JPH0557170A - Vacuum treatment apparatus - Google Patents

Abstract

PURPOSE:To prevent dust deposition on a substrate to be treated due to the flow of a large amount of gas at the instant of the opening of a gate valve by decreasing the pressure difference between a reaction chamber and a prepara tion chamber when the substrate to be treated is delivered between the chambers. CONSTITUTION:In a vacuum treatment apparatus in which a reaction chamber 2 for vacuum treatment of a substrate to be treated 1 and a preparation chamber 4 are connected by a gate valve 3 admitting delivery of the substrate to be treated 1, a second gate valve 11 having smaller conductance than that of the gate valve 3 is installed in parallel with the gate valve 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing apparatus, and more particularly to a vacuum processing apparatus having a structure in which both a reaction chamber and a preliminary chamber are partitioned by a sluice valve to process a substrate to be processed in a vapor phase growth apparatus or the like. ..

[0002]

2. Description of the Related Art Conventionally, a vacuum processing apparatus of this type has a reaction chamber 2 for processing a substrate 1 to be processed, a preparatory chamber 4 connected to the reaction chamber 2 by a sluice valve 3, as shown in FIG. It has pressure sensors 5 and 6 for measuring the pressure of each chamber and vacuum pumps 7 and 8 for making each chamber a desired degree of vacuum.
In this apparatus, when the substrate 1 to be processed is transferred to and from the preparatory chamber 4 without breaking the vacuum of the reaction chamber 2, the preparatory chamber 4 is evacuated by the vacuum pump 8 and the preparatory chamber 4 is operated by the pressure sensor 6. The method of opening the sluice valve 3 when the chamber 4 is under a predetermined pressure is used. Here, the predetermined pressure is generally set to a value that is slightly lower than the ultimate vacuum of the auxiliary chamber 4 by the vacuum pump 8.

[0003]

However, in the above-mentioned conventional vacuum processing apparatus, the vacuum pump 8 used for the preliminary chamber 4 has a smaller volume than that of the reaction chamber 2.
It is general to use a pump having an exhausting capacity inferior to the vacuum pumps 7 and 8 for the reaction chamber 2. Due to the difference in the performance of the vacuum pump and the volume of each chamber, the ultimate vacuum degree of both chambers inevitably differs. Has occurred. Further, even if vacuum chambers having the same volume and the same performance are used, the ultimate vacuum degree of both chambers varies depending on the degree of deterioration of the vacuum pump and the difference in conductance of the vacuum pipe 9.

For the above-mentioned reason, in the method of opening the sluice valve 3 in a state where the degree of vacuum in the auxiliary chamber 4 has almost reached the ultimate level, the pressure difference caused by the difference in the degree of vacuum in both chambers causes
A gas flow is generated between the reaction chamber 2 and the auxiliary chamber 4. Further, in order to enable the transport of the substrate 1 to be processed without any hindrance, the connection opening portions of both chambers with the sluice valve 3 opened are widely provided, and therefore the conductance is very large and the above-mentioned per unit time is large. The flow volume of the gas is very large. The large amount of gas flow at this moment causes the dust generated in the vacuum processing step and settled in the lower part of the reaction chamber 2 or floating on the inner wall of the reaction chamber to be reattached to the substrate to be processed. However, there is a drawback that the dust has an adverse effect on the next vacuum processing.

[0005]

According to the present invention, a reaction chamber for vacuum-treating a substrate to be processed and a preparatory chamber are connected by a sluice valve capable of transferring the substrate to be processed, and each chamber is provided with a desired chamber. In a vacuum processing apparatus each independently equipped with a vacuum pump for achieving a vacuum degree, in addition to the sluice valve connecting the reaction chamber and the auxiliary chamber, a second sluice valve having a conductance smaller than that of the sluice valve. It has a structure in which are connected in parallel.

[0006]

The present invention will be described below with reference to the drawings. 1 is a configuration diagram showing a vacuum processing apparatus according to a first embodiment of the present invention. The vacuum processing apparatus of the present embodiment is particularly for performing reduced pressure vapor phase growth, and includes a reaction chamber 2 for performing vapor phase growth on the substrate 1 to be processed 2, a preparatory chamber 4 connected to the reaction chamber 2 by a gate valve 3, and 4 Pressure sensors 5 and 6 for measuring pressure, vacuum pumps 7 and 8 for evacuating each chamber, a vacuum pipe 9 and a main valve 10 for connecting the vacuum pump and each chamber, and a second feature of this embodiment. The sluice valve 11 is connected in parallel with the sluice valve 3.

