JP2785745B2 - CVD 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 CVD apparatus for forming a silicon oxide film from an organic silane-based material, and more particularly to a means for maintaining the cleanness of a vacuum exhaust system.

[0002]

2. Description of the Related Art Conventionally, in a CVD apparatus for forming a non-doped or phosphorus- or boron-containing silicon oxide film on a substrate wafer with an organosilane-based material, the supplied material does not completely decompose or react, Is exhausted in an unreacted form, so that it returns to the room temperature state in the exhaust pipe. In this case, since the organic silane-based material such as TEOS is in a liquid state at room temperature, it is liquefied in the exhaust pipe and adheres to the inner wall in the pipe. As a result, there has been a problem that the deposits make the operation of the pressure control valve unstable and cause pressure fluctuations during film formation, thereby making stable film formation impossible.

As a countermeasure against this problem, Japanese Patent Laid-Open Publication No.
In Japanese Patent No. 32, by adding a plasma reaction chamber, a heater capable of applying high-frequency power, and a hydrogen introduction pipe to an exhaust pipe, an unreacted organic silane-based material is decomposed by utilizing a chemical reaction with active hydrogen, A technique capable of reducing deposits due to unreacted organosilane-based material on an exhaust piping system has been disclosed.

FIG. 2 is a schematic view showing this conventional CVD apparatus.
Shown in In the figure, 201 is a reaction vessel used for forming a silicon oxide film, 202 is a boat selectively housed and arranged therein, and 203 is a boat 202
A substrate wafer mounted thereon, 204 is a heater arranged outside the reaction vessel 201, 205 is a flange gap closing both ends of the reaction vessel 201, and an exhaust pipe 208 drawn out of the reaction vessel 201 is a gate valve 206. Connected to the pump 207 via Further, a plasma reaction chamber 210 is provided in the middle of an exhaust pipe 208 from the reaction vessel 201, and a heater 209 with an induction coil for supplying high-frequency power is provided as a heating means on an outer peripheral portion thereof. The introduction pipe 211 is connected.

In such a configuration, the substrate wafer 20
2, a silicon oxide film is formed using a thermal reaction of an organic silane-based material, for example, TEOS and oxygen, which is generated by heating the heater 204. At this time, the temperature in the container 201 is 500-70.
Heat to 0 ° C. The gate valve 206 is provided in the reaction vessel 2
It is used to control the pressure in 01. The unreacted material exhausted from the reaction vessel 201 by the pump 207 is supplied to the plasma reaction chamber 210 added to the exhaust pipe 208.
Pass through. At the same time, hydrogen is introduced into the plasma reaction chamber 210 from the hydrogen introduction pipe 211. When high-frequency power and heat energy are further applied to TEOS and hydrogen by the heater 211 with an induction coil, the unreacted material is decomposed into inorganic products such as C ₂ H ₆ , moisture, and SiO ₂ by a chemical reaction with hydrogen. That is, the amount of deposits on the exhaust pipe 208 can be reduced.

[0006]

However, when a non-doped or phosphorus- or boron-containing silicon oxide film is formed on a substrate wafer with an organosilane-based material by the above-mentioned method, it is necessary as a means for decomposing substances adhering to an exhaust pipe. Hydrogen is introduced. Although it also adds heat energy, hydrogen gas is explosive and very dangerous. For example,
Hydrogen explodes in air in a wide range of 4.1 to 74.2%,
When this is in oxygen, it further spreads to 4.65 to 93.9%. In addition, in the atmosphere of hydrogen such as silane, the energy generated by the decomposition reaction of silane becomes an ignition source and spontaneously ignites. In addition, there is a high risk of ignition and explosion due to friction, static electricity, and the like, and there is a drawback that application to a CVD apparatus is very difficult in terms of safety and practical use is difficult.

Accordingly, an object of the present invention is to provide a CVD apparatus capable of safely reducing the adhesion of unreacted substances without danger of ignition or explosion.

