JP3072659B2 - Semiconductor heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor heat treatment apparatus.

[0002]

2. Description of the Related Art When a compound semiconductor wafer containing a high dissociation pressure element such as GaAs or InP is exposed to a high temperature, As,
There is a problem that P and the like are dissociated, and the wafer surface is roughened to deteriorate the crystallinity. 2 to 4 show a conventional apparatus for suppressing such dissociation. In the heat treatment apparatus shown in FIG. 2, a high-dissociation pressure element element 12 such as As or P is accommodated in a thin tube 2 at a lower end of a cylindrical container 18 and a semiconductor wafer 10 is supported on an upper portion thereof.
After being evacuated and evacuated, the upper end is sealed.
The cylindrical container 18 is supported by the lower shaft 7 and heaters 13 and 14 are provided.
In a heating furnace consisting of Then, the high-dissociation pressure element simple substance 12 is heated by the heater 14 to maintain a predetermined vapor pressure,
The heat treatment is performed by heating the semiconductor wafer 10 with the heater 13.

[0003] In the heat treatment apparatus shown in FIG. 3, a semiconductor wafer 10 is fixedly accommodated in a support 11 in a cylindrical container 19, a lower end thereof is sealed with a lid 20, and the semiconductor wafer 10 is evacuated through a conduit 21 provided in the lid 20. After the semiconductor wafer 10 is heated to the heat treatment temperature by the heater 23, arsine gas (AsH ₃ ), phosphine gas (PH ₃ ), or the like containing a high dissociation pressure element is supplied through a conduit 22 provided in the lid 20. Heat treatment is performed while maintaining a predetermined vapor pressure. At this time, the gas leaks from the gap between the cover 20 and the sensor 24, so that the sensor 24 constantly measures and monitors the gas.

In the heat treatment apparatus shown in FIG. 4, a high-dissociation pressure element 12 such as As or P is accommodated in a small tube 2 at the lower end of a cylindrical container 1.
The semiconductor wafer 10 is fixed to the support 11 and accommodated in the upper part. The cylindrical container 18 is supported by the lower shaft 7 and the heater 1
It is arranged in a heating furnace composed of 3 and 14. After the inside of the cylindrical container 1 is evacuated, an inert gas is supplied, and the upper shaft 2 is evacuated.
The lid 19 supported by 1 is lowered and hermetically closed. that time,
The upper end 3 of the cylindrical container 1 has an inverted truncated cone shape, and receives and seals the truncated cone portion 20 of the lid 19. Thereafter, the high-dissociation element 12 is heated by the heater 14 to maintain a predetermined vapor pressure, and the semiconductor wafer 10 is heated by the heater 13 to perform heat treatment.

[0005]

In order to heat-treat a large semiconductor wafer, a large-diameter cylindrical container is required. However, it is difficult to vacuum seal the upper end of the large-diameter container with the heat treatment apparatus shown in FIG. Therefore, there is a limit in increasing the diameter. Further, in the heat treatment apparatus shown in FIG. 3 for supplying arsine gas and phosphine gas, since these gases are very toxic, a separate apparatus for treating the leak gas is required, and considerable cost for safety measures including the treatment is required. It takes. In the heat treatment apparatus of FIG. 4 as well, there is a risk that the high dissociation pressure element gas leaks from the joint with the lid and contaminates the environment, and the high dissociation pressure element may be desorbed from the semiconductor wafer surface due to the leak. . Therefore, the present invention is intended to solve the above-mentioned drawbacks, to prevent the leakage of the high dissociation pressure element gas, and to provide a heat treatment apparatus capable of performing heat treatment without desorbing the high dissociation pressure element from the semiconductor surface. It is.

[0006]

SUMMARY OF THE INVENTION The present invention provides a cylindrical container for accommodating a semiconductor and a processing gas material, a lid for covering an open end of the cylindrical container, and supporting the lid and / or the cylindrical container so as to be vertically movable. A semiconductor heat treatment apparatus including a shaft, a heater for heating a semiconductor and a processing gas raw material, a chamber for accommodating the shaft, a vacuum exhaust system connected to the chamber, and an inert gas supply system. In order to more completely prevent a high dissociation pressure element gas leak from the cylindrical container, the open end of the cylindrical container is formed in an inverted truncated cone shape, and the bottom of the lid is formed in a truncated cone shape in contact with the open end. In addition, it is preferable that the inner circumference of the lid is sized to be in contact with the outer circumference of the cylindrical container. In addition, it is preferable that a movable part is provided on the support shaft of the lid or the cylindrical container to enable correction of a slight axis deviation between the cylindrical container and the lid and an inclination of the cylindrical container.

[0007]

FIG. 1 is a sectional view of a semiconductor wafer heat treatment apparatus according to one embodiment of the present invention. A thin tube 2 is connected to the tip of a cylindrical container 1, an open end 3 is formed into an inverted truncated cone shape, a single element 12 of high dissociation pressure is accommodated in the thin tube 2, and a semiconductor wafer 10 is fixed to a support 11 above. To accommodate. It is also possible to heat-treat the semiconductor ingot by replacing the wafer support 11. The open end 3 of the cylindrical container 1 has an inverted truncated cone shape so that the truncated cone-shaped bottom 5 of the lid 4 can be received. The cylindrical container 1 is supported by a lower shaft 7 and has a heater 1
It is arranged in a chamber 15 provided with 3,14. On the other hand,
The lid 4 is provided with a cylindrical portion 6 so as to cover the upper part of the cylindrical container 1 and reduces exhaust gas reactance to suppress gas leakage. It is also possible to completely prevent gas leakage by bonding a glue film or the like to the gap between the lid 4 and the cylindrical container 1. The lid 4 can be moved up and down and rotated in the horizontal direction by the upper shaft 8 having the movable spring 9, so that the cylindrical container 1 and the lid 4 can be slightly misaligned or the cylindrical container 1 can be rotated.
This is useful for compensating for the inclination and ensuring the adhesion between the two. A conduit 16 for connecting to a vacuum exhaust system and a conduit 17 for supplying an inert gas are connected to the bottom of the chamber 15. The heat treatment apparatus of FIG.
Although the case where the vertical cylindrical container is used has been described, it is also possible to arrange the horizontal container. In that case, there is no need to be a movable spring attached to the upper shaft.

