JPS60154489A - Light emission furnace - 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 is applicable to light irradiation furnaces, especially heat treatment in which rapid heating and rapid cooling can be operated safely and reliably in oxygen/hydrogen combustion atmosphere heat treatment furnaces. Regarding furnaces.

(Prior Art) As semiconductor technology advances, semiconductor elements have been miniaturized, the depth of impurity diffusion junctions has become shallower, and the heat treatment process in the semiconductor device manufacturing process has inevitably been shortened.

A light irradiation heating furnace using a nitrogen lamp or the like is known as an effective method for shortening the thermal process. However, light irradiation heating furnaces designed according to the prior art.

The method is such that the gas is introduced directly into the heating area of the substrate.

In conventional furnaces, nitrogen, oxygen, air, or the like is mainly used as the substrate heat treatment atmosphere.

Therefore, it is effective for processes that are processed in nitrogen, such as the activation process of impurities ion-implanted into a semiconductor substrate. However, processes using an oxygen/hydrogen combustion atmosphere, such as silicon substrate oxidation, have extremely serious problems in terms of safety and process stability, and are virtually impossible to apply.

That is, when using a prior art furnace, the interior of the furnace must be sufficiently heated to prevent ignition from occurring before the hydrogen gas is directly introduced into the substrate heating area.

Furthermore, after the bulk ignition of water, it takes some time until the inside of the furnace is sufficiently filled with steam. Further, even after the oxidation is completed, the high temperature must be maintained until the hydrogen gas in the piping is sufficiently purged. Therefore, in the prior art furnace, a high temperature holding time of several tens of seconds is required in addition to the actual oxidation. This means that the loss time is extremely long in the light irradiation heating oxidation process where the actual oxidation time is assumed to be several tens of seconds or less.

Furthermore, if hydrogen gas is supplied at a low temperature (lower than the furnace ignition temperature) due to equipment failure, an explosion may occur during the subsequent light irradiation process, leading to a serious accident. From the standpoint of safety, it must be said that it is extremely inappropriate to use the prior art furnace as an oxy-hydrogen combustion furnace.

It is also possible to create a water vapor atmosphere by heating and evaporating pure water, but in this case, impurities in the pure water are introduced into the atmosphere, which is not suitable for many years. I don't get it.

(Object of the Invention) The object of the present invention is to eliminate such drawbacks and to provide a light irradiation heating furnace which allows safe and reliable oxidation in an oxygen/hydrogen combustion atmosphere and can be performed in a short time.

(Structure and operation of the invention) The present invention provides a preheating furnace for ignition of oxygen and hydrogen in addition to the main body of the photocopying furnace, and introduces oxygen gas or hydrogen gas into the preheating furnace to perform one ignition. By doing this reliably, you can prevent accidents caused by misfires even in light irradiation furnaces using halogen lamps, etc., and safely remove oxygen Φ.
This is based on the knowledge that hydrogen combustion atmosphere oxidation becomes possible.

(Effects of the Invention) By using the present invention, oxidation in an oxygen/hydrogen combustion atmosphere can be easily put into practical use in a sufficiently short period of time. Moreover, the high-quality gate insulating film is reproducible.

It has great effects, such as the ability to easily form advanced field effect transistors using highly transparent 7-T insulating films that can be realized with high reliability.

(Example) Next, the present invention will be explained based on two examples. Fig. 1 is a detailed explanatory diagram of the present invention. A core tube 2 made of quartz is installed in a housing 1 of this device. (Gas inlet 3)
Hydrogen gas and nitrogen gas are introduced, and υoxygen gas is introduced through the gas inlet 4.

The semiconductor substrate 5 is placed on a support base 6 made of quartz, and heating is performed mainly using a group of halogen lamps 7. This device is equipped with a reflector plate 8 to increase light irradiation efficiency, and is provided with a preheating chamber 9, which uses a resistance heater 1O to heat the temperature above the oxygen or hydrogen ignition temperature. It is preserved.

The temperature of the preheating chamber is constantly monitored by a thermocouple 11, and a safety circuit is built in to automatically stop the supply of hydrogen if the temperature drops below the ignition temperature.

When the apparatus of this embodiment is used, hydrogen is always ignited in the preheating chamber 9. Therefore, the inside of the furnace can be filled with an oxygen/hydrogen combustion atmosphere in a relationship with the output of the halogen lamp 7 or the temperature inside the furnace. Temporarily.

Even in the event of a misfire due to poor contact with the halogen lamp at the start of hydrogen supply, which could lead to a major accident in a conventional furnace, the oxygen and hydrogen are reliably ignited in the preheating chamber. The safety of the equipment is ensured.

The heating program using the halogen lamp and the steaming program for the atmosphere inside the furnace can be programmed completely independently. It is also possible to create an oxygen/hydrogen combustion atmosphere in the furnace in advance, and then perform rapid heating and cooling using the halogen lamp 7. The process of forming a gate insulating film for an effect type element is effective. The gate oxide film is formed by directly oxidizing the silicon substrate.
With the advancement of devices, the film thickness has been reduced to 20 nm.
The following thin films have also been requested. Generally, silicon oxide films formed in an oxygen-hydrogen combustion atmosphere have fewer defects and are of better quality than those formed in a dry oxygen atmosphere. Further, as the oxidation temperature, it may be desirable to form the film at a high temperature of about 1000°C. At such high temperatures, the rate of oxide film formation is extremely rapid, making it impossible to form such thin films in prior art furnaces.

However, if the apparatus of this embodiment is used, high-temperature short-time oxidation of the thigh for a few seconds is easily possible, and a thin film with a thickness of L20 nm or less can be easily realized. Field effect devices can also be manufactured easily.

This equipment is used not only for the gate insulating film formation process.

It goes without saying that the present invention can be applied to other oxidation processes or non-oxidation processes.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention.
Housing, 2... Quartz furnace tube, 3... and 4...
...Gas inlet, 5...Semiconductor substrate, 6
...Support stand, 7...Halogen lamp%
8...Reflector, 9...Preheating chamber,
10...Heater, 11...Represents a thermocouple.

Claims (1)

[Claims] In a heat treatment furnace that mainly uses light irradiation, at least a part of the combustion-supporting gas and the combustible exhaust gas introduced into the heat treatment furnace are
A light irradiation furnace characterized by having a structure in which the light irradiation furnace passes through a preheating chamber in advance.