[0008]

CVD apparatus SUMMARY OF THE INVENTION The present invention provides a CVD apparatus for forming a silicon oxide film on a substrate wafer by an organic silane material, Pong from the reaction vessel
A reaction chamber is provided in the exhaust pipe to
A butterfly valve is provided between the reaction chamber and the pump,
The structure is such that 50 to 200 sccm of oxygen is continuously flowed into the reaction chamber, whereby the butterfly valve is used.
The butterfly valve reduces pressure
It is characterized in that the control accuracy can be maintained at a high state for a long time.

[0009]

As described above, the present invention has a structure in which a reaction chamber is provided in the middle of an exhaust pipe from a reaction vessel and oxygen is caused to flow therethrough. And the like, whereby the amount of deposits on the exhaust pipe can be reduced. Further, since oxygen is used without using hydrogen, there is no fear of explosion or the like.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic view showing a CVD apparatus according to a first embodiment of the present invention. In FIG.
1 is a reaction vessel used for forming a silicon oxide film, 102 is a boat installed in the inside thereof, 103 is a substrate wafer mounted on the boat 102 and subjected to CVD processing, 104 is arranged outside the reaction vessel 101 The heated heater 105 is a flange gap for closing both ends of the reaction vessel 101, and an exhaust pipe 108 drawn from the reaction vessel 101 is connected to an exhaust pump 107 via a butterfly valve 106. In addition, the reaction vessel 10
A reaction chamber 110 is provided in the middle of an exhaust pipe 108 between the valve 1 and the butterfly valve 106, and an oxygen introduction pipe 109 is connected to the reaction chamber 110. The reaction chamber 110 is provided with a heater (not shown) so that it can be heated as needed. In such a configuration, the organic silane-based material TEOS is supplied to the substrate wafer 103 at 200 to 400 sccm, and oxygen is added at 100 to 200 sccm. On this occasion,
The temperature inside the reaction vessel 101 is heated to 500 to 700 ° C. The degree of vacuum during CVD deposition is 0.6 to
1.0 Torr. Oxygen introduction pipe 10
In the case where the deposition was performed under the above-mentioned conditions without flowing oxygen (O ₂ ) from No. 9, pressure control with the butterfly valve 106 began to become ineffective when the accumulated time of the depot exceeded 15 hours. At this time, when the exhaust pipe 108 between the flange gap 105 and the pump 107 was disassembled, a large amount of deposits was accumulated in the pipe, and a large amount was observed particularly near the butterfly valve 106.

Therefore, after thoroughly cleaning the pipe 108 and the butterfly valve 106, the pipe 108 and the butterfly valve 106 were attached to the apparatus again, and deposition was performed under the same conditions as above. At this time, oxygen is introduced into the reaction chamber 110 from the oxygen introducing pipe 109 at 50 to 200 scc.
m Always kept flowing. When the exhaust pipe 108 was disassembled in the same manner as above when the accumulated depot time became 15 hours,
The aforementioned deposits were observed between the flange cap 105 and the reaction chamber 110 and in the reaction chamber 110, but the exhaust pipe 108 between the reaction chamber 110 and the pump 107 was observed.
No matter was found inside, including the vicinity of the butterfly valve 106, and it was confirmed that a clean state was maintained.

As a result of the further deposition under these conditions, the accumulated depot time 100
No malfunction of the butterfly valve 106 occurred until the time, and it was confirmed that the introduction of oxygen into the reaction chamber 110 contributed to the prevention of deposits on the piping and the butterfly valve 106 thereafter.

When oxygen is added to unreacted TEOS, Si (OC ₂ H ₅ ) ₄ +120 ₂ → SiO ₂ + 8C
The unreacted material in the reaction of O ₂ + 10H ₂ O is decomposed into inorganic products such as carbon dioxide, moisture, and SiO ₂ by a chemical reaction with oxygen. Therefore, the amount of deposits on the exhaust pipe 108 can be reduced. If the flow rate of oxygen to be introduced is less than 50 sccm, the effect of reducing the deposits in the exhaust pipe 108 becomes thin, and if it is 200 sccm or more, the exhaust capacity of the pump 107 with respect to the reaction vessel 101 is reduced. It is not practical because it causes an increase in particles and a decrease in processing capability of the apparatus.

