JPH01739A - Thermal oxidation equipment for semiconductor substrates - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor manufacturing apparatus, and particularly to a thermal oxidation apparatus for semiconductor substrates.

[Conventional technology]

A thermal oxidation device for semiconductor substrates is a device used for forming gate insulating films, etc. of MOS FETs, and is generally used for the second
The configuration is as shown in FIGS. (a) to (b).

To grow an oxide film using the thermal oxidation bag shown in FIG. 2(a), semiconductor substrates 204 are first placed vertically at predetermined intervals in a furnace tube 202 heated to a constant temperature by a heater 201. 203 and inject 0.0 from the gas inlet. Or H.

An oxide film is formed on the surface of the semiconductor substrate by injecting a reaction gas 206 such as the above, and leaving it for a certain period of time while adjusting the temperature and pressure.

After the reaction is completed, the reaction gas in the reactor core tube is replaced with an inert gas such as N1, and then the heater is stopped and the reactor is cooled.

As shown in FIG. 2(b), a slit perpendicular to the horizontal plane is provided on the semiconductor substrate 203.
can be fixed perpendicular to the horizontal plane.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional technology, it is difficult to maintain a constant vertical temperature distribution within the reactor core tube, and the temperature in the upper part tends to be high. Furthermore, when replacing the reactant gas with an inert gas such as Nj' at the end of the reaction, it is difficult to replace the reactant gas uniformly due to the difference in specific gravity of the gas, and the partial pressure of the reactant gas at the upper part of the reactor tube sometimes increases. It tends to be expensive. In the thermal oxidation process of semiconductor substrates, the higher the oxidation temperature and the higher the partial pressure of the reactant gas, the higher the oxidation rate, and as a result, the in-plane uniformity of the oxide film formed on the surface of the semiconductor substrate deteriorates. Let's take a look at the problem.

The present invention solves these problems in the conventional thermal oxidation process of semiconductor substrates, and its purpose is to form a more uniform oxide film on the surface of a semiconductor substrate. The present invention provides a thermal oxidation device for a substrate.

[Means for solving problems]

The thermal oxidation device for semiconductor substrates according to the present invention includes a furnace tube made of a heat-resistant material, a heater for heating the furnace tube, a boat having a function of fixing the semiconductor substrate in the furnace tube, etc. , the boat is provided with a slit (notch) making an angle other than 90 degrees with respect to the horizontal plane, and has a function of fixing the semiconductor substrate at an angle other than 00 degrees with respect to the horizontal plane.

〔Example〕

FIGS. 1(a) and 1(b) are diagrams showing a thermal oxidation apparatus for semiconductor substrates according to the present invention, in which the semiconductor substrate is fixed at an angle other than 90 degrees with respect to the horizontal plane by forming diagonal slits in the boat. Here is an example with the function added. Figure 1 (a
) is a view showing the whole boat, and FIG. 1(b) is an enlarged view of the boat.

As shown in (a), the basic t+W component line is the same as the conventional one, and the only difference is the angle of the slit on the boat as shown in (b). A semiconductor substrate is inserted into an obliquely formed slit to be fixed at an angle other than perpendicular to a horizontal plane, and an oxide film is then formed on the surface using the same method as in the conventional method. By fixing the semiconductor substrate diagonally to the horizontal plane and the reactor core tube, the vertical height within the reactor core tube is reduced, and oxidation is not performed in the upper and lower parts of the reactor core tube, and the central part (as viewed from the side) is reduced. It becomes possible to carry out oxidation using only the room.

In FIG. 1, the wafer is tilted so that the lower end approaches the gas injection port, but the same effect can be obtained even if the wafer is tilted so that the upper end approaches the gas injection port.

〔Effect of the invention〕

As described above, according to the present invention, by installing the semiconductor substrate diagonally within the reactor core tube (as viewed from the lateral direction), it is possible to form a thermal oxide film without using the vertical space within the reactor core tube. . As stated in [Problems to be Solved by the Invention], there are large variations in temperature and reactant gas partial pressure in the vertical direction inside the reactor tube, which deteriorates the in-plane uniformity of the thermal oxide film thickness. By using the thermal oxidation device for semiconductor substrates according to the invention, the semiconductor substrate can be thermally oxidized using only a space where the temperature and partial pressure of the reactant gas are more uniform than in conventional devices, thereby improving the oxide film thickness. Internal uniformity can be improved. As a result, it becomes possible to produce semiconductor devices of more uniform quality at a higher yield from the same half-quad substrate.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are diagrams showing a thermal oxidation apparatus for semiconductor substrates according to an embodiment of the present invention. FIGS. 2(a) and 2(b) are diagrams showing a conventional thermal oxidation apparatus for semiconductor substrates. 101.201...Heater 102.202...Furnace tube 103.203...Boat 104.204...Semiconductor substrate 105.205...Gas inlet 106.206...Reactant gas 107, ? 07... Slippery
To the above applicants: Seiko Epson Co., Ltd. agent, patent attorney Tsutomu Mogami, and one other person.
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Claims (1)

[Claims] In a semiconductor substrate oxidation device formed by a core tube made of a heat-resistant material, a heater for heating the core tube, a boat having a function of fixing a semiconductor substrate in the core tube, etc., the boat is provided at an angle other than 90 degrees with respect to a horizontal plane. A slit is provided, and the semiconductor substrate is separated from the horizontal plane by 90°.
A thermal oxidation device for a semiconductor substrate, characterized by having a function of fixing at an angle other than degrees.