JP2933074B2 - Vapor phase growth apparatus and cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure vapor phase epitaxy apparatus frequently used for manufacturing semiconductor devices and the like, and a cleaning method therefor.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional vapor deposition apparatus employs a heater 1 and a reactor 2 as a quartz outer tube 2a, a quartz inner tube 2b, and a quartz for introducing a wafer into the reactor. Port 3, exhaust pipe 1 for discharging unreacted gas etc. in the furnace
0, a material gas supply port 4 for supplying a gas such as silicon hydride (hereinafter abbreviated as SiH ₄ ) and a flow controller 5 a for controlling the flow rate of the material gas.

[0003] In a reaction furnace 2 in which the exhaust pressure is constantly controlled by a pressure controller 8, SiH _{4 is} deposited at a film forming temperature.
Is supplied from the gas inlet 4 to form a film (hereinafter abbreviated as a CVD film) 16 by a vapor phase growth reaction, and the reaction gas 9 not involved in the reaction is deposited inside the quartz inner tube. 2b to the outer tube 2a to the exhaust pipe 10a, and the CVD film 1 is formed on the inner wall of the reactor 2 as shown in FIG.
6 is deposited.

It is necessary to periodically remove the CVD film 16 adhered to the reaction furnace 2.
a, for desorbing and cleaning the inner quartz tube 2b at room temperature,
These operations take time.

At present, POLY-Si using SiH ₄ gas is used for the purpose of improving the operation rate of the apparatus together with the development of new technology.
In a CVD apparatus for forming a film or the like, a cleaning gas such as chlorine trifluoride (hereinafter abbreviated as CIF ₃ ) is used.
-Situ cleaning is essential.

This is because a gas such as ClF _{3 is} supplied from the cleaning gas inlet 6a at a regular frequency and supplied into the reaction furnace 2 near the film forming temperature while being controlled by the flow rate controller 5b. Since the CVD film 16 attached to the tube 2a, the inner quartz tube 2b, and the quartz boat 3 can be removed and cleaning is not required, the removing operation can be performed in a shorter time than in the related art.

However, since it is difficult to detect the end point of cleaning, damage to quartz parts due to over-etching,
In addition, a residual CVD film occurs due to under-etching.

As a countermeasure for this, as shown in FIG.
Japanese Patent Laid-Open Publication No. Hei 8-306628 discloses a structure in which a thermocouple 18 for monitoring the reaction ripening is provided therein, a cleaning gas is flowed in the reaction tube, and an end point is detected by a change in reaction heat due to etching.

[0009]

The first problem is that the conventional technique cannot prevent damage to quartz.

[0010] As a reason, as shown in FIG. 6, the CIF ₃ gas, which is a cleaning gas, is introduced from the gas inlet 19 and discharged to the gas outlet 20. When the CVD film is removed, the reaction heat becomes constant, and the end point is detected by the reaction heat monitoring thermocouple 18. However, in the temperature controlled reaction tube 17, the temperature change of the reaction heat by the thermocouple occurs. Is small and difficult to detect.

Furthermore, since the introduction amount of the cleaning gas does not change, the lower part of the reaction tube 17 near the gas introduction port is exposed to the CIF ₃ gas for a longer time than the upper part, so that the etching becomes over-etching, and the quartz jig is used. Cause damage.

A second problem is that in the prior art,
-CVD film 16 in reactor 2 after in-situ cleaning
Since it is not possible to directly check the state of adhesion, a great deal of time is spent on checking the damage to quartz parts due to excessive cleaning.

As shown in FIG. 4, the outer peripheral portion of the reactor 2 is covered with a heater 1 and a heat insulating material 7 for raising the temperature to a film forming temperature. This is because it is difficult to easily check the adhesion state of the CVD film 16 attached to the substrate.