Next, a heat treatment procedure for a semiconductor wafer will be described. First, the high-dissociation element 12 and the semiconductor wafer 10 are accommodated in the cylindrical container 1, and the cylindrical container 1 is disposed in the chamber 15 with the lower shaft 7 and hermetically sealed. Next, the chamber 15
After evacuating the inside, the upper shaft 8 is lowered and the cylindrical container 1 is evacuated.
The bottom portion 5 of the frustum of the lid 4 is brought into contact with the open end 3 of the lid 4, and a load is applied to hermetically close the lid. After a predetermined pressure is maintained by introducing an inert gas into the chamber 15, the high-dissociation element element 12 and the semiconductor wafer 10 are heated by the heaters 14 and 13 and the high-dissociation pressure element gas is introduced into the chamber 15. A predetermined vapor pressure is maintained, and the semiconductor wafer 10 is maintained at a processing temperature. At this time, the gas leak can be prevented by setting the pressure of the inert gas in the chamber 15 higher than the vapor pressure of the high dissociation pressure element gas in the cylindrical container 1. When the heat treatment under the high dissociation pressure element gas is completed, the heaters 13 and 14 are stopped and cooled, the cylindrical container 1 and the lid 4 are separated, the chamber 15 is evacuated once, and then inert gas is used. After returning the inside of the chamber 15 to the atmospheric pressure, the chamber 15 is opened and the semiconductor wafer is taken out.

As described above, the heat treatment apparatus of the present invention
There is no need to vacuum seal the container, which facilitates the use of large-diameter containers. Since the sealing of the container is performed after the entire chamber is evacuated, the same effect as the vacuum sealing can be expected. Further, since it is not necessary to use highly toxic gas such as arsine gas or phosphine gas, the equipment required for safety measures can be greatly reduced. Further, by making the inert gas pressure in the chamber higher than the vapor pressure of the high dissociation pressure element gas in the container, the leakage of the high dissociation pressure element gas can be easily prevented. Furthermore, by making the structure of the container and the lid as described above,
Gas leakage can be more reliably prevented. On the other hand, the prevention of gas leak leads to the maintenance of the high dissociation pressure element gas pressure in the container, and the desorption of the high dissociation pressure element from the semiconductor crystal surface can be suppressed.

[0010]

EXAMPLE A GaAs 4-inch wafer was heat-treated in the heat treatment apparatus shown in FIG. First, metal As is put into a thin tube of a container, the above-mentioned wafer polished to a mirror state is set on a flat-type support made of carbon, and a silica film is bonded to a joint between the container and the lid. After being housed in a container and placing the container in the chamber, the entire chamber was evacuated to about 2.7 × 10 ⁻⁴ Pa. Next, the lower shaft was driven to bring the lid into contact, and a load was applied to the upper shaft to bring them into close contact. Thereafter, a nitrogen gas was applied to the chamber at several atm or more, and then the temperature of the wafer portion was raised to 1200 ° C. just below the melting point of GaAs, and the temperature of metal As in a thin tube to 610 ° C., and the wafer was annealed for 8 hours. Thereafter, the heater is cooled to room temperature at a rate of about 5 ° C. per minute, the pressure in the chamber is evacuated again to about 2.7 × 10 ⁻⁴ Pa, the lid is opened to return to atmospheric pressure, and the wafer is taken out. When the surface was observed, A
No trace of desorption of s was observed, confirming that it was the same as in the case of vacuum sealing. In addition, the InP powder was introduced into the thin tube, and the thin tube portion and the wafer portion were set to the same temperature and time change, and
When the nP wafer was heat-treated, the same effect as above was confirmed.

[0011]

According to the present invention, by adopting the above-described structure, even a large-diameter semiconductor crystal can be easily heat-treated without causing gas leak, and the high dissociation pressure element from the semiconductor crystal surface can be removed. Desorption can be reliably suppressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat treatment apparatus as one specific example of the present invention.

FIG. 2 is a cross-sectional view of a conventional vacuum sealing type heat treatment apparatus.

FIG. 3 is a cross-sectional view of a conventional atmospheric gas supply type heat treatment apparatus.

FIG. 4 is a cross-sectional view of a conventional heat treatment apparatus using a lidded container.

Claims (3)

(57) [Claims] 1. A cylindrical container accommodating a semiconductor and a processing gas raw material, a lid covering an opening of the cylindrical container, a shaft supporting the lid and / or the cylindrical container so as to be able to move up and down, respectively, a semiconductor and a processing gas raw material. A semiconductor heat treatment apparatus comprising: a heater for heating; a chamber for accommodating the heater; a vacuum exhaust system connected to the chamber; and an inert gas supply system. 2. An opening end of the cylindrical container is formed in an inverted truncated cone shape, a bottom portion of the lid is formed in a truncated cone shape in contact with the opening end, and an inner periphery of the lid contacts an outer periphery of the cylindrical container. 2. The heat treatment apparatus for a semiconductor wafer according to claim 1, wherein the heat treatment apparatus has a size. 3. The semiconductor wafer heat treatment apparatus according to claim 1, wherein a movable portion is provided on the lid or the support shaft of the cylindrical container.