In the figure, reference numeral 12 denotes a heating source 13 for heating the substrate 1 to be processed, which is SiH4 necessary for vapor phase growth,
A reaction gas supply port for NH3 or the like, 14 is an inert gas (N2 or the like) supply port for returning the pressure inside the auxiliary chamber to atmospheric pressure, and 15 is a sluice valve between the outside of the apparatus and the auxiliary chamber 4. In this embodiment, the second
An air-operated valve having a CV value of about 0.3 is used for the sluice valve 11, and a stainless pipe having an inner diameter of about 1/4 inch is used to connect the reaction chamber 2 and the auxiliary chamber 4 to the air-operated valve. Is used.

Next, the operation will be described. The substrate 1 to be processed is first introduced into the preliminary chamber 4 from the outside via the sluice valve 15.
Here, the reaction chamber 2 has already been depressurized by the vacuum pumps 7 and 8. After the introduction of the non-processed substrate, the preparatory chamber 4 is depressurized by the vacuum pump 8 and the pressure sensor 6 detects that the predetermined vacuum degree is reached, and then the second sluice valve 11 having a small conductance is opened. Second sluice valve 1
After confirming that the pressure difference between the reaction chamber 2 and the preparatory chamber 4 is gradually relaxed through 1 and the pressure sensors 5 and 6 have almost the same value, the sluice valve 3 is opened and the substrate 1 to be processed is transported to the reaction chamber 2. To do.

By using the above-described Example 1, a large amount of gas flow that occurs between the reaction chamber 2 and the auxiliary chamber 4 can be suppressed instantaneously, and adheres to the reaction chamber or precipitates in the lower portion of the reaction chamber by vapor phase growth. It is possible to prevent the re-floating of the dust and the re-adhesion to the substrate to be processed. In the vapor phase growth using the conventional technique, dust of 0.3 μm or more was attached to the substrate to be processed at a level of hundreds to thousands, but according to the present embodiment, it is reduced to several to several tens. Can be suppressed.

Next, a second embodiment will be described. As shown in the configuration diagram of FIG. 2, the second sluice valve is the butterfly valve 16
May be used. In the present embodiment, by using the butterfly valve 16, the conductance can be freely changed, and more efficient pressure difference relaxation can be expected as compared with the first embodiment.

[0011]

As described above, according to the present invention, the reaction chamber is connected to the preparatory chamber by the sluice valve capable of transferring the substrate to be processed in order to vacuum-process the substrate to be processed, and each chamber is desired. In a vacuum processing apparatus, each of which is independently equipped with a vacuum pump for adjusting the degree of vacuum to the second chamber, wherein the reaction chamber and the auxiliary chamber have a conductance much smaller than that of the gate valve.
By connecting using the sluice valve, the second sluice valve is opened before the transfer of the substrate to be processed between the reaction chamber and the preliminary chamber, so that a large amount of gas is instantaneously generated due to the pressure difference between the two chambers. It is possible to suppress the flow. Therefore, there is an effect that it is possible to prevent re-floating of the dust generated in the vacuum processing step in the lower part of the reaction chamber or adhered to the inner wall of the reaction chamber and re-adhesion to the substrate to be processed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional vacuum processing apparatus.

[Explanation of symbols]

 1 substrate to be processed 2 reaction chamber 3 sluice valve 4 preparatory chamber 5,6 pressure sensor 7,8 vacuum pump 9 vacuum piping 10 main valve 11 second sluice valve 12 heating source 13 reaction gas supply port 14 inert gas supply port 15 Gate valve 16 Butterfly valve

Claims (1)

[Claims] 1. A reaction chamber for vacuum-processing a substrate to be processed and a preparatory chamber are connected by a sluice valve capable of transferring the substrate to be processed, and a vacuum pump for bringing each chamber to a desired degree of vacuum is provided. In a vacuum processing apparatus independently provided, in addition to the sluice valve connecting the reaction chamber and the auxiliary chamber, a second sluice valve having a conductance smaller than that of the sluice valve is connected in parallel. Vacuum processing equipment.