Normally, as shown in FIG. 4, when a cleaning gas such as CiF ₃ is introduced into the reaction furnace 2 from the cleaning gas supply port 6a via the flow rate controller 5b, the cleaning gas flows from the inner quartz tube 2b to the outer quartz tube 2a. Since the unreacted gas 9 is discharged, the CVD film 16 attached to the inside of the reaction furnace 2 is removed from the inside to the outside of the quartz inner tube 2b.

However, at present, the state of the inside of the reaction furnace 2 cannot be checked. Therefore, in order to check the state of the inside of the reaction furnace 2 after the in-situ cleaning, the film forming temperature is set to normal temperature, and It is necessary to remove the furnace 2 for confirmation. If the processing time is short, the CVD film 16 is not removed as shown in FIG. 5, whereas if the processing time is long, the quartz jig becomes cloudy and damage to quartz increases.

As a means for checking the condition inside the reactor 2 without detaching the reactor 2, the reactor 2
When components such as a detection sensor for directly monitoring the inside of the device are installed, these components are always exposed to an atmosphere heated to 500 ° C. or more by the heater 1, and in consideration of heat resistance, the vicinity of the heater 1 It is difficult to install.

Even if these components are cooled and installed in order to protect these components, the film forming temperature in the reaction furnace 2 changes and adversely affects the film thickness uniformity. It is difficult to directly monitor the inside of the reaction furnace 2 from the above.

An object of the present invention is to provide a vapor phase growth apparatus having a function of detecting a cleaning end point in in-situ cleaning and performing etching without damaging a quartz jig to improve maintainability, and a technique of a cleaning method therefor. It is in.

[0019]

SUMMARY OF THE INVENTION The present invention has the following arrangement to solve the above-mentioned problems. The gist of the invention according to claim 1 is a vapor phase growth apparatus having a mechanism for introducing a cleaning gas into a reaction furnace having an inner tube and an outer tube, wherein a tip portion is sealed, and the tip portion is A detecting unit provided in the reaction furnace so as to be located on the downstream side of the cleaning gas introduced into the inner tube of the reaction path, and detecting the light intensity at the tip of the detecting unit; And a light intensity detection mechanism provided outside the furnace. The gist of the invention described in claim 2 is that
A mechanism for supplying the cleaning gas between the inner tube and the outer tube of the reaction path, and a tip is sealed so that the tip is located downstream of the cleaning gas supplied from the mechanism. Another detector provided between the inner tube and the outer tube provided, and another light provided outside the reaction furnace for detecting the light intensity of the tip of the detector. The vapor phase growth apparatus according to claim 1, further comprising an intensity detection mechanism. The gist of the invention according to claim 3 resides in the vapor phase growth apparatus according to claim 1 or 2, wherein the vapor phase growth apparatus is a low pressure CVD apparatus.
The gist of the invention according to claim 4 is a cleaning method of a vapor phase growth apparatus for cleaning the inside of a reaction furnace by introducing a cleaning gas into the reaction furnace, wherein the sealing of a detection unit provided in the reaction furnace is performed. A cleaning method for a vapor phase growth apparatus, characterized in that a change in light intensity at the leading end is detected by a light intensity detection mechanism to detect an end point of cleaning. The gist of the invention according to claim 5 is that a detection unit provided inside and outside the inner tube of the reaction path, and a mechanism for supplying the cleaning gas to the inside and outside of the inner tube, respectively, 5. The method according to claim 4, wherein when the end point is detected, the supply of the cleaning gas from the inside of the inner tube is stopped and the supply of the gas is switched to the supply of the gas from the outside of the inner tube. Exist. The gist of the invention of claim 6 resides in the method of cleaning a vapor phase growth apparatus according to claim 4 or 5, wherein the vapor phase growth apparatus is a low pressure CVD apparatus.

In the present invention, the end point of cleaning is detected by monitoring a change in light intensity by using a mechanism for detecting the light intensity of the detection unit installed in the reaction furnace, so that the detection accuracy is improved.

