the Si Uni-Hachi 2) at the entrance (5).
) is introduced from the gas inlet (7) on the opposite side. Further, an exhaust port (6) is provided for exhausting this material gas.

Next, a general thermal oxidation process for the S1 wafer (2) will be explained. For example, if thermal oxidation at 900'c is required,
Eli wafers (2) are arranged on a quartz boat (1),
Installed in a diffusion furnace. At this time, N2 gas is introduced through the gas inlet (7) for the purpose of eliminating the influence of O2 in the diffusion furnace. After the quartz boat (1) reaches the predetermined position,
Desired 02 gas is introduced through the gas inlet (7).

When the treatment is completed, N2 gas is introduced again and the quartz bowl 1 is removed.
(1) is extracted and the process is completed.

[Problem to be solved by the invention]

Since the conventional diffusion furnace was configured as described above, there were the following problems in the heat treatment process.

When the S1 wafer is carried in and out from the carry-in/out port, the carrier gas that continues to flow has a reduced density because it is heated by the heater, and flows out from above the carry-in/out port as shown in FIG. Therefore, air enters the vicinity of the loading/unloading entrance of the diffusion furnace from below. As a result, the lower part of the S1 wafer near the loading/unloading entrance is heated by the diffusion furnace and is exposed to the atmosphere, so it is thermally oxidized.

This invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor manufacturing apparatus that prevents thermal oxidation of the lower part of the S1 wafer when the S1 wafer is carried out to a diffusion furnace. shall be.

[Failure to solve the problem]

In the diffusion furnace according to the present invention, a gas inlet is also provided below the carry-in/out port, and by introducing N2 gas or inert gas from the gas inlet, the atmosphere entering from below the carry-in/out port is removed when carrying in and out of Si wafers. Prevent direct light from shining on the S1 wafer.

[Effect]

Since the diffusion furnace of this invention introduces υN2 gas or inert gas through the gas inlet provided below the loading/unloading entrance,
When carrying the Si wafer into and out of the diffusion furnace, the Si wafer is not directly exposed to the atmosphere, thereby preventing oxidation of the S1 wafer.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the description of this embodiment, the description of parts that overlap with the description of the conventional technology will be omitted as appropriate.

Figure 1 is a schematic sectional view showing the structure of a diffusion furnace, and Figure 2 is a schematic cross-sectional view showing the structure of a diffusion furnace.
FIG. 2 is a schematic partial cross-sectional view illustrating the flow of gas such as carrier gas in the diffusion furnace shown in the figure. In the figure (1) to (7
) is equivalent to that shown in the conventional example of FIG. The configuration of the apparatus shown in Fig. 1 differs from the conventional diffusion furnace shown in Fig. 3 in that a gas inlet (8) is installed below the inside of the loading/unloading port (5) for the S1 wafer (1) of the diffusion furnace. That's true. Further, the gas inlet (8) is installed in a direction in which the introduced gas flows out to the outside so that the atmosphere does not enter into the diffusion furnace. The gas used here is N2 gas or inert gas, and when N2 gas is used, N2 gas for carrier gas is used.
It may also be a structure in which it is connected to.

Next, the operation will be explained.

When the S1 wafer (2) is carried in and out, the gas in the diffusion furnace is heated and its density is reduced, so that it flows out to the upper part of the carry-in/out entrance (5) as shown in FIG. Therefore, by flowing N2 gas or inert gas from the lower part of the interior near the loading/unloading port (5) of the diffusion furnace through the lower gas inlet (8), the S1 wafer (2) can always be unloaded from the diffusion furnace. It becomes possible to prevent the vicinity of the entrance (5) from being exposed to the atmosphere (02). However, the introduced gas at this time is not directly sprayed onto the S1 wafer (2), but by filling the inside of the diffusion furnace with N2 gas or inert gas, the Si wafer (2) is
The purpose is to prevent thermal oxidation of the S1 wafer (2) during the temperature cooling process during unloading.

〔Effect of the invention〕

As described above, according to the present invention, the S1 wafer is often exposed to the atmosphere immediately before being transferred to the Si urchin, and thermal oxidation is prevented even if the S1 wafer is heated at the loading/unloading entrance of the diffusion furnace. Therefore, a silicon dioxide film with uniform thickness and quality can be obtained in the oxidation diffusion process.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a diffusion furnace according to an embodiment of the semiconductor manufacturing apparatus according to the present invention, and FIG. 2 is a schematic section illustrating the flow of gas such as carrier gas in the diffusion furnace of FIG. 1. 3 is a schematic sectional view showing the structure of a conventional diffusion furnace, and FIG. 4 is a schematic partial sectional view illustrating the flow of carrier gas and atmosphere in the diffusion furnace of FIG. (8) is a gas inlet. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A semiconductor manufacturing apparatus characterized in that, in a horizontal thermal oxidation diffusion furnace, at least one N2 gas or inert gas inlet is installed near the S1 wafer loading/unloading port.