JPH09213642A - Semiconductor growing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the gas pressure fluctuation thereby enabling the even film-growth by providing a vent hole communicating a material gas path with a heater installation part on the material gas down stream side of a susceptor mounting a semiconductor substrate in a reaction vessel. SOLUTION: Within a semiconductor growing device, a reaction chamber 20 comprising a material gas path is provided with a containing chamber of a susceptor and a heater on the backside of this material gas path 2 keeping away therefrom. On the other hand, a semiconductor substrate 5 mounted on the susceptor 3 on he heater 4 is elevated in the vertical direction through the intermediary of the doorway for the semiconductor substrate 5 including a heater base 21 for going in and out between inside and outside of the reaction chamber 20. The purposes of the susceptor are to mount and heat the semiconductor substrate 5 as well as to heat and thermal-crack the material gas. A vent hole communicating the material gas atmosphere in the material gas path 2 with the virgin gas atmosphere around the heater 4 is provided on the material gas downstream side of the susceptor 3 and the heater 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor growth apparatus such as a CVD apparatus and an epitaxial growth apparatus and a semiconductor growth method, and more particularly to a semiconductor growth apparatus and a semiconductor growth method for preventing a turbulent flow of a source gas due to a purge gas covering a heater. It is a thing.

[0002]

2. Description of the Related Art In a semiconductor growth apparatus that uses gas as a raw material, the raw material gas supplied into a reactor is thermally decomposed by the heat of a heated susceptor, and the decomposition product species is heated and held on the susceptor. The growth is started by reaching the semiconductor substrate. As a method of heating the susceptor, there are high frequency heating, heater heating, and the like. The high frequency heating is a coil for generating a high frequency so as to generate an eddy current in the susceptor itself for heating, and is used when the susceptor is relatively small. This is because when the susceptor is relatively large, it is difficult to maintain a uniform temperature distribution, requires a large amount of electric power, and needs to prevent heating around the coil due to a leakage magnetic field. Because there is.

Therefore, in the case of a relatively large susceptor capable of charging a large number of semiconductor substrates, heater heating is generally used. In this heater heating, the heater is arranged in the immediate vicinity of the susceptor, and the susceptor is heated mainly by the radiant heat of the heater. In the case of this heater heating, the temperature of the heater itself is higher than that of the susceptor, so that the heater is provided so as to avoid the reaction with the raw material gas used for semiconductor growth, and is further provided with a predetermined supply amount of purge gas. There is. In a semiconductor device having a large susceptor, it is common to grow under reduced pressure in order to improve the uniformity of film growth.

[0004]

However, according to the above-described conventional semiconductor growth apparatus by heating with a heater, the pressure of the source gas atmosphere and the purge gas atmosphere are changed due to irregular fluctuations in the pressure of the source gas atmosphere and the pressure of the purge gas atmosphere. The purge gas flows out of the heater to the raw material gas passage side to affect the crystal growth reaction on the substrate, or conversely, the raw material gas flows to the heater side to obtain the desired growth action. There is a problem that the heater is exhausted or the heater reacts with the source gas to deteriorate the heater, and the amount of purge gas exhausted together with the source gas from the exhaust port of the source gas passage becomes irregular, resulting in a flow of the source gas. There is a high possibility that the turbulence will deteriorate the uniformity of semiconductor growth.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a semiconductor growth apparatus and a semiconductor growth method that enable uniform film growth by controlling gas pressure fluctuations. And

[0006]

In order to achieve the above object, according to the present invention, a susceptor for mounting a semiconductor substrate and a heater for heating the susceptor are provided in a reactor while avoiding a source gas passage. In a semiconductor growth apparatus in which a purge gas pipe is connected to an installation section, a semiconductor growth apparatus characterized in that a ventilation hole that connects the source gas passage and the heater installation section is provided on the raw material gas downstream side of the susceptor. provide.

Further, in the present invention, the source gas is supplied into the reaction vessel, and the purge gas is supplied to the heater for heating the susceptor in the reaction vessel so as to cover the heater, the pressure of the source gas atmosphere and the purge gas. Provided is a semiconductor growth method characterized by controlling a pressure difference from the pressure of an atmosphere.