Further, the end point of the cleaning is detected by comparing the intensity of light emitted from the tip of the quartz tube installed inside the inner quartz tube before and after the cleaning with an infrared radiation thermometer, and the cleaning gas supply port is detected. Switch. For this reason, since the light intensity changes when the CVD film is removed by cleaning, the end point can be easily detected, and the quartz jig can be cleaned with little damage.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a vapor phase growth apparatus having an in-situ cleaning system according to a first embodiment of the present invention, FIG. 2 is an explanatory diagram of a cleaning end point detection method, and FIG. FIG. 3 is a cross-sectional view of the vapor phase growth apparatus according to the embodiment. In these figures, the same reference numerals are given to the same components as those in the related art.

The vapor phase growth apparatus of the present invention detects the cleaning end point when performing in-situ cleaning without damaging the quartz jig. More specifically, it has a quartz tube having a tip sealed inside the inner quartz tube, and means for detecting a change in light intensity at the tip of the quartz tube during cleaning.

That is, in the reaction furnace 2 heated by the heater 1 as shown in FIG. 1, a material gas is supplied from a material gas inlet 4 to form a CVD film. The CVD film 16 is discharged from the inner quartz tube 2b to the outer quartz tube 2a, and the CVD film 16 is deposited on the inner wall of the reactor with the passage of time.

A quartz tube 13a having an inner diameter of about 8 to 10 mm and having a sealed tip, an infrared radiation thermometer 11 for measuring a change in light intensity at the tip of the quartz tube outside the apparatus, and the infrared radiation thermometer 11 And a monitor device 12 for displaying and outputting the measured values of. First, assuming that the quartz boat 3 is to be cleaned, the quartz tube 13a is set at the same height as the upper part of the quartz boat 3.

By performing CVD film formation in this state,
The same amount of the CVD film as the quartz boat 3 adheres to the quartz tube 13a. CIF ₃ is introduced into the reactor 2 controlled by the pressure controller 8 from the cleaning gas supply port 6a via the flow rate controller 5b into the reactor 2 as a periodic maintenance for every 5 to 10 μm of CVD film formation. In-situ cleaning is performed at a temperature.

FIG. 2 shows a state in which the CVD film 16 attached to the quartz boat 3 has been removed by in-situ cleaning. In the figure, (a) shows a state before cleaning. In a state where the CVD film 16 of the same degree is attached to the quartz tube 13a and the quartz boat, the light intensity of the measurement point 14 at the tip of the quartz tube 13a is measured by the infrared radiation temperature. It is measured by a total of 11.

When the cleaning is started, the etching is performed from the vicinity of the cleaning gas supply side as shown in FIG. 3B, so that the CVD film is removed from below the quartz boat 3. When the CVD film 16 at the measurement point 14 is removed, the intensity of the emitted light changes depending on the presence or absence of the CVD film 16. This is set as the cleaning end point, and the supply of the cleaning gas is stopped. ),
Cleaning without damaging the entire quartz boat 3 and leaving no film remaining can be performed.

By changing the length and the mounting position of the quartz tube 13a depending on the object to be cleaned, it is possible to detect the cleaning end point of each object.

FIG. 3 is a sectional view of a vapor phase growth apparatus showing a second embodiment of the present invention. In this embodiment, in the vapor phase growth apparatus having the in-situ cleaning system according to the above-described first embodiment, cleaning is further performed on the supply port 6b, the flow rate controller 5c, the outer quartz tube 2a and the inner quartz tube 2b. An injector 15 for blowing out a cleaning gas and a quartz tube 13b are provided therebetween.

After detecting the cleaning end point at the measurement point 14 of the quartz tube 13a, a stop signal is output from the monitor device 12 to the flow controller 5b, and the supply from the cleaning gas supply port 6a is stopped.

At the same time, a supply signal is output to the flow rate controller 5c, the supply signal is supplied from the cleaning gas supply port 6b to the reaction furnace 2 via the injector 15, the end point of the cleaning is detected by the quartz tube 13b, and the supply of the cleaning gas is stopped. That is, the quartz boat 3 and the quartz inner tube 2b
CV as shown in Fig. 5 without receiving damage inside
The D film 16 can be removed, and the quartz tube, the inside of the reaction furnace 2,
The quartz boat 3 can be uniformly cleaned.

