JPS60193343A - Heat treatment device - Google Patents

Abstract

PURPOSE:To enable to control the cooling speed of a substance to be irradiated by infrared rays independent of heat capacity of a heat treatment device by a method wherein cooling gas is introduced to the substance to be irradiated. CONSTITUTION:Infrared beams 3 radiated from halogen lamps 1 are projected to a sample 5 to be irradiated passing in a furnace tube 4 directly or through reflectors 2. Inactive gas or reducing gas 7 is flowed in the furnace tube 4 during the sample 5 is heat-treated. After the sample is held at the heat treatment temperature for the prescribed hours in such a way, the gas 7 is changed at once over cooling gas, nitrogen gas generated from liquid nitrogen for example. Or cooling gas is mixed to the gas 7. Accordingly, the desired temperature descending speed can be obtained.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a heat treatment apparatus.

[Prior art and its problems]

In the semiconductor device manufacturing process, activation of implanted impurities and alloying of ohmic contact metals.

A heat treatment process is essential for metal wiring sinks, etc. With the miniaturization and higher performance of devices, it has become necessary to perform heat treatment in a short period of time in a transient state. For example, when activating an ion-implanted layer, it is desirable to maintain the impurity distribution during implantation as much as possible in order to satisfy device design standards. Alternatively, when an ohmic contact is formed by alloying metals, the rate at which the temperature is raised to the alloying temperature and the rate at which the temperature is lowered affects the properties and contact resistance of the ohmic contact.

Under these circumstances, laser annealing or electron beam annealing methods have been developed.1 For example, laser annealing cannot uniformly irradiate within a wafer, leading to non-uniform properties, or electron beam annealing However, problems such as low carrier mobility within the active layer have arisen, so that it has not been put to practical use at present.

On the other hand, heat treatment furnaces that use infrared rays or other light beams can achieve superior uniformity within the wafer compared to the above-mentioned methods that use lasers or electron beams, or that the heating rate is higher than that of both of these methods and electricity. It is located in the middle of the furnace, and has the advantages of being able to rapidly heat the semiconductor substrate to an extent that does not cause plastic deformation due to thermal strain, and that the device is easy to handle.

However, the object to be irradiated is placed in the irradiation area of the light beam.

If the furnace is left until it cools down after irradiation, the cooling rate of the irradiated object depends on the heat capacity of the entire furnace, so the first
As shown in the figure, only a limited cooling rate can be obtained, and therefore, the expansion of the implanted layer in the above example cannot be sufficiently suppressed, or the alloying of the ohmic contact takes a long time. .

[Purpose of the invention]

This invention aims to solve the above-mentioned problems.

An object of the present invention is to provide a heat treatment device that can control the cooling rate.

[Summary of the invention]

The present invention introduces a cooling gas into the object to be irradiated.
The cooling rate of the irradiated object can be adjusted independently of the heat capacity of the heat treatment equipment. [Effects of the Invention] By using the heat treatment equipment according to the present invention, high-output incoherent light can be irradiated in a short time. For example, when used for activating an ion-implanted layer of a semiconductor, a heat treatment is performed, followed immediately by a desired temperature drop.
Redistribution of implanted impurities can be prevented by quickly lowering the temperature after reaching the processing temperature at a rapid temperature increase rate of 00° C./sec. Or 1 for example Au-
(g) When obtaining ohmic contact by alloying a metal of the Ga-containing S crystal with a Ga-containing S crystal, the heating and cooling, which affect the characteristics, are carried out quickly, making it possible to obtain a uniform alloy layer with low contact. You can get the resistance value.

Furthermore, when a Schittky junction is formed by combining a compound such as WN with GaAs, a steep Schittky barrier can be realized (because the original temperature rise/fall rate is fast).