[0015] In addition, the gas to be introduced is dangerous because it has a high explosive property in the case of hydrogen which has been used conventionally, and TEOS in the case of nitrogen.
Is not carried out, and other inert gases, for example, helium and argon, similarly have little effect on the reduction of the deposits in the exhaust pipe 108 only due to the effect of diluting the unreacted TEOS.

As a second embodiment of the present invention, the first embodiment is for forming a non-doped TEOS-based SiO ₂ film, while the TEOS-based B doped with phosphorus or boron is used.
This is when the PSG film is formed. The semiconductor manufacturing equipment used is the same as that shown in FIG. 1 shown in the first embodiment. The deposition conditions were as follows.
Flow 100 to 400 sccm, and supply oxygen for 100 to 200 sc
cm, phosphine 400-600sccm, TMOB
Is added to each of 20 to 25 sccm. Reaction chamber container 1
01 is 500-700 ° C., and the degree of vacuum in the deposit is 0.
6 to 1.0 Torr is the same as in the first embodiment.
When the deposition was performed under these conditions and without introducing oxygen into the reaction chamber 110, the pressure control by the butterfly valve 106 began to become ineffective when the accumulated time of the deposition exceeded 40 hours. At this time, when the exhaust pipe 108 between the flange cap 105 and the pump 107 was disassembled,
As in the case of the first embodiment, a large amount of deposits were deposited in the pipe, and a large amount was observed particularly near the butterfly valve 106.

Therefore, after thoroughly cleaning the exhaust pipe 108 and the butterfly valve 106, the exhaust pipe 108 and the butterfly valve 106 are attached to the apparatus again.
Deposition was performed under the same conditions as above. At that time, oxygen introduction pipe 1
Oxygen from 09 into reaction chamber 110 50-200 sccm
He kept flowing. When the accumulated depot time reached 50 hours, the exhaust pipe 108 was disassembled in the same manner as described above. And it was confirmed that a clean state was maintained.

In the second embodiment, phosphine or TMOB is used.
Is used, so TE is compared to TEOS and oxygen only.
Although the reaction efficiency with the OS is good and the amount of the deposit is small, the phosphine contained in the deposit is extremely toxic, so that the gas generated from the deposit when the butterfly valve 106 and the exhaust pipe 108 are disassembled and cleaned is reduced. There is concern about the adverse effects on the human body.

The present invention may be applied to a semiconductor manufacturing apparatus using, for example, TEOS alone or another organic silane-based material other than the above-mentioned material gases.

[0020]

As described above, the CVD according to the present invention is described.
According to the apparatus, the reaction chamber is provided in the middle of the exhaust pipe from the reaction vessel, and oxygen is continuously supplied into the reaction chamber. Since the adhesion to the butterfly valve being controlled can be reduced, the pressure control accuracy can be kept high for a long period of time. Further, since the gas flowing into the reaction chamber is oxygen, it is extremely safe as compared with conventionally used hydrogen and the like. From the above effects, according to the present invention, an excellent effect of obtaining a silicon oxide film of lower pollution and higher quality than before can be obtained, and the operation rate of the CVD apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a conventional CVD apparatus.

[Explanation of symbols]

 101, 201 Reaction vessel 102, 202 Boat 103, 203 Substrate wafer 104, 204 Heater 105, 205 Flange cap 106 Butterfly valve 107, 207 Pump 108, 208 Exhaust pipe 109 Oxygen introduction pipe 110 Reaction chamber 206 Gate valve 209 Heater with induction coil 210 Plasma reaction chamber 211 Hydrogen introduction pipe

Claims (1)

(57) [Claims] In a CVD apparatus for forming a silicon oxide film on a substrate wafer using an organosilane-based material , a reaction chamber is provided in the middle of an exhaust pipe from a reaction vessel to a pump .
A butterfly valve between the reaction chamber and the pump.
And a configuration in which oxygen of 50 to 200 sccm is continuously flowed into the reaction chamber, whereby the butterfly
The butterfly valve reduces deposits on the
Pressure control accuracy can be kept high for a long time
CVD apparatus is characterized in that the capacity.