[0033]

As described above, the present invention has a quartz tube having a sealed quartz tube and an infrared radiation thermometer for measuring a change in light intensity before and after cleaning of the quartz tube tip. , Quartz outer tube and quartz boat in-si
This is a system that can detect the end point in tu cleaning with high accuracy, and has an effect that damage to a quartz jig can be reduced and cleaning can be performed more uniformly than before.

[Brief description of the drawings]

FIG. 1 shows an in-si system according to a first embodiment of the present invention.
It is sectional drawing of the vapor phase growth apparatus which has a tu cleaning system.

FIG. 2 shows an embodiment of the cleaning end point detection method shown in FIG. 1 (a: before cleaning, b: during cleaning, c:
FIG. 10 is an explanatory diagram showing (after cleaning).

FIG. 3 shows an in-si according to a second embodiment of the present invention.
It is sectional drawing of the vapor phase growth apparatus which has a tu cleaning system.

FIG. 4 is a cross-sectional view of a vapor phase growth apparatus having a prior art in-situ cleaning system.

FIG. 5 is a sectional view of a reactor after in-situ cleaning in a conventional technique.

FIG. 6 is a cross-sectional view of another prior art.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Heater 2 Reaction tube 2a Quartz outer tube 2b Quartz inner tube 3 Quartz boat 4 Material gas inlet 5a, 5b, 5c Flow controller 6a, 6b Cleaning gas inlet 7 Insulation material 8 Pressure controller 9 Unreacted gas 10 Exhaust pipe 11 Infrared ray Radiation thermometer 12 Monitor device 13a, 13b Quartz tube 14 Measurement point 15 Injector 16 CVD film 17 Reaction tube 18 Thermocouple for reaction heat monitoring 19 Gas inlet 20 Gas exhaust

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 16/00-16/56 H01L 21/205 H01L 21/302 H01L 21/3065 H01L 21/31

Claims (6)

(57) [Claims] 1. A vapor-phase growth apparatus having a mechanism for introducing a cleaning gas into a reaction furnace having an inner tube and an outer tube, wherein a tip portion is sealed, and the tip portion is formed in the reaction path. A detector provided in the reactor so as to be located on the downstream side of the cleaning gas introduced into the inside of the tube; and a detector provided outside the reactor for detecting light intensity at the tip of the detector. And a light intensity detecting mechanism. 2. A mechanism for supplying the cleaning gas between the inner tube and the outer tube of the reaction path, wherein a tip is sealed, and the tip is a cleaning gas supplied from the mechanism. Provided to be located on the downstream side,
Another detection unit provided between the inner tube and the outer tube, and another light intensity detection mechanism provided outside the reaction furnace, which detects light intensity at the tip of the detection unit. The vapor phase growth apparatus according to claim 1, further comprising: 3. The vapor deposition apparatus according to claim 1, wherein the vapor deposition apparatus is a low pressure CVD apparatus. 4. A method for cleaning a vapor phase epitaxy apparatus for cleaning a reaction furnace by introducing a cleaning gas into the reaction furnace, the method comprising: A method for cleaning a vapor phase epitaxy apparatus, wherein a change in light intensity is detected by a light intensity detection mechanism to detect an end point of cleaning. 5. A detection unit provided inside and outside the inner tube of the reaction path, and a mechanism for supplying the cleaning gas to the inside and outside of the inner tube, respectively, when an end point is detected in the inner tube. 5. The method according to claim 4, wherein the supply of the cleaning gas from the inside of the inner tube is stopped, and the supply of the gas is switched to the supply of the gas from the outside of the inner tube. 6. The cleaning method for a vapor phase growth apparatus according to claim 4, wherein the vapor phase growth apparatus is a low pressure CVD apparatus.