[Embodiments of the invention]

The heat treatment apparatus of the present invention will be explained below using one drawing. FIG. 1 is a diagram showing the basic configuration of the heat treatment apparatus of the present invention. For example, an infrared beam 2 emitted from a halogen lamp 1 is transmitted directly or through a reflection process 3 to a material such as quartz, which has a low absorption coefficient for infrared rays. A sample 5 to be irradiated placed inside the tube is irradiated through a furnace tube 4 made of the same material. The sample 5 to be irradiated is placed on a sample stage 6 made of a material with low absorption of infrared rays, like the furnace tube 4 . When heat-treating the sample 5, a reducing gas 7 such as an inert gas or hydrogen gas is often flowed into the furnace tube 4 to prevent chemical reactions such as oxidation of the sample 5. Cooling water or the like 9 is poured onto the support stand 8 constituting the device 3 in order to prevent the device from overheating.

Figure 2 shows sample 5 when using the heat treatment equipment shown in Figure 1.
This is an example of a temperature profile recorded with a thermocouple attached to a As an example of sample 5.

Implanted Ueno 1, in which silicon ions were implanted into a GaA crystal, was used. Minimize changes in implanted impurity profile
%, it is necessary to raise the temperature sharply (there is some force).In order to easily raise the temperature, the temperature is raised from room temperature to ℃ for about 100 seconds and maintained.

Next, with a temperature gradient of about 100°C/sec, from 100°C to 9
After raising the temperature to 50°C and keeping it at this temperature for a few seconds, the lamp input is turned off and the temperature is allowed to drop. At this time, the rate of temperature decrease depends on the heat capacity of the heat treatment furnace.

As mentioned above, it is desirable to maintain the profile of the injection layer as much as possible during injection.

Therefore, in addition to temperature increase, the rate of temperature decrease is also important from the standpoint of minimizing re-diffusion of impurities. In the heat treatment apparatus shown in FIG. 1, the rate of temperature drop depends on the rate at which the applied output is absorbed by the cooling water or the surrounding air after infrared irradiation is stopped by turning off the lamp. Therefore, depending on the device, it is not possible to cool the temperature faster than a certain rate.

In the present invention, the heat treatment temperature is determined in consideration of this point.

Here, after maintaining the temperature at 900°C for a predetermined period of time, the gas shown in Figure 1 7 is immediately switched to a cooling gas, such as nitrogen gas from liquid nitrogen, or the cooling gas is mixed into the gas that is flowing first. By the way.

It is characterized by obtaining a desired temperature decreasing rate.

As a result, as shown by the broken line in FIG. 2, steep cooling that is almost the same as the temperature increase rate can be realized.

[Other embodiments of the invention]

In the above outline, the gas inflow direction is set parallel to the surface of the sample surface, but when considering uniformity within one surface of the ware, it is not limited to one direction but perpendicular to the drawing. Inflow from two directions (two directions), #! Exhaust gas 7 from the thread path (both inlet and outlet) shown in Figure 1. Alternatively, it is possible to consider a change in its existence, such as introducing gas from both the outlet and the inlet of the yarn path shown in FIG. 1 and exhausting it from two directions perpendicular to the drawing.

In addition to nitrogen from liquid nitrogen, the cooling gas may include helium from liquid helium, or a mixture of these and an inert gas.

[Brief explanation of drawings]

Figure 1 is Figure 1m showing the basic configuration of the heat treatment apparatus of the present invention.
FIG. 2 is a diagram comparing the temperature rise and temperature drop characteristics of the heat treatment apparatus of the present invention and the conventional heat treatment apparatus. 1...Halogen lamp, 2...Infrared beam, 3
...Reflector, 4. Furnace tube, 5. Irradiated sample, 6. Sample stage. 7...Gas, 8...Support stand. 9...Water. Agent: Patent attorney Kensuke Norichika (and one other person) Figure 1 Figure 2

Claims (1)

[Claims] A gas is introduced into the means for emitting light and the object to be irradiated. A heat treatment device characterized by being equipped with a cooling mechanism.