According to the above structure, when a pressure fluctuation occurs in the source gas atmosphere or the purge gas atmosphere, this gas pressure fluctuation is immediately transmitted to both gas atmospheres through the vent holes of the susceptor, and the pressures of both atmospheres are balanced. .

Further, when the pressure fluctuation occurs, the pressure difference between the pressure of the source gas atmosphere and the pressure of the purge gas atmosphere is controlled, and the fluctuation of the pressure of both gas atmospheres is minimized.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a preferred embodiment,
It is characterized in that a means for detecting a pressure difference between the pressure of the raw material gas passage and the pressure of the heater installation portion is provided, and the fluctuation of the pressure difference is controlled based on the detection result.

In another preferred embodiment, a flow rate controller is provided on the purge gas pipe, and the flow rate controller is feedback-controlled based on the detection result of the pressure difference detecting means. There is.

Further, another preferred embodiment is characterized in that the supply amount of the purge gas is feedback-controlled based on the pressure difference.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a basic configuration diagram of a semiconductor growth apparatus according to the present invention. FIG. 2 is an explanatory diagram showing a state in which the susceptor is lowered in the device shown in FIG. In this semiconductor growth apparatus, the reactor 1 is a reaction chamber 2 made of a quartz tube.
0, and the reaction chamber 20 has a source gas passage 2
Is configured.

On the lower surface side of the raw material gas passage 2, avoid the raw material gas passage, and a susceptor and heater accommodating chamber 1 described later.
3 is provided. The bottom plate 14 of the accommodation chamber 13 is made of stainless steel, and the stainless steel bottom plate 14 is provided with an inlet / outlet for notifying a semiconductor substrate.

The semiconductor substrate 5 is the susceptor 3 on the heater 4.
And the heater table 21 as well as the heater table 21 are moved up and down in the vertical direction through the inlet / outlet to be moved in and out of the reaction chamber 20 and the outside (see FIG. 2). The heater 21 is provided with an O-ring 30 for sealing the entrance and exit.

The susceptor 3 mounts the semiconductor substrate 5 and heats it, and also heats the raw material gas to thermally decompose it.

A purge gas line 6 is connected to the storage chamber 13 and an inert gas is introduced to prevent the raw material gas from reacting on the heater.

The heater 4 heats the susceptor 3. The heater 4 is covered with the purge gas introduced from the purge gas line 6 via the flow rate controller 7 so as not to come into contact with the raw material gas.

A gas inlet 8 and a gas exhaust port 9 are provided in the raw material gas passage 2, and an exhaust pipe 11 made of a stainless steel pipe is connected to the gas exhaust port 9 via a connector 10. The exhaust pipe 11 is provided with a pressure gauge 12 for measuring the pressure in the raw material gas passage 2 (pressure in the raw material gas atmosphere).

A storage chamber 1 in which the heater 4 is provided
The bottom plate 14 of No. 3 is provided with a pressure gauge 15 for measuring the pressure of the purge gas atmosphere (the pressure in the accommodation chamber 13) that covers the heater 4 while avoiding the entrance and exit.

A differential pressure gauge 16 for measuring the pressure difference between the source gas atmosphere and the purge gas atmosphere may be provided instead of the two pressure gauges 12 and 15 or in addition to the two pressure gauges 12 and 15.

The pressure gauges 12 and 15 and the differential pressure gauge 16 are connected to the flow rate controller 7. Further, on the downstream side of the raw material gas between the susceptor 3 and the heater 4, a vent hole 17 is provided which connects the raw material gas atmosphere in the raw material gas passage 2 and the purge gas atmosphere around the heater 4.

According to the semiconductor device having the above-mentioned structure, the raw material gas is introduced into the reactor 1 in a depressurized state, and the raw material gas is thermally decomposed mainly by the radiant heat from the susceptor 3 heated by the heater 4 and decomposed. The generated species reach the semiconductor substrate 5 heated and held on the susceptor 3, and the film growth is started. During the film growth, the purge gas is introduced into the accommodation chamber 13 of the heater 4 in parallel with the introduction of the source gas, and the heater 4 is covered with the purge gas, so that the source gas reacts in the vicinity of the heater 4 and is thermally decomposed. Is prevented.

If a slight pressure fluctuation occurs in the source gas atmosphere or the purge gas atmosphere during the film growth,
The fluctuation is caused by the vent hole 1 provided in the susceptor 3 and the heater 4.
It is transmitted to both atmospheres via 7, and the pressures of both atmospheres are immediately balanced. Furthermore, the fluctuation is due to the pressure gauge 12,1.
5 to the differential pressure gauge 16, the detected value is fed back to the flow rate controller 7, the flow rate of the purge gas is controlled by the flow rate controller 7, and the pressures of both atmospheres are balanced with high accuracy.

Since the atmosphere of the raw material gas and the atmosphere of the purge gas are balanced even if the pressure changes as described above, the purge gas flows from the heater 4 side to the raw material gas passage 2 side or vice versa, or from the gas exhaust port 9. The amount of purge gas discharged together with the raw material gas does not become irregular. Therefore, the flow of the source gas can be made constant at all times, and the film growth can be made uniform even in the case of the large susceptor 3.

The vent holes 17 are provided on the downstream side of the raw material gas in order to introduce the purge gas of the heater to the gas exhaust port 9 without affecting the flow of the raw material gas before the reaction on the upstream side of the substrate. .

[0027]

As described above, according to the present invention,
Since a vent hole that connects the source gas atmosphere and the purge gas atmosphere is provided on the downstream side of the source gas of the susceptor, even if pressure fluctuation occurs in the source gas atmosphere or the purge gas atmosphere, the pressure fluctuation is absorbed through the vent hole, Since the pressure of the atmosphere is balanced, it is possible to obtain a high-quality product with uniform film growth without causing turbulence in the flow of the raw material gas as in the conventional apparatus. Furthermore, by controlling the pressure difference between the pressure of the source gas atmosphere and the pressure of the purge gas atmosphere, a product with more uniform film growth can be obtained.

Further, if the supply amount of the purge gas is fed back, the flow rate of the purge gas can be controlled with high accuracy.
The pressure balance between the raw material gas and the purge gas can be finely controlled, and a high quality product with extremely uniform film growth can be obtained.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a semiconductor growth apparatus according to the present invention.

FIG. 2 is an explanatory view showing a state in which the susceptor is lowered in the device of FIG.

[Explanation of symbols]

1: reactor, 2: raw material gas passage, 3: susceptor, 4: heater, 5: semiconductor substrate, 6: purge gas line, 7: flow controller, 8: gas inlet, 9: gas exhaust port, 10: connector, 11: Exhaust pipe, 12: Pressure gauge, 13: Storage chamber, 1
4: bottom plate, 15: pressure gauge, 16: differential pressure gauge, 17: vent hole, 20: reaction chamber, 21: heater stand.

Claims (5)

[Claims] 1. A semiconductor growth apparatus in which a susceptor for mounting a semiconductor substrate and a heater for heating the susceptor are provided in a reactor while avoiding a raw material gas passage, and a purge gas pipe is connected to the heater installation part. A semiconductor growth apparatus characterized in that a vent hole is provided on the downstream side of the raw material gas for communicating the raw material gas passage and the heater installation portion. 2. A detection means for detecting a pressure difference between the pressure of the raw material gas passage and the pressure of the heater installation portion is provided, and the variation of the pressure difference is controlled based on the detection result. The semiconductor growth apparatus according to. 3. A flow rate controller is provided on the purge gas pipe, and the flow rate controller is feedback-controlled based on the detection result of the pressure difference detection means. Semiconductor growth equipment. 4. A raw material gas is supplied into a reaction container, and a purge gas is supplied to a heater for heating a susceptor in the reaction container so as to cover the heater, and the pressure of the raw material gas atmosphere and the pressure of the purge gas atmosphere are A semiconductor growth method characterized by controlling a pressure difference. 5. The semiconductor growth method according to claim 4, wherein the supply amount of the purge gas is feedback-controlled based on the